ABSTRACT
A high-performance building (under whatever name it may be described as-green, net-zeroenergy, carbon-neutral) will necessarily involve an energy-efficient climate control system. The most energy efficient climate control options are those based upon passive heating and cooling principles. Unfortunately, passive climate control systems are not effective in all climates and/or in all building types.When a passive heating or cooling approach cannot meet the owner’s project requirements (sometimes described as design intent and criteria) an active approach to climate control will likely be considered and implemented. The owner’s project requirements (abbreviated OPR in building commissioning documents)
comprise a definitive statement of those project outcomes that will be considered important to defining a successful project. Such pre-defined requirements, which will shape design, construction, and operation decisions, commonly include targets for energy use (such as an EUI, energy utilization intensity, value), acceptable indoor air quality conditions, expected thermal comfort parameters, desired operations and maintenance procedures, and very often a desired green building rating level. Failure to clearly define what a successful project must accomplish places the design team at a distinct disadvantage and often leaves the owner dissatisfied with project outcomes. Active climate control systems are collectively termed HVAC (heating, ventilating and air-
conditioning) systems. In larger buildings requiring active climate control, owner requirements have historically led to inclusion of a system thatmeets the definition of air-conditioning promoted by theAmerican Society of Heating, Refrigerating andAir-Conditioning Engineers (ASHRAE) – namely a system that can simultaneously control air temperature, relative humidity, air distribution, and air quality. An “AC” system, by definition, includes the “H” and “V” aspects of HVAC.
