Cooling method and cooling system for electronic device

Abstract

A cooling method for an electronic device, comprising:naturally circulating a refrigerant between: an evaporator which vaporizes the refrigerant by heat exchange with exhaust hot air from the electronic device, and cools the exhaust hot air; and one of a cooling tower and a condenser which is placed at a position higher than the evaporator, and liquefies the vaporized refrigerant; andvalve-controlling a flow rate of a refrigerant liquid to be supplied to the evaporator so that an air temperature after heat has been exchanged for cooling by the evaporator becomes a temperature suited to an operating environment of the electronic device, whereinone of a condensation temperature and a condensation pressure of a refrigerant gas in one of the cooling tower and the condenser do not fluctuate even when the flow rate of the refrigerant liquid to be supplied to the evaporator is valve-controlled.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a cooling method and a cooling system for an electronic device, and more particularly, to a cooling method and a cooling system for an electronic device which are used for locally cooling electronic devices such as a computer and a server placed in a server room by naturally circulating a refrigerant between an evaporator and a cooling tower (or a condenser).[0003]2. Description of the Related Art[0004]In a server room, a large number of electronic devices such as a computer and a server are installed in an intensive state. The electronic devices are installed generally in a rack mount system, that is, in a system in which the electronic devices are divided on a functional unit basis to be housed in a rack (casing) and such racks are stacked on top of one another in a cabinet. Then, a large number of such cabinets are arranged in a line on a floor of the server room.[0005]These electroni...

AI Technical Summary

Benefits of technology

[0017]According to the first aspect of the present invention, even when the flow rate of the refrigerant liquid to be supplied to the evaporator is valve-controlled, one of the condensation temperature and the condensation pressure of the refrigerant gas in one of the cooling tower and the condenser corresponding to the low pressure side of the cooling system is controlled so as not to fluctuate. In this way, in parallel with the valve control of the evaporator, one of the condensation temperature and the condensation pressure in one of the cooling tower and the condenser is controlled so as not to fluctuate, whereby the fluctuations in evaporation pressure of the evaporator can be suppressed. As a result, it is possible to stably maintain the natural circulation of the refrigerant and to prevent dew condensation from being caused on a surface of the evaporator.

[0075]As described above, according to the cooling method and the cooling system for the electronic device of the present invention, it is possible to stably maintain the natural circulation of the refrigerant and to prevent dew condensation from being caused on the surface of the evaporator, even when the flow rate of the refrigerant of the evaporator is valve-controlled in the cooling system having the refrigerant natural circulation system.

Problems solved by technology

These electronic devices require a given temperature environment for a normal operation thereof, and if a high temperature state occurs, a trouble such as a system halt may be caused.

However, in recent years, along with a rapid increase in processing speed and processing ability of the electronic devices, an amount of head generated from the electronic devices steadily continues to increase, and the running cost of the air-conditioning equipment is also significantly increasing.

In addition, a method of cooling a server room by floor blow-out air conditioning using package air-conditioning equipment has been also adopted, but in order to suppress a local increase in temperature due to exhaust heat from the electronic device, it is necessary to air-condition the entire server room, which thus leads to a problem that the cooling efficiency is low.

Therefore, the refrigerant natural circulation system in which an operation state of the cooling system is significantly affected by the pipe resistance has a problem that the valve control may cause fluctuations in evaporation temperature.

For example, an evaporation pressure inside of the evaporator is decreased by the valve control, and accordingly a decrease in evaporation temperature more than necessary is caused, so that a considerable decrease in temperature at an exit of the evaporator may occur.

There is fear that this considerable decrease in temperature at the exit of the evaporator causes dew condensation on a surface of the evaporator.

If dew condensation is caused on the surface of the evaporator, there arise not only a problem that dew condensation water adversely affects the electronic device and accordingly the reliability is deteriorated but also a problem that an energy loss for preventing dew condensation occurs.

Accordingly, if the evaporation temperature fluctuates, the evaporation pressure also fluctuates, which thus leads to a problem that the natural circulation of the refrigerant becomes unstable.

Images