WaterFurnace: Waterside Economizer

WaterFurnace is pleased to announce the availability of the waterside economizer option. This new option is available on 2-6 Ton horizontal and vertical Versatec Base (UB), Versatect Ultra (US), Envision2 Compact (NB), and 7-25 Ton horizontal and vertical Envision Large (NL) products. Units with this option can be operated in a standalone configuration or via a network DDC control.

According to the U.S. Energy Information Administration, HVAC systmes consume 25% to 49% of a typical office building’s energy use. Improving the efficiency of the HVAC system makes a major impact on overall energy use and provides significant savings to the building owner. Adding an economizer to the HVAC system makes cooling more energy efficient by using resources such as cool air or water in place of operating a compressor. Depending on design conditions, economizers can provide up to 100% of cooling load requirements.

WaterFurnace waterside economizer option allows the use of a building’s interior loop water to provide “free” cooling. It works by passing air through a coil cooled by loop water rather than going through a coil cooled by mechanical refrigeration. The economizer contains a water-to-air heat exchanger, a 3-way valve, and controls that manage the flow of water through the heat exchanger. The economizer is mounted in line with the heat pump’s return air flow. When cooling is required and the building loop water temperature is below the economizer setpoint, typically 45 degrees Fahrenheit, water is passed through the economizer. Air is drawn through the cool economizer and the heat pump’s compressor is turned off. Cooling is then provided by the economizer, reducing energy use.

WaterFurnace Advantage

The greatest benefit of the WaterFurnace waterside economizer is energy savings. A heat pump’s compressor consumes the majority of power required to provide cooling. Turning the compressor off provides substantial savings. An added benefit is improved life of the compressor through lower run hours and less cycling. When mandated by code, the waterside economizer can also help buildings comply with ASHRAE Standard 90.1. See “WaterFurnace Code Review” for information on the requirement of economizers on WSHPs.

Waterside economizers have advantages over airside economizers as well. Because they are not directly subject to outdoor air conditions, waterside economizers can provide longer operating hours and better humidity control. They also have fewer mechanical components and are less prone to failure. Airside economizers can fail in the open position, leading to much higher energy costs.

Typical Applications
Candidates for waterside economizers include commercial buildings that have simultaneous heating and cooling loads. For example, during cool weather a building may require heating around the perimeter and at the same time require cooling for the core space. The perimeter heating will cool the loop water which in turn flows through the economizers that are cooling the core space. The heat absorbed from the core space is then put back into the loop, providing higher efficiencies for both heating and cooling. Waterside economizers are also a good fit for buildings where it is difficult to use an airside economizer. An example of this would be a multi-story building using separate air handlers for each floor and no central air delivery system.

Print Friendly, PDF & Email

Comments are closed.