Energy Efficiency and Plant Devices
In the past, mechanical plants have been sized for 100 percent of peak load at 99 percent climatic tolerance with an additional 20 to 50 percent "start-up factor" and another 20 to 30 percent "safety factor." These days are over. "Right-sizing" a laboratory facility's mechanical plant reduces first costs and operational energy costs, reducing energy waste by 40 to 50 percent compared to conventional design practices. Two key choices help optimize the energy-efficient operation of supply systems:
·modularizing the boiler/chiller plants and air-handling systems,
·matching the plant operation to load as it varies annually.
Selecting boilers/chillers with the best efficiencies will nearly always prove cost effective; dual-temperature cooling systems should also be considered to optimize chiller operation. Free Cooling can supplant chiller operation by using installed cooling tower capacity to its fullest extent. A plate-and-frame heat exchanger acts like a "substitute chiller" to provide cooling water when the system is designed to take advantage of cool ambient temperatures.