EP3667182B1 - Heat pump assembly - Google Patents

Description

The invention relates to a heat pump system that is designed for simultaneous heating and cooling.

There are many different applications with simultaneous heating and cooling requirements. An example is the supply of a building from which heat has to be dissipated (e.g. server room) and at the same time heat has to be supplied at another point (e.g. heating of offices). Such supply tasks can be carried out in different ways. One possibility is to ensure the heat is supplied by an electrically or fossil-fuelled heat generator and the heat is removed by a chiller.

In addition, there is also the possibility of ensuring such a holistic supply of a building using a heat pump cycle using a heating-cooling system. For this purpose, a heat pump is integrated in such a way that both its heat source side and its heat sink side are used for heating and cooling at the same time. For this purpose, the heat pump has an evaporator on the heat source side and a condenser on the heat sink side. The evaporator is to be cooled by a heat transfer medium such. B. cooling water flows through. The condenser is simultaneously heated by a heat transfer medium, e.g. B. heating water flows through. Since in this case heat is shifted from the heat source side to the heat sink side, this type of integration and supply is also referred to as heat shift in the following.

With such parallel heating and cooling systems, however, it should be noted that the heating and cooling capacity requirements in most applications, especially in building supply, are not in the same, constant ratio to one another and, in particular, fluctuate over the year. For example, the cooling capacity requirement will typically predominate in the warm summer months and the heating capacity requirement in the colder winter months.

In order to nevertheless ensure the supply of a building, for example, on the basis of the heat displacement described above, additional heat is supplied or removed, depending on the current situation. If there is an increased need for cooling, for example, excess heat is dissipated to the environment. Conversely, when there is an increased heating requirement, additional heat is absorbed from the environment. The environment is in each case outside the area to be supplied, for example outside the building to be supplied with heat/cold. However, this is often associated with losses in efficiency.

From the EP 1 674 802 A2 is a multifunctional center for heating and/or cooling for residential buildings. The center has a cold storage tank, which is fed with ambient heat from a solar system or an air-water heat pump. In winter operation, a water-water heat pump takes heat from the cold storage tank and feeds it into a hot water storage tank, which is used to supply rooms. In summer operation, the air-water heat pump is used directly to cool the rooms.

Proceeding from this, the present invention is based on the object of specifying a heat pump system which is designed for simultaneous heating and cooling and which has a high level of efficiency, in particular the highest possible TER index (Total Efficiency Ratio).

The object is achieved according to the invention by a heat pump system with the features of claim 1. The heat pump system is for simultaneous Formed heating and cooling and has a first heat pump, which is designed as a liquid-liquid heat pump. The heat pump is connected to a heat source on a source side and to a heat sink on a sink side, each via a liquid/liquid heat exchanger. The heat pump generally has a refrigerant circuit with an evaporator and a condenser and with an electrically driven compressor.

If a liquid-liquid heat pump is used here, this means that a liquid is used as the heat carrier on both the source side and the sink side, so that the heat on the source side is transferred from the liquid to a refrigeration circuit of the heat pump or heat is transferred from the sink side Refrigeration cycle is discharged into the liquid. The liquid can be water, brine or a water-glycol mixture. Different heat carriers can be used on the source side and sink side, for example water on the one hand and brine on the other. Brine and water-glycol mixtures often have a freezing point below 0°C and are therefore suitable for cooling circuits with particularly low temperatures. In the following, the term "brine" is used both for the actual brine (solution of technical salts in water) and for a glycol-water mixture.

The heat source generally has a cooling circuit in which a liquid (water or brine) circulates as a heat carrier during operation and which has a cooling flow, a cooling return, a cooling buffer tank for cold water and - when connected - at least one Has cooling consumer.

This serves to cool its surroundings and absorbs heat from the surroundings and transfers it to the liquid of the cooling circuit. Environment is understood here to mean that, for example, the ambient air of the

Cooling consumer is cooled or another heat transfer medium. The cooling consumer, also referred to as a cooler, is preferably used for room cooling. Depending on the application, the cooler can also be used for other cooling purposes, e.g. B. be used for cooling cold or freezer rooms.

The heat pump system is used in particular for building air conditioning and, if necessary, additionally for the provision of heated service water. Alternatively, the heat pump system is used, for example, in the food and beverages industry and/or in industrial processes where there is a need for cooling, e.g. B. for cooling food, equipment, etc. and a heating requirement z. B. for building heating, water heating, for heating equipment, etc. is required.

In a similar way, the heat sink includes a heating circuit in which a liquid (in particular water) circulates as a heat carrier during operation with a heating flow, a heating return, a heating buffer storage tank for heating water and - when connected - with at least one heating -Consumers who are trained to heat their surroundings. The heating consumer is preferably used in turn for direct heating, for example, the air in a room, but can also be used to heat another heat transfer medium. The heat source and/or the heat sink is preferably finally formed by the cooling circuit or heating circuit connected to it.

As an alternative and in particular as a supplement to the heating buffer tank and the heating consumer, the heating circuit has a hot water tank in which service water is heated.

During operation, more precisely in a specific operating mode (normal operation), heat is shifted between the cooling circuit and the heating circuit via the first heat pump, so that cooling capacity is provided on the cooling circuit side and heating capacity on the heating circuit side at the same time. In particular, heat/cold is shifted between the two circuits and in particular between the cooling buffer tank and the heating buffer tank or hot water tank. In particular, heat is shifted from the cooling buffer tank to the heating circuit, specifically to the heating buffer tank/to the hot water tank. Alternatively or in addition, the cold comes from the The heating buffer tank / the hot water tank is shifted to the cooling circuit, specifically to the cooling buffer tank.

Normal operation is understood here to mean an operating situation in which the first heat pump is in operation. The first heat pump is only operated under predetermined boundary conditions, in particular temperature conditions in the heating circuit or in the cooling circuit.

In order to provide heat compensation for different heat or cooling requirements, an additional unit is also integrated into the heat pump system, which is hydraulically connected to both the cooling circuit and the heating circuit and, if necessary, is fluidically connected to either the cooling circuit or the heating circuit via appropriate valves, for example so that either additional heat is fed into the heating circuit or additional cold is hydraulically fed into the cooling circuit. As an alternative to a fluidic connection, heat or cold is transferred to the heating circuit or cooling circuit by means of a heat exchanger. This applies in particular if different liquids are used in the cooling circuit (or in the heating circuit) and the connected additional unit (e.g. brine/water) and the liquids must be separated.

Connected hydraulically and/or fluidically means that a liquid exchange takes place from a circuit connected to the additional unit to the cooling circuit or to the heating circuit.

Hydraulically connected is generally understood to mean a pipe connection for the liquid, which can be closed via a valve if necessary. The at least one additional unit is designed both to provide additional heat for the heating circuit and to provide additional cold for the cooling circuit and provides either heat or cold as required.

Furthermore, the heat pump system as a whole has a control unit that is designed to control the operation of the heat pump system.

The heat equalization is therefore provided hydraulically via the additional unit. It is therefore not necessary for the first heat pump—for example when there is an increased need for cooling—to emit heat unused to the environment. The first heat pump can therefore be operated in a highly efficient manner overall. Efficient operation is also supported by the integrated buffer storage. As a result, on the one hand, a desired temperature level can be maintained even with fluctuating load requirements and - at least temporary - shifts between the required cooling capacity and heating capacity can be adjusted via the respective buffer storage z. B. be intercepted by overheating or overcooling without the need to switch on the at least one additional unit. Overheating or undercooling is generally understood to mean an additional heat input or cold input into the buffer storage tank above a target temperature and up to a maximum/minimum temperature.

This additional unit is a second heat pump, which is designed as a reversible air/liquid heat pump. This has a refrigerant circuit with an air-refrigerant heat exchanger and a refrigerant/liquid heat exchanger. The second heat pump can still be operated in reverse, so that the heat exchangers can be used as an evaporator and as a condenser, depending on the operating mode. The air/refrigerant heat exchanger absorbs heat from the ambient air in a heating mode and gives off heat to the ambient air in a cooling mode. Correspondingly, via the refrigerant/liquid heat exchanger, heat is released in the heating mode and cold is provided in the cooling mode. Both the heat displacement and the heat equalization are therefore provided by two heat pumps, namely the first heat pump and the second heat pump. While the first heat pump cannot be operated in a reversible manner, a particular advantage of the second heat pump can be seen in its reversible operating mode, so that both heat and cold can be provided with just one additional unit.

For the hydraulic integration of the second heat pump, it can be fluidically connected either to the heating circuit or to the cooling circuit via a first multi-way valve, which is designed in particular as a switching valve. Fluidically connectable is understood to mean that the liquid flowing through the refrigerant/liquid heat exchanger of the second heat pump is fed directly fluidically into the heating circuit or into the cooling circuit, ie a liquid exchange takes place. In this case, the second heat pump is fluidically connected only to the heating circuit in the heating mode and only to the cooling circuit in the cooling mode.

In a preferred embodiment, a feed bypass line is provided for this purpose, which connects the cooling feed to the heating feed. Furthermore, the second heat pump has a flow, which is typically connected to the refrigerant-liquid heat exchanger. This flow is fluidically connected via the first multi-way valve in the cooling mode with the cooling flow of the cooling circuit and in the heating mode with the heating flow of the heating circuit.

Furthermore, in a preferred embodiment, a return bypass line is formed, which connects the cooling return to the heating return. Furthermore, the second heat pump also has a return, which in turn is connected to the refrigerant-liquid heat exchanger. This is in turn fluidly connected via a second multi-way valve in the cooling mode to the cooling return and in the heating mode to the heating return.

The two bypass lines and the two multi-way valves, which are designed in particular as simple changeover valves, achieve an expedient hydraulic integration of the second heat pump into the heating circuit or the cooling circuit of the heat pump system.

In a preferred embodiment, the respective consumer is either connected in series to the respective buffer store assigned to it or arranged in parallel thereto. The consumer is in each case in a consumer group integrated. The flow for the consumer is connected to the buffer tank. With the parallel connection, the return flow of the consumer is also connected to the buffer tank. In contrast to this, when the consumer is arranged in series, the consumer return is directly connected to the heating return or the cooling return. If it is said here that a respective consumer is connected to the respective buffer memory assigned to him, this means that the heating consumer is connected to the heating buffer memory and the cooling consumer is connected to the cooling buffer memory. Connected is also understood to mean a hydraulic connection in each case.

With a view to operating the entire heat pump system as efficiently as possible, appropriate control and regulation of the entire heat pump system using the control unit is provided.

According to a preferred embodiment, the first heat pump has priority over the additional unit, ie over the second heat pump. This is initially understood to mean that, in principle, the heat is only shifted via the first heat pump and the additional unit is only switched on when additional heating or cooling is required. The first heat pump is therefore always in operation (normal operation) as long as it is permissible - within specified temperature limits - to move heat from the cooling circuit to the heating circuit. The first heat pump is only blocked for operation when a maximum heating temperature in the heating buffer tank or a minimum cooling temperature in the cooling buffer tank is reached. This operating mode, in which normal operation is prevented and in particular only the additional unit is active, is called Additional operating mode called. In this case, heat displacement between the heating circuit and the cooling circuit is no longer permissible, since this would lead to the desired maximum heating temperature being exceeded or the desired minimum cooling temperature not being reached.

The control unit is also designed in such a way that the additional unit, ie the second heat pump, is only switched on when the temperature in the heating buffer storage falls below a target heating temperature or the target cooling temperature in the cooling buffer storage is exceeded. Depending on which target temperature is exceeded or fallen below, additional heat is introduced into the heating circuit or additional cold into the cooling circuit by means of the additional unit. As long as the maximum heating temperature is not exceeded or the minimum cooling temperature is not fallen below, the additional unit is in operation in addition to the first heat pump. I.e. the normal operation is supplemented by the heating mode or the cooling mode of the additional unit. This operating mode is referred to as the support operating mode and is therefore a combined operating mode that is made up of normal operation and the heating or cooling mode.

Provision is also made for the additional unit to be switched off when the heating target temperature in the heating buffer storage is exceeded or the cooling target temperature in the cooling buffer storage is undershot. The additional unit is therefore used to regulate the temperature to the target temperature. In contrast to the first heat pump, no overheating or undercooling of the respective buffer storage is provided.

The temperature values (target temperatures or min-max temperatures) each define switching points for the control and regulation of the heat pump system. Switching, for example switching the additional unit on or off, switching the first heat pump on or off, takes place when the target temperature or the minimum and maximum temperatures (also referred to as switching temperatures) are exceeded or not reached, with each of these temperature values also having a Hysteresis is provided, i.e. switching only takes place if the respective temperature (switching temperature) plus a hysteresis temperature value of e.g. B. 2 to 5K, especially 3K, exceeded or fallen below.

The desired heating temperature is expediently in a range from 30° to 60°C and in particular in a range from 30° to 45°C.

In addition or as an alternative, the desired cooling temperature is preferably in a range from 5° to 20°C and in particular in a range from 8° to 18°C, for example preferably 15°C. In this case, water in particular is used as the heat carrier in the cooling circuit. Such temperatures in the cooling circuit are used in particular for cooling rooms used by people.

If - depending on the application - colder temperatures are required, for example for cold rooms or refrigerated counters, the target cooling temperature is in a range from -15°C to 20°C, in particular in the range from -9°C to 10°C.

The heating target temperature is preferably about 35°C. In general, the cooling target temperature - in an application for building air conditioning - for example by 10 ° to 20 ° C or 10 ° to 25 ° C below the heating target temperature. In these temperature ranges, a good building supply is achieved both for room air conditioning and for the provision of service water, for example.

The setpoint temperatures relate in particular to the hottest (heating buffer storage) or coldest (cooling buffer storage) temperature in the buffer storage, in particular at an output of the buffer storage in a flow path to the consumer. The return temperatures from consumers are correspondingly lower (in the heating circuit) or higher (in the cooling circuit), for example by 5-10K.

A temperature difference between the maximum heating temperature and the desired heating temperature is expediently in the range between 5 and 25K and in particular in the range between 10 and 15K. Furthermore or alternatively, a temperature difference between the minimum cooling temperature and the target cooling temperature is in the range between 5 and 20K and in particular in the range between 8 and 12K.

According to a preferred further development, the difference between the heating target temperature and the cooling target temperature is still - in particular in an application for building air conditioning - in the range from 10 to 40K, and especially in the range from 15 to 35K.

As a result, there is the possibility that the respective buffer storage tank can be sufficiently charged with heat or cold, so that the use of the additional unit is reduced to a necessary minimum.

The specified temperature values, i.e. both the setpoint temperatures and the maximum/minimum temperatures, can preferably be set in each case, either during production when the heat pump system is configured, but preferably also during operation, for example by the user, or also automatically, in particular depending on current requirements. e.g. B. a current ambient temperature.

With regard to the most energy-efficient operation possible, the control unit is also designed in such a way that the additional unit is only switched on in an additional operating mode when the first heat pump is blocked for operation. Therefore, no simultaneous operation of the first heat pump and the additional unit, ie the second heat pump, is provided in the additional operating mode.

The first heat pump is preferably only designed for part of the maximum heating and/or cooling requirement, for example only up to a maximum of 75% or only up to a maximum of 50% of the maximum heating and/or cooling requirement. This is generally understood to mean that - based on a maximum required heating output and maximum required cooling output determined for the respective object (e.g. building, process) - the first heat pump is only used for part of this specific heating output and/or or cooling capacity is designed. This ensures that operation is as permanent as possible in the sense of a base load by the first heat pump.

The additional unit is switched on for additional heating or cooling requirements.

Depending on the current requirement, it is then in the support operating mode the required heat or cold is ensured both by heat displacement via the first heat pump and by additional heat or cold input via the second heat pump.

In a preferred embodiment, the heating and cooling capacity of the first heat pump is also lower than the heating and cooling capacity of the additional unit, ie the second heat pump. It is preferably only a maximum of 80% or only a maximum of 50% of the heating and cooling capacity of the additional unit, ie the second heat pump.

In a preferred development, the control unit is also designed in such a way that the minimum cooling temperature and/or the maximum heating temperature is varied during operation of the heat pump system. As an alternative to the variation of these minimum or maximum temperatures, in a preferred embodiment, the temperature difference to the respective setpoint temperature, ie to the heating setpoint temperature or cooling setpoint temperature, is varied automatically.

This measure makes it possible during operation to adapt the loading status of the buffer storage tank, i.e. the degree of overheating or undercooling, to current situations, for example setting a higher loading status of the heating buffer storage tank when a large amount of heat is currently available. This is the case, for example, when the provision of heat is additionally supported by a solar-generated energy input, for example by a solar thermal system, in which solar-heated heating water is used to load the heating buffer tank. In a preferred embodiment, a regenerative heating or cooling generator is therefore additionally connected to the heat pump system. A regenerative heat or cold generator is understood to mean a generator that generates the heat/cold using regeneratively generated energies (solar, wind power ...).

According to an expedient refinement, the control unit is also designed in such a way that the aforementioned variation takes place as a function of a currently excess energy supply or a current energy price.

The excess energy supply is, for example, the previously mentioned solar-generated heat. However, the control unit preferably also takes currently valid energy prices into account as an alternative or in addition. For example, during favorable electricity tariff times (night electricity), the maximum or minimum temperature is set higher or lower, so that the degree of loading of the buffer storage is increased, which is charged at more or less low energy prices. At the same time, excessive loading beyond what is necessary is avoided during peak periods of high energy prices.

For example, the control unit is also integrated into an intelligent power distribution network so that energy is temporarily stored in the buffer storage tanks when the network loads are low by increasing the maximum/minimum temperatures.

Fig. 1

ein vereinfachtes Schaltbild einer Wärmepumpenanlage, bei der der Verbraucher in Reihe geschalten ist,

Fig. 2

ein weiteres vereinfachtes Schaltbild einer Wärmepumpenanlage, bei dem der Verbraucher parallel geschalten ist,

Fig. 3A bis 3C

Flussdiagramme zur Erläuterung der Steuerung und Regelung der Wärmepumpenanlage.

An embodiment of the invention is explained in more detail below with reference to the figures. Some of these show in simplified representations:

1

a simplified circuit diagram of a heat pump system in which the consumer is connected in series,

2

another simplified circuit diagram of a heat pump system, in which the consumer is connected in parallel,

Figures 3A to 3C

Flow charts to explain the control and regulation of the heat pump system.

The in the Figures 1 and 2 The heat pump system 2 shown has a first heat pump 4 to which a cooling circuit 6 is connected on a source side as a heat source and a heating circuit 8 is connected on a sink side as a heat sink. The first heat pump 4 has, in a manner not shown in detail, a conventional structure with a refrigerant circuit in which an evaporator is connected in particular on the heat source side and a condenser is connected on the heat sink side. The evaporator and the condenser are each designed as a refrigerant/liquid heat exchanger in order to remove heat absorb a liquid heat transfer medium of the cooling circuit 6 and give off heat to a liquid heat transfer medium of the heating circuit 8 .

The cooling circuit has a cooling flow 6A and a cooling return 6B. Correspondingly, the heating circuit 8 also has a heating flow 8A and a heating return 8B. A cooling buffer store 10 and a cooling consumer 12 are integrated into the cooling circuit 6 in each case. Correspondingly, a heating buffer tank 14 and a heating consumer 16 are integrated in the heating circuit 8 . In principle, more than one consumer 12,16 can be integrated into the respective cooling or heating circuit 6,8. In the heating circuit 8, a hot water tank 18 for hot water is still involved.

A first temperature sensor R1 is also assigned to the cooling buffer storage tank 10 and a second temperature sensor R2 is assigned to the heating buffer storage tank 14 . These measure the temperature T_R1, T_R2 in the area of the respective buffer store 10, 14, preferably at the outlet of the buffer store, alternatively a temperature at the inlet or inside the buffer store. The following temperature values for the target temperatures or the maximum/minimum values refer to temperatures when the temperature sensor R1, R2 is arranged at the buffer outlet.

Furthermore, the heat pump system 2 has pumps 20 both in the heating circuit 8 and in the cooling circuit 6 . A pump 20 is connected in the exemplary embodiment in each case in the cooling return 6B or in the heating return 8B and in each case a further pump below the respective buffer memory 10,14 before the respective consumer 12,16 in a consumer circuit. In the 1,2 the respective supply 6A, 8A to the respective consumer 12,16 is represented by a solid line and the return 6B, 8B by a dashed line.

When designing the 1 a consumer flow is arranged at an outlet of the respective buffer memory 10,14 and a return of the consumer 12.16 is directly connected to the cooling return 6B or heating return 8B. In contrast to this series arrangement is in the variant according to the 2 a parallel arrangement of the respective consumer 12,16 is provided. For this purpose, the consumer -return is connected to the buffer memory 10.14.

Furthermore, a valve 24 is arranged in the cooling circuit 6 or heating circuit 8, which is designed in particular as a mixing valve. At least part of the heat transfer medium flowing back from the consumer 12, 16 can be added to the heat transfer medium flowing out of the buffer store 10, 14 in order to set a desired mixing temperature. To compensate for pressure differences in the flow and return is in the variant of the 1 Furthermore, a compensation element, in particular a so-called double differential pressureless distributor 25 is arranged.

It is also of particular importance that the heat pump system 2 has a second heat pump 26 which is designed as a reversible air/liquid heat pump. This has a refrigerant/liquid heat exchanger, not shown in detail here, which is connected on the one hand to an inlet 26A and to a return 26B.

Furthermore, a feed bypass line 28 is arranged, which connects the cooling feed 6A to the heating feed 8A, bypassing the first heat pump 4 . Furthermore, a return bypass line 30 is arranged in a comparable manner, which connects the cooling return 6B to the heating return 8B, bypassing the first heat pump 4 . The feed 26A of the second heat pump 26 is now connected to the feed bypass line 28 via a first multi-way valve 32, which is preferably designed purely as a switching valve. At the same time, the return 26B is connected to the return bypass line 30 via a second multi-way valve 34, which is also preferably in the form of a simple switching valve.

In the Figures 1 and 2 a frame is shown in each case, which is a system boundary between the actual heat pump system and the consumer circuits connected to it when installed. For this purpose, interfaces, for example connections, are provided at the system boundary, via which the consumer circuits are connected.

The heat pump system 2 shown serves to provide heat on the part of the heating circuit 8 and cold on the part of the cooling circuit 6 at the same time. The first heat pump 4 has priority over the second heat pump 26 and is designed to ensure that the two buffer storage tanks 10, 14 are kept at a specific temperature level and in particular do not fall below a heating setpoint temperature T_Soll,Hz or in the cooling buffer tank 10 a cooling setpoint temperature T_Soll ,K is not exceeded. Loading of the respective buffer store 10, 14 with cold or heat is provided up to a maximum heating temperature T_max in the heating buffer store 14 or up to a minimum cooling temperature T_min in the cooling buffer store 10. The target temperatures and the maximum/minimum temperatures are preferably adjustable and can also be varied during operation. The heat pump system 2 is operated in such a way that the setpoint temperatures T_Soll,Hz; T_Soll,K is controlled. For this purpose, the first heat pump 4 is operated with priority, for example continuously or in cycles. If there is an excessive heating requirement, heat is increasingly withdrawn from the cooling circuit 6, so that the cooling buffer store 10 is quasi “supercooled”. Conversely, the heating buffer tank 14 is "overheated" when there is an excess cooling requirement. If the preset maximum heating temperature T_max or the minimum cooling temperature T_min is reached, further operation of the first heat pump 4 is blocked. Any additional heating or cooling requirement is then provided by the second heat pump 26 . This is also designed as an electric compression heat pump, but in contrast to the first heat pump 4 can be operated in reverse, ie the circuit can be operated in the reverse direction of flow by appropriate control. The function of the heat exchanger of the second heat pump 26 can therefore be switched between the evaporator and the condenser by reversing the direction of flow.

Based on the Figures 3A to 3C The control is explained in more detail in the flow charts shown:
According to the Figure 3A After starting the heat pump system 2, the temperature values T_R1, T_R2 of the temperature sensors R1, R2 are first queried and evaluated. These temperature values T_R1, T_R2 are used to determine whether there is a heating or cooling requirement. If this is not the case, the first heat pump 4 and the second heat pump 26 are deactivated, ie switched off, or are not switched on. Ie the refrigerant circuit is not active, there is no heat displacement.

However, if it is determined that there is a need, then it is also checked whether the first heat pump 4 is enabled. If this is not the case, the second heat pump 26 is switched on. If the first heat pump 4 is enabled on the other hand, the first heat pump 4 is activated and switched on, so that heat is shifted from the cooling circuit 6 to the heating circuit 8 . If the second heat pump 26 is activated, heat is equalized.

The temperature values T_R1, T_R2 are queried and evaluated continuously during operation, for example at discrete time intervals. If the second heat pump 26 is switched on, it either only introduces heat into the heating circuit 8 or cold into the cooling circuit 6. If, for example, the first heat pump 4 is released again later due to the operation of the second heat pump 26, this is preferably the case the second heat pump 26 deactivated again. This means that the diagram according to the Figure 3A can be supplemented to the effect that subsequently to the check as to whether the first heat pump 4 is released, in the "yes case" it is still checked whether the second heat pump 26 is active. If this is the case, it is switched off.

The control and regulation of the heat pump system 2 takes place with the aid of a control unit not shown in detail here.

The diagram according to Figure 3B shows the control algorithm for querying whether there is a demand. For this purpose, it is checked whether the temperature T_R1 of the first temperature sensor R1 is greater than the cooling target temperature T_Soll,K. Furthermore, it is checked whether the temperature T_R2 of the second temperature sensor R2 is lower than the desired heating temperature T_Soll,Hz. If one of these conditions is met, a need is recognized.

Figure 3C shows the control algorithm for querying whether the first heat pump 4 can be released. Here it is checked whether the temperature T_R1 of the first temperature sensor R1 is greater than the minimum cooling temperature T_min. In addition, it is checked whether the temperature T_R2 of the second temperature sensor R2 is lower than the maximum heating temperature T_max. If one of these conditions is not met, i.e. if the temperature T_R1, T_R2 in the cooling buffer tank 10 or in the heating buffer tank 14 has reached the minimum cooling temperature T_min or the maximum heating temperature T_max, the first heat pump 4 is blocked and cannot be activated become. Otherwise, if these conditions are not present, the first heat pump 4 is released for operation.

The desired heating temperature T_Soll,Hz is, for example, in the range between 30° and 60° and in particular in a range from 30° to 45°C and specifically at 35°C. If this falls below, the first heat pump 4 is switched on or, if necessary, the second heat pump 26 is switched on in the heating mode.

The target cooling temperature T_Soll,K is, for example, in the range from 5° to 20°C, specifically in the range from 8° to 18°C and in particular, for example, at 12°C. If this is exceeded, the first heat pump is switched on again 4 or if this is blocked, switching on the second heat pump 26.

In order to achieve the most efficient operation possible, the maximum heating temperature T_max is for example 10° to 30°C, preferably 10° to 20°C and for example 10°C above the heating target temperature T_Soll, Hz. Buffer memory 14 allows up to this maximum heating temperature T_max. Conversely, this also applies to supercooling of the cooling buffer store 10. In this case, the minimum cooling temperature T_min is preferably also, for example, 10° to 15K below the cooling setpoint temperature T_Soll,K and, for example, 5K.

The target temperatures T_Soll,Hz; T_Soll,K are controlled during operation as required, for example as a function of the outside temperature outside the building or as a function of the requirements of an industrial process. At the same time, the desired difference from the maximum and minimum temperatures T_max, T_min is preferably defined, so that the absolute values for these maximum and minimum temperatures are tracked.

In a preferred development, however, the temperature difference between the setpoint temperatures T_Soll,Hz; T_Soll,K and the maximum and minimum temperatures T_max; T_min varies or the absolute values of the maximum or minimum temperatures T_max; T_min varies.

In particular, this variation takes place automatically by means of the control device, which is not shown here, in particular as a function of a current energy price. For example, when night-time electricity is cheap, the temperature difference and/or the maximum values (minimum values) are increased (decreased), so that the degree of loading of the buffer storage tanks 10,14, i.e. their overheating or undercooling, can be increased.

In order to set the desired temperatures at the consumers 12,16, the valves 24 are designed as mixing valves, so that a so-called Return admixture is realized in order to set the respective consumer flow temperature to the required temperature level. These valves 24 (mixer) are also controlled by the control unit.

Consumers 12, 16 are preferably controlled externally, e.g. via a building management system, i.e. the temperature level for consumers 12, 16 is set externally. In principle, more than one consumer (circuit) can be connected to a respective buffer storage 10,14.

In a preferred embodiment, the entire system is designed for mono-energetic operation, so that preferably only an electrical energy supply is provided. The two heat pumps 4.26 are operated with electrical energy. If required, additional electric heating elements can be arranged, for example, in the heating buffer tank 14 in order to ensure an efficient heat supply even at low outside temperatures.

Reference List

2

heat pump arrangement

4

first heat pump

6

cooling circuit

6A

cooling flow

6B

cooling return

8th

heating circuit

8A

heating flow

8B

heating return

10

cooling buffer tank

12

cooling consumer

14

Heating buffer tank

16

heating consumer

18

hot water storage tank

20

pump

24

mixing valve

25

double differential pressureless distributor

26

second heat pump

26A

leader

26B

return

28

supply bypass line

30

return bypass line

32

first multi-way valve

34

second multi-way valve

R1

first temperature sensor

R2

second temperature sensor

T_Soll,Hz

heating target temperature

T_Soll,K

cooling target temperature

T_max

maximum heating temperature

T_min

minimum cooling temperature

T_R1

Temperature at the first sensor R1

T_R2

Temperature at the second sensor R2

Claims (14)

1. Heat-pump installation (2) which is configured for simultaneous heating and cooling, having a heat source and having a heat sink and also having

   - a first heat pump (4), which is in the form of a liquid-liquid heat pump and is connected on a source side to the heat source and on a sink side to the heat sink, wherein

   - the heat source comprises a cooling circuit (6) having a cooling feed (6A), a cooling return (6B), a cooling buffer store (10) for cold water, and, in the connected state, a cooling consumer (12),

   - the heat sink comprises a heating circuit (8) having a heating feed (8A), a heating return (8B), a heating buffer store (14) for heating water, and a heating consumer (16), wherein the heating circuit (8) has, as an alternative or in addition to the heating buffer store (14) and the heating consumer (16), a hot-water store (18),

   - wherein, via the first heat pump (4), a heat displacement between the cooling circuit (6) and the heating circuit (8) is realized during operation such that there is simultaneously provided a cooling power on the side of the cooling circuit (6) and a heating power on the side of the heating circuit (8),

   - there is arranged an auxiliary unit which is connected, in particular hydraulically, to the cooling circuit (6) and to the heating circuit (8), wherein the auxiliary unit is configured both for providing additional heat for the heating circuit (8) and for providing additional cold for the cooling circuit (6),

   - having a control unit for controlling the operation of the heat-pump installation (2), wherein the auxiliary unit is a second heat pump (26) which is in the form of an air-liquid heat pump and which is reversibly operable, so that it can feed heat into the heating circuit (8) in a heating mode and can feed cold into the cooling circuit (6) in a cooling mode.
2. Heat-pump installation (2) according to the preceding claim,
   in which the second heat pump (26) is able to be connected, preferably in terms of flow, to the heating circuit (8) or the cooling circuit (6) via a first multi-way valve (32), wherein the second heat pump (26) is connected to the heating circuit (8) in the heating mode and to the cooling circuit (6) in the cooling mode.
3. Heat-pump installation (2) according to either of the preceding claims,
   in which a feed bypass line (28) connects the cooling feed (6A) to the heating feed (8A) and the second heat pump (26) has a feed (26A) which, via the first multi-way valve (32), is connected, preferably in terms of flow, to the cooling feed (6A) in the cooling mode and to the heating feed (8A) in the heating mode.
4. Heat-pump installation (2) according to one of the preceding claims,
   in which a return bypass line (30) connects the cooling return (6B) to the heating return (8B) and the second heat pump (26) has a return (26B) which, via a second multi-way valve (34), is connected, preferably in terms of flow, to the cooling return (6B) in the cooling mode and to the heating return (8B) in the heating mode.
5. Heat-pump installation (2) according to one of the preceding claims,
   in which the control unit is configured in such a way that the first heat pump (4) has priority over the auxiliary unit (26) and is blocked for operation only if a maximum heating temperature (T_max) in the heating buffer store (14) or a minimum cooling temperature (T_min) in the cooling buffer store (10) has been reached.
6. Heat-pump installation (2) according to one of the preceding claims,
   in which the control unit is configured in such a way that the auxiliary unit (26) is activated only if a heating target temperature (T_Soll,Hz) in the heating buffer store (14) has been fallen below or a cooling target temperature (T_Soll,K) in the cooling buffer store (10) has been exceeded.
7. Heat-pump installation (2) according to the preceding claim,
   in which the control unit is configured in such a way that the auxiliary unit is deactivated if the heating target temperature (T_Soll,Hz) in the heating buffer store (14) has been exceeded or the cooling target temperature (T_Soll,K) in the cooling buffer store (10) has been fallen below.
8. Heat-pump installation (2) according to the preceding claim,
   in which the heating target temperature (T_Soll,Hz) lies in a range from 30°C to 60°C and in particular in a range from 30°C to 45°C and the cooling target temperature (T_Soll,K) lies in a range from 5°C to 20°C and in particular in a range from 8°C to 18°C.
9. Heat-pump installation (2) according to Claims 5 and 6 or 7 or 8, in which a temperature difference between

   - the maximum heating temperature (T_max) and heating target temperature (T_Soll,Hz) lies in the range between 5 and 25 K, in particular 10 and 15 K, and/or

   - the minimum cooling temperature (T_min) and cooling target temperature (T_Soll,K) lies in the range between 5 and 20 K, in particular 8 and 12 K.
10. Heat-pump installation (2) according to Claims 5 and 6 or according to Claim 7, 8 or 9, in which the difference between the heating target temperature (T_Soll,Hz) and the cooling target temperature (T_Soll,K) lies in the range from 10 to 40 K, in particular in the range from 15 to 35 K.
11. Heat-pump installation (2) according to one of the preceding claims,
    in which the control unit is configured in such a way that the auxiliary unit is activated in an auxiliary operating mode only if the first heat pump (4) is blocked for operation.
12. Heat-pump installation (2) according to one of the preceding claims,
    in which the control unit is configured in such a way that the auxiliary unit is activated in addition to the first heat pump (4) in an assistance operating mode.
13. Heat-pump installation (2) according to one of the preceding claims,
    in which the heating and cooling power of the first heat pump (4) is lower than heating and cooling power of the auxiliary unit and preferably amounts to merely 80% or merely 50% of the heating and cooling power of the auxiliary unit.
14. Heat-pump installation (2) according to one of the preceding claims and according to Claims 5 and 6, in which the control unit is configured in such a way that, during the operation of the heat-pump installation,

    - the minimum cooling temperature (T_min) or the maximum heating temperature (T_max) or alternatively

    - a temperature difference between the minimum cooling temperature (T_min) or the maximum heating temperature (T_max) and the respective target temperature is automatically varied, wherein the control unit is preferably furthermore configured in such a way that the variation is realized in a manner dependent on a presently surplus energy supply or a present energy price.

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