Building Retrofits

One of my research focuses is evaluating retrofit strategies for improving the energy efficiency and thermal comfort of residential buildings in India. Initially (between 2018-20), I was very excited about the use of phase change materials (PCM) in the building envelope as a solution for improving the energy efficiency of new and existing buildings. PCMs work on the principle of latent heat thermal energy storage. During periods of high heat gains (day-time), they undergo phase transformation (typically solid to liquid) and store the excess thermal energy, which is released back during periods of low heat gains (night-time). By this process, they seem to reduce the cooling energy consumption and peak cooling loads and delay the peak loads to later hours. However, my research [Rai, 2021] showed that, regardless of the amount of latent heat stored by the PCM layer, the daily heat gains and cooling loads were equal for wall configurations having equal thermal resistances. Thus, PCM integration was found to be ineffective in reducing the daily heat gains or the cooling load requirements, although it seems suitable for peak load management. Another paper from my research [Sharma and Rai, 2020] compared PCM-integrated and insulated envelopes for reducing the summer cooling needs of Delhi homes. We found that insulation is not only much cheaper to use than PCMs but also outperforms PCMs in terms of reducing envelope heat gains and peak cooling loads. So, I am not so sure about the PCM technology anymore. 😔

So, after my brief (was it unsuccessful? 🤔) stint with PCMs, my research is now focused on studying insulated envelopes for improving buildings' energy efficiency!

Stay tuned for more details!