What is a Chiller?

A chiller is a device that uses a thermodynamic cycle (either compression, absorption, or steam cycle) to extract heat from a refrigerant or specific fluid. This fluid circulates within a heat exchanger to cool water for use in various cooling systems. Essentially, a chiller works by extracting heat from the surrounding environment and transferring it to another medium. It can be considered as an energy pump where the output is cold water used for cooling residential units, commercial buildings, and industrial processes. Chillers are also used for cooling machinery and processes in production lines.

Applications of Chillers

If you’re considering purchasing a chiller, it is important to note that chillers are crucial cooling equipment used for generating cold in industrial factories and buildings. The cold water produced by chillers can be used with air handling units (AHUs) or fan coils to cool indoor spaces or in industrial settings for various cooling processes. Chillers are divided into two main categories based on their application: industrial cooling and air conditioning.

Additionally, absorption chillers can efficiently produce hot water for various heating applications, functioning like a boiler to provide hot water when needed. In compression chillers, the cooling cycle can be reversed (using a heat pump) to generate hot water as well.

Chillers for Air Conditioning

Chillers serve as effective water-based air conditioning systems. Cold water from the chiller circulates through air handling units, fan coils, or cooling coils to cool indoor air. This chilled water absorbs heat from the space, increasing its temperature. Once it reaches a standard temperature (around 7°C), it is returned to the chiller for cooling.

The air cooled by chillers is generally more comfortable than that from evaporative coolers or air conditioners. Unlike swamp coolers, the air from a chiller doesn’t have excess moisture, and unlike air conditioners, it doesn’t produce dry air. This feature is particularly beneficial in dry climates, where the air tends to be too dry.

Chillers and Fan Coils

A common use of chilled water is in conjunction with fan coils (or terminal units). A fan coil unit includes a heat exchanger and a fan that circulates air over the cooling or heating coils. Using chilled water, fan coils provide cooling, and with warm water from a boiler or heating system, they can supply heating. Fan coils allow independent temperature control in each space, making them ideal for offices, residential buildings, and commercial complexes.

Chillers and Air Coolers

Air coolers (also called evaporative coolers) are similar to air-cooled evaporators, commonly used in cold storage areas. However, instead of refrigerants, they use hot or cold water circulating through coils. Air coolers are typically used in large industrial production halls and warehouses where fresh air isn’t needed as much, and the space is not suited for ducts and air distribution. In these settings, air coolers may be used alone or alongside air handling units.

Chillers in Industrial Cooling

Cold water produced by chillers is extensively used in industrial cooling processes. This includes cooling machinery and systems on production lines in industries such as metalworking, foundries, plastics, welding, pharmaceuticals, healthcare, petrochemicals, oil, food production, paper and cement manufacturing, fish farming, and road construction.

While chillers are primarily used for generating cold water, they must operate within a specific temperature range. If the water temperature exceeds the ambient wet-bulb temperature, cooling towers are used. Similarly, if the temperature exceeds the dry-bulb temperature, evaporative coolers are required to reduce the water temperature. Chillers are typically used for cooling water between -40°C to 3°C above the wet-bulb temperature. Specific compressors are designed for this range.