3-7.Chilled water cooling

Cooling things with water has been practiced since ancient times.

With direct cooling of cooling watermelon with well water,
There is indirect cooling that water is injected and cooled by heat of vaporization.
We use both for fire fighting.

Such paintings were left in ancient Egyptian ruins. This is a cooler that uses the heat of vaporization of water that evaporates from the unglazed bottle. The water in the bottle becomes cold, and the surrounding air is cooled by the heat of vaporization. The servant fanning behind the jar would be hot, but the Pharaoh could drink cold water and feel cool.

In modern times, indirect cooling, in which water or oil is cooled with water, is the mainstream.
Indirect cooling keeps the primary side clean, reducing environmental impact.
The secondary side is recycled and reused.
Thermal and nuclear power plants use indirect cooling with seawater or river water.

In machining, the cutting oil has lubrication and cooling effects, but well water, tap water, and chillers are used to cool the cutting oil. The “Chiller” is also called “chiller unit”, “water chiller” or “chilling unit”, and is a device that creates a cold water of 5-10℃ with a set of a vapor compression device and operation equipment integrated into one stand.

Cooling towers installed on the roofs of buildings are used to cool the cooling water of refrigerators, which are building air conditioners and district cooling and heating equipment. The temperature of the cooling water of the refrigerator rises when it is used. The cooling water, whose temperature has risen, comes into contact with the outside air that has been forcibly sent by the blower in the cooling tower, and the temperature drops, and is sent back to the refrigerator. Cooling water is efficiently circulated using cooling towers. (Source: Japan Cooling Tower Association)

Mist cooling, which has recently appeared, is an air-conditioning system that sprays water in the form of fine mist and cools and cools by absorbing heat of vaporization when water evaporates. The spray mist has a small particle size and evaporates quickly, realizing a dry cooling environment. Suitable for outdoor, semi-outdoor and indoor with wide open area.

For control using water, a pump is required to send water.
A pressure gauge is required to measure the pump pressure.
There are two ways to adjust the pump pressure: a method of adjusting the number of revolutions with an inverter (the current mainstream because it is ECO) and a method of adjusting the pressure with a pressure control valve.

Temperature is controlled by adjusting the flow rate of water, but a flow control valve is required for that.