In evaluating HVAC system design options, engineers must analyze the initial cost as well as the cost of maintaining and operating a building. Increasingly however, a ‘third side’ to this coin requires evaluation – the economic impact that HVAC design options have on user productivity.
“Natural stratification of warm water above cold water is ineffective in storage tanks at water temperatures below 70 F. Separation of chilled return water is essential to maintain the storage energy potential. This is accomplished using a three full/one empty tank system.”
“Water is cooled by evaporative coolers at night and stored in the underground tanks to be used for air conditioning the following day, minimizing the use of a chiller. Cooling coils operate at 55 F entering chilled water temperature.” “The chillers, pump, and evaporative coolers, when operating during the day, require 273 KW input at coefficient of performance (COP) of 3.9, while the night ‘free’ cooling cycle requires only 48 KW at COP of 22.”
“Rosenfeld identified key elements that can mean lower initial construction cost and reduced energy consumption over the life of the building.”
“The energy conserving features had to be cost effective, yet not at the expense of a comfortable office environment.”
“The engineers met this challenge through a combination of simple but effective use of efficient and innovative mechanical system design. This resulted in a three time Energy Conservation Award Winning Building which is air conditioned without the use of a chiller, even when the outside air temperature exceeds 100 degrees F.”
Shlomo Rosenfeld