Experimental Study of Forced Circulation Solar Air Heating System with Phase Change Materials (Paraffin Wax) Energy Storage | Original Article

ABSTRACT:

ABSTRACT

The continuous increase in the level of greenhouse gas emissions and rise in fuel prices are the main driving forces behind efforts for more effectively utilize various sources of renewable energy. In many parts of the world, direct solar radiation is considered to be one of the most prospective sources of energy. In Bihar mean yearly global solar radiant exposed is 18.31MJm–2day–1, this is sufficient amount of energy for use. This energy can be used as electrical energy or thermal energy. The storage of thermal energy for continuous operation in solar air heater is major challenge. The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. So, this study is concentrated on the thermal performance of storage type solar air heater by phase changed material (PARAFFIN WAX). A series of experimental tests undertaken on plain aluminium absorber plate which was placed over the paraffin wax bed (2 m×0.30 m×0.10 m). 490 aluminum fins (∅ 4 mm×100 mm) are welded on other side. These fins are dipped into the PCM’s bed for better conduction of heat from absorber plate to PCM and vice-versa. The experiment was conducted day and night (24 hr.) continuously after 1 hr. interval under no-load conditions over the ambient temperature range of 22-47ºC, and a daily global irradiation range of 984.53- 325.051W/m2. The experimental investigation shows that the maximum temperature rises up 60.5ºC in mid days. The temperature difference between output and input ranges of 1.5 ºC – 7.50ºC in morning time (06:00 hr) for different mass flow rate of air (0.015Kg/s, 0.020 Kg/s, 0.025 Kg/s). The average temperature rise of atmospheric air is 8º C, in 24 hours consistently. The time average instantaneous collector efficiency is 37.16 %. So, this setup can be used for various applications such as space heating, in painting shop, crop drying and poultry egg incubation for 24 hours application. Latent heat thermal energy storage is basically attractive technique because   it   provides   high energy storage density.  When comparing to conventional sensible heat energy storage systems, latent heat energy storage system requires a smaller weight and volume   of material for a given   amount   of   energy.   In addition, latent   heat   storage   has the   capacity to store heat of   fusion   at   a constant   or   near constant   temperature   which   respond to the p has e transition temperature of the phase change material (PCM).