Challenge: Due to the corrosive and toxic nature of the fume-hood exhaust system, it was a challenge to match specific heat recovery systems based on the application and life-cycle analysis.
Solution: A run-around style loop was used to transfer heat out of the exhaust stream to preheat incoming outside air. A higher efficiency heat pipe system was used to recover heat from the laboratory general exhaust stream. Rather than waste the heat from the chilled glycol system in the wintertime, outside air serving the ventilation units is initially drawn through a parallel duct with a coil that functions as a dry cooler for the chilled glycol system. The outside air is preheated and then routed back to the ventilation units for use in the building. Bypasses were installed to prevent overheating.