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Final Report: Healthy and Energy-Efficient Housing in Hot and Humid Climates: A Model Design

EPA Grant Number: SU831854
Title: Healthy and Energy-Efficient Housing in Hot and Humid Climates: A Model Design
Investigators: Yang, Xudong , DeMarco, Gerald , James, Jacqueline , Laas, Michael , Tang, Shijie , Wang, Yunqiu , Xu, Yue , Yan, Wei
Institution: University of Miami
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: September 1, 2004 through May 30, 2005
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity, and the Planet (2004)
Research Category: Pollution Prevention/Sustainable Development

Description:

Objective:

On a whole, buildings are responsible for using over 17% of the world’s fresh water, 25% of its wood produce, and 40% of its material and energy flows. The residential sector of construction uses 27% of the total energy consumption in the world, according to the World Resource Institute. Just about half of Florida’s energy use is by buildings. Residential homes consume approximately 55% of that total energy. About 90% of home’s energy is for electrical use, and one third of this is solely for room air conditioning. Sick building syndrome (SBS) due to poor air quality and mold is a serious problem in homes especially in hot and humid climates. For these reasons design and construction of buildings is focusing more on “green” and sustainable building practices.

Today’s architects and engineers face many decisions when designing buildings. Houses in hot and humid climates experience unique and severe climate conditions that can cause mold, excessive energy consumption, and poor indoor air quality. Low energy and environmental impact housing can be achieved by applying innovative and sustainable technologies. Most buildings in hot and humid climates can reduce their energy use by at least 15-30%. Building energy consumption can be reduced as much as 60-75% if the most efficient technologies are employed. Building green is also an opportunity to use our resources efficiently while creating healthier buildings that improve human health, build a better environment, and provide energy and cost savings.

Phase I of this project was dedicated to the development and research of innovative technologies to be integrated into the building of homes in hot and humid climates. These advancements were specifically tailored to ensure occupant’s health, sustainability and reduction of the impact of building materials and building itself on local and global environments. It was aimed at creating a cost effective and comfortable dwelling while conserving resources such as water and energy. A number of sustainable design concepts and technologies were implemented in the model house design. The study was centered on the following sustainability concepts:

Summary/Accomplishments (Outputs/Outcomes):

A contemporary design was completed by the design team for the physical model of the house in this study. It boasts features that recognize design principles such as orientation, internal room zoning, shading for windows and walls, insulation, ventilation, thermal mass, energy saving appliances, natural lighting and landscape design. With the help of existing energy and indoor air quality evaluation tools, these features of the house along with the concepts mentioned above were quantitatively evaluated and compared to the design without the added innovations.

After obtaining weather data for the location of the proposed house, a simple energy performance program confirms that with the implementation of the innovations, the temperature inside the house fell within the comfort zone at anytime throughout the year. The temperature remains between 76.8°F to 77.9°F on average. The house is designed so as to allow stack ventilation through ventilation near the top of the house, opening on the fist floor and large windows on both levels of the house when outdoor air is suitable for natural ventilation. The walls were insulated with R20 insulation and the roof with R30. The use of ceiling fans was also expected to contribute to energy saving. Comparing energy-efficient schedule with the regular scheme by the simple energy simulation software, we found that the cooling load, total energy and cost of total energy for the former scheme are 38%, 17% and 22% less than the latter one respectively. More rigorous energy simulations taking into account all aspects of the energy savings measures (passive and active) are yet to be performed.

A computation fluid dynamics (CFD) program was utilized to simulate the airflow surrounding the house. It was found at that the addition of trees along the west (in the path of the prevailing wind) wall does not significantly affect the flow of wind. The shapes and size of trees were chosen based upon the worst case scenario. The resulting velocity was 2m/s to 4mJs with or without the trees. In terms of shading, the trees provided added shading.

A study comparing the VOC concentrations using green vs. non-green materials was performed. The non-green materials selected included pressure treated decking wood, ceramic floor tile, oilbased paint and a wood stain. The green materials that serve the same purpose as the non-green materials included trex decking material, vinyl floor tile and water-based paint. It was found that the total VOC concentration using non-green materials would be more than 80 times that using green materials. The cost of each material was also recorded and then further scaled up to that of the residential building discussed. The difference in the cost of the materials was only about three thousand dollars ($3000).

Research of the grey water usage in Miami shows that due to the shallow aquifer (only six feet), grey water usage is limited. In that particular hot and humid area, the use of storm water will be restricted to landscaping. All other hot and humid climate regions will confirm to stipulations handed down by their local authority.

Energy-efficient moisture control poses significant challenges to hot and humid climates. Our industrial partner, Munters is experimenting with humidity solutions equipment for residential use. The Munters Humidity Control Unit (HCU) provides operators the ability to independently control temperature and humidity. The HCU is designed to treat 100% make-up air and works in conjunction with existing air conditioning system, air handling unit or energy recovery ventilator (ERV).

The PCO air cleaner chosen for this particular house includes a high grade prefilter with active carbon that absorbs odors and toxic gases. The hospital grade HEPA filter removes 99.97% of airborne particles including mold, spores and tobacco smoke. Second layer of activated carbon virtually eliminates all odors in the room. UV-C lamp is effective at eliminating bacteria and viruses smaller than 0.3 microns. The photocatalytic oxidation chamber provides 10,000 times the ultra violet intensity of comparable sunlight, which will break the chemical chain of VOCs and turn them into carbon dioxide, water and harmless gases.

Conclusions:

Significant measurable results out of the fist phase of this project is an integrated housing design that incorporates the innovative concepts and technologies to provide healthy, energy-efficient, and sustainable residential environment in hot and humid climates. Comparing energy-efficient schedule with the regular scheme by a simple energy simulation software, we found that the cooling load, total energy and cost of total energy for the former scheme are 38%, 17% and 22% less than the latter one respectively. More rigorous energy simulations taking into account all aspects of the energy savings measures (passive and active) are yet to be performed. We expect the model house will meet or exceed the set goal to reduce the overall energy consumption by 50% over the conventional housing designs in hot and humid climates with less than 5% overall cost increase. Meanwhile, indoor environment design which utilizes green building materials and UV/PCO air cleaning technologies will reduce the indoor air pollutant level (including VOCs and biocontaminants) to at least an order of magnitude lower.

Taking people, prosperity and planet into consideration, the design of this model house creates a comfortable balance where all three components can exist and flourish. The house would be able to be reproducible in different sizes and designs. This will be based on certain criteria (energy, environmental, cost) that combine to produce pass or fail results for the specific input. The multidisciplinary design team includes students and faculty advisors from various disciplines of engineering, architecture and basic science. The proposed project can benefit teaching and learning through courses, training and research. In the end, students should be able to bring technical information into the building design process, thereby help to construct sustainable buildings that would benefit people, prosperity, and planet.

Proposed Phase II objectives and strategies:

The objective of Phase II project is to further develop and evaluate a number of key technologies in sustainable housing design, and to set the stage for an implementation program and eventual commercialization. In this phase, the preliminary design will be finalized and the incorporation of the technological advancements into the physical model will be done. More comprehensive energy and indoor environmental quality evaluation tools will be used to test the design.

The complete work plan for Phase II includes

Phase II builds upon the successful completion of Phase I, and moves a significant step further by involving further development of technologies and more rigorous evaluation methods and implementation strategy. A construction company has joined the partnership to assist and advise in the implementation phase of this project.

Supplemental Keywords:

indoor air, health effect, VOC, pathogens, clean technologies, engineering, modeling, Southwest, Florida (FL), EPA Region 4, Air pollution prevention, moisture control, hot and humid, scientific discipline, sustainable industry/business, ecology and ecosystems, energy, engineering, environmental engineering, sustainable environment, technology for sustainable environment, waste reduction, alternative building, alternative building technology, architectural design, architecture, climate control and illumination building, ecological design, environmental conscious construction, environmentally conscious design, green building, green building design, green building materials, housing design for hot and humid climates, indoor air quality, passive cooling, pollution prevention design, solar energy, sustainable development, , Air, Sustainable Industry/Business, Scientific Discipline, RFA, POLLUTION PREVENTION, Technology for Sustainable Environment, Sustainable Environment, indoor air, waste reduction, Energy, Environmental Engineering, Ecology and Ecosystems, Engineering, energy conservation, pollution prevention design, environmental conscious construction, indoor air quality, green design, green building design, sustainable development, climate control and illumination building, waste minimization, solar energy, architectual design, ecological design, architecture, alternative building technology, passive cooling, energy efficiency, environmentally conscious design, housing design for hot and humid climates, alternative building

Progress and Final Reports:
Original Abstract

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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