Performance of a dual core energy recovery ventilation system for use in Arctic housing

The extremes of arctic climate pose severe challenges on housing ventilation systems, energy consumption and demand for space heating for northern remote community residential buildings. As a part of the overall effort to reduce space heating requirements, dwellings are built air tight to reduce heat losses. However, airtight homes require energy efficient and effective ventilation systems to maintain acceptable indoor air quality and comfort, and to protect the building envelope from moisture damage. Heat and energy recovery ventilation systems are used to reduce energy consumption and improve the ventilation rate of housing in Canada’s north. Their performance achieved to date has been inadequate due to equipment failures (freezing of cores, partial/full blockage of air flow passages, etc.). This paper presents a rigorous investigation on the performance of a novel dual core energy recovery unit designed for housing in harsh cold climates. The methodology included (1) lab evaluation using climatic chambers to simulate indoor and outdoor conditions identified by certification standard and those identified in the Arctic, (2) side-by-side testing using twin houses to compare whole building performance between a house equipped with a single core ERV and a house equipped with a dual core energy recovery system, then (3) extended monitoring of the dual core technology in Nunavut for proven long-term performance and resilience. This paper discusses the apparent sensible and total efficiencies, flow characteristics, supply air temperature to indoor, frosting occurrence and its impact on the performance of the dual core unit. The dual core technology was found to be more frost-tolerant, capable of withstanding a temperature of down to -40°C without deteriorating its thermal performance, was also found to be able to provide continuous delivery of outdoor air to the space even at very low outdoor temperatures and was able to supply air to the indoor at temperature warmer than 15°C with outdoor temperature of -40°C. The dual core ERV system had higher apparent sensible effectiveness (82% compared to 70% for the single core ERV), a difference of 10 percentage points, and had higher calculated apparent total effectiveness (73% compared to 68%), a difference of 5 percentage points). A house with a dual core ERV showed a significant heating and ventilation energy saving of 6.2% over a week testing period in winter 2017. The technology has been deployed in the Nunavut for extended monitoring since June 2017 for proven performance, resilience and durability in harsh arctic climate.