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The satisfactory performance of indirect evaporative cooling techniques (IEC) is governed significantly by the structural and design arrangement of heat and mass exchange devices. The experimental performance of the dew point evaporative cooler has been investigated in the present work with the geometrically modified flow passages for air and water. Conventionally, these passages are formed by either flat or corrugated plates. The trapezoidal corrugated plate has been used to form these passages for air and water. The laboratory trials were conducted for the different combinations of intake air temperature, specific humidity, and air velocity. The performance in terms of dew point and wet bulb efficiency is presented based on laboratory trials. The experimental results achieved dew point and wet bulb efficiencies ranging between 52% and 82% and 74% and 126%, respectively. The geometrically modified flow passages increase the heat exchange area for the same volume of a similar heat exchange device and achieve an increased thermal performance of the proposed cooler.

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Evaporative cooling is one of the techniques to lower the ambient air temperature according to the requirements. The technique includes the injection of moisture in the coming air, thus increasing its specific humidity. This technique can cool the air up to wet bulb temperature of the incoming air. In the recent past, the techniques are developed to lower the temperature of air without addition of moisture in the incoming air. These techniques demonstrate that the incoming air temperature can be approached near the dew point temperature of the incoming air. The present paper essentially focuses on the recent theoretical and experimental research of dew point evaporative coolers. Different flow configurations of heat exchange mediums, optimization of geometrical parameters, performance parameters (wet bulb and dew point effectiveness), energy efficiency ratio and energy saving potential are the key elements to study the prospects of dew point evaporative coolers over the conventional refrigeration systems operated by mechanical means. Dew point evaporative cooling technology is environmental friendly and has the potential in reducing the impact on earth due to global warming.

Human thermal comfort being one of major aspect of increasing demand of energy consumption for heating, ventilation and air conditioning (HVAC) sector. The vapor compression refrigeration systems are predominantly used in the conditioning of the air. Such systems are energy intensive on account of the mechanically driven compressor, hence, not to be considered as a long-term option. It is the need of an hour to propose alternative and sustainable method for the cooling requirements. The evaporative cooling is considered one of alternative cooling method. Such technique helps to cool the incoming air only up to the wet bulb temperature of the air. The continuous development in the past have proposed the indirect cooling methods to achieve the purpose. This method helps to achieve the temperature closer to the dew point temperature of the incoming air. Dew point evaporative cooler is an indirect evaporative cooling (IEC) technique to lower temperature of incoming air below its wet bulb temperature and near to dew point temperature. Performance parameters of dew point evaporative cooler are significantly influenced by configuration and structural arrangement of heat exchanger. The different arrangements of heat exchangers commonly used are counterflow, cross flow and counter-cross flow. This work presents performance analysis of geometrically modified dew point evaporative cooler. The commonly used geometries for the construction of heat and mass exchangers are flat plates, corrugated plates, plates with the perforations etc. In this work, the plate geometry shape is modified to corrugated trapezoidal plates for the theoretical analysis. The modified geometry helps to provide more heat exchange area for the same heat exchanger volume. The cooling efficiencies and temperatures at the outlet of the cooler were investigated for different intake air temperatures and moisture content. The incoming air temperatures are varied from 25°C to 45°C and moisture content from 7 g/kg to 26g/kg for the fixed inlet velocity of 2.5 m/s. The wet bulb and dew point efficiencies ranged from 80% to 131% and 58% to 89% respectively. The trapezoidal corrugated plates predict 17.5 % and 8.5% higher wet bulb efficiency as compared to flat plates and corrugated plate, while the dew point efficiency remains almost same.