Revised standard helps gain 30% savings over 2004 Standard

The requirements of the revised Energy Standard ANSI/ASHRAE/IES Standard 90.1-2013, Energy Standard for Buildings Except Low-Rise Residential Buildings, published by ASHRAE and IES in October 2013 will result in buildings that could achieve six to eight per cent more efficiency than buildings built to the 2010 standard.

Highlighting this in a news release, ASHRAE revealed that Pacific Northwest National Laboratories (PNNL), in support of the Department of Energy’s Building Energy Codes Program, conducted the energy savings analysis on 110 addenda included in the standard. It gave the following details:

• PNNL’s analysis shows that the site and energy cost savings are 37.7% and 37.8%, respectively, by using the 2004 standard as baseline for only the regulated loads.
• For the entire building energy consumptions, national aggregated site energy savings a¬re 29.5% and energy cost savings are 29.0%, it added.
• On a nationally aggregated level, building-type energy savings range from 19.3% to 51.9% and energy-cost savings from 18.6 to 50.6%.

These figures reportedly include energy use and cost from the entire building energy consumptions and plug and process loads.

Throwing light on the analysis work performed by a team from Pacific Northwest National Laboratories, ASHRAE said that 16 different building prototypes were modelled in 17 different climate locations for a total of 272 building types and climate zone combinations. Energy reduction was reportedly achieved through 33 addenda related to major changes to requirements regarding building envelope, lighting, mechanical and the energy cost budget, the most significant being:

• Building Envelope: Opaque elements and fenestration requirements have been revised to increase stringency while maintaining a reasonable level of cost-effectiveness. Opaque and fenestration assemblies in Tables 5.5-1 through 5.5-8 are revised in most climates. These changes include:
  • Criteria requiring double glazed fenestration in many climates
  • Minimum visible transmittance/solar heat gain coefficient (VT/SHGC) ratio to enable good daylighting with minimum solar gain, while not restricting triple- and quadruple-glazing.
  • Simplification of the skylighting criteria.
• Lighting: Changes include improvements to daylighting and daylighting controls, space-by-space lighting power density limits, thresholds for toplighting and revised controls requirements and format.
• Mechanical: Equipment efficiencies are increased for heat pumps, packaged terminal air conditioners, single package vertical heat pumps, air conditioners and evaporative condensers. Also, fan efficiency requirements are introduced for the first time.
• Additional provisions address commercial refrigeration equipment, improved controls on heat rejection and boiler equipment, requirements for expanded use of energy recovery, small motor efficiencies and fan power control and credits.
• Control revision requirements have been added to the standard, such as direct digital controls in many applications.
• Another important change is the first alternate compliance path in Chapter 6. Section 6.6 was added to the 2010 edition to provide a location for alternate methods of compliance with the standard.  The first such alternate path has been developed for computer room systems and was formulated with the assistance of ASHRAE technical committee 9.9, Mission Critical Facilities, Data Centers, Technology Spaces and Electronic Equipment. This path uses the Power Usage Effectiveness (PUE) metric established by the datacom industry.

Commenting on the revised standard, William Bahnfleth, ASHRAE President, said, “As we approach the 40th anniversary of the publication of the standard, these new savings underscore Standard 90.1’s key role in promoting energy efficiency in buildings in the United States by establishing successively more stringent – but cost effective – minimum requirements, and we look forward to further advances in future revisions.”

Rita Harrold, Director of Technology, added: “The Illuminating Engineering Society of North America (IES) has provided technical support on lighting related requirements in each iteration of the standard since 1975. IES continued that role in developing the energy efficiency provisions in the 2013 standard through modified LPDs and additional daylighting and controls strategies. The challenge to achieve higher energy efficiencies increases with each version of the standard and begins anew as we address targets for the 2016 edition.”