July 7, 2011: Changes to Fan Efficiency Requirements Proposed for ASHRAE Energy Standard
“Currently, the standard only regulates fan power at the system design level,” said Ned Heminger, chair of the Standard 90.1’s Mechanical Subcommittee. “In other words, the amount of fan power allowed in a system is based on the system maximum airflow rate. However, the standard does not set requirements for the manufacturers of fans. As a result, there is a wide range of fan efficiencies available on the market. When the current prescriptive requirements were set for fan power, the fan efficiency chosen was achievable by most fans currently available at the time. Developing a fan efficiency metric that applies to the manufacturing of fans will encourage the advancement of efficient fan design. As fan efficiency increases, fan power needs decrease. This allows the standard to improve on the fan power limits in the future. The proposed addendum has set the initial efficiency bar at a level that is achieved by most fans, with assistance from ASHRAE technical committee 5.1, Fan Design and Application. The intention is to work with TC 5.1 to increase the efficiency requirements for fans in future versions of the standard.”
He also noted that the proposed addendum was issued utilizing ASHRAE’s advisory public review option available to solicit feedback from the industry. This was done at the recommendation of committee members to better understand the impact to the industry as the standard is proposing compliance with a new certification standard. The committee noted that it recognizes the importance of constructive feedback from industry members and looks forward to hearing their suggestions.
Unlike comments received through ASHRAE’s formal call for public comments process, comments received on advisory public reviews are considered opportunities for constructive input from interested and materially affected parties in the development of proposed language that will be issued for official public review and need not be resolved or formally acted on by the project committee.
Addendum u is open for advisory public review until July 25, 2011.
In addition, other addenda to this standard open for review until July 10, 2011 are:
• Addendum l fixes a mistake in Section 126.96.36.199.2 for fan brake horsepower methodology.
• Addendum n clarifies that the total lumens/Watts for the entire elevator cab is being required to meet the efficiency requirement, but that it is not required that each individual light source must comply.
• Addendum o updates the fenestration air leakage provisions to clarify the requirements for glazed sectional garage doors. A new definition for sectional garage doors is also added.
• Addendum s – Large amounts of fan energy can be wasted when zones report incorrect information to the control system, which causes the supply fan speed to increase, often to maximum speed. This addendum requires additional safeguards to prevent this, and for non-DDC systems requires location of sensors in areas that do not require high setpoints.
• Addendum t corrects the reference to the proper section for damper leakage in 188.8.131.52.4 (Dampers). This addendum also clarifies that the damper leakage requirements in 184.108.40.206.3 (Damper Leakage) and as defined in Table 220.127.116.11.3 (Maximum damper leakage) applies to the return air dampers used in economizers.
Additional proposed addenda open for public review until July 25, 2011 are:
• Addendum a updates the test procedure references for product information in the Tables in Section 10.8 (product information), and also adds a normative reference in Chapter 12. This will make the table references more consistent with other equipment tables (and other test procedure references).
• Addendum cj modifies Appendix G (Performance Rating Method) to change the requirements for economizers and how they are modeled in computer rooms.
• Addendum m adds power density and control requirements to capture additional savings; adds a needed exemption for practical application, includes submittal requirements; and changes control credits to apply only to lamps in multi-lamp fixtures that are controlled.
• Addendum p adds a reference to CRRC-1 for cool roofs testing requirements.
• Addendum q updates the ASHRAE dynamic glazing definition to match the National Fenestration Rating Council dynamic glazing definition.
• Addendum r clarifies the intent of the committee and relocates all wording related to thermostat and humidity schedules to the Schedules section of Table G3.1 for greater ease of use.
• Addendum v requires that the controlled receptacles be appropriately identified so that users can clearly distinguish between controlled and non-controlled receptacles.
• Addendum w clarifies the credits for renewable energy and purchased energy in Section 11 (Energy Cost Budget Method) and Appendix G (Performance Rating Method).
For more information and to comment, visit www.ashrae.org/publicreviews.
Publication date: 07/04/2011