**E**ff**ect of Hot Water Setting Temperature on Performance of Solar Absorption-Subcooled Compression Hybrid Cooling Systems**

#### **Jinfang Zhang 1,2,3, Zeyu Li 1,2,3,\*, Hongkai Chen 1,2,3 and Yongrui Xu 1,2,3**


Received: 6 October 2019; Accepted: 25 December 2019; Published: 29 December 2019

**Abstract:** The solar absorption-subcooled compression hybrid cooling system (SASCHCS) displays outstanding advantages in high-rise buildings. Since the performance coupling of collectors and absorption subsystems is stronger due to the absence of backup heat and the effect of generator setting temperature has not been realized adequately, it is highly important to study the relationship of SASCHCS operation and the set point temperature of hot water to prevent performance deterioration by inappropriate settings. Therefore, the paper mainly deals with the effect of collector and generator setting temperature. The investigation was based on the entire cooling period of a typical high-rise office building in subtropical Guangzhou. The off-design model of hybrid systems was built at first. Subsequently, the impact mechanism of setting temperature in two hot water cycles on facility operation was analyzed. It was found that the excessive rise of collector setting temperature deteriorated the energy saving, while the appropriate improvement of generator set point temperature was beneficial for the solar cooling. Besides, global optimization by the genetic algorithm displayed that 71.6 ◦C for the collector setting temperature with 64.5 ◦C for the generator was optimal for annual operation. The paper is helpful in enhancing the operation performance of SASCHCS.

**Keywords:** setting temperature of hot water; solar cooling; absorption chiller; subcooled compression; hybrid system
