New HVAC Technologies – Solar Absorption Refrigeration

Thread Content

A schematic diagram of a solar absorption refrigeration system is shown below. Its characteristics are related to the refrigerant used in the system; the refrigerants commonly used in absorption refrigeration systems fall into four main categories: water, ammonia, ethanol, and Freon. Among these, using water as a refrigerant is one of the most actively researched topics at present. Research on this topic focuses on overcoming the drawbacks of commercially available lithium bromide absorption chillers that are mass-produced today, such as their tendency to crystallize, high corrosivity, and the requirement that their evaporation temperature be above 0°C ； Research on ammonia focuses mainly on its various drawbacks, such as: a lower coefficient of performance for cooling compared to lithium bromide, high operating pressures, certain levels of danger, toxicity, and a not sufficiently large difference in boiling points between ammonia and water, which requires distillation. Although absorption refrigeration is a relatively mature technology, its system costs are higher than those of vapor compression refrigeration, and it is mainly used in large-scale central air conditioning systems.