The present invention relates to a heat buffer for use in a cold and heat storage system. The invention also relates to a building provided with a cold and heat storage system and a heat buffer.

In cold and heat storage systems heat, or conversely cold, is stored for instance in the ground and then recovered at a later stage. Cold can for instance be extracted from the storage system during the summer period for the purpose of cooling the building, while pre-stored heat can be extracted from the system during winter in order to heat a building.

It is possible to distinguish between open storage systems, wherein heat and/or cold are stored in groundwater via a heat exchanger, and closed systems wherein the transfer takes place via a heat transfer agent such as an antifreeze agent, for instance a glycol solution, which is incorporated in a closed system.

Although such systems provide advantages in respect of energy-saving, the installation costs for such a system are often high. The drilling(s) for reaching the groundwater as heat buffer are a particularly costly step here. Closed systems are known wherein a heat buffer is used which comprises a closed container for a liquid, such as water, through which a heat exchanger for the heat transfer agent is carried. Such a heat exchanger can for instance be embodied as a pipe system, wherein heat is transferred between the heat transfer agent and the liquid at the walls of the pipe. These systems have the drawback however that they are of complex construction, wherein a heat exchanger embodied as pipe system is particularly expensive. An additional problem of these systems is the ice formation on the heat exchanger in the container, so that the heat transfer between the heat transfer agent and the liquid held in the container is not optimal.

The present invention therefore has for its object, among others, to provide a simpler and/or more efficient heat buffer which can be installed at lower cost in a building and/or which can at least partially obviate the above stated problems.

Provided for this purpose according to the invention is a heat buffer for use in a cold and heat storage system, comprising a first container for holding a liquid, particularly water, for storing heat and a second container provided with an infeed and an outfeed for feed of a heat transfer agent through the second container, wherein the first container and the second container comprise a common wall for transferring heat between the first and the second container, wherein the common wall is manufactured from a flexible material. It is advantageous here that, when ice formation occurs on the flexible wall, this ice can be released from the wall by means of moving the wall. The wall can for instance be moved by introducing a surge of heat transfer agent into the second container. The flexible wall preferably extends for this purpose on the underside of the first container so that, after being released, the ice will automatically float to the top, and thereby out of reach of the flexible wall.

A common wall is understood to mean that this wall lies between two containers and is in contact with the content of these containers. It is for instance possible for the flexible wall to comprise the outer wall of the second container, wherein the second container is received in the first container.

The common wall is preferably manufactured from a textile which is impermeable to the liquid and the heat transfer agent. This results in a durable assembly. The textile can be provided for this purpose with a rubber or plastic coating.

The common wall is more preferably manufactured from an elastic material. This makes it possible to compensate for fluctuations in the content of the containers, for instance when a surge, i.e. a temporarily larger quantity, of heat transfer agent is fed into the second container for the purpose of releasing ice from the wall.

According to a preferred embodiment, the first and/or the second container is embodied as a flexible bag, wherein the common wall comprises a wall of the flexible bag. This results in a compact and simple assembly , while a good heat transfer is also provided via the common wall. The bag, or both bags, is/are preferably manufactured from the coated textile. It is moreover advantageous here for the bag or bags to have an elastic character so as to compensate for fluctuations in the content of the containers in the form of bags.

Such a heat buffer is easily arranged in for instance a cellar of a building so that expensive ground drilling is not necessary. The flexible all between the two containers moreover provides for an efficient heat transfer, so that it is possible in the case of a bag-like second container to dispense with a complicated, and thereby costly tube heat exchanger.

In practical manner the second container or bag is the lower of the two containers or bags. This provides a simple system in which released ice is displaced upward and will therefore float out of reach of the flexible wall between the two containers or bags. A particularly simple assembly is achieved when the heat buffer comprises a flexible bag provided with a flexible partition which forms the first and the second container in the bag. The heat buffer is formed here by a flexible bag divided into compartments, wherein the compartments form the first and the second container.

A particularly efficient assembly is however obtained when the second container embodied as bag is received in the first container embodied as bag. The second container, through which the heat transfer agent is carried, is then wholly received in the first container so that a large part of the wall of the second container is in contact with the liquid in the first container. The liquid in the first container is then held between the walls of the first container and the second container. The surface area for heat transfer is therefore exceptionally large, so that an efficient exchange takes place.

In order to make the infeed and the outfeed of the second container accessible for connection to the storage system, the infeed and outfeed of the second container preferably extend through the wall of the first container. This wall of the first container here forms the outer wall of the heat exchanger. It is advantageous here for the walls of the first container and the second container to coincide over an area so that a connection between the two containers can be made here. The infeed and outfeed can for instance be arranged in this connection. The connection can for instance comprise a plate-like element which clampingly receives the walls of the containers. Suitable passages for the infeeds and outfeeds are then arranged in the plate-like element.

In order to enable simple placing of the heat buffer in for instance a cellar of a building, the heat buffer according to a further preferred embodiment has a height which is smaller than the length and w idth of the heat buffer. The height is for this purpose preferably less than 75 centimetres, preferably about 60 centimetres.

In order to provide a good exchange of heat or cold between the two containers it is advantageous for the flow of heat transfer agent to be carried from the infeed to the outfeed along the largest possible part of the common wall. The infeed and the outfeed can for this purpose extend on either side of the second container.

According to a further preferred embodiment, guide means are arranged in the second container for guiding the flow of heat transfer agent from the infeed to the outfeed along at least substantially the whole length or width, or preferably substantially the whole surface area, of the common wall. The guide means are configured to guide or control the heat transfer agent in the second container for the purpose of obtaining an efficient flow for good heat exchange.

The guide means preferably comprise at least one wall or baffle in the second container, which at least one wall or baffle defines with the second container channels for guiding the heat transfer agent. The walls or baffles partially limit the throughflow here such that the heat transfer agent is forced to flow along the surface for the purpose of heat exchange.

The at least one wall or baffle extends for instance from the infeed, which can be disposed on a first side of the second container, to a position close to a second, opposite side of the second container so that the heat transfer agent flows from the first side to the second side of the container in the channel defined by the wall or baffle Because the wall or baffle does not extend as far as the second side, the heat transfer agent can flow around the end of the wall or baffle in an opening created therebetween and flow back from the second side to the first side in a second defined channel. The outfeed can also be disposed on the first side here so that the heat transfer agent can flow out of the second channel. The heat transfer agent flows here through substantially the whole length or width of the common wall, depending on whether the at least one wall or baffle is disposed in the longitudinal or transverse direction of the second container.

If desired, a number of pairs of infeeds and outfeeds can be provided, wherein a wall or baffle is disposed in each case between a pair of infeeds and outfeeds. A pair of two channels is in this way provided in each case.

Alternatively, the container can for instance comprise one infeed and outfeed and two rows of walls which are arranged offset relative to each other for the purpose of creating a meandering flow therebetween. The walls preferably extend parallel and offset relative to each other. The walls are then connected alternately to the first or the second side of the second container such that the openings on the other side of the container form the offset passages for the heat transfer agent.

The at least one wall or baffle preferably has a height corresponding to the height of the second container and a length smaller than the length of the second container, so that the heat transfer agent can turn or meander round the end of the wall or baffle.

The guide means can be formed by connecting zones between an upper and underside of the second container, wherein channels are defined between the connecting zones for the purpose of guiding the heat transfer agent. The connecting zones can for instance be formed by mutually connecting the upper and underside, for instance by means of fusing or glueing. According to a further preferred embodiment, the heat buffer comprises a membrane arranged on a wall of the first container, wherein the second container is formed between the wall of the first container and the membrane. The second container is formed here by a bag which is formed by a wall of the first container and the membrane arranged thereon. The first container formed as a bag and second container formed as a bag have in this embodiment one common wall, i.e. particularly the lower wall. The membrane is preferably connected at the edges, for instance by fusing, to the wall of the first container so that a bag is formed therebetween. The infeed and outfeed are preferably located at the edges of the membrane.

The membrane can comprise a number of further connections, for instance at least one. to the wall of the first container, which also forms the low er wall of the second container, which further connections form the connecting zones of the guide means. The connections can extend here in the direction between the first side and the second w hile in each case leaving clear said opening for reversing or meandering of the flow.

In an embodiment of the heat buffer according to the invention there can be arranged below the underside thereof at least one elongate, upright element which presses the underside of the second container, embodied for instance as a bag, upward in the direction of the upper side of the second container embodied for instance as a bag. Such an elongate, upright element effectively reduces the overall volume of the second container, while the surface area of the second container which is in contact with the first container for the purpose of heat transfer therebetween can remain substantially the same. Relatively less heat transfer agent need be provided as a result. The at least one element can for instance be disposed parallel to the guide means.

The invention also relates to an assembly of a heat buffer according to any of the claims and at least one elongate, upright element arranged thereunder.

It is moreover possible for the infeed and outfeed to be located in the centre of the second container, wherein the infeed and die outfeed face a ay from the centre in opposite directions. The infeed and the outfeed are arranged close together here so that connection to a storage system is simple. It is particularly advantageous for the infeed and outfeed to be located close to the bottom of the second container, and thereby more preferably the underside of the heat buffer. The second container is located here at the bottom of the heat buffer so that the detached ice can float upward in the first container lying above the second container. The infeed and outfeed preferably extend here through the bottom of the heat buffer for connection to a feed and discharge of the storage system of the building.

In order to enable efficient filling of the first container on site the first container preferably comprises an in feed for filling the first container with the liquid. A particularly efficient assembly is then achieved when the infeed of the first container also extends through the bottom of the heat buffer close to the centre. All connections for the heat buffer are then situated close to each other so that connection of the heat buffer in a building is simple. A venting can moreover be provided for a more efficient filling. This preferably extends on the upper side of the first container. The invention also relates to a folded-up and/or rolled-up heat buffer according to the invention. The containers embodied as flexible bags can be rolled up so that they can be arranged in simple manner in for instance a cellar or a crawl space without the floor having to be taken up. Such a heat buffer is moreover easy to transport. The invention further relates to a switching system for a heat storage system for a heat buffer according to the invention for the purpose of switching a heat transfer agent between different systems in the heat storage system, comprising:

an infeed and an outfeed for a heat supply system, for instance a solar collector system and/or a heat exchanger system:

- an infeed and an outfeed for a heat buffer, in particular a heat buffer according to at least one of the claims;

an infeed and an outfeed for a heat take-off system, for instance a heating system;

at least one recirculation pump for circulating the heat transfer agent through a conduit system which connects the different systems in the heat storage system; and

- at least one switch, for instance a valve, for connecting and disconnecting at least one of the above stated systems to and from the heat storage system.

Using such a switching system an existing building with pre-existing infrastructure for for instance the heat take-off system, in particular a system with a heat pump, can be provided in efficient manner with a heat storage system. The conduits are easily connected to the switching system, wherein switching between the different systems can take place on the basis of demand.

The switching system can optionally be disposed in a suitable housing in which the components are received and from which the different infeeds and outfeeds protrude.

The switch or valve is preferably configured to incorporate in the system, i.e. actively connect in the flow cycle, those systems which are relevant in accordance with the circumstances. Keeping solar collectors in the flow cycle at night is for instance not required, while the heat buffer need not be coupled to the system when the capacity of stored heat is too low or there is sufficient supply from the heat supply systems.

If desired, the heat supply system as well as the heat buffer and the heat take-off system can be connected so that a combined heat capacity of the heat supply system and the buffer can suffice for the heat take-off system. The heat supply system can for instance be coupled to either the heat take-off system, for instance when take-off of heat is desired, or to the heat buffer when no heat take-off is desired and the heat available through the heat supply system can be stored in the heat buffer. Such a switching option, wherein the heat supply system is connected and either the heat buffer or the heat take-off system is connected, and the other of the heat take-off system or the heat buffer is therefore disconnected, therefore provides the option of efficient sw itching between a momentary heat take-off requirement or a buffering option.

The heat take-off system and/or the heat supply system and/or the heat buffer can be coupled substantially directly to each other, preferably with the recirculation pump therebetween. The heat transfer agent flows here through the connected systems or buffer as one closed circuit. Such a direct system can be efficient.

The hot transfer agent provided by the heat supply system and/or heat buffer can for instance be used directly here by the heat take-off system.

An indirect coupling, for instance via a heat exchanger, can alternatively also be an advantageous solution because the recirculation pump in particular can then take a simpler fomi. this providing a cheaper system. In this case there is a closed heat transfer agent system for the heat buffer and/or a closed heat transfer agent system for the heat supply system and/or a closed system for the heat take-off system. Heat transfer between the diverse closed systems can take place via one or more heat exchangers. The heat transfer agents can here be the same or different agents.

A further preferred embodiment also comprises an outfeed and infeed for a hot w ater system, in particular a boiler, and a hot water system valve for connecting and disconnecting the hot water system. Depending on the heat available, for instance from the heat supply system and/or the heat buffer, the water in a hot water system can be heated. The valve is preferably located downstream of the infeed of the heat buffer and/or the infeed from the heat supply system, so that the heat obtained from these systems can be fed to the hot water system.

It is noted that the switching system according to the invention can also be used for buffer systems other than the buffer system according to the invention.

The invention further relates to a building provided with a (cold and) heat storage system with a switching system, in particular a switching system according to the invention, and operatively coupled thereto:

- a heat supply system, for instance a solar collector system and/or a heat exchanger system; a heat buffer, in particular a heat buffer according to at least one of the claims:

a heat take-off system, for instance a heating system.

Such a building is highly energy-efficient.

It is noted that the building can also comprise a switching system other than that according to the invention. According to a further preferred embodiment, the building comprises a surge system for creating a surge of heat transfer agent in the second container. It is hereby possible to break loose ice which may have formed on the common flexible wall. The surge system can for instance comprise a buffer with valve, wherein after coupling of the buffer to the system via the valve a larger quantity of transfer agent is carried briefly to the heat buffer It can also be possible for the surge system to temporarily reverse the flow direction in the infeed and outfeed of the heat buffer using a valve configured for the purpose in order to thus achieve a surge effect in this buffer. hi order to supply heat to the heat buffer it is advantageous for the building to comprise a solar collector system w hich is operatively connected to the storage system for the purpose of supplying heat to the heat transfer agent. The heat transfer agent can be heated efficiently using a solar collector, after which the heat in the heat buffer can be transferred to the relatively cold liquid in the first container.

According to a further preferred embodiment, the storage system comprises a heat exchanger disposed under the heat buffer and switchably coupled to the heat take-off system.

Such a heat exchanger can extract heat from the second container and supply it to the heat take-off system. The heat take-off system is in that case coupled to the heat buffer via the switching system. When the heat buffer is heated by the heat supply system, the heat take-off system can be disconnected from the heat buffer via the switching system. An advantage of such a system is that the recirculation pumps can take a simpler form.

The second container is preferably disposed between the first container and the heat exchanger such that it can be in heat-exchanging contact with the first container and the heat exchanger,

The heat exchanger can comprise a number of panels disposed at a distance from each other. It is in that case advantageous for the switching system to be configured to allow the heat transfer agent to circulate through the second heat exchanger, so that heat can also be transferred in efficient manner from those parts of the second container extending between the panels of the heat exchanger.

The heat exchanger can if desired form part of the heat buffer or of an assembly comprising the heat exchanger and the heat buffer. It can in that case form part of the heat buffer according to any of the claims 1-13 or form part of an assembly of the heat buffer according to any of the claims I - 13 and a heat exchanger disposed thereunder.

In this embodiment of the building the second container of the heat buffer preferably comprises a closed system for the heat transfer agent which can be indirectly connected to the heat supply system via a heat exchanger and indirectly connected to the heat take-off system via said heat exchanger.

The present invention is further illustrated on the basis of the following figures which show a preferred embodiment of the device according to the invention and are not intended to limit the scope of the invention in any way, wherein:

-Figure 1 shows a perspective view of the heat buffer;

-Figure 2 shows a cross-sectional view of the heat buffer in a cellar;

-Figures 3A and 3B show two views of the connections of the heat buffer;

-Figure 4 shows a cross-section of the heat buffer in detail at the position of the connections;

-Figure 5 shows a detail at the position of a discharge of the heat buffer;

-Figure 6 shows a schematic view of the heat buffer in a building;

-Figure 7 shows a schematic view of a variant of the heat buffer;

-Figure 8 shows a schematic view of another variant of the heat buffer;

-Figures 9-12 show schematic views of a variant of a heat storage system for a heat buffer in different situations; -Figure 13 shows a schematic view of another variant of the heat buffer;

-Figure 14 shows a schematic view of another variant of a heat storage system for a heat buffer, and

-Figure 1 shows a schematic view of another variant of a heat storage system for a heat buffer.

Figures 1 and 2 show a heat buffer 1 according to the invention. The buffer consists substantially of an outer bag 2 with upper wall 2a and lower wall 2b in which is arranged an inner bag 3 with upper wall 3a and lower wall 3b. Bag 2 has a height h of about 60 centimetres, a length 1 of about 6.5 metres and a width b of about 4 metres. The water volume of the outer bag is about 13.5 nr (13,500 litres). The volume of the inner bag is about 450 litres with an area of 14 nr. These dimensions allow heat buffer 1 to fit into a crawl space 100. Buffer 1 lies here on a piece of plasterboard 101 in which are arranged slots 101a in which the conduits, which will be discussed in more detail hereinbelow. can be received. Bag 3 is situated here on the underside of buffer 1, wherein walls 3b and 2b coincide. Bags 2 and 3 are manufactured from a rubber-coated textile and are of flexible and elastic nature.

Bag 2 forms a container for water 92 which can be filled via an infeed 7 and a conduit 75 via a tap 76, see figure 6. A heat transfer agent, in this example a glycol solution 91 , is carried through bag 3. Bag 3 is provided for this purpose with an infeed 5 which is oriented away from the centre in a direction A, see figures 3 A, 3B and 6. The glycol solution is pumped into bag 3 in a direction A through a feed conduit 55 which is connected to infeed 5. An outfeed 6 is conversely configured to receive the glycol solution from bag 3 from a direction B and discharge it via a discharge conduit 65. Outfeed 6 is provided for this purpose with a transverse tube 61 in which are arranged a plurality of inflow openings 62 which face in a direction away from the centre of bag 3.

The infeeds and outfeeds are arranged in a central distributing disc 4. This disc 4, see also figure 4, is provided with a lower disc 41 connected to and closing lower walls 2b and 3b watertightly. Arranged through this disc are infeed 5 and outfeed 6 as well as infeed 7 for bag 2. Then arranged using uprights 43 is a second disc 42 on which upper wall 3a of im er bag 3 is arranged watertightly, in this example by means of glueing. Just as bag 3, the space between discs 41 and 42 forms part of the container for the glycol solution. Infeed 7 for the water of bag 2 also protrudes through this second disc 42 so that it debouches into bag 2. so that this can be filled. Finally arranged on upper wall 2a of water bag 2 is an outfeed 8 which is shown in more detail in figure 5. Outfeed 8 comprises a housing 82 provided with a flange 81 which is glued onto upper wall 2a of water bag 2. Discharge conduit 85 is connected via a transverse pipe 83 to housing 82. Outfeed 8 can be used for venting, for instance during filling of bag 2.

Bag 3 which is situated in the outer bag 2 which contains water as buffer for cold or heat, has the function of heat exchanger. Relatively hot or cold glycol 91 (relative to the water 92 in bag 2) is introduced into bag 2 in direction A, see figure 6, and flows through bag 3 and via wall 3a to outfeed 6. Heat or cold is then exchanged with the water 92 via flexible wall 3a of bag 3 so that it can be recovered later if necessary. It is not unusual for ice formation to occur in bag 2 in a buffer of a cold and heat storage system. This occurs particularly on the surface of the heat exchanger, in this case wall 3a. Ice formation on a transfer surface of a heat exchanger is detrimental to an efficient transfer and must therefore be prevented. When a surge of glycol solution is now supplied to infeed 5, this will however result in an abrupt movement of, among other parts, wall 3a so that the ice which has formed there is shaken off and will float to the top of bag 2. designated with 93 in figure 6. Flexible wall 3a enables efficient de-icing of the heat exchanger.

Supplying this surge is performed in this example by a surge system 127 which forms part of a cold and heat storage system arranged in a building and shown schematically in figure 6. System 127 is provided with a valve 127b w ith timer which is connected to a pressure vessel 127a. so that at set times a surge of glycol can be supplied via feed 55 to bag 3 in order to prevent ice formation on the surface of wall 3 a.

Supplying heat to buffer I can for instance take place using solar panels 1 10. Infeed 55 of heat buffer 1 is coupled for this purpose via conduit 122a, valves 12 1. 122 and recirculation pump 123 to outfeed conduit 1 12 of the solar panel system 1 10. Glycol solution heated by the sun is pumped here into bag 3 so that the heat is transferred to the water 92 in bag 2. Outfeed 65 of heat buffer 1 is then in turn coupled via valves 12 1 and conduit 12 1 a to feed conduit 1 1 1 of the solar panel system 110.

Heat stored in bag 2 can be supplied via the heat exchanger embodied as bag 3 to a floor heating system 126 via valves 121 and 122 and via pump 124. Outfeed 65 is coupled here via suitable valves to infeed 126a of the floor heating system. Outfeed 126b of this system 126 can in turn also be coupled to infeed 55 of heat buffer 1. It is also possible to supply the relatively hot glycol solution via valves 122 and pump 124 to a heat exchanger of the hot water system 125 of a building. Figure 7 shows a variant of the heat buffer, wherein figure 7A shows a cross-section along the line A-A in figure 7B. In the heat buffer the second container 3a is formed by a membrane 38a which is arranged on a lower wall 38a of first container 2. Container 3a is therefore formed by a double wall of outer bag 2. Container 3a is formed particularly here by a bag which is formed by lower wall 38a of first container 2 and the membrane 38a arranged thereon. In this embodiment the first container 2 formed as bag and second container 3a formed as bag have one common wall, lower wall 38a. At peripheral edge 39a membrane 38a is connected to wall 38b of bag 2 by for instance (fusion) welding or glueing. Tnfeed 5 and infeed 6 are arranged close to edge 39a, particularly on a first side of bag 2. Membrane 38a and wall 38b are further mutually connected along connecting zones 39 extending in the direction from the first side to an opposite second side of bag 2 for the purpose of forming a meandering flow profile in second bag 3a, as indicated with arrow s in figure 7B. In this embodiment two parallel, meandering channels are created between infeed 5 and outfeed 6 which can be connected to conduits of the systems as shown in figures 6 or 9. Connecting zones 39 form guide means here for guiding the flow of the heat transfer agent over substantially the whole surface of membrane 38a which forms the common wall of the two containers 2, 3a embodied as bags.

Figure 8 shows another variant of heat buffer 1 of figures 1-6, wherein infeed and outfeed 5 and 6 are arranged non-centrally in heat buffer 1. Infeeds and outfeeds 5 and 6 are more specifically situated more in the direction of the edge of the heat buffer, so that simpler connection to the system is possible.

Figures 9-12 show a simplified heat storage system, in each case with a different use. The flow of the heat transfer agent in the conduits is indicated with the full lines. In figures 9-12 an infeed is understood to mean a connection for a conduit with a flow of heat transfer agent in a direction into the switching device. An outfeed is then configured to be connected to a condviit with a flow in the direction away from the switching device.

Figure 9 shows the system wherein heat from thermodynamic panels 1 10a arranged on the roof, for instance solar collectors and/or heat exchangers, is supplied to a boiler 125 and wherein heat is supplied simultaneously from buffer 1 to heat pump 124a and subsequently to outfeed 126a of a floor heating system 126. Switching between the associated conduits of these systems takes place with a switching device 1000 which is provided with a recirculation pump 123. Switching device 1000 is provided with an infeed 1001a for connection to conduit 65 of heat buffer 1 for the purpose of supplying the heat transfer agent to switching device 1000. Outfeed 1001b is coupled to conduit 55, the feed for heat buffer 1. Outfeed 1002b serves for outfeed of transfer agent to panels 110a. Infeed 1002a serves for the infeed from panels 110a. Use is made in panels 110a of another heat transfer agent, in this example 134a or R407c. wherein the system is provided with a compressor 1101 and throttle valve. The heat exchange with the glycol takes place in heat exchanger 1100 which is placed downstream of recirculation pump 123. hi a variant of this embodiment it is possible to arrange a valve upstream of heat exchanger 1 100 in order to sw itch the heat exchanger out of the flow. This can be particularly useful when use is made for panels 1 10a of solar collectors which have a yield which is sometimes insufficient. These solar collectors can then be switched off in simple manner.

The heated glycol is guided from heat exchanger 1100 toward outfeed 1009b to boiler 125 via valve 1005 which is situated between outfeed 1001b to heat buffer 1 and heat exchanger 1 100. Via an infeed 1009a the glycol is again supplied via pump 123 to heat exchanger 1100. Valve 1005, in combination with valve 1006 which will be discussed in more detail below, can switch the outfeed of the relatively hot glycol of the heat supply system embodied as heat exchangers between a heat take-off system, in this case boiler 125. and buffer 1. Shown for instance in figure 10 is that valves 1005 and 1006 have been switched such that the glycol from pump 123 is directly coupled via heat exchanger 1100 to the outfeed 1001b to buffer 1, so that the heat from heat supply system 1 10a can be stored in buffer 1. Infeed 1001a of the buffer is then in turn coupled to the inlet of pump 123.

Referring once again to figure 9, valve 1006 also has the function of coupling infeed 1001a of buffer 1 to an outfeed 1008b to water pump 124a. Infeed 1008a of heat pump 124a is then simultaneous!} ⁷ coupled to outfeed 1001b of heat buffer 1. In this situation valve 1006 closes the conduits of infeed and outfeed 1001a,b of the buffer to pump 123 so that a second circuit is created in switching device 1000. Outfeed 1008b in heat pump 124a is more specifically connected to outfeed 126a for the floor heating system 126. Infeed 126b from the floor heating system 126 is connected via valve 1007 over pumps 1007a and 1007b so as to be coupled via selector valve 1201 to outfeed 1200b. which is in turn connected to infeed 1008a of switching device 1000. Pumps 1007a and 1007b provide here for a secondary system, so that the floor can be heated w ith heat from buffer 1 simultaneously with heating of boiler 125 with heat exchangers 100a (via pump 123). With valves 1007 and 1201 it is possible to switch the glycol between the floor heating system 126 and boiler 125. By closing infeed 126b of the heating system the glycol is not carried via outfced 126a to heating system 126 but through conduit 126c to boiler 125. Conduit 126b is also connected to outfeed 1009b. Glycol will not however flow into the switching device owing to non-return valve 1009c.

The glycol flows from boiler 125 back into heat pump 124a via conduit 126b, which is also coupled to infeed 1009a but where no flow takes place due to disconnection of pump 123, and is fed back via valve 1007 and pumps 1007a and 1007b to heat buffer 1.

Figure 12 shows the heating of the floor heating system 126 from panel 1 10a. Valve 1005 is once again switched in this situation to outfeed 1009b, wherein the hot glycol is supplied via intermediate conduit 126c to outfeed 126a of heating system 126. Valves 1201 and 1007 are now switched such that infeed 127b is directly connected to outfeed 126d. Pumps 1007a and 1007b of heat pump 124a are switched off here. Outfeed 126d is again coupled to infeed 1009a. Valve 1006 in switching device 1000 here blocks the infeeds and outfeeds 1008a,b and 1001a,b.

Figure 13 shows a variant of the heat buffer, wherein figure 13A shows a cross-section along line A-A in Figure 13B. As in the embodiment of figure 7, second container 3a is formed by a membrane 38a arranged on a lower wall 38a of first container 2. Container 3a is therefore formed by a double wall of outer bag 2. Container 3a is particularly formed here by a bag which is formed by lower wall 38a of first container 2 and membrane 38a arranged thereon. In this embodiment the first container 2 formed as bag and second container 3a formed as bag have one common wall, lower wall 38a. Membrane 38a is connected by fusion to wall 38b of bag 2 at peripheral edge 39a. hi the embodiment of figure 13 four pairs of infeeds and outfeeds 5. 6, which are arranged close to edge 39a, are provided, in particular on a first side of bag 2. Membrane 38a and wall 38b are mutually connected, for instance by fusion, along connecting zones 39b,c extending from the first side in the direction of an opposite second side of bag 2 for the purpose of forming channels in second bag 3a. In this example two parallel channels, which can be connected to conduits of the systems as show n in figures 6, 9 or 14. are created in each case between each pair of an infeed 5 and an outfeed 6. Close to the second side opposite infeed and outfeed 5, 6 the one connecting zone 39b in each case extends to a determined distance, greater than zero, from peripheral edge 39a, so that an opening is created for reversing the heat transfer agent round connecting zone 39b. The other connecting zone 39c extends as far as peripheral edge 3 a so that it creates a closed pair of two parallel channels between each pair of infeeds 5 and outfeeds 6. The one and other connecting zones 39b,c are disposed alternately here.

Connecting zones 39b.c form guide means here for guiding the flow of the heat transfer agent over substantially the whole length of the membrane 38a forming the common wall of the two containers 2, 3a embodied as bags. Because a total of four pairs of parallel channels are formed, the heat transfer agent will flow over substantially the whole surface of the membrane 38a forming the common wall of the two containers 2, 3a embodied as bags.

Figure 14 shows a simplified heat storage system. The flow of the heat transfer agent in the conduits is indicated with the full lines. Figure 14 shows the situation where delivery to the heat take-off system takes place from the heat buffer, and where the heat buffer is heated from thermodynamic panels 1 10a on the roof or other location. The other situations are not shown, but will be apparent to the skilled person. Only the (significant) differences from the system of figures 9-12 will be described. Reference is made to the description relating to figures 9-12 for a further description of the system of figure 14.

The switching system according to figure 14 is a simplified system compared to that of figures 9- 12. A difference is that conduits 1009a, 1009b have been omitted. Another difference is that the pump module box with recirculation pump 123 takes a simpler form.

Figure 1 shows another simplified heat storage system. The flow of the heat transfer agent in the conduits is indicated with the full lines. Figure 15 shows the situation where delivery to the heat take-off system takes place from the heat buffer and panels 110a on the roof or other location. The other situations are not shown, but will be apparent to the skilled person. Only the (significant) differences from the system of figures 9-12 will be described. Reference is made to the description relating to figures 9-12 for a further description of the system of figure 15.

In the system of figure 15 a number of heat exchanger panels 1110a are arranged under heat buffer 1. For the sake of clarity heat buffer 1 is shown both in vertical longitudinal section at its location under the floor and in a schematic transparent top view so that panels 11 10a are clearly visible. The construction in this system, as seen from top to bottom in vertical direction, is first container 2, second container 3(a) and then heat exchanger panels 1 1 10a. Second container 3a is therefore sandwiched bet een first container 2 and heat exchanger panels 1110a. When the buffer has to be filled, heat from panels 110a can be relinquished via second container 3(a) to the water in bag 2. When heat has to be extracted from the buffer, for instance for floor heating 126, heat can be extracted from bag 2 via second container 3(a) and heat exchanger panels 11 10a. An advantage of this system is that, although two circulation pumps 123a, 123b are provided, the circulation pump is of simpler and cheaper type.

Elongate upright elements can if desired be arranged under buffer 1 which press the lower wall of the second container upward in the area of the elements in the direction of the upper wall of the second container. The volume of the second container is hereby reduced, although the heat- transferring area with the first container remains substantially the same. A smaller volume of heat transfer agent is hereby possible.

The present invention is not limited to the shown embodiments but extends to other embodiments falling within the scope of the appended claims.

It will for instance be apparent that the switching system can be embodied in any desired and suitable manner. A number of examples which show that diverse diagrams are possible are thus shown for the purpose of illustration.