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.
Highlights
The energy consumption of air conditioning accounts for 50% of building consumption and 15% of total electricity consumption, respectively [1,2]
The effect of the generator set point temperature on the performance was stronger for the months with with weak and moderate solar irradiance, i.e., the monthly energy savings of April, May, June, July, weak and moderate solar irradiance, i.e., the monthly energy savings of April, May, June, July, August, August, September, and October rose by 123.7%, 38.7%, 38.2%, 25%, 12.3%, 8.8%, and 10.6%, September, and October rose by 123.7%, 38.7%, 38.2%, 25%, 12.3%, 8.8%, and 10.6%, respectively, when respectively, when the setting temperature of generators went up from 60 °C to the optimal one
It was derived that the coefficient of performance (COP) of compression subsystems enhanced by 14.1% due to the solar cooling compared to its nominal COP
Summary
The energy consumption of air conditioning accounts for 50% of building consumption and 15% of total electricity consumption, respectively [1,2]. The operation of solar power plants becomes more flexible and performance rises remarkably when the collector setting temperature is allowed to change during the working period [20]. In addition to the solar heating and the power plant, the impact of collector setting temperature on performance of solar thermal cooling facilities has been researched as well. Qu [21] performed the comparison of solar LiBr/H2 O double effect absorption chillers with constant and variable hot water flow rates and concluded that systems with variable hot water flow rates extend the working period by. It was shown that the strategy in which the collector setting temperature was adjusted in terms of the cooling load enhanced the solar fraction by 11% compared to the constant hot water flow rate strategy [25]. The paper is helpful for the improvement of SASCHCS operation
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call