Rating System

LEED BD+C: New Construction, LEED BD+C: New Construction, LEED BD+C: Schools, LEED BD+C: Schools, LEED BD+C: Core and Shell, LEED BD+C: Core and Shell

Rating System Version

v2 - LEED 2.2, v3 - LEED 2009, v2 - Schools 2007, v3 - LEED 2009, v2 - LEED 2.0, v3 - LEED 2009

Inquiry

The project is an existing landmarked building in NYC pursuing LEED Core & Shell certification. Specifically, the building will undergo a gut rehab of all its floors. The building is currently served by four CFC chillers. To increase the energy efficiency of the building, and to obtain the two EAc1 points, the building plans to replace the CFC chillers with efficient chillers that also comply with the requirements of EAc4 Enhanced Refrigerant Management. Energy modeling projects that chiller replacement will result in $48,200/year energy cost savings. The cost of replacing chillers is high, because piping and ducting added over the years to the mechanical room are making the removal of the chillers impossible without changes to the MER. The cost of replacement including changes that would be needed for piping, controls and modifications to existing mechanical room is estimated to be 4-5 million dollars, resulting in a simple-payback above 80 years. Under LEED-EB, the Ozone protection prerequisite recognizes that if replacing chillers is not economically feasible, or if the simple-payback of the replacement is greater than 10 years, an alternate compliance path would be acceptable. The path recommended is that the CFC-based refrigerants be maintained, and the annual leakage be reduced to 5 percent for the life of the units (the requirements for LEED-EB). We believe that this indicates that flexibility can be granted when economic conditions are adverse, and would like to propose that such flexibility to granted to the LEED CS EAc1 in this particular case. Chiller replacement in this building is not economically feasible, but the owner has committed nonetheless to phase in new chillers over the period of 5 years. The 5-year period is primarily due to the large economic burden required by a replacement that does not have a reasonable payback. Computer modeling projects that with this replacement the Core & Shell will meet the 2 credit requirement for EAc1. We propose that replacing the chillers over 5 years is much better than retaining the current chillers, both for energy use and for ozone-depletion reasons - even with care for CFC leakage. With the owners committed to phasing in the new non-CFC chillers within 5 years, will this be acceptable to use the new, planned chillers for meeting the 2 point requirement for EAc1?