These chillers are available from 50 tons-1,500 tons. Absorption chillers use heat to drive the refrigeration cycle. They produce chilled water while consuming just a small amount of electricity to run the pumps on the unit. Absorption chillers generally use steam or hot water to drive the lithium bromide refrigeration cycle but can also use other heat sources. The generator section is heated with low pressure steam, high temperature hot water, or other liquids (some types of generators use high pressure steam). The most common type of absorption chillers are indirect fire lithium bromide/water cycle. Small direct gas fire units are available from 3.5 tons to 25 tons.
These chillers are suitable for constant load without high load change (i.e. hospitals). Absorption Chillers do not work with VFDs and require high maintenance (if they are not used for 2 to 3 months, the liquid must be changed).
There are different types of absorption chillers such as Direct-Fired and Absorption Liquid (Single Stage & Two Stage).
Direct-fired absorption chillers: Can be used as a primary component for hybrid plants or other applications where electrical demand and consumption are expensive or in short supply. The chiller uses natural gas or other fuels to fire the absorption refrigeration cycle.
Liquid chillers: Are either Single Stage or Two Stage. Single-stage absorption chiller uses low pressure steam or low grade hot water to drive the absorption cycle. This absorption chiller is particularly useful for energy conserving applications such as heat recovery or process applications where a low cost heat source is available.
Two-stage chillers use the efficient series solution flow cycle, which improves the unit efficiency over 50% when compared to single effect models. These two-stage chillers are ideal when medium pressure steam or 350°F (176.7°C) hot water is available.