JPH0379969A - Two-stage compression refrigeration cycle - Google Patents

Abstract

PURPOSE:To enable raising the temperature of the air ejected in indoor heating and also suppling hot water by providing between a lower-stage compressor and a higher- stage compressor a vortex tube whose higher-temperature outlet is connected to a second condenser and whose lower-temperature outlet is connected to the higher-stage compressor. CONSTITUTION:The refrigerant gas discharged at a medium pressure from a lower- stage compressor 9 flows into the inlet of a vortex tube 11, inside which a swirl develops and separates into higher-temperature gas and a lower-temperature gas; the higher-temperature gas, whose temperature is much higher than the temperature of the medium-pressure refrigerant gas entering the vortex tube 11, flows out through an outlet on the high temperature side and into an indoor heat exchanger 16 to be used for heating air and then condenses into liquid, whereas the lower-temperature gas, whose temperature is much lower than the temperature of the medium-pressure refrigerant gas entering the vortex tube 11, flows out through an outlet on the low temperature side, is sucked into a higher-stage compressor 10 to undergo compression from medium pressure to high pressure, and then flows into a hot water-supplying heat exchanger 12 to be used for heating water and then condenses into liquid. By providing a single vortex tube a simple structure is rendered capable of raising the temperature of indoor heating higher and supplying hot water.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to refrigeration cycles used in air conditioners, etc., and particularly relates to two-stage compression refrigeration cycles. When the ratio of evaporation pressure to condensation pressure (compression ratio) is large, two compressors are connected in series to prevent a rise in discharge temperature and to improve compressor efficiency.
Although two-stage compression refrigeration cycle equipment that compresses water in stages is widely used, there has recently been an increasing need in the market for multifunctional pumps that can operate air conditioning, heating, and hot water supply at the same time. Conventional example (Special Public Service 1986)
-48824) Aiku Figure 3 is a configuration diagram of a conventional refrigeration cycle when heating and hot water supply are operated simultaneously, where 1 is a low-stage compressor, 2 is a high-stage compressor, and 3 is a heat exchanger for hot water supply. 4 and 5 are the first and second throttling devices, respectively. 6 is the outdoor heat exchanger. They are connected in order in a ring to form a hot water supply circuit. ．． Reference numeral 7 denotes a third throttle device, which is provided on a pipe connecting the outlet of the hot water supply heat exchanger 3 and the suction pipe of the high-stage compressor 2. Further, 8 is an indoor heat exchanger, whose population is connected to the discharge pipe of the low-stage compressor l, and its outlet is connected to the pipe between the first throttle device 4 and the second throttle device 5. Stage side compressor 1, indoor heat exchanger 8,
Even if a heating circuit is configured by the second expansion device 5 and the outdoor heat exchanger 6, a part of the intermediate pressure refrigerant gas discharged from the low-stage compressor l is branched off for indoor heat exchange. The remaining refrigerant gas, which is discharged from the low-stage compressor l, is sucked into the high-stage compressor 2, where it is compressed to a high pressure to supply hot water. The liquid refrigerant flows into the indoor heat exchanger 3, contributes to hot water supply, liquefies itself, merges with the liquid refrigerant exited from the indoor heat exchanger 8, which is throttled by the first throttle device 4, and flows into the second throttle device 5. There, the air is throttled down to a low pressure, absorbs heat from the outside air in the outdoor heat exchanger 6, becomes a gas, and is sucked into the low-stage compressor 1 again. Here, a part of the refrigerant liquid discharged from the hot water supply heat exchanger 3 is throttled to an intermediate pressure by the third throttle device 7 and merges with the discharge gas of the low stage compressor 1, so that the high temperature The suction gas temperature of the stage side compressor 2 can be lowered,
The invention seeks to solve this problem by providing a system that can provide high-temperature hot water at the same time as heating operation without causing the discharge gas temperature of the high-stage compressor 2 to become abnormally high even in hot water supply operation with a high compression ratio. However, in the conventional example described above (when trying to operate with high efficiency when both heating and hot water heating are operated at the same time),
If the heating air outlet temperature becomes low, or if an attempt is made to increase the air outlet temperature, the compression ratio on the high stage side becomes much smaller than that on the low stage side, resulting in an unbalanced compression ratio and poor system efficiency. When operating a two-stage compression refrigeration cycle, it is desirable to operate the cycle at an intermediate pressure where the compression ratios on the upper and higher stages are approximately the same, and the coefficient of performance of the equipment is high. It is well known that this happens and that if you try to use the same compression ratio to obtain hot water on the high stage side, the condensation temperature at the intermediate pressure will become low, causing the heating to blow out. The temperature becomes so low that it cannot be used for practical purposes.In order to solve this problem, if we try to raise the condensing temperature by partially raising the intermediate pressure, the compression ratio on the high stage side is very small compared to the low stage side ( For example, in the case of Freon R22, a commonly used refrigerant, the evaporation temperature of the outdoor heat exchanger during normal heating operation is O''q. The condensing temperature of the vessel is 50
°Ω Suppose the condensing temperature of the heat exchanger for hot water supply is 70°C. The compression ratio on the low stage side is approximately 3.9°, the compression ratio on the high stage side is approximately 1.5, and the compression ratio between the low stage and high stage is As a result, the balance between the
Since the suction specific volume on the high stage side is also very small, the cylinder volume of the high stage compressor must be made considerably smaller than that on the low stage side, which poses many design difficulties. Since the high-pressure liquid refrigerant was throttled down to an intermediate pressure and flowed directly into the suction side of the high-stage compressor, it was difficult to control the liquid flow rate, and there were concerns about liquid compression. The present invention aims to solve the problems of the prior art, but the two-stage compression of the present invention is a means for solving the problems. Refrigeration cycle (partner) At least low-stage compressed air High-stage compressor 1st condensing device 2nd condenser, 1st throttling device 2nd throttling device The main circuit consists of the evaporator, the low-stage compressor and the high-stage compressor A vortex tube is installed between the compressor and the high-temperature side outlet of the vortex tube is connected to the second condenser, and the low-temperature side outlet is connected to the high-stage compressor. The device is characterized in that a gas-liquid separator is provided between the throttle device and the second throttle device, and is connected to the inlet of the high-stage compressor. The high-pressure refrigerant gas flows into the vortex tube inlet, where a swirling flow occurs and is split into high-temperature gas and low-temperature gas.
The high-temperature gas (upper) exits from the high-temperature side outlet and flows into the indoor heat exchanger, which is the second condenser, where it contributes to heating.
The low-temperature gas comes out from the low-temperature side outlet, is sucked into the high-stage compressor, is compressed from intermediate pressure to high pressure, and flows into the first condenser, the hot water heat exchanger, where it contributes to hot water supply. The gas with a high degree of superheat flowing into the indoor heat exchanger is In addition, the temperature of the intake gas of the high-stage compressor can be lowered by using the vortex tube, so the temperature of the discharge gas of the high-stage compressor can be lowered even though the pressure is high. It is possible to supply hot water at a low temperature while simultaneously operating hot water for heating while maintaining the safety of the compressor and the coefficient of performance. The figure shows a two-stage compression refrigeration cycle in one embodiment of the present invention, where 9 is the low stage compression number 10 is the high stage compression a, 11 is the vortex tube, 12 is the hot water supply heat exchanger 1, and 13 is the first throttle. Device 14 is a second squeezing device
15 is an outdoor heat exchanger, each connected in turn in a ring shape.
Is it okay to configure a hot water supply circuit? ,, 16 is an indoor heat exchanger, whose population is connected to the high temperature side outlet of the vortex tube 11, and its outlet is connected to the first
It is connected to the piping between the expansion device 13 and the second expansion device 14, and the low-stage compressor 9, the vortex tube 11.
The indoor heat exchanger 16, the second expansion device 14, and the outdoor heat exchanger 15 constitute a heating circuit, with the indoor heat exchanger 16 at intermediate pressure and the hot water supply heat exchanger 12 at high pressure for two-stage compression. Although the refrigeration cycle is configured, the operating method of the two-stage compression refrigeration cycle configured in this way will be explained. The intermediate pressure refrigerant gas discharged from the lower stage compressor 9 flows into the inlet of the vortex tube 11 and the A swirling flow is generated inside and is branched into high-temperature gas and low-temperature gas.The high-temperature gas has a temperature considerably higher than that of the intermediate-pressure refrigerant gas that entered the vortex tube 11, and exits from the high-temperature side outlet to the indoor heat exchanger. 16 and contributes to heating there.
Although it condenses and liquefies itself, the low-temperature gas becomes considerably lower than the temperature of the intermediate-pressure refrigerant gas that flows into the vortex tube 11, exits from the low-temperature side outlet, is sucked into the high-stage compressor 10, and is compressed from intermediate pressure to high pressure. It flows into the hot water supply heat exchanger 12 and contributes to hot water supply, condensing and liquefying itself. Here, the coefficient of performance is high t, k. L if you drive! The condensation temperature can be lowered.The high-superheated gas heated in the vortex tube 11 can raise the heating blowout temperature in the indoor heat exchanger 16.Also, the high-stage compressor 10 The temperature of the suction gas can be lowered than that of the discharge gas of the low-stage compressor 9, and the temperature of the discharge gas of the high-stage compressor 10 can be kept low, making it possible to supply high-temperature hot water.In this way, one vortex tube is used. By providing this, high-temperature heating and high-temperature hot water supply can be achieved with a simple configuration, and the discharge gas temperature of the high-stage compressor, which is a safety issue, will not become abnormally high, and the safety of the compressor will be improved. Simultaneous operation of heating and hot water supply while maintaining a high coefficient of performance can be realized.Another embodiment of the present invention will be explained with reference to FIG.
In FIG. 2, the parts indicated by the same numbers as in FIG. 1 have the same functions, and the explanation will be omitted. 17, and even though the two-phase refrigerant from the first expansion device flows inside, the piping between the low-temperature side outlet of the vortex tube 11 and the suction side of the high-stage compressor 10 is placed in the middle. It is designed to exchange heat with the two-phase refrigerant inside the pressure heat exchanger 17, and by doing so, not only cooling in the vortex tube 11 but also heat exchange in the intermediate heat exchanger 17 causes suction of the high-stage compressor lO. Although the gas can be reliably cooled, the present invention does not require the power shown in the above embodiments.
For example, in the above embodiment, the intake gas of the high-stage compressor 10 is cooled by indirectly exchanging heat with the intermediate heat exchanger 17. A configuration in which the phase refrigerant flows directly into the suction side of the high-stage compressor 10 is also considered.These are included in the present invention.In the above embodiment, the low-stage compressor and the high-stage compressor are separated. It is obvious that the two-stage compression of the present invention can be performed using an integrated two-stage compressor (with the same shell), and these are also included in the present invention.As described above, the two-stage compression of the present invention Refrigeration cycle (Friend) A vortex tube is installed between the low-stage compressor and the high-stage compressor to configure a two-stage compression refrigeration cycle, so the desired low ratio and high-stage compression ratio are the same in a two-stage compression refrigeration cycle. However, the temperature of the refrigerant gas in the indoor heat exchanger can be increased by the vortex tube in an operating state where the intertransfer pressure is relatively low. Since the gas is also cooled by the vortex tube, there is no possibility that the discharge temperature of the high-stage compressor will rise even when high-temperature hot water is desired to be supplied, and the effect is that safe operation with a high coefficient of performance can be achieved. By placing an intermediate heat exchanger between the first throttle device and the second throttle device, combined with the cooling effect of the vortex tube, it is possible to reliably cool the intake gas of the high stage compressor.

[Brief explanation of drawings]

Fig. 1 shows the configuration of a two-stage compression refrigeration cycle according to an embodiment of the present invention. Fig. 2 shows the structure of a two-stage compression refrigeration cycle according to another embodiment of the invention. Fig. 3 shows a conventional two-stage compression refrigeration cycle. In the configuration diagram, Amo 9...low stage side compression @ 10... high stage side compressor 11
... Heat exchanger for hot water supply 12 ... First throttle device t, 1
3...Second expansion device 14...Indoor heat exchanger 1
5...Third expansion device 16...Indoor heat exchanger 1
7...Intermediate heat exchanger

Claims (2)

[Claims] (1) A main circuit is composed of at least a low-stage compressor, a high-stage compressor, a first condenser, a second condenser, a first throttle device, a second throttle device, and an evaporator, and the low-stage compressor A vortex tube is provided between the compressor and the high stage compressor, a high temperature side outlet of the vortex tube is connected to the second condenser inlet, and a low temperature side outlet is connected to the high stage compressor inlet. A two-stage compression refrigeration cycle featuring: (2) An intermediate heat exchanger is provided between the first expansion device and the second expansion device, and the refrigerant between the low temperature side outlet of the vortex tube and the high stage side compressor inlet is transferred to the refrigerant inside the intermediate heat exchanger. 2. The two-stage compression refrigeration cycle according to claim 1, wherein heat is exchanged directly or indirectly with the refrigeration cycle.