JP3352400B2 - Indirect outside air cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system for a high heat generating device which needs to be cooled even when the outside air temperature is low. The present invention relates to an indirect outside air cooling device that performs cooling.

[0002]

2. Description of the Related Art In general, as an indoor cooling method, there is an air conditioner using a compression refrigeration cycle. The cooling principle of this air conditioner will be described below. The gas refrigerant is pressurized by the compressor and sent to the condenser as a high-temperature and high-pressure gas, where the refrigerant exchanges heat with outside air to liquefy the refrigerant. The liquid refrigerant is decompressed by the expansion valve, reaches the evaporator, cools the indoor air in the evaporator, gasifies the refrigerant, and returns to the compressor. Thereafter, by repeating this cycle, indoor heat is released by releasing indoor heat to the atmosphere via an evaporator and a condenser.

[0003] This description is an example of a case where the outside air temperature is high. However, when the outside air temperature is low, a cooling pump is provided in place of the compressor, and the cooling pump is operated only by operating the refrigerant pump to circulate the refrigerant. Can be performed. This method is called indirect outside air cooling because the refrigerant is once cooled by outside air and the room is cooled by the cooled refrigerant. Although water may be used as a circulating medium, a phase change can be used by using a refrigerant, and pump power can be reduced by reducing the amount of circulation.

[0004] A cooling cycle in the indirect outside air cooling will be described below. The gas refrigerant that has exited the evaporator is sent to the condenser as it is, cooled and liquefied by low-temperature outside air in the condenser, and sent to the refrigerant pump. The liquid refrigerant is pressurized by the refrigerant pump and guided to the evaporator. In the evaporator, the refrigerant is gasified by cooling the indoor air, and returns to the condenser again. Hereinafter, this cycle is repeated, and indoor heat is released by releasing indoor heat to the atmosphere via an evaporator and a condenser.

[0005]

In the indirect outside air cooling system as described above, as the outside air temperature decreases during operation,
The refrigerant pressure of the outdoor heat exchanger (condenser) decreases, and accordingly, the refrigerant pressure of the indoor heat exchanger (evaporator) also decreases.

If the refrigerant pressure in the indoor heat exchanger is excessively reduced, the amount of condensation in the indoor heat exchanger increases and the indoor humidity decreases, or the surface of the indoor heat exchanger becomes frosted and the indoor heat exchanger becomes frosted. A problem arises in that the amount of air passing through the air decreases and the cooling capacity decreases.

[0007] The present invention has been made in view of the above circumstances,
Its purpose is to prevent a situation in which the refrigerant pressure in the indoor heat exchanger is excessively reduced, thereby avoiding a decrease in indoor humidity and a decrease in cooling capacity. An object of the present invention is to provide a cooling device.

[0008]

The indirect outdoor air cooling apparatus according to the present invention comprises a cycle in which a refrigerant pump, an indoor heat exchanger, and an outdoor heat exchanger are connected and the refrigerant is circulated by operating the refrigerant pump . And in an indirect outside air cooling device that includes an indoor-side blower and an outdoor-side blower and performs cooling using low-temperature outside air in winter or the like, a pressure detection unit that detects a pressure of a refrigerant in an indoor heat exchanger, When the detection pressure of the pressure detection means falls below the pressure lower limit set value, the wind of the outdoor blower is reduced.
When the detected pressure exceeds the pressure lower limit set value,
Control means for increasing the air volume of the outdoor blower to the original state ;
Is provided.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a refrigerant pump 1, an evaporator (indoor heat exchanger) 2, and a condenser (outdoor heat exchanger) 3 are sequentially connected by piping. An indoor blower 4 is provided for the evaporator 2, and an outdoor blower 5 is provided for the condenser 3.

A pressure sensor 10 is attached to a pipe near the evaporator 2 as pressure detecting means. Refrigerant pump 1
Is driven by the refrigerant pump inverter 11. The refrigerant pump inverter 11 rectifies the voltage of the commercial AC power supply, converts the rectified voltage into AC having a frequency corresponding to a command from a controller 20 described later, and outputs the AC. This output is supplied to the refrigerant pump 1 as drive power.

The indoor blower 4 is driven and blown by a blower drive circuit 12. The outdoor blower 5
Drive and air volume are controlled by the blower drive circuit 13. Reference numeral 20 denotes a controller for controlling the entire apparatus. The controller 20 is connected to the refrigerant pump inverter 11, the blower drive circuit 12, the blower drive circuit 13, and the pressure sensor 10.

The controller 20 has, as main functional means, control means for controlling the air volume of the outdoor blower 5 so that the pressure detected by the pressure sensor 10 does not become lower than a set value. Next, the operation of the above configuration will be described.

First, the principle of cooling will be described.
The gas refrigerant leaving the evaporator 2 is sent to the condenser 3 as it is,
Cooled by the low-temperature outside air in the condenser 3 and liquefied, the refrigerant pump 1
Sent to The liquid refrigerant is pressurized by the refrigerant pump 1 and guided to the evaporator 2. In the evaporator 2, the refrigerant is gasified by cooling the indoor air, and returns to the condenser 3 again. Hereinafter, this cycle is repeated, and indoor heat is released by releasing indoor heat to the atmosphere via the evaporator 2 and the condenser 3.

This device is a cooling device intended for a room that generates a large amount of heat in a room and needs cooling in winter. The purpose of this device is to keep the room temperature at a constant set value, as in a general air conditioner.

However, as the outside air temperature decreases, the refrigerant pressure in the condenser 3 decreases, and the refrigerant pressure in the evaporator 2 also decreases. If the refrigerant pressure in the evaporator 2 is excessively reduced, there is a problem that frost is formed on the surface of the evaporator 2 and the air passage is blocked.

Therefore, as shown in the flowchart of FIG. 2, the detected pressure of the pressure sensor 10 is compared with a predetermined pressure lower limit set value. When the detected pressure falls below the pressure lower limit set value, the air volume of the outdoor blower 5 is reduced.

When the air volume of the outdoor blower 5 decreases, the external heat transfer coefficient of the condenser (outdoor heat exchanger) 3 decreases, and the condenser 3
Refrigerant pressure rises. Accordingly, the refrigerant pressure of the evaporator (indoor heat exchanger) 2 increases.

When the detected pressure is equal to or higher than the lower pressure set value,
The air volume of the outdoor blower 5 is increased to the original state. The heat transfer coefficient outside the tube of the condenser 3 is improved, and the refrigerant pressure of the condenser 3 is reduced. Thus, by controlling the air volume of the outdoor blower 5 so that the refrigerant pressure of the evaporator 2 does not become lower than the pressure lower limit set value, it is possible to prevent the refrigerant pressure of the evaporator 2 from excessively decreasing.

Therefore, it is possible to avoid an increase in the amount of condensation in the evaporator 2 and a decrease in the indoor humidity accompanying the increase. Furthermore, it is possible to prevent frost from adhering to the surface of the evaporator 2 and to reduce the amount of air flow therewith, thereby preventing a decrease in cooling capacity.

That is, the problem associated with the pressure drop of the indoor heat exchanger in the heat transfer system is eliminated, and the cooling operation using the low-temperature outside air can be performed in the room accommodating the high heat-generating equipment. Power consumption can be reduced as compared with a cooling device using an air conditioner. The present invention is not limited to the above embodiment, and various modifications can be made without changing the gist.

[0021]

As described above, according to the present invention, the cooling
In the cycle where refrigerant is circulated by operating the medium pump
The refrigerant pressure in the indoor heat exchanger
If it is lower than, the air volume of the outdoor blower is reduced and the pressure lower limit is set.
When the air pressure exceeds the value, the air volume of the outdoor blower is increased to the original state, so that it is possible to prevent a situation in which the refrigerant pressure of the indoor heat exchanger is excessively reduced. It is possible to provide a highly reliable indirect outside air cooling device capable of avoiding a decrease in cooling capacity.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of one embodiment.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 refrigerant pump 2 evaporator (indoor heat exchanger) 3 condenser (outdoor heat exchanger) 4 indoor blower 5 outdoor blower 10 pressure sensor (pressure detection means) 11 refrigerant pump inverter 12 , 13 ... Blower drive circuit 20 ... Controller

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahide Yanagi 3-4-1 Shibaura, Minato-ku, Tokyo Inside NTT Facilities Co., Ltd. (72) Inventor Akira Sasaki 3-chome Nishishinjuku, Shinjuku-ku, Tokyo 19-2 Nippon Telegraph and Telephone Corporation (56) References JP-A-9-61076 (JP, A) JP-A-4-98040 (JP, A) JP-A-4-327747 (JP, A) JP-A-2-150650 (JP, A) JP-A-9-68255 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F24F 11/02 102

Claims (1)

(57) [Claims] 1. A refrigerant pump, an indoor heat exchanger, and an outdoor heat exchanger are connected to each other to provide a cycle for circulating a refrigerant by operating the refrigerant pump , and an indoor blower and an outdoor blower are provided, and low-temperature outside air is supplied in winter and the like. In the indirect outside air cooling device that performs cooling using a pressure detection unit that detects a pressure of a refrigerant in the indoor heat exchanger, a detection pressure of the pressure detection unit is lower than a pressure lower limit set value.
And the air volume of the outdoor blower is reduced, and the detected pressure is
When the lower limit value is exceeded, the air volume of the outdoor blower is reduced to the original value.
Control means for increasing the state of the indirect outside air cooling device.