TABLE OF CONTENTS This chapter surveys and summarizes the types of absorption equipment that are currently manufactured and/or commonly encountered. The equipment can be broadly categorized by whether it uses water or ammonia as refrigerant. The primary products in the water refrigerant category are large commercial chillers, which use lithium bromide (LiBr) as absorbent. There are three primary products in the ammonia refrigerant category: (1) domestic refrigerators, (2) residential chillers, and (3) large industrial refrigeration units.
This chapter focuses on hardware (i.e., cycle implementation), not on cycle thermodynamics. Cycle thermodynamic descriptions and calculation procedures, along with a tabulation of the types of absorption working pairs and a glossary, are presented in Chapter 1 of the 2005 ASHRAE Handbook Fundamentals.
Absorption units provide two major advantages: (1) they are activated by heat, and (2) no mechanical vapor compression is required. They also do not use atmosphere-harming halogenated refrigerants, and reduce summer electric peak demand. No lubricants, which are known to degrade heat and mass transfer, are required. The various equipment can be direct-fired by combustion of fuel, directly heated by various waste fluids, or heated by steam or hot water (from either direct combustion or from hot waste fluids). Figure 1 illustrates the similarities between absorption and vapor compression systems.
With...
