DE102022110560A1 - Heat pump - Google Patents

Abstract

The invention relates to a heat pump, having a gas as a refrigerant, a first countercurrent heat exchanger, a compressor, a first heat exchanger, a second countercurrent heat exchanger, at least one generator, and a second heat exchanger.

Description

The invention relates to a heat pump.

This is a device that absorbs thermal energy from the environment. Through the use of technical work, this is transferred as useful heat to a system to be warmed.

Heat pumps usually use a refrigerant that is liquid at room temperature. However, the physical state changes between liquid and gaseous, meaning that the pressure energy that occurs in the above process cannot be recovered.

It is therefore an object of the invention to create a heat pump and a method for operating a heat pump which has high efficiency.

This task is solved through the subject matter and the method of the independent claims.

According to the invention, the heat pump has a gas, preferably air, for example ambient air, as a refrigerant. The refrigerant is therefore gaseous at room temperature. For example, the heat pump can also be referred to as a compressed air heat pump. This functionality is possible due to the internal thermal energy.

The heat pump has a first countercurrent heat exchanger. Preferably the gas is heated therein.

The first countercurrent heat exchanger can, for example, have an efficiency of at least 90%.

The heat pump has a compressor. The compressor can also be called a compressor. This serves to compress the gas.

When compressed, the gas heats up due to friction losses from the compressor and due to thermal energy, i.e. the internal thermal energy of the gas. Since the gas has less volume available after compression than before, it heats up significantly.

This leads to an additional increase in pressure due to thermal expansion.

When the gas, e.g. compressed air, cools down to ambient level, this energy is usually lost. In addition, the pressure also drops here as the gas contracts again as it cools down.

The heat pump has a first heat exchanger, e.g. water heat exchanger.

The heat dissipated by the first heat exchanger can be used, for example, for heating.

After the first heat exchanger, the gas may still have a certain amount of heat. The gas is therefore preferably fed into the first countercurrent heat exchanger. The heat can be used to warm the incoming gas, which is led to the compressor.

The first countercurrent heat exchanger, the compressor and/or the first heat exchanger can be designed as separate components. Alternatively, at least two of these components can be designed as a unit.

The first countercurrent heat exchanger can be arranged with the compressor, preferably at the inlet of the compressor, and/or the first heat exchanger, preferably at the outlet of the first heat exchanger.

For example, the compressor can be thermally coupled to the first heat exchanger.

The heat pump has a second countercurrent heat exchanger.

The second countercurrent heat exchanger can, for example, have an efficiency of at least 90%.

The gas cools down further in the second countercurrent heat exchanger.

The heat pump has at least one generator. The generator can preferably be a turbine, an expander and/or a throttle.

This means that the energy generated in the compressor can be recovered as effectively as possible in the form of pressure.

As the gas in the generator expands, the temperature continues to decrease. In this way, the gas cools down to a temperature level below its initial state.

The heat pump has a second heat exchanger, e.g. water heat exchanger.

The gas expanded in the generator strives to absorb thermal energy in the second heat exchanger. The second heat exchanger can therefore be used for cooling.

After the second heat exchanger, the gas is still comparatively cold. The gas is therefore preferably fed into the second countercurrent heat exchanger. The cold can be used to cool the incoming gas, which is led to the generator.

The gas flowing in to the compressor or generator can be preheated or precooled with the gas flowing out of the heat exchangers.

This means that a large proportion of energy is recovered.

The temperature is preferably regulated via the flow rate of the first and second heat exchangers or by cyclically switching the compressor on and/or off.

The second countercurrent heat exchanger, the generator and/or the second heat exchanger can be designed as separate components. Alternatively, at least two of these components can be designed as a unit.

The second countercurrent heat exchanger can be arranged with the generator, preferably at the inlet of the generator, and/or the second heat exchanger, preferably at the outlet of the second heat exchanger.

For example, the generator can be thermally coupled to the second heat exchanger.

Since a lot of energy is recovered by the two counterflow heat exchangers and the generator, the heat pump is highly efficient overall.

Further developments of the invention can also be found in the dependent claims, the description and the accompanying drawings.

According to one embodiment, the compressor and the first heat exchanger are connected to one another in such a way that the gas is compressed isothermally.

Preferably, the countercurrent heat exchangers, in conjunction with good thermal coupling, can lead to an approximately isothermal compression or expansion. Temperature changes are dissipated directly after they occur in the heat exchangers or are transferred to the incoming gas through the countercurrent heat exchangers.

Pressure changes during the exchange of heat energy preferably occur little or not at all, since the pressure is compensated for by the volume.

When a gas is heated or cooled, it expands or contracts.

A pressure change would occur in a sealed container. It is therefore advantageous to connect the compressor and the first heat exchanger to one another, so that there is a quasi-open system.

The pressure conditions of the entire system are not significantly influenced. The air that flows to the compressor, for example, absorbs heat and wants to expand.

Since this is not a closed system and the flow resistance is correspondingly low, this leads to the most uniform increase in volume or decrease in flow velocity through the countercurrent heat exchanger.

In order to achieve isothermal compression or expansion, it is necessary to dissipate the resulting heat or cold as quickly as possible so that it cannot influence the pressure or compression.

To achieve this, multi-stage compressors can be used, for example. Alternatively, very slow compression would be possible, but this would require a lot of time to communicate with the environment.

Alternatively, the compressor and the first heat exchanger can be arranged in a common housing.

Furthermore, a section of the first countercurrent heat exchanger facing the compressor or the first heat exchanger can be arranged in the housing.

Conditions in the housing can preferably be like those in a heat bath.

At least one actuator can preferably be provided in the housing.

For example, a medium, preferably a gas, such as air, can circulate in this housing. The gas can be circulated, for example, by a forced fan of the actuator.

The forced fan can be, for example, the ventilation wheel in a conventional electric motor, which rotates with the motor shaft because it sits on it and thus cools the motor or circulates the air around the motor.

As an alternative to gas, other media such as oil are also conceivable. These media can be advantageous, for example, due to the specific heat capacity in conjunction with the thermal conductivity and/or the circulation speed.

If, for example, an increase in temperature occurs during compression, this will be transferred to the medium in the housing as quickly as possible. This in turn releases the energy to the first heat exchanger and/or a section of the first countercurrent heat exchanger facing the compressor or the first heat exchanger.

This means, for example, that unnecessary heating of the compressor or the gas to be compressed can be prevented as much as possible. Smaller differences of a few Kelvin are still present, because without temperature differences there would no longer be any thermal energy flows.

According to a further embodiment, the generator and the second heat exchanger are connected to one another in such a way that the gas is expanded isothermally.

In this regard, reference is made to the above statements in connection with the compressor and the first heat exchanger. These statements can be transferred accordingly to the generator, the second heat exchanger and the second countercurrent heat exchanger.

For example, the generator and the second heat exchanger can be arranged in a common housing.

Furthermore, a section of the second countercurrent heat exchanger facing the generator or the second heat exchanger can be arranged in the housing.

Conditions in the housing can preferably be like those in a heat bath.

The compressed, internal thermal energy of the pressurized gas can preferably be dissipated as isothermally as possible in the form of heat.

According to a further embodiment, the heat pump has a refrigeration dryer.

The refrigeration dryer can preferably be arranged between the outlet of the first countercurrent heat exchanger and the inlet of the second countercurrent heat exchanger.

The refrigeration dryer is preferably used to separate moisture, e.g. air humidity, above the pressure dew point so that the moisture does not freeze in the area of the second heat exchanger and thus lead to blockages or poor heat transfer.

According to a further embodiment, at least two generators are provided.

These can be used to relax the compressed air.

For example, the generators can generate a gap. In this space, the gas pressure can be kept between approximately 6 to 8 bar absolute (total compression approximately 10 to 16 bar).

According to a further embodiment, a valve is provided between the two generators.

For example, part of the gas pressure can be directed via the valve into a separate, thermally insulated container. Preferably, gas can be diverted in such a way that a temperature of approximately -50 to -55 ° C can be established.

With a compression of 7 bar, temperatures of 258°C are possible, i.e. a difference of approx. 238°C to 20°C.

Since pressurized air at 20°C also absorbs approximately the energy that it has already given off in the area of the first heat exchanger, and this, when relaxed, results in the corresponding cooling, a 75 K temperature difference represents -55°C of 20 °C is not a problem.

This roughly corresponds to the vapor pressure at which CO2 changes from its gaseous state to the liquid state.

According to a further embodiment, the heat pump has a CO2 separator.

Since the moisture in the gas can be separated using a refrigeration dryer, for example, and carbon dioxide is the gas in our atmosphere that has the lowest vapor pressure, the purest possible separation of the carbon dioxide contained in the gas is possible.

Liquefaction may generate some heat due to the heat of condensation (heat of vaporization), which inhibits the cooling process. However, since the volume share of CO2 is only 0.04%, this share can be ignored. Otherwise, additional heat exchangers and/or cooling could be provided for the separator. For example, a CO2 refrigeration dryer could be built.

Overall, the heat pump according to the invention can be used to heat and/or cool more efficiently than with conventional heat pumps. It is optionally possible to separate both water in the form of the moisture in the gas and/or CO2 in a cost-effective and liquid manner.

It is also possible to divert part of the gas pressure after the refrigeration dryer and use it for compressed air applications.

Preferably, the heat pump can have a compressed air storage.

Power peaks often occur, especially with renewable energies such as sun or wind, for example when there is strong sunlight or there is a lot of wind. Conversely, it also happens that there are so-called lulls in which there is neither solar energy in the form of light nor wind.

Therefore at least one compressed air storage can make sense. Compressed air storage systems are becoming more and more important compared to batteries because they are simple, robust, long-lasting and cost-effective and do not use rare raw materials or lose capacity.

In this way, the heat pump can replace not only any conventional heat pump but also any compressed air compressor. As long as heat is needed, this system runs as a heat pump. If compressed air is needed, the generator becomes less important and the heat pump runs as a compressed air compressor with heat recovery.

The recovery of pressure energy is difficult or impossible with conventional heat pumps due to the change in the physical state of the refrigerant from liquid to gaseous or vice versa and the associated volume changes (factor 800 to 1200). These disadvantages are eliminated by the heat pump according to the invention.

According to a further embodiment, the heat pump, preferably the first and/or second heat exchanger, has at least one Peltier element.

Two Peltier elements are preferably provided. For example, a Peltier element can be arranged on the first heat exchanger and another Peltier element on the second heat exchanger.

In principle, exactly as much heat energy should be given off in the area of the first heat exchanger as is absorbed in the area of the second heat exchanger.

However, since not exactly as much heat as cold is usually required, this can lead to overheating in the area of the first heat exchanger or to undercooling in the area of the second heat exchanger, which is mainly caused by the countercurrent heat exchangers that are intended to equalize the temperatures.

For example, heat sinks with fans, e.g. fans that can release excess heat or cold to the environment, can be provided to keep the process in balance.

This energy consumption or energy consumption can preferably be regulated via the speed of the fans. These can be arranged in an air duct, e.g. a pipe, which leads to a build-up of heat or cold when the fans are switched off.

Due to the air duct or heat accumulation, little or no heat or cold is wasted when the fans are switched off.

The air in the pipe can serve as an insulator from the environment. If heat or cold is to be dissipated, the fans generate artificial convection, whereby the air used for insulation is used to release or absorb excess energy.

This can preferably be reinforced by, for example, electrical and/or mechanical flaps. The flaps can preferably be arranged at the ends of the tube. Electric flaps can be controlled, for example. Mechanical flaps can also open or close automatically based on convection and/or flow direction.

In order to utilize the energy flows, Peltier elements can be provided between the heat exchangers and the heat sinks.

These are, so to speak, purely electric heat pumps that can also be used in reverse. Not only to pump heat energy from the cold side to the warm side, but also to be able to use an existing temperature difference to generate electrical energy.

The invention further relates to a method for operating a heat pump according to the invention, in which the gas is heated in the first countercurrent heat exchanger.

The gas is then compressed in the compressor.

The gas then gives off heat in the first heat exchanger.

The gas also gives off heat in the first countercurrent heat exchanger.

In this way, the incoming or sucked gas can be preheated in the first countercurrent heat exchanger.

The gas is now cooled in the second countercurrent heat exchanger.

The gas in the generator is then expanded.

The gas then absorbs heat in the second heat exchanger.

Finally, the gas absorbs heat in the second countercurrent heat exchanger.

In this way, the incoming gas can be pre-cooled in the second countercurrent heat exchanger.

According to one embodiment, moisture of the gas and/or CO2 is separated.

All embodiments and components of the device described here are preferably designed to be operated according to the method described here, for example by means of a control device. Furthermore, all embodiments of the device described here and all embodiments of the method described here can each be combined with one another, preferably also independently of the specific embodiment in the context of which they are mentioned.

• 1 eine schematische Darstellung einer Ausführungsform einer erfindungsgemäßen Wärmepumpe,
• 2 eine schematische Darstellung einer weiteren Ausführungsform einer erfindungsgemäßen Wärmepumpe, und
• 3 eine schematische Darstellung einer Schutzvorrichtung einer Ausführungsform einer erfindungsgemäßen Wärmepumpe.

The invention is described below by way of example with reference to the drawings. Show it:

• 1 a schematic representation of an embodiment of a heat pump according to the invention,
• 2 a schematic representation of a further embodiment of a heat pump according to the invention, and
• 3 a schematic representation of a protective device of an embodiment of a heat pump according to the invention.

First of all, it should be noted that the embodiments shown are purely exemplary in nature. Individual features can be implemented not only in the combination shown, but also alone or in other technically sensible combinations. For example, the features of one embodiment can be combined in any way with features of another embodiment. For example, the in 3 The protective device shown is optional for the in 1 and or 2 The heat pump shown can be used.

If a figure contains a reference symbol that is not explained in the directly associated description text, reference is made to the corresponding previous or subsequent statements in the figure description. The same reference numbers are used for the same or comparable components in the figures and these are not explained again.

1 shows a heat pump with a first countercurrent heat exchanger 10, a compressor 12 and a first heat exchanger 14.

Optionally, the compressor 12, the first heat exchanger 14 and a section of the first countercurrent heat exchanger 10 facing the compressor 12 or the first heat exchanger 14 can be arranged in a first housing 16.

Conditions in the housing 16 can preferably be those of a heat bath.

The heat pump has a second countercurrent heat exchanger 20, at least one generator 22 and a second heat exchanger 24.

Optionally, the generator 22, the second heat exchanger 24 and a section of the second countercurrent heat exchanger 20 facing the generator 22 or the second heat exchanger 24 can be arranged in a second housing 26.

Conditions in the housing 26 can preferably be those of a heat bath.

A gas 28, for example ambient air, is heated in the first countercurrent heat exchanger 10, compressed in the compressor 12, and gives off heat in the first heat exchanger 14 and in the first countercurrent heat exchanger 10.

The gas 28 is cooled in the second countercurrent heat exchanger 20, expanded in the generator 22 and absorbs heat in the second heat exchanger 24 and in the second countercurrent heat exchanger 20 and finally exits as exhaust air 30.

In 2 A heat pump is shown, which is compared to the illustration in 1 has numerous optional components. These components can be added individually or in combination to the heat pump. For example, it is possible that the heat pump has a refrigeration dryer 32 but no compressed air storage 34 and vice versa. Accordingly, the heat pump can have both a refrigeration dryer 32 and a compressed air storage 34.

Moisture 36 can be removed from the gas 28 via the refrigeration dryer 32.

The compressed air storage 34 can store compressed air 38, which can be used for various applications.

Two generators 22 can optionally be provided. A valve 40 can optionally be arranged between the generators.

The valve 40 can optionally be connected to a CO2 separator 42, via which liquid CO2 44 can be separated.

Part of the unused energy can be recovered via Peltier elements 46.

3 shows a protective device to prevent overheating on the first heat exchanger 14 or undercooling on the second heat exchanger 24.

Fans 50 and a heat sink 52 are provided in a tube 48.

The heat sink 52 is in contact with the Peltier element 46.

Together with the fans 50, the heat sink 52 ensures that excess heat or cold is released into the environment in order to keep the process in balance.

Reference symbol list

10

first countercurrent heat exchanger

12

compressor

14

first heat exchanger

16

first housing

20

second countercurrent heat exchanger

22

generator

24

second heat exchanger

26

second housing

28

gas

30

Exhaust air

32

Refrigeration dryer

34

Compressed air storage

36

humidity

38

Compressed air

40

Valve

42

CO2 separator

44

CO2

46

Peltier element

48

Pipe

50

Fan

52

Heat sink

Claims (10)

Heat pump, comprising a gas (28) as a refrigerant, a first countercurrent heat exchanger (10), a compressor (12), a first heat exchanger (14), a second countercurrent heat exchanger (20), at least one generator (22), and a second heat exchanger (24). Heat pump after Claim 1 , characterized in that the compressor (12) and the first heat exchanger (14) are connected to one another in such a way that the gas (28) is compressed isothermally. Heat pump after Claim 1 or 2 , characterized in that the generator (22) and the second heat exchanger (24) are connected to one another in such a way that the gas (28) is expanded isothermally. Heat pump according to one of the preceding claims, characterized in that the heat pump has a refrigeration dryer (32). Heat pump according to one of the preceding claims, characterized in that at least two generators (22) are provided. Heat pump after Claim 5 , characterized in that a valve is provided between the two generators (22). Heat pump according to one of the preceding claims, characterized in that the heat pump has a CO2 separator (42). Heat pump according to one of the preceding claims, characterized in that the heat pump, preferably the first and/or second heat exchanger (14, 24), has at least one Peltier element (46). Method for operating a heat pump according to one of the preceding claims, in which the gas (28) is heated in the first countercurrent heat exchanger (10), is compressed in the compressor (12), and gives off heat in the first heat exchanger (14) and in the first countercurrent heat exchanger (10). , the gas (28) is cooled in the second countercurrent heat exchanger (20), is expanded in the generator (22) and absorbs heat in the second heat exchanger (24) and in the second countercurrent heat exchanger (20). Procedure according to Claim 9 , characterized in that moisture (36) of the gas (28) and / or CO2 (44) is separated.

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