JPH026985B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration method and a refrigeration device for carrying out the same, which has a large energy saving effect particularly under conditions where the temperature of the cooling fluid of refrigerant gas is low, and is therefore suitable for use in areas with large outside temperature differences. The present invention relates to a refrigeration method and a refrigeration apparatus suitable for use in .

FIG. 1 shows a conventional water-cooled turbo refrigeration system. In the conventional water-cooled centrifugal refrigeration system shown in FIG.
Introduced within 2. The condenser 2 cools, condenses, and liquefies the refrigerant gas outside the heat exchanger tubes 2a by a cooling fluid flowing through the heat exchanger tubes 2a arranged in a large number therein. At this time, in order to perform an effective condensation action in the condenser 2, the high pressure gas is introduced from the top of the condenser 2, and the condensed liquid is configured to flow out from the bottom.

The condensed liquid of the refrigerant gas flows into the evaporator 4 through the throttle (pressure reducing device) 3, exchanges heat with the fluid flowing through the heat transfer tube 4a, becomes evaporated gas, and is sucked into the compressor 1 again.

In addition, in order to cool the motor 6 and oil cooler 7 with the refrigerant, the refrigerant liquid in the condenser 2 is supplied to the motor 6 and oil cooler 7 via the refrigerant pump 5.
The refrigerant gas is supplied to the evaporator 4 for heat exchange, and the refrigerant gas evaporated by this heat exchange is returned to the evaporator 4. The motor 6 and the oil cooler 7
The amount of refrigerant supplied to the motor 6 is determined by the pressure difference between the condensing pressure and the evaporation pressure, so when the condensing pressure is extremely low, a sufficient amount of refrigerant will not be supplied, so heating and lubrication of the motor 6 will be insufficient. Failures such as increased oil temperature may occur, rendering the system inoperable. Therefore, when the condensation pressure is extremely low, that is, when the cooling fluid temperature is extremely lower than the specified temperature, the refrigerant pump 5 is provided as described above to pump the required amount of refrigerant liquid. .

Further, gas seal pipes 8 and 9 are provided to prevent lubricating oil from leaking from the gear box 10 containing gears and pinions to the refrigerant system such as the motor chamber 11. This gas sealing ability is affected by the amount of supplied gas, that is, the condensing pressure that is the source pressure of the supplied gas, so if the condensing pressure is extremely low, sufficient gas sealing function cannot be obtained, and the lubricating oil will become the refrigerant. There is a risk of inconvenience caused by leakage to the grid.

On the other hand, in conventional air-cooled turbo refrigeration systems, when the outside temperature is low, the number of fans in the air-cooled condenser is controlled to maintain the condensing pressure at a specified value, but this is often wasteful from an energy-saving perspective.

In view of the above-mentioned circumstances, the present invention makes it possible to maintain an appropriate condensing pressure and perform normal and energy-saving refrigeration operation when the cooling fluid temperature of refrigerant gas changes and the condensing pressure changes from a specified value. The purpose of the present invention is to provide a freezing method and a freezing apparatus for carrying out the method.

In order to achieve the above object, the refrigeration method of the present invention detects the liquid level and condensation pressure in the condenser, and when the condensation pressure is lower than a specified value, the condenser is If the automatic valve installed in the condensate outflow pipe is tightened to raise the liquid level of the liquid pool in the condenser, and the condensing pressure is higher than the specified value, the automatic valve installed on the condensate outflow pipe is The valve is released to lower the liquid level in the condenser to the appropriate level, and the effective heat transfer area for condensing the refrigerant gas with the cooling fluid is reduced or increased to bring the condensation pressure to the appropriate value. It is something to control.

In addition, in order to achieve the above object, the refrigeration system of the present invention includes a condenser, an evaporator, and a compressor, and the condenser is provided with a liquid level detector, a condensation pressure detector, and a condensation pressure detector. The condensate outflow pipe of the vessel is equipped with an automatic valve, and is connected to the liquid level detector, the condensing pressure detector, and the automatic valve, and when the condensing pressure is lower than the specified value, the condensing liquid is sent from the condensing pressure detector. Take out the detection signal of the condensation pressure input,
Based on the detection signal, the automatic valve is throttled to raise the liquid level of the liquid pool in the condenser so that the condensing pressure reaches a specified value, and if the condensing pressure is higher than the specified value, the liquid level detector Based on the detection signal, the automatic valve is opened so that the liquid level of the liquid pool in the condenser reaches a specified value, and the liquid level in the condenser is adjusted. A controller is provided to lower the liquid level of the refrigerant and increase or decrease the effective heat transfer area for condensing the refrigerant gas with the cooling liquid.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 shows an example of an apparatus for carrying out the method of the present invention, in which the method is applied to a water-cooled turbo refrigerator.

In the embodiment shown in FIG. 2, an automatic valve 13 is provided in a pipe 12 connecting the condenser 2 and the evaporator 4, which is the condensate outflow pipe of the condenser 2.

Further, a liquid level detector 14 and a condensation pressure detector 15 are attached to the condenser 2, and the liquid level detector 1
4 and the condensing pressure detector 15 are connected to converters 16 and 17 that convert detected values into signals.

Furthermore, a controller 18 is installed, the controller 18
The liquid level detector 1 is connected to the liquid level detector 1 via the converters 16 and 17.
4 and condensing pressure detectors 14 and 15 are connected, and the automatic valve 13 is also connected thereto. The controller 18 receives the liquid level signal in the condenser 2 through the liquid level detector 14 and the converter 16, and receives the condensation pressure signal in the condenser 2 through the condensing pressure detector 15 and the converter 17. If the cooling fluid temperature or condensation pressure of the refrigerant gas is higher than a specified value, a liquid level detection signal is extracted from these signals, and the automatic valve 13 is activated so that the amount of liquid in the condenser 2 becomes the specified value. and when the cooling fluid temperature or condensation pressure of the refrigerant gas is lower than a specified value, a condensation pressure detection signal is taken out and the automatic valve 13 is controlled so that the condensation pressure becomes the specified value. There is.

Next, along with the operation of the refrigeration system of the above embodiment,
Explain the freezing method.

The liquid level in the condenser 2 is detected by the liquid level detector 14, the detected value is converted into a signal by the converter 16 and sent to the controller 18, and the condensing pressure is detected by the condensing pressure detector 15. , the detected value is converted into a signal by a converter 17, which is also sent to a controller 18.

When the cooling fluid temperature of the refrigerant gas is high and the condensing pressure is higher than the specified value, the controller 18 extracts a liquid level detection signal from the liquid level detection signal and the condensing pressure detection signal, Based on the liquid level detection signal, a control signal is sent to the automatic valve 13 so that the amount of liquid in the condenser 2 becomes a specified value. As a result, liquid level control is performed through the automatic valve 13. In other words, the number of immersed heat transfer tubes 2a changes depending on the liquid level of the liquid pool in the condenser 2, which changes the effective heat transfer area for condensation, so that the condensation pressure decreases to a specified value. The liquid level is maintained at the specified value.

Next, when the cooling fluid temperature drops extremely and the condensing pressure drops, the controller 18 sends a control signal to the automatic valve 13 based on the condensing pressure detection signal so that the condensing pressure becomes a specified value. . Thereby, pressure control is performed through the automatic valve 13, and the refrigerant liquid level is raised to an appropriate value so that the condensation pressure becomes a specified value, and is maintained at that liquid level.

As a result of the above control, when the temperature of the cooling fluid is extremely low, the heat transfer tube 2a at the bottom of the condenser 2 is immersed in the refrigerant liquid, and the cooling fluid no longer flows through the immersed heat transfer tube 2a. Since there is no condensation effect, the effective heat transfer area for condensation is reduced.
The condensing pressure can be increased to a specified value, that is, an appropriate value. Also, at this time, the compression head increases because the condensing pressure increases, but the cycle efficiency hardly changes due to the supercooling effect. Therefore, energy-saving refrigeration operation becomes possible.

Note that the other configurations and operations in the embodiment of the present invention shown in FIG. 2 are the same as those described with respect to FIG. 1.

Furthermore, in this embodiment, the pressure reducing device 3 can be removed and the automatic valve 13 can also function as the pressure reducing device.

Next, FIG. 3 shows an embodiment in which the present invention is applied to an air-cooled turbo refrigerator.

This air-cooled turbo refrigerator generally includes an air-cooled condenser 20 as a coil-type condenser (hereinafter referred to as a condenser), a high-pressure receiver 21, and a balance pipe 22. The air-cooled condenser 20
has a heat transfer tube 20a that condenses refrigerant gas and a blower fan 20b.

An automatic valve 13 is installed in the condensate outflow pipe 23 connecting the outlet end of the heat transfer tube 20a and the high pressure receiver 21.
is provided, a liquid level detector 14 is attached between the inlet end and the outlet end of the heat exchanger tube 20a, and the heat exchanger tube 20
It is the same as described for the water-cooled turbo refrigerator shown in FIG. 2 above, except that a condensation pressure detector 15 is attached to the inlet end of
The functions of the automatic valve 13, the liquid level detector 14 and the converter 16, the condensing pressure detector 15 and the converter 17, and the controller 18 are also similar to those explained with reference to FIG. 2 above.

The present invention has the configuration and operation described above,
According to the method of the present invention, when the cooling fluid temperature of the refrigerant gas is low and the condensing pressure is low, the automatic valve is pressure-controlled based on the detected value of the condensing pressure so that the condensing pressure becomes a specified value. , the lower heat transfer tube is immersed in the condensate to prevent condensation, and this allows the condensation pressure to rise to the specified value, so if the cooling fluid temperature drops significantly below the specified temperature. However, it has the effect of enabling normal refrigeration operation, and in this case, since the refrigerant liquid is supercooled, the cycle efficiency hardly changes, so it also has the effect of enabling energy-saving refrigeration operation.

Further, according to the device of the present invention, an automatic valve provided in the condensate outflow pipe, a liquid level detector and a condensing pressure detector installed in the condenser, and receiving detection signals from these and transmitting a control signal to the automatic valve. At least when the cooling body temperature is low and the condensing pressure is low, the pressure is controlled through the automatic valve so that the condensing pressure reaches a specified value by cooperating with the controller that sends the condensing pressure. This has the effect of allowing the freezing method to be carried out appropriately.

[Brief explanation of drawings]

Figure 1 is a system diagram of a conventional water-cooled turbo refrigeration system.
FIG. 2 is a system diagram showing an embodiment of the present invention applied to a water-cooled turbo refrigeration system, which is an apparatus for carrying out the method of the present invention, and FIG. 3 is a system diagram showing an embodiment of the present invention applied to an air-cooled turbo refrigeration system. It is a system diagram showing an example of. 2, 20... Condenser, 12, 23... Condensate outflow pipe, 13... Automatic valve, 14... Liquid level detector,
15... Condensation pressure detector, 16, 17... Converter, 18... Controller.

Claims (1)

[Claims] 1. The liquid level and condensation pressure in the condenser are detected, and if the condensation pressure is lower than a specified value, an automatic control system installed in the condensate outflow piping of the condenser When the valve is tightened to raise the liquid level in the condenser, and the condensing pressure is higher than the specified value, the automatic valve is opened based on the detected liquid level in the condenser. A refrigeration method characterized by lowering the liquid level of a liquid pool to an appropriate position and controlling the condensation pressure to an appropriate value by decreasing or increasing the heat transfer area effective for condensing refrigerant gas with a cooling fluid. . 2. In a refrigeration system consisting of a condenser, an evaporator, and a compressor, the condenser is equipped with a liquid level detector, a condensation pressure detector, and a condensate outflow pipe of the condenser is equipped with an automatic valve, and the liquid level detector is equipped with an automatic valve. a condensation pressure detector, and the automatic valve, and when the condensation pressure is lower than a specified value, extract a detection signal of the condensation pressure sent from the condensation pressure detector, and based on the detection signal, The automatic valve is throttled to raise the liquid level in the condenser so that the condensing pressure reaches the specified value, and when the condensing pressure is higher than the specified value, the liquid sent from the liquid level detector Based on the detection signal, the automatic valve is opened to lower the liquid level of the liquid pool in the condenser so that the liquid level of the liquid pool in the condenser reaches a specified value. ,
A refrigeration device comprising a controller that increases or decreases a heat transfer area effective for condensing refrigerant gas with a cooling liquid.