Evaporative cooling is a modern technique for producing cold air, suitable for air conditioning applications, and presenting the following advantages:
- reduced power consumption, up to 80%,
- environmentally friendly behaviour,
- elimination of dangerous refrigerants.
For research purposes, the Laboratory of Applied Thermodynamics, Cooling Technology & Refrigerated Vehicles has installed and operated an experimental evaporative cooling unit, which follows the Maisotsenko cycle. This cycle uses an original geometry to maximize cooling efficiency. In sum, the advantages of the Maisotsenko cycle over simple evaporative systems are:
- ability to achieve low temperatures, generally lower than the ambient wet bulb temperature,
- greater concentration of power and relatively reduced water consumption,
- low pressure drops, given the absence of a porous medium.
The results of the experimental process demonstrated the effectiveness of the cooler as suitable even for the complete replacement of conventional coolers, providing fresh air at almost constant temperature of 21oC – 22oC and humidity of about 55%. The possibility of improving the chiller with independent control of air supply of the streams was also examined, to investigate further water savings and lower final temperature for the cold air. It was experimentally proven that reducing the cooling current supply by 50% lowers the final temperature by up to 2.5oC, allowing the chiller to cover even more difficult cooling loads. In addition, 50% decrease in the working stream leads to water saving of approximately 40%, with the final air being less than 1.5oC warmer than nominal supply values.
