FUNDAMENTALS OF RESOURCE-EFFICIENT HVAC DESIGN

No single mechanical system fits all of the needs of a building in a particular climate zone, let alone a high-performance building. However, high-performance buildings have mechanical systems that consider the fundamentals of energy- and resource-efficient HVAC design, such as:

• Heat flow through building elements is examined via computer economic analyses, and building loads are reduced as much as possible. This ensures that mechanical-system size is reduced.

• Natural-energy flows, such as passive solar heating, daylighting, natural ventilation, and occupant-generated heat, are exploited.

• Internal loads are reduced through daylighting integration and the use of Energy Star-labeled equipment.

• The building is divided into thermal zones that are served by mechanical systems. This results in higher system controllability, resulting in greater occupant satisfaction.

• Mechanical systems are decentralized, or multiple-zone control is used within larger units.

• System losses, such as those in ducts and piping, are reduced.

• Air systems use low-pressure ductwork.

• Premium-efficiency motors are employed.

• Variable-load fan systems are used, and part-load performance is considered in equipment selection to maximize operating efficiency.

• Occupancy-based controls, including time-of-use and demand-based control, are used in areas that have varying and high-occupancy loads.

• Energy recovery is used for ventilation air.

• Electric loads are shifted or curtailed during peak demand periods.

• High-efficiency mechanical systems are used.

• Testing, adjusting, and balancing are specified and performed completely.

• Noise and vibration control is provided for mechanical systems and commissioned.

• An operations-and-maintenance program is established and documented.

• Provisions are made for proper performance monitoring and verification.