Energy Recovery Ventilators: Perfect for LEED and WELL

Josephine Gurch
Writer
September 7, 2016

Optimize Energy Performance

ERVs can be an integral part of energy saving strategies for the LEED Optimize Energy Performance credit.

Optimizing energy performance is a team effort.

Credit: Public Domain Image

Residential and commercial buildings consumed more than 40 percent of the world’s primary energy in 2015... and the commercial building energy sector alone represents 20 percent of all U.S. energy costs.

How does that figure break down?

Data in a new infographic from Spaceway (a U.K. firm that innovates new ways to maximize space) shows that the total amount of energy a building loses can be traced back to the following components:

Roofs (25 percent)
Windows (10 to 20 percent)
Doors (15 percent)
Walls (50 to 60 percent)

As a result of these losses, building owners are seeking to design tighter, more insulated envelopes. However, tighter envelopes mean a greater reliance on mechanical ventilation for fresh outdoor air to be conditioned within the building.

Commercial building owners seeking LEED certification are often faced with choosing between two seemingly opposing forces: the need to lower energy costs, and the need to meet or exceed outdoor air ventilation regulations.

Energy Recovery Ventilators can help project teams achieve the LEED Optimize Energy Performance credit, which provides an affordable way to simultaneously cut HVAC energy costs without compromising outdoor energy ventilation requirements. These beneficial, but seemingly counterintuitive, effects are also emphasized and encouraged in the new WELL Building Standard.

LEED’s Optimize Energy Performance credit offers strategies to help avoid the environmental and monetary losses that come with out-of-sync systems by motivating project teams to envision and design the very opposite -- an integrative whole.

Energy Recovery Ventilators and LEED

HVAC systems are responsible for up to 44 percent of a building’s utility bill. A large portion of a building’s HVAC energy can be attributed to conditioning outdoor air ventilation.

As fresh air is drawn into the building, stale air is expelled, along with site-generated energy used to condition it. This energy-rich exhaust air represents the largest source of wasted energy in most commercial buildings.

The installation of an energy recovery ventilation (ERV) system can resolve the conflict between indoor air quality and energy conservation by recovering otherwise wasted energy contained in building exhaust air.

ERVs used in commercial building enthalpy wheels) to precondition fresh outdoor air with the recycled energy.

Because the heat exchanger makes use of pre-existing temperatures, it relieves a building’s HVAC system of the need to expend energy warming and cooling incoming air.

One company, Airxchange, has been a pioneer in the evolution of ERV technology for 30 years.

Founded with the explicit purpose of reconciling the conflicting demands of energy optimization and indoor air quality, the manufacturing company’s products have accumulated over 250,000 installations and obtained something of an omnipresence on HVAC markets.

The focus of the Airxchange portfolio is currently on energy recovery wheels (also known as rotary heat exchangers), which recycle 70 to 80 percent of the total energy found in exhaust air.

An Airxchange white paper on ERV technology points out that when this energy goes to waste, the high energy costs incurred lead to lower property values and profit margins. By recycling energy from the exhaust airstream instead, Airxchange wheels reduce outdoor energy costs by 60 to 80 percent. This enables the broader ERV system to operate at a third of the cost of its conventional counterpart.

Airxchange wheels also increase HVAC efficiency by up to 40 percent. Their design allows for greater control over humidity levels indoors, which prevents the growth of mold and other contaminants within the building envelope protecting the building and its occupants from the negative effects of elevated humidity.

The wheels’ removable energy transfer segments, for instance, are unique. The sections make for a hassle-free cleaning process that keeps contaminants at bay without extraneous tools or constant upkeep. Patented wheel designs and non-corrosive energy transfer material also help to minimize unwarranted moisture, in addition to boosting the components’ endurance and lifespan.

To ensure that project teams have the data needed to configure Airxchange wheels into their energy designs and cost estimates, the technology comes with performance modeling software that predicts their return on investment (ROI), along with HVAC capabilities, total energy reduction and environmental impact.

ERVs and WELL Synergy

With Airxchange wheels, cutting energy costs doesn’t come at the expense of outdoor air ventilation.

Outdoor air levels can be doubled, or even tripled, when ERV technology is deployed. Maximized use of outdoor air ventilation, according to the Airxchange white paper, produces high-quality indoor air and therefore a healthier work environment.

In addition to squaring with the ASHRAE ventilation standards adopted by the LEED Optimize Energy Performance credit, Airxchange wheels embody WELL Feature 03: Ventilation Effectiveness.

The WELL feature draws from the same ASHRAE requirements to engineer pollutant-free building interiors. Its inclusion in the WELL Building Standard for Air illuminates the role ERVs play in not only ecologizing energy performance, but also in eliminating dangerous airborne contaminants.

Evidence of building health also happens to be one of the green building sector’s most marketable assets, giving owners an opportunity to attract conscious consumers and raise property value.

ERVs in SOU Project Optimize Energy, Space and Creativity

By granting project teams considerable autonomy in their choice of equipment, materials and resources, the LEED Optimize Energy Performance credit creates space to explore and experience the full spectrum of green technology.

That built-in flexibility galvanizes cooperative decision-making between departments, allying designers, engineers, contractors and other team members in common pursuit of rewards. Apparatuses erected within such conditions are, on the whole, more cohesive and effective than those orchestrated through separate channels at separate times.

The Southern Oregon University (SOU) and Rogue Community College (RCC) Higher Education Center is the Oregon University System’s first building to receive LEED Platinum Certification. Its high-efficiency HVAC system, supported in part by energy recovery wheels, is instrumental in reclaiming nearly $40,000 in energy savings for the institution each year.

The success of the Higher Education Center demonstrates the extent to which a regimented design scheme makes way for bigger payoffs. The building’s energy performance even hovers a full 37 percent above the bottom lines of Oregon's rigorous energy efficiency specialty code.

Regulating energy design, rather than reining in creativity and limiting prospects, pushes professionals to pioneer operational and mechanical building systems -- which, in turn, leads to diminished peak loads and enhanced ecological oversight. LEED’s Optimize Energy Performance credit integrates building and design strategies that open up a gateway to these benefits. You can learn more about Optimize Energy Performance here.