Harvesting Air Conditioning Condensation Could Replace Cities’ Potable Water Use

While looking for ways to make homes and offices more efficient, building managers realized that something as seemingly insignificant as water droplets from the bottom of air conditioning units has the potential to quench thirst. of thousands of people.

While the drops don’t seem like much, they really do add up. Microsoft reports that its 46,000-square-meter offices in Herzliya, Israel, annually collect 3 million liters of condensate from air conditioners, which they use to irrigate campus flora and cool the building.

This is equivalent to all annual indoor and outdoor water needs of at least two family dwellings.

In the US, a building on the campus of Rice University, Houston, has an air conditioning unit that generates 15 gallons condensate per minute, and they believe their entire campus could provide 12 million gallons annually.

Taking advantage of this potential, city governments and green-conscious offices in the United States are experimenting with different ways of using a resource that for many years has only served to leak into the walls of buildings, giving them a dirty and run-down appearance.

It is not the most difficult challenge, as condensation is a process that is quite easy to control and predict. For example, if the surface on which the condensation occurs is uneven, the water will always run to the narrowest point before accumulating enough mass to fall. Placing a cistern or gutter below that point is essentially the only major step required, or adding a water pump if you need to send the water uphill.

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Additionally, many air conditioning units come with rubber condensate removal pipes that drain moisture to a specific location, such as a patio.

Smart condensation

In Austin, Texas, a parched and farsighted place, the approved by the city council an incentive program that will offer money to large building managers if they can reuse air conditioning condensate, greywater or rainwater for non-potable needs on the site.

Bloomberg reports that between two buildings, the 56-story Austonian residential skyscraper and the Austin Central Library, its water recycling methods save the city 362,800 gallons of water per year.

Systems that go the extra mile, saving one million gallons of drinking water, are eligible for $ 250,000 in funding, doubling to $ 500,000 if the systems can save the city three million gallons.

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Another hot and arid city, Tucson, is demonstrating the use of these water conservation systems. The University of Arizona College of Architecture, Planning and Landscape Architecture uses 100% recycled water in its Sonora Landscape Laboratory.

Situated on what used to be 1.2 acres of parking, this miniature piece of the Sonoran desert uses 95,000 gallons of water, all collected from air conditioning condensate to water desert gardens and to continually fill a pond where wildlife local can drink.

Other non-potable water integration features, such as roof runoff, gray water from the potable water source, and backwashing from a sand filter, along with HVAC condensate will save an estimated 230,000 gallons of drinking water per year.

There are several guides online on how to build your own recycling system, or the basic principles to collect your own air conditioning condensate, if you live in a dry climate and want to take advantage of this technological boon.

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