Rating System

LEED BD+C: New Construction, LEED BD+C: New Construction, LEED BD+C: Schools, LEED BD+C: Schools, LEED BD+C: Core and Shell, LEED BD+C: Core and Shell

Rating System Version

v2 - LEED 2.2, v3 - LEED 2009, v2 - Schools 2007, v3 - LEED 2009, v2 - LEED 2.0, v3 - LEED 2009

Inquiry

Station Lands - Phase 1 - EPCOR Tower: CIR for Energy and Atmosphere: Optimize Energy Performance (Credit 1) This CIR pertains to the appropriate Baseline system choice for a heated parkade, as per ASHRAE 90.1-2004. The building in question is a 29-storey office building with a 4-level underground parkade located in Climate Zone 7 (very cold, with \'5000-7000 annual heating degree days\'). The parkade is 26,500 sq.m. and requires 5,000 kW of heating capacity to heat the outdoor air (to ventilate the parkade) to above freezing point on the coldest day. The parkade will be heated to 4 \'degC\' in winter, and will not be cooled. In ASHRAE 90.1-2004, 189 W/sq.m. of heating output classifies this as a heated space according to Table 3.1 Heated Space Criteria, and the size of 26,500 sq.m. classifies it as requiring a System 7 - VAV w/ Reheat system in the Baseline according to Table G3.1.1A Baseline HVAC System Types. However, the parkade is a single thermal zone (earth on all walls and underneath, and a fully conditioned office space above), which makes a system choice of VAV seem inappropriate. The Proposed Design is a Built-up Single Zone system with natural gas furnace heat, and no cooling. Guidance from ASHRAE Technical personnel has been that "the Baseline is to provide a simpler system than the Proposed design." Question: In accordance with the actual thermal zoning of the parkade and the guideline that it is to be, generally, an equally simple or more simple system than the Proposed Design, should the Baseline system be a single zone system? If not, what is a proper system choice for the parkade in the Baseline case?