JPH0124521Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has first and second refrigeration cycles independent of each other, and the refrigerant condensed in the first refrigeration cycle having a user-side evaporator is transferred to the second refrigeration cycle. The present invention relates to an improvement of a refrigeration system that performs highly efficient operation by further cooling and absorbing heat by the user-side evaporator of the first refrigeration cycle.

Generally, during steady cooling operation of this type of refrigeration system, the temperature of the condensate refrigerant in the first refrigeration cycle having the user-side evaporator is relatively high, and the suction pressure of the second refrigeration cycle using this as a heat source is , becomes higher than the suction pressure of the first refrigeration cycle. on the other hand,
The volumetric efficiency of the compressor increases as the suction pressure increases, and accordingly, the volumetric coefficient increases, resulting in highly efficient operation. Therefore, rather than performing cooling operation with only one refrigeration cycle, by providing an auxiliary second refrigeration cycle and operating the second refrigeration cycle at a higher suction pressure than the first refrigeration cycle, high Efficient operation can be performed, and the operation rate of the first refrigeration cycle is reduced, resulting in energy savings. By the way, conventionally, since the second refrigeration cycle was always operated in conjunction with the first refrigeration cycle, for example, when starting the cooling operation after defrosting the user side evaporator of the first refrigeration cycle in winter, the second refrigeration cycle Even if the suction pressure of the second refrigeration cycle was lower than the suction pressure of the first refrigeration cycle, the second refrigeration cycle was operated, resulting in low efficiency operation. That is, when the refrigerant of the first refrigeration cycle is condensed in the air-cooled condenser, the condensation temperature in winter is lowered, for example, to about 5 to 10 degrees Celsius. On the other hand, immediately after the cooling operation after defrosting the user-side evaporator, the suction pressure of the first refrigeration cycle is relatively high, for example, 5°C.
There is considerable pressure. On the other hand, the second
Because the condensate refrigerant temperature in the first refrigeration cycle is low, the suction pressure of the refrigeration cycle becomes a pressure equivalent to 0°C, and therefore the second refrigeration cycle operates at a lower efficiency than the first refrigeration cycle. , second
There is no need to operate the refrigeration cycle.

This invention was made to eliminate such drawbacks, and will be explained below based on the drawings.

In the figure, 1 is the first refrigeration cycle;
The high-temperature, high-pressure gas refrigerant discharged from the compressor 2 is condensed and liquefied in the first condenser 4 having the first blower 3, and then depressurized in the first expansion device 5 and transferred to the first usage side. It is evaporated in the evaporator 6 and then inside the refrigerator (not shown).
After the air is cooled, it is sucked into the first compressor 2 again. 11 is a second refrigeration cycle, and the high-temperature, high-pressure gas refrigerant discharged from the second compressor 12 is passed through a second condenser 14 having a second blower 13.
A second evaporator 16 is disposed in a heat exchange relationship with a liquid pipe 7 through which the refrigerant is condensed and liquefied, then depressurized by a second expansion device 15 and condensed by the first condenser 14. After being evaporated and cooling the liquid refrigerant in the liquid pipe 7, it is sucked into the second compressor 12 again. 21 is a pressure detector that detects the suction pressure of the first compressor 2 and the second compressor 12, and when the suction pressure of the second compressor 12 is lower than the suction pressure of the first compressor 2, When this occurs, the entire second refrigeration cycle 11 including the second compressor 12 is stopped.

Next, the effect will be explained. During normal cooling operation, the temperature of the refrigerant condensed in the first condenser 4 is relatively high, and the evaporation temperature in the second evaporator 16 that exchanges heat with the refrigerant (the suction pressure of the second compressor 12) is relatively high. (almost the same) is the evaporation temperature in the first user evaporator 6 (the first
(almost the same as the suction pressure of compressor 2). Therefore, the pressure sensor 21 is not activated and the first,
Both second refrigeration cycles 1 and 11 are operated.
Next, when the first user-side evaporator 6 is defrosted, the inside of the refrigerator (not shown) that houses the first user-side evaporator 6 is
temperature and the pressure on the low pressure side of the first refrigeration cycle 1 rise. When the cooling operation is restarted in such a state, especially in winter, the condensing temperature in the first refrigeration cycle 1 is low, so the evaporation temperature in the second refrigeration cycle 2 also decreases, and the suction pressure of the second compressor 12 decreases. may be lower than the suction pressure of the first compressor 2. In such a case, this is detected by a pressure detector and the entire second refrigeration cycle 11 including the second compressor 12 is stopped to prevent low efficiency operation.

As described above, according to this invention, the first and second refrigeration cycles are independent of each other, and the refrigerant condensed in the first refrigeration cycle having the user-side evaporator is transferred to the second refrigeration cycle. When the suction pressure of the second refrigeration cycle is lower than the suction pressure of the first refrigeration cycle in a refrigeration system that further cools and causes the evaporator on the user side of the first refrigeration cycle to absorb heat from this cooling amount, , this is detected by a pressure detector and the operation of the second refrigeration cycle is stopped, so highly efficient operation is always performed.
The practical effects are great, such as improved operating efficiency.

[Brief explanation of drawings]

The figure is a refrigeration cycle diagram showing one embodiment of this invention. In the figure, 1 is a first refrigeration cycle, 2 is a first compressor, 4 is a first condenser, 5 is a first expansion device,
6 is a first utilization side evaporator, 11 is a second refrigeration cycle, 12 is a second compressor, 14 is a second condenser, 15 is a second throttle device, 16 is a second evaporator, 21 is a pressure sensor.

Claims (1)

[Scope of utility model registration request] A first compressor, a first condenser, a first throttle device, and a first user-side evaporator connected in sequence.
A refrigerant cycle, a second compressor, a second condenser, a second throttle device, and a second evaporator for further cooling the refrigerant condensed in the first condenser are connected in sequence. In the refrigeration system, the suction pressure of the first compressor and the suction pressure of the second compressor are detected, and the suction pressure of the first compressor is detected.
A refrigeration system comprising a pressure detector that operates the second refrigeration cycle only when the suction pressure of the compressor is higher than or the same as the suction pressure of the second compressor.