High Performing Buildings - Spring 2009 - (Page 21) energy performance monthly total energy consumption for the proposed, reference and actual buildings the dedicated outdoor air system supplies the main HVAC system with dehumidified air. Central energy Plant The central energy plant is made up of energy producers consisting of three HFC-based chillers (one watercooled and two air-cooled) and two gas-fired hot water boilers, and energy consumers, such as the HVAC systems and the radiant slabs. Additionally, the plant is connected to a geothermal heat exchanger and a solid (sandbased) thermal energy storage system that act as either energy producers or consumers, depending on their use. At all times, the water-cooled chiller produces chilled water and low-temperature heating water, acting as a heat pump. The internal zones need chilled water all year. During the heating season, the plant recovers the heat rejected by the water-cooled chiller to produce low-temperature heating water for the perimeter zones and to treat the influence the lower surface, exposed to the level below. To compensate for the high thermal inertia and to respond to the conditions of the different spaces, the slab is zoned and controlled in such a way to ensure a base cooling capacity (internal zones and summertime for perimeter zones), using the underfloor ventilation to supply additional cooling as required due to space usage and type. During wintertime, perimeter zones are heated high enough to maintain indoor conditions without heat gains, while the underfloor system recools as needed in response to the internal loads. The temperature of the perimeter zone slabs vary seasonally, while indoor zone slabs are maintained at constant temperature all year. Special attention was needed for the use of a cold surface for cooling due to the risk of condensation. The success of such installations lies in the control of the humidity level in the spaces and a proper temperature of the cold surface with respect to the space due to the risks of condensation. To control the humidity level, Photo © Pageau morel 5x12 boreholes were drilled into the rock bed after excavation and before foundation work began. Each U-tube exiting the ground was located and protected by a pair of concrete blocks. The s p r ifoundry façade g H P wasfkept m i n g afteri the i n g s old n g 2 0 0 9 H i (right) e r o r upright B u l d existing buildings were demolished. 21
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.