Our project consists of multifamily rental units. We are performing the energy model using TRACE 700, a program that meets ASHRAE Standard 140-2004: Building Thermal Envelope and Fabric Load Tests. TRACE 700 does not have the capability of modeling domestic hot water energy usage. In order to account for domestic hot water energy usage we are proposing to use the Department of Energy sponsored Lawrence Berkeley National Laboratory calculation methodology. The spreadsheet can be found at www.doa.state.wi.us/docs_view2.asp?docid=2249. This spreadsheet estimates the energy consumption of water heaters based on power source, energy factor, and recovery efficiency. In addition, the spreadsheet estimates the energy reductions associated with hot water consumption of Energy Star clothes washers and dishwashers. According to the CIR ruling dated 4/25/2007, credit cannot be taken for low flow fixtures accounted for in WE credit 3. However, clothes washers and dishwashers are not accounted for in LEED NC v2.2 WE credit 3. An exceptional calculation in accordance with Appendix G will be provided to demonstrate energy savings for the Energy Star appliance itself. In addition, we believe the reduction in the amount of hot water required by Energy Star clothes washers and dishwashers should be accounted for in the water heating calculation. The basis for these calculations found at http://hes.lbl.gov/hes/aboutwhm.html will be uploaded as supporting documentation. 1. Can we use the Lawrence Berkeley National Laboratory spreadsheet since TRACE 700 does not model energy consumption for domestic water heaters? 2. Can the energy savings for the reduced hot water consumption for Energy Star clothes washers and dishwashers be accounted for in the domestic hot water energy consumption calculation?
The applicant is asking for confirmation that LBNL spreadsheet calculations can be used to document domestic hot water use and asking if hot water savings resulting from Energy Star clothes washers and dishwashers can be accounted for in the exceptional calculation. 1. It seems that the LBNL spreadsheet calculations are an appropriate method for calculating domestic hot water use and for documenting the energy savings associated with Energy Star equipment. However in order to be accepted as an exceptional calculation, be sure to include a detailed narrative with all assumptions and supporting calculations with the submittal. 2. Yes, energy savings for reduced hot water consumption can be counted in DHW energy calculation. ***Please note, this CIR was updated on 7/10/2009.***