Experimental investigation of thermal energy storage system with PCM based nanofluids using solar energy

Abstract

newline Energy consumption is one of the main factors for the economic improvement of both developing and developed countries. Energy demand increases linearly with increasing industrialization and urbanization. Fossil fuel plays a vital role in satisfying energy demand. The main problem of fossil fuel is the emission of green house gases especially carbon dioxide. The usage of fossil fuel directly increases environmental pollution, change in climate and also increases global warming. To avoid such problems, clean energy is the viable solution. Solar energy is a renewable energy and is available almost globally but intermittent in supply during night time, rainy season and bad weather conditions. Solar collector is used to warm the cold water through direct sunlight. It is ineffective at night. So energy storage devices are needed to utilize the energy, when not available similar to an electrical battery. Thermal battery is needed in remote areas where electrical energy is unavailable. Phase change material is a substance which is used to store energy in the form of latent heat and then releases the energy whenever phase change process occurs. Using phase change material, thermal energy obtained from the solar energy is stored and later utilized when solar energy is unavailable. Phase change material is not only used to store solar energy but also used in waste heat recovery system. But the main drawback of phase change material is its less thermal conductivity that makes heat exchange rate insufficient. Nanosized particles that conduct thermal energy are added to the phase change materials to form nanofluids. These nanofluids considerably increase the thermal conductivity of the phase change materials and are referred as nano-enhanced phase change materials. The nanoparticles enhance the heat transfer properties and alter the physical properties of the nanofluids.