Water sorption property and cooling performance using natural mesoporous siliceous shale impregnated with LiCl for adsorption heat pump. (5th June 2020)

• Record Type: Journal Article
• Authors: Togawa, Junya; Kurokawa, Asami; Nagano, Katsunori
• Is Part Of: Applied thermal engineering. Volume 173(2020)
• Publication Date: 2020-06-05
• Subjects: Adsorption heat pump -- Water sorption -- Wakkanai siliceous shale -- LiCl -- COP -- SCP; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2020.115241
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Adsorption heat pump using composite adsorbent of LiCl-WSS. Threshold limit of water uptake was decided from the water sorption isotherm and pore volume. Safety of threshold limit was confirmed from the elution test. SCP of 498 W/kg and COP of 0.41 were obtained by using 20 wt% LiCl – WSS composite adsorbent. Abstract: The composite adsorbent of natural mesoporous powder of Wakkanai siliceous shale (WSS) impregnated with LiCl has been investigated. In this study, the slurry of WSS–LiCl with acryl resin as a binder was prepared for fabricating an adsorbent-filled heat exchanger (HEX). The optimal LiCl content for the impregnation with WSS was 20 wt%, which was chosen from the relation between water uptake and pore volume. The theoretical sorption amounts were estimated from various sorption isotherms, and the value was 0.34 g/g at the temperature conditions of 80 °C (regeneration), 30 °C (condensation and adsorption), and 15 °C (evaporation). From the analysis of sorption heat, it was found that water adsorption and desorption occurred repeatedly at the lower region of 45–50 kJ/mol at the driving conditions for the adsorption heat pump. To evaluate the coefficient of cooling performance (COP) and a specific cooling power (SCP), the adsorbent-filled HEX was prepared using a small-sized corrugated-fin-type aluminum HEX and the slurry. The COP and SCP were 0.41 and 498 W/kg at 80 °C of regeneration, respectively.