The purpose of the Energy Simulations and Projected Statewide Energy Savings project is to develop reasonable energy performance and cost models for high-performance relocatable classrooms (RCs) across California climates. This project is broken into an initial and a final phase. In the initial phase, which took place during the past year, the characteristics of high- performance RCs were defined, modeling assumptions were developed, and a DOE-2 input dataset was developed and executed. A final modeling phase will take place in Year 3 after the energy and indoor environmental quality (IEQ) field studies are completed. The data from the field studies will be used to adjust the model inputs and assumptions so that the DOE-2 simulations can be refined. The refined simulations will be used to determine improved statewide energy savings and predicted energy usage for both standard and improved RCs.

The High-Performance Commercial Building System (HPCBS) RC energy-efficiency implementations are based on earlier work by Davis Energy Group with Pacific Gas and Electric Co. (PG&E), which culminated in the PG&E Premium Efficient Relocatable Classroom (PERC) program (Davis Energy Group 2000). The HPBCS RC specification is similar to the PERC Package 2 with two differences: the HPCBS heating, ventilation, and air conditioning (HVAC) system provides heat using a gas-heated hydronic coil rather than electric radiant panels, and the HPCBS roof has a white ("Cool Roof," AB 970) coating. We did not implement Package B Option 1, experimental displacement ventilation (DV). The addition of the DV system would have prevented us from studying the effectiveness of the Indirect/Direct Evaporative Cooler (IDEC) technology. For this study, the IDEC was the primary technology under investigation.

The following input specifications for HPCBS RCs were used to conduct the DOE-2 simulations. These specifications are similar to the details of actual classrooms specified by LBNL and currently under construction by American Modular Systems (Manteca CA) for two school districts in Northern California. The RC is a standard 24' x 40' modular classroom consisting of two 12' x 40' rigid steel frame modules connected to one another along the long axis. Detailed physical specifications are contained in the deliverables report for Element 6, Year 1 Diagrams of the RCs as used for modeling are provided in the DOE-2 Input Specifications deliverable (Apte et al. 2001) submitted by LBNL to the California Energy Commission (CEC) on April 18, 2001. The base case HVAC system consists of a wall-mounted heat pump with flex duct connected to two supply registers in the ceiling and a through-the-wall return. The HPCBS cooling system consists of a wall-mounted IDEC with flex duct connected to three supply registers in the ceiling and two through-the-wall gravity relief dampers. Heating is provided by a hydronic heating coil in the supply plenum connected to a wall-mounted instantaneous gas water heater.

The hydronic gas-heat system design developed at LBNL with DEG incorporates a low-pressure drop fan coil mounted in the IDEC discharge air stream as it enters the RC plenum and duct system. Heat is be supplied by an 85-% efficient, outdoor-mounted, power-vented natural gas (LPG options are available) instantaneous water heater by a water circulation pump and associated hydronic plumbing.

The existing IDEC temperature controller appears to have all of the necessary hardware to control the circulation pump, fan coil and room temperature. Hydronic fluid freeze protection is designed into the water heater. Finally, the heating is accomplished solely by the flow of outside air (400 cfm) provided by the IDEC air handler. DEG developed a sizing spreadsheet for this hydronic heating system for California Climate zones, indicating that it can be used to provide the heating needs of RCs in climates with outdoor temperatures of 32°F or lower. Peak electricity use by the system during heating is approximately 40W, compared with about 3kW for the conventional heat pump and 4kW for radiant electric heating. This change will result in a more efficient and cost-effective HVAC design with major peak electrical load reduction benefits.