Present State of Cooling, Energy Consumption and Sustainability

The rise in temperature is an on-going issue due to global warming. The air-conditioning demand is expected to be triple by 2050 to provide comfortable environment at offices and residential buildings. In most of the deserted countries, the annual cooling degree days are over 4000 due to harsh weather conditions. Presently, over 6 billion air-conditioning units are installed globally including refrigeration systems and it is expected to increase exponentially in next decades. This inexorable growth in air-conditioners capacity not only increasing the energy demand due to low performance of conventional systems but also contributing a huge amount of CO2 and greenhouse gas emissions. The levelling-off the efficiency of conventional chillers at 0.85 ± 0.03 kW/Rton coupled with chemical-based refrigerants is the major limitation of conventional mechanical chillers covering 90% world air-conditioning market. To continue sustainable development, out-of-box solutions are required. The future air-conditioning systems must achieve the performance level of 0.60 ± 0.03 kW/Rton to fulfil the cooling demand in sustainable manner. Decoupling of dehumidification from cooling is one of the solutions to overcome the conventional system limitation to achieve satiable cooling goals.