Green Buildings: Benefits of AHU Condensate Capture

Capture and reuse of condensate from large air-handling units is a method of water conservation proven to be highly effective. Treated water doesn’t come free, so the collection of thousands of gallons of condensate each year for onsite reuse makes perfect sense. Under a Condensate Capture Potential Map published by the Department of Energy and ASHRAE, New Jersey’s potential is designated as High to Medium-High.

In a condensate capturing system, AHU condensate that is typically discarded into the sanitary sewer system is directed to a central storage tank or basin and distributed for reuse. One common use for reclaimed condensate is cooling tower make-up water. Because condensate is clean and low in mineral content (it’s essentially distilled water) and cooling tower water is treated, no additional pretreatment is required. Other uses for reclaimed condensate include irrigation, ornamental fountains and ponds, industrial process makeup, and toilet and urinal flushing. When used in applications where the water may be aerosolized and inhaled, such as sprinklers and flushing, reclaimed condensate must first be disinfected to remove any biological contamination.

Local climate, building type, size and number of cooling systems, use patterns, and outdoor air requirements are factors that should be taken into account when considering whether HVAC condensate recovery is a good choice for your facility. Large laboratory buildings, which require a great deal of outdoor air, are ideal candidates for condensate capture, as are buildings with high-density occupancy. Payback is usually quick, occurring in as little as one year.