Installation for heat supply to a building and method of operation

Abstract

The system for supplying heat to a building comprises, in addition to an outside air heat exchanger (11), a fan device (12) for conveying outside air through the outside air heat exchanger (11), a latent heat storage unit (13) with a closed tank (18) and a heat pump (15), a piping system (16) filled with a liquid working medium and a pumping device (17) for conveying the working medium through the piping system. The piping system (16), the pumping device (17), the outdoor air heat exchanger (11), the heat pump (15) and the latent heat storage unit (13) form a closed circuit for the working medium and are arranged such that the working medium flows through the outdoor air heat exchanger (11), the latent heat storage unit (19) and an evaporator heat exchanger (21) of the heat pump (15) in the closed circuit in this sequence before being returned to the outdoor air heat exchanger (11).

Description

[0001] The invention relates to the field of heat supply for buildings, i.e., building heating and / or the provision of hot water. It relates in particular to a system for the heat supply of a building and an operating method for such a system.

[0002] Heat pump heating systems include, in addition to water-to-water heat pumps (which extract heat from groundwater and are only suitable under specific circumstances), systems with heat exchangers in the ground (so-called ground source heat pump systems) and systems with outside air heat exchangers, which use the ambient air as a heat source. The latter require significantly less investment than ground source heat pump systems but have the disadvantage of lower efficiency. This lower efficiency is particularly noticeable when outside temperatures are low and the demand for heating energy is therefore especially high. Another disadvantage of heat pump systems with outside air heat exchangers is the considerable noise pollution, which results from the fact that a fan must constantly circulate air through the outside air heat exchanger when the heat pump is operating – especially at night.

[0003] To overcome these disadvantages, the use of ice storage systems has already been proposed, for example in EP 2614330 A1, EP4 033 163 A1, EP 4 141 322 A1, and DE 10 2013 213 823 A1. In such an ice storage system, a heat exchanger extracts heat from an ice storage unit during the heating season until the unit is thermally discharged. At thermal discharge, a predetermined volume around the heat exchanger freezes completely. This occurs in a controlled manner. The water around the heat exchanger tubes of the heat exchanger freezes selectively from the inside out. To recharge the ice storage unit, heat, particularly from the outside air, is introduced into the unit via a regeneration heat exchanger after the heating season. This process also causes the ice around the heat exchanger to thaw in a controlled and directed manner.In conventional ice storage systems, the hydraulic circuits for extraction and regeneration must be strictly separated to prevent uncontrolled thawing or freezing, which would render the ice storage system uncontrollable or, in the worst case, damage or even destroy the heat exchanger tubes through ice spalling. This results in considerable complexity.

[0004] EP4033163 A1 proposes closing the regeneration circuit in an ice storage system to the heat pump and allowing the fluid circulating from the outdoor heat exchanger to flow in reverse through the latent heat storage unit. This has the advantage of tending to avoid the aforementioned problems of uncontrolled thawing or freezing, but also entails considerable complexity with a large number of switched valves.

[0005] In DE 10 2013 213 823 A1, the ice storage system is regenerated by two methods: firstly, by passing wastewater through a wastewater pipe running through the ice storage system, and secondly, by a heat pump supplying heat to the ice storage system during the summer. A pressure equalization tank is required to prevent the water pipe from bursting when the water freezes.

[0006] Besides their complexity, ice storage systems, according to the state of the art, also have the disadvantage of requiring a large amount of space so that the ice storage is large enough to store heat for the heating season during the warmer months.

[0007] Based on this prior art, the present invention aims to provide a system with an outdoor air heat exchanger for supplying heat to a building, which overcomes the disadvantages of the prior art and utilizes the advantages of heat pump systems with outdoor air heat exchangers, while avoiding or at least reducing their disadvantages. A further objective is to provide a corresponding operating procedure.

[0008] These tasks are solved by a system and a method as defined in the independent patent claims.

[0009] The building heating system, as is known per se, comprises an outside air heat exchanger and a fan for circulating outside air through the heat exchanger. It also includes a latent heat storage system, a heat pump, a piping system filled with a liquid working fluid, a pump for circulating the working fluid through the piping system, and a control system for controlling the pump, the fan, and the heat pump. The latent heat storage system has a closed tank for holding a storage medium—for example, water—which is in a liquid and / or solid state during operation. That is, depending on how much the latent heat storage system is charged or discharged, a larger or smaller proportion of the storage medium is in a liquid state.

[0010] The fact that the tank containing the storage medium is closed means that it has a defined volume and is also closed at the top, so that the storage medium cannot become uncontrollably contaminated and large quantities of it cannot evaporate. However, it is possible that the tank may have one or more small openings, for example, for pressure equalization with the environment; that is, it does not have to be airtight and it may optionally include an access point for adding and removing storage medium. It is also possible, of course, that the tank can be opened, for example, by having a removable or hinged lid.

[0011] The tank is particularly lightproof to prevent algae growth if the storage medium is, for example, water.

[0012] In addition to the tank, the latent heat storage system has a latent heat storage heat exchanger located inside the tank for the exchange of heat between the storage medium and the working medium.

[0013] The piping system, pump unit, outdoor air heat exchanger, heat pump, and latent heat storage unit are interconnected in the system to form a closed loop for the working fluid – for example, a brine solution. The loop is configured so that the working fluid flows sequentially, in this order, through the outdoor air heat exchanger, the latent heat storage heat exchanger, the heat pump – specifically, an evaporator heat exchanger of the heat pump – and then back through the outdoor air heat exchanger.

[0014] In latent heat storage systems (sometimes referred to as 'ice storage systems' when the storage medium is water), according to the state of the art, separate circuits are provided for extracting heat from the latent heat storage system (thermal discharge of the storage) and for regenerating the latent heat storage system by supplying thermal energy. In some cases, for example in the aforementioned EP4033163 A1, it is also proposed to allow the working medium to flow through the latent heat storage system in reverse for regeneration. The approach proposed here, however, provides that the working medium first flows through the outside air heat exchanger and then through the latent heat storage system heat exchanger. This has significant advantages.Firstly, during normal heating operation – when the heat pump is running; 'normal operation' – the working fluid can be preheated somewhat by the outside air heat exchanger before entering the latent heat storage heat exchanger under almost all weather conditions. Therefore, less energy needs to be extracted from the latent heat storage for heating. For regeneration operation, the working fluid can flow through the same route, first through the outside air heat exchanger and then through the latent heat storage heat exchanger to regenerate it. The resulting simplicity of the design is a further advantage of this approach: for example, a single pump for the working fluid can suffice, used for both heating and regeneration operation. Furthermore, no actively switched diverter valves are required to switch between normal operation (heat pump running and extracting heat from the working fluid) and regeneration operation.Both reduce investment costs and susceptibility to repairs compared to more complex solutions, and simplify regulation and maintenance without any significant disadvantages in terms of efficiency.

[0015] One characteristic of the system described and defined in this text is that it is designed to allow the latent heat storage heat exchanger to flow through in the same direction during regeneration as during normal operation.

[0016] As is typical for heat pumps, the evaporator heat exchanger of a heat pump serves to extract heat from the working fluid in order to evaporate a heat pump fluid on the cold side of the heat pump. The term "evaporator heat exchanger" does not, of course, preclude the possibility of operating the heat pump in reverse, particularly in a cooling mode, which is also possible in summer. In such a reverse operation, the evaporator heat exchanger acts as a condensation heat exchanger, through which heat is removed from the heat pump fluid via condensation and transferred to the working fluid.

[0017] It can be specifically designed so that the evaporator heat exchanger is also supplied with working fluid during regeneration mode, even when the heat pump is not in operation, i.e., when its compressor is not running and the heat pump fluid is not circulating. This can be the case, in particular, under the aforementioned condition that the system is free of actively switched changeover valves for switching between normal operation and regeneration mode, which allows for a particularly simple design.

[0018] In particular, the system can be set up so that the working medium takes the same path on the closed circuit in normal operation (with the heat pump running; heating operation) and in regeneration operation.

[0019] The system control can be programmed and configured in such a way that the fan is not operated, or is operated only with limited fan power, essentially silently, at night and / or during other periods of increased sensitivity to ambient temperature. In this way, the inventive approach can overcome one of the biggest disadvantages of heat pump systems with an outdoor air heat exchanger: The demand for heat supply is often particularly high at night, when outdoor temperatures are low, and especially in the early morning hours when night setback is ending and hot water needs to be produced. To provide the necessary heat output, such a heat pump system must be operated at high fan power for the outdoor air heat exchanger at these times, which is associated with noise emissions. Such noise is known to be particularly undesirable during quiet hours at night.Nevertheless, according to the state of the art, the efficiency of the heat pump is particularly unfavorable with such a procedure due to the generally lower nighttime and early morning air temperatures.

[0020] For example, the system control can ensure that the fan system generally produces a sound power level L WA outdoors according to the ErP label in dB(A) of no more than 42 dB(A), in particular no more than 40 dB(A), and a corresponding sound power level of no more than 38 dB(A) during night operation.

[0021] The inventive approach allows the operating times of the heat pump and the fan to be independent of each other. This means the heat pump can run at night and in the early morning hours, providing a desired high heat output, while the fan runs not at all or only at low fan speed, i.e., quietly. This operating mode automatically ensures that a larger portion of the heat output is drawn from the latent heat storage. During the day, for example, when the outside temperature is somewhat higher, the working fluid can be circulated through the outside air heat exchanger, while the fan operates at a higher fan speed – both when the heat pump is running and when no heat output is being drawn. In the latter case, operation serves exclusively to charge the latent heat storage.of regeneration. The inventive method thus allows noise emissions to be scheduled for those times of day when they are most acceptable.

[0022] In other words, the system control can be programmed to differentiate between night-time and day-time operation depending on the time of day. During night-time operation, the heat pump is switched on as needed, with the fan speed of the ventilation system limited (specifically to a lower value than the maximum fan speed available during the day), even when the heat pump is running. At least during day-time operation, the working fluid is also pumped through the circuit and the ventilation system is operated, at least intermittently, even when the heat pump is not running.

[0023] The fan speed of the ventilation system can be adjusted depending on the time of day and the outside temperature. For example, it may be designed to operate at a relatively high speed during the daytime in colder weather when the outside temperature is higher than the temperature of the storage medium – e.g., 0°C. Depending on requirements, the fan speed may also be reduced at midday, on Sundays and / or other days of rest, and / or when the ambient noise level falls below a certain threshold.

[0024] In addition to or as an alternative to differentiating between daytime and nighttime operation, noise-level-dependent operation can also be implemented, for example, at least on days when the system is closed. For this purpose, the system can have at least one noise sensor that measures the noise level in the surrounding area. Generally, one noise sensor can be located in the vicinity of the building (but at a sufficient distance from the fan unit so that fan noise does not influence the noise level measurement), and optionally, an additional noise sensor can be located near the fan unit. However, the latter can be omitted if the noise emissions of the fan unit as a function of its performance are already known, for example, based on reference measurements and / or simulations.

[0025] As indicated, the latent heat storage can in particular be an ice storage system, i.e., the storage medium can be water.

[0026] Prior art latent heat storage systems, which are primarily used to store heat during the warmer months for use during the colder months, must be correspondingly large to be effective. Their space requirements are also correspondingly large. In contrast, the inventive method makes latent heat storage systems with significantly smaller tank dimensions practical. For example, the tank size (defined by the volume of the intended tank capacity) can be less than 2 m³ in some embodiments, e.g., a maximum of 1,500 liters, or even 1,200 liters or less. Such a compact tank can be located in a garage, laundry room, or basement – ​​or it can be buried in a small garden. Furthermore, it can absorb some heat from the surroundings via its surface, which can ultimately contribute to the heating output if the tank is located in an unheated part of the building, e.g., a basement.the garage, or in the garden.

[0027] The tank can be made of plastic, for example, black (black-dyed) plastic. It can, in particular, be designed as a molded plastic part.

[0028] The latent heat storage heat exchanger is, in particular, the only heat exchanger in the latent heat storage system, meaning that a separate heat exchanger for regenerating the storage medium is not required – which favors the simple design discussed at the beginning, with a single working fluid circuit that serves both for supplying heat to the cold side of the heat pump and for regenerating the latent heat storage system.

[0029] A common issue with heat pump-based systems using an outdoor air heat exchanger is defrosting the outdoor air heat exchanger when it ices up. If the outdoor temperatures are not high enough to defrost the outdoor air heat exchanger simply by running the fan – without any working fluid being pumped through it – or if there isn't enough time for this, there are two state-of-the-art solutions. The first solution uses an electric resistance heater. The second involves operating the heat pump in reverse, using the evaporator heat exchanger as the condenser heat exchanger, while extracting heat from the hot side – ultimately, the heated object or the thermal storage unit used for heating. The first solution is not very energy-efficient and results in high electricity consumption during the defrosting process.The second option also involves substantial electricity consumption during the defrosting process and is also complex and involves substantial additional costs.

[0030] Against this background, a defrosting circuit is proposed in a group of embodiments of the present invention. This circuit provides a first branch from the closed circuit for the working fluid downstream of the outlet of the outside air heat exchanger and upstream of the inlet to the evaporator heat exchanger of the heat pump, and a second branch between the outlet of the evaporator heat exchanger and the inlet to the outside air heat exchanger, wherein (at least) one of these branches is switchable, in particular by being designed as a diverter valve. This allows the working fluid to be selectively routed either through the evaporator heat exchanger or through a branched bypass from the first branch to the second branch. The first branch and the second branch are positioned such that the pump of the closed circuit is supplied with fluid in both operating states, i.e.,This applies both when the working fluid passes through the evaporator heat exchanger and when it passes through the heating section, so that a single pump is sufficient for both the aforementioned closed circuit and the defrost circuit that is formed when the evaporator heat exchanger section is replaced by the heating section. In other words, the pump is positioned downstream of the second branch and upstream of the first branch in the direction of flow.

[0031] In particular, the first branch can be designed as a diverter valve and the second branch as a T-piece.

[0032] Between the first branch and the second branch, the working fluid flows through the secondary (cold) side of a defrost heat exchanger, e.g., a plate heat exchanger, on the heating section. The primary side of this heat exchanger is flowed through by the heating medium, specifically downstream of the condenser heat exchanger of the heat pump. In other words, the primary side of the defrost heat exchanger is located downstream of the condenser heat exchanger of the heat pump in the flow direction. A buffer storage tank may be present in between, since the heat pump generally does not run during defrosting because the evaporator heat exchanger is not being used. Therefore, in simple embodiments of this group of embodiments (with only one pump as described), simultaneous operation of the defrost circuit and the heat pump is not possible.

[0033] For defrosting operation, the working medium flows from the first branch into the defrosting heat exchanger, where it is heated, from there to the second branch and then through the external heat exchanger, which is thus defrosted.

[0034] Advantages of this approach, as described in this group of embodiments, include low installation costs, high energy efficiency, especially with short pipe runs, and the fact that defrosting does not cause a sudden increase in electricity consumption, since no electrical energy is required except for that needed to operate the pump. The defrosting process is nevertheless fast because the working fluid in the defrost heat exchanger is heated to a relatively high temperature. Furthermore, as with the second prior art option mentioned earlier, the heat energy required for defrosting is recovered after the heat pump, resulting in a COP advantage. In the illustrated design, the pressure drop through the defrost heat exchanger also only occurs during defrosting operation.

[0035] The system can be modular. Modular means that the system control is designed to be configured to accommodate more than one latent heat storage unit (each with a tank and latent heat storage heat exchanger) and / or more than one outdoor air heat exchanger with an associated fan. In particular, the system control can support multiple latent heat storage units and / or outdoor air heat exchangers arranged in parallel and / or possibly in series. Even with more than one latent heat storage unit and / or more than one outdoor air heat exchanger, optionally only a single circuit is required; for example, a single pump is sufficient, and / or the system can operate without actively switched diverter valves.

[0036] In a parallel arrangement of several latent heat storage units and / or several outdoor air heat exchangers, portions of the working fluid flow through each of the latent heat storage units or outdoor air heat exchangers. The circuit can be designed so that it still requires only a single pump and no actively switched diverter valves – if the flow resistance through the various latent heat storage units or outdoor air heat exchangers is approximately the same, a roughly equal flow rate through the latent heat storage units or outdoor air heat exchangers is automatically established.

[0037] The inventive method, which enables a latent heat storage system with a relatively small tank and allows the use of off-the-shelf outdoor air heat exchanger modules (outdoor air heat exchangers with fan devices) known from air source heat pump systems, promotes this modularity: If the heating output is insufficient when only one latent heat storage system and / or only one outdoor air heat exchanger is present, one or more additional such elements can simply be added without having to redesign the entire system.

[0038] In addition to the system for supplying heat to a building, the invention also relates to an operating method in which the working fluid circulates on the aforementioned closed circuit and absorbs heat from the outside air in the outdoor air heat exchanger before entering the latent heat storage heat exchanger, where, depending on the temperature, it either absorbs further heat or releases heat to the latent heat storage heat exchanger for regeneration before entering the evaporator heat exchanger of the heat pump. In this heat exchanger, depending on the operating state of the heat pump, it serves to evaporate a heat pump fluid – or it simply flows through the heat pump. It then returns to the outdoor air heat exchanger.

[0039] The process can be implemented in such a way that, in heating mode, the heat pump runs and the working fluid in the evaporator heat exchanger causes a heat pump fluid to evaporate, while in regeneration mode the fan and pump systems run, even though the heat pump is switched off. It can also be provided that the working fluid flows through the evaporator heat exchanger of the heat pump even in regeneration mode, although the heat pump is not running at all – thus enabling the simplification in design and control already described above.

[0040] The procedure can be implemented in such a way that the system control ensures that the maximum fan power of the fan unit is lower during night operation than during day operation – that is, at night, e.g. at pre-programmed times, a power limit for the fan unit can apply regardless of the heating power requirement, which is stricter than a power limit for day operation.

[0041] In general, the fan power of the fan system can be selected depending on the time of day and / or a measured noise level as well as the outside temperature and possibly a storage state of the latent heat storage (temperature, proportion of frozen storage medium) - and not, or not primarily, as is known from the prior art, on the operating state of the heat pump and / or the heat demand of the building.

[0042] Exemplary embodiments of the invention are described below with reference to the figures. In the figures, identical reference numerals denote identical or analogous elements. The figures show: Fig. 1 A schematic of a system for supplying heat to a building; Fig. 2 The sound level as a function of the time of day near the outside air heat exchanger of a system operated similarly to a heat pump system according to the state of the art; Fig. 3 A Fig. 2 analogous representation for a properly operated plant of the in Fig. 1 of the type shown; and Fig 4 a scheme of a variant of the system for the heat supply of a building, with defrosting circuit.

[0043] The system 1 for the heat supply of a building 41 has an outdoor air heat exchanger module, which includes an outdoor air heat exchanger 11 and a fan unit 12. The fan unit is configured to convey outdoor air through the outdoor air heat exchanger 11 in order to supply the inlet side (in the illustration according to Fig. 1 (top side) to warm up a cold, liquid working medium.

[0044] The system has a piping system 16 which forms a circuit for the working medium and which has a pump 17 which pumps the working medium unidirectionally through the circuit.

[0045] Following the outside air heat exchanger 11 in the direction of the working medium flow is the latent heat storage unit 13, with a tank 18 containing the latent heat storage heat exchanger 19, which is filled with a storage medium, e.g., water. Depending on the storage state, the storage medium is liquid and / or solid – the more discharged the latent heat storage unit is, the higher the proportion of the storage medium in the solid state. Therefore, if the storage medium is water, ice forms inside the tank 18.

[0046] Following the latent heat storage heat exchanger 19, the working fluid flows through an evaporator heat exchanger 21 of the heat pump 15. When the heat pump 15 is operating, a heat pump medium (the medium circulating in the heat pump is referred to in this text as the "heat pump medium"; it may have a different, the same, or a similar composition compared to the working fluid) is evaporated at low pressure in the evaporator heat exchanger 21 of the heat pump in a heat pump circuit. As is known per se, the heat pump 15 also has a condenser heat exchanger 22. When the heat pump is running, its compressor pumps the evaporated heat pump medium under pressure to the condenser heat exchanger 22, where it condenses and releases heat to the condenser heat exchanger 22 before returning to the evaporator heat exchanger 21 via an expansion valve.

[0047] The working fluid returns from the evaporator heat exchanger 21 to the outside air heat exchanger 11.

[0048] The heat transferred to the condenser heat exchanger can be used to supply heat to building 41. The elements and circuits connected to the hot side of the heat pump can be designed for this purpose in a manner known per se and can be taken from existing building heating and hot water supply systems – depending on the situation, either pre-installed systems or systems specifically installed during the installation of the inventive system. In the illustrated embodiment, a further heat storage circuit of a heat medium with a heat storage unit 23, e.g., with a boiler for hot water supply, is provided, as well as, branching off from this, a heating circuit for circulating this heat medium through radiators, floors, walls, and / or ceilings of the building for its heating.In the illustrated embodiment, the heat storage circuit and the heating circuit are equipped with a common circulation pump 42, and the heating circuit is provided with an additional heating pump 43. A T-piece 44 allows switching between different operating modes by selecting the operating states of the circulation pump 42 and the heating pump 43, whereby the heat delivered by the heat pump can be used directly for building heating or for charging the heat storage tank 23, or the heat stored in the heat storage tank can be used for building heating. However, the design of the building heating and / or hot water supply is not the subject of the present invention. The building heating and hot water supply can also be implemented in other configurations than the one illustrated.

[0049] Depending on the design of the building services (especially the building heating system), the heat pump can be configured to operate in reverse during the summer. This means the heat pump circuit can be switched or reconfigured so that, in this summer mode, the evaporator heat exchanger 21 is located after the compressor and the condenser heat exchanger 22 is located after the expansion valve. This allows the evaporator heat exchanger 21 to function as a condenser and the condenser heat exchanger 22 as an evaporator. In this optional summer mode, heat can be extracted from the building and transferred to the working fluid for building cooling. The heat can then be dissipated via the outside air heat exchanger and / or, if necessary, the latent heat storage tank 13 can be regenerated.

[0050] The system controller 31 is set up and programmed to control the pump 17, the fan unit 12, and the heat pump 15. The corresponding communication link with these components, as well as with any sensors, is in place. Fig. 1 The sensors are only indicated by a double arrow. For example, in addition to an outdoor temperature sensor, the sensors also include one each in Fig. 1 The temperature sensor is symbolically represented on the inlet and outlet sides of the heat pump, as well as between the outside air heat exchanger 11 and the latent heat storage tank 13. At least one further temperature sensor is located inside the latent heat storage tank 13. The system control can be in communication with a heat supply control unit 32, which controls the building's heat supply, or be integrated with it in a common control unit; that is, the system control unit 31 and the heat supply control unit 32 do not have to form separate units, either physically or programmatically.

[0051] In the illustrated embodiment, the system also includes a noise sensor 51 for detecting a noise level in the vicinity of the building and a noise sensor 52 for detecting a noise level directly at the fan unit. These two noise sensors 51 and 52 are in communication with the system controller 31, which can, for example, depending on the time of day (e.g., during night operation), control the fan unit 12 so that the noise level in its immediate vicinity is in a predefined relationship to the noise level in the vicinity of the building, e.g., not exceeding it by more than a predefined decibel level. The noise sensors are optional; and it may also be practical to use only one noise sensor 51 to detect a noise level in the vicinity, without an additional noise sensor 52 at the fan unit.

[0052] Regardless of whether a noise sensor is present or not, the system can be operated in such a way as to reduce noise emissions and optimize their timing. This will be demonstrated using the following examples: Figuren 2 und 3 shown, which represent the sound power level as a function of the time over a 24-hour period.

[0053] Fig. 2 shows a recording of the sound power level LWA in the immediate vicinity of the outdoor air heat exchanger module (outdoor air heat exchanger with fan unit) of a system located in Fig. 1 The depicted type occurs when the system is operated in the manner of a conventional air-to-water heat pump system, that is, with the typical start-up characteristics of an air-source heat pump system, in which the outdoor heat exchanger's fan operates during the heat pump's operating times and the outdoor air heat exchanger must provide sufficient heat for this purpose. Measurements were taken using a PeakTech sound level meter positioned approximately 0.5 m from the fan. It can be seen that whenever the control system apparently detects a heat demand, the heat pump system is activated, which is associated with noise emissions that can significantly exceed 60 dB(A) on average during these "on" periods, which is perceived as loud. These "on" periods are distributed throughout the day, including the night and especially the early morning when the heat demand is particularly high.

[0054] In contrast, the in Fig. 3 The analog recording shown was made with the same system as in Fig. 1 as shown and with the same measurement parameters. [It can be seen that the system control provides for daytime operation, with a switch-on time (72) shortly before 8 a.m. and a switch-off time (73) at approximately 6 p.m. During daytime operation, the fan runs at a relatively high power and causes noise emissions of approximately 50 dB(A), which is still significantly lower than the sound power level generated by the outdoor air heat exchanger module of the prior art heat pump system during its 'on' times. This is achieved by distributing the emissions well over time, even during daytime operation, by operating the fan independently of the heat pump activity. In general, the outdoor temperature is also higher during daytime operation, meaning the outdoor air heat exchanger module operates more efficiently than at night.]After the shutdown time of 73, the fan system switches to night mode, during which it operates in a whisper mode with reduced fan power. This mode lasts until the following morning when it switches back to daytime operation. The short-term peaks visible in the measurements are due to ambient noise from the surroundings that are unrelated to the operation of the system, such as birdsong or passing vehicles.

[0055] Even though the overall heat absorption of the heat pump system from the outside air was comparable in both cases, the comparison of the Fig. 2 with the Fig. 3 However, the advantages of the inventive method are clearly evident, as the overall noise pollution is reduced and also occurs at a more optimized time when the advantages of the inventive system are utilized. Furthermore, electricity consumption is also reduced on average, as the temperatures on the cold side of the heat pump are on average higher, the power consumption of the fan is reduced, and the likelihood of having to activate an electric emergency heater at very cold outside temperatures below -7°C is decreased.

[0056] The system control unit 31 is therefore specifically designed (programmed and configured) so that the fan speed is not, or not primarily, high when the heat pump is running due to a building's heating demand. Instead, the times at which the working fluid is circulated, and in particular the fan speed, are selected based on other parameters, namely the time of day and / or a measured noise level, and the outside temperature (an outside temperature sensor 61 is schematically shown in Fig. 1 (drawn, along with a plurality of symbolically represented temperature sensors along the closed circuit of the working fluid and the circuits of the heat medium), and, for example, a storage state of the latent heat storage, namely its temperature and / or proportion of frozen storage medium. A measure of the temperature of the storage medium and of its state in general is also the easily measurable difference between the temperature of the working fluid before and after the storage medium.

[0057] Figur 4 shows a variant of the system of Fig. 1 , whereby the system control and the heat supply control are not illustrated, nor are any heating circuits or noise sensors shown; it is understood that these elements will also be present or at least may be present (in particular the noise sensors are optional).

[0058] In the version of Fig. 4The closed circuit for the working fluid is not entirely free of branches, although in this variant the working fluid flows along the same path during normal operation and regeneration. Rather, the system features an electronically controlled diverter valve 81, which is located between the pump 17 and the heat pump 15. Furthermore, a T-piece 85 is present, which is located between the working fluid return line of the heat pump and the outside air heat exchanger 11. The diverter valve 81, together with the T-piece 85, serves to branch off a heating section, through which, together with the partial circuit from the T-piece via the outside air heat exchanger 11, the latent heat storage heat exchanger 19, and the pump 17, a defrosting circuit is formed.

[0059] Generally, depending on the switching state of the changeover valve 81, either the closed circuit via the heat pump 15 (more precisely: the evaporator heat exchanger 21 of the heat pump) or the defrost circuit is active, but not both. In the arrangement shown, the pump 17 of the closed circuit via the heat pump also serves as the pump for the defrost circuit. The heating section includes a defrost heat exchanger 83, for example, a plate heat exchanger. It also has a first defrost circuit line 82 and a second defrost circuit line 84. The working fluid, pumped by the pump 17, flows through the first defrost circuit line 82 to the secondary side of the defrost heat exchanger 83, where it is heated. From there, it flows via a second defrost circuit line 84 and the T-piece 85 back to the inlet side of the outside air heat exchanger 11 to defrost it as needed.

[0060] The primary side of the defrost heat exchanger 83 is traversed by a heat transfer medium. In the illustrated embodiment, the heat storage circuit has no branching, so that the heat transfer medium flows through the primary side of the defrost heat exchanger 83 regardless of the operating state when the circulation pump 42 is in operation. Since the heat pump 15 does not run during the defrosting process because the working medium does not flow through it, the heat required for defrosting comes from the heat storage circuit, in particular from a buffer storage tank between the outlet of the heat pump 15 and the defrost heat exchanger 83 (not shown).

[0061] The switching valve 81 should be designed in embodiments such that it is also suitable for the working medium (a brine, depending on the embodiment) and that it remains functional even at temperatures significantly below 0°C.

Claims

1. A system for supplying heat to a building, comprising an outdoor air heat exchanger (11), a fan assembly (12) for conveying outdoor air through the outdoor air heat exchanger (11), a latent heat storage system (13), a heat pump (15), a piping system (16) filled with a liquid working medium, a pump assembly (17) for conveying the working medium through the piping system, and a system control unit (31) for controlling the pump assembly (17), the fan assembly (12) and the heat pump (15), wherein the latent heat storage system (13) includes a closed tank (18) for receiving a liquid and / or solid storage medium and a latent heat storage heat exchanger (19) arranged in the tank (18), characterized by the fact thatthe piping system (16), the pumping device (17), the outdoor air heat exchanger (11), the heat pump (15) and the latent heat storage unit (13) form a closed circuit for the working medium and are arranged so that the working medium flows through the outdoor air heat exchanger (11), the latent heat storage unit heat exchanger (19) and an evaporator heat exchanger (21) of the heat pump (15) in the closed circuit in this sequence before it is returned to the outdoor air heat exchanger (11).

2. System according to claim 1, wherein the system control (31) is set up and programmed such that the fan system operates with limited fan power at night and / or at low ambient noise levels.

3. System according to claim 1 or 2, wherein the system control (31) is set up and programmed such that the pump device (17) and the fan device (12) are active at least temporarily in a regeneration mode even when the heat pump (15) is not in operation and the outside air is warmer than the storage medium.

4. System according to claim 3, which is configured such that the evaporator heat exchanger (21) is also supplied with working fluid when the heat pump (15) is not in operation and when the pump device (17) and the fan device (12) are active in regeneration mode.

5. System according to one of the preceding claims, wherein the circuit is free of branches.

6. Plant according to one of the preceding claims, wherein the tank (18) has a capacity of at most 1500 l, in particular at most 1200 l.

7. System according to one of the preceding claims, comprising a noise sensor (51) for detecting a noise level in the environment of the building, wherein the system control (31) is configured to adjust the power of the fan device to the noise level.

8. System according to one of the preceding claims, wherein the latent heat storage heat exchanger (19) is the only heat exchanger inside the tank (18).

9. System according to one of the preceding claims, wherein the system control is configurable to support more than one latent heat storage unit (13) and / or more than one outdoor air heat exchanger (11).

10. System according to claim 9, wherein the system control is configurable to support more than one latent heat storage device (13) arranged in parallel to each other in a closed circuit.

11. System according to one of the preceding claims, wherein the closed circuit has a first branch (81) between an outlet of the outside air heat exchanger (11) and before an inlet to the evaporator heat exchanger (21) and a second branch (85) between an outlet of the evaporator heat exchanger (21) and an inlet to the outside air heat exchanger (11), wherein the system is configured to selectively direct the working medium between the first branch and the second branch either through the evaporator heat exchanger (21) or via a heating section, wherein the heating section has a defrost heat exchanger (83) through which the working medium can absorb heat from a heat medium heated by the heat pump (15).

12. Method for operating a plant according to one of the preceding claims, wherein the working medium circulates on a closed circuit, such that the working medium on the closed circuit successively flows through the outdoor air heat exchanger (11), the latent heat storage heat exchanger (19), and an evaporator heat exchanger (21) of the heat pump (15) in this sequence before being returned to the outdoor air heat exchanger (11).

13. Method according to claim 12, wherein the system control controls the pump device (17), the heat pump (15) and the fan device (12) such that in heating mode the heat pump (15) runs and the working medium in the evaporator heat exchanger (21) causes evaporation of a heat pump medium and in regeneration mode the fan device (12) and the pump device run while the heat pump is switched off.

14. Method according to claim 12 or 13, wherein the system control controls the fan device (12) such that the maximum fan power during night operation is lower than during day operation.

15. Method according to one of claims 12-14, wherein the system control controls the fan device (12) such that the fan power depends on the time of day and / or a measured noise level as well as on the temperature of the outside air and a storage state of the latent heat storage.

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