Heating system and methods for operating a heating system

Abstract

The invention relates to a heating system (10) with at least one collector (16), in particular a PVT collector (18), and with a heat pump (30) installed in a room (12) with a refrigerant circuit (38) in which a refrigerant (40) circulates, and which has at least one heat exchanger (28), at least one compressor (42) and at least one expansion device (44), wherein the heat exchanger (28) of the heat pump (30) is capable of exchanging heat with the collector (16), in particular the PVT collector (18). It is proposed to provide a device (52) that is capable of supplying outside air (54) to the heat pump (30). The invention also relates to a method for operating such a heating system.

Description

Technical area

[0001] The present invention relates to a heating system with at least one collector and with a heat pump State of the art

[0002] DE102012019525A1 discloses a heating system in which a solar collector, in particular a PVT module, works together with a heat pump. Disclosure of the invention

[0003] The heating system according to the invention, comprising at least one collector, in particular a PVT collector, and a heat pump installed in a room with a refrigerant circuit in which a refrigerant circulates, and which has at least one heat exchanger, at least one compressor, and at least one expansion device, wherein the heat exchanger of the heat pump is capable of exchanging heat with the collector, in particular the PVT collector, is characterized by a device capable of supplying outside air to the heat pump. This ensures that icing of the heat pump or certain components thereof can be avoided or at least reduced.

[0004] A collector is primarily understood to be a solar collector that converts solar energy into heat and can feed it into a system. However, alternative systems such as geothermal heat exchangers or deep-hole heat exchangers are also conceivable. A PVT collector is a photovoltaic-thermal hybrid solar collector that can generate both thermal energy and electrical energy from solar energy. Outside air refers to air that is not provided from the room in which the heat pump or the components prone to icing are located.

[0005] The features listed in the subclaims enable advantageous developments of the heating system according to claim 1. This provides a simple way of controlling the heating system if a control unit is provided which is designed to control or regulate the amount of outside air supplied depending on the current temperature and / or the current relative humidity of the supplied outside air. The amount of outside air is thus individually adjusted to the temperature, so that in particular not too much possibly cool outside air gets into the room in which the heat pump is installed. If the outside air is blown directly into a housing surrounding the heat pump, a differential pressure between the pressure inside this housing and an ambient pressure and / or a value characterizing the lowest temperature inside the housing can also be used as control parameters.

[0006] Controlling is understood here as influencing an output variable based on an input variable. Controlling is understood as influencing an output variable based on an input variable, with the effect being fed back to the output variable and fed back into the control system along with the input variable.

[0007] The ability to easily control or regulate the heating system is further enhanced if the control unit is configured to adjust the amount of outside air supplied so that the dew point temperature of the outside air in the heat pump area is not undercut during heat exchange. This ensures that virtually no condensate forms in the cold spots of a heat pump, thus largely preventing icing.

[0008] The dew point temperature is the temperature below which water condenses from the air.

[0009] The effectiveness of the heating system can be improved if at least one sensor is provided that determines the outside air temperature and / or the outside air humidity.

[0010] The efficiency of the heating system can be improved by including at least one sensor that measures the indoor air temperature and / or humidity. It can also be possible to measure these values ​​of the air in a heat pump housing and use them as the basis for a control strategy.

[0011] Relative humidity is usually measured. This can be used to determine how much water vapor is contained in the air relative to the maximum possible water vapor at a given temperature.

[0012] The effectiveness of the heating system can be improved if at least one sensor is provided that detects icing of the heat exchanger.

[0013] Advantageously, a supply air-exhaust air heat exchanger is provided which tempers and / or dries the outside air to be supplied.

[0014] In a further advantageous manner, it can be provided that the device contains an electric heater and / or a second heat pump.

[0015] The invention also relates to a method for operating a heating system according to the invention, which is characterized by the following steps: • Determine the status of the heat pump, • Determining a temperature and / or a relative humidity of indoor air, • Determining a temperature and / or a relative humidity of outside air, • Supplying a quantity of outside air into an area of ​​the heat pump where icing may occur in such a way that icing is at least largely avoided.

[0016] The status of a heat pump refers to the operating state or operating point of a heat pump at a specific point in time. Indoor air can be understood as both the room air and the air inside the heat pump housing.

[0017] The process can be improved by the following steps: • Empirical and / or mechanical determination of the amount of cold air of a certain humidity that must be supplied to a heat pump in an area where icing may occur in order to prevent icing, • Storing the determined values ​​in a control unit.

[0018] Empirical determination should be understood as meaning that different test series are carried out under laboratory conditions in which different quantities of cool air with a predefined humidity are supplied to the components of the heat pump that are subject to icing at different statuses of a heat pump at different temperatures and air humidity in the environment of the heat pump, with the result "frozen" or "not frozen" being documented.

[0019] Machine learning refers to a type of learning that utilizes previously known, possibly empirically determined, conditions, as well as data sets obtained in real time during field tests or in use, to obtain optimal values ​​for the supplied medium. Neural networks or similar systems are used for this purpose.

[0020] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 a schematic representation of a heating system according to the invention in a house; Fig. 2 a schematic representation of a supply air-exhaust air heat exchanger; Fig. 3 a diagram showing a dew point curve of air, in which the absolute water absorbed in the air in g / m 3 plotted against air temperature; and Fig. 4 a flow chart for a process sequence. Description of embodiments

[0021] Fig. 1 shows a heating system 10 in a room 12 of a house 14. The heating system 10 consists of several components and has, among other things, a collector 16, which in the exemplary embodiment is designed as a PVT collector 18.

[0022] There are various designs of PVT collectors (photovoltaic-thermal solar collectors). In the exemplary embodiment, a PVT air-brine collector 18 is used, which is designed to utilize both solar radiation and thermal energy from the ambient air as a heat source. An air-brine heat exchanger 22 is arranged on the back of a photovoltaic module 20, so that, on the one hand, the photovoltaic module 20 is cooled and, on the other hand, both the waste heat from the photovoltaic module 20 and, by heat extraction from the air, a heat transfer medium 24 flowing through the air-brine heat exchanger is heated. Fig. 1, the heat transfer medium 24 is represented by an arrow, which symbolizes the flow direction of the heat transfer medium 24. Within the PVT collector 18, the heat transfer medium 24 flows in defined, in the Fig. 1 coils not shown.

[0023] A supply line 26 is connected to the air-brine heat exchanger 22, which leads to a heat exchanger 28 of a heat pump 30. A return line 32 then leads from the heat exchanger 28 back to the air-brine heat exchanger 22. This creates a closed heat transfer medium circuit 34. In the exemplary embodiment, a pump 36 is arranged in the supply line 26, which can drive the heat transfer medium 24 during operation. The supply line 26 and the return line 32 preferably run along an exterior side of the house 14 before being led into the room 12.

[0024] The heat pump 30 has a refrigerant circuit 38 in which a refrigerant 40 (symbolized by an arrow) circulates. A compressor 42 and an expansion device 44 are also arranged in the refrigerant circuit 38. In the simplest case, the expansion device 44 is designed as a perforated plate, which generates a back pressure in the refrigerant 40 on an inflow side and leads to an expansion in the refrigerant 40 on the outflow side. This expansion causes the refrigerant 40 to cool, while downstream of the compressor 42, a compression of the refrigerant 40 leads to its heating.

[0025] An additional heat exchanger 46 is arranged in the refrigerant circuit 38. This additional heat exchanger 46 transfers the energy present in the refrigerant circuit 38 to a piping system 48, which is connected to another domestic installation. This domestic installation is not shown, but typically includes heating circuits for heating or cooling rooms and for heating domestic water.

[0026] In the exemplary embodiment, the heat pump 30 with its refrigerant 38 is arranged such that heat is transferred from the heat transfer medium 24 to the refrigerant 40 in the heat exchanger 28. The compressor 42 compresses the refrigerant 40, causing it to heat further. This heat is transferred in the further heat exchanger 46 to heating water circulating in the piping system 48. The refrigerant 40 cools in the process. Following the further heat exchanger 46, the refrigerant encounters the expansion device 44. Due to the expansion, the refrigerant 40 cools significantly and is thus fed to the heat exchanger 28. The refrigerant circuit 38 is thus closed.

[0027] The area 50 from the expansion device 44 to the heat exchanger 28 is therefore the area where the lowest temperatures prevail in the refrigerant 40. In this area 50, there is a risk that condensation from the ambient air will condense on the components of the heat pump 30 and evaporate.

[0028] The invention is based on the finding that systems in which the heat pump 30 is arranged in a room 12 of a house 14 are subject to an increased risk of icing, particularly when low outside temperatures prevail in winter and thus the temperature of the heat transfer medium 24 is also low. Furthermore, a higher temperature and a higher absolute humidity may be present in room 12.

[0029] In conventional solutions, either the refrigerant 40 is not cooled as much to prevent freezing, or separate defrost cycles are run. Both reduce the effectiveness of the heat pump and limit the minimum temperature of the heat transfer medium 24 supplied to the heat pump 30.

[0030] It is now proposed to provide a device 52 that can supply outside air 54 to the heat pump 30, particularly in the area 50. In this way, drifting can be prevented or at least contained. In the exemplary embodiment, the outside air 54 is supplied from outside the house 14. However, it is also possible to obtain the outside air 54, for example, from a garage or a nearby outbuilding. In the exemplary embodiment, the outside air 54 is introduced into a housing 55 surrounding the heat pump 30.

[0031] The heating system 10 has a control unit 56 configured to control or regulate the amount of supplied outside air 54 depending on the current temperature and / or the current humidity of the supplied outside air 54. "Configured" is understood to mean that the control unit 56 has the appropriate hardware with inputs and outputs, logic circuits, memory, and the appropriate software required for such control. The control unit 56 is therefore customized in this respect.

[0032] The control unit 56 is also designed to measure the amount of supplied outside air 54 in such a way that during heat exchange the dew point temperature of the outside air 54 in the area 50 of the heat pump is not undercut.

[0033] The control unit 56 contains a memory that contains, among other things, a digital dew point curve. Fig. Figure 3 shows such a dew point curve for water vapor in air. The absolute humidity of water in grams per cubic meter of air is plotted against the air temperature. It can be seen that lower-temperature air can store relatively less water vapor than higher-temperature air.

[0034] The effect of water condensation on cold surfaces is ultimately based on warm air containing a certain amount of water vapor being cooled by a cold surface to such an extent that the air contains more water vapor than it can absorb at that temperature. This is referred to as falling below the dew point. The water vapor condenses.

[0035] The indoor air 58 present in room 12 now has a temperature and humidity that are present in area 50 of the heat pump 30. A significant cooling of this indoor air 58 in area 50 leads to icing of the cold spots of the heat pump. Device 52 now mixes cool outdoor air 54 with the indoor air 58, so that, on the one hand, the relative humidity decreases and, on the other hand, lower temperatures prevail in the surrounding area 50. To prevent room 12 from cooling too much, control unit 56 measures the amount of outdoor air 54 to be supplied depending on the current temperature and / or the current relative humidity of the outdoor air 54 being supplied.

[0036] For this purpose, the device 52 has a through-opening 60, for example in the form of a window or a core hole, from which a channel 62 guides the outside air 54 toward the area 50. In the exemplary embodiment, a fan 64 is arranged in the channel 62 for this purpose.

[0037] In the embodiment according to Fig. 1, the outside air 54 is introduced into the heat pump housing 55. This creates an air pressure that is higher than that of the surrounding room 12. Warm air inside the room 12 is thus kept away from the cold components of the heat pump 30. The prevailing pressure difference can be used to regulate the supply of outside air 54.

[0038] The outside air 54 is first passed through the warm components, such as the compressor 42, and from there to the cold components, such as the expansion device 44. This additionally tempers and dries the outside air. This has the effect of reducing the temperature level of the refrigerant in the area of ​​the cold components. This also leads to the temperature level of the heat transfer medium 24 in the flow line 26 being reduced. The heat pump 30 can therefore be operated at lower outside temperatures than if the outside air were conveyed directly to the cold components or even if the inside air 58 of the room 12 surrounded the cold components.

[0039] The control unit 56 can either be arranged as a separate component within the heating system 10 or be integrated into a control system of the heat pump 30. In the exemplary embodiment, the control unit 56 is arranged separately and has several connecting lines to components inside and outside the heating system 10.

[0040] The control unit 56 is directly connected to the compressor 42 of the heat pump 30 via a first power line 66. The control unit 56 obtains the necessary electrical energy from the PV module 20 via connecting lines 68. This is an advantage of the PVT collector 18, which, in addition to the necessary heat for the heat exchanger 28 of the heat pump 30, can also provide the necessary electrical energy for the compressor 42. In the event that the energy provided by the PVT collector 18 is insufficient, a separate energy storage device can be provided, or the control unit 56 and / or the individual electrical components of the heating system 10 can be connected to the electrical grid.

[0041] The control unit 56 is connected to an outside sensor 72 via a first sensor line 70. The outside sensor 72 determines the temperature of the outside air 54 and transmits this value to the control unit 56. Depending on the configuration, the outside sensor 72 can determine the air humidity and transmit this value to the control unit 56. In the exemplary embodiment, these values ​​are determined continuously. However, it is also possible to determine and transmit these values ​​discontinuously, i.e., at specific times. In the exemplary embodiment, the control unit 56 is connected to the outside sensor 72 via the sensor line 70. Communication can also be wireless.

[0042] The control unit 56 is connected to an interior sensor 76 via a second sensor line 74. The interior sensor 76 determines the temperature of the interior air 58 and transmits this value to the control unit 56. Depending on the configuration, the interior sensor 76 can determine the air humidity and transmit this value to the control unit 56. In the exemplary embodiment, these values ​​are determined continuously. However, it is also possible to determine and transmit these values ​​discontinuously, i.e., at specific times. In the exemplary embodiment, the control unit 56 is connected to the interior sensor 76 via the sensor line 74. Communication can also be wireless.

[0043] The control unit 56 is connected to a sensor 80 via a third sensor line 78. The sensor 80 monitors the components of the heat pump 30 that are at risk of freezing. In the exemplary embodiment, the sensor 80 is a video sensor that processes the image of these components and can detect freezing, for example, using surface gloss analysis. It then transmits a value to the control unit 56 that indicates the freezing. However, it is also possible for the sensor 80 not to evaluate the recorded data itself, but to transmit it directly to the control unit 56. It is also possible to use a sensor that detects a thermal image instead of a video sensor. Furthermore, it is possible to use one or more sensors that determine electrical capacitance. In the exemplary embodiment, these values ​​are determined continuously.However, it is also possible to determine and transmit these values ​​discontinuously, i.e., at specific times. In the exemplary embodiment, the control unit 56 is connected to the sensor 80 via the third sensor line 78. Communication can also be wireless.

[0044] The control unit 56 is connected to the pump 36 via a first control line 82. Depending on the design of the pump 36, the pump can be switched on or off by the control unit 56, or its output can be continuously varied. The control line 82 can be provided as a simple data transmission line if the pump 36 is connected to a separate power grid. It is also possible for the control unit 56 to provide the energy required to operate the pump 36 via the control line 82 if the control unit 56 receives the corresponding electrical energy via the PV module 20.

[0045] The control unit 56 is connected to the fan 64 via a second control line 84. Depending on the design of the fan 64, the fan can be switched on or off by the control unit 56, or its power can be continuously varied. The control line 84 can be provided as a simple data transmission line if the fan 64 is connected to a separate power supply. It is also possible for the control unit 56 to provide the energy required to operate the fan 64 via the control line 84 if the control unit 56 receives the corresponding electrical energy via the PV module 20.

[0046] The control unit 56 is connected to a device, in this embodiment an auxiliary heater 88, via a second power line 86. The auxiliary heater 88 is available when the heat transfer medium 24 can no longer be heated to the required temperature for the heat pump 30 by the solar collector 16. If the PV module 20 supplies sufficient electrical energy, the auxiliary heater 88 can be supplied with it via the control unit 56. However, the auxiliary heater 88 can also be connected separately to a power supply.

[0047] In the exemplary embodiment, the auxiliary heater 88 is an electric heater arranged around the supply line 26. However, it is also possible to use a separate heat pump that performs the function of the auxiliary heater 88. Furthermore, it is possible to arrange the auxiliary heater 88 in the area of ​​the return line 32. In this way, the solar collector 16 can be protected from excessive overcooling and resulting damage in extreme cases.

[0048] In Fig. Figure 2 shows a detail of a further embodiment of the device 52. It can be seen that the outside air 54 is supplied to the area 50 via the duct 62 and the fan 64. In this embodiment, the air leaving the area 50 is guided back outside via an outlet duct 90. An air-to-air heat exchanger 92 is arranged between the duct 62 and the outlet duct 90. In the air-to-air heat exchanger 92, heat from the air guided from the area 50 or the room 12 is supplied to the outside air 54 supplied from outside. As a result, the outside air 54 is tempered or warmed before it reaches the area 50. This warming also dries the outside air 54 before it reaches the area 50. This, together with the raising of the supply air temperature, also counteracts freezing.

[0049] A method for operating a heating system 10 is characterized by the following steps: • Determine the status of the heat pump 30, • Determining a temperature and / or a relative humidity of indoor air 58, • Determining a temperature and / or a relative humidity of outside air 54, • Supplying a quantity of outside air 54 into an area 50 of the heat pump 30 in which icing can occur, such that icing is at least largely avoided.

[0050] In the exemplary embodiment, the control unit 56 operates the heat pump 30 and is therefore in possession of all necessary data indicating an operating point of the heat pump 30. This includes, for example, temperatures, pressures and / or flow rates in the refrigeration circuit 38 or the performance data of the compressor 42, etc. From this, a status of the heat pump 30 can be determined, which signals a risk of icing of the cold components of the heat pump 30. (Step 100 in Fig. 4)

[0051] In the exemplary embodiment, the control unit 56 is connected to an interior sensor 76, which can determine the temperature of the interior air 58 and / or its humidity. (Step 102 in Fig. 4) This data is fed to the control unit 56. Based on the status of the heat pump 30 in conjunction with the temperature and / or humidity of the indoor air 58 in area 50, the control unit 56 determines the risk of the cold components of the heat pump 30 freezing. The higher the temperature of the indoor air 58 and the higher its relative humidity, the higher the probability that the cold components will freeze.

[0052] In the exemplary embodiment, the control unit 56 is connected to an outside sensor 72, which can determine the temperature of the outside air 54 and / or its humidity. (Step 104 in Fig. 4) This data is fed to the control unit 56. Using the status of the heat pump 30 in conjunction with the values ​​of the indoor air 58 and the calculated probability of the cold components freezing, the control unit 56 determines how much outdoor air 54 should be fed into the area 50 based on its temperature and / or humidity. To do this, the control unit 56 accesses data stored in a memory of the control unit 56. This data reflects empirical values ​​that have led to success in similar situations. (Step 106 in Fig. 4)

[0053] Knowing these values, the control unit 56 acts on the fan 64 so that the specified amount of outside air 54 is directed into the area 50. In this way, icing can be reduced, if not completely prevented. (Step 108 in Fig. 4)

[0054] In a separate method step 110, the data is determined which the control unit 56 accesses while determining the required amount of outside air 54 to be supplied. In the exemplary embodiment, the data is determined empirically in the laboratory. For this purpose, predetermined conditions of the inside air 58 are provided for various predefined set states of the heat pump 30, and then different amounts of outside air 54 of predetermined conditions are supplied. The results are documented and can be stored in a memory. (Arrow 112 in Fig. 4)

[0055] All data can also be simulated using model calculations, or intrapolated or extrapolated based on empirically measured data. These results are also documented and can be stored in a memory.

[0056] If many such data sets already exist, it is possible to obtain and document the results using machine e-learning. This typically involves using a neural network of a heat pump computer. Data sets with various statuses of the heat pump 30, with various indoor air conditions 58 and various amounts of preconditioned outdoor air 54 are input as input data. The result determined by the AI ​​is compared with the true result and subjected to recursion. Once an acceptable degree of true results has been determined, the thus-trained neural network can be implemented in the control unit 56 and used.

[0057] The quality of the trained neural network can be checked or optimized by determining the conditions of the frozen or non-frozen components during operation. (Arrow 114 in Fig. 4)

[0058] Furthermore, the control unit 56 can be remotely monitored or communicate with a cloud. The data used for control can thus be regularly updated. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 102012019525A1

[0002]

Claims

[1] Heating system (10) with at least one collector (16), in particular a PVT collector (18), and with a heat pump (30) installed in a room (12) with a refrigerant circuit (38) in which a refrigerant (40) circulates, and which has at least one heat exchanger (28), at least one compressor (42) and at least one expansion element (44), wherein the heat exchanger (28) of the heat pump (30) is able to exchange heat with the collector (16), in particular the PVT collector (18), characterized by a device (52) capable of supplying outside air (54) to the heat pump (30). [2] Heating system (10) according to one of the preceding claims, characterized by that a control device (56) is provided which is designed to control or regulate the amount of supplied outside air (54) depending on the current temperature and / or the current relative humidity of the supplied outside air (54). [3] Heating system (10) according to one of the preceding claims, characterized by that the control device (56) is designed to measure the amount of supplied outside air (54) in such a way that the dew point temperature of the outside air (54) in the area of ​​the heat pump (30) is not undercut during heat exchange. [4] Heating system (10) according to one of the preceding claims, characterized by that at least one sensor (72) is provided which determines the temperature of the outside air (54) and / or the humidity of the outside air (54). [5] Heating system (10) according to one of the preceding claims, characterized by that at least one sensor (76) is provided which determines the temperature of an internal air (58) and / or the humidity of an internal air (58). [6] Heating system (10) according to one of the preceding claims, characterized by that at least one sensor (80) is provided which detects icing of the heat exchanger (28). [7] Heating system (10) according to one of the preceding claims, characterized by that a supply air-exhaust air heat exchanger (92) is provided which tempers and / or dries the outside air (54) to be supplied. [8] Heating system (10) according to one of the preceding claims, characterized by a device which is capable of raising the temperature of the heat transfer medium (24) which transports heat from at least one solar collector (16), in particular a PVT collector (18), to the heat exchanger (28). [9] Heating system (10) according to claim 8, characterized by that the device (52) contains an electric heater (88) and / or a second heat pump (30). [10] Method for operating a heating system (10) according to one of the preceding claims, characterized by the steps: • Determining the status of the heat pump (30), • Determining a temperature and / or humidity of indoor air, • Determining a temperature and / or humidity of outside air (54), • Supplying a quantity of outside air (54) into an area of ​​the heat pump (30) in which icing may occur, such that icing is at least largely avoided. [11] Method according to claim 10, characterized by following steps: • Empirical and / or mechanical determination of an amount of cold air of a certain humidity that must be supplied to a heat pump (30) in an area where icing may occur in order to prevent icing, • Storing the determined values ​​in a control unit (56).

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