Energy Recovery in Minnesota Commercial and Institutional Buildings: Expectations and Performance

ERV-report.pngBackground

Energy recovery ventilation (ERV) systems exchange heat and/or moisture between the outgoing exhaust air and the incoming outdoor (ventilation) air. These air-to-air ERVs are incorporated into mechanical ventilation systems and have the ability to reduce the resulting heating and cooling loads. When operating according to design, it is possible for ERVs to use 10 to 100 times less energy than conventional heating and cooling systems, resulting in up to 80% energy savings on ventilation loads.

Despite their substantial energy efficiency potential, studies on as operated energy recovery units are few and expectations have been tempered by real world observations — there is anecdotal evidence suggesting that as-operated performance of ERVs may not live up to expectations.

This project investigated the expectations and the operating performance of ERV units in Minnesota commercial and institutional buildings. The project team used available data to characterize commercial and institutional ERVs in Minnesota and then monitored the performance of representative ERV systems, identified and rectified problems that diminish ERV performance, and documented the energy use and costs associated with under-performing ERVs. 

The specific objectives were to:

  1. Characterize ERVs in Minnesota commercial and institutional buildings
  2. Study a representative sample ERVs in detail
  3. Characterize and improve ERV performance

Full Report (PDF)
Energy Recovery in Minnesota Commercial and Institutional Buildings: Expectations and Performance

Resource
A Quick Guide to Validate Air-to-Air Exhaust Energy Recovery‚Äč

This project supported in part by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program.