Energy recovery wheels cut outdoor air energy costs and minimize equipment
design loads
By: Marianne Wilson
Airxchange®’s Brushless DC Motors with integrated speed control are now available with energy recovery
wheels. A more reliable and cost effective solution than conventional VFD options, they require no
external drives and operate on a linear signal to regulate speed for control of temperature and Brushless
DC Motors are equipped with integrated speed control and energy-recovery wheels. The product requires
no external drives and operates on a linear signal to regulate speed for control of temperature and
humidity.
Retailers and other building owners are caught between two powerful and conflicting forces: the need
to lower energy and equipment costs, and the need to meet or exceed outdoor air ventilation
regulations for the health and comfort of customers and employees alike. Indeed, studies have proven
that outdoor air ventilation creates a healthier work environment. However, as outdoor air rates
increase, so does the size, cost and operating expense of HVAC systems.
To address the challenge, many owners are deploying site-recovered energy technologies, such as
energy recovery ventilation (ERV). Designed to operate with new or existing HVAC units, ERV
technology provides an affordable means to simultaneously cut HVAC energy costs without
compromising outdoor air ventilation requirements.
“Energy recovery wheels, also known as enthalpy wheels, resolve the conflict between indoor air
quality and energy conservation by recovering site energy contained in building exhaust air,” said
Stephen J. Pargeter, VP product engineering, Airxchange®, Rockland, Mass., which manufactures
energy recovery ventilation wheels. “Up to 80% of this energy is recycled to precondition outdoor air,
resulting in reduced HVAC load and operating cost.”
For new and replacement projects, energy recovery costs are typically offset by lower HVAC system
first costs, while up to 80% reductions in outdoor air fuel consumption provide healthy returns for the
life of the HVAC system, according to Pargeter.
Energy recovery wheels may also be used to improve the efficiency of relatively new HVAC systems
by up to 40% with one- to three-year paybacks when supported by the local utility. They also can help
retailers with their environmental initiatives.
“Energy recovery wheels enable building owners interested in marketing green, healthy buildings to
increase outdoor air levels above minimum code, earning LEED points and reducing the risk of indoor
air quality complaints,” Pargeter explained.
Energy recovery wheels work by transferring energy by rotating between outdoor air and exhaust
airstreams to transfer heat and moisture from one airstream to the other.
The total energy saved depends on the wheel’s effectiveness and the difference in temperature and
humidity between the two air streams. A bigger differential drives larger energy savings.