The object of the invention is a lower heat source system for a compressor heat pump assembly, enabling coverage of the heat load of individual residential premises in a multi-family building for the purposes of central heating and domestic hot water preparation. The invention relates to the field of heating.

From the European Patent Description EP2322880 B1 , a system is known, comprising a brine circuit combining one or more heat sources constituting a lower heat source for multiple heat pump circuits. A common lower source circuit supplies multiple evaporator units of individual heat pumps. The condenser of each heat pump supplies heat to corresponding heating circuits. The lower heat source for the system is, among others: a heat recovery circuit of an air-brine exchanger from the external air or a heat recovery system from exhaust ventilation air or a solar collector circuit.

From the German Utility Model DE202009007774 U1 , a heat pump system is known, with direct and indirect evaporation, supplied by one or more heat sources. The lower heat source for the system is, among others: heat recovery form the external air realised by a fin exchanger or heat recovery from exhaust ventilation air or solar collectors. The circuits of the lower sources are connected by a collector to a common exchanger constituting the evaporator of the main heat pump system. In the second disclosed variant, multiple exchangers-evaporators of the lower heat sources are connected by a collector to a common main heat pump system. The heat pump supplies heat for the heat distribution and domestic hot water systems.

From European Patent Description EP3770514 B1, a reversible heat pump system with multiple heat sources is known, comprising a secondary and a primary circuit. The system comprises exchangers of the heat pump system operating as an evaporator or a condenser depending on the mode realised by the system. As the lower sources, a heat recovery circuit from the atmospheric air and geothermal energy sources are included in the system.

In accordance with the regulation of the Minister of Infrastructure of Poland, since January 1 , 2021 , the Technical Conditions apply, specifying, by means of the primary energy index Ep [kWh/m ² year], the permissible degree of coverage of the building's heat load due to central heating and preparation of domestic hot water using non-renewable energy carriers. For single-family buildings, the value of the index Ep < 70 [kWh/m ² year], and for multi-family buildings, the value of the index Ep < 65 [kWh/m ² year]. Achieving the value of the index Ep at the assumed normative level is very difficult, especially in case of multi-family buildings. Putting such buildings into operation, in the absence of the possibility of supplying them with district heat, requires huge capital expenditures for converters of renewable energy carriers (solar heating installations, photovoltaic installations) supporting the central heating (CH) installation and preparation of domestic hot water (DHW) based on a non-renewable energy carrier, e.g. natural gas or oil. In order to meet the requirements for reducing the consumption of non-renewable energy carriers, among others, systems using heat pumps are used. The main operational problem of systems based on heat pumps as a heat source is ensuring the required flow of the fluid through the evaporators of individual heat pumps supplying heat to the individual receivers. The flow of the medium through the heat pump evaporator depends on the current heat load of the condenser. The load of the condenser of each heat pump depends on the current heat load of a given receiver. Due to different operating conditions, the heat loads of the condensers and thus the heat loads of the evaporators are different. For this reason, the flow of the medium through the evaporators of individual heat pumps should be different and adjusted to the current heat load of the evaporator. In the structural solutions in the state of the art, due to the necessity of adjusting the flow of the working medium in the installation of the lower source of the heat pump, buffer tank deregulation of the lower source installation may occur, which in turn will reduce the efficiency of the heat pump and increase electricity consumption. A significant problem in the existing heat pump systems with multiple lower heat sources is buffer tank connection of the circuits in a way that does not ensure proper and uniform distribution of the heat carrier from the lower heat source to the evaporators of individual heat pumps.

The object of the solution according to the present invention is providing a lower heat source system for a compressor heat pump assembly, enabling coverage of the heat load of a building for the purposes of central heating and domestic hot water preparation, especially for a multi-family residential building. The application of the solution according to the invention makes it possible to individually supply heat to individual residential premises and to cover the total energy load while ensuring high efficiency and energy efficiency of the heat source system. The solution according to the present invention enables buffer tank balancing of the lower heat source installation, regardless of the current heat load of the condensers of individual heat pumps.

The object of the invention is a lower heat source system for a compressor heat pump assembly comprising a main circuit of an external heat source connected to at least one external heat source, characterised in that the main circuit comprises a primary circuit and a secondary circuit separated with a hydraulic tank, wherein the primary circuit includes an air heat exchanger circuit equipped with a circulation pump, which is connected to the hydraulic tank, where the hydraulic tank is connected on the secondary circuit side to a manifold assembly, and at least one riser is connected to the manifold assembly, wherein each riser is equipped with at least one circulation pump, wherein each riser is connected to an evaporator of the compressor heat pump connected in the thermodynamic circuit to a condenser.

Preferably, the system is characterised in that the primary and secondary circuits are filled with a heat carrier, which is an antifreeze fluid.

Preferably, the system is characterised in that each condenser of the compressor heat pump is connected to an individual circuit of a domestic hot water installation and/or to a central heating installation.

Preferably, the system is characterised in that it comprises an additional external heat source in a form of at least one heat recovery exchanger from exhaust air from mechanical ventilation, wherein each of the heat recovery exchangers is connected to at least one secondary circuit riser using a bypass of the first three-way diverter valve, where the through port of the first three-way diverter valve is connected to the evaporator of the compressor heat pump. Preferably, the system is characterised in that the first three-way diverter valve is an automatic valve that enables changing the flow direction of the medium through the heat recovery exchanger or through the evaporator of the compressor heat pump.

Preferably, the system is characterised in that the air heat exchanger is additionally supplied by a duct with exhaust air from mechanical ventilation or mechanical ventilation with heat recovery.

Preferably, the system is characterised in that it comprises an additional external heat source in a form of an additional air heat exchanger included downstream of the air heat exchanger in the primary circuit.

Preferably, the system is characterised in that the additional air heat exchanger is supplied by a duct with exhaust air from mechanical ventilation or mechanical ventilation with heat recovery.

Preferably, the system is characterised in that it comprises an additional external heat source in a form of an additional solar collector circuit which is connected to the hydraulic tank, wherein the collector circuit is equipped with a solar circulation pump, and an additional heat exchanger is connected to the secondary circuit of at least one riser, constituting a bypass of the supply medium of each compressor heat pump, wherein the exchanger circuit is connected to at least one riser through a bypass of the second three-way diverter valve supplying the domestic hot water installation circuit through a bypass of the third three-way diverter valve.

Preferably, the system is characterised in that the second and third three-way diverter valves are automatic-valves that enable changing the flow direction of the medium through the additional heat exchanger or directly through the evaporator of the compressor heat pump.

Preferably, the system is characterised in that an external heat exchanger, constituting a reversible condenser in the cooling mode, is included in at least one thermodynamic circuit on the high pressure side of the compressor heat pump.

Preferably, the system is characterised in that the hydraulic tank constitutes a fluid coupling or a buffer tank.

The application of the solution according to the invention enables individual supply of heat generated by the heat pumps to individual residential premises, which allows individual billing of users for consumed electricity necessary to power the compressor heat pump. Buffer tank connection of the circuits in a manner according to the invention ensures appropriate and uniform distribution of the fluid from the lower heat source to the evaporators of individual heat pumps. The solution according to the invention makes it possible to cover the entire energy load of the building with one energy carrier, i.e. electricity. Additionally, the invention allows using a compressor heat pump operating in a buffer tank installation, which covers the heat loads of individual residential premises in a multi-family building for central heating, domestic hot water and air-conditioning. The solution enables supplying one residential premises from one heat pump, which allows individual billing of the users of individual premises for the electricity consumed by the heat pump. The system according to the invention can operate as a monovalent installation, or in a hybrid system, and be supported by a solar heating system or waste heat from a mechanical ventilation installation. The solution enables utilisation of waste heat and/or the inclusion of additional heat sources supporting the operation of the buffer tank installation constituting the lower heat source of compressor heat pumps, thus forming a hybrid energy system. By using additional lower heat sources, it is possible to further increase the efficiency of heat pumps by increasing the temperature of the lower source necessary to evaporate the refrigerant, which in turn reduces the value of the EP index. The solution according to the invention makes it possible to cover the heat load of a single flat for the purposes of central heating and domestic hot water preparation, as well as the demand for cooling in the summer period. Adjusting the efficiency of the heat pump supplying a single flat to the current requirements of the user makes it possible to ensure thermal comfort and reduce electricity consumption, which positively translates into electricity reduction. The solution according to the invention allows individual adjustment of the flow of antifreeze fluid through the evaporators of heat pumps based on the current load. According to one of the preferred embodiments, it is possible to temporarily shut down the compressor heat pumps, which in turn reduces the operating costs of the installation and extends the service life of the compressors. The solution, by using an air heat exchanger, makes it possible to protect against an excessively high temperature level of the fluid, especially in the summer period in case of no heat reception in the domestic hot water installation. The result of the above-mentioned set of technical features of the invention is a solution that ensures appropriate and uniform distribution of the fluid from the lower heat source to the evaporators of individual heat pumps in order to ensure adequate energy efficiency of the system.

According to the present invention, the riser is a pair of pipelines, where one pipeline is a heat carrier supply to the evaporator of the heat pump, and the other pipeline is the return of the heat carrier from the evaporator of the heat pump. According to the present invention, the manifold assembly is a pair constituting a manifold of the return circuit and the supply circuit of the evaporator of the heat pump.

The object of the invention in the embodiments is shown in the drawing, in which: fig. 1 shows a lower heat source system for a compressor heat pump assembly comprising a main circuit of an external heat source, in which the lower heat source is the atmospheric air, fig. 2 shows a lower heat source system for a compressor heat pump assembly equipped with an additional external heat source in a form of a heat recovery exchanger from exhaust air from mechanical ventilation, fig. 3 shows a lower heat source system for a compressor heat pump assembly, in which the air heat exchanger of the main system of the lower heat source is supplied with exhaust air from mechanical ventilation or mechanical ventilation with heat recovery, fig. 4 shows a lower heat source system for a compressor heat pump assembly equipped with an additional air heat exchanger supplied with exhaust air from ventilation, fig. 5 shows a lower heat source system for a compressor heat pump assembly equipped with an additional external heat source in a form of a solar collector circuit, and fig. 6 shows a lower heat source system for a compressor heat pump assembly, in which the thermodynamic circuit of the heat pump is equipped with an external heat exchanger being a reversible evaporator in a cooling mode.

Example 1 A lower heat source system for a compressor heat pump assembly comprising a main circuit of an external heat source connected to at least one external heat source. This system includes a main circuit comprising a primary circuit and a secondary circuit separated with a hydraulic tank 2, wherein the primary circuit includes a circuit of an air heat exchanger 1 equipped with a circulation pump 3, which is connected to the hydraulic tank 2. Where the hydraulic tank 2 is connected to a manifold assembly 4 on the side of the secondary circuit. At least one riser 6 is connected to the manifold assembly, wherein each riser 6 is equipped with at least one circulation pump 7, wherein the riser 6 is connected to an evaporator 5a of the compressor heat pump 5 connected in a thermodynamic circuit to a condenser 5b. In the primary and secondary circuits, an antifreeze fluid is used as a heat carrier. The hydraulic tank 2 constitutes a fluid coupling or a buffer tank. The condensers 5b of the compressor heat pumps 5 are connected to the individual circuits of the domestic hot water installation 8 and/or a central heating installation 9.

The heat is obtained from the atmospheric air by means of an air heat exchanger 1. The flow through the air heat exchanger 1 is forced by means of fans. The obtained heat is transferred in the exchanger 1 to the antifreeze fluid being the heat carrier in the circuit supplying the evaporators 5a of individual heat pumps 5. The fluid flow through the air heat exchanger 1 is forced by means of a circulation pump 3. The fluid flow in individual risers 6 supplying the evaporators 5a of individual heat pumps 5 is forced by means of circulation pumps 7, which are connected to the manifold assembly 4. The fluid flow is individually adjusted based on the current load, and individual activation of each heat pump 5 occurs based on the set value of temperature in individual circuits of the domestic hot water installation 8 and the central heating installation 9. (fig. 1)

Example 2

Lower heat source system is analogical to that in Example 1 except that:

The system is equipped with an additional external heat source, which is an at least one heat recovery exchanger 10 from the exhaust air from mechanical ventilation, wherein each of the heat recovery exchangers 10 is connected to at least one secondary circuit riser 6 using a bypass of the first three- way diverter valve 11 , where the through port of said valve is connected directly to the evaporator 5a of the compressor heat pump 5. The system is equipped with the first three-way diverter valve 11 which is an automatic valve that enables changing the flow direction of the medium through the heat recovery exchanger 10 or directly through the evaporator 5a of the compressor heat pump 5.

If the temperature of exhaust air from the ventilation system is higher than the temperature of atmospheric air constituting the main lower heat source for the compressor heat pumps 5, and the temperature of exhaust air is higher than the temperature of the antifreeze fluid, the first three-way diverter valve 11 is switched to a position which enables the flow of antifreeze fluid through the heat recovery exchanger 10 installed in the exhaust duct of mechanical ventilation. The lower heat source is supported by increasing the temperature of the antifreeze fluid supplying the evaporator 5a of the compressor heat pump 5 by the flow of fluid through the heat recovery exchanger 10. As a result of heat exchange in the heat recovery exchanger 10 between the fluid and the exhaust air, the temperature level of the fluid relative to the temperature of atmospheric air is rising, which increases the evaporation temperature of the refrigerant, (fig. 2)

Example 3

Lower heat source system is analogical to that in Example 1 except that:

The air heat exchanger 1 is additionally supplied by a duct 19 with exhaust air from mechanical ventilation or mechanical ventilation with heat recovery, (fig. 3)

Example 4

Lower heat source system is analogical to that in Example 1 except that:

The system is equipped with an additional external heat source which is an additional air heat exchanger 12, which is included downstream of the air heat exchanger 1 in the primary circuit. The additional air heat exchanger 12 is supplied by a duct 19 with exhaust air from mechanical ventilation or mechanical ventilation with heat recovery, (fig. 4)

Example 5

Lower heat source system is analogical to that in Example 1 except that:

The system is equipped with an additional external heat source, which is a solar collector circuit 13 connected to the hydraulic tank 2, wherein the collector circuit is equipped with a solar circulation pump 17. The hydraulic tank 2 constitutes a buffer tank. An additional heat exchanger 14 is connected to the secondary circuit of at least one riser 6, constituting a bypass of the supply medium of each compressor heat pump 5, wherein said exchanger circuit is connected to at least one riser 6 through a bypass of the second three-way diverter valve 15 and supplies the domestic hot water installation circuit 8 through a bypass of the third three-way diverter valve 16. The second and third three-way diverter valves 15, 16 are automatic valves that enable changing the flow direction of the medium through the additional heat exchanger 14 or directly through the evaporator 5a of the compressor heat pump 5.

The fluid in the solar collector circuit is an antifreeze fluid, the flow of which through the solar collector circuit 13 is forced by means of the solar circulation pump 17. Depending on the current weather conditions, the hydraulic tank 2 can be supplied by means of the solar collector circuit 13 or the air heat exchanger 1. In the summer period, the solar collector circuit 13 can be used directly to supply the domestic hot water installation 8. Three-way diverter valves 15, 16 and the additional heat exchanger 14 allow periodic shutdown of compressor heat pumps 5. The air heat exchanger 1 , due to the airflow forced by the fans, allows lowering the temperature value of the antifreeze fluid in the lower heat source system, protecting against an excessively high temperature level of the fluid, (fig. 5).

Example 6

Lower heat source system is analogical to that in Example 1 except that:

An external heat exchanger 18, constituting a reversible condenser in the cooling mode, is included in at least one thermodynamic circuit on the high pressure side of the compressor heat pump. The system realises a function of active cooling, which is realised by a possible use of a reversible heat pump and connecting it on the high pressure side to an external heat exchanger 18 installed outside the building, the function of which is to dissipate heat from the residential premises to the environment. In the summer period, when lowering the temperature inside the residential premises is required, the compressor heat pump 5 is switched into the reversible operating mode, and the external heat exchanger 18 functions as a condenser for the heat pump 5. The reversible operating mode of the compressor heat pump 5 and connection of the external heat exchanger 18 to the cooling system are realised by means of executive elements integrated into the structure of the heat pump 5. (fig. 6)

List of indications:

1 - air heat exchanger,

2 - hydraulic tank,

3 - circulation pump,

4 - manifold assembly,

5 - compressor heat pump,

5a - evaporator of the heat pump,

5b - condenser of the heat pump,

6 - riser,

7 - individual circulation pump,

8 - domestic hot water installation,

9 - central heating installation,

10 - heat recovery exchanger,

11 - first three-way diverter valve,

12 - additional air heat exchanger,

13 - solar collector installation,

14 - additional heat exchanger,

15 - second three-way diverter valve,

16 - third three-way diverter valve,

17 - solar pump,

18 - external heat exchanger,

19 - duct of the mechanical ventilation or the mechanical ventilation with heat recovery.