High Performing Buildings - Spring 2008 - (Page 64)

N AT U R A L V E N T I L AT I O N Natural ventilation is used whenever possible. A manual override switch allows for a majority of the HVAC equipment to be turned off at once. Windows can be opened for natural ventilation and corresponding energy savings. Within the administration area, a control light tied to outdoor temperature and humidity turns from red to green when conditions are correct for natural ventilation, indicating to the staff to switch off the mechanical system and open the windows. Natural ventilation is supplemented with an exhaust fan positioned near the peak of the roof, providing added comfort when required without engaging the air-conditioning system. This effective use of resources results in a building with very low energy consumption. Heating and cooling is provided by 30 ton and 10 ton water-to-water heat pumps. The heat pumps provide warm and chilled water to fan coil units located near each space. The heat pumps also use the well water on the way to the kettle pond or water sprayground as a heat sink. Because the well water is always 50°F–55°F, cooling is efficient. The energy efficiency rating is greater than 20. The heating mode is kept efficient by minimizing the hot water system temperatures. Multirow heating coils extract heat from the lower temperature (110–120°F) circulating water. A 100% outdoor ventilation unit provides ventilation air to distributed fan coil units. The unit is equipped with free heating and cooling coils that precondition ventilation air using nearly constant 50°F well water (indirectly, through plate and frame heat exchangers) which is then directed either to the kettle pond or the water sprayground. The free heating and cooling coils work in unison with a variable speed heat recovery wheel. Building exhaust/relief air is ducted through the wheel, recovering energy otherwise exhausted to the outside. Between the free heating and cooling coils and energy recovery wheel, the building ventilation air is almost entirely preconditioned without having to use mechanical heating or cooling. An additional cooling coil is provided in the unit for occasional building dehumidification. Occupancy sensors minimize ventilation airflow rates and automatically set back the space setpoint temperatures when the associated room is unoccupied. Additionally, a variable speed supply fan in the ventilation unit minimizes the amount of fan energy required to deliver the ventilation air. 64 HIGH PERFORMING BUILDINGS Spring 2008 © SmithGroup

Table of Contents for the Digital Edition of High Performing Buildings - Spring 2008

High Performing Buildings - Spring 2008
Daikin AC (Americas)
Contents
Seattle City Hall
SEMCO
3M Energy & Advanced Materials
Price
Sofame Technologies Inc.
Sweetwater Creek Visitor Center
ASHRAE Certification
Greenheck
Daylighting Strategies That Maximize Benefits
Energy Conservatory, The
ASHRAE e-learning
Ecobuild America
CTG Energetics, Inc.
Cambridge City Hall Annex
Tate Access Floors, Inc
Air-Conditioning, Heating, & Refrigeration Institute
31 Tannery Project
Building Owners & Managers Institute
Indian Springs Discovery Center
International Facility Management Association
ASHRAE Healthcare
Fulton Companies, The
AAON, Inc.

High Performing Buildings - Spring 2008