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Integrated Water/wastewater and Energy Strategies for Green Buildings and Communities (Workshop)
Citation:
Shi, J., M. Alahmad, C. Berryman, Y. Cho, S. Lau, H. Li, A. Schwer, Z. Shen, J. Stansbury, AND T. Zhang. Integrated Water/wastewater and Energy Strategies for Green Buildings and Communities (Workshop). Presented at National Association of Home Builders (NAHB) International Builders Show, Orlando, FL, January 12 - 15, 2011.
Impact/Purpose:
To inform the public.
Description:
This session will be organized for the project team from the University of Nebraska-Lincoln to present their first-year research findings resulted from a five year research project funded by the US EPA. There are four presentations as follows: 1. Life Cycle Assessment of Water Reuse Technologies in Residential Buildings and Developments The presentation will start with an overview on process-based Life-Cycle Assessment (LCA) and Economic Input-Output Life Cycle Assessment (EIO-LCA). An EIO-LCA model will be discussed for a simple greywater reuse system for landscape irrigation with a reuse volume of 1000 sq. ft. “unit” landscaping in four distinct climates. Detailed results from each climate will be analyzed using the metrics including greenhouse gas emissions, energy use, water use, and cost. An EIO-LCA model for a complicated greywater reuse system with treatment and storage will follow with the same evaluating criteria. The presentation will also cover an EIO-LCA model of an innovative water reuse system, green roof with evaporative cooling, use of greywater with energy-saving systems such as heat pumps and waste heat recovery, a dual water system in a residential community, risk assessment of greywater reuse, surface landscape irrigation, sub-surface irrigation, fireflow, evaporative cooling, flushing toilets and other indoor uses. 2. An Innovative Wastewater Energy Recovery System and Its Energy Performance for Water Heating and Space Heating / Cooling An innovative wastewater energy recovery system was developed for domestic water heating,and space heating and cooling of buildings in order to improve the overall efficiency and total energy input of building energy usage. This system adopts a multiple-function heat-pump system associated with outdoor air extraction and rejection to reclaim the energy from wastewater. A model has been established for the annual profiles of temperature and flowrate of hot-water and wastewater. The optimal operation strategies were developed and energy consumption of this new system was analyzed in detail with consideration of all energy-consumption components. Primary energy has been compared with a conventional building energy system with gas furnace space heating, package air-conditioning and electrical water heater for hot water heating. From a case study of a typical residential house with 4 family members and 3 bedrooms in New York, NY, the simulation results shows that energy consumptions decrease 32.0 %, 6.9 % and 80.9 %, respectively, for space heating, cooling and hot water heating. The total energy saving is as high as 39.1 % and the peak electricity demand reduces 23.0 % compared with the conventional system. This demonstrates the high energy-saving potential of this novel system. Fifteen cities were selected for further study in different climate zones in U.S.A.. Among these 15 cities, the minimum total energy saving is over 20%, while the maximum is 52.2%. Hot water heating has the most energy saving with over 65% reduction. However, the energy saving of space cooling system is influenced by the temperatures of outdoor air and sewage. By optimally controlling the temperature of sewage tank, significant energy saving could be achieved, especially in moderate outdoor temperature. 3. Combination of shredded tire biofilters and membrane bioreactors for reclamation of graywater With the increasing urgent water crisis, water reuse has been receiving more attention. Among several processes that can be used for graywater treatment, membrane bioreactor (MBR) technology receives more attention because 1) it can produce treated water that satisfies the criteria of the USEPA for water reuse; 2) it fits any plant sizes ranging from a single house to a whole community; and 3) its nature of physical filtration adds to the stability of treatment systems. However, membrane fouling and energy cost for aeration still remain the hindrances of wide application of the technique. The goal of this study was to evaluate the feasibility of coupling a biofilter filled with shredded tires as the medium with a MBR for graywater treatment. Currently, millions of tires are abandoned or stockpiled, which represents a health hazard to the public. The application of shredded tires as a medium of biofilters will not only serve as another solution to the disposal of discarded tires, but also mitigate membrane fouling and reduce the volume of the aeration tank and the energy cost of the BMR. Four biofilters linked with 4 MBRs were used in this study. The biofilters with different depths of the shredded tire medium were inoculated with activated sludge for biofilm accumulation, and then fed intermittently with artificial graywater for evaluation of their performance. The effluent of the biofilters was fed into MBRs. The performance of the MBRs was evaluated against different operation conditions. Results indicate that the shredded tire biofilters remove most of the contaminants in graywater; the MBRs can be used as a final step for removal of microbial residuals and turbidity. The combined process elongates the membrane fouling cycle and decreases the energy cost of the MBR, and hence, may be a promising technology for decentralized wastewater treatment at both household and community levels. 4. Virtual ZNETH Home A collaborative research project was initiated by the University of Nebraska’s Peter Kiewit Institute, USGBC Flatwater Chapter, and the Green Omaha Coalition to build a test home under the direction of Dr. Avery Schwer in the Durham School of Architectural Engineering and Construction. The test home integrates energy innovations with on-site renewable power solutions to achieve a zero net energy home. The project is named ZNETH, an acronym for Zero Net Energy Test Home. The ZNETH research project investigates effective approaches to achieving whole-house environmental and energy goals. It also investigates design and construction strategies leading to zero net energy homes as the basis for analyzing future residential and commercial performance. For building environment and energy innovations to be viable candidates over conventional approaches, it must be demonstrated that they can cost-effectively increase overall value and air quality while reducing energy use. This research analyzes system performance and costs as they relate to whole building performance, including interactions between advanced envelope methods, mechanical/electrical systems, lighting systems, space conditioning systems, hot water systems, appliances, plug loads, energy control systems, renewable energy systems, and on-site power generation systems. The virtual ZNETH home will enable the audience to walkthrough the ZNETH home in a virtual 3D environment, to review and evaluate green technologies implemented in the test home.
URLs/Downloads:
FOR FURTHER INFORMATION CONTACT JILL NEAL.PDF (PDF, NA pp, 21 KB, about PDF)Website
