Method for heating at least one building and heating system for at least one building

Abstract

The invention relates to a method for heating at least one building (3) with a geothermal heating system (4) comprising a first ground loop (21) with a first ground storage tank (5) surrounding it and a second ground loop (21A) with a second ground storage tank (5A) surrounding it.by coupling the first ground loop (21) and the second ground loop (21A) via a heat pump (20) in a first operating mode, and by coupling the second ground loop (21A) to a building loop (22) via the heat pump (20) in a second operating mode, and by drawing electricity from a power grid (2), determining the electricity price of the drawn electricity, and if a predetermined price is not exceeded, the geothermal heating system (4) is operated with the drawn electricity in the first or second operating mode, and by feeding heat from the first ground storage (5) into the second ground storage (5A) via the heat pump (20) in the first operating mode, and by feeding heat from the second ground storage (5A) into the building loop (22) via the heat pump (20) in the second operating mode.

Description

[0001] The invention relates to a method for heating at least one building with a geothermal heating system. The invention also relates to a heating system for at least one building with a geothermal heating system.

[0002] Night storage heaters have long been used to heat single-family homes. Night storage heaters convert electricity consumed during periods of low electricity prices into heat and store it in tiled stoves or water tanks for later heating.

[0003] WO 2007 / 109899 A1 discloses an energy supply system with two storage units of a house and a heat pump with which heat can be extracted from the two storage units in order to heat the house.

[0004] DE 10 2014 106 2017 A1 describes a geothermal heating system for heating a number of buildings, in which heat generators are operated using electricity from a public power grid, a heat medium is heated by the heat generator and the absorbed heat is stored in an underground storage facility in order to later heat a house.

[0005] GB 2524551 A describes a heating and cooling system with a heat storage tank and a cold storage tank as well as a heat pump for heating or cooling the house.

[0006] EP 2 573 472 A2 discloses a heating system with a heat pump. The heating system comprises a waste heat circuit and a useful heat circuit, with a heat storage unit arranged in the waste heat circuit and a heat storage unit arranged in the useful heat circuit.

[0007] EP 1 807 672 A0 discloses an energy storage device with a first and a second storage device. The energy storage device is designed to be seasonally operable and to provide the consumer with both heat and cold.

[0008] CH 671622 A5 discloses an air conditioning system for heating in winter and cooling in summer.

[0009] US 8,096,293 B2 discloses a liquid heating system with a solar collector and a geothermal heat exchanger arranged in the ground at a depth of between 0.5 m and 5 m.

[0010] The disadvantage of these systems is that they only insufficiently consume or temporarily store electricity that is provided at low cost in order to later convert it into heat for the building.

[0011] It is therefore an object of the invention to provide a method for heating at least one building which takes into account the different power supplies of power grids.

[0012] In a second aspect, the object of the invention is to provide a heating system for a building which reduces the above-mentioned disadvantage and is suitable for carrying out the method according to the invention.

[0013] The problem is solved in its first aspect by a method having the features of claim 1.

[0014] According to the invention, at least one building is heated using the method, which comprises a geothermal heating system with a first ground loop with a surrounding first ground storage tank and a second ground loop with a surrounding second ground storage tank. The geothermal heating system can be operated in at least two operating modes. In a first operating mode, the first ground loop and the second ground loop are coupled to one another via the heat pump, and in a second operating mode, the second ground loop is coupled to a building loop via the heat pump. Electricity is drawn from a power grid. The power grid can be a public or local private power grid. A value of a current characteristic of the drawn electricity is determined, and if a predetermined value is undershot or exceeded, the heat pump is operated with the drawn electricity in the first or second operating mode.In the first operating mode, heat from the first ground storage tank is fed into the second ground storage tank via the heat pump, and in the second operating mode, heat from the second ground storage tank is fed into the building loop via the heat pump.

[0015] The single geothermal heating system can be used to heat a single building or two buildings or three buildings or any higher number of individual buildings.

[0016] An electricity characteristic is preferably understood as the available amount of electricity, especially a surplus. In connection with this, the value can be understood as an electricity price.

[0017] In the method according to the invention, more than exactly two underground storage units and more than exactly two underground loops from which heat is extracted can also be provided. Three, four, or an even higher number of underground storage units and / or underground loops can also be used.

[0018] A building includes houses but also garages, halls, swimming pools, etc.

[0019] The method according to the invention makes use of the idea of ​​providing a first and a second underground storage facility. A ground storage facility includes sensible heat storage facilities such as earth, sand, topsoil, and aquifers, but also artificially created storage facilities such as concrete cores, i.e., media that noticeably change their heat. Heat can be introduced into the ground storage facility by conducting a warm heat medium through the ground storage facility in an underground loop, i.e., a tube system, and transporting heat from the ground loop into the ground storage facility via a temperature gradient. Conversely, by using a cooler heat medium conducted through the ground loop, heat can be transported away from the ground storage facility via the ground loop. A heat medium can be understood to include various fluids, in particular water enriched with anti-corrosion agents.

[0020] The geothermal heating system can be operated in at least two modes. In the first mode, the heat pump is switched on when a certain value is reached, for example when electricity is cheap, i.e. electricity that is below a predetermined price and is therefore referred to as cheap in this application, and heat is pumped from the first underground storage tank to the second underground storage tank. Cheap electricity here also refers to electricity that generally falls below the predetermined value. This increases the temperature level of the second underground storage tank. The first mode is used when the building does not need to be heated at that moment. For example, if cheap electricity is available during the day due to sunshine or wind, and the building still does not need to be heated because the ambient temperature is sufficiently high, the geothermal heating system can be switched to the first mode.

[0021] In the second operating mode, when electricity is cheap, for example, heat from the second underground storage facility is transported to the building loop, which heats the building. The second operating mode is suitable for use when electricity prices are low, for example, to heat the building immediately. This is the case when the weather is good, the sun is shining and / or the wind is blowing, and cheap electricity is available, but the outside temperature is still so low that the building needs to be heated.

[0022] Independent of these two operating modes, the geothermal heating system can also be operated in other modes, which, however, are not the central subject of the invention. For example, if the second underground storage tank is empty, the geothermal heating system can also be operated by transporting heat from the first underground storage tank via the heat pump into the building loop, or, if electricity is expensive, by transporting heat from the second underground storage tank into the building loop; other operating modes are also conceivable.

[0023] According to the invention, the building's room temperature is measured, and if the temperature falls below a target temperature, the geothermal heating system switches to the second operating mode. If the building's temperature falls below a target temperature, the building must naturally be heated. This is preferably achieved by transporting heat from the second underground storage facility to the building's loop when electricity is cheap.

[0024] In a preferred embodiment of the method according to the invention, the room temperature of the building is measured, and if the target temperature is exceeded, the geothermal heating system is switched to the first operating mode. In particular, in this embodiment of the method according to the invention, the method makes use of the idea of ​​using the available cheap electricity even when the building does not currently need to be heated. This is done by transporting heat from the first to the second underground storage facility using cheap electricity, thereby raising the second underground storage facility to a higher temperature level. Later, if necessary, heat can be transported from the higher-temperature second underground storage facility into the building loop even when electricity is expensive, and the heat pump requires less electricity for this transport than if the temperature of the second underground storage facility had not been raised beforehand.

[0025] Particularly preferably, a plurality of buildings are provided, each with a geothermal heating system, and each of the geothermal heating systems is connected to the electricity grid.

[0026] In principle, operation in other modes is also conceivable. For example, the heated heat medium from the first underground storage tank can also flow through the house loop and then into the second underground loop.

[0027] The problem is solved in its second aspect by a heating system having the features of claim 5.

[0028] The heating system is particularly suitable for carrying out one of the above-mentioned processes, while conversely the above-mentioned processes are also suitable for carrying out with one of the heating systems described below.

[0029] The problem is solved by a heating system for at least one building with a geothermal heating system and a first ground loop with a surrounding first ground storage tank, and a second ground loop with a surrounding second ground storage tank. In a first operating mode, the first ground loop and the second ground loop can be coupled to one another via a heat pump, and in a second operating mode, the second ground loop can be coupled to a building loop via the heat pump. Coupled loops mean that heat is transferred from one loop to the other loop via the heat pump.

[0030] The heat pump has a power connection to a power grid, and a control is provided which determines a value of a power property, in particular an electricity price of the withdrawn power, and if a predetermined electricity price is undershot with the withdrawn power, switches the geothermal heating system into the first or second operating mode, wherein in the first operating mode heat from the first ground storage tank can be fed into the second ground storage tank via the heat pump and in the second operating mode heat from the second ground storage tank can be fed into the building loop via the heat pump.

[0031] The statements made regarding the procedure apply to the heating system accordingly.

[0032] In a preferred embodiment of the heating system according to the invention, first directional valves are arranged in the first ground loop, second directional valves in the second ground loop, and third directional valves in the building loop, and when the electricity price is determined to be below the predetermined electricity price, the control switches the first directional valves such that the first ground loop is connected to a primary side of the heat pump in a heat-medium-conducting manner, and the second directional valves such that the second ground loop is connected to connecting lines between the second ground loop and a secondary side of the heat pump in a heat-medium-conducting manner, and the third directional valves such that the secondary side is connected to the connecting lines in a heat-medium-conducting manner, so that heat can be transported from the first ground storage tank to the second ground storage tank via the heat pump.The preferred further development of the heating system makes use of the idea of ​​operating the heat pump in the first or second operating mode by switching the first, second and third directional valves.

[0033] Particularly preferred is a plurality of buildings, each equipped with a geothermal heating system and connected to the power grid. Advantageously, the heating system can be used for a large number of buildings, for an entire urban area.

[0034] The invention is described using an embodiment in three figures, showing: Fig. 1 a schematic representation of a heating system with four buildings, each with a geothermal heating system and a solar wind farm Fig. 2a Detailed drawing of a heat pump of the geothermal heating system in a first operating mode during heat transport from a first to a second ground storage tank Fig. 2b Heat pump in Fig. 2a in a second operating mode when transporting the heat from the second ground storage into a building loop

[0035] Fig. 1 shows a power generator 1, preferably configured as a wind farm or solar farm, or as a combined wind / solar farm. It may also be a single solar system, a single solar panel, or a single wind turbine. The power generator 1 feeds power into a power grid 2. This may be a public power grid, but it may also be a private power grid that locally supplies power to a building 3 or a number of buildings (3).

[0036] Preferably, each of the buildings 3 has a geothermal heating system 4. Each of the geothermal heating systems 4 comprises a first ground storage tank 5, which is connected to a primary side of a heat pump 20 via a first ground loop 21 in a heat-conducting manner. Each geothermal heating system 4 comprises a second ground storage tank 5A, which is connected to the primary side of the heat pump 20 via a second ground loop 21A and to a secondary side of the heat pump 20 via second directional valves 44A and connecting lines 45. In this exemplary embodiment, the connecting lines 45 are connected to lines of a building loop 22 via third directional valves 41 in a heat-conducting manner.The second ground loop 21A is connected in a heat-conducting manner via the second directional valves 44A either to the connecting lines 45 or to the first ground loop 21, which in turn has first directional valves 44 which, in a first position, enable a connection of the first ground loop 21 to the primary side of the heat pump 20 and, in a second position, enable a connection of the second ground loop 21A to the primary side of the heat pump 20 via the first and second directional valves 44, 44A.

[0037] The geothermal heating system 4 according to the invention can dispense with a separate heat generator.

[0038] A heat medium is preferably understood to be water mixed with additives such as antioxidants.

[0039] A controller 70 is provided, which, on the one hand, determines the electricity price and into which a predefined electricity price can be entered. If the predefined electricity price is undershot, the heat pump 20 is switched to a first operating mode. In the first operating mode, the first directional valves 44 are switched such that the first ground loop 21 is connected to the primary side of the heat pump 20, and the second directional valves 44A and the third directional valves 41 are switched such that the second ground loop is connected to the secondary side of the heat pump 20 via the connecting lines 45. The position of the valves 41, 44, 44A in the first operating mode is Fig. 2a shown. In the first operating mode, the geothermal heating system 4 functions as a heat pump from the first underground storage tank 5 to the second underground storage tank 5A. When electricity is favorable, preferably regardless of the time of day or year, heat is transported from the first underground storage tank 5 to the second underground storage tank 5A with the help of the geothermal heating system 4, thereby raising the second underground storage tank 5A to a higher temperature level.

[0040] The ground storage systems 5, 5A, for example, are sensible heat storage systems such as earth, sand, topsoil, and aquifers, as well as artificially created storage systems such as concrete cores, i.e., media whose heat changes noticeably. The respective ground loops 21, 21A are preferably laid in a serpentine pattern. However, the ground loops 21, 21A can also be designed as a vertical loop extending several tens of meters into the ground or as a geothermal probe. Combinations of horizontally running ground loops and vertically running loops are also conceivable.

[0041] The Fig. 2a and 2bThe heat pump 20 shown conventionally has a heat exchanger circuit in which a heat exchange medium circulates. The heat exchanger circuit is separated from the first and second ground loops 21, 21A and the building loop 22, in the sense that no exchange of heat media takes place between the heat exchanger circuit and any of the three loops 21, 21A, 22. The heat pump 20 comprises an evaporator 27. The heat exchange medium enters the evaporator 27 in a liquid state, is evaporated there, and absorbs heat from the heat medium of the first or second ground loop 21, 21A through evaporation. The temperatures are set such that the temperature of the heat exchange medium in the flow direction upstream of the evaporator 27 is below the temperature of the heat medium of the connected ground loops 21, 21A in the flow direction upstream of the inlet to the evaporator 27.During its circulation, the evaporated heat exchange medium enters a compressor 28, where it is compressed, further increasing the temperature of the gaseous heat exchange medium. The gaseous heat exchange medium then enters a condenser 29 on the secondary side of the heat pump 20. In the condenser 29, the heat exchange medium transfers heat to the heat medium of the building loop 22. The temperatures in the condenser 29 are adjusted so that the temperature of the gaseous heat exchange medium before entering the condenser 29 is higher than the temperature of the heat medium of the building loop 22 before it enters the condenser 29. Due to the temperature gradient, a heat flow occurs from the heat exchange medium into the heat medium of the building loop 22. Due to the heat transfer, the heat exchange medium liquefies and enters a throttle 30 in a liquid state.In the throttle 30, the liquid heat exchange medium is expanded, whereby the temperature is further reduced, and the low-temperature heat exchange medium reaches the beginning of the circuit to the evaporator 27.

[0042] In the present embodiment, the compressor 28 also includes a heat generator 23. However, the heat generator 23 is not absolutely necessary. The gaseous heat exchange medium can thus be additionally heated by adding heat, for example, when electricity is cheap.

[0043] In the first and in Fig. 2a In the operating mode shown, heat is transported from the first ground storage tank 5 via the first ground loop 21 into the heat pump 20. For this purpose, the first directional valves 44 connect the first ground loop 21 to the primary inlet of the heat pump 20 in a heat-medium-conducting manner. The heat is released via the heat pump 20 via the secondary side of the heat pump 20 to the building loop 22. However, the heat is not transported along the building loop 22; rather, after a short section, the third directional valves 41 are switched such that the heat released via the secondary side is transported via the connecting lines 45 and the second correspondingly switched directional valves 44A to the second ground loop 21A, and from there the heat is stored in the second ground storage tank 5A.The release of heat from and into the ground storage 5, 5A occurs preferably through temperature difference, which creates a heat flow due to the temperature gradient.

[0044] To move the heat medium, a first primary pump 24 is provided in the first ground loop 21, a second primary pump 24A is provided in the second ground loop 21A and a secondary pump 25 is provided in the building loop 22.

[0045] In the first operating mode, the building is therefore not yet heated, but rather the heat is transported from the first to the second underground storage unit 5, 5A, so that the second underground storage unit 5A is brought to a higher temperature level, wherein the temperature level of the second underground storage unit 5A was preferably already higher than the temperature of the first underground storage unit 5 before the transport.

[0046] In the Fig. 2b The second operating mode of the heat pump 20 of the geothermal heating system 4 is shown. In the second operating mode, the building 3 is heated. For this purpose, the first ground loop 21 is taken from the heat pump 20 via the corresponding position of the first directional valves 44, while Fig. 2b shows how the second ground loop 21A is connected to the primary side of the heat pump 20 via the corresponding position of the first and second directional valves 44, 44A. Regardless of the electricity price, preferably when electricity is cheap, heat is extracted from the second ground storage tank 5A and transferred to the building loop 22 via the heat pump 20. An electricity meter 71 counts the electricity consumed. For this purpose, the third directional valves 41 are switched over and connect the secondary side to the building loop 22 and disconnect the connecting lines 45 from the secondary side. Extracting heat from the second ground storage tank 5A has the advantage that the temperature level of the second ground storage tank has been increased during the first operating mode, so that significantly less electricity is required to generate the same temperature level in building 3 than if the heat had been extracted from the first ground storage tank 5.However, the geothermal heating system 4 is flexible for transporting the heat from the first underground storage tank 5 to the second underground storage tank 5A: it can carry out this pumping at any time of day using cheap electricity and then use the higher temperature level of the second underground storage tank 5A while heating the building 3.

[0047] The heating system can also operate in other modes. If, for example, inexpensive electricity is not available for an extended period, no heat is supplied to the second underground storage tank 5A for an extended period. This can cause the temperature of the second underground storage tank 5A to drop. It can also drop below the temperature of the first underground storage tank 5. Since the building 3 still needs to be heated, the available expensive electricity is used to pump heat from both underground storage tanks 5, 5A simultaneously to the primary side of the heat pump 20 and transport it via the heat pump 20 into the building loop 22. For this purpose, the second directional valves 44A are connected to establish a connection between the second underground loop 21A and the primary side of the heat pump 20. According to Fig. 2a the second directional valves 44A are open to the first directional valves 44. The first directional valves 44 can also be fully opened, so that a heat medium-conducting connection is established between the first ground loop 21 and the primary side of the heat pump 20, as well as simultaneously a heat medium-conducting connection between the second ground loop 21A via the second directional valves 44A and the first directional valves 44 to the primary side of the heat pump 20. Bezugszeichenliste

[0048] 1Central power generator 2Power grid 3Building 4Geothermal heating system 5First underground storage 5Second underground storage 20Heat pump 21First ground loop 21ASecond ground loop 22Building loop 23Heat generator 24First primary pump 24ASecond primary pump 25Secondary pump 27Evaporator 28Compressor 29Condenser 30Throttle 40Secondary connecting lines 41Third directional valves 42Directional valve 43Primary connecting lines 44First directional valves 44Second directional valves 45Connecting lines 70Control 71Electricity meter

Claims

1. Method for heating at least one building (3) with a geothermal heating system (4) with a first ground loop (21) with a first ground storage tank (5) surrounding it and a second ground loop (21A) with a second ground storage tank (5A) surrounding it, in that, in a first operating mode, the first ground loop (21) and the second ground loop (21A) are coupled to one another via a heat pump (20) and, in a second operating mode, the second ground loop (21A) is coupled to a building loop (22) via the heat pump (20) and current is drawn from a power supply system (2) and a value of a current characteristic of the extracted current is determined and, if the extracted current falls below a predetermined value, the geothermal heating system (4) is operated in the first or second operating mode and in the first operating mode heat is fed from the first ground storage tank (5) via the heat pump (20) into the second ground storage tank (5A) and in the second operating mode heat is fed from the second ground storage tank (5A) via the heat pump (20) into the building loop (22), characterised in that a room temperature of the building (3) is measured and the geothermal heating system (4) is switched to the second operating mode when the temperature falls below a setpoint temperature.

2. Method according to claim 1, characterised in that a room temperature of the building (3) is measured and the geothermal heating system (4) is switched to the first operating mode when the setpoint temperature is exceeded.

3. Method according to one of claims 1 to 2, characterised in that a plurality of buildings (3) are each provided with a geothermal heating system (4) and each of the geothermal heating systems (4) is connected to the power grid.

4. Heating system for at least one building (3) with a building loop (22), with a heat pump (20) and with a geothermal heating system (4) with a first ground loop (21) with a first ground storage tank (5) surrounding it and a second ground loop (21A) with a second ground storage tank (5A) surrounding it, wherein, in a first operating mode, the first ground loop (21) and the second ground loop (21A) can be coupled to one another via a heat pump (20) and, in a second operating mode, the second ground loop (21A) can be coupled to a building loop (22) via the heat pump (20) and the heat pump (20) has a power connection to a power supply system (2), and a controller (70) is provided, which determines a value of a current characteristic of the current drawn and switches the geothermal heating system (4) into the first or second operating mode when the current falls below a predetermined value and, in the first operating mode, heat can be fed from the first ground storage tank (5) via the heat pump (20) into the second ground storage tank (5A) and, in the second operating mode, heat can be fed from the second ground storage tank (5A) via the heat pump (20) into the building loop (22), characterised in that the controller (70) measures a room temperature of the building (3) and switches the geothermal heating system (4) to the second operating mode when the temperature falls below a setpoint temperature.

5. Heating system according to claim 4, characterised in that first directional valves (44) are arranged in the first ground loop (21), second directional valves (44A) are arranged in the second ground loop (21A) and third directional valves (41) are arranged in the building loop (22) and the controller (70) switches the first directional valves (44) when a current price below a predetermined current price is detected, such that the first ground loop (21) is connected to a primary side of the heat pump (20) so as to conduct heat medium and switches the second directional valves (44A) in such a way that the second ground loop (21A) is connected to connecting lines (45) between the second ground loop (21A) and a secondary side of the heat pump (20) so as to conduct heat medium, and switches the third directional valves (41) so that the secondary side is connected to the connecting lines (45) so as to conduct heat medium, so that heat can be transported from the first ground storage tank (5) into the second ground storage tank (5A) via the heat pump (20).

6. Heating system according to one of claims 4 or 5, characterised in that a plurality of buildings (3) is provided, each of which has a geothermal heating system (4) and is connected to the power grid.

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