Performance of a CO₂-based demand controlled dual core energy recovery ventilation system for northern housing experiencing varying occupancy

Construction Research Centre, National Research Council Canada, Ottawa, Ontario Canada

^* Corresponding author: boualem.ouazia@nrc-cnrc.gc.ca

Abstract

Indoor air quality and health are major areas of concern in northern and remote communities where homes experience varying occupancy, often overcrowding and are influenced by ventilation. Heat/energy recovery ventilators installed in the north are selected to provide required minimum ventilation rate set by ventilation standards (ASHRAE 62.2, etc.). Northern overcrowded homes become under-ventilated, leading to deteriorated IAQ, mold and health-related problems. This paper present results from a side-by-side testing of a CO₂-based demand-controlled ERV versus a constant air flows ERV, using twin houses with simulated occupancies. The control strategy was based on the difference in CO₂-concentration between exhaust/return air from the house and outdoor air. The implemented strategy based on a CO₂ sensor network connected with an ERV continuously exhausting stale air from kitchen and bathrooms was simple and efficient in adjusting ventilation rate based on occupancy rate. The CO₂-based demand-controlled ERV provided a much better control of indoor CO₂ concentrations in the main floor and master bedroom, and with lower CO₂ concentrations in bedrooms during night time, compared to the reference house with concentrations exceeding 2000 ppm. However, the CO₂-based demand-controlled ERV had higher power consumption than conventional ERV with constant air flows.