Compressor-Aid Absorption Chiller Working on Low Grade Temperature Heat Source: A Thermodynamic Analysis

Abstract

Searching for new technology to exploit the wasted heat is continuing. Using absorption chillers is a promising technology. Single-effect LiBr-H2O absorption chillers represent the simplest type. These chillers have low efficiency and use high operation temperatures. In this study, a new modification is suggested to improve the efficiency and lower the generator (inlet) temperature, so the developed machine can use the wasted heat to generate a cooling load. The suggested modification concludes by inserting a small compressor between the generator and the condenser, so that, the pressure will be reduced in the generator which reduces the temperature while increasing the condenser pressure will lead to increase the vapor condensation (increasing the chiller performance). The results of the modified model of the device showed that the operating temperature could be reduced from 100℃ to 90℃ while the performance increased from 0.721 to 0.803. Moreover, the cooling capacity could be increased from 10.575 kW to 15.278 kW. These results promote the possibility to operate the suggested form of absorption chillers with low-grade temperature heat sources such as solar energy or wasted heat from industries.