Lab Test Report Combi System Assessment

GTI used a creative way to assess the energy benefits of combi service for single family homes.  The Virtual Test Home (VTH) consists of multiple test rigs and associated algorithms that simulate real world conditions in a controlled, repeatable laboratory environment.  The VTH can be used for gas and electric space and water heating equipment. Unlike the Annual Fuel Utilization Efficiency (AFUE) and Heating Seasonal Performance Factor (HSPF) that are typical single-rating point methods for space heating equipment, the VTH provides performance characterizations across a wide range of part-loads ranging from 1-100% and at various temperatures. The performance characterizations are then incorporated in building energy modeling software, such as EnergyPlus™, to estimate annual appliance efficiencies, and quantify potential annual energy, emissions, and cost savings for various equipment in various buildings and climates. The comparison of the present model predictions and literature values indicate that the models provide a reasonable estimate of energy consumption in all California climate zones.