Study of the new composite adsorbent of salt LiCl/silica gel–methanol used in an innovative adsorption cooling machine driven by low temperature heat source

Abstract

An adsorption cooling machine with LiCl/Silica gel–methanol was designed and tested, which can work for air conditioning and cold storage. The machine can be driven by low temperature heat source, such as solar energy and industrial waste heat. The composite adsorbent of LiCl/Silica gel has higher adsorption capacity and the methanol has a higher working pressure. So, the cooling performance, system's reliability and the adsorbent's mass transfer performance can be improved. The adsorption machine was experimentally investigated. The test results show that the cycle time and heat recovery process has more influence on COP (Coefficient of Performance) than on cooling capacity. The mass recovery process has significant influence both on cooling capacity and COP. When the cycle time is prolonged from 460 s to 760 s, the cooling capacity and COP increased by 4.3% and 20.6%, respectively. When the hot water inlet temperature, cooling water inlet temperature, cooling medium outlet temperature and heat recovery time are 75 °C, 31 °C, 5 °C and 60 s, respectively, the cooling capacity is improved by 6.3% by heat recovery process while the COP is improved by 27.3%. When the mass recovery time extends from 50 s to 120 s, the cooling capacity and COP increase by 68.4% and 53.3%. When the hot water inlet temperature is about 88 °C, the cooling water inlet temperature is about 25 °C, the adsorption machine produced -4 °C of cooling medium, the cooling capacity and COP were about 1.0 kW and 0.13, respectively.