Evaporative Cooling for Hotel Kitchen Make-up Air

Make up air for kitchens is a big consumer of energy.  This is particularly true for the cooling side.  For locations where the humidity is low in the summer, an evaporative pre-cooler is an economical solution.  The evaporative cooler lowers the outside air temperature by evaporating water into the air stream.  The humidity of the airstream rises, but if the outside air is dry to begin, the increase in humidity is tolerable.  Palmdale, California is just such a location. 

The photo  below  shows an evaporative cooler mounted to the outside air intake of a standard gas fired make-up air unit.


This shows the wetted media which exposed the airstream to the water.    This media is constantly moistened by a water supply and a pump. 

The photo below shows the sump under the media.  In a sense, this is nothing more than a cooling tower where the airstream is pulled into the make-up air unit.


To see the performance, the following sequence of pictures shows the temperature starting at the outside air intake, then the air just downstream of the wetted media, and finally at the outlet grille in the kitchen.


Note that the temperature drops from 75 degrees outside to 58 degrees after the moisture is add and then finally back up to 66 degrees where it enters the room.  The increase from 58 to 66 degrees is due to the fan energy and the heat gain of the ductwork above the ceiling.

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