Experimental study of an adsorption heat storage systems for building applications

In this paper an Adsorption Heat Storage System (AdHS-HFC134a)/heating system utilising Vermiculite and Calcium Chloride composite adsorbent material was experimentally investigated. The main aim of the experimental investigations is to carry out preliminary tests on a small scale Adsorption Heat Storage Systems (AdHS-HFC134a) using a heat pump circuit as the regeneration heat source. The test rig was constructed using Vertical Glass Pipes with a heat pump circuit using a miniature compressor for transporting the refrigeration gas as a heat source for desorption cycle. The system also incorporates condenser coils, evaporator coils, and an expansion valve. The integration with a heat pump circuit is to analyse the performance of an AdHS-HFC134a using off peak power in desorption/charging cycle and utilising renewable energy sources to minimise energy demands from fossil fuels. The refrigerant gas used for the regeneration cycle is HFC R134a due to its low global warming potential (GWP), and no Ozone Depletion Potential (ODP), adopted for the proposed systems. Firstly, the regeneration phase occurs during night hours, when cheap off peak electricity is available under the ‘Economy 7’ tariff that is more suitable for households with night storage heaters or if we use lots of electricity at night. Secondly, in the heat pumping phase/adsorption loop which will occur during the day. The useful heat of adsorption in the adsorbent pipe could be used for underfloor heating (35°C-40°C), or for domestic hot water production (55°C-°60°c) during the day. The maximum temperature lift observed from the adsorption process is 68.62°C (adsorption pipe) with corresponding COP of 0.55 to 1.39.