The BLOOMhouse:Zero Net Energy Housing

The 2007 University of Texas Solar Decathlon House is called the BLOOMhouse because it represents the “seed” of new ideas for zero net energy housing. The University of Texas student team developed a prefabricated 7.9 kW stand-alone solar-powered modular house that sits lightly on the land and forms the superstructure for photovoltaic technologies and a sustainable approach to the building envelope. The prefabricated house can be adapted to a specific site and modified for the needs of a different site within a different climatic zone, and client context. Recognizing that consumers look to Solar Decathlon entries for ideas of how to integrate renewable energy technologies into their own homes this house will serve as a working example to homeowners, homebuilders, and architects. The Solar Decathlon is an international initiative and University competition sponsored by the U.S. Department of Energy, designed to stimulate research, industry and education to advance renewable energy technologies, with a specific focus on building-integrated photovoltaics. Now entering its fourth cycle, the Decathlon provides a unique opportunity to envision, fabricate and test the possibilities of highly efficient modern dwellings. Our team of architecture and engineering faculty and students under the direction of Professor Michael Garrison, Professor Samantha Randall, Professor Atila Novoselac, and Lecturer Russell Krepart constructed a completely stand-alone solar-powered home that serves as a catalyst for change, leading the residential housing industry toward more sustainable practices while addressing the need for well designed, appropriately diverse, economically viable, and environmentally responsible housing. Through use of solar power and energy efficient design, this project offers homeowners the means to directly participate in the energy economy, moving from energy consumers to energy producers. The Solar Decathlon completion occurs every two years and is run by the National Renewable Energy Laboratory, which requires a portable structure of a fairly modest scale, with a dual prescription for both exhibition and inhabitation. The Program calls for the design to appeal to the normal modern American lifestyle of the general public -- the solar decathlon house is designed to support all the power needs of a typical household, including lighting, cooking, heating and cooling, and telecommunications. There should also be enough energy remaining to charge an electric vehicle for getting around. The competition requires the construction of the home "offsite". It should have a maximum dwelling footprint of 800 square feet, suitable for two people and mobile, so that it can be transported for a temporary exhibition "village," on the National Mall. The home has to be installed in four days, occupied and tested during the competition and then subsequently removed and shipped back to Austin. The University of Texas has participated in the competitions in 2002, 2005 and 2007

The BLOOMhouse:Zero Net Energy Housing

The 2007 University of Texas Solar Decathlon House is called the BLOOMhouse because it represents the “seed” of new ideas for zero net energy housing. The University of Texas student team developed a prefabricated 7.9 kW stand-alone solar-powered modular house that sits lightly on the land and forms the superstructure for photovoltaic technologies and a sustainable approach to the building envelope. The prefabricated house can be adapted to a specific site and modified for the needs of a different site within a different climatic zone, and client context. Recognizing that consumers look to Solar Decathlon entries for ideas of how to integrate renewable energy technologies into their own homes this house will serve as a working example to homeowners, homebuilders, and architects. The Solar Decathlon is an international initiative and University competition sponsored by the U.S. Department of Energy, designed to stimulate research, industry and education to advance renewable energy technologies, with a specific focus on building-integrated photovoltaics. Now entering its fourth cycle, the Decathlon provides a unique opportunity to envision, fabricate and test the possibilities of highly efficient modern dwellings. Our team of architecture and engineering faculty and students under the direction of Professor Michael Garrison, Professor Samantha Randall, Professor Atila Novoselac, and Lecturer Russell Krepart constructed a completely stand-alone solar-powered home that serves as a catalyst for change, leading the residential housing industry toward more sustainable practices while addressing the need for well designed, appropriately diverse, economically viable, and environmentally responsible housing. Through use of solar power and energy efficient design, this project offers homeowners the means to directly participate in the energy economy, moving from energy consumers to energy producers. The Solar Decathlon completion occurs every two years and is run by the National Renewable Energy Laboratory, which requires a portable structure of a fairly modest scale, with a dual prescription for both exhibition and inhabitation. The Program calls for the design to appeal to the normal modern American lifestyle of the general public -- the solar decathlon house is designed to support all the power needs of a typical household, including lighting, cooking, heating and cooling, and telecommunications. There should also be enough energy remaining to charge an electric vehicle for getting around. The competition requires the construction of the home "offsite". It should have a maximum dwelling footprint of 800 square feet, suitable for two people and mobile, so that it can be transported for a temporary exhibition "village," on the National Mall. The home has to be installed in four days, occupied and tested during the competition and then subsequently removed and shipped back to Austin. The University of Texas has participated in the competitions in 2002, 2005 and 2007

Internal convective heat transfer modeling: Critical review and discussion of experimentally derived correlations

Heat is transferred through building envelopes by conduction, radiation, and convection. Of these, convective heat transfer is often the weakest 'link' in the overall heat transfer model. While conduction and radiation heat transfer are supported by well-established analytical and numerical models, the treatment of convection is much less rigorous. Convection modeling involves solution of fluid dynamics problems in which the complexity of an enclosed space's geometry and the diversity of indoor airflow patterns require many fit-for-purpose convection correlations. These must take into account specifics of the space and of the heating ventilation and air-conditioning (HVAC) system. This paper provides an overview of the current knowledge on the modeling of convective heat transfer in load calculation and building energy simulation programs. The paper also discusses various issues related to the robustness of convection coefficient correlations, and reports on new experiments conducted to test the sensitivity of existing convection correlations. The discussed issues relate to: (1) the non-uniformity of the indoor temperature field; (2) the selection of a proper characteristic dimension; (3) the effect of adiabatic and non-adiabatic obstructions in the zone; and (4) the impact of airflow disturbance

Passive Reduction of Human Exposure to Indoor Ozone

Reactive building materials offer an opportunity to provide indoor air cleaning with minimal energy use. Laboratory and test house experiments provide evidence that indoor ozone concentrations can be diminished by activated carbon (AC) and unpainted gypsum wallboard (GWB) panels. These two materials are highly reactive with ozone and produce few byproducts. when measured in a 14.2 m3 stainless-steel chamber, the mean deposition velocities to the materials were 5.3 m h-1 for AC and 2.4 m h-1 for GWB for a variety of airflow and relative humidity conditions. The ozone decay rates for both the materials were also measured in an unoccupied 34.5 m3 bedroom under various mixing conditions. In this case, ozone removal increased relative to background by 27-100% with a 4.4 m2 panel of a reactive material placed on one wall of the bedroom. The ozone decay rate for the bedroom increased over background by approximately 2-3 h-1 for GWB and 2-7 h-1 for AC. Application of a mass balance model for a typical home demonstrates that effectiveness for ozone removal depends weakly on the air exchange rate and strongly on the panel material, panel area, and mixing conditions. An ozone removal effectiveness of over 80% is possible with sufficient panel area and positioning that provides elevated air speeds near the panels