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

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.