Indoor Room Air Conditioning Using External Enclosure

This paper presents a new air conditioning system using an external air chamber enclosure. The system is based on evaporative refrigeration technique humidifying hot air from the environment by means of a new design humidifier. Temperature at the air chamber is set up according to the required comfort conditions. The air chamber plays the role of a heat collector from indoor room radiative energy. This new system avoids thermal gradient inside the room improving the comfort because of a more homogeneous temperature distribution. Maximum thermal amplitude at the air chamber and indoor room is of 2°C. Theoretical analysis has been developed to determine the refrigeration energy consumption matching values with literature data. Experimental tests have shown a good correlation with theoretical prediction, within accuracy of 7.8%, close to the 8.2 % uncertainty of experimental measurements. A significant reduction in energy consumption has been achieved with COP values up to 4.8 for 31.5°C of ambient temperature. COP increases linearly with ambient temperature and enhances efficiency of air conditioning compression units above 31.5°C, although shows poorer performance below 29°C, what makes the new system especially suitable for hot climates. The result of the evaporative refrigeration at the air chamber has permitted the reduction of daily thermal amplitude from 17°C at the outside, to only 2°C, at the inside. COP of the new system moves from 1.1 to 4.8 within ambient temperature limits, 25.5°C to 31.5°C. Maximum amplitude of temperature at the indoor room has been of 2°C, with a maximum thermal gradient that has not exceeded 0.5°C/m.