Why Conduct Experiments in Real Houses?
The primary objective of the field-based experiments in residential buildings research is to validate the cost-effective limits of efficiency savings that can be achieved by current technologies in both existing and new homes using well-characterized field datasets. Field experiments are focused around evaluations of deep energy retrofit demonstration houses and the development of pilot community performance evaluation tools to accelerate deployment of home energy upgrades and efficient new homes. Results from field-based evaluations of advanced energy systems and strategies (e.g. heat pump water heaters, home automation, peak load control, solar thermal, building-integrated photovoltaics (BIPV), night cooling, high-R envelope retrofits, heat and energy recovery ventilators) are used to update the national measures database and BEopt models to improve the accuracy of energy savings predictions. These identify the most cost-effective approaches to achieving 30%+ energy savings.
One key objective in building systems research is to develop analysis capabilities to accurately predict the performance (e.g., energy, comfort, moisture) and associated cost impact of a particular energy conservation measure (ECM) or combination of ECMs for different building types, site conditions, and occupant behaviors. If the physics of the ECM and its interaction with the building system are adequately understood, then a whole-building energy simulation program can be a powerful tool for conducting cost-performance analyses. A wide range of scenarios may be analyzed for much less cost than measuring real systems requires, and the results can be intercompared because weather and occupant-driven loads are controllable input parameters.
It is important to understand that any newly-developed models for ECMs that have not been validated against empirical data are of limited use, since the accuracy of their outputs cannot be known. In many cases, field experiments are key to gathering the empirical data; however, by measuring the energy use or performance of parts of a building is not of interest, because the results cannot be generalized to apply to other buildings, weather conditions, locations, or occupant behaviors. A primary goal for field-based building science experiments, then, should be to add to the 'toolbox' of measurement-verified component models that form a basis for accurate whole-building building energy simulation programs. The steps that should be followed in formulating field research plans that address this goal effectively are outlined in subsequent pages.