Solar heating and cooling with absorption chiller and latent heat storage

Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458]Performance figures and control strategies of an innovative solar heating and cooling system (SHC-System) composed of an aqueous lithium bromide-water single-effect absorption chiller with 10 kW cooling capacity, a dry heat rejection system and a low phase change temperature (28-29°C) latent heat storage based on salt hydrates are given. During cooling season the latent heat storage serves as a secondary heat sink supporting the dry air cooler at high ambient temperatures to ensure 32°C coolant to the absorption chiller at any time. In the heating season the latent heat storage buffers heat surplus of the solar collectors latently by melting the phase change material (PCM) calcium chloride hexahydrate. As a result of the constant temperature during charging, solar thermal collector efficiency is increased and furthermore the overall heat dissipation is reduced. The results on the one hand show a positive effect on the cooling capacity, electrical and thermal Coefficient of Performance (COP) of the absorption chiller, which are significantly increased especially at hot days compared to solely dry air cooled systems. On the other hand a high solar fraction in the heating period, due to constantly low storage temperatures, is achieved