To maintain healthy indoor air quality (IAQ) and meet building codes, buildings must have fresh, outdoor air, also called ventilation air.
This requirement can be expensive since the air must be heated or cooled and then exhausted to make room for more ventilation air. Energy recovery systems recover thermal energy from the conditioned exhaust air, helping building owners and operators save on energy costs.
There are many types of energy recovery systems but the most commonly used are rotating wheels, plates, heat pipes and runaround loops. CenterPoint Energy recommends working closely with a design engineer to evaluate and design a system that is the most efficient and effective for your operation.
Energy recovery wheels can be used in heating, ventilating and air conditioning applications. This chart summarizes the pros and cons of the most common types.
| Fixed plate | Rotary wheel | Heat pipe | Runaround loop | |
| Cross leakage | 0 to 5% | .5 to 10% | Minimal | 0% |
| Heat transfer | 50 to 80% | 50 to 85% | 45 to 65% | 55 to 65% |
| Capacity control | Bypass ducting | Speed control Bypass ducting | Tilt angle | Speed |
| CFM range | >50 | >50 | >100 | >100 |
| Limitations | Large size at high CFM rates | Cross leakage | High air side pressure drop | Requires accurate sizing |
| Advantages | No moving parts | Compact large sizes | No moving parts | Separate supply and |
