Project Info

Project Title 
Indirect Evaporative Air Conditioners Added to Existing RTUs
Project Number 
Investor Owned Utilities 
Commercial, Public
Project Year(s) 
2012 - 2014

This report documents the results of a pilot field study designed to characterize performance for two indirect evaporative air conditioning products. These systems each utilize indirect evaporative heat exchangers that enable water evaporation to cool a building without adding moisture to the air that is supplied to the conditioned space. These air conditioners do not have compressors, and the only major energy consuming component is a fan. Unlike conventional vapor-compression air conditioners, indirect evaporative systems actually become more efficient as outdoor temperature increases.

This study was performed in parallel and/or in sequence with four other studies, all of which assessed the performance of RTUs that employ evaporative technologies in different ways or configurations. These include:

• A lab assessment of four direct evaporative condenser pre-coolers, and one air supply indirect evaporative pre-cooler.

• A field assessment of indirect evaporative cooling for a mall in Fairfield, CA in which a new RTU was retrofitted with a direct evaporative pre-cooler at the condenser inlet, and a water to air heat exchanger at the ventilation air inlet.

• A field assessment of an indirect evaporative unit, serving as a dedicated outside air supply (DOAS) at a restaurant in Rocklin, CA.

• Lab and field assessments of a Munters hybrid unitary dedicated outside air supply (DOAS) system.

Project Report Document

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