WaterFurnace International Inc. recently introduced a waterside-economizer option to its line of commercial geothermal and water-source heat pumps.
Available on 2- to 6-ton horizontal and vertical Versatec Base and Versatec Ultra Envision2 Compact and 7- to 25-ton horizontal and vertical Envision XL products, the option allows the use of a building’s interior-loop water for “free” cooling.
The waterside economizer works by passing air through an internal coil cooled by loop water, rather than by mechanical refrigeration. The unit contains a water-to-air heat exchanger, a three-way valve, and controls that manage the flow of water through the heat exchanger. When cooling is required and building-loop water temperature is below the economizer setpoint, which typically is 45°F, water passes through the economizer. Air is drawn through the cool economizer, and the heat pump’s compressor is turned off. Cooling then is provided by the economizer, reducing energy use. Compressor life is extended as a result of reduced run hours and less cycling.
“Depending on design conditions, economizers can provide up to 100 percent of cooling-load requirements in a building,” Tim Litton, director of marketing communications, WaterFurnace International, said. “This makes cooling much more energy-efficient and translates to significant energy savings for the building owner.”
Because they are not directly subject to outdoor-air conditions, waterside economizers provide longer operating hours and better humidity control than airside economizers. Also, they have fewer mechanical components and are less prone to failure.
Water-source heat pumps that use the waterside-economizer option can be operated in a standalone configuration or via network direct digital control.