HVAC System Requirements for LEED compliance
HVAC System: The equipment, distribution systems, and terminals that provide, either collectively or individually, the processes of heating, ventilating, or air conditioning to a building or portion of a building.
Energy efficiency in a green building starts with a focus on design that reduces overall energy needs, such as building orientation and glazing selection, and the choice of climate-appropriate building materials. Strategies such as passive heating and cooling, natural ventilation, and high-efficiency HVAC systems partnered with smart controls further reduce a building’s energy use. The generation of renewable energy on the project site or the purchase of green power allows portions of the remaining energy consumption to be met with non–fossil fuel energy, lowering
the demand for traditional sources.
LEED EQ Credit: Min Energy Performance
To reduce the environmental and economic harms of excessive energy
use by achieving a minimum level of energy efficiency for the building
and its systems.
Option 1: Whole Building performance
Demonstrate an improvement of 5% for new construction, 3% for major renovations, or 2% for core and shell projects in the proposed building performance rating compared with the baseline building performance rating. Calculate the baseline building performance according to ANSI/ASHRAE/IESNA Standard 90.1–2010, Appendix G, with errata (or a USGBC-approved equivalent standard for projects outside the U.S.), using a simulation model.
The proposed design must meet the following criteria:
- compliance with the mandatory provisions of ANSI/ASHRAE/IESNA Standard 90.1–2010, with errata (or a USGBC-approved equivalent standard for projects outside the U.S.);
- inclusion of all energy consumption and costs within and associated with the building project; and
- comparison against a baseline building that complies with Standard 90.1–2010, Appendix G, with errata (or a USGBC-approved equivalent standard for projects outside the U.S.).
As Per ASHRAE 90.1
Performance Rating Method Scope. This building performance rating method is a modification of the Energy Cost Budget (ECB) Method in Section 11 and is intended for use in rating the energy efficiency of building designs that exceed the requirements of this standard.
Performance Rating. The improved performance of the proposed building design is calculated in accordance with provisions of this appendix using the following formula:
Following are HVAC system requirements for energy modeling for Basecase as well as proposed case.
Full table can be accessed in ASHRAE 90.1-Appendix G, table G3-1.
HVAC Systems as per ASHRAE 90.1
Equipment Efficiencies. All HVAC equipment in the baseline building design shall be modeled at the minimum efficiency levels, both part load and full load, in accordance with Section 6.4.Where efficiency ratings, such as IEER and ICOP, include fan energy, the descriptor shall be broken down into its components so that supply fan energy can be modeled separately.
Equipment Capacities. The equipment capacities (i.e. system coil capacities) for the baseline building design shall be based on sizing runs for each orientation (per Table G3.1, No. 5a) and shall be oversized by 15% for cooling and 25% for heating, i.e., the ratio between the capacities used in the annual simulations and the capacities determined by the sizing runs shall be 1.15 for cooling and 1.25 for heating.