Operating characteristics of an adsorption chiller with heat and mass recovery scheme for low-grade heat source

Abstract

Waste heat recovery from data center is regarded as one of the most promising application of adsorption refrigeration in the future. To better understanding of the system, the operating characteristics, including temperature, pressure and heat exchange capacity, of the adsorption chiller for such low-grade heat source should be revealed. Unfortunately, they have not been detailedly reported yet. In this paper, lab experiments on a silica gel-water adsorption chiller prototype with heat and mass recovery scheme are implemented. The results show that this chiller can achieve 3.17 kW of average cooling power and 0.482 of coefficient of performance under the conditions of 60 °C hot water inlet temperature, 30 °C cooling water inlet temperature and 22 °C chilled water inlet temperature. The temperature and pressure characteristics reveal that adsorbent bed desorption phase results in the worsening of the deviation from ideal cycle when compared to its adsorption phase. Hence, the heat and mass transfer performance of bed in desorption phase is prioritized to be enhanced. The analysis on heat exchange capacity indicates that mass recovery operation is more beneficial to the adsorption reaction. The optimal heat recovery time is found to be 24 s while the heat recovery efficiency is 0.711.