Solar block: Thermal capacity enhancement of concrete bricks using water and candle wax for passive indoor thermal comfort

Concrete has replaced traditional building materials and has found acceptance even in the cold climatic regions of India and the world, despite its poor insulating property. An experiment was designed to check if the thermal energy storage capacity of concrete blocks could be enhanced. This was done by using water and candle wax (as PCM) filled in plastic bottles embedded in 1 cubic foot (0.0283 cubic metre) concrete blocks. Four blocks of different concrete mixture ratios were made. Each block had 9 plastic bottles embedded within; with three of them having just water and the fourth one having a combination of water and candle wax as the heat storage material. The blocks (Solar Blocks) were tested during the summer of Ladakh. The report analysed two sets of data of temperatures recorded with a month's gap, including one on a rainy day. Temperatures above 40° C were recorded in the blocks and a temperature of above 20° C was maintained despite a complete cloudy and rainy day with cool winds in all the blocks. However, no exceptional enhancement in the storage capacity was noticed in the fourth block having the combination of water and candle wax as the storage material.