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In order to reduce energy consumption in buildings, a solution using phase change materials (PCMs) as thermal energy storage (TES) is presented. During summer nights, cold is stored and delivered during the day to reduce cooling load, whereas in winter, heat from solar air collector is stored for heating during morning and evening hours. Proposed is a stand-alone unit suitable for offices, which consists of plates filled with paraffin RT22HC. The objective of the paper is to examine the functioning of the suggested TES system on an annual basis and to explore the feasibility of using it for both, cooling and heating. First numerical model is set up, which assumes 2D geometry and evaluates thermal response, calculations are carried out in Fluent. Then validation of simulations with experimental results is established. Finally the feasibility of storage unit on an annual basis is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: This article presents an experimental analysis of cooling buildings using night-time cold accumulation in a phase change material (PCM), otherwise known as the “free-cooling principle”. Studies of the ceiling and floor free-cooling principle, as well as passive cooling, are presented. The free-cooling principle is explained and some of the types of PCMs suitable for summer cooling are listed. An experiment was conducted using paraffin with a melting point of 22 °C as the PCM to store cold during the night-time and to cool hot air during the daytime in summer. Air temperatures, heat fluxes and heat as a function of time are presented for different air velocities and inlet temperatures. [ABSTRACT FROM AUTHOR]

Abstract: One of the technologies which help to reduce energy consumption is the thermal energy storage for cooling applications where the cold is stored in phase change materials (PCMs). Such materials would be suitable for use in buildings because they can store a large amount of cold and phase change occurs at a constant temperature, thereby increasing thermal comfort. The aim of the study was to investigate how and where PCMs are used in the cooling systems, how are these systems related to buildings, if they provide lower energy consumption, how the indoor temperatures change due to PCMs and if the indoor air conditions improve. In this article are firstly presented materials that are suitable for such applications and desirable properties for use in such applications. A review of cooling systems follows, which are divided into four groups, namely: free cooling applications, encapsulated PCM systems, air-conditioning (AC) systems and sorption cooling systems, both with integrated PCMs. All studies have shown that the use of PCMs helps to improve energy performance of buildings, the problems were encountered in heat transfer and the amount of PCM needed for storage. These topics are also worthy of further research. [Copyright &y& Elsevier]