Chiller Systems: A Primer in Absorption Technology

Chillers are machines that reduce the temperature in a containment area. One technique is using heat to cycle the refrigerant and absorbent for a cooling process called absorption technology. To learn more, keep reading.

How it Works

Absorption technology works by using a thermodynamic cycle driven by heat to evaporate water and produce cool air.

This starts by moving steam, hot liquid, or combusted air into an ammonia or water refrigerant until it boils and evaporates. The result is a low partial pressure (PP) environment which decreases the temperature within an area (usually the compartment of the OEM chiller). A fluid solution (the absorbent) will then absorb the gas - the saturated absorbent flows back into the source of the heat, and the process repeats.

Types

Currently, OEM chiller manufacturers create three types of absorption refrigerators. They are:

Salt and Water System: This is commonly used in large industrial plants because it's simple. For it to work, water is evaporated under low pressure to chill the coils. A solution of lithium bromide and lithium chloride saltwater absorbs the resulting gas and recycles it into the source of the heat.

Water Spray Refrigeration: The process works by first taking in warm, moist air which is then sprayed with a salt solution. Doing so decreases the humidity as it's then moved into an evaporative cooler. Inside, it's re-humidified and cooled with freshwater. After passing through, it's spritzed with salt water again, dehumidify it and making it cold and dry.

The sprayed salt water solution is collected and moved for heating and evaporation. The resulting vapor is recycled by condensation and routing back into the evaporative cooler.

Single Pressure: Chillers using this method balance out the hot and cold components' partial pressure to make the total constant within its system. This is done by taking advantage of the chemical reactions of ammonia, hydrogen gas, and water to create low and high PP. Doing so efficiently utilizes the evaporation and condensation of a liquid solution to create cool air.

Single pressure cycle's start with liquid ammonia (the refrigerant) entering a hot hydrogen gas-filled evaporator. The chemical reaction it creates lowers the PP of that area while also turning the hydrogen and ammonia into vapor. The absorbent fluid collects the heat within these gasses as it flows into the condenser. The cool air is then expelled while the refrigerant-saturated warm water is recycled.

With how it uses heat for cycling the refrigerant and absorbent, absorption technology is efficient in both consuming energy and conserving its materials. As such, coolers using this system are preferred because of their low electricity use. If you're interested in learning more about other methods, you can search online or talk to an OEM chiller manufacturer.