Rating System

LEED BD+C: New Construction, LEED BD+C: Schools

Rating System Version

v2 - LEED 2.2, v2 - Schools 2007

Inquiry

Our project, a data center located in Nebraska, can be characterized as typical for a newly constructed data center in the sense that the energy used per square foot is 100 times greater than that of a modern office building. However, in an effort to increase the energy efficiency of this project, our team has implemented several strategies which will appreciably reduce the energy required to operate the cooling equipment. 1. Removing the computer room air conditioning supply fans by allowing the computer server fans to circulate all of the cooling air 2. Using waste heat from the computer room to provide all of the humidification requirements which would otherwise need to be obtained by mechanical means 3. Using optimized direct evaporative cooling and enthalpy controls for the computer room that maximizes and extends the use of outdoor air cooling. This allows for chillers and cooling towers to remain completely off for five months per year 4. Implementing Cold Aisle supply air containment in the computer room. 5. Elevating cooling supply air temperature to the data center - 75F 6. Elevating chilled water supply temperature - 55F We would like to use the LEED v2.2 Exceptional Calculation methodology (ASHRAE Std. 90.1 G2.5) to quantify the process loads reduction generated by our design using the above strategies. We would like to propose that, for the baseline, we use ASHRAE 90.1 2007 as outlined in the Environmental Performance Criteria (EPC) Guide for New Data Centers, DRAFT based on LEED NC 2.2, 03 September 2008. The EPC guide was the result of a collaborative effort that included a diverse group of participants and organizations, including ASHRAE TC9.9, The Green Grid, The Uptime Institute, 24x7, the European Commission, the Critical Facilities Roundtable, and the Silicon Valley Leadership Group. ASHRAE 90.1 2007 more specifically quantifies the energy breakdown of components in data centers including computer hardware, mechanical systems that support computer equipment, and humidification and dehumidification, and our team feels that it would an appropriate baseline for this calculation. We would still use the Building Performance Rating method to calculate our projected savings as outlined in Appendix G of ASHRAE 2007. We would also assume that the point interpolations given in the EPC Guide for New Data Centers (10-34 points possible, written for LEED 2009) would NOT be used, and we would be using the standard point interpolation tables found in LEED v2.2 EAc1 Optimize Energy Performance (1-10 points possible) as required by LEED v2.2. We request clarification on two items: 1. Is the approach we have outlined acceptable for showing compliance with EAc1 Optimize Energy Performance? 2. If it is acceptable, would we be required to use the ASHRAE 90.1 2007 standard in the calculation of EAc2 Minimum Energy Performance and EAc3 Renewable Energy (which would obviously directly relate to the EAc1 credit)?