ASHRAE Proposes Changes to Requirements for Energy-efficient Design of Buildings

Energy-savings measures related to variable air volume (VAV) and cooling towers are being proposed for an energy standard for buildings, the American Society of Heating, Refrigerating and Air-Conditioning (ASHRAE) announced on Sept. 21.

ANSI (American National Standards Institute)/ASHRAE/IESNA (Illuminating Engineering Society of North America) Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, provides minimum requirements for the energy-efficient design of buildings except low-rise residential buildings. Fourteen proposed addenda to the standard currently are open for public comment.

Under proposed addendum l, closed circuit cooling tower requirements to help reduce energy consumption would be added to the standard. The addendum would add minimum efficiency and certification requirements for both axial and centrifugal fan closed circuit cooling towers, also known as fluid coolers.

"These requirements will provide consulting engineers, system designers and contractors with guidelines for the selection of independently certified, energy-efficient closed circuit cooling towers," Mick Schwedler, chair of the 90.1 committee, said. "This change also will complement existing minimum and certification requirements for open circuit cooling towers, helping prevent confusion between the requirements for open vs. closed."

Also open for public comment is addendum n, which extends variable air volume fan requirements for large single-zone units. VAV fan control currently is required in the standard for multiple-zone systems. Extending VAV control to single-zone units would save energy by reducing fan energy consumption when space cooling loads are reduced, he said.

The change would take effect in 2012, allowing air conditioning unit manufacturers time to redesign and test their units. Manufacturers are currently redesigning to meet the 2010 phase-out of certain refrigerants.

"Utility rebate programs and other incentives should encourage wider demand for these units and help this requirement to see real savings before 2012," Schwedler said.

In addition, addendum r, which would change informative Appendix G's performance rating method into a normative appendix, is open for comment. Making the performance rating method normative, or required, would allow its adoption into advanced energy standards, such as proposed Standard 189P, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings, being developed by ASHRAE in conjunction with IESNA and the U.S. Green Building Council. Additionally, language has been changed to make Appendix G enforceable allowing adoption by model codes.

Proposed addenda are open for review until Oct. 14. To read the addenda or to comment, visit

This article originally appeared in the 09/01/2007 issue of Environmental Protection.

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