Parametric analysis of a packed bed thermal storage device with phase change material capsules in a solar heating system
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Parametric analysis of a packed bed thermal storage device with phase change material capsules in a solar heating system application Research Article
Long Gao, Gegentana, Junchao Bai, Baizhong Sun (), Deyong Che, Shaohua Li School of Energy and Power Engineering, Northeast Electric Power University, Jilin 132012, China
Abstract
Keywords
The goal of this study is to investigate the effect of key design parameters on the thermal performance of the packed bed heat storage device by numerical calculation. A one-dimensional, non-equilibrium packed bed latent heat storage mathematical model was established and the applicability of the model was verified. The results demonstrate that the inlet temperature of the heat transfer fluid (HTF) had the greatest influence on each index. When the inlet temperature increased from 333 K to 363 K, exergy destruction increased threefold, effective heat storage time decreased by 67%, effective heat storage increased by 38%, and exergy efficiency decreased by 11%. The decrease of the capsule diameter had a positive effect on each evaluation index. According to the sensitivity analysis, the order of importance of each parameter within their variation range was HTF inlet temperature, HTF flow rate, PCM capsule size and PCM initial temperature.
packed bed thermal energy storage, solar heating system, performance evaluation, parametric analysis
Article History Received: 10 December 2019 Revised: 22 June 2020 Accepted: 30 June 2020 © Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
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Introduction
E-mail: [email protected]
Building Thermal, Lighting, and Acoustics Modeling
The burning of fossil fuels results in significant adverse effects, including contributing to global climate change. In recent years, the haze phenomenon has become increasingly severe during the heating season in northern China. Solar heating, one of several clean energy heating alternatives, is being widely used in Denmark and other European countries (Dickinson and Cruickshank 2011). However, its periodicity and intermittency have restricted more extensive applications of this solar heating technology. Improving the energy utilization efficiency of the solar heating system in cold climate regions and the thermal performance of the thermal energy storage unit is a key step towards providing a continuous stable heat supply from a clean energy source. Thermal storage includes physical and chemical thermal storage, with physical storage split into sensible and latent thermal storage. Compared to sensible thermal storage, latent thermal storage has attracted more attention because of its higher storage density. Phase change materials (PCM) are used as the medium for latent thermal storage and are a focus of much critical research. Commonly used PCMs
include paraffin, fatty acids, and inorganic hydrated salts and their thermal storage capacity can reach 2–3 times that of water. However, these materials are also characterized by their low thermal conductivity, which can r
