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Energy efficiency and the environment: Innovative ways to improve air quality in the Los Angeles Basin

Description: This paper focuses on novel, innovative approaches for reducing or delaying the production of photochemical smog in the Los Angeles Basin. These approaches include modifying the surface characteristics of the basin by increasing surface albedo and an extensive tree-planting program. The changes in surface conditions are designed to reduce the basin air temperatures, especially during the summer months, which will result in two possible effects. First, a decrease in temperature would lead to a reduction in energy use with an associated decline in emissions of nitrogen oxides (NO[sub x]) and a lowering of evaporative emission of reactive organic gases. Reductions in these smog precursors could improve the air quality of the basin without imposing additional emissions regulations. The second effect is associated with the possible causal relationship between air temperature and smog formation (i.e., lower temperatures and lower incidence of smog). Since this approach to mitigating air emissions is broad, the studies to date have concentrated on how changes in surface characteristics affect the meteorological conditions of the basin and on how these meteorological changes subsequently affect smog production. A geographic information system database of key surface characteristics (i.e., vegetative cover, albedo, moisture availability, and roughness) was compiled, and these characteristics were evaluated using prognostic meteorological models. The results of two- and three-dimensional meteorological simulations will be presented and discussed in this paper.
Date: February 1, 1993
Creator: Ritschard, R.
Partner: UNT Libraries Government Documents Department

Energy efficiency in California laboratory-type facilities

Description: The central aim of this project is to provide knowledge and tools for increasing the energy efficiency and performance of new and existing laboratory-type facilities in California. We approach the task along three avenues: (1) identification of current energy use and savings potential, (2) development of a {ital Design guide for energy- Efficient Research Laboratories}, and (3) development of a research agenda for focused technology development and improving out understanding of the market. Laboratory-type facilities use a considerable amount of energy resources. They are also important to the local and state economy, and energy costs are a factor in the overall competitiveness of industries utilizing laboratory-type facilities. Although the potential for energy savings is considerable, improving energy efficiency in laboratory-type facilities is no easy task, and there are many formidable barriers to improving energy efficiency in these specialized facilities. Insufficient motivation for individual stake holders to invest in improving energy efficiency using existing technologies as well as conducting related R&D is indicative of the ``public goods`` nature of the opportunity to achieve energy savings in this sector. Due to demanding environmental control requirements and specialized processes, laboratory-type facilities epitomize the important intersection between energy demands in the buildings sector and the industrial sector. Moreover, given the high importance and value of the activities conducted in laboratory-type facilities, they represent one of the most powerful contexts in which energy efficiency improvements stand to yield abundant non-energy benefits if properly applied.
Date: July 31, 1996
Creator: Mills, E.; Bell, G. & Sartor, D.
Partner: UNT Libraries Government Documents Department

Analysis of climatic conditions and preliminary assessment of alternative cooling strategies for houses in California transition climate zones

Description: This is a preliminary scoping study done as part of the {open_quotes}Alternatives to Compressive Cooling in California Transition Climates{close_quotes} project, which has the goal of demonstrating that houses in the transitional areas between the coast and the Central Valley of California do not require air-conditioning if they are properly designed and operated. The first part of this report analyzes the climate conditions within the transitional areas, with emphasis on design rather than seasonal conditions. Transitional climates are found to be milder but more variable than those further inland. The design temperatures under the most stringent design criteria, e.g. 0.1 % annual, are similar to those in the Valley, but significantly lower under more relaxed design criteria, e.g., 2% annual frequency. Transition climates also have large day-night temperature swings, indicating significant potential for night cooling, and wet-bulb depressions in excess of 25 F, indicating good potential for evaporative cooling. The second part of the report is a preliminary assessment using DOE-2 computer simulations of the effectiveness of alternative cooling and control strategies in improving indoor comfort conditions in two conventional Title-24 houses modeled in various transition climate locations. The cooling measures studied include increased insulation, light colors, low-emissivity glazing, window overhangs, and exposed floor slab. The control strategies studied include natural and mechanical ventilation, and direct and two-stage evaporative cooling. The results indicate the cooling strategies all have limited effectiveness, and need to be combined to produce significant improvements in indoor comfort. Natural and forced ventilation provide similar improvements in indoor conditions, but during peak cooling periods, these will still be above the comfort zone. Two-stage evaporative coolers can maintain indoor comfort at all hours, but not so direct evaporative coolers.
Date: July 1, 1995
Creator: Huang, Y.J. & Zhang, H.
Partner: UNT Libraries Government Documents Department

Comparison of DOE-2 with measurements in the Pala Test houses

Description: The predictions of the DOE-2 program for building energy analysis have been compared with measurements in the Pala test houses near San Diego. This work is part of the California Institute for Energy Efficiency {open_quotes}Alternatives to Compressor Cooling in California Transition Zones{close_quotes} project in which DOE-2 is being used for parametric analysis of cooling strategies that reduce peak electrical power in hot, dry climates. To establish the validity of DOE-2 for this kind of analysis the program was compared with room air temperature measurements in a {open_quotes}low-mass{close_quotes} house with conventional insulated study wall construction and a {open_quotes}high-mass{close_quotes} house with insulated concrete walls. To test different aspects of the DOE-2 calculation, four different unconditioned thermal configurations of these houses were considered: unshaded windows, shaded windows, white exterior surfaces, and forced night ventilation. In all cases DOE-2 agreed well with the air temperature measurements, with a mean deviation between simulation and measurement ranging from 0.2 to 1.0 K depending on configuration and type of house. Using a development version of DOE-2 comparisons with inside surface temperature measurements were also made. These comparisons also showed good agreement.
Date: July 1995
Creator: Meldem, R. & Winkelmann, F.
Partner: UNT Libraries Government Documents Department

Numerical simulation of cold flow patterns and turbulent mixing in a simplified burner

Description: The COYOTE computer program was used to simulate the flow field and turbulent mixing near the fuel and air inlets in a simplified burner. The authors report the results of four cold flow calculations that illustrate several interesting phenomena in addition to demonstrating the capabilities of the basic hydrodynamics model and the turbulence model. They also demonstrate some interesting facets of the hydrodynamics of burners. They summarize their findings as follows: (1) two different grids gave vastly different answers, underscoring the importance of assuring grid-independence in numerical solutions; (2) cold flow patterns are much different than reactive flow fields, making it unwise to apply conclusions from the former to the latter; (3) the problem is elliptic, and it is necessary to include the whole furnace in the calculations; (4) the flow patterns exhibited weakly unstable, almost metastable, modes that make it difficult to ascertain when steady conditions have been obtained. The long range goals of this study are to identify parameters that affect the production of NO{sub x} and to discover methods of reducing emissions while maintaining or improving burner efficiency.
Date: October 1, 1994
Creator: Cloutman, L.D.
Partner: UNT Libraries Government Documents Department

Analysis of energy use in building services of the industrial sector in California: Two case studies

Description: Energy-use patterns in many of California's fastest-growing industries are not typical of the existing mix of industries in the US. Many California firms operate small- and medium-sized facilities housed in buildings used simultaneously or interchangeably over time for commercial (office, retail, warehouse) and industrial activities. In these industrial subsectors, the energy required for building services (providing occupant comfort and necessities like lighting, HVAC, office equipment, computers, etc.) may be at least as important as the more familiar process energy requirements -- especially for electricity and on-peak demand. Electricity for building services is sometimes priced as if it were base loaded like process uses; in reality this load varies significantly according to occupancy schedules and cooling and heating loads, much as in any commercial building. Using informal field surveys, simulation studies, and detailed analyses of existing data (including utility commercial/industrial audit files), we studied the energy use of this industrial subsector through a multi-step procedure: (1) characterizing non-process building energy and power use in California industries, (2) identifying conservation and load-shaping opportunities in industrial building services, and (3) investigating industrial buildings and system design methodologies. In an earlier report, we addressed these issues by performing an extensive survey of the existing publicly available data, characterizing and comparing the building energy use in this sector. In this report, we address the above objectives by examining and analyzing energy use in two industrial case-study facilities in California. Based on the information for the case studies, we discuss the design consideration for these industrial buildings, characterize their energy use, and review their conservation and load-shaping potentials. In addition, we identify and discuss some research ideas for further investigation.
Date: September 1, 1991
Creator: Akbari, H. & Sezgen, O.
Partner: UNT Libraries Government Documents Department

High-albedo materials for reducing building cooling energy use

Description: One simple and effective way to mitigate urban heat islands, i.e., the higher temperatures in cities compared to those of the surrounds, and their negative impacts on cooling energy consumption is to use high-albedo materials on major urban surfaces such as rooftops, streets, sidewalks, school yards, and the exposed surfaces of parking lots. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building's envelope (direct effect) and also by lowering the urban air temperature in the neighborhood of the building (indirect effect). This project is an attempt to address high-albedo materials for buildings and to perform measurements of roof coatings. We search for existing methods and materials to implement fighter colors on major building and urban surfaces. Their cost effectiveness are examined and the possible related technical, maintenance, and environmental problems are identified. We develop a method for measuring albedo in the field by studying the instrumentation aspects of such measurements. The surface temperature impacts of various albedo/materials in the actual outdoor environment are studied by measuring the surface temperatures of a variety of materials tested on an actual roof. We also generate an albedo database for several urban surfaces to serve as a reference for future use. The results indicate that high-albedo materials can have a large impact on the surface temperature regime. On clear sunny days, when the solar noon surface temperatures of conventional roofing materials were about 40{degrees}C (72{degrees}F) warmer than air, the surface temperature of high-albedo coatings were only about 5{degrees}C warmer than air. In the morning and in the late afternoon, the high-albedo materials were as cool as the air itself. While conventional roofing materials warm up by an average 0.055{degrees}C/(W m{sup {minus}2}), the high-albedo surfaces warm up by an average 0.015{degrees}C/(W m{sup {minus}2}).
Date: January 1, 1992
Creator: Taha, H.; Sailor, D. & Akbari, H.
Partner: UNT Libraries Government Documents Department

Research and Development Conference CIEE Program 1992

Description: CIEE`s second annual Research and Development Conference will introduce you to some of the results achieved to date through CIEE-sponsored multiyear research performed in three programs: Building Energy Efficiency, Air Quality Impacts of Energy Efficiency, and End-Use Resource Planning. Results from scoping studies, Director`s discretionary research, and exploratory research will also be featured in this report.
Date: November 1, 1992
Partner: UNT Libraries Government Documents Department

Cost-effectiveness of controlling emissions for various alternative-fuel vehicle types, with vehicle and fuel price subsidies estimated on the basis of monetary values of emission reductions

Description: Emission-control cost-effectiveness is estimated for ten alternative-fuel vehicle (AFV) types (i.e., vehicles fueled with reformulated gasoline, M85 flexible-fuel vehicles [FFVs], M100 FFVs, dedicated M85 vehicles, dedicated M100 vehicles, E85 FFVS, dual-fuel liquefied petroleum gas vehicles, dual-fuel compressed natural gas vehicles [CNGVs], dedicated CNGVs, and electric vehicles [EVs]). Given the assumptions made, CNGVs are found to be most cost-effective in controlling emissions and E85 FFVs to be least cost-effective, with the other vehicle types falling between these two. AFV cost-effectiveness is further calculated for various cases representing changes in costs of vehicles and fuels, AFV emission reductions, and baseline gasoline vehicle emissions, among other factors. Changes in these parameters can change cost-effectiveness dramatically. However, the rank of the ten AFV types according to their cost-effectiveness remains essentially unchanged. Based on assumed dollars-per-ton emission values and estimated AFV emission reductions, the per-vehicle monetary value of emission reductions is calculated for each AFV type. Calculated emission reduction values ranged from as little as $500 to as much as $40,000 per vehicle, depending on AFV type, dollar-per-ton emission values, and baseline gasoline vehicle emissions. Among the ten vehicle types, vehicles fueled with reformulated gasoline have the lowest per-vehicle value, while EVs have the highest per-vehicle value, reflecting the magnitude of emission reductions by these vehicle types. To translate the calculated per-vehicle emission reduction values to individual AFV users, AFV fuel or vehicle price subsidies are designed to be equal to AFV emission reduction values. The subsidies designed in this way are substantial. In fact, providing the subsidies to AFVs would change most AFV types from net cost increases to net cost decreases, relative to conventional gasoline vehicles.
Date: December 31, 1993
Creator: Wang, M. Q.
Partner: UNT Libraries Government Documents Department

Improved modelling of HVAC system/envelope inteactions in residential buildings

Description: General building energy simulation programs do not typically simulate interactions between HVAC systems and building envelopes. For this reason, a simulation tool which includes interactions between duct systems, building envelopes, and heating and cooling appliances in residential buildings has been developed. The simulation tool uses DOE- 2 (to model space conditioning loads and zone temperatures), COMIS (an airflow network solver), and a model of duct leakage and conduction losses. Three augmentations to the simulation tool are presented herein, along with sample results. These include: (1) modeling of steady-state thermosiphon flows in ducts, (2) improved simplified modeling of duct thermal mass effects, and (3) modeling of multi-speed space conditioning equipment. Multi-speed air conditioners are shown to be more sensitive to duct efficiency than single-speed equipment, because their efficiency decreases with increasing cooling load. Thermosiphon flows through duct systems are estimated to be 5-16% of the total heating load, depending on the duct insulation level. The duct dynamics model indicates that duct thermal mass decreases the energy delivery efficiency of the distribution system by 1-6 percentage points.
Date: March 1, 1995
Creator: Modera, M.P. & Treidler, B.
Partner: UNT Libraries Government Documents Department

Energy efficiency improvements for refrigerator/freezers using prototype doors containing gas-filled panel insulating systems

Description: Energy efficiency improvements in domestic refrigerator/freezers, are directly influenced by the overall thermal performance of the cabinet and doors. An advanced system for reducing heat gain is Gas-Filled Panel thermal insulation technology. Gas-Filled Panels contain a low-conductivity, inert gas at atmospheric pressure and employ a reflective baffle to suppress radiation and convection within the gas. This paper presents energy use test results for a 1993 model 500 liter top mount refrigerator/freezer operated with its original doors and with a series of alternative prototype doors. Gas-Filled Panel technology was used in two types of prototype refrigerator/freezer doors. In one design, panels were used in composite with foam in standard metal door pans; this design yielded no measurable energy savings. In the other design, special polymer door pans were fitted with panels that fill nearly all of the available insulation volume; this design yielded a 6.5% increase in energy efficiency for the entire refrigerator/freezer. The EPA Refrigerator Analysis computer program has been used to predict the change in daily energy consumption with the alternative doors. The computer model also projects a 25% energy efficiency improvement for a refrigerator/freezer that would use Gas-Filled Panel insulation throughout the cabinet as well as the doors.
Date: January 1, 1995
Creator: Griffith, B.; Arasteh, D. & Tuerler, D.
Partner: UNT Libraries Government Documents Department

Development of a model to simulate the performance of hydronic radiant cooling ceilings

Description: A significant amount of the electrical energy used to cool non-residential buildings equipped with all-air systems is drawn by the fans that transport the cool air through the thermal distribution system. Hydronic radiant cooling systems have the potential to reduce the amount of air transported through the building by separating the tasks of ventilation and thermal conditioning. Because of the physical properties of water, hydronic radiant cooling systems can transport a given amount of thermal energy using less than 5170 of the otherwise necessary fan energy. This improvement alone significantly reduces the energy consumption and peak power requirement of the air conditioning system. Hydronic radiant cooling systems have been used for more than 30 years in hospital rooms to provide a draft-free, thermally stable environment. The energy savings and peak-load characteristics of these systems have not yet been analyzed systematically. Moreover, adequate guidelines for design and control of these systems do not exist. This has prevented their widespread application to other building types. The evaluation of the theoretical performance of hydronic systems could be made most conveniently by computer models. Energy analysis programs such as DOE-2 do not have the capability to simulate hydronic radiant systems yet. In this paper the development of a model that can simulate accurately the dynamic performance of hydronic radiant cooling systems is described. The model is able to calculate loads, heat extraction rates, room air temperature and room surface temperature distributions, and can be used to evaluate issues such as thermal comfort, controls, system sizing, system configuration and dynamic response. The model was created with the Simulation Problem Analysis and Research Kernel (SPARK) developed at the Lawrence Berkeley Laboratory, which provides a methodology for describing and solving the dynamic, non-linear equations that correspond to complex physical systems.
Date: June 1, 1995
Creator: Stetiu, C. & Feustel, H.E.
Partner: UNT Libraries Government Documents Department

Development of a simulation tool to evaluate the performance of radiant cooling ceilings

Description: Considerable electrical energy used to cool nonresidential buildings equipped with All-Air Systems is drawn by the fans that transport the cool air through the thermal distribution system. Hydropic Cooling Systems have the potential to reduce the amount of air transported through the building by separating the tasks of ventilation and thermal conditioning. Due to the physical properties of water, Hydropic Cooling Systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. They are suited to the dry climates that are typical of California and been used for more than 30 years in hospital rooms. However, energy savings and peak-load characteristics have not yet been analyzed. Adequate guidelines for their design and control systems has prevented lack of their widespread application to other building types. Evaluation of theoretical performance of Hydropic Systems could be made by computer models. Energy analysis programs such as DOE-2 do not yet have the capacity to simulate Hydropic Cooling Systems. Scope of this project is developing a model that can accurately simulate the dynamic performance of Hydropic Radiant Cooling Systems. The model can calculate loads, heat extraction rates, room air temperature and room surface temperature distributions, and can be used to evaluate issues such as thermal comfort, controls, system sizing, system configuration and dynamic response. The model was created with the LBL Simulation Problem Analysis and Research Kernel (SPARK), which provides a methodology for describing and solving the dynamic, non-linear equations that correspond to complex physical systems. Potential for Hydropic Radiant Cooling Systems applications can be determined by running this model for a variety of construction types in different California climates.
Date: June 1, 1995
Creator: Stetiu, C.; Feustel, H.E. & Winkelmann, F.C.
Partner: UNT Libraries Government Documents Department

The reduction of NO{sub x} by HNCO

Description: A chemical mechanism for the reduction of NO{sub x} by HNCO has been constructed to model NO{sub x} reduction in exhausts typical of natural gas combustion with the addition of radical boosters (fuel). Variables considered were the initial concentrations of NO, NO{sub 2}, CO, O{sub 2}, CH{sub 4}, H{sub 2}, and HNCO as well as initial temperatures. The chemical model was validated by comparing results with earlier model calculations of Miller and Bowman and with the experiments of Caton and Siebers and Lyon and Cole. Agreement with experiments was satisfactory. The reduction chemistry must be preceded by thermal ignition chemistry which generates radicals. The lowest temperature for which ignition occurs is the optimum temperature for reduction and defines the beginning of the temperature window. Reduction was not achieved for the ``natural gas exhaust`` for a reasonable residence time. Additional H{sub 2} added to the exhaust mixture enhanced reduction, but the addition of CO and CH{sub 4} did not. Under some conditions the computed sensitivity coefficient for nitrogen species and temperature exhibited self-similarity. Four reaction paths were identified which controlled the fate of the NO: the conversion of NO to NO{sub 2} via HO{sub 2}, the conversion of NO{sub 2} to NO via reaction with H or O, the reduction of NO via NCO, and the reduction of NO from reactions with NH{sub i} species. The relative importance of the four was determined by the initial conditions.
Date: October 1, 1992
Creator: Brown, N. J. & Garay, J.
Partner: UNT Libraries Government Documents Department

The design and evaluation of integrated envelope and lighting control strategies for commercial buildings

Description: This study investigates control strategies for coordinating the variable solar-optical properties of a dynamic building envelope system with a daylight controlled electric lighting system to reduce electricity consumption and increase comfort in the perimeter zone of commercial buildings. Control strategy design can be based on either simple, instantaneous measured data, or on complex, predictive algorithms that estimate the energy consumption for a selected operating state of the dynamic envelope and lighting system. The potential benefits of optimizing the operation of a dynamic envelope and lighting system are (1) significant reductions in electrical energy end-uses - lighting, and cooling due to solar and lighting heat gains - over that achieved by conventional static envelope and lighting systems, (2) significant reductions in peak demand, and (3) increased occupant visual and thermal comfort. The DOE-2 building energy simulation program was used to model two dynamic envelope and lighting systems, an automated venetian blind and an electrochromic glazing system, and their control strategies under a range of building conditions. The energy performance of simple control strategies are compared to the optimum performance of a theoretical envelope and lighting system to determine the maximum potential benefit of using more complex, predictive control algorithms. Results indicate that (1) predictive control algorithms may significantly increase the energy-efficiency of systems with non-optimal solar-optical properties such as the automated venetian blind, and (2) simpler, non-predictive control strategies may suffice for more advanced envelope systems 1 incorporating spectrally selective, narrow-band electrochromic coatings.
Date: June 1, 1994
Creator: Lee, E. S. & Selkowitz, S. E.
Partner: UNT Libraries Government Documents Department

Measured commercial load shapes and energy-use intensities and validation of the LBL end-use disaggregation algorithm

Description: The Southern California Edison Company (SCE) has conducted an extensive metering project in which electricity end use in 53 commercial buildings in Southern California has been measured. The building types monitored include offices, retail stores, groceries, restaurants, and warehouses. One year (June 1989 through May 1990) of the SCE measured hourly end-use data are reviewed in this report. Annual whole-building and end-use energy use intensities (EUIs) and monthly load shapes (LSs) have been calculated for the different building types based on the monitored data. This report compares the monitored buildings' EUIs and LSs to EUIs and LSs determined using whole-building load data and the End-Use Disaggregation Algorithm (EDA). Two sets of EDA determined EUIs and LSs are compared to the monitored data values. The data sets represent: (1) average buildings in the SCE service territory and (2) specific buildings that were monitored.
Date: January 1, 1993
Creator: Akbari, H.; Rainer, L.; Heinemeier, K.; Huang, J. & Franconi, E.
Partner: UNT Libraries Government Documents Department

A method of optimizing solar control and daylighting performance in commercial office buildings

Description: We present a method for analyzing the annual cooling and lighting electricity use and peak demand associated with varying fenestration and lighting strategies in commercial office buildings. A prototypical office building module consisting of four perimeter zones and a central core zone was defined and a series of DOE-2 building energy simulations were completed to create a data base for varying fenestration and lighting system parameters. Using regression analysis procedures, we characterize energy and peak performance patterns as a function of solar aperture, defined as the product of shading coefficient and window-to-wall ratio, and effective daylighting aperture, defined as the product of visible transmittance and window-to-wall ratio. Optimum performance consists of defining the solar and effective daylighting aperture values that minimize annual energy consumption and peak demand, a process easily facilitated by the methods described herein.
Date: September 1, 1992
Creator: Sullivan, R.; Lee, E. S. & Selkowitz, S.
Partner: UNT Libraries Government Documents Department

Residential air-distribution systems: Interactions with the building envelope

Description: Residential air distribution systems, used both for heating and cooling and less commonly for ventilation, have important interactions with the building envelope. These systems can either be enclosed within the envelope or pass outside the envelope (in which case they represent an extension of the envelope). This paper addresses the three major types of interaction between air distribution systems that pass outside the envelope and single-family buildings: (1) duct leakage and duct conduction when the distribution fan is off, which act like a thermal bridge in the envelope; (2) duct leakage during system operation, which creates large changes in the quantity and location of air infiltration and exfiltration through the envelope; and (3) supply/return flow imbalances within individual zones during fan operation, which create elevated envelope pressure differentials, infiltration rates, and exfiltration rates. A simulation tool that was developed to take into account all of these interactions is presented and applied. The simulation tool, based upon the DOE-2 thermal simulation model, a multi-zone airflow network model (COMIS), and an equipment model for the ducts, is used to examine the magnitude of all three interactions. The interaction issues examined include air infiltration/exfiltration magnitude and location, overall thermal exchange when the system is off, and air exchange when the system is operating, with and without internal doors closed. The most surprising result of the analyses presented was that the thermal siphon effect for perfectly sealed ducts was shown to have an impact on the heat exchange between the house and unconditioned spaces that can be more than four times larger than that due to typical duct leakage when the fan is not in operation. This result suggests that this issue merits more careful examination than it has received in the past.
Date: July 1, 1992
Creator: Modera, M. P. & Jansky, R.
Partner: UNT Libraries Government Documents Department

Zone conditioning in a California foothill house

Description: The principal focus of the reported research is the performance of the installed zoned air distribution system in a house located in the foothills northeast of Sacramento California. The 297 m{sup 2} two story house contained a central air conditioner and an air distribution system with four dampered supply duct legs. The air conditioning system included a two speed fan and two speed compressor, with the air handler placed inside a closet and almost all the ducts located inside the building envelope. The uninsulated sheet metal ducts ran inside a space between stories and in interior walls. The performance parameters examined included: (1) duct leakage, (2) duct conduction, (3) zoning performance and (4) equipment efficiency impacts. In conclusion, two major points were made concerning the test house. The first was that substantial energy benefits were obtained by placing the ducts inside the conditioned space. The second was that the energy benefits from zoning the house were not realized, primarily due to thermal stratification and the open floor plan in the house. Secondary impacts lowering zoning performance were the k& of return duct dampers and leakage and conduction losses in the air distribution system. Utility programs or building standards promoting zoning as a means of conserving energy or reducing peak power demand should be aware of the many potential pitfalls that can arise with zone conditioning, particularly with dampered air distribution systems.
Date: December 1, 1993
Creator: Jump, D. & Modera, M.
Partner: UNT Libraries Government Documents Department

A spreadsheet for analyzing the in situ performance of fluorescent luminaires

Description: A spreadsheet program for determining system efficacy, power input and light output of common 4 ft fluorescent lighting systems under realistic operating conditions is described. The program uses accepted IES engineering principles to precisely account for ballast factor, existing thermal conditions and maintenance practices. The spreadsheet, which includes a data base of lamp and ballast performance data, can be used to calculate the cost-effectiveness of many common lighting retrofits.
Date: August 1, 1991
Creator: Rubinstein, F. & Zhang, Chin
Partner: UNT Libraries Government Documents Department

Field measurement of the interactions between heat pumps and attic duct systems in residential buildings

Description: Research efforts to improve residential heat-pump performance have tended to focus on laboratory and theoretical studies of the machine itself, with some limited field research having been focused on in-situ performance and installation issues. One issue that has received surprisingly little attention is the interaction between the heat pump and the duct system to which it is connected. This paper presents the results of a field study that addresses this interaction. Field performance measurements before and after sealing and insulating the duct systems were made on three heat pumps. From the pre-retrofit data it was found that reductions in heat-pump capacity due to low outdoor temperatures and/or coil frosting are accompanied by lower duct-system energy delivery efficiencies. The conduction loss reductions, and thus the delivery temperature improvements, due to adding duct insulation were found to vary widely depending on the length of the particular duct section, the thermal mass of that duct section, and the cycling characteristics of the heat-pump. In addition, it was found that the use of strip-heat back-up decreased after the retrofits, and that heat-pump cycling increased dramatically after the retrofits, which respectively increase and decrease savings due to the retrofits. Finally, normalized energy use for the three systems which were operated consistently pre- and post-retrofit showed an average reduction of 19% after retrofit, which corresponds to a chance in overall distribution-system efficiency of 24%.
Date: November 1, 1994
Creator: Modera, M.P. & Jump, D.A.
Partner: UNT Libraries Government Documents Department

Developing a dynamic envelope/lighting control system with field measurements

Description: The feasibility of an intelligent venetian blind/lighting control system was tested in a 1:3 scale model outdoors under variable sun and sky conditions. The control algorithm, block direct sun and meet the design workplane illuminance level, was implemented using commercially available and custom designed blind and lighting systems hardware. While blocking direct sunlight, the blinds were properly controlled to maintain the design workplane illuminance within a tolerance of -10%, +25% when there was sufficient daylight. When daylight levels alone were inadequate, the electric lighting control system maintained the design workplane illuminance. The electric lighting could be turned off if a user-specified time period at minimum power was exceeded. Lighting energy savings of 51-71% (southwest) and 37-75% (south) was attained for the period from 8:00 to 17:00 on clear sunny days, compared to a fixed, partially closed blind with the same lighting system. Practical details for implementation and commissioning are discussed. The impact of control variations, such as profile angle, time step interval, and control area, on energy demand is investigated.
Date: May 1, 1996
Creator: DiBartolomeo, D.L.; Lee, E.S.; Rubinstein, F.M. & Selkowitz, S.E.
Partner: UNT Libraries Government Documents Department

A review of electrochromic window performance factors

Description: The performance factors which will influence the market acceptance of electrochromic windows are reviewed. A set of data representing the optical properties of existing and foreseeable electrochromic window devices was generated. The issue of reflective versus absorbing electrochromics was explored. This data was used in the DOE 2.1 building energy model to calculate the expected energy savings compared to conventional glazings. The effects of several different control strategies were tested. Significant energy and peak electric demand benefits were obtained for some electrochromic types. Use of predictive control algorithms to optimize cooling control may result in greater energy savings. Initial economic results considering annual savings, cooling equipment cost savings, and electrochromic window costs are presented. Calculations of thermal and visual comfort show additional benefits from electrochromics but more work is needed to quantify their importance. The design freedom and aesthetic possibilities of these dynamic glazings should provide additional market benefits, but their impact is difficult to assess at this time. Ultimately, a full assessment of the market viability of electrochromics must consider the impacts of all of these issues.
Date: April 1, 1994
Creator: Selkowitz, S.E.; Rubin, M.; Lee, E.S.; Sullivan, R.; Finlayson, E. & Hopkins, D.
Partner: UNT Libraries Government Documents Department

Energy impacts of attic duct retrofits in Sacramento houses

Description: Inefficiencies in air distribution systems have been identified as a major source of energy loss in US sunbelt homes. Research indicates that approximately 30--40% of the thermal energy delivered to the ducts passing through unconditioned spaces is lost through air leakage and conduction through the duct walls. Field experiments over the past several years have well documented the expected levels of air leakage and the extent to which that leakage can be reduced by retrofit. Energy savings have been documented to a more limited extent, based upon a few field studies and simulation model results. Simulations have also indicated energy loss through ducts during the off cycle caused by thermosiphon-induced flows, however this effect had not been confirmed experimentally. A field study has been initiated to separately measure the impacts of combined duct leak sealing and insulation retrofits, and to optimize a retrofit protocol for utility DSM programs. This paper describes preliminary results from 6 winter and 5 summer season houses. These retrofits cut overall duct leakage area approximately 64%, which translated to a reduction in envelope ELA of approximately 14%. Wrapping ducts and plenums with R-6 insulation translated to a reduction in average flow-weighted conduction losses of 33%. These experiments also confirmed the appropriateness of using duct ELA and operating pressures to estimate leakage flows for the population, but indicated significant variations between these estimates and measured flows on a house by house basis. In addition, these experiments provided a confirmation of the predicted thermosiphon flows, both under winter and summer conditions. Finally, average material costs were approximately 20% of the total retrofit costs, and estimates of labor required for retrofits based upon these experiments were: 0.04 person-hrs/cm{sup 2} of duct sealed and 0.21 person-hrs/m{sup 2} of duct insulated.
Date: August 1, 1994
Creator: Jump, D. & Modera, M.
Partner: UNT Libraries Government Documents Department