Optimal Operation and Control of Heat Recovery System in the Laboratory Air Handling Unit (LAHU) System

Optimal operation and control of heat recovery in the Laboratory Air Handling Unit (LAHU) system differs from the optimal control and operation schedule used in 100% outside air AHU. In the LAHU system, economizers can be used in both the office section and the laboratory section. An optimal operation and control schedule for the heat recovery systems has been developed by using the first derivative test for local extreme values to minimize the total thermal energy consumption. The schedule turns off the heat recovery system when the outside air temperature is higher than the LAHU free cooling temperature, which is much lower than the AHU discharge air temperature. The optimal schedule actually also reduces the electricity consumption of heat recovery water circulation pump and improves room relative humidity condition. The optimal operation and control schedule developed in the paper also applies to AHUs where economizer is used. The study also found that a heat recovery system may not be necessary for LAHUs under certain conditions.