Exergoeconomic design criterion of solar absorption-subcooled compression hybrid cooling system based on the variable working conditions

• Published in: Energy conversion and management 2019-01, Vol.180, p.889-903
• Main Authors: Jing, Yue, Li, Zeyu, Chen, Hongkai, Lu, Shengzi, Lv, Shiliang
• Format: Article
• Language: English
• Subjects: Absorption; Absorption chiller; Compression; Cooling; Cooling loads; Cooling systems; Cooling water; Cost analysis; Design; Design criteria; Design engineering; Evaporators; Exergoeconomics; Flow rates; Flow velocity; High rise buildings; Hot water; Hybrid system; Hybrid systems; Irradiance; Low rise buildings; Off-design condition; Solar cooling; Subsystems; Water temperature; Working conditions
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2018.11.004

•Exergoeconomic off-design model is built and the maximum deviation is less than 9%•Design of system in low-rise building relies on working condition strongly.•Component with large size is attractive for system in high-rise building.•Design for different decision variables is usually different for low-rise building.•Design for different decision variables is usually similar for high-rise building. The solar absorption-subcooled compression hybrid cooling system (SASCHCS) is subjected to the off-design operation due to the variation of solar irradiance and cooling load. Therefore, the recent design based on the specific condition is difficult to make the system cost-effective in the entire working range. This paper mainly deals with the exergoeconomic design criterion of hybrid system based on the variable working conditions to access the trade-off of investment cost and performance in the whole working condition. The SASCHCS employed in the low-rise building and the high-rise building is considered. Besides, twenty-four cases with different important parameters, i.e., the size of absorption subsystem, condenser and evaporator of compression subsystem as well as isentropic efficiency of compressor, are analyzed in detail. The product cost flow rate and relative cost difference are taken as the decision variables. The exergoeconomic off-design model is developed at first. Subsequently, the decision variables for different temperatures of hot water and cooling water as well as load level is obtained and analyzed. It is found that the difference of the design guideline for the system used in the low-rise building and high-rise building lies in the size of absorption subsystem and condenser, i.e., the lowest scale of absorption chiller is appropriate when the temperature of hot water is less than 75 °C for the facility applied in the low-rise building, but the largest size of absorption subsystem is attractive in the entire range of hot water temperature as the hybrid system is used in the high-rise building. This paper is positive for the development of design theory and helpful to design the cost-effective SASCHCS under the entire working range.