A heat wheel is a rotating apparatus generally used to reduce the energy consumed by air-conditioning equipment in humid locations. It functions as a rotary heat exchanger, which means that it continually attempts to achieve thermal equilibrium. The device operates by having a warm air stream and a cold exhaust air stream flowing through its opposing halves, making use of these counter-streams to cool hot air and to heat cold air.
Geothermal Energy Systems in Atlanta – A Heat Wheel.
The physical structure of a heat wheel resembles an aluminum disk and an exhaust fan placed in the middle of two air ducts. One air duct has warm outdoor air passing through it, and the other duct releases cold air chilled by the exhaust fan. Filters also are in place to ensure that the air entering and exiting the apparatus are clean.
The heat wheel accomplishes thermal equilibrium by first being chilled by cool air directed by the exhaust fan. When its cold portion rotates to encounter the warm outdoor air stream, it then absorbs heat from the air. As the device absorbs warmth from the air, the outdoor air stream temperature consequently drops. When the wheel rotates back to its starting point, it then sends the absorbed heat into the cold exhaust air while simultaneously being once more chilled.
Solar Water Heating Systems in Atlanta – The Second Law of Thermodynamics.
The concept of the heat wheel operates on the second law of thermodynamics, wherein heat will always move from areas of higher temperature to areas of lower temperature. The apparatus, by merely rotating, enables heat to come into contact with cold air and thus accordingly transfer. This balances out the temperature in two adjacent locations, cooling hot air and warming cold air.
Mini Split AC in the USA 