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that in the long-term, HRVs are cost-effective because energy savings more than offset their higher initial capital costs. An energy recovery ventilator (ERV) is a device designed to recover heat and moisture from the outgoing airstream and transfer it to the incoming outdoor air. In the winter, this not only reduces heating costs, but it also helps prevent the indoor house air from becoming drier than it otherwise would be due to continuous ventilation. In the summer, the ERV helps reduce the temperature and humidity of the incoming outdoor air, bring down cooling costs and increase comfort.
Plate heat exchangers—In plate heat exchangers, outdoor air and indoor exhaust air flow through channels in alternate, adjacent plates (Figure 163). During the winter, heat is passed from the warm exhaust air to the incoming outside air. ERV plate heat exchangers transfer both heat and moisture while HRV plate heat exchangers transfer heat only. The latter must be connected to the plumbing system or floor drain since the exchange of heat between adjacent plates causes moisture from the indoor exhaust air to condense and drip out of the heat recovery core where it must be collected and drained.
163 Common types of heat recovery ventilators Plate heat exchanger exhaust to outside
exhaust fan
plate heat exchanger fresh air to house
stale air from house air supply from outside
supply fan
condensate drain
Wheel heat exchanger exhaust to outside
exhaust fan
heat wheel stale air from house
fresh air to house
air supply from outside
supply fan