Efficiency analysis of semi-open sorption heat pump systems. (September 2017)

• Record Type: Journal Article
• Authors: Gluesenkamp, Kyle R.; Chugh, Devesh; Abdelaziz, Omar; Moghaddam, Saeed
• Is Part Of: Renewable energy. Volume 110(2017)
• Page Start: 95
• Page End: 104
• Publication Date: 2017-09
• Subjects: Sorption -- Absorption -- Semi-open -- Efficiency -- Novel cycle; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2016.07.075
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Sorption systems traditionally fall into two categories: closed (for chilling and heat pumping) and open (for dehumidification). Recent work has explored the possibility of semi-open systems, which can perform heat pumping or chilling while utilizing ambient humidity as the working fluid of the cycle, and are capable of being driven by solar, waste, or combustion heat sources. The efficiencies of closed and open systems are well characterized and can be accurately determined from four temperatures (one for each of the main components—desorber, absorber, condenser and evaporator). In this work, the performance potential of semi-open systems is explored by adapting expressions for the efficiency of closed and open systems to the novel semi-open systems. A key new parameter is introduced, which involves both the ambient dry bulb and ambient dew point temperature, since both are critical to semi-open absorber operation. The dew point temperature is necessary to capture the absorption performance, while the dry bulb temperature is needed to calculate sensible heat transfer with surrounding air. Highlights: The performance of a novel thermally-driven semi-open sorption cycle is contrasted with conventional absorption cycle performance. Unlike conventional systems, the semi-open cycle performance depends on ambient dry bulb and dewpoint temperatures. Under most conditions, semi-open cycle COP is slightly lower (1.3–1.5) than conventional (1.5–1.7). The semi-open system is capable of operation to very low dewpoint and dry bulb temperatures, though its performance suffers if both are low. Semi-open cycle performance under low ambient temperature can be improved with higher permeability, lower thermal conductivity membranes.