Laboratory performance factors are the most difficult to quantify. This important group includes: HVAC system diversity; laboratory heat gain from process loads; fume hood user energy-efficiency practices; maintenance costs; system failure rate; and heat recovery and free-cooling effectiveness. [Lacey, 1993]
To calculate the LCC economics of a VAV system, a diversity value is necessary. Diversity values can range from 0.02 to 0.60. HVAC system diversity is reviewed extensively later in this chapter. [Lacey, 1993]
Process heat gain from laboratory equipment is in many facilities the major source of heat gain but is difficult to define. Little information has been published that provides guidance on this subject to energy engineers. [Lacey, 1993]
Good energy and safety practice mandates that fume hood sashes be lowered when hoods are in use and be closed when hoods are not in use. An off-hour setback that allows the ventilation system to go into a reduced volume mode when labs are not occupied is also a part of a complete energy use program. [Saunders, 1993]
