Better HVAC Controls Spell Big Commercial Building Savings

The country’s commercial building owners could save an average of 38 percent on their heating and cooling bills if they installed just a handful of controls designed to make their HVAC systems more energy efficient. Says who? Says researchers from the U.S. Department of Energy‘s Pacific Northwest National Laboratory (PNNL), that’s who.

According to a recent report, the key to more efficient HVAC systems — which handle the heating, ventilation and air conditioning  in buildings — are additions like air-side economizers, which use cool outside air to chill the building (instead of creating cool air with the HVAC compressor); supply fan speed controls that slow or speed up the ventilation fan that circulates the building’s air based on whether or not a desired temperature or amount of fresh air has been reached (instead of continually running the fan at full speed); cooling capacity controls that run the HVAC compressor at different speeds, likewise based on need; and demand-controlled ventilation that slows or speeds up fans and air intake based on carbon dioxide levels inside the building (instead of running ventilation fans at a constant rate).

PNNL commericial building HVAC graphic

image via Pacific Northwest National Laboratory

Unfortunately, the controls that could provide these staggering savings aren’t widely available commercially at present, but the report’s authors hope their analysis will encourage manufacturers to expand production. “The potential savings from adding advanced controls to existing packaged air conditioners with gas furnaces is enormous,” said PNNL engineer Srinivas Katipamula, who led the study, in a statement. He goes on to note that the estimated savings for commercial buildings vary widely by region and local energy prices, ranging from a whopping 67 percent cost savings in San Francisco to a still-impressive 28 percent in Seattle.

The estimated savings such energy efficient controls hold for commercial building owners were based the researchers’ computer modeling and simulation of building energy usage, which allowed them to track the effects of various HVAC energy efficiency controls in various types of buildings over time. Using the building simulation software, called EnergyPlus,  researchers created computer simulations taking into account 15 climate zones in 16 major U.S. cities.

Susan DeFreitas has covered all manner of green technology for EarthTechling since 2009. She is a graduate of Prescott College for the Liberal Arts and the Environment, and has a background in marketing green businesses. Her work on green living has been featured in Yes! Magazine, the Utne Reader and Natural Home.

    • Do It Right HVAC

      Cooling a building by economizer strategies must be done carefully. This requires an enthalpy control that is set up properly. Done incorrectly, a building in a humid climate could load up with moisture even when the outdoor dry bulb temperature may be suitable for cooling the interior. Generally, outdoor air dew points below 55 degrees with outdoor dry bulb temperatures less than 70 degrees can provide comfort cooling without introducing excess humidity concerns.

      Many existing buildings and their mechanical systems could likely realize energy savings if their control systems would undergo a commissioning effort. Even if commissioning took place after installation, a few years down the road can lead to drift away from those benchmarks, provided they were correct from the start.

    • Keith Smith

      A new HVAC system controller has just entered the market the DLC Demand Limiting Controller which is a low cost networked controller system. The DLC System optimizes multiple HVAC units alternating operation times – reducing peak demand charges which lowers energy costs. The DLC controller is experiencing Savings Up to 16% on Electric Bills, which is proving to be our most cost effective solution for our commercial accounts today. This patent pending networked controller is the only system of its kind on the market today. Typical payback for this system installed is less than 18 months. The system is a fraction of the cost compared to the Johnson Controls system and also the Carrier controller, and offers automated demand limiting and air intake economizers.  See product video at, http://usenergyaudit.com/product/product-video/ .