Sustainable laboratory evaluations: Optimized fume-hood- intensive ventilation and energy efficiency without compromising occupational safety and comfort

Abstract

Fume-hood-intensive laboratories consume enormous amounts of energy, especially in hot and humid climates, where the ambient air is dehumidified and cooled before it is brought into the building. Hence, excessive ventilation beyond what is needed to maintain a safe and comfortable laboratory environment is costly. This study aims to explore potential alternatives to conventional ventilation strategies in chemistry laboratories with high fume hood density, for optimizing energy efficiency without compromising safety and comfort during occupied periods. Due to the limited floor areas, these laboratories are increasingly used in high-density cities, like Singapore. First of all, the effects of conventional ventilation strategies and their alternatives on air quality and thermal comfort conditions are simulated in a target laboratory under 1) small chemical spills, 2) large chemical spills, and 3) large heat gains. Secondly, based on the evaluation of the simulation results, optimized ventilation strategies, compared with conventional ones, are explored. Thirdly, the potential energy savings of these optimized strategies are estimated. The findings suggest that it is feasible to optimize laboratory ventilation by better coordinating the local and general exhausts, while their coordination strategies vary in different scenarios. With the optimized strategies in the target laboratory, the conventional set points of 12 and 15 ACH (air change per hour) in normal (occupied) and emergency scenarios can drop to 8 ACH. Meanwhile, the corresponding hourly energy savings are up to 0.33 kWh (33.3%) and 0.58 kWh (46.7%). The findings derive a cleaner and more sustainable way to operate fume-hood-intensive laboratories. They complement the current laboratory ventilation standards, addressing the significance on better coordinating the general and local exhausts in fume-hood-intensive laboratories.