Evaporative Cooling System; Simulation; Diverse Climatic Condition; Wet Bulb Effectiveness.
In present days, building energy consumption for cooling and heating purposes accounts for about 40% of entire energy consumption. The conventional air conditioning system based on vapour compression cycle is energy intensive and influences the environment through leakage of hydrofluorocarbons significantly. Even the widely used R134a has a global warming potential of 1300. Therefore, there is an immediate need for development of energy efficient air conditioning systems and it is required to develop systems limiting the usage of synthetic refrigerants. It is a well known fact that evaporative cooling mechanism is natural, eco-friendly and involves minimal energy consumption for air conditioning purpose. In addition, evaporating cooling systems are inexpensive, and involve minimum initial and running costs compared to conventional vapour compression systems. Depending on the climatic condition different types of evaporative cooling i.e., Direct Evaporative Cooling (DEC), Indirect Evaporative Cooling (IEC), Regenerative Evaporative Cooling (REC) or a hybridization of any of them can be opted to achieve better thermal comfort. In this present work, a comparative study among DEC, IEC and hybrid system has been done to estimate the potentiality of evaporative cooling in terms of energy savings and wet bulb effectiveness with a commercial software DesignBuilder followed by simulation in Energyplus with a constant cooling load for major cities namely Hyderabad, Delhi, Mumbai, Chennai, Kolkata and Srinagar in India. These different cities are strategically chosen due to a wide variation of ambient temperature and relative humidity among them. The results indicate that in direct-indirect evaporative cooling system, the temperature of supply air to conditioned space reached temperature lesser than the wet bulb temperature of process air. Whereas, energy savings up to 75% is observed by incorporating hybrid cooling system. The results also indicate that the hybrid cooling system is suitable for all weather conditions, while direct evaporative cooling system is suitable only for dry climates like Hyderabad, Delhi and Srinagar. However, the temperature reduction for the process air in direct evaporative cooler is more compared to that in indirect evaporative cooler. It may be noted that mixing the exhaust air from the conditioned space with process air resulted in further decrease in energy consumption. An extensive study optimizes the type and the size of an evaporative cooling system for different cities across India.