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Title:
A HEATING SYSTEM AND A METHOD FOR CONTROLLING A HEATING SYSTEM
Document Type and Number:
WIPO Patent Application WO/2016/009418
Kind Code:
A1
Abstract:
A heating system (1) comprises a heat exchange vessel (3) having a first heat exchange coil (9) and a second heat exchange coil (10) located therein. Primary heat exchange water is heated in either or both an oil fired boiler (12) and a back boiler (14) and is circulated between the respective boilers (12) and (14) on the one hand and the heat exchange vessel (3) on the other hand. Heated primary heat exchange water is delivered from the boilers (12,14) through first inlet ports (25) and returned to the boilers (12,14) through first outlet ports (26) substantially midway along the heat exchange vessel (3). A space heating heat exchange circuit (15) is supplied with primary heat exchange water from the heat exchange vessel (3) through a second outlet port (38) and a second inlet port (39). A solar panel (22) supplies heated secondary heat exchange water to the first heat exchange coil (9), while domestic hot water is supplied through the second heat exchange coil (10). A heat dump heat exchanger (24) cools the primary heat exchange water on the primary heat exchange water in the heat exchange vessel (3) exceeding a predefined upper temperature.

Inventors:
KEANE BERNARD MICHAEL (IE)
Application Number:
PCT/IE2015/000009
Publication Date:
January 21, 2016
Filing Date:
July 14, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
KEANE BERNARD MICHAEL (IE)
International Classes:
F24D3/08; F24D11/00; F24D12/02; F24D19/10; F28D20/00
Foreign References:
DE202012001555U12013-02-18
DE19648652A11997-05-28
EP2503276A12012-09-26
AU2010200738A12010-09-16
EP1403593A22004-03-31
DE4301723A11993-09-09
DE102011005231A12012-09-13
DE202011003668U12011-07-14
Other References:
None
Attorney, Agent or Firm:
F.F. GORMAN & CO. (Dublin 2, IE)
Download PDF:
Claims:
Claims

1. A heating system comprising a heat exchange vessel extending between a lower end and an upper end, and defining a hollow interior region, the heat exchange vessel comprising a first inlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, a first outlet port communicating with the hollow interior region of the heat exchange vessel at a location intermediate the lower and upper ends of the heat exchange vessel spaced apart downwardly from the location at which the first inlet port communicates with the hollow interior region of the heat exchange vessel, a second outlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a second inlet port communicating with the hollow interior region of the heat exchange vessel adjacent the lower end of the heat exchange vessel and spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, a first heat source connected to the heat exchange vessel through a first flow pipe connecting a flow port of the first heat source with the first inlet port, and a first return pipe connecting a return port of the first heat source with the first outlet port for circulation of a primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel, and a space heating heat exchange means connected to the heat exchange vessel through a second flow pipe connecting the space heating heat exchange means with the second outlet port, and a second return pipe connecting the space heating heat exchange means with the second inlet port for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means.

2. A heating system as claimed in Claim 1 in which a first heat exchange element for accommodating a secondary heat exchange medium therethrough is located in the hollow interior region of the heat exchange vessel at a position between the location at which the first outlet port and the second inlet port communicate with the hollow interior region of the heat exchange vessel, the first heat exchange element extending between a secondary inlet port and a secondary outlet port, the secondary inlet and outlet ports extending from the first heat exchange element sealably through the heat exchange vessel, the first heat exchange element being configured to exchange heat between the secondary heat exchange medium and the primary heat exchange medium and to isolate the secondary heat exchange medium in the first heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

3. A heating system as claimed in Claim 2 in which a second heat source is connected to the first heat exchange element in the heat exchange vessel through a secondary flow pipe connecting a flow port of the second heat source with the secondary inlet port, and a secondary return pipe connecting a return port of the second heat source with the secondary outlet port for circulation of the secondary heat exchange medium between the second heat source and the first heat exchange element.

4. A heating system as claimed in Claim 2 or 3 in which the secondary outlet port extends through the heat exchange vessel at a location downwardly from the location through which the secondary inlet port extends through the heat exchange vessel. 5. A heating system as claimed in any of Claims 2 to 4 in which the secondary outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the second inlet port communicates with the hollow interior region of the heat exchange vessel, and the secondary inlet port extends through the heat exchange vessel at a location spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

6. A heating system as claimed in any preceding claim in which a third outlet port communicates with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a third inlet port communicates with the hollow interior region of the heat exchange vessel.

7. A heating system as claimed in Claim 6 in which a heat dump heat exchanger is connected with the heat exchange vessel through a third flow pipe connecting the third outlet port with an inlet port of the heat dump heat exchanger, and a third return pipe connecting the third inlet port with an outlet port of the heat dump heat exchanger for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger.

8. A heating system as claimed in Claim 6 or 7 in which the third inlet port communicates with the hollow interior region of the heat exchange vessel at a level below the level at which the third outlet port communicates with the hollow interior region of the heat exchange vessel.

9. A heating system as claimed in any of Claims 6 to 8 in which the third inlet port communicates with the hollow interior region of the heat exchange vessel at a level intermediate the levels at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel.

10. A heating system as claimed in any of Claims 6 to 9 in which the ratio of the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, to the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel is in the range of 1:1 and 2:1.

11. A heating system as claimed in any preceding claim in which a second heat exchange element for accommodating water therethrough for heating thereof is located in the hollow interior region of the heat exchange vessel at a position between the locations at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the second heat exchange element extending between a water inlet port and a water outlet port, the water inlet port and the water outlet port extending from the second heat exchange element sealably through the heat exchange vessel, and the second heat exchange element is configured for heat exchange between the primary heat exchange medium in the heat exchange vessel and water in the second heat exchange element, and to isolate water in the second heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

12. A heating system as claimed in Claim 11 in which the water outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the water inlet port extends through the heat exchange vessel.

13. A heating system as claimed in Claim 11 or 12 in which the location through which the water inlet port extends through the heat exchange vessel is spaced apart downwardly from the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel, and is spaced apart upwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

14. A heating system as claimed in any of Claims 11 to 13 in which the location at which the water outlet port extends from the heat exchange vessel is spaced apart upwardly from the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel.

15. A heating system as claimed in any of Claims 11 to 14 in which the water outlet port extends through the heat exchange vessel at a level substantially similar to the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel.

16. A heating system as claimed in any preceding claim in which a first temperature sensor is located in the heat exchange vessel for monitoring the temperature at a location spaced apart upwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

17. A heating system as claimed in Claim 16 in which a first circulating pump is provided for circulating the primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel, the first circulating pump being responsive to temperature sensed by the first temperature sensor for circulating the primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel.

18. A heating system as claimed in Claim 16 or 17 in which the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance in the range of 5% to 20% of the distance the first inlet port is spaced apart upwardly from the first outlet port.

19. A heating system as claimed in any of Claims 16 to 18 in which the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance in the range of 10% to 15% of the distance the first inlet port is spaced apart upwardly from the first outlet port.

20. A heating system as claimed in any of Claims 16 to 19 in which the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance of approximately 12% of the distance the first inlet port is spaced apart upwardly from the first outlet port.

21. A heating system as claimed in any preceding claim in which a second temperature sensor is located in the heat exchange vessel at a location spaced apart downwardly from the location at which the second outlet port communicates with the hollow interior region of the heat exchange vessel, and a second circulating pump is provided for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means, the second circulating pump being responsive to temperature sensed by the second temperature sensor for

5 circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means.

22. A heating system as claimed in Claim 21 in which the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a distance in the l o range of 5% to 20% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

23. A heating system as claimed in Claim 21 or 22 in which the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a distance in

15 the range of 10% to 15% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

24. A heating system as claimed in any of Claims 21 to 23 in which the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a

20 distance of approximately 12% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

25. A heating system as claimed in any preceding claim in which a third temperature sensor is located in the heat exchange vessel, the third temperature sensor being located at a location intermediate

25 the locations at which the first inlet and outlet ports communicate with the hollow interior region of the heat exchange vessel, and a third circulating pump is provided for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger, the third circulating pump being responsive to temperature sensed by the third temperature sensor for circulating the primary heat exchange medium between the hollow interior region of the heat

30 exchange vessel and the heat dump heat exchanger.

26. A heating system as claimed in Claim 25 in which the third temperature sensor is located in the heat exchange vessel at a level substantially similar to the level of the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel, but spaced apart slightly downwardly therefrom.

27. A heating system as claimed in any preceding claim in which a fourth temperature sensor is located in the heat exchange vessel at a location intermediate the location through which the secondary inlet port and the secondary outlet port extend through the heat exchange vessel, and a secondary circulating pump is provided for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element, the secondary circulating pump being responsive to temperature sensed by the fourth temperature sensor for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element.

28. A heating system as claimed in Claim 27 in which the fourth temperature sensor is located substantially midway between the locations through which the secondary inlet and outlet ports extend through the heat exchange vessel.

29. A heating system as claimed in Claim 27 or 28 in which a fifth temperature sensor is located adjacent the second heat source for monitoring the temperature of the secondary heat exchange medium, and the secondary circulating pump is responsive to temperature sensed by the fifth temperature sensor for controlling circulation of the secondary heat exchange medium between the second heat source and the first heat exchange element.

30. A heating system as claimed in Claim 29 in which the secondary circulating pump is responsive to a difference between the temperature sensed by the fifth temperature sensor and the temperature sensed by the fourth temperature sensor being greater than a predefined temperature difference value for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element.

31. A heating system as claimed in Claim 29 or 30 in which the fifth temperature sensor is located for monitoring the temperature of the secondary heat exchange medium adjacent the flow port of the second heat source.

32. A heating system as claimed in any of Claims 27 to 31 in which the secondary circulating pump is located between the return port of the second heat source and the secondary outlet port from the first heat exchange element.

33. A heating system as claimed in any of Claims 27 to 32 in which the secondary circulating pump comprises a modulating pump.

34. A heating system as claimed in any preceding claim in which a control means is provided for controlling the operation of the heating system, the control means being configured to read signals from the temperature sensors indicative of the temperature of the respective heat exchange media monitored thereby, and for controlling the operation of the respective circulating pumps in response to the respective sensed temperatures.

35. A heating system as claimed in any preceding claim in which the first heat source is configured to heat the primary heat exchange medium to a temperature higher than the temperature to which the second heat source is configured to heat the secondary heat exchange medium.

36. A heating system as claimed in any preceding claim in which the second heat source comprises a solar panel for heating the secondary heat exchange medium.

37. A heating system as claimed in any preceding claim in which the first heat source comprises one or more of an oil fired boiler, a gas fired boiler, a solid fuel fired boiler, a wood chip burner/boiler, a back boiler, a geothermal heat pump and an air to water heat pump.

38. A heating system as claimed in any preceding claim in which the heat dump heat exchanger comprises a fan assisted heat exchanger.

39. A heating system as claimed in any preceding claim in which the second heat exchange element is configured for heating water to produce domestic hot water.

40. A heating system as claimed in any preceding claim in which the space heating heat exchange means comprises at least one space heating heat exchange circuit.

41. A heating system as claimed in Claim 38 in which each heat exchange circuit comprises one of a circuit comprising a plurality of space heating heat exchangers, and an underfloor heat exchange circuit.

42. A heating system as claimed in any preceding claim in which a plurality of first inlet ports are provided to the hollow interior region of the heat exchange vessel, and a plurality of first outlet ports are provided from the hollow interior region of the heat exchange vessel for connecting respective ones of a plurality of first heat sources to the heat exchange vessel.

43. A heating system as claimed in any preceding claim in which a plurality of second inlet ports are provided to the hollow interior region of the heat exchange vessel, and a plurality of second outlet ports are provided from the hollow interior region of the heat exchange vessel for connecting respective corresponding ones of a plurality of space heating heat exchange means to the heat exchange vessel.

44. A heating system as claimed in any preceding claim in which the secondary heat exchange medium comprises a heat exchange liquid. 45. A heating system as claimed in any preceding claim in which the secondary heat exchange medium comprises water,

46. A heating system as claimed in any preceding claim in which the secondary heat exchange medium comprises a water/glycol mixture.

47. A heating system as claimed in any preceding claim in which the primary heat exchange medium comprises a heat exchange liquid.

48. A heating system as claimed in any preceding claim in which the primary heat exchange medium comprises water.

49. A heat exchange vessel for the heat exchange system as claimed in any preceding claim, the heat exchange vessel extending between a lower end and an upper end, and defining a hollow interior region, the heat exchange vessel comprising a first inlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, the first inlet port being configured for receiving a primary heat exchange medium from a first heat source, a first outlet port communicating with the hollow interior region of the heat exchange vessel at a location intermediate the lower and upper ends of the heat exchange vessel spaced apart downwardly from the location at which the first inlet port communicates with the hollow interior region of the heat exchange vessel, the first outlet port being configured for returning the primary heat exchange medium to the first heat source, a second outlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, the second outlet port being configured for delivering the primary heat exchange medium to a space heating heat exchange means, and a second inlet port communicating with the hollow interior region of the heat exchange vessel adjacent the lower end of the heat exchange vessel and spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, the second inlet port being configured to receive the primary heat exchange medium from the space heating heat exchange means.

50. A heat exchange vessel as claimed in Claim 49 in which a first heat exchange element for accommodating a secondary heat exchange medium therethrough is located in the hollow interior region of the heat exchange vessel at a position between the location at which the first outlet port and the second inlet port communicate with the hollow interior region of the heat exchange vessel, the first heat exchange element extending between a secondary inlet port and a secondary outlet port, the secondary inlet and outlet ports extending from the first heat exchange element sealably through the heat exchange vessel, the first heat exchange element being configured to communicate with a second heat source for circulation of the secondary heat exchange medium therebetween, to exchange heat between the secondary heat exchange medium and the primary heat exchange medium and to isolate the secondary heat exchange medium in the first heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

51. A heat exchange vessel as claimed in Claim 50 in which the secondary outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the second inlet port communicates with the hollow interior region of the heat exchange vessel, and the secondary inlet port extends through the heat exchange vessel at a location spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

52. A heat exchange vessel as claimed in any of Claims 49 to 51 in which a third outlet port communicates with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a third inlet port communicates with the hollow interior region of the heat exchange vessel at a level intermediate the levels at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the third inlet and outlet ports being configured for connecting to a heat dump heat exchanger for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger.

53. A heat exchange vessel as claimed in Claim 52 in which the ratio of the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, to the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel is in the range of 1:1 and 2:1.

54. A heat exchange vessel as claimed in any of Claims 49 to 53 in which a second heat exchange element for accommodating water therethrough for heating thereof is located in the hollow interior region of the heat exchange vessel at a position between the locations at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the second heat exchange element extending between a water inlet port and a water outlet port, the water inlet port and the water outlet port extending from the second heat exchange element sealably through the heat exchange vessel, and the second heat exchange element is configured for heat exchange between the primary heat exchange medium and water in the second heat exchange element, and to isolate water in the second heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel. 55. A method for controlling the operation of the heating system as claimed in any of Claims 1 to 48, the method comprising the steps of reading a signal from the first temperature sensor, and activating the first circulating pump in response to the signal read from the first temperature sensor being indicative of the temperature of the primary heat exchange medium in the hollow interior region of the heat exchange vessel adjacent the first temperature sensor dropping below a first predefined temperature, and deactivating the first circulating pump in response to the signal read from the first temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the first temperature exceeding a second predefined temperature.

56. A method as claimed in Claim 55 in which a signal is read from the second temperature sensor, and the second circulating pump is deactivated in response to the signal read from the second temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the second temperature sensor falling below a third predefined temperature, and the second circulating pump is activated in response to the signal read from the second temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the second temperature sensor exceeding a fourth predefined temperature.

57. A method as claimed in Claim 55 or 56 in which a signal is read from the third temperature sensor, and the third circulating pump is activated in response to the signal read from the third temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the third temperature sensor exceeding a fifth predefined temperature, and the third circulating pump is deactivated in response to the signal read from the third temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the third temperature sensor falling below a sixth predefined temperature.

58. A method as claimed in Claim 57 in which the fan of the heat dump heat exchanger is activated and deactivated on activation and deactivation, respectively, of the third circulating pump. 59. A method as claimed in any of Claims 55 to 58 in which signals are read from the fourth and fifth temperature sensors, and the secondary circulating pump is activated in response to the signals read from the fourth and fifth temperature sensors being indicative of the temperature difference of the temperature of the secondary heat exchange medium adjacent the fifth temperature sensor less the temperature of the primary heat exchange medium adjacent the fourth temperature sensor exceeding a first predefined temperature difference value.

60. A method as claimed in Claim 59 in which the secondary circulating pump is deactivated in response to the difference of the temperature of the secondary heat exchange medium adjacent the fifth temperature sensor less the temperature of the primary heat exchange medium adjacent the fourth temperature sensor falling below a second predefined temperature difference value.

61. A method as claimed in Claim 60 in which the second predefined temperature difference value does not exceed 2°C.

62. A method as claimed in Claim 60 or 61 in which the second predefined temperature difference value is at least re. 63. A method as claimed in any of Claims 60 to 62 in which the second predefined temperature difference value lies in the range of 1°C to 3°C.

64. A method as claimed in any of Claims 59 to 63 in which the first predefined temperature difference value is at least 5°C.

65. A method as claimed in any of Claims 59 to 64 in which the first predefined temperature difference value is at least 7°C.

66. A method as claimed in any of Claims 59 to 65 in which the first predefined temperature difference value lies in the range of 5°C to 9°C.

Description:
"A heating system and a method for controlling a heating system"

The present invention relates to a heating system, and in particular, to a heating system for space heating, and the invention also relates to a method for controlling a heating system, and to a heat exchange vessel for use in a heating system.

Heating systems for space heating are well known, and in general, include a heat exchange vessel for containing a primary heat exchange medium, typically water. The primary heat exchange water is heated by a heat source, for example, an oil or gas fired boiler, and the heated heat exchange water is circulated between the heat source and the heat exchange vessel. One or more space heating heat exchange circuits are connected to the heat exchange vessel, and the primary heat exchange water in the heat exchange vessel is circulated through the one or more space heating heat exchange circuits between the heat exchange vessel and the space heating heat exchange circuits for space heating. It is also known to connect a solar panel of the type which heats a separate heat exchange medium, for example, a low temperature freezing point water/glycol mixture to the heat exchange vessel for circulating the solar heated heat exchange water/glycol mixture between the solar panel, and typically, a heat exchanger located within the heat exchange vessel. The heat exchanger located within the heat exchange vessel isolates the solar heated heat exchange water/glycol mixture from the primary heat exchange water in the heat exchange vessel, and heat is transferred to the primary heat exchange water from the solar heated heat exchange water/glycol mixture within the heat exchange vessel.

However, such heat exchange systems suffer from a number of disadvantages, for example, control of the temperature of the primary heat exchange water/glycol mixture within the heat exchange vessel can be problematical, particularly in warm, sunny weather. A further disadvantage of such heating systems is that they do not operate particularly efficiently.

There is therefore a need for a heating system which addresses at least some of the problems of known heating systems. The present invention is directed towards providing such a heat exchange system, and the invention is also directed towards providing a method for controlling a heat exchange system, and further, the invention is directed towards providing a heat exchange vessel for use in a heat exchange system. According to the invention there is provided a heating system comprising a heat exchange vessel extending between a lower end and an upper end, and defining a hollow interior region, the heat exchange vessel comprising a first inlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, a first outlet port communicating with the hollow interior region of the heat exchange vessel at a location intermediate the lower and upper ends of the heat exchange vessel spaced apart downwardly from the location at which the first inlet port communicates with the hollow interior region of the heat exchange vessel, a second outlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a second inlet port communicating with the hollow interior region of the heat exchange vessel adjacent the lower end of the heat exchange vessel and spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, a first heat source connected to the heat exchange vessel through a first flow pipe connecting a flow port of the first heat source with the first inlet port, and a first return pipe connecting a return port of the first heat source with the first outlet port for circulation of a primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel, and a space heating heat exchange means connected to the heat exchange vessel through a second flow pipe connecting the space heating heat exchange means with the second outlet port, and a second return pipe connecting the space heating heat exchange means with the second inlet port for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means.

In one aspect of the invention a first heat exchange element for accommodating a secondary heat exchange medium therethrough is located in the hollow interior region of the heat exchange vessel at a position between the location at which the first outlet port and the second inlet port communicate with the hollow interior region of the heat exchange vessel, the first heat exchange element extending between a secondary inlet port and a secondary outlet port, the secondary inlet and outlet ports extending from the first heat exchange element sealably through the heat exchange vessel, the first heat exchange element being configured to exchange heat between the secondary heat exchange medium and the primary heat exchange medium and to isolate the secondary heat exchange medium in the first heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

Preferably, a second heat source is connected to the first heat exchange element in the heat exchange vessel through a secondary flow pipe connecting a flow port of the second heat source with.the secondary inlet port, and a secondary return pipe connecting a return port of the second heat source with the secondary outlet port for circulation of the secondary heat exchange medium between the second heat source and the first heat exchange element. Advantageously, the secondary outlet port extends through the heat exchange vessel at a location downwardly from the location through which the secondary inlet port extends through the heat exchange vessel.

In one aspect of the invention the secondary outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the second inlet port communicates with the hollow interior region of the heat exchange vessel, and the secondary inlet port extends through the heat exchange vessel at a location spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel. In another aspect of the invention a third outlet port communicates with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a third inlet port communicates with the hollow inferior region of the heat exchange vessel.

In a further aspect of the invention a heat dump heat exchanger is connected with the heat exchange vessel through a third flow pipe connecting the third outlet port with an inlet port of the heat dump heat exchanger, and a third return pipe connecting the third inlet port with an outlet port of the heat dump heat exchanger for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger. In one aspect of the invention the third inlet port communicates with the hollow interior region of the heat exchange vessel at a level below the level at which the third outlet port communicates with the hollow interior region of the heat exchange vessel.

Advantageously, the third inlet port communicates with the hollow interior region of the heat exchange vessel at a level intermediate the levels at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel.

Preferably, the ratio of the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, to the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel is in the range of 1:1 and 2:1.

In another aspect of the invention a second heat exchange element for accommodating water therethrough for heating thereof is located in the hollow interior region of the heat exchange vessel at a position between the locations at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the second heat exchange element extending between a water inlet port and a water outlet port, the water inlet port and the water outlet port extending from the second heat exchange element sealably through the heat exchange vessel, and the second heat exchange element is configured for heat exchange between the primary heat exchange medium in the heat exchange vessel and water in the second heat exchange element, and to isolate water in the second heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

In one aspect of the invention the water outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the water inlet port extends through the heat exchange vessel.

In another aspect of the invention the location through which the water inlet port extends through the heat exchange vessel is spaced apart downwardly from the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel, and is spaced apart upwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

Preferably, the location at which the water outlet port extends from the heat exchange vessel is spaced apart upwardly from the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel.

Advantageously, the water outlet port extends through the heat exchange vessel at a level substantially similar to the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel, In one aspect of the invention a first temperature sensor is located in the heat exchange vessel for monitoring the temperature at a location spaced apart upwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel.

Preferably, a first circulating pump is provided for circulating the primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel, the first circulating pump being responsive to temperature sensed by the first temperature sensor for circulating the primary heat exchange medium between the first heat source and the hollow interior region of the heat exchange vessel.

In one aspect of the invention the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance in the range of 5% to 20% of the distance the first inlet port is spaced apart upwardly from the first outlet port.

Preferably, the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance in the range of 10% to 15% of the distance the first inlet port is spaced apart upwardly from the first outlet port. Advantageously, the location of the first temperature sensor in the heat exchange vessel is spaced apart upwardly from the first outlet port a distance of approximately 12% of the distance the first inlet port is spaced apart upwardly from the first outlet port.

In another aspect of the invention a second temperature sensor is located in the heat exchange vessel at a location spaced apart downwardly from the location at which the second outlet port communicates with the hollow interior region of the heat exchange vessel, and a second circulating pump is provided for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means, the second circulating pump being responsive to temperature sensed by the second temperature sensor for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the space heating heat exchange means.

Preferably, the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a distance in the range of 5% to 20% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

Advantageously, the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a distance in the range of 10% to 15% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

Ideally, the location of the second temperature sensor in the heat exchange vessel is spaced apart downwardly from the second outlet port a distance of approximately 12% of the distance the first outlet port is spaced apart downwardly from the second outlet port.

In another aspect of the invention a third temperature sensor is located in the heat exchange vessel, the third temperature sensor being located at a location intermediate the locations at which the first inlet and outlet ports communicate with the hollow interior region of the heat exchange vessel, and a third circulating pump is provided for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger, the third circulating pump being responsive to temperature sensed by the third temperature sensor for circulating the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger.

Preferably, the third temperature sensor is located in the heat exchange vessel at a level substantially similar to the level of the location at which the third inlet port communicates with the hollow interior region of the heat exchange vessel, but spaced apart slightly downwardly therefrom. In another aspect of the invention a fourth temperature sensor is located in the heat exchange vessel at a location intermediate the location through which the secondary inlet port and the secondary outlet port extend through the heat exchange vessel, and a secondary circulating pump is provided for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element, the secondary circulating pump being responsive to temperature sensed by the fourth temperature sensor for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element. Preferably, the fourth temperature sensor is located substantially midway between the locations through which the secondary inlet and outlet ports extend through the heat exchange vessel. In another aspect of the invention a fifth temperature sensor is located adjacent the second heat source for monitoring the temperature of the secondary heat exchange medium, and the secondary circulating pump is responsive to temperature sensed by the fifth temperature sensor for controlling circulation of the secondary heat exchange medium between the second heat source and the first heat exchange element.

Preferably, the secondary circulating pump is responsive to a difference between the temperature sensed by the fifth temperature sensor and the temperature sensed by the fourth temperature sensor being greater than a predefined temperature difference value for circulating the secondary heat exchange medium between the second heat source and the first heat exchange element.

Advantageously, the fifth temperature sensor is located for monitoring the temperature of the secondary heat exchange medium adjacent the flow port of the second heat source.

Preferably, the secondary circulating pump is located between the return port of the second heat source and the secondary outlet port from the first heat exchange element.

Advantageously, the secondary circulating pump comprises a modulating pump.

In another aspect of the invention a control means is provided for controlling the operation of the heating system, the control means being configured to read signals from the temperature sensors indicative of the temperature of the respective heat exchange media monitored thereby, and for controlling the operation of the respective circulating pumps in response to the respective sensed temperatures.

Preferably, the first heat source is configured to heat the primary heat exchange medium to a temperature higher than the temperature to which the second heat source is configured to heat the secondary heat exchange medium.

In another aspect of the invention the second heat source comprises a solar panel for heating the secondary heat exchange medium.

In another aspect of the invention the first heat source comprises one or more of an oil fired boiler, a gas fired boiler, a solid fuel fired boiler, a wood chip burner/boiler, a back boiler, a geothermal heat pump and an air to water heat pump. Preferably, the heat dump heat exchanger comprises a fan assisted heat exchanger.

Advantageously, the second heat exchange element is configured for heating water to produce domestic hot water.

In another aspect of the invention the space heating heat exchange means comprises at least one space heating heat exchange circuit.

In one aspect of the invention each heat exchange circuit comprises one of a circuit comprising a plurality of space heating heat exchangers, and an underfloor heat exchange circuit.

In a further aspect of the invention a plurality of first inlet ports are provided to the hollow interior region of the heat exchange vessel, and a plurality of first outlet ports are provided from the hollow interior region of the heat exchange vessel for connecting respective ones of a plurality of first heat sources to the heat exchange vessel.

In a still further aspect of the invention a plurality of second inlet ports are provided to the hollow interior region of the heat exchange vessel, and a plurality of second outlet ports are provided from the hollow interior region of the heat exchange vessel for connecting respective corresponding ones of a plurality of space heating heat exchange means to the heat exchange vessel.

Preferably, the secondary heat exchange medium comprises a heat exchange liquid.

Advantageously, the secondary heat exchange medium comprises water, and preferably, a water/glycol mixture.

In another aspect of the invention the primary heat exchange medium comprises a heat exchange liquid. Preferably, the primary heat exchange medium comprises water.

Additionally the invention provides a heat exchange vessel for the heat exchange system according to the invention, the heat exchange vessel extending between a lower end and an upper end, and defining a hollow interior region, the heat exchange vessel comprising a first inlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, the first inlet port being configured for receiving a primary heat exchange medium from a first heat source, a first outlet port communicating with the hollow interior region of the heat exchange vessel at a location intermediate the lower and upper ends of the heat exchange vessel spaced apart downwardly from the location at which the first inlet port communicates with the hollow interior region of the heat exchange vessel, the first outlet port being configured for returning the primary heat exchange medium to the first heat source, a second outlet port communicating with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, the second outlet port being configured for delivering the primary heat exchange medium to a space heating heat exchange means, and a second inlet port communicating with the hollow interior region of the heat exchange vessel adjacent the lower end of the heat exchange vessel and spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, the second inlet port being configured to receive the primary heat exchange medium from the space heating heat exchange means.

Preferably, a first heat exchange element for accommodating a secondary heat exchange medium therethrough is located in the hollow interior region of the heat exchange vessel at a position between the location at which the first outlet port and the second inlet port communicate with the hollow interior region of the heat exchange vessel, the first heat exchange element extending between a secondary inlet port and a secondary outlet port, the secondary inlet and outlet ports extending from the first heat exchange element sealably through the heat exchange vessel, the first heat exchange element being configured to communicate with a second heat source for circulation of the secondary heat exchange medium therebetween, to exchange heat between the secondary heat exchange medium and the primary heat exchange medium and to isolate the secondary heat exchange medium in the first heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

Advantageously, the secondary outlet port extends through the heat exchange vessel at a location spaced apart upwardly from the location at which the second inlet port communicates with the hollow interior region of the heat exchange vessel, and the secondary inlet port extends through the heat exchange vessel at a location spaced apart downwardly from the location at which the first outlet port communicates with the hollow interior region of the heat exchange vessel. Preferably, a third outlet port communicates with the hollow interior region of the heat exchange vessel at a location adjacent the upper end of the heat exchange vessel, and a third inlet port communicates with the hollow interior region of the heat exchange vessel at a level intermediate the levels at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the third inlet and outlet ports being configured for connecting to a heat dump heat exchanger for circulation of the primary heat exchange medium between the hollow interior region of the heat exchange vessel and the heat dump heat exchanger;

Preferably, the ratio of the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first outlet port communicates with the hollow interior region of the heat exchange vessel, to the spacing between the level at which the third inlet port communicates with the hollow interior region of the heat exchange vessel and the level at which the first inlet port communicates with the hollow interior region of the heat exchange vessel is in the range of 1:1 and 2:1.

In another aspect of the invention a second heat exchange element for accommodating water therethrough for heating thereof is located in the hollow interior region of the heat exchange vessel at a position between the locations at which the first inlet port and the first outlet port communicate with the hollow interior region of the heat exchange vessel, the second heat exchange element extending between a water inlet port and a water outlet port, the water inlet port and the water outlet port extending from the second heat exchange element sealably through the heat exchange vessel, and the second heat exchange element is configured for heat exchange between the primary heat exchange medium and water in the second heat exchange element, and to isolate water in the second heat exchange element from the primary heat exchange medium in the hollow interior region of the heat exchange vessel.

The invention also provides a method for controlling the operation of the heating system according to the invention, the method comprising the steps of reading a signal from the first temperature sensor, and activating the first circulating pump in response to the signal read from the first temperature sensor being indicative of the temperature of the primary heat exchange medium in the hollow interior region of the heat exchange vessel adjacent the first temperature sensor dropping below a first predefined temperature, and deactivating the first circulating pump in response to the signal read from the first temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the first temperature exceeding a second predefined temperature. I n one aspect of the invention the first predefined temperature lies in the range of 55°C to 59°C, and preferably, lies in the range of 56°C to 58°C, and advantageously, the first predefined temperature is approximately 57"C.

In one aspect of the invention the second predefined temperature lies in the range of 60°C to 64°C, and preferably, likes in the range of 61 °C to 63°C, and advantageously, the second predefined temperature is approximately 62°C.

In one aspect of the invention a signal is read from the second temperature sensor, and the second circulating pump is deactivated in response to the signal read from the second temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the second temperature sensor falling below a third predefined temperature, and the second circulating pump is activated in response to the signal read from the second temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the second temperature sensor exceeding a fourth predefined temperature.

In one aspect of the invention the third predefined temperature lies in the range of 47°C to 51 °C, and preferably, lies in the range of 48°C to 50°C, and advantageously, the third predefined temperature is approximately 49°C.

In another aspect of the invention the fourth predefined temperature lies in the range of 62°C to 67°C, and preferably, lies in the range of 63°C to 66°C, and advantageously, the fourth predefined temperature is approximately 65°C.

In another aspect of the invention a signal is read from the third temperature sensor, and the third circulating pump is activated in response to the signal read from the third temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the third temperature sensor exceeding a fifth predefined temperature, and the third circulating pump is deactivated in response to the signal read from the third temperature sensor being indicative of the temperature of the primary heat exchange medium adjacent the third temperature sensor falling below a sixth predefined temperature.

In one aspect of the invention the fifth predefined temperature lies in the range of 81°C to 86°C, and preferably, lies in the range of 82°C to 85°C, and advantageously, the fifth predefined temperature is approximately 85°C.

In another aspect of the invention the sixth predefined temperature lies in the range of 68°C to 78°C, and preferably, lies in the range of 73°C to 77°C, and advantageously, the sixth predefined temperature is approximately 75°C.

Preferably, the fan of the heat dump heat exchanger is activated and deactivated on activation and deactivation, respectively, of the third circulating pump.

In another aspect of the invention signals are read from the fourth and fifth temperature sensors, and the secondary circulating pump is activated in response to the signals read from the fourth and fifth temperature sensors being indicative of the temperature difference of the temperature of the secondary heat exchange medium adjacent the fifth temperature sensor less the temperature of the primary heat exchange medium adjacent the fourth temperature sensor exceeding a first predefined temperature difference value.

Preferably, the secondary circulating pump is deactivated in response to the difference of the temperature of the secondary heat exchange medium adjacent the fifth temperature sensor less the temperature of the primary heat exchange medium adjacent the fourth temperature sensor falling below a second predefined temperature difference value.

Advantageously, the second predefined temperature difference value does not exceed 2°C. Preferably, the second predefined temperature difference value is at least 1 °C.

Advantageously, the second predefined temperature difference value lies in the range of TC to 3°C. In one aspect of the invention the first predefined temperature difference value is at least 5°C.

Preferably, the first predefined temperature difference value is at least 7°C.

Advantageously, the first predefined temperature difference value lies in the range of 5°C to 9°C. The advantages of the invention are many. A particularly important advantage of the invention is achieved by virtue of the relative locations of the first inlet and outlet ports and the second inlet and outlet ports in the heat exchange vessel. It has been found that by returning the primary heat exchange medium from the heat exchange vessel to the first heat source at a level well above the level at which the primary heat exchange medium is returned from the space heating heat exchange means to the heat exchange vessel, a particularly efficient operation of the heating system is achieved. A further advantage of the invention is achieved by virtue of the fact that the first outlet port from the heat exchange vessel is located at a level above the location of the first heat exchange element in the heat exchange vessel. This leads to further efficiency of the heating system.

Additionally, by returning the primary heat exchange medium to the first heat source from the heat exchange vessel at the level well above the level at which the primary heat exchange medium is returned to the heat exchange vessel from the space heating heat exchange means, and by locating the first heat exchange element in the heat exchange vessel between these two levels, heat transfer from the secondary heat exchange medium to the primary heat exchange medium through the first heat exchange element is particularly efficient, and can be achieved at lower temperatures of the secondary heat exchange medium, which is particularly suitable for solar heated secondary heat exchange medium. A further advantage of returning the primary heat exchange medium from the heat exchange vessel to the first heat source at a level well above the level at which the primary heat exchange medium is returned to the heat exchange vessel from the space heating heat exchange means is that the primary heat exchange medium is returned to the first heat source at a higher temperature than would otherwise be the case, which thereby improves the operating efficiency of the first heat source. Additionally, by locating the first heat exchange element in the lower portion of the heat exchange vessel and supplying the first heat exchange element with the secondary heat exchange medium from the second heat source, when the second heat source is provided as a solar panel, a particularly efficiently operating heating system is provided. A further advantage of the invention is achieved by virtue of the location of the third inlet port in the hollow interior region of the heat exchange vessel through which cooled primary heat exchange medium from the heat dump heat exchanger is returned to the hollow interior region of the heat exchange vessel. It has been found that by locating the third inlet port to communicate with the hollow interior region of the heat exchange vessel at the level between the levels at which the first inlet and outlet ports communicate with the hollow interior region of the heat exchange vessel, only the excessively hot primary heat exchange medium in the upper part of the heat exchange vessel is cooled sufficiently to avoid over-heating of the primary heat exchange medium, without cooling the primary heat exchange medium in the remainder of the heat exchange vessel, thereby avoiding over-cooling of the primary heat exchange medium, and thus providing an efficient heating system.

Additionally, the provision of the heat dump heat exchanger for dumping excess heat from the primary heat exchange medium when it is not required, or cannot be dissipated through the space heating heat exchange circuit allows the total volume of the heat exchange vessel to be minimised, and significantly less than that required for other systems which include a solar panel for providing heat to the primary heat exchange medium.

The invention will be more clearly understood from the following description of a preferred embodiment thereof, which is given by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 illustrates a circuit diagram of a heating system according to the invention, and Fig. 2 illustrates a circuit diagram of the plumbing of the heating system of Fig. 1.

Referring to the drawings, there is illustrated a heating system according to the invention, indicated generally by the reference numeral 1, for providing space heating and domestic hot water. The heating system 1 comprises a heat exchange vessel 3 having a side wall 2 extending upwardly from a base 4 adjacent a lower end thereof to a top wall 5 adjacent an upper end thereof. The side wall 2, the base 4 and the top wall 5 together define an enclosed hollow interior region 7 of the heat exchange vessel 3 for a primary heat exchange medium, which in this embodiment of the invention is a heat exchange liquid heat exchange medium, namely, water. The heat exchange vessel 3 may be of any suitable capacity, and the capacity will largely depend on the heat requirement of the heating system 1. However, typically, the capacity of the heat exchange vessel 3 would be of capacity in the range of 250 litres to 1000 litres, and the heat exchange vessels 3 according to the invention would be supplied in capacities typically in steps of 50 litres. In this embodiment of the invention the side wall 2 of the heat exchange vessel 3 is cylindrical, although the side wall may be of any cross-section in plan view, for example, square cross- section, rectangular cross-section, hexagonal cross-section, octagonal cross-section or any suitable or desired cross-section. While the heat exchange vessel 3 may be of any suitable and desirable dimensions, and the dimensions of the vessel 3 will be dependent on the capacity of the vessel, in this embodiment of the invention the heat exchange vessel 3 is provided in the form of a vertically standing cylinder having a diameter D of approximately 500mm, and a height H of approximately 1,800mm.

Two heat exchange elements, namely, a first heat exchange element provided by a first heat exchange coil 9, and a second heat exchange element provided by a second heat exchange coil 10 are located in the hollow interior region 7 of the heat exchange vessel 3, one above the other, for functions which will be described below. Two first heat sources are provided for heating the primary heat exchange water for the heat exchange vessel 3. The first heat sources may be any suitable heat sources, for example, one or more oil or gas fired boilers, one or more solid fuel boilers and/or one or more back boilers, or any combination of such boilers. In this embodiment of the invention one of the first heat sources comprises an oil fired boiler 12, and the other first heat source comprises a solid fuel burning back boiler 14.

A space heating heat exchange means, namely, a space heating heat exchange circuit 15 is provided with primary heat exchange water from the heat exchange vessel 3 for space heating. In this embodiment of the invention the space heating heat exchange circuit 15 comprises a plurality of space heat exchangers, namely, panel radiators 17 for space heating rooms of a house, office or other such premises. An expansion tank 18 which is supplied from a mains water supply through a ball valve 19 maintains the pressure of the primary heat exchange water within the heating system 1 at a predefined pressure, and receives primary heat exchange water from the heat exchange vessel 3 resulting from expansion of the primary heat exchange water in the heating system 1. However, it will be appreciated that the primary heat exchange water may be pressurised by providing the heating system 1 as a closed pressurised system with a pressurised vessel for maintaining the pressure of the primary heat exchange water at a suitable predefined pressure. Such closed heating systems with a pressurised vessel will be well known to those skilled in the art. A domestic water header tank 20 supplies water to the second heat exchange coil 10 for heating the water from the domestic water header tank to provide domestic hot water.

A second heat source, namely, a solar panel 22 is provided for heating a secondary heat exchange medium, which in this embodiment of the invention is a liquid heat exchange medium, and in this particular embodiment of the invention comprises a low temperature freezing point water/glycol mixture. For convenience hereinafter the secondary heat exchange medium will be referred to as the secondary heat exchange water. The heated secondary heat exchange water is supplied to the first heat exchange coil 9 in the heat exchange vessel 3 for heating the primary heat exchange water in the heat exchange vessel 3 in the lower portion thereof by heat exchange through the first heat exchange coil 9.

A heat dump heat exchanger, which in this embodiment of the invention comprises a fan assisted heat exchanger 24, is provided for dumping excess heat from the primary heat exchange water in the event of over-heating of the primary heat exchange water as will be described in more detail below. Turning now in more detail to the heat exchange vessel 3, the heat exchange vessel 3 comprises two first inlet ports 25a and 25b in the side wall 2 communicating with the hollow interior region 7 thereof for receiving heated primary exchange water from the oil fired boiler 12 and the back boiler 14, respectively. Two first outlet ports 26a and 26b are provided in the side wall 2 of the heat exchange vessel 3 communicating with the hollow interior region 7 thereof for returning primary heat exchange water from the hollow interior region 7 of the heat exchange vessel 3 to the oil fired boiler 12 and the back boiler 14, respectively. The first inlet ports 25 are located in the side wall 2 adjacent the top wall 5 of the heat exchange vessel 3 and communicate with the hollow interior region 7 thereof also adjacent the top wall 5 of the heat exchange vessel 3. The first outlet ports 26 are located in the side wall 2 intermediate the top wall 5 and the base 4 of the heat exchange vessel 3, and communicate with the hollow interior region 7 of the heat exchange vessel 3 at locations intermediate the top wall 5 and the base 4 of the heat exchange vessel 3. In this embodiment of the invention the location at which the first outlet ports 26 communicate with the hollow interior region 7 of the heat exchange vessel 3 is at a level just below midway between the top wall 5 and the base 4 of the heat exchange vessel 3, and between the first and second heat exchange coils 9 and 10, respectively, but closer to the first heat exchange coil 9 than to the second heat exchange coil 10, although it will be appreciated that the level at which the first outlet ports 26 communicate with the hollow interior region 7 of the heat exchange vessel 3 may be at a location midway between the base 4 and the top wall 5 of the heat exchange vessel 3, or indeed, at a level either slightly above midway or slightly below midway between the base 4 and the top wall 5 of the heat exchange vessel 3. A first flow pipe 27 connects a flow outlet port 28 of the oil fired boiler 12 with the first inlet port 25a, while a first return pipe 29 connects the first outlet port 26a with a return inlet port 30 of the oil fired boiler 12. A first flow pipe 31 from a flow outlet port 32 of the back boiler 1 connects the flow outlet port 32 with the first inlet port 25b, while a second return pipe 33 from the first outlet port 26b connects the first outlet port 26b with a return inlet port 34 of the back boiler 14. A first circulating pump 35a is located in the first return pipe 29 between the first outlet port 26a and the return inlet port 30 of the oil fired boiler 12 for circulating the primary heat exchange water between the oil fired boiler 12 and the heat exchange vessel 3. A first circulating pump 35b is located in the first return pipe 33 between the first outlet port 26b and the return inlet port 34 to the back boiler 14 for circulating the primary heat exchange water between the back boiler 14 and the heat exchange vessel 3.

A second outlet port 38 is located in the side wall 2 of the heat exchange vessel 3 adjacent the top wall 5 thereof and communicates with the hollow interior region 7 of the heat exchange vessel 3 adjacent the top wall 5 thereof at a level substantially similar to the level at which the first inlet ports 25 communicate with the hollow interior region 7 of the heat exchange vessel 3. The primary heat exchange water is delivered through the second outlet port 38 to the space heating heat exchange circuit 15. A second inlet port 39 is located in the side wall 2 of the heat exchange vessel 3 adjacent the base 4 thereof, and communicates with the hollow interior region 7 of the heat exchange vessel 3 adjacent the base 4 for receiving returned primary heat exchange water from the space heating heat exchange circuit 15.

A second flow pipe 40 from the second outlet port 38 of the heat exchange vessel 3 delivers the primary heat exchange water from the heat exchange vessel 3 to the space heating heat exchange circuit 15. A second return pipe 41 connected to the second inlet port 39 of the heat exchange vessel 3 returns the primary heat exchange water from the space heating heat exchange circuit 15 to the heat exchange vessel 3. A second circulating pump 43 in the second flow pipe 40 circulates the primary heat exchange water between the heat exchange vessel 3 and the space heating heat exchange circuit 15.

Turning now to the first heat exchange coil 9, the first heat exchange coil 9 is located in a lower portion of the hollow interior region 7 of the heat exchange vessel 3 between the first outlet ports 26 and the second inlet port 39. The first heat exchange coil 9 extends between a secondary inlet port 45 through which the secondary heat exchange water is delivered to the first heat exchange coil 9 from the solar panel 22, and a secondary outlet port 46 through which the secondary heat exchange water is returned from the first heat exchange coil 9 to the solar panel 22. The secondary inlet and outlet ports 45 and 46 sealably extend through the side wall 2 of the heat exchange vessel 3 from the first heat exchange coil 9, so that the secondary heat exchange water is isolated from the primary heat exchange water in the hollow interior region 7 of the heat exchange vessel 3, and heat is transferred through the first heat exchange coil 9 from the secondary heat exchange water to the primary heat exchange water in the heat exchange vessel 3. The secondary outlet port 46 extends through the side wall 2 of the heat exchange vessel 3 at a location downwardly from the location through which the secondary inlet port 45 extends through the side wall 2 of the heat exchange vessel 3. In this embodiment of the invention the secondary outlet port 46 extends through the side wall 2 of the heat exchange vessel 3 at a location slightly spaced apart upwardly from the location at which the second inlet port 39 communicates with the hollow interior region 7 of the heat exchange vessel 3. The secondary inlet port 45 extends through the side wall 2 of the heat exchange vessel 3 at a location slightly spaced apart downwardly from the location at which the first outlet ports 26 communicates with the hollow interior region 7 of the heat exchange vessel 3.

A secondary flow pipe 48 connects a flow outlet port 49 from the solar panel 22 with the secondary inlet port 45 of the first heat exchange coil 9 for accommodating the secondary heat exchange water from the solar panel 22 to the first heat exchange coil 9. A secondary return pipe 50 connects the secondary outlet port 46 with a return port 51 of the solar panel 22 for returning the secondary heat exchange wafer from the first heat exchange coil 9 to the solar panel 22. A secondary circulating pump 52, which in this embodiment of the invention comprises a modulating pump is located in the secondary return pipe 50 for circulating the secondary heat exchange water between the solar panel 22 and the first heat exchange coil 9 in the heat exchange vessel 3.

A third outlet port 55 in the top wall 5 of the heat exchange vessel 3 communicates with the hollow interior region 7 of the heat exchange vessel 3 adjacent the top wall 5 thereof. The primary heat exchange water is delivered through the third outlet port 55 to the heat dump heat exchanger 24. A third inlet port 58 located in the top wall 5 of the heat exchange vessel 3 receives cooled primary heat exchange water from the heat dump heat exchanger 24. A down pipe 57 extends sealably from the third inlet port 58 through the top wall 5 and terminates in an inlet opening 59 through which the cooled primary heat exchange water is returned from the heat dump heat exchanger 24 into the hollow interior region 7 within the second heat exchange coil 10 at a level between the first inlet ports 25 and the first outlet ports 26. In this embodiment of the invention the ratio of the spacing between the location of the inlet opening 59 of the down pipe 57 from the third inlet port 58 and the first outlet ports 26 to the spacing between the location of the inlet opening 59 and the location of the first inlet ports 25 is in the ratio of 2:1 approximately.

A third flow pipe 60 connects the third outlet port 55 with an inlet port 61 of the heat dump heat exchanger 24 through which the primary heat exchange water is delivered from the heat exchange vessel 3 to the heat dump heat exchanger 24. A third return pipe 62 connects an outlet port 63 of the heat dump heat exchanger 24 with the third inlet port 58 through which the cooled primary heat exchange water is returned from the heat dump heat exchanger 24 to the heat exchange vessel 3 through the inlet opening 59 in the down pipe 57. A third circulating pump 65 located in the third flow pipe 60 circulates the primary heat exchange water between the hollow interior region 7 of the heat exchange vessel 3 and the heat dump heat exchanger 24.

Turning now to the second heat exchange coil 10, the second heat exchange coil 10 is located in an upper portion of the hollow interior region 7 of the heat exchange vessel 3 between the first inlet ports 25 and the first outlet ports 26. The second heat exchange coil 10 extends between a water inlet port 68 through which cold water is delivered from the domestic water header tank 20 to the second heat exchange coil 10, and a water outlet port 72 through which heated domestic hot water is supplied from the second heat exchange coil 10. The water inlet and outlet ports 68 and 72 of the second heat exchange coil 10 extend from the heat exchange coil 10 sealably through the side wall 2 of the heat exchange vessel 3 for accommodating the water from the domestic water header tank 20 through the second heat exchange coil 10, so that the water from the domestic water header tank 20 in the second heat exchange coil 10 is isolated from the primary heat exchange water in the hollow interior region 7 of the heat exchange vessel 3, and so that heat is transferred from the primary heat exchange water in the hollow interior region 7 of the heat exchange vessel 3 to the water passing through the second heat exchange coil 10. A cold water supply pipe 70 connects the domestic water header tank 20 with the water inlet port 68 of the second heat exchange coil 10 for delivering water from the domestic water header tank 20 to the second heat exchange coil 10. A hot water supply pipe 73 connected to the water outlet port 72 from the second heat exchange coil 10 delivers domestic hot water from the second heat exchange coil 10 for supply to domestic hot water taps (not shown).

The water outlet port 72 extends through the side wall 2 of the heat exchange vessel 3 at a location spaced apart upwardly from the location at which the water inlet port 68 extends through the side wall 2 of the heat exchange vessel 3. In this embodiment of the invention the water outlet port 72 extends through the side wall 2 of the heat exchange vessel 3 at a level substantially similar to the level at which the first inlet ports 25 communicate with the hollow interior region 7 of the heat exchange vessel 3. In this embodiment of the invention the water inlet port 68 extends through the side wall 2 of the heat exchange vessel 3 at a level spaced apart upwardly from the location at which the first outlet ports 26 communicate with the hollow interior region 7 of the heat exchange vessel 3. Additionally, in this embodiment of the invention the location through which the water inlet port 68 extends through the side wall 2 of the heat exchange vessel 3 is spaced apart downwardly below the level of the inlet opening 59 in the hollow interior region 7 of the heat exchange vessel 3, and the location at which the water outlet port 72 extends through the side wall 2 of the heat exchange vessel 3 is spaced apart upwardly above the level of the inlet opening 59 in the hollow interior region 7 of the heat exchange vessel 3.

A temperature controlled mixing valve 75 is located in the hot water supply pipe 73 and is coupled to the cold water supply pipe 70 by a pipe 76 for mixing cold water from the domestic water header tank 20 with the hot water from the second heat exchange coil 10 for controlling the temperature of the domestic hot water supplied through the hot water supply pipe 73.

A make-up pipe 78 which is tapped into the second return pipe 41 from the space heating heat exchange circuit 15 provides make-up water to the heating system 1 from the expansion tank 18 should it be required, and maintains the pressure of the primary heat exchange water at the predefined pressure, which is defined by the height of the expansion tank 18 above the heat exchange vessel 3. An expansion pipe 79 extending from the top wall 5 of the heat exchange vessel 3 accommodates expansion of the primary heat exchange water from the heat exchange vessel 3 to the expansion tank 18. A drain port 77 extending through the side wall 2 adjacent the base 4 of the heat exchange vessel 3 facilitates draining of the heating system 1. As discussed above, instead of the make-up pipe 78 and the expansion tank 18 and the expansion pipe 79, the primary heat exchange water may be pressurised by providing the heating system 1 as a closed pressurised system with a pressurised vessel.

A control means provided by a control circuit 80 comprises a microcontroller 81 for controlling the operation of the heating system 1 in response to temperatures read from a plurality of temperature sensors, namely, first, second, third, fourth and fifth temperature sensors.

The first temperature sensor 82 is located in the heat exchange vessel 3 at a level above the first outlet ports 26 and between the first inlet and outlet ports 25 and 26. In this embodiment of the invention the first temperature sensor 82 is spaced apart above the first outlet ports 26 a distance which is approximately 12.5% of the distance the first inlet ports 25 are spaced apart above the, first outlet ports 26. The microcontroller 81 is programmed to read signals from the first temperature sensor 82, and is responsive to the signals read from the first temperature sensor 82 being indicative of the temperature of the primary heat exchange water in the heat exchange vessel 3 adjacent the first temperature sensor 82 falling below a first predefined temperature, typically of the order of 57°C, for activating the first circulating pump 35a to circulate the primary heat exchange water between the oil fired boiler 12 and the heat exchange vessel 3. The microcontroller 81 is responsive to the signals read from the first temperature sensor 82 being indicative of the temperature of the primary heat exchange water adjacent the first temperature sensor 82 exceeding a second predefined temperature, typically of the order of 62°C for deactivating the oil fired boiler 12.

If the back boiler 14 is operational, prior to activating the first circulating pump 35a in response to the temperature sensed by the first temperature sensor 82 falling below the first predefined temperature of 57°C, the microcontroller 81 may be programmed to activate the first circulating pump 35b for circulating the primary heat exchange water between the back boiler 14 and the heat exchange vessel 3. If after a predefined time period of not more than ten seconds from activating the first circulating pump 35b the temperature sensed by the first temperature sensor 82 remained below 57°C, the microcontroller 81 would be programmed to activate the first circulating pump 35a for circulating the primary heat exchange water between the oil fired boiler 12 and the heat exchange vessel 3. Additionally, if the back boiler 14 is operational, on the temperature sensed by the first temperature sensor 82 exceeding the second predefined temperature of 62°C, the microcontroller 81 would deactivate first circulating pump 35a, and would maintain the first circulating pump 35b active until the temperature of the primary heat exchange water in the back boiler 14 has reduced to a safe working temperature, in order to avoid a pressure build- up in the back boiler 14. Although not shown, a temperature sensor is provided in the back boiler, and is connected to the microcontroller 81.

The second temperature sensor 84 is located in the heat exchange vessel 3 inside the second heat exchange coil 10 at a level below the first inlet ports 25 for monitoring the temperature of the primary heat exchange water in the upper portion of the hollow interior region 7 of the heat exchange vessel 3 within the second heat exchange coil 10. In this embodiment of the invention the second temperature sensor 84 is located in the heat exchange vessel 3 a distance below the second outlet port 38 which is approximately 12.5% of the distance the first outlet ports 26 are located below the second outlet port 38. The microcontroller 81 is programmed to read signals from the second temperature sensor 84. The microcontroller 81 is responsive to the signals read from the second temperature sensor 84 being indicative of the temperature of the primary heat exchange medium in the heat exchange vessel 3 adjacent the second temperature sensor 84 falling below a third predefined temperature, namely, a temperature of approximately 49°C, for deactivating the second circulating pump 43. The microcontroller 81 is responsive to the signals read from the second temperature sensor 84 being indicative of the temperature of the primary heat exchange water adjacent the second temperature sensor 84 exceeding a fourth predefined temperature of approximately 65°C, for reactivating the second circulating pump 43 for recommencing circulation of the primary heat exchange water from the heat exchange vessel 3 to the space heating heat exchange circuit 15.

The third temperature sensor 88 is located in the heat exchange vessel 3 for monitoring the temperature of the primary heat exchange water between the first inlet ports 25 and the first outlet ports 26 at a level substantially similar to the level of the inlet opening 59 of the down pipe 57. Additionally, the third temperature sensor 88 is located at a level below the second temperature sensor 84. The microcontroller 81 is programmed to read signals from the third temperature sensor 88. The microcontroller 81 is responsive to the signals read from the third temperature sensor 88 being indicative of the temperature of the primary heat exchange water adjacent the third temperature sensor 88 exceeding a fifth predefined temperature, in this case 85°C, for activating the third circulating pump 65 and the fan of the heat dump heat exchanger 24 for circulating the primary heat exchange water between the heat exchange vessel 3 and the heat dump heat exchanger 24 for cooling of the primary heat exchange water. The microcontroller 81 is responsive to the signal read from the third temperature sensor 88 being indicative of the temperature of the primary heat exchange water adjacent the third temperature sensor 88 falling below a sixth predefined temperature, in this case 75°C, for deactivating the third circulating pump 65 and the fan of the heat dump heat exchanger 24.

A fourth temperature sensor 85 is located in the heat exchange vessel 3 substantially midway between the first outlet ports 26 and the second inlet port 39 for monitoring the temperature of the primary heat exchange water in the heat exchange vessel 3 adjacent the third temperature sensor 85, and also midway between the secondary inlet and outlet ports 45 and 46 of the first heat exchange coil 9. A fifth temperature sensor 86 is located in the solar panel 22 for monitoring the temperature of the secondary heat exchange water in the solar panel 22 adjacent the outlet port 49 from the solar panel 22. The microcontroller 81 is programmed to read signals from the fourth and fifth temperature sensors 85 and 86, respectively, which are indicative of the temperatures of the primary heat exchange water adjacent the fourth temperature sensor 85, and the secondary heat exchange water adjacent the fifth temperature sensor 86, respectively. The microcontroller 81 is programmed to subtract the temperature read from the fourth temperature sensor 85 from the temperature read from the fifth temperature sensor 86. On the difference in the temperatures sensed by the fourth temperature sensor 85 and the fifth temperature sensor 86 exceeding a first predefined temperature difference value, in this case of 7°C, the microcontroller 81 activates the secondary circulating pump 52 for circulating the secondary heat exchange water between the solar panel 22 and the heat exchange vessel 3. On the difference in the temperature between the fourth temperature sensor 85 and the fifth temperature sensor 86 falling below a second predefined temperature difference value, in this case of 2°C, the microcontroller 81 deactivates the secondary circulating pump 52.

In use, with the heat exchange system 1 fully installed, the oil fired boiler 12 is powered up to supply heat to the heating system 1. The first circulating pump 35a is operated under the control of the microcontroller 81 to circulate primary heat exchange medium between the oil fired boiler 12 and the heat exchange vessel 3. The microcontroller 81 maintains the first circulating pump 35a activated until the temperature read from the first temperature sensor 82 exceeds the second predefined temperature of 62°C. On the temperature read from the first temperature sensor 82 exceeding the second predefined temperature of 62°C, the microcontroller 81 deactivates the first circulating pumps 35a. On the temperature read from the first temperature sensor 82 falling below the first predefined temperature of 57°C, the microcontroller 81 reactivates the first circulating pumps 35a, and maintains the first circulating pump 35a activated until the temperature read from the first temperature sensor 82 again exceeds the second predefined temperature of 62°C, and so on. On the temperature read from the second temperature sensor 84 rising above the fourth predefined temperature of 65°C, the microcontroller 81 activates the second circulating pump 43 for circulation the primary heat exchange medium between the heat exchange vessel 3 and the space heating heat exchange circuit 15. On the temperature read from the second temperature sensor 84 falling below the third predefined temperature of 49°C, the microcontroller 81 deactivates the second circulating pump 43, and maintains the second circulating pump 43 deactivated until the temperature read from the second temperature sensor 84 rises above the fourth predefined temperature of 65°C, at which stage the second circulating pump 43 is reactivated, and so on.

While the temperature difference between the fourth and fifth temperature sensors 85 and 86 exceeds the first predefined temperature difference value of 7°C, the microcontroller 81 maintains the secondary circulating pump 52 activated for circulating the secondary heat transfer water between the solar panel 22 and the first heat exchange coil 9. On the microcontroller 81 detecting that the temperature difference between the temperatures read from the fourth and fifth temperature sensors 85 and 86 has dropped below the second predefined temperature difference value of approximately 2°C, the microcontroller 81 deactivates the secondary circulating pump 52 and retains the secondary circulating pump 52 deactivated until the temperature difference between the fourth and fifth temperature sensors 85 and 86 again exceeds the first predefined temperature difference value of 7°C, at which stage the secondary circulating pump 52 is reactivated, and so on.

On the microcontroller 81 determining that the signals read from the third temperature sensor 88 are indicative of the temperature of the primary heat exchange water adjacent the third temperature sensor 88 exceeding the fifth predefined temperature of approximately 85°C, in order to avoid overheating of the primary heat exchange water in the heat exchange vessel 3, which could occur on a hot, sunny summer day as a result of heat transferred into the primary heat exchange water from the secondary heat exchange water through the first heat exchange coil 9, the microcontroller 81 activates the third circulating pump 65 for circulating the primary heat exchange water between the heat exchange vessel 3 and the heat dump heat exchanger 24, and also operates the fan of the heat dump heat exchanger 24. The microcontroller 81 maintains the third circulating pump 65 active until the temperature of the primary heat exchange medium read from the third temperature sensor 88 falls below the sixth predefined temperature of approximately 75°C.

Domestic hot water is drawn off from the domestic hot water supply pipe 73 as required,

Although not illustrated, it is envisaged that a temperature controlled mixing valve may be provided for mixing return primary heat exchange water to one or both of the active one of the boilers 12 and 14, as the case may be, with flow primary heat exchange water from the second outlet port 38 to the space heating heat exchange circuit 15. The mixing of the return primary heat exchange water from one or both of the boilers with the flow primary heat exchange water to the space heating heat exchange circuit 15 would typically be carried out in a temperature controlled mixing valve which would be somewhat similar to the temperature control mixing valve 75.

While the heat exchange vessel has been described as comprising two first inlet ports and two first outlet ports, any number of first inlet and outlet ports from one upwards may be provided. Typically, a pair of inlet and outlet ports will be provided for each first heat source, although it will be appreciated that a number of heat sources could be connected to the heat exchange vessel through a . single pair of first inlet and outlet ports by using appropriate inlet and outlet manifolds. While a single space heating heat exchange circuit 15 has been described, it will be readily apparent to those skilled in the art that any number of space heating heat exchange circuits 15 may be provided, and it will also be appreciated that each space heating heat exchange circuit will be provided with its own second circulating pump.

Needless to say, it will be appreciated that while only one pair of second inlet and outlet ports have been described, any number of second inlet and outlet ports may be provided. Typically, a pair of second inlet and outlet ports will be provided for each space heating heat exchange circuit, although it will be readily apparent by those skilled in the art that a number of space heating heat exchange circuits may be connected to the heat exchange vessel by a single pair of second inlet and outlet ports by using appropriate inlet and outlet manifolds.

While the heating system has been described as being pressurised by an expansion tank, while this is desirable, it is not essential. Other suitable pressurised means may be provided for pressurising the heating system.

While the microcontroller has been described as being responsive to specific predefined temperature values read from the first to the fifth temperature sensors, it will be appreciated by those skilled in the art that the values of the predefined temperatures and the predefined temperature difference values to which the microcontroller is responsive for activating the various circulating pumps may be any suitable predefined temperatures and predefined temperature difference values within respective corresponding temperature ranges. Indeed, in certain cases the temperature values of the respective temperature ranges may vary between plus and/or minus 5°C to 10°C of the ideal predefined values described.

While the control circuit has been described as comprising a microcontroller, any other suitable control means, for example, a signal and/or data processor or signal and/or data processing circuit may be provided. While the space heating heat exchange means has been described as comprising a space heating heat exchange circuit comprising a plurality of space heating heat exchange radiators, it will be readily apparent to those skilled in the art that any other suitable space heating heat exchange means may be provided, for example, an underfloor heat exchanger. Indeed, in certain cases, the space heating heat exchange means may comprise an air heating system whereby a heat exchanger would be provided to transfer heat from the primary heat exchange water to air which typically, would be circulated through an air ducting system. Needless to say, the space heating heat exchange means may comprise any combination of two or more of such space heating heat exchange means.

It will be appreciated that while the heating system has been described as comprising a particular type of heat dump heat exchanger, any other suitable heat dump heat exchanger may be provided, and indeed, in certain cases, it is envisaged that a heat dump heat exchanger may be omitted. While the heat exchange vessel has been described as being of a particular size and range of such sizes, it will be readily apparent to those skilled in the art that the heat exchange vessel may be of any suitable or desired shape and/or size.