Heat recovery systems re-use excess energy generated from equipment, lights, process energy, or people. Re-using this otherwise-wasted heat as an energy source can significantly reduce a lab’s cooling, heating, and humidification requirements. In labs, this typically entails capturing the cooling from the exhaust air for the incoming air.

At the Nidus Center, which includes 20,000 square feet of wet and dry labs and 24 lab modules, an “extract air” system separates general lab exhaust from fume hood exhaust. Rich Janis, president of William Tao & Associates, engineered that system using high-efficiency energy recovery wheels. Yet he doesn’t recommend using heat recovery wheels for fume exhaust due to the potential for corrosion and recirculation of pollutants. “But wheels can be used for general lab exhaust. Enthalpy wheels recover more than 50% of non-fume waste heat, recycling exhaust air from offices as fresh air in the labs.”

At Emory’s Whitehead Research Building, the energy recovery system includes four enthalpy wheels, each 20 feet in diameter, in the mechanical penthouse. The wheels use air exhausted from the facility to preheat outside air in the winter and to precool outside air in the summer. This system cost Emory about $450,000 to install, but has cut its estimated annual heating and cooling costs by $106,000. And it will save the university about $1 million in the decade that follows.

S.C. Johnson’s lab and office building also conserves energy through the use of a heat recovery wheel. The heat recovery wheel recovers both sensible (temperature) and latent (moisture) energy, with four levels of protection against cross-contamination, including a three-angstrom molecular sieve desiccant coating. All the air except the fume hood exhaust passes through this heat wheel. Because it allows for transfer of moisture as well as heat, greater quantities of outside air can be provided without sacrificing efficiency. The system is reliable, easy to maintain, and cost effective -- and it provides good humidity control.