EP2199706A1 - Air conditioning device - Google Patents

Abstract

In an air conditioner (19) having a refrigerant circuit for performing a compression operation in which a refrigerant is compressed via a compressor (11) to high pressure level and in a condenser (12) passed and cooled there, wherein heat energy is released to an environment, and is subsequently expanded via an expansion valve (13) so that the refrigerant is further cooled and via a heat receiving means (14) heat absorption takes place, a total of less electrical energy is consumed. This is achieved by an additional pumping operation in which the refrigerant is umpumpbar without pressure change, so that a heat transfer takes place according to a heat exchanger principle.

Description

The invention relates to an air conditioner with a refrigeration circuit for performing a compression operation in which a refrigerant is compressed via a compressor to high pressure level and passed in a condenser and cooled there, wherein heat energy is released to an environment and is then expanded via an expansion valve,
wherein the refrigerant evaporates in the evaporator while absorbing heat.

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 Schait crane 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.

The invention has for its object to provide an 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 in that 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 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, vaporizing 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 essentially 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.

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

In an advantageous development of the air conditioner according to the invention it is provided that parallel to the compressor, a bypass line is connected, 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.

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 takes place in which the expansion valve can be closed during pumping operation, so that the fluid can flow only via the pump.

In a further advantageous embodiment of the invention, the refrigerant is pumped through the condenser in the pumping operation. 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.

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. Appropriately, the. Sump disposed between the branch to the pump and the expansion valve and the condenser.

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 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 13 for control cabinets with very high IP protection class and with very low energy consumption.

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

Figure 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, heat exchange processes can also lead to evaporation or condensation 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 L1 a and L1 b 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. 1 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 an example of a component K to be cooled is 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 operation can be switched on even with a low desired actual value control deviation, while at high target actual value control deviation, the air conditioning operation 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 (15)

An air conditioner (19) having a refrigerant circuit for performing a compression operation in which a refrigerant is compressed via a compressor (11) to high pressure level and in a condenser (12) passed and cooled there, wherein heat energy is released to an environment, and then on an expansion valve (13) is expanded so that the refrigerant evaporates by absorbing heat energy via a heat receiving means (14),
characterized by an additional pumping operation in which the refrigerant is umpumpbar without pressure change, so that a heat transfer from a heat-receiving heat exchanger to a heat-emitting heat exchanger takes place according to a heat exchanger principle. Air conditioner according to claim 1,
characterized,
in that parallel to the compressor (11) a bypass line (L5) is connected, through which the refrigerant can be conveyed during pumping operation. Air conditioner according to claim 1 or 2,
characterized,
in that parallel to the expansion valve (13) a pump (16) is connected, through which the refrigerant can be conveyed during pumping operation. Air conditioner according to one of the preceding claims 1 to 3,
characterized,
that in pump operation, the refrigerant on the side facing the ambient heat exchanger (condenser) (12) is pumpable. Air conditioner according to one of the preceding claims 1 to 4,
characterized,
that after the condenser (12) a collecting container (17) for the liquid refrigerant is connected. Air conditioner according to one of the preceding claims 1 to 5,
characterized,
that executed for both operations, the cabinet inner side facing the heat exchanger (15) is provided both in the compression mode and in the pumping operation. Air conditioner according to one of the preceding claims 1 to 6,
characterized,
that in the pumping operation, the refrigerant via the condenser (12) is pumpable without pressure change, so that takes place through the condenser (12) heat dissipation to the environment. Air conditioner according to one of the preceding claims 1 to 7,
characterized,
that the compression mode and the pumping operation are reversible, wherein a switchover from the compression mode to pumping operation and vice versa via shut-off valves (V1 - Vn) takes place. Air conditioner according to one of the preceding claims 1 to 8, characterized by an internal temperature sensor (S1) and an associated control device (23), wherein a respect to an interior temperature-dependent control or switching from the compression mode to pumping operation and vice versa. Air conditioner according to one of the preceding claims 1 to 9, characterized by an ambient temperature sensor (S2) and a control device (23) connected thereto, by means of which a relative to an ambient temperature-dependent cooling operation, in particular a pumping operation, takes place. Air conditioner according to one of the preceding claims 1 to 10,
characterized,
that a pumping operation is carried out when the ambient temperature is lower than the indoor temperature. Air conditioner according to one of the preceding claims 1 to 11, characterized by an embodiment as a cabinet air conditioner. Air conditioner according to one of the preceding claims 1 to 12, characterized by an embodiment as a module-like assembly. Method for cooling, in particular for cooling a control cabinet, with an air conditioner (19) according to one of the preceding claims 1 to 13. Use of an air conditioner according to one of claims 1 to 13 for running with very high IP protection class cabinets with a very low energy consumption.

Images