Advanced Rooftop Controls: Win-Win Energy Efficiency for Small to Medium Buildings
Oct 1, 2018
There’s something we want to yell from the rooftops, though it might sound too good to be true: advanced rooftop controls can save commercial buildings 30% to 60% of their energy consumption (ASHRAE Journal)1. AND many utilities—over 240, according to the DOE’s Better Buildings Blog— will pay large incentives covering up to 70% of the cost of that installation. This is clearly a win for the customer, the utility, and the contractors that install them. In Utah, our trade allies have completed 34 projects this year that have been incentivized through our program. We’d like to spread the word about the technology and its benefits.
What are Advanced Rooftop Controls?
Many HVAC units for commercial buildings only have one heating and cooling speed, plus a simple thermostat to regulate the temperature. Advanced Rooftop Controls (ARCs) are a digital system that allows remote monitoring, and enable control of fan speed, economizer function, and the thermostat, making it easier to maintain occupant comfort and system efficiency. Before an ARC is installed, an economizer brings in air from the outside to meet building code requirements for ventilating a building. By adding ARCs to a basic rooftop HVAC system, you have a greater ability to pull outside air in when outside temperatures are cool enough to condition the building without using mechanical cooling. It also gives the ability to close off outside air when temperatures are extreme and ventilation is not required. ARCs assess CO2 levels in the building to determine how many people are inside and whether it is actually necessary to pull in outside air. Remote monitoring provides access to system diagnostics and analysis, which gives more insight into problems and the ability to make proactive system adjustments. ARCs also have a variable frequency drive (VFD), which integrates with a constant speed fan motor and efficiently controls ventilation and space conditioning needs. ARC installations reduce maintenance costs. It improves motor control, which lessens motor wear, reducing breakdowns. Staging equipment reduces the need for mechanical cooling, extending the life of the components.
According to the US Department of Energy, “Rooftop units (RTUs) are responsible for more than 1,000 trillion BTUs per year of energy use nationwide. ARCs can reduce energy use by more than 50% on each unit. Adding an ARC to half of existing RTUs would reduce energy use by about 285 trillion BTUs. That’s equivalent to removing ten nuclear power plants or more than 70 coal power plants.“2 The DOE launched their own Advanced Rooftop Unit Campaign and recognized seven businesses, whose leadership led to an annual savings of $5 million USD and 50 GWh. They are collaborating with ASHRAE and RILA through the Better Buildings Alliance and the Federal Energy Management Program.
Utilities, Trade Allies, Distributors, and Occupants Working Together
Nexant has built relationships with manufacturers and distributors to provide trade ally training on the benefits of ARCs to improve customer awareness and adoption. Some of the distributors we work with include Honeywell, Pelican Wireless, and Transformative Wave. Nexant adds sales-based training to encourage promotion of utility incentives, and educate trade allies how to promote the cost effectiveness and energy efficiency of ARCs.
We are thankful to our trade ally network for using their existing customer base to find people willing to talk about their buildings’ RTUs. Outside of their network, we still face the typical challenges of this sector: finding the right decision maker and making the benefits and payoff period worth the effort of installation. Thanks to so many success stories and the support of utilities, distributors, manufacturers, contractors, and the DOE, the story has become much easier to tell.
We're excited to see this technology take off and be more broadly adopted in the US. We’d be happy to talk through our experiences and successes with utilities, trade allies, and customers who have questions.
2 Puget Sound Energy document per U.S. Department of Energy Advanced Rooftop Control (ARC) Retrofit: Field Test Results, July 2013.