JPS5969663A - Refrigeration cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] FIELD OF THE INVENTION The present invention relates to frozen cyquiles.

Conventionally, the throttling device used in the refrigerant circuit of an air conditioner includes a capillary tube, but in order to control a refrigeration cycle using a variable capacity compressor, multiple capillary tubes are used to adjust the capacity of the compressor. If you switch over and use them as needed, you will not be able to achieve sufficient control.

In addition, conventional gas-type expansion valves detect the degree of superheating of the refrigerant at the outlet of the evaporator and control the flow rate of the refrigerant by adjusting the amount of throttling so that the degree of superheating at the outlet of the evaporator remains constant. exists, and the heat transfer coefficient of the superheated refrigerant gas is much smaller than the boiling heat transfer coefficient of the two-phase liquid/gas state, resulting in an inefficient operating state.

Furthermore, if the evaporator has multiple circuit branch circuits and the heat load differs for each circuit, the gas expansion valve detects and controls the degree of superheat of the refrigerant, so the circuit with the least heat load is The refrigerant flow rate is controlled accordingly, and in a circuit with a large heat load, superheated refrigerant occupies most of the circuit, which prevents effective use of the entire evaporator.

Furthermore, since conventional throttling devices control the degree of superheating at the outlet of the evaporator, they do not control the degree of supercooling at the outlet of the condenser. Either an excessive amount of liquid refrigerant has accumulated and the refrigerant condensation pressure has increased abnormally, or the refrigerant is not completely liquefied in the condenser and enters the throttling device in a gaseous state, reducing heating capacity.

The present invention was proposed in view of the above circumstances, and an object of the present invention is to provide a refrigeration cycle in which the evaporator and condenser are always well controlled in response to a wide range of changes in the flow rate of refrigerant discharged from the compressor. , compressors, condensers, thermoelectric expansion valves.

The refrigeration cycle includes an evaporator connected in a ring, and is characterized by comprising a thermoelectric expansion valve that operates by detecting the temperature in front of the condenser and the thermoelectric expansion valve.

An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a system diagram thereof, FIG. 2 is an enlarged vertical sectional view showing the thermoelectric expansion valve of FIG. 1, and FIG. 3 is the enthalpy pressure of the refrigerant in FIG. 1. 4 is a diagram showing the relationship between the heater voltage of the thermoelectric expansion valve of FIG. 2 and the refrigerant flow rate.

First, in Fig. 1, 1 is a variable capacity or constant speed compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a distributor, and 5 is a
．． 6. 7. 8 is a check valve, 10 is a thermoelectric expansion valve, 14 is a distributor, 15 is an indoor heat exchanger, 16 is an accumulator, 1.7 is an accumulator heat exchanger, 18 is a compressor suction pipe, 19 is a check The refrigerant that has passed through the valve 7 or the check valve 6 is connected to the accumulator heat exchanger 17 through piping, which is arranged so that it can exchange heat with the compressor suction pipe 18.

20 is an electronic control device; 21 is a temperature detection end installed in the center of the refrigerant pipe passing through the outdoor heat exchanger 3; 22 is a temperature detection end installed in the refrigerant pipe flowing into the thermoelectric expansion valve 10;
3 is a temperature detection end installed in the center of the refrigerant pipe passing through the indoor heat exchanger 15.

Next, in FIG. 2, the thermoelectric expansion valve 10 can be roughly divided into:
It is composed of a valve part 101 and a valve driving part 120, and the valve part 101 is composed of a valve stem 102 and a valve body 103.
02 is the valve seat portion 104. Outflow port 105. Inflow boat 1
06, and freezing tubes 107 and 108 are connected to each port 105 and 106, respectively. The valve body 103 is inserted into a hole 114 formed in the valve stem 102 so as to be slidable up and down. Meanwhile, the valve driving portion 120 is inserted into an upper casing 121, a lower casing 122, and so on. A sealed space 123 is formed by the valve stem 102, and two bimetals 124, 1 are arranged in the sealed space 123.
25 is stored, and one bimetal 124 and 125 are arranged in parallel with each other at both ends with spacers 126 and 127 interposed therebetween, and holes 128° and 129 are bored in the center of each, and they are fixed to the center of the inner surface of the upper casing 121. Support bin 1
30 is inserted from above into the hole 128 of the upper bimetal 124, and a pin portion 131 formed at the upper end of the valve body 103 is inserted from below into the hole 129 of the lower bimetal 125, and each is supported in the sealed space 123. Note that the valve body 103
is always urged upward by a spring 133 via a seat 132. 134 is an electric heater that forcibly heats the upper bimetal 124, and is wound around the upper bimetal 124. 135° and 136 are terminals connected to both ends of the electric heater 134, respectively, and the upper casing 121.
The upper bimetal 12-4 provided through the spacers 126, 127, . The valve body 103 is pushed down against the spring 133 via the bimetal 125, and the space between the valve seat 104 and the lower end of the valve body 103 is moved in the valve closing direction.

In this case, the opening degree of the valve is adjusted by the amount of electric power applied to the electric heater 134, and as shown in FIG. Conversely, when the electric power to the electric heater 134 is small, the amount of deformation of the upper bimetal 124 is small and the opening degree of the valve is large. The lower bimetal 125 deforms under the influence of the temperature of the refrigerant flowing into the closed space 123 from the sliding surface between the hole 114 and the valve body 103 and the ambient air temperature, and is made of a bimetal for load condition compensation.

In such a device, during cooling operation, the refrigerant flows as shown by the solid arrow in Fig. 1, and at this time, the outdoor heat exchanger 3 operates as a condenser, and the indoor heat exchanger 15 operates as an evaporator. During the heating operation, the refrigerant flow is controlled by the four-way valve 20, as shown by the dashed arrow in the figure.
Due to this action, the indoor heat exchanger 15 moves in the opposite direction to that during cooling operation, and operates as a condenser to heat the room.

Typical operating conditions at that time are shown in the pressure (p)-enthalpy (i) diagram in Figure 3. During cooling operation, first, the high-temperature, high-pressure discharged refrigerant (in state a) discharged from the compressor 1 is ) reaches the outdoor heat exchanger 3 via the four-way valve 2, where it is condensed and liquefied, and the state of the refrigerant at this time is as follows. Furthermore, the refrigerant is distributed through the distributor 4. Pass through the reverse ft valve 6 and connect the suction pipe 1 in the piping 19.
It exchanges heat with the liquid refrigerant in the accumulator 16 in the accumulator heat exchanger 17 and becomes supercooled to state D, and then the pressure is reduced by the thermoelectric expansion valve 10. , expansion state e), check valve 89
The state f is evaporated in the indoor heat exchanger 15 through the distribution pipe 14.
), enters the accumulator 16 via the four-way valve 2, is heated in the accumulator heat exchanger 17 (state g), and is further heated in the piping 19 as it passes through the suction pipe 18 (state h), and then flows into the compressor 1. It gets sucked in.

Next, during heating operation, the refrigerant is pumped through the compressor 1° four-way valve 2. Indoor heat exchanger 15. Distribution pipe 14° check valve 7. Piping 19. Accumulator heat exchanger 17. Thermoelectric expansion valve 10. Check valve 5
Distributor 4° Outdoor heat exchanger 3. Four-way valve 2. Accumulator 16, piping 18. It circulates in the order of compressor 1.

Thus, the operating state shown in FIG. 3 can be easily achieved by appropriately selecting the capacity of the thermoelectric expansion valve 10 and the amount of refrigerant in the refrigeration cycle.

Therefore, in the present invention, depending on the circulating amount of refrigerant discharged from the compressor 1, the condenser (outdoor heat exchanger 3 for cooling, indoor heat exchanger 15 for heating) and the evaporator (indoor heat exchanger for cooling) Vessel 1
5. During heating, there is a thermoelectric expansion valve 10 as a throttling device for optimally operating the outdoor heat exchanger 3), which performs the following operations.

First, during cooling operation, the temperature t1 detected by the temperature detection end 21 installed in the center of the refrigerant pipe passing through the outdoor heat exchanger 3 and the temperature detection end installed in the high pressure pipe just before the thermoelectric expansion valve 10 The temperature t2 detected by 22 is set to 1 within the electronic control device 20. -12, that is, the degree of subcooling, to a predetermined value Δtc.
The voltage supplied to the electric heater 134 inside the thermoelectric expansion valve 10 is controlled, thereby changing the throttle amount of the thermoelectric expansion valve 10 and controlling the refrigerant flow rate.

At this time, when the value of j+t2 is larger than the set value Δtc, the voltage supplied to the electric heater 134 of the thermoelectric expansion valve 10 is reduced, so the opening degree of the thermoelectric expansion valve 10 begins to increase. -12 decreases, and on the other hand, when the values t and -t2 are smaller than the set value Δtc, the voltage supplied to the electric heater 134 of the thermoelectric expansion valve 10 is increased, so the opening degree of the thermoelectric expansion valve 10 is increased. starts to decrease and the value of j+L2 increases.

In this way, the opening degree of the thermoelectric expansion valve is automatically adjusted so that the subcooling degree t, -t2 before the thermoelectric expansion valve is set to the set value ΔtcK'&.

Next, during heating operation, the temperature t detected by the temperature detection end 23 installed in the center of the refrigerant pipe passing through the indoor heat exchanger 15, and the temperature t installed in the high pressure pipe immediately before the thermoelectric expansion valve 10 The temperature t2 detected by the detection end 22 is.

Within the electronic control unit 20, the voltage supplied to the electric heater 134 within the thermoelectric expansion valve 10 is controlled so that the value of 13-12, that is, the degree of subcooling, is a predetermined value Δ1++, and thereby the thermoelectric expansion valve 10 The amount of throttling changes to control the refrigerant flow rate.

At this time, the values of Δtc and Δt u vary depending on the amount of heat exchanged between the accumulator heat exchanger 17 and the pipes 18 and 19, but as shown in FIG. B, the degree of supercooling can be set from the degree of supercooling between d and b when state d is reached in front of the thermoelectric expansion valve.
In normal cooling and heating operations, the temperature is about 20 to 30'C.

According to such a device, the following effects can be achieved.

(1) Since the opening degree of the thermoelectric expansion valve is adjusted so that the degree of subcooling remains constant during both cooling and heating, a large amount of liquid refrigerant accumulates in the condenser, causing an abnormal increase in condensing pressure. Furthermore, the refrigerant does not liquefy in the condenser and enters the throttling device in a gaseous state, thereby preventing damage to the heat dissipation ability of the condenser, allowing the condenser to be used effectively under a wide range of conditions.

(2) For the evaporator, the refrigerant is in a liquid-gas mixed state (third
The refrigerant exits the evaporator at point f in Figure 3 and flows into the accumulator 16 in a liquid-gas mixed state, and these liquid refrigerants are heated in the accumulator heat exchanger 17 (point g in Figure 3).
point) Furthermore, heat is exchanged with the high pressure pipe 19 in the suction pipe 18,
The gas is sucked into the compressor in a state close to saturated gas (third point).

For this reason, in the past, because the degree of superheating of the evaporator was controlled, superheated refrigerant gas existed at the outlet of the evaporator, resulting in a low heat transfer coefficient on the refrigerant side, making it impossible to operate the evaporator effectively. In the present invention, the refrigerant leaves the evaporator in a liquid-gas mixed state, making it possible to operate the evaporator effectively.

This is true even if the evaporator is branched into multiple circuits, as shown in Figure 1, and the heat load for each circuit is different.

To enable an evaporator to operate effectively without being affected by superheat degree control.

(3) As shown in Figure 1, four reverse valves 5° 6.7
．． Since the circuit is formed using thermoelectric expansion valves 10 and temperature detection terminals 21, 22.8 for both cooling and heating.
23 and the electronic control device 20, the configuration of the refrigeration circuit is simplified and the cost becomes low.

As described above, the present invention uses a variable capacity compressor in which the refrigerant flow rate can be varied over a wide range by controlling the degree of subcooling of the refrigerant before the expansion valve to be constant using the thermoelectric expansion valve 10. Even when a constant speed compressor is used under a wide range of operating conditions, the condenser and evaporator must be operated effectively to achieve efficient air conditioning, and the compressor may not be overheated or the liquid may return. It is advantageous in terms of lifespan as it reduces
In addition, only one diaphragm device is needed for both heating and cooling.
Cost can be reduced.

In short, according to the invention, a compressor, a condenser.

In a refrigeration cycle in which a thermoelectric expansion valve and an evaporator are connected in a ring, the thermoelectric expansion valve is activated by detecting the temperature in front of the condenser and thermoelectric expansion valve, resulting in high-performance, low-cost refrigeration. The present invention is industrially extremely useful because of the cycle.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing one embodiment of the present invention, and Fig. 2 is a system diagram showing an embodiment of the present invention.
3 is an enthalpy pressure diagram of the refrigerant in FIG. 1, and FIG. 4 is a line showing the relationship between the heater voltage and refrigerant flow rate of the thermoelectric expansion valve in FIG. 2. It is a diagram. 1. Compressor, 2. Four-way valve, 3. Outdoor heat exchanger,
4. Distributor, 5. 6. 7. 8. Reverse valve, 10
...Thermoelectric expansion valve, 14.. Distribution pipe, 15.. Indoor heat exchanger, 16.. Accumulator, 17.. Accumulator heat exchanger, 18.. Compressor suction pipe, 19.. Piping, 2
0...Electronic control unit, 21, 22.23...Temperature detection end, 101...Valve portion, 102...Valve stem, 103...Valve body, 104...Valve seat, 105...Outflow boat, 106・
・Inflow port, 107゜108... Freezer pipe, 114...
Hole, 120... Valve drive part, 121... Upper casing,
122... Lower casing, 123... Closed space, 124
．． 125... Bimetal, 126, 127... Spacer, 128.129... Hole, 130... Support pin, 131...
・Bin part, 132...Seat, 133...Spring, 134...Electric heater, 135
．． 136...Terminal, Sub-Agent Patent Attorney Masafumi Tsukamoto

Claims (1)

[Claims] An air refrigeration cycle consisting of a compressor, a condenser, a thermoelectric expansion valve, and an evaporator connected in a ring, comprising a thermoelectric expansion valve that operates by detecting the temperature in front of the condenser and the thermoelectric expansion valve. harmonizer.