Chillers. Types, advantages and features in use

Chillers are devices that cool liquid (water, glycol concentrate – non-freezing liquid). They are an integral part of ensuring the comfort of large commercial buildings in the warm season. Also, no cooling process is complete without chillers in many areas of industry. Their power varies from 5 kW to several MW. For clarity, a chiller can be compared to an external unit of an air conditioner, to which a large number of internal units – fan coils – are connected. Therefore, such a system is called a «chiller-fan coil». The principle of operation of the chiller is that any types of fan coils and their combinations can be connected to it.

The main components of the chiller:

1. Compressor
2. Capacitor
3. Evaporator
4. Heat exchanger

The work of these elements is consistent and systematic.
The compressor compresses the freon, increasing its pressure so much that it turns into a liquid state. At the same time, its temperature rises significantly.
When entering the condenser, freon gives off heat to air or water. And, cooling, passes into the evaporator.
A control valve is installed in front of the evaporator, which controls the amount of refrigerant. Freon expands and turns into a gaseous state. At the same time, its temperature drops.

In this state, it passes into the heat exchanger, where it cools the water in the main line.
Cold water entering the fan coils ensures their operation.

According to the type of condenser cooling, chillers are divided into two types:

«air-water»
«water-water»
At the same time, «air-water» is divided into categories according to structural features:

• monobloc for external installation;
• monoblock for internal installation (with centrifugal fans);
• with remote capacitors (split design).

Air chillers use ambient air as a cooling source for the condenser and use fans to force large amounts of air through this heat exchanger.

In water chillers, the water that cools the condenser is directed to a cooling tower, which can be open, closed, or with irrigation.
The evaporative condenser is an alternative to water and air condensers. Maximizing heat removal in evaporative condensers is achieved by continuously circulating water to ensure continuous wetting of the condenser tubes, while fans draw air above them, which evaporates the water and effectively removes the heat to the atmosphere.

Different types of compressors are used in chillers:

• spiral;
• screw;
• centrifugal

Also, in isolated cases, absorption chillers (ABHM) are used, which allow cooling the liquid using excessive secondary heat at industrial enterprises.

All the described types of chillers have their own features, advantages and disadvantages, so the best solution for choosing a chiller will be to contact professionals who will help you understand the huge range of equipment.