EP2199706B1 - A switching device air conditioner and operation method thereof - Google Patents

Description

The invention relates to a cabinet air conditioner with a compressor, a condenser, an expansion valve, a heat receiving means, and a refrigerant circuit for performing a compression operation in which a refrigerant is compressed via the compressor to high pressure level and passed into the condenser and cooled there, wherein Heat energy is released to an environment and is then expanded through the expansion valve, wherein the refrigerant evaporates by absorbing heat through the heat receiving means. Furthermore, the invention relates to a method for operating a cabinet air conditioner for cooling a cabinet, wherein in a compression operation of the cabinet air conditioner (19) in a refrigerant circuit of the cabinet air conditioner (19) a refrigerant via a compressor (11) is compressed to high pressure level and in a condenser (12) and is cooled there, wherein heat energy is released to an environment, and then via an expansion valve (13) is relaxed, so that the refrigerant evaporates by absorbing heat energy through a heat receiving means (14)

For heat dissipation in cabinets, it is known to use air conditioners of the type mentioned. In this climate operation, cooling takes place almost independently of the ambient temperature, so that cooling also takes place when the ambient temperature is higher than the desired control cabinet temperature.

Due to the heat emission to the environment according to this principle, however, high energy consumption is caused by the relatively high energy required for the compression process of the refrigerant.

In the JP 60057154 a solar heat pump is described, which is suitable for buildings and represents a combination of cooling system and solar heating.

The US 2008/0115515 describes a so-called hybrid solution with a cooling mode and a pumping operation for building cooling.

In the WO 2008/079116 a cooling system is described, which combines the pumping operation with a cooling mode according to the compression-expansion principle.

By the DE 100 13 039 A1 a refrigeration device for a cabinet with a refrigeration cycle is known, which has a compressor, an evaporator and a condenser.

In the WO 2008/082379 A1 An air conditioner is described, which is based on the compression principle and additionally has a mode in which the coolant is circulated by means of a pump.

The invention has for its object to provide a cabinet air conditioner for cabinets of the type mentioned, which consumes less total electrical energy, d. H. with a very low energy consumption.

This object is achieved by a cabinet air conditioner according to claim 1. In this case, an alternative pumping operation takes place, in which the refrigerant is circulated without pressure change, so that a heat transfer takes place according to a heat exchanger principle.

The invention is based on the idea that at a lower ambient temperature and higher cabinet temperature heat exchange takes place by pumping the refrigerant. The heat output absorbed in the control cabinet is transferred to the fluid in the internal heat exchanger, heats the fluid and is delivered to the outer heat exchanger. Here, the absorbed heat output is delivered to the cooler ambient air. Heat-emitting control cabinet components may be electronic components such as programmable logic controllers, other controllers, computers, servers, telecommunications equipment and the like, as well as electromechanical components such as switchgear. In general, cabinets are often housed in special rooms for switchgear or in other rooms in which an ambient temperature of about 20 ° occurs relatively often. At this temperature, a heat exchange according to the principle of a heat exchanger is low. In pumping mode, preferably no compressor is used. A high pressure is not required in pumping operation. High pressure is required to provide the high pressure. Electrical energy is only needed to run the required pump or additional fans. However, this energy requirement is relatively low.

A further reduction of components is realized in a simple manner by providing heat exchangers designed for both plants both in the compression mode and in the pumping mode.

A significant advantage of the invention is that cabinets can be designed with very high IP protection class, because the pumping operation according to the heat exchanger principle allows a closed cabinet system without direct air inlet openings, as it is for air conditioning with e.g. Filter fans would be necessary.

Another advantage of the air conditioner according to the invention is that components such as condenser or heat exchanger can be used for both modes, whereby the number of additional components required is relatively low.

The circulating refrigerant fluid practically fulfills various functions.

A first function is the use as a conventional refrigerant in a compression refrigeration cycle with the thermodynamic processes of compressing and expanding, evaporating and liquefying. By compressing from a low pressure to a high pressure, the refrigerant is able to absorb heat at low evaporation temperature and thereafter discharge to the environment at high pressure and temperature in the condenser. During the subsequent expansion of the refrigerant via the expansion valve, the high pressure is brought to low pressure. The refrigerant expands, evaporates and withdraws heat from the control cabinet.

A second function of the fluid is that of pure thermal energy transport in pumping mode, without pressure change. The fluid absorbs the heat loss generated by the cabinet components in the heat exchanger and transports it to the outside. Evaporation and condensation processes do not necessarily take place here, but can be part of the heat exchange.

Surprisingly, the same coolant can be used in a cabinet cooling for both types of cooling, so that the cooling process can be carried out substantially or over large parts of the circle via a common circuit.

The invention is based on the fact that a combination of a standard refrigeration cycle in the air-conditioning mode with a pumping operation without pressure change of a fluid provides efficient cooling with a lower energy requirement. The invention is thus based on an extension of a standard refrigeration cycle.

An inexpensive solution for pumping the fluid is provided by the fact that a pump is connected in parallel to the expansion valve, through which the refrigerant is pumped during pumping operation. Due to the parallel connection

a branch, in which the expansion valve can be closed in pumping operation, so that the fluid can flow only through the pump.

Furthermore, it is provided in the air conditioner that a bypass line is connected in parallel to the compressor, through which the refrigerant is pumped during pumping operation. Through the bypass line, a fluid can be transported without flowing through the compressor and without pressure difference during pumping operation. The bypass line can be closed, for example via a shut-off valve.

Further, in the pumping mode, the refrigerant is pumped via the condenser. The condenser then fulfills two functions. The first function is the liquefaction of the gaseous refrigerant by the heat transfer to the environment. The other function is heat dissipation for pumping.

Further advantageous embodiments of the invention are characterized in the subclaims.

It is particularly advantageous if after the condenser a collecting container for the liquid refrigerant is connected. As a result, on the one hand, the cooling system without the use of the pump work analogously to a gravity heating, which reduces the energy consumption and creates a structure with few components. On the other hand, the reservoir acts as a buffer, so that a trouble-free operation is given when switching from one mode to another. Conveniently, the sump is disposed between the branch to the pump and the expansion valve and the condenser.

A common use of condenser and evaporator is possible when pumped the refrigerant via condenser and evaporator without pressure change, so that takes place through the condenser, heat dissipation to the environment or in the evaporator, the heat absorption. As a result, a cost-effective implementation of the invention is possible.

Conveniently, the various operating modes can be selectively operated by switching over from the compression mode to pumping mode and vice versa via shut-off valves.

A control can be done in the simplest way by a two- or three-point control. For example, there may be three temperature windows. The first temperature window with a low temperature range defines that neither climatic operation nor pumping occurs. No cooling is required here. The second temperature window with a medium temperature range defines that only one pumping operation takes place. The third temperature window with a higher temperature range defines that only one climatic operation takes place.

Instead of multipoint control, dynamic control structures such as P, I, IP, PID controllers and the like can also be used.

In addition or as an alternative to the regulation dependent on the internal temperature, the control device can be effected by a pump operation which is temperature-dependent with respect to an ambient temperature. It is therefore possible that the ambient temperature is present as a parameter in the control loop. This is done by an ambient temperature sensor connected to the control device reached. The consideration of the ambient temperature brings in a simple way the desired energy savings. By taking into account the ambient temperature in the control as a parameter, namely at a relatively low ambient temperature, a pumping operation can be used, which would be quite sufficient. It is also clear that if the ambient temperature is equal to or higher than the internal temperature, at most only one climatic operation comes into question, since no cooling will take place in pumping operation.

The invention further comprises an air conditioning unit designed according to one or more of claims 1 to 7 for control cabinets with a very high IP protection class and with very low energy consumption.

Furthermore, the invention relates to a method for operating a cabinet air conditioner for cooling a cabinet, wherein in a compression operation of the cabinet air conditioner in a refrigerant circuit of the cabinet air conditioner refrigerant is compressed via a compressor to high pressure level and passed into a condenser and cooled there wherein heat energy is released to an environment, and is then expanded via an expansion valve, so that the refrigerant evaporates by absorbing heat energy via a heat receiving means, and further in an additional pumping operation of the cabinet air conditioner, the refrigerant is pumped without pressure change, so that a heat transfer is carried out by a heat-absorbing heat exchanger to a heat-emitting heat exchanger according to a heat exchanger principle, wherein both in the compression mode and in the pumping operation executed for both operations, the switching is provided in the pumping operation, the refrigerant via the condenser facing the environment, wherein the refrigerant is pumped in the pumping operation via a pump connected in parallel to the expansion valve, wherein the refrigerant in the pumping operation via a parallel to the Compressor connected bypass line is conveyed, wherein connected to an internal temperature sensor control device with respect to an interior of the cabinet temperature dependent between the compression mode and the Pumping operation switches or regulates, and / or wherein a control device connected to an ambient temperature sensor with respect to an ambient temperature dependent on a cooling operation, in particular a pumping operation, controls.

An embodiment will be explained in more detail with reference to the drawings, wherein further advantageous developments of the invention and advantages thereof are described.

Fig. 1

eine Darstellung eines Standard-Kältekreislaufs nach dem Stand der Technik,

Fig. 2

eine Darstellung eines erfindungsgemäßen Kältekreislaufs,

Fig. 3

eine perspektivische Darstellung eines Schaltschrankes mit einem Kühlmodul, und

Fig. 4

ein Blockschaltbild einer Regelvorrichtung des erfindungsgemäßen Kältekreislaufs.

Show it:

Fig. 1

a representation of a standard refrigeration cycle according to the prior art,

Fig. 2

a representation of a refrigeration cycle according to the invention,

Fig. 3

a perspective view of a cabinet with a cooling module, and

Fig. 4

a block diagram of a control device of the refrigeration cycle according to the invention.

Fig. 1 illustrates a standard refrigeration cycle of an air conditioner for use in a control cabinet. The air conditioner includes a refrigerant circuit with coolant lines L1 to L4. This circuit is used to execute a compression operation. A refrigerant is compressed by the line L1 via a compressor 11 to high pressure level. The rising

Temperature of the refrigerant. Thereafter, the refrigerant is supplied via line L2 to a condenser 12. As the refrigerant releases heat energy to the environment, it condenses to reach a liquid state. The heat release to the environment is indicated by the arrow A. The condenser 12 is in contact with the outside air.

The refrigerant still has high pressure in line L3. It is then expanded via an expansion valve 13. Via the line L4, the refrigerant is supplied to the evaporator 14, which is in contact with the air of the control cabinet. Here is a heat absorption of dissipated heat loss in the cabinet, which is indicated by the arrow B, the refrigerant evaporates.

This principle is also used by the invention. In addition, however, another cooling principle is provided. According to the invention, an additional pumping operation is present, which in Fig. 2 is illustrated. Here, the refrigerant is pumped around without pressure change, so that a heat transfer takes place according to a heat exchanger principle. The refrigerant circulates in a circle. Without a pump, the system works analogously to a gravity heater. At high transmitted power densities and suitable temperature conditions, evaporation or condensation processes can also occur during the heat exchange processes, which further increases the efficiency of the process.

Analogous to the circle according to Fig. 1 are the condenser 12 and the heat receiving means 14, which is designed as a heat exchanger 15, arranged. The heat exchangers 15 and 12 are designed both for the compression operation and for the pumping operation. In pumping operation, the refrigerant is pumped via the condenser 12 without pressure change, so that the heat dissipation takes place to the environment through the condenser.

As Fig. 2 shows, a bypass line L5 is connected parallel to the compressor. There is no compressor in this line L5. In pumping mode, the refrigerant is conveyed via this line L5. The line L5 is connected on the one hand to the lines L1a and L1b and on the other hand to the lines L2a and L2b. Parallel to the expansion valve 13, a pump 16 is connected, through which the refrigerant is pumped during pumping operation. In pumping operation, the refrigerant is pumped via the condenser 12, via the lines L6 or L6a, L6b and L4b, L1a, L5, L2b, L3a and L3b.

As before Fig. 2 illustrated, after the condenser 12, a collecting container 17 is connected for the liquid refrigerant collected therein. The collecting tank 17 is located between the lines L3a and L3b or between the condenser 12 and the branch to the expansion valve 13 or the pump 16. The pump 16 sucks liquid refrigerant from the collecting tank 17.

Preferably, the compression operation and the pumping operation are reversible. A changeover from the compression mode to pump mode and vice versa via shut-off valves.

Fig. 3 shows a cabinet 18 with an air conditioner 19. This can be designed as a cooling module 20 for modular expansion of the control cabinet. For example, the cooling module 20 may be disposed on and sealed to the cabinet so as to preclude ingress of water and dust into the cabinet. As a result, a high IP protection class can be realized. The device 19 may be provided with air inlet openings 21 and air outlet openings 22, wherein the arrows C, D illustrate an external air flow. This air flow can be by convection and / or by at least
a fan. In Fig. 3 is an example to be cooled component K shown.

In the control cabinet 18 circulates a closed air flow E, which can also be done by convection and / or by at least one fan.

Preferably, the outside air is not in contact with the air of the control cabinet in order to achieve the high IP protection class. The control cabinet is practically hermetically sealed.

In Fig. 4 a control device 23 is shown. To these are an internal temperature sensor S1 and / or an ambient temperature sensor S2, the compressor 11, the pump 16, and one or more shut-off valves V1 to Vn and the expansion valve 13 connected.

By the internal temperature sensor S1 with respect to the cabinet interior temperature-dependent control or switching from the compression mode to pumping operation and vice versa is achieved. For example, a pumping operation may be turned on at a low ambient temperature. A pumping mode can also be switched on with a low nominal actual value control deviation, while with a high nominal actual value control deviation, the air conditioning mode can be switched on. In pumping operation, for example, the cabinet temperature may be 35 ° while the ambient temperature is 20 °.

The ambient temperature sensor S2 creates a temperature-dependent cooling operation with respect to the ambient temperature. This is particularly favorable in pumping operation.

To exclude that heat is pumped from the outside in, it is expedient that a pumping operation only takes place when the ambient temperature is lower than the internal temperature.

The control device 23 may be designed so that a constant temperature is regulated in accordance with an adjustable or fixed setpoint of, for example, 35 °. If necessary, the control can turn on the compressor 11 or the pump 16 in case of deviations or control corresponding valves 13, V1 to Vn.

The invention is not limited to this example, so instead of a control cabinet analog another housing can be used. As a high pressure in the sense of the description, any pressure change is to be understood in which a significant increase in the temperature of the refrigerant occurs. Also conceivable are designs without an additional pump, wherein the compressor could take over the task of a pumping function without pressure change.

LIST OF REFERENCE NUMBERS

11

compressor

12

condenser

13

expansion valve

14

Heat absorption means

15

heat exchangers

16

pump

17

Clippings

18

switch cabinet

19

air conditioning

20

cooling module

21

Air inlet openings

22

Air outlet openings

23

control device

25

bypass lines

L1-L6

Coolant lines

S1

Interior temperature sensor

S2

Ambient temperature sensor

V1-Vn

Shut-off valves

Claims (8)

1. A switching device air conditioner (19) with a compressor (11), a condenser (12), an expansion valve (13), a heat absorbing means (14) and a cooling circuit for executing a compression operation, in which a cooling medium is compressed to a high-pressure level via a compressor (11) and is supplied to a condenser (12) and is cooled there, wherein thermal energy is released to an environment, and then is expanded via the expansion valve (13), so that the cooling medium evaporates by absorbing thermal energy through the heat absorbing means (14),
   wherein the switching device air conditioner (19) has an additional pumping operation, in which the cooling medium can be is transferred without pressure change, so that a heat transport from a heat absorbing heat exchanger to a heat releasing heat exchanger according to a heat exchanger principle occurs, and wherein in the pumping operation, the cooling means can be pumped via the condenser (12) facing the environment,
   wherein both in the compression operation and in the pumping operation a heat exchanger (15) facing the inside of the switching device is provided, which is configured for both operations and forms the heat absorbing means (14),
   wherein parallel to the expansion valve (13), a pump (16) is connected, through which in the pumping operation the cooling means can be conveyed,
   wherein parallel to the compressor (11), a bypass line (L5) is connected, through which in the pumping operation the cooling means can be conveyed,
   wherein an internal temperature sensor (S1) is provided as well as a control device (23) connected thereto, by means of which a control or switch from the compression operation to the pumping operation and vice versa occurs, which is dependent on temperature regarding the interior of the switching device, and/or an ambient temperature sensor (S2) is provided as well as a control device (23) connected thereto, by means of which a cooling operation, in particular a pumping operation, occurs, which is dependent on temperature regarding an ambient temperature.
2. A switching device air conditioner according to claim 1,
   characterized in that
   after the condenser (12) a collecting container (17) for the liquid cooling means is connected.
3. A switching device air conditioner according to one of claims 1 or 2,
   characterized in that
   in the pumping operation, the cooling means can be pumped via the condenser (12) without pressure change, so that a heat release to the environment takes place through the condenser (12).
4. A switching device air conditioner according to one of the preceding claims, characterized in that
   the compression operation and the pumping operation are configured switchable, wherein a switch from the compression operation to pumping operation and vice versa is executed via shut-off valves (V1 - Vn).
5. A switching device air conditioner according to one of the preceding claims, characterized in that
   a pumping operation occurs when the ambient temperature is lower than the internal temperature.
6. A switching device air conditioner according to one of the preceding claims, characterized by an embodiment as a module-like assembly.
7. A switching device air conditioner according to claim 1 for switching devices configured with a very high IP protection class with a very low energy consumption.
8. Method for operating a switching device air conditioner (19) for cooling a switching device, wherein in a compression operation of the switching device air conditioner (19) in a cooling circuit of the switching device air conditioner (19) a cooling medium is compressed to a high-pressure level via a compressor (11) and is supplied to a condenser (12) and is cooled there, wherein thermal energy is released to an environment, and then is expanded via an expansion valve (13), so that the cooling medium evaporates by absorbing thermal energy through a heat absorbing means (14),
   wherein in an additional pumping operation of the switching device air conditioner (19) the cooling medium is transferred without pressure change, so that a heat transport from a heat absorbing heat exchanger to a heat releasing heat exchanger occurs according to a heat exchanger principle, wherein both in the compression operation and in the pumping operation a heat exchanger (15) facing the inside of the switching device is provided, which is configured for both operations and forms the heat absorbing means (14), wherein in the pumping operation the cooling means is pumped via the condenser (12) facing the environment, wherein in the pumping operation the cooling means is conveyed via a pump connected parallel to the expansion valve (13), wherein in the pumping operation the cooling means is conveyed via a bypass line (L5) is connected parallel to the compressor (11), wherein a control device (23) connected to an internal temperature sensor (S1) switches or controls the compressing operation and the pumping operation dependent on temperature regarding the interior of the switching device, and/or wherein a control device (23) connected to an ambient temperature sensor (S2) controls a cooling operation, in particular a pumping operation, dependent on a temperature regarding an ambient temperature.

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