A Hybrid Solar Absorption Cooling System for Heat Recovery in Data Centers

With the increasing demand for energy saving in the data center, heat recovery in data centers has received wide attention because of its characteristics of energy consumption reduction and economic benefits. In this study, a hybrid solar absorption cooling system is proposed for data centers to improve waste heat utilization in different seasons and reduce system energy consumption. The waste heat from the water-cooled racks is used for district heating and cooling production. Solar thermal collectors are installed to improve the quality of the waste heat. In addition, natural cooling is preferentially used in winter to reduce system energy consumption. The system performance is simulated in a data center in Tianjin. The results show that 40.2% of the waste heat from the water-cooled racks can be used in district heating. With the limitation of the roof area and the intermittency of the solar, only 5.7% of the cooling demand of the air-cooled racks can be met by the absorption chiller. If the absorption chiller operates continuously at higher a hot water temperature, the waste heat utilization ratio can be increased to 36% and energy saving can be achieved by 24%. As a result, the economic performance becomes more promising and the payback period will be reduced to 8 years. This study can provide theoretical support for heat recovery in data centers.