JPS5847967A - Refrigerating cycle of air conditioner - 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 The present invention relates to a refrigeration cycle for an air conditioner, particularly a refrigeration cycle for a separate air conditioner.
The purpose is to increase efficiency and improve followability to load fluctuations.

Conventionally, the main refrigeration cycle used in air conditioners consists of a compressor 1a, an outdoor heat exchanger (
condenser) 2a, pressure reducing device 3a such as capillary pipe etc.
, an indoor heat exchanger (evaporator) 4a are connected in an annular manner through piping. In addition, the power supply for air conditioners is generally designed to share 5°Hz and e o Hz; The refrigeration cycle is designed so that

However, when operating at 60 Hz, the discharge flow rate of the compressor 1a becomes smaller than when operating at 60 Hz, the pressure reducing effect of the pressure reducing device 3a becomes smaller, and a large amount of refrigerant flows into the indoor heat exchanger 4a, so that the compressor The degree of superheating of the refrigerant sucked into 1a is smaller than in the case of eoHz operation. The efficiency of the refrigeration cycle is affected by the degree of superheating, and the degree of superheating is approximately 6.
It shows the highest value at about 10 deg to 10 deg. However,
Since the degree of superheating is different between 50Hg operation and 6oHz operation as shown in -F, each frequency has to be used at a compromise, and it is often not possible to operate at the highest efficiency point of operation at each frequency.

In addition, when the indoor load increases by L, the indoor heat exchanger 4
Although the capacity of the pressure reducing device 3a increases, commensurately,
Since the amount of refrigerant supplied to the compressor 1a does not increase, the degree of superheating of the refrigerant sucked into the compressor 1a increases significantly, and deviates from the maximum efficiency point.

Furthermore, when the degree of superheating of the refrigerant increases significantly as described above, the temperature of a part of the indoor heat exchanger 4a increases due to superheated steam, and high temperature and high humidity air passes through the indoor heat exchanger 4a. In this case, the disadvantage was that dew condensation formed on the fan and wind cylinder.

To compensate for these shortcomings, conventionally, as shown in Fig. 2, a refrigeration cycle has been used which incorporates a temperature-type automatic expansion valve 6a that senses the temperature of the suction pipe 6a of one compressor 1a and adjusts the amount of pressure reduction. However, in a separate air conditioner that has an outdoor unit and an indoor unit, the indoor heat exchanger (evaporator) 4a and compressor 1
If the pressure loss between a and a is large, it is necessary to add a mechanism 9a that detects the pressure near the heat sensitive part 8a and use an external pressure equalization temperature automatic expansion valve 6a that operates based on both pressure and temperature. This is not only expensive, but also causes various problems, such as the refrigeration cycle becoming unstable and a hunting phenomenon depending on the thermal state of the heat-sensitive part 8a, and the mechanism being complex and having moving parts, which often result in failures. It had drawbacks.

In addition, as shown in FIG. 3, a liquid receiver 10 for storing refrigerant
A is connected between the pressure reducing device 3a and the indoor heat exchanger 4a, and the suction pipe 6a of the compressor 1a is passed through the liquid receiver 10a, and the refrigerant is stored in the liquid receiver according to the load. A refrigeration cycle that adjusts the amount of refrigerant circulating in the refrigerant circuit to the optimum level by changing the proportion of the liquid phase (for example, when the temperature of the suction pipe 6a rises, the refrigerant in the liquid receiver evaporates and the liquid phase A refrigeration cycle is known in which the degree of superheat is adjusted by increasing the amount of refrigerant circulated in the refrigerant circuit, but the one-separation type air conditioner has an internal and external connection pipe 7a,
Since this connecting pipe 7a works as a part of the pressure reducing device, the saturation temperature for the pressure at the outlet of the pressure reducing device 3a is higher than when the air conditioning load increases and the temperature of the suction pipe 6a becomes high. However, there was a drawback that the receiver remained filled with supercooled liquid and the amount of refrigerant could not be adjusted.

The present invention solves the drawbacks of the conventional refrigeration cycle described above, and one embodiment of the present invention will be described below with reference to FIGS. 4 and 6.

FIG. 4 is a refrigeration cycle diagram of a separate air conditioner showing an embodiment of the present invention, where A is an outdoor unit and B is an indoor unit. These two knits are connected by connecting pipes 9 and 1o. 1 is a compressor, 2 is an outdoor heat exchanger (
3 is a pressure reducing device such as a capillary tube,
4 is an indoor heat exchanger (evaporator), 6 is a suction pipe of the compressor 1, and these are connected in an annular manner in the order shown. Reference numeral 6 denotes a liquid receiver for storing refrigerant, through which a suction pipe 6 passes, as shown in FIG. Reference numeral 8 denotes an electric heater, which is wound around the outer periphery of the liquid receiver 6.

Next, to explain the adjustment of the amount of refrigerant, it is assumed that the refrigerant circuit of the air conditioner is currently filled with the required amount of refrigerant at the time of maximum load.

Generally, when the refrigerant circuit of a refrigeration system is filled with refrigerant in an amount appropriate for the load, the temperature of the suction pipe is maintained at a certain temperature.

Therefore, the temperature threshold of the suction pipe 6 is maintained at a certain temperature while the above-mentioned device is operated under the optimum chrysanthemum conditions. In this case, at point The temperature is higher than that of the suction pipe 6. Therefore, the liquid refrigerant is condensed inside the liquid receiver 6, and the liquid accumulates at a certain height. The liquid receiver 6 is equipped with an electric heater 8 as described above.
Since the refrigerant is wound around the refrigerant, when a certain current is passed through the electric heater 8, heat is generated and the refrigerant evaporates on the inner surface of the receiving liquid temperature 6. That is, within the receiving liquid temperature 6, condensation by the suction pipe 6 and evaporation due to heat generated by the electric heater 80 are balanced, so that the degree of superheating of the medium at the liquid level decreases, and the temperature of the suction pipe 6 increases.

Therefore, the amount of condensation in the liquid receiver 6 through which the suction pipe 6 passes increases, and the liquid level is higher than 7 (lance).As a result, the mass of the refrigerant contained inside the liquid receiver 6 is This increases compared to before the decrease.This increased refrigerant is the refrigerant that has flowed into the receiving liquid temperature 6 through the circuit, so excess cooling in the refrigerant circuit has been removed. The temperature of the suction pipe 6 approaches the original optimum value.

On the contrary, when the load increases above a certain load condition, the temperature of the suction pipe 6 rises and the amount of condensation in the liquid receiver decreases, causing the liquid to drain at a lower level. This means that the effective amount of refrigerant in the refrigerant circuit has increased,
The temperature of the suction pipe 6 approaches the original optimum value.

As is clear from the fear, the suction pipe 6
As the temperature changes, the amount of liquid in the receiver 6 is controlled by the balance between condensation and evaporation of the refrigerant Q in the receiver 6, and the amount of refrigerant in the refrigeration cycle is always kept at the optimum value. .

FIG. 6 shows an example of the specific structure of the liquid receiver 6. The liquid receiver 6 can be constructed by penetrating the suction pipe 6 into a pipe with a large diameter and making both ends flat for comparison. It can be easily produced.

Further, the amount of condensation and evaporation in the receiver e can be easily adjusted by appropriately selecting the diameter of the suction pipe 6 and the amount of heat generated by the electric heater.

As is clear from the above description, the present invention connects a compressor, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger in an annular manner, and a liquid receiver is provided between the pressure reducing device and the indoor heat exchanger. concatenate,
The suction pipe of the compressor is passed through the liquid receiver of the compressor for heat exchange, and a heating element is attached to the receiver for heat exchange. When the amount of refrigerant is appropriate, the amount of refrigerant in the liquid receiver is balanced at a liquid level where condensation occurs in the suction pipe at a temperature lower than the saturation temperature for the pressure at the outlet of the pressure reducing device, and evaporation occurs at a high temperature due to the heating element. However, if the load decreases, the temperature of the suction pipe will decrease, and the amount of condensation will increase, and the amount of refrigerant in the receiver will increase, reducing the amount of refrigerant in the refrigerant circuit. The amount of refrigerant in the refrigerant circuit decreases and the amount of refrigerant in the refrigerant circuit increases, making it possible to maintain an appropriate amount of refrigerant in the refrigerant circuit depending on the load, regardless of the load conditions compared to conventional systems. An efficient refrigeration system can be provided. In addition, since it is possible to prevent liquid refrigerant from returning to the compressor during low loads, it is possible to prevent compressor failure due to liquid compression. If this happens, the problem of uncondensed water packets condensing on the fan or wind barrel will be eliminated. Furthermore, compared to conventional superheat control devices using thermostatic automatic expansion valves, the structure is simpler and there are no moving parts, so there are fewer failures and it can be manufactured at an extremely low cost. It has various advantages in that control to promote evaporation can be easily carried out by changing the capacity of the heating element in order to balance the

[Brief explanation of the drawing]

1, 2, and 3 are refrigeration cycle diagrams showing different conventional examples, FIG. 4 is a refrigeration cycle diagram of an air conditioner showing an embodiment of the present invention, and FIG. 1... Compressor, 2... Outdoor heat exchanger, 3... Pressure reducing device, 4... Indoor heat exchanger, 6... ... Suction pipe, 6 ... Liquid receiver, 7 ... Connection pipe. 8... Heating element. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure ai Figure 2 Figure 3

Claims (1)

[Claims] A compressor, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger are each connected in a ring 11, a liquid receiver is connected between the +1° position and the indoor heat exchanger, A refrigeration cycle for an air conditioner, wherein a suction pipe of the compressor is disposed in the liquid receiver for heat exchange, and a heating element is disposed in the liquid receiver for heat exchange.