Usage Of Phase Change Materials Research Articles

Improvement of thermal performance of a solar chimney based on a passive solar heating system with phase-change materials

Passive solar systems such as solar chimneys need solar radiation in order to work. Therefore, they cannot present stable natural ventilation when solar energy vanishes: to have a more robust and stable condition, solar energy should be stored during the day and released back during the night. Phase change materials can save additional thermal energy during the day and release it during the night in order to facilitate stable ventilation. In this study, a CFD simulation has been performed to investigate the effect of phase-change materials (PCM) utilization in the solar chimney to provide a stable temperature and air flow rate for a guardroom. The simulation was carried out for a whole day in winter in two cases: with and without PCM usage. The results show that use of PCM as an energy storage device significantly enhances the temperature stability of the guardroom.

Parametric Study on Phase Change Material Based Thermal Energy Storage System

The usage of phase change materials (PCM) to store the heat in the form of latent heat is increased, because large quantity of thermal energy is stored in smaller volumes. In the present experimental investigation, sodium thiosulphate pentahydrate is employed as phase change material and it is stored in stainless steel capsules. These capsules are kept in fabricated tank and hot water is supplied into it. The experimental design is prepared by considering the parameters: flow rate, heat transfer fluid inlet temperature and PCM capsule shape. Experiments are conducted according to the experimental design and responses are recorded. The effect of selected parameters on TES using PCM is studied by analyzing experimental data. The experimental data are also analyzed using Fuzzy Logic to find the optimal values of flow rate, heat transfer fluid inlet temperature and PCM capsule shapes. The present work utilizes Fuzzy Logic to find the optimal parameters for designing the effective Thermal Energy Storage System (TES).

The Possibility of Phase Change Materials (PCM) Usage to Increase Efficiency of the Photovoltaic Modules

Solar energy is widely available, free and inexhaustible. Furthermore this source of energy is the most friendly to the environment. For direct conversion of solar energy into useful forms like of electricity and thermal energy, respectively photovoltaic cells and solar collectors are being used. Forecast indicate that the first one solution will soon have a significant part in meeting the global energy demand. Therefore it is highly important to increase their efficiency in the terms of providing better energy conversion conditions. It can be obtain by designing new devices or by modifications of existing ones. This article presents general issues of photovoltaic installations exposed to work in high temperatures and basic concepts about phase change materials (PCMs). The paper presents the possibility of PCM usage to receive heat from the photovoltaic module. Specially designed test stand, consisting of PV module covered with a layer of PCM has been build and tested. Current-voltage characteristics of the cell without PCM material and with a layer of PCM have been presented. Authors also describe the results of the electrical and thermal characteristic of a coupled PV-PCM system.

Numerical Analysis of the Energy Improvement of Plastering Mortars with Phase Change Materials

Building components with incorporated phase change materials (PCMs) meant to increase heat storage capacity and enable stabilization of interior buildings surface temperatures, whereby influencing the thermal comfort sensation and the stabilization of the interior ambient temperatures. The potential of advanced simulation tools to evaluate and optimize the usage of PCM in the control of indoor temperature, allowing for an improvement in the comfort conditions and/or in the cooling energy demand, was explored. This paper presents a numerical and sensitivity analysis of the enthalpy and melting temperature effect on the inside building comfort sensation potential of the plastering PCM.

Thermal energy storage with phase change material—A state-of-the art review

Abstract Recently, thermal energy storage (TES) has received increasing attention for its high potential to meet cities’ need for effective and sustainable energy use. Traditionally, energy was stored in the form of sensible heat which requires large volume of storage material. The storage volume can be significantly reduced if energy is stored in the form of latent heat and thus can benefit enormously practical applications. The existing approaches in the design, integration and application of phase change materials (PCMs) in domestic hot water tanks (HWT) and transpired solar collector (TSC) using water/air as the heat transfer media are reviewed. Crucial influencing factors are considered, including thermo-physical properties of different PCMs, different configurations of PCMs in HWT and TSC, and the limitations of each technique. This paper also discusses the existing simulation, design tools and experimental studies related to PCMs usage in HWT and central thermal storage.

Performance Improvement of a Domestic Refrigerator Using Phase change Material (PCM)

The paper investigates the performance improvement provided by a phase change material (PCM) associated with the evaporator in a domestic refrigerator. The heat release and storage rate of a refrigerator is depends upon the characteristics of refrigerant and its properties. The usage of phase change material (PCM) enhances the heat transfer rate thus improve the COP (Coefficient of performance) of refrigeration . The analysis of the experiment exemplifies the improvement of a conventional refrigeration system's COP (Coefficient of performance) considerably. Using water as PCM and for a certain thermal load it is found that the COP (Coefficient of performance) of the conventional refrigerator increased by 18-26% on average. Here the phase change material (PCM) used in a chamber built manually and which surrounds the Evaporator chamber of a conventional refrigerator. The whole heat transfer from load given to refrigerator cabinet to evaporator, evaporator to phase change material (PCM) by conduction. So the heat transfer rate of evaporator refrigerant increases remarkably which improves the COP (Coefficient of performance) the refrigeration system.

Thermal energy storage system using phase change materials: Constant heat source

The usage of phase change materials (PCM) to store the heat in the form of latent heat is increased, because large quantity of thermal energy is stored in smaller volumes. In the present experimental investigation paraffin and stearic acid are employed as PCMs in thermal energy storage (TES) system to store the heat as sensible and latent heat also. A constant heat source is used to supply heat transfer fluid (HTF) at constant temperature to the TES system. In the TES system PCMs are stored in the form of spherical capsules of 38 mm diameter made of high density poly ethylene (HDPE). The results of the investigation are related to the charging time and recovery of stored energy from the TES system.

Solar energy based thermal energy storage system using phase change materials

Nowadays for solar heating applications, usage of phase change materials (PCM) to store the heat in the form of latent heat is increased, because large quantity of thermal energy is stored in small volume. The present experimental investigation on the thermal energy storage (TES) system is developed using paraffin and stearic acid as PCM. In the present system solar energy is used as heat source to store the thermal energy in the form of sensible heat and latent heat. In the TES system paraffin and stearic acid are stored in the form of spherical capsules of 38 mm diameter. Investigation results related to the charging time and recovery of stored energy are presented. The experimental investigation showed that the charging and recovery of storage energy are less affected by the PCM materials (paraffin and stearic acid). But, utilisation of stearic acid as PCM is more economical without affecting the quantity of thermal energy stored, charging time and recovery of the stored thermal energy.