Windy City Reps

Energy Recovery Ventilator (ERV) Systems: Improving Efficiency and Indoor Air Quality (IAQ) in HVAC

November 5, 2021

“Crack open a window!” The idea that fresh outside air is important to people inside has been around since the first time that phrase was shouted. Today, we have many more options available to us than just opening a window. However, our needs and concerns have become significantly more complex in the modern world. HVAC technology is advancing quickly to address these needs. ​Energy recovery ventilators (ERV), one of the latest technological advancements, are both energy-efficient and powerful. Their qualities make ERV an ideal choice for larger facilities and commercial buildings, allowing building owners to keep occupants comfortable while keeping utility costs low.

​The Basics of Energy Recovery Ventilator System Operations

​An ERV system works on the zeroth law of thermodynamics, which states that if two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. So, in terms of HVAC, if hot air is being exhausted from an HVAC system in the winter, you could use the energy it contains to preheat the outside air as long as the two were passing near each other. It also works in reverse: if cool air from the inside of the building passes hot outside air coming through the system, it will help cool it down.

​In addition to heat transfer, humidity is also transferred between the two airstreams. This can be extremely valuable to ensure that humid summer air does not lead to condensation when it is cooled and so on. Systems that do not include humidity transfer are called heat recovery ventilator (HRV) systems.

​The Benefits of Energy Recovery Ventilator Systems

​Anytime you can reuse any energy downstream in a process, it tends to save property owners and building managers on utility bills. For some HVAC engineers, however, the scale of the savings may not be immediately apparent. Indoor air quality and incoming fresh air are required elements given building codes and the standards set by the American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE).​

By using the outgoing temperature to help temper incoming fresh air, ventilation HVAC costs can be reduced by up to 40% over conventional ventilation options. These savings can continue for 20 to 25 years, or the expected lifetime of the units. This also leads to a quicker payback period, a key consideration for engineers working within capital project constraints.​

ERVs also provide substantial benefits when compared to conventional options for ventilation units within commercial HVAC systems. ERVs require smaller-diameter ductwork than other ventilation measures, ensuring they fit in smaller building envelopes.

​Further, because they reduce the load on the overall HVAC system when it comes to heating and cooling spaces, ERVs lengthen the lifespan of older furnaces, boilers, and air conditioning systems. Just as they reduce costs by about 40%, they also reduce the overall HVAC load by a similar percentage.

​On the Horizon: Future Regulations

​Maintaining comfortable temperature and humidity levels in buildings is currently the largest single utility driver. About 70% of electricity goes to this purpose. That certainly is not sustainable over the longer term.​

The U.S. Green Building Council’s LEED (Leadership in Energy and Environmental Design) certification programs are considered some of the most stringent requirements for maximum energy efficiency and occupant health protection via interior air quality measures. They mandate very efficient energy recovery ventilation systems as part of any commercial HVAC system.

So, too, has ASHRAE in its Standard 189.1. It focuses on not just energy efficiency, but also indoor environmental quality, one of the key metrics where ERVs can make a substantial difference. The standard requires ERVs to have a recovery effectiveness of at least 60%.​

These increased efficiency requirements are only going to trickle down into the commercial HVAC specifications, regardless of whether a building owner is seeking LEED certification because of a project. Keeping abreast of ERV developments will help in designing ever more advanced systems.

​Get Help with Your Energy Recovery Ventilator Specifying Needs

​Many HVAC engineers are aware of the growing popularity of energy recovery ventilator systems but are not always sure if they can make them work within the budget of an architect’s plans melded with a commercial construction company’s capabilities.At Windy City Representatives, we represent the leading commercial HVAC manufacturers, including the top names in energy recovery ventilator systems. Contact us today to for a quote or bid.

At Windy City Representatives, we partner with premier HVAC equipment providers to help you design the best HVAC system for your building or facility’s needs and budget. 

Contact us today for a quote or bid.
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