Modelling and performance evaluation of a solar driven double lift absorption chiller in the Indian context

This work focuses on the investigation of the potential of a solar driven double lift absorption chiller for cooling in India. Due to its extreme hot climate, the cooling requirements are very high in India. Forecasts suggest that the electricity consumption from the air conditioning in 2030 would be close to 239 TWh/yr, which corresponds to an extra peak electricity demand of 143 GW. Currently the majority of the cooling requirement is satisfied by machines working with vapour compression cycle. Among the different technologies for solar cooling, double-lift absorption chillers can be driven by relatively low heat and can be air-cooled. These systems can be driven by solar thermal collectors which provide heat energy to the absorption chillers. The absorption cycle working with NH3-H2O is selected as it is more suitable for the Indian climate. Simulations for the assessment of the performance of the chiller are performed in Trnsys for New Delhi, Mumbai, Kolkata and Chennai. The building model is developed keeping in mind the typical characteristics in India. As a part of the assessment, the control strategy of the air handling unit is fine tuned to intelligently reduce the cooling demand. The performance of the machine is best in Mumbai with average COP of 0.25 and solar fraction of 18%. The machine achieves COP of 0.35 in winter but the cooling requirement is low in that season. In summer the COP is found to be as low as 0.15 due to high ambient temperatures.