I live in northeast Tennessee were soon the temperature will start dropping. I'm utilizing a floating raft system comprising deep water channels (DWC) in a greenhouse and have been thinking about options to maintain optimum air and water temperatures during the winter. I'm running 110 liter per hour air pump with 12 air stones distributed throughout a 720 gal channels. Today, I thought about introducing warm air (e.g., at 100F) into the air pump inlet and wondered if the warm bubbles introduced to the water might provide a means for temperature control to both the water (roots) and air (leaves). To facilitate holding the heat in the air, I can add catipiller tunnels to the DWC channels overlaid with clear plastic. Any thoughts as to whether this has been tried, might work, and any thoughts wrt design? An option I thought worth considering for heating the air would be to require the air entering the air pump to pass through a heated pipe.
Unlikely to work, as air holds very little heat energy (the technical term is heat capacity).