S06 - Session O1 - Design, development, and performance testing of a novel porous concrete energy exchanger for agricultural buildings.

Authors: Md Sazan Rahman *, Jérôme Trudel-Brais, Sarah MacPherson, Mark Lefsrud

Energy recovery in ventilation is one of the most challenging tasks in indoor framing and greenhouse production. All traditional technologies can recover most sensible heat, but significant amounts of latent heat from outgoing air are lost. The energy wheel or other direct energy recovering technologies are not used in greenhouses as the supply air is normally ensured as dry ( < 50% of relative humidity) for any outdoor weather conditions. In this study, a novel energy exchanger was designed and developed by using three porous concrete wheels that can recover both sensible and latent heat from the outgoing airstream, and transfer this heat to the supply airstream continuously. The heat exchanger was made of three 30% porous concrete rotary wheels (30 cm diameter and 2.5 cm thick) that were placed 30 cm apart from each other in a single shaft. The body frame was made of plywood and sheet metal connectors to flow air using four air blowers. The unit was experimentally investigated for both heat and energy transfer performance with different inlet air temperatures (from 5 ºC to 70 ºC), relative humidity (0n95%), and wheel speed (0n30 rpm). Experimental results indicate that the porous concrete heat exchanger can provide continuous air supply at setpoint temperature during northern hemisphere winter and spring seasons (Montreal, Canada) by recovering sensible and latent heat from the outgoing air. This eco-friendly energy exchanger could start new discussions surrounding energy exchanger technologies that reduce the carbon footprint of traditional energy exchanger materials by providing high sensible and latent heat recovering capacity.