Advanced Rooftop Controllers Tool

Posted By AirNW Admin May 19 2017

Local utilities are providing retrofit incentives for Advanced Rooftop Controllers (ARC) and Air NW has a new tool to help drive the sales.

ARCs are applied to single zone rooftop systems with constant speed fans to modulate the fan speed.  Most commercial buildings are over-ventilated because the constant speed fans are set to run when the building is supposed to be occupied regardless of actual occupancy. The ARC modulates the supply fan to reduce energy consumption. Energy savings from ARC can come from four primary sources:

1. Supply Fan Speed Controls (the majority of the savings)
2. Integrated Air-side Economizer Controls
3. Cooling Capacity Controls
4. Demand-Controlled Ventilation Controls

Air NW’s new tool will help participants motivate customers to invest in the ARC technology. The ARC calculator is a simple and easy to use form with only a few inputs regarding retrofit type, system size, utility rates, etc. The tool provides cost guidance and calculated energy savings, cost savings, estimated incentive, and customers return on investment with simple payback.

According to a study by the National Renewable Energy Laboratory, ARC products require services to install the unit, perform O&M, and deliver BMS functionality (if applicable). There is no single business model for accomplishing this, and some ARC manufacturers work through local HVAC providers for installation and O&M services.  The following table from the NREL study offers a brief summary of a few of the existing ARC systems. 

Multiple case studies illustrate ARC rooftop units saving businesses energy and money. Whole Foods, an international grocer, installed the CATALYST ARC system on 1,181 rooftop units resulting in a savings of more than 15,246 MWh across the sites that have been installed. This equates to a 42% reduction in overall energy cost and consumption for Whole Foods. In addition, the Emerging Technologies Coordinating Council completed a study in October 2016 illustrating the success of ARC for rooftop units (combined with standardized O&M practices) at two fast food restaurants.  The study found that energy consumption was reduced 8.3% and 13.2%, with additional savings secured during demand response events with demand was reduced by as much as 25.9% during tests.  In both cases, the ACR-only costs had a simple payback of less than 5 years. 

Contact the Air NW team to talk about qualifying your projects today.