Energy savings estimates and cost benefit calculations for high performance relocatable classrooms

This report addresses the results of detailed monitoring completed under Program Element 6 of Lawrence Berkeley National Laboratory's High Performance Commercial Building Systems (HPCBS) PIER program. The purpose of the Energy Simulations and Projected State-Wide Energy Savings project is to develop reasonable energy performance and cost models for high performance relocatable classrooms (RCs) across California climates. A key objective of the energy monitoring was to validate DOE2 simulations for comparison to initial DOE2 performance projections. The validated DOE2 model was then used to develop statewide savings projections by modeling base case and high performance RC operation in the 16 California climate zones. The HPCBS energy efficient RC design is based upon earlier work by Davis Energy Group with Pacific Gas and Electric Company (PG&E), which culminated in the PG&E Premium Efficient Relocatable Classroom (PERC) program (DEG 1997). The envelope energy efficiency measures selected for the HPCBS project are similar to the PERC Package 1 except the HPCBS package substitutes a white ("Cool Roof") coating for the radiant barrier in the attic space. In addition to the standard wall-mount heat pump system (HPAC), the HPCBS RCs utilize an advanced hybrid system combining an Indirect/Direct Evaporative Cooler (IDEC), which provides two-stage evaporative cooling, and an instantaneous gas-fired heater and hydronic coil for heating. Simulations described in this report add upon those conducted in program year one, with the benefit of data collected during the energy and indoor air and environmental quality (IEQ) field monitoring. Data from the field studies have been used to improve model inputs. The revised DOE2 analyses presented here provide an improved assessment of statewide energy performance for both base case and high performance RCs. Since the initiation of this project a new revision of the California Title 24 Building Standards has begun (scheduled for release in 2005). As part of this process, RCs were examined and new code enforcement procedures were developed which will result in new RCs having envelope energy features very close to the HPCBS design. Table 1 summarizes key energy features of the HPCBS RC package. Additional background information on the construction details and assumed operating characteristics of RCs, as well as full-year DOE2 performance projections, can be found in the 2001 project report entitled Relocatable Classroom DOE2 Analysis Report, (Apte et al 2001, Shendell et al 2002)