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Monitored Energy Performance of Electrochromic Windows Controlledfor Daylight and Visual Comfort

Description: A 20-month field study was conducted to measure the energy performance of south-facing large-area tungsten-oxide absorptive electrochromic (EC) windows with a broad switching range in a private office setting. The EC windows were controlled by a variety of means to bring in daylight while minimizing window glare. For some cases, a Venetian blind was coupled with the EC window to block direct sun. Some tests also involved dividing the EC window wall into zones where the upper EC zone was controlled to admit daylight while the lower zone was controlled to prevent glare yet permit view. If visual comfort requirements are addressed by EC control and Venetian blinds, a 2-zone EC window configuration provided average daily lighting energy savings of 10 {+-} 15% compared to the reference case with fully lowered Venetian blinds. Cooling load reductions were 0 {+-} 3%. If the reference case assumes no daylighting controls, lighting energy savings would be 44 {+-} 11%. Peak demand reductions due to window cooling load, given a critical demand-response mode, were 19-26% maximum on clear sunny days. Peak demand reductions in lighting energy use were 0% or 72-100% compared to a reference case with and without daylighting controls, respectively. Lighting energy use was found to be very sensitive to how glare and sun is controlled. Additional research should be conducted to fine-tune EC control for visual comfort based on solar conditions so as to increase lighting energy savings.
Date: September 23, 2005
Creator: Lee, Eleanor S.; DiBartolomeo, Dennis L.; Klems, Joseph; Yazdanian, Mehry & Selkowitz, Stephen E.
Partner: UNT Libraries Government Documents Department

Energy Implications of Economizer Use in California Data Centers

Description: In the US, data center operations currently account for about 61 billion kWh/y of electricity consumption, which is more than 1.5percent of total demand. Data center energy consumption is rising rapidly, having doubled in the last five years. A substantial portion of data-center energy use is dedicated to removing the heat generated by the computer equipment. Data-center cooling load might be met with substantially reduced energy consumption with the use of air-side economizers. This energy saving measure, however, has been shown to expose servers to an order-of-magnitude increase in indoor particle concentrations with an unquantified increase in the risk of equipment failure. An alternative energy saving option is the use of water-side economizers, which do not affect the indoor particle concentration but require additional mechanical equipment and tend to be less beneficial in high humidity areas. Published research has only presented qualitative benefits of economizer use, providing industry with inadequate information on which to base their design decisions. Energy savings depend on local climate and the specific building-design characteristics. In this paper, based on building energy models, we report energy savings for air-side and water-side economizer use in data centers in several climate zones in California. Results show that in terms of energy savings, air-side economizers consistently outperform water-side economizers, though the performance difference varies by location. Model results also show that conventional humidity restrictions must by relaxed or removed to gain the energy benefits of air-side economizers.
Date: August 1, 2008
Creator: Shehabi, Arman; Ganguly, Srirupa; Traber, Kim; Price, Hillary; Horvath, Arpad; Nazaroff, William W. et al.
Partner: UNT Libraries Government Documents Department

CONSERVATION OPTIONS IN RESIDENTIAL ENERGY USE: STUDIES USING THE COMPUTER PROGRAM TWOZONE

Description: A computer model called TWOZONE, which differentiates between the thermal behavior of the north and south zones of a house, is used to study the heating and cooling loads of single-family residences. The model agrees well with the available field data and with the NBSLD (NBSFAST) computer program. In this paper we resolve the furnace output into component loads. We show that depending on the climate, there is an optimum glass area and location in the house from the viewpoint of minimizing the yearly heating bill. The effectiveness of several window management strategies is studied. The energy savings and cost effectiveness of various retrofit measures such as ceiling and wall insulation, storm windows, and clock thermostat are evaluated for two different climates.
Date: August 1, 1977
Creator: Wall, L.W.; Dey, T.; Gadgil, A.J.; Lilly, A.B. & Rosenfeld, A.H.
Partner: UNT Libraries Government Documents Department

Demand Response and Open Automated Demand Response Opportunities for Data Centers

Description: This study examines data center characteristics, loads, control systems, and technologies to identify demand response (DR) and automated DR (Open Auto-DR) opportunities and challenges. The study was performed in collaboration with technology experts, industrial partners, and data center facility managers and existing research on commercial and industrial DR was collected and analyzed. The results suggest that data centers, with significant and rapidly growing energy use, have significant DR potential. Because data centers are highly automated, they are excellent candidates for Open Auto-DR. 'Non-mission-critical' data centers are the most likely candidates for early adoption of DR. Data center site infrastructure DR strategies have been well studied for other commercial buildings; however, DR strategies for information technology (IT) infrastructure have not been studied extensively. The largest opportunity for DR or load reduction in data centers is in the use of virtualization to reduce IT equipment energy use, which correspondingly reduces facility cooling loads. DR strategies could also be deployed for data center lighting, and heating, ventilation, and air conditioning. Additional studies and demonstrations are needed to quantify benefits to data centers of participating in DR and to address concerns about DR's possible impact on data center performance or quality of service and equipment life span.
Date: December 30, 2009
Creator: Ghatikar, Girish; Piette, Mary Ann; Fujita, Sydny; McKane, Aimee; Dudley, Junqiao Han; Radspieler, Anthony et al.
Partner: UNT Libraries Government Documents Department

Demand Shifting With Thermal Mass in Large Commercial Buildings:Field Tests, Simulation and Audits

Description: The principle of pre-cooling and demand limiting is to pre-cool buildings at night or in the morning during off-peak hours, storing cooling in the building thermal mass and thereby reducing cooling loads and reducing or shedding related electrical demand during the peak periods. Cost savings are achieved by reducing on-peak energy and demand charges. The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies (Braun 1990, Ruud et al. 1990, Conniff 1991, Andresen and Brandemuehl 1992, Mahajan et al. 1993, Morris et al. 1994, Keeney and Braun 1997, Becker and Paciuk 2002, Xu et al. 2003). This technology appears to have significant potential for demand reduction if applied within an overall demand response program. The primary goal associated with this research is to develop information and tools necessary to assess the viability of and, where appropriate, implement demand response programs involving building thermal mass in buildings throughout California. The project involves evaluating the technology readiness, overall demand reduction potential, and customer acceptance for different classes of buildings. This information can be used along with estimates of the impact of the strategies on energy use to design appropriate incentives for customers.
Date: September 1, 2005
Creator: Xu, Peng; Haves, Philip; Piette, Mary Ann & Zagreus, Leah
Partner: UNT Libraries Government Documents Department

Georgia Institute of Technology chilled water system evaluation and master plan

Description: As the host of the Olympic Village for the 1996 Atlanta Olympics, Georgia Tech has experienced a surge in construction activities over the last three years. Over 1.3 million square feet of new buildings have been constructed on the Georgia Tech campus. This growth has placed a strain on the Georgia Tech community and challenged the facilities support staff charged with planning and organizing utility services. In concert with Olympic construction, utility planners have worked to ensure long term benefits for Georgia Tech facilities while meeting the short term requirements of the Olympic Games. The concentration of building construction in the northwest quadrant of the campus allowed planners to construct a satellite chilled water plant to serve the needs of this area and provide the opportunity to integrate this section of the campus with the main campus chilled water system. This assessment and master plan, funded in part by the US Department of Energy, has evaluated the chilled water infrastructure at Georgia Tech, identified ongoing problems and made recommendations for long term chilled water infrastructure development and efficiency improvements. The Georgia Tech office of Facilities and RDA Engineering, Inc. have worked together to assemble relevant information and prepare the recommendations contained in this document.
Date: May 15, 1996
Partner: UNT Libraries Government Documents Department

Paving materials for heat island mitigation

Description: This report summarizes paving materials suitable for urban streets, driveways, parking lots and walkways. The authors evaluate materials for their abilities to reflect sunlight, which will reduce their temperatures. This in turn reduces the excess air temperature of cities (the heat island effect). The report presents the compositions of the materials, their suitability for particular applications, and their approximate costs (in 1996). Both new and resurfacing are described. They conclude that, although light-colored materials may be more expensive than conventional black materials, a thin layer of light-colored pavement may produce energy savings and smog reductions whose long-term worth is greater than the extra cost.
Date: November 1997
Creator: Pomerantz, M.; Akbari, H.; Chen, A.; Taha, H. & Rosenfeld, A. H.
Partner: UNT Libraries Government Documents Department

Position Paper, W236A/MWTF - tank heat loading

Description: Position Paper to develop and document a position on the selection of the heat removal capability that the MWTF Tank Ventilation Systems will be designed to remove. The purpose of this paper is to provide Project W-236A, Multi-function Waste Tank Facility, (MWTF) Project File documentation on the selection of the heat removal capability that MWTF Tank Ventilation Systems will be designed to remove. This information is necessary for designing a heat removal system to prevent the thermal limits of the tank structure from being exceeded. It is important to note that this paper is not for defining the tank mixer pump requirements, but is to be only used for defining and defending the normal heat generation rate that the ventilation system and other heat removal systems will be designed to remove. There are three main heat loads in the tanks of which two can be controlled to a certain extent through operational considerations. These two are mixing pump heat and heat of chemical addition. The third heat source is radionuclide content which can only be controlled by what wastes are pumped to the tank and whether it is diluted prior to pumping. Other heat loads such as transfer pumps were considered to be negligible. In addition, chemical addition is considered a transient situation that is rarely performed and will be treated as such.
Date: February 1, 1995
Creator: Groth, B.D.
Partner: UNT Libraries Government Documents Department

Validation on the thermal effect of roof with the spraying and green plants in an insulated building

Description: In recent years, roof-spraying and rooftop lawns has proved effective on roofs with poor thermal insulation. However, roofs of most buildings have insulating material to provide thermal insulation during the winter. The effects of such a practice have not previously been quantified. In this study, the authors conducted measurements of an insulated building to quantify the thermal effects of roof-spraying and rooftop lawns. Roof-spraying did not significantly reduce cooling loads, and required significant amounts of water. The conclusion is that roof spraying is not suitable for buildings with well-insulated roofs. Rooftop lawns, however, significantly stabilized the indoor temperature while additionally helping to mitigate the heat island phenomenon.
Date: March 20, 2004
Creator: Zhou, Nan; Gao, Weijun; Nishida, Masaru & Ojima, Toshio
Partner: UNT Libraries Government Documents Department

DEVELOPMENT OF A HYDRONIC ROOFTOP UNIT -- HYPAK

Description: The majority of US commercial floor space is cooled by rooftop HVAC units (RTU's). RTU popularity derives chiefly from their low initial cost and relative ease of service access without disturbing building occupants. Unfortunately, current RTU's are inherently inefficient due to a combination of characteristics that unnecessarily increase cooling loads and energy use. Existing RTU's in the U.S. consume an estimated 2.4 quads annually. Inefficient RTU's create an estimated 3.5% of U.S. CO{sub 2} emissions, thus contributing significantly to global warming. Also, RTU's often fail to maintain adequate ventilation air and air filtration. This project was developed to evaluate the feasibility of a radically new ''HyPak'' RTU design that significantly and cost-effectively increases RTU performance and delivered air quality. The objective of the HyPak Project was to design, develop and test a hydronic RTU that provides a quantum improvement over conventional RTU performance. Our proposal targeted 60% and 50% reduction in electrical energy use by the HyPak RTU for dry and humid climates, respectively, when compared with a conventional unit.
Date: March 25, 2004
Creator: Lee, Eric; Bourne, Dick & Berman, Mark
Partner: UNT Libraries Government Documents Department

Climate Change Impacts on Residential and Commercial Loads in the Western U.S. Grid

Description: This report presents a multi-disciplinary modeling approach to quickly quantify climate change impacts on energy consumption, peak load, and load composition of residential and commercial buildings. This research focuses on addressing the impact of temperature changes on the building cooling load in 10 major cities across the Western United States and Canada. Our results have shown that by the mid-century, building yearly energy consumption and peak load will increase in the Southwest. Moreover, the peak load months will spread out to not only the summer months but also spring and autumn months. The Pacific Northwest will experience more hot days in the summer months. The penetration of the air conditioning (a/c) system in this area is likely to increase significantly over the years. As a result, some locations in the Pacific Northwest may be shifted from winter peaking to summer peaking. Overall, the Western U.S. grid may see more simultaneous peaks across the North and South in summer months. Increased cooling load will result in a significant increase in the motor load, which consumes more reactive power and requires stronger voltage support from the grid. This study suggests an increasing need for the industry to implement new technology to increase the efficiency of temperature-sensitive loads and apply proper protection and control to prevent possible adverse impacts of a/c motor loads.
Date: September 30, 2008
Creator: Lu, Ning; Taylor, Zachary T.; Jiang, Wei; Xie, YuLong; Leung, Lai R.; Correia, James et al.
Partner: UNT Libraries Government Documents Department

Energy performance analysis of prototype electrochromic windows

Description: This paper presents the results of a study investigating the energy performance of three newly developed prototype electrochromic devices. The DOE-2.1 E energy simulation program was used to analyze the annual cooling, lighting, and total electric energy use and peak demand as a function of window type and size. The authors simulated a prototypical commercial office building module located in the cooling-dominated locations of Phoenix, AZ and Miami, FL. Heating energy use was also studied in the heating-dominated location of Madison, WI. Daylight illuminance was used to control electrochromic state-switching. Two types of window systems were analyzed; i.e., the outer pane electrochromic glazing was combined with either a conventional low-E or a spectrally selective inner pane. The properties of the electrochromic glazings are based on measured data of new prototypes developed as part of a cooperative DOE-industry program. The results show the largest difference in annual electric energy performance between the different window types occurs in Phoenix and is about 6.5 kWh/m{sup 2} floor area (0.60 kWh/ft{sup 2}) which can represent a cost of about $.52/m{sup 2} ($.05/ft{sup 2}) using electricity costing $.08/kWh. In heating-dominated locations, the electrochromic should be maintained in its bleached state during the heating season to take advantage of beneficial solar heat gain which would reduce the amount of required heating. This also means that the electrochromic window with the largest solar heat gain coefficient is best.
Date: December 1, 1996
Creator: Sullivan, R.; Rubin, M. & Selkowitz, S.
Partner: UNT Libraries Government Documents Department

Desiccant dehumidification and cooling systems assessment and analysis

Description: The objective of this report is to provide a preliminary analysis of the principles, sensitivities, and potential for national energy savings of desiccant cooling and dehumidification systems. The report is divided into four sections. Section I deals with the maximum theoretical performance of ideal desiccant cooling systems. Section II looks at the performance effects of non-ideal behavior of system components. Section III examines the effects of outdoor air properties on desiccant cooling system performance. Section IV analyzes the applicability of desiccant cooling systems to reduce primary energy requirements for providing space conditioning in buildings. A basic desiccation process performs no useful work (cooling). That is, a desiccant material drying air is close to an isenthalpic process. Latent energy is merely converted to sensible energy. Only when heat exchange is applied to the desiccated air is any cooling accomplished. This characteristic is generic to all desiccant cycles and critical to understanding their operation. The analyses of Section I show that desiccant cooling cycles can theoretically achieve extremely high thermal CoP`s (>2). The general conclusion from Section II is that ventilation air processing is the most viable application for the solid desiccant equipment analyzed. The results from the seasonal simulations performed in Section III indicate that, generally, the seasonal performance of the desiccant system does not change significantly from that predicted for outdoor conditions. Results from Section IV show that all of the candidate desiccant systems can save energy relative to standard vapor-compression systems. The largest energy savings are achieved by the enthalpy exchange devise.
Date: September 1, 1997
Creator: Collier, R.K. Jr.
Partner: UNT Libraries Government Documents Department

New tools for the evaluation of daylighting strategies and technologies

Description: The use of daylight for the illumination of building interiors has the potential to enhance the quality of the environment while providing opportunities to save energy by replacing or supplementing electric lighting. Moreover, it has the potential to reduce heating and cooling loads, which offer additional energy saving opportunities as well as reductions in HVAC equipment sizing and cost. All of these benefits, however, assume proper use of daylighting strategies and technologies, whose performance depends on the context of their application. On the other hand, improper use can have significant negative effects on both comfort and energy requirements, such as increased glare and cooling loads. To ensure proper use, designers need design tools that model the dynamic nature of daylight and accurately predict performance with respect to a multitude of performance criteria, extending beyond comfort and energy to include aesthetics, cost, security, safety, etc.
Date: March 1, 1998
Creator: Papamichael, K.; Hitchcock, R.; Ehrlich, C. & Carroll, B.
Partner: UNT Libraries Government Documents Department

Measured energy savings of light colored roofs: Results from three California demonstration sites

Description: Measured data and computer simulations have demonstrated the impact of roof albedo in reducing cooling energy use in buildings. Savings are a function of both climate and the amount of roof insulation. The cooling energy savings for reflective roofs are highest in hot climates. A reflective roof may also lead to higher heating energy use. Reflective coatings are also used in commercial buildings to protect the roofing membrane, and hence, maintain and prolong the useful life of the roof. Reflectivity of coatings changes with weathering and aging which in turn could have an effect on building cooling-energy savings. For that reason, reflective roof coatings are not primarily marketed for their energy savings potential. To monitor the field performance of reflective coatings, the authors initiated a demonstration project where three commercial buildings in California were painted with light-colored roof coatings. The buildings are two medical care centers and one drug store. At all sites, the roof reflectance, both fresh and aged, and cooling energy use were monitored. In addition, they measured temperature throughout the roof systems and inside the conditioned space. In the monitored buildings, increasing the roof reflectance from an initial value of about 20% to 60%, dropped the roof temperature on hot summer afternoons by about 45 F. Summertime standard-weekday average daily air-conditioning savings were 18% (198 kWh) in the first medical office building, 13% (86 kWh) in the second medical office building, and 2% (13 kWh) in the drug store. The overall u-value of the roofs had dictated the impact of roof reflectance.
Date: June 1, 1998
Creator: Akbari, H.; Gartland, L. & Konopacki, S.
Partner: UNT Libraries Government Documents Department

Load calculation and system evaluation for electric vehicle climate control

Description: Providing air conditioning for electric vehicles (EVs) represents an important challenge, because vapor compression air conditioners, which are common in gasoline powered vehicles, may consume a substantial part of the total energy stored in the EV battery. This report consists of two major parts. The first part is a cooling and heating load calculation for electric vehicles. The second part is an evaluation of several systems that can be used to provide the desired cooling and heating in EVs. Four cases are studied. Short range and full range EVs are each analyzed twice, first with the regular vehicle equipment, and then with a fan and heat reflecting windows, to reduce hot soak. Recent legislation has allowed the use of combustion heating whenever the ambient temperature drops below 5{degrees}C. This has simplified the problem of heating, and made cooling the most important problem. Therefore, systems described in this project are designed for cooling, and their applicability to heating at temperatures above 5{degrees}C is described. If the air conditioner systems cannot be used to cover the whole heating load at 5{degrees}C, then the vehicle requires a complementary heating system (most likely a heat recovery system or electric resistance heating). Air conditioners are ranked according to their overall weight. The overall weight is calculated by adding the system weight and the weight of the battery necessary to provide energy for system operation.
Date: October 27, 1993
Creator: Aceves-Saborio, S. & Comfort, W. J. III
Partner: UNT Libraries Government Documents Department

Cleanroom Energy Efficiency: Metrics and Benchmarks

Description: Cleanrooms are among the most energy-intensive types of facilities. This is primarily due to the cleanliness requirements that result in high airflow rates and system static pressures, as well as process requirements that result in high cooling loads. Various studies have shown that there is a wide range of cleanroom energy efficiencies and that facility managers may not be aware of how energy efficient their cleanroom facility can be relative to other cleanroom facilities with the same cleanliness requirements. Metrics and benchmarks are an effective way to compare one facility to another and to track the performance of a given facility over time. This article presents the key metrics and benchmarks that facility managers can use to assess, track, and manage their cleanroom energy efficiency or to set energy efficiency targets for new construction. These include system-level metrics such as air change rates, air handling W/cfm, and filter pressure drops. Operational data are presented from over 20 different cleanrooms that were benchmarked with these metrics and that are part of the cleanroom benchmark dataset maintained by Lawrence Berkeley National Laboratory (LBNL). Overall production efficiency metrics for cleanrooms in 28 semiconductor manufacturing facilities in the United States and recorded in the Fabs21 database are also presented.
Date: July 7, 2010
Creator: Initiative, International SEMATECH Manufacturing; Mathew, Paul A.; Tschudi, William; Sartor, Dale & Beasley, James
Partner: UNT Libraries Government Documents Department

A bottom-up engineering estimate of the aggregate heating andcooling loads of the entire U.S. building stock

Description: A recently completed project for the U.S. Department of Energy's (DOE) Office of Building Equipment combined DOE-2 results for a large set of prototypical commercial and residential buildings with data from the Energy Information Administration (EIA) residential and commercial energy consumption surveys (RECS, CBECS) to estimate the total heating and cooling loads in U.S. buildings attributable to different shell components such as windows, roofs, walls, etc., internal processes, and space-conditioning systems. This information is useful for estimating the national conservation potentials for DOE's research and market transformation activities in building energy efficiency. The prototypical building descriptions and DOE-2 input files were developed from 1986 to 1992 to provide benchmark hourly building loads for the Gas Research Institute (GRI) and include 112 single-family, 66 multi-family, and 481 commercial building prototypes. The DOE study consisted of two distinct tasks : (1) perform DOE-2 simulations for the prototypical buildings and develop methods to extract the heating and cooling loads attributable to the different building components; and (2) estimate the number of buildings or floor area represented by each prototypical building based on EIA survey information. These building stock data were then multiplied by the simulated component loads to derive aggregated totals by region, vintage, and building type. The heating and cooling energy consumption of the national building stock estimated by this bottom-up engineering approach was found to agree reasonably well with estimates from other sources, although significant differences were found for certain end-uses. The main added value from this study, however, is the insight it provides about the contributing factors behind this energy consumption, and what energy savings can be expected from efficiency improvements for different building components by region, vintage, and building type.
Date: August 1, 2000
Creator: Huang, Yu Joe & Brodrick, Jim
Partner: UNT Libraries Government Documents Department

Data Center Energy Benchmarking: Part 3 - Case Study on an ITEquipment-testing Center (No. 20)

Description: The data center in this study had a total floor area of 3,024 square feet (ft{sup 2}) with one-foot raised-floors. It was a rack lab with 147 racks, and was located in a 96,000 ft{sup 2} multi-story office building in San Jose, California. Since the data center was used only for testing equipment, it was not configured as a critical facility in terms of electrical and cooling supply. It did not have a dedicated chiller system but was served by the main building chiller plant and make-up air system. Additionally it was served by only a single electrical supply with no provision for backup power in the event of a power outage. The Data Center operated on a 24 hour per day, year-round cycle, and users had full-hour access to the data center facility. The study found that data center computer load accounted for 15% of the overall building electrical load, while the total power consumption attributable to the data center including allocated cooling load and lighting was 22% of the total facility load. The density of installed computer loads (rack load) in the data center was 61 W/ft{sup 2}. Power consumption density for all data center allocated load (including cooling and lighting) was 88 W/ft{sup 2}, approximately eight times the average overall power density in rest of the building (non-data center portion). The building and its data center cooling system was provided with various energy optimizing systems that included the following: (1) Varying chilled water flow rate through variable speed drives on the primary pumps. (2) No energy losses due to nonexistence of UPS or standby generators. (3) Minimized under-floor obstruction that affects the delivery efficiency of supply air. (4) Elimination of dehumidification/humidification within the CRAH units. For the data center, 70% of the overall electric power was the ...
Date: July 1, 2007
Creator: Xu, Tengfang & Greenberg, Steve
Partner: UNT Libraries Government Documents Department

Data Center Energy Benchmarking: Part 4 - Case Study on aComputer-testing Center (No. 21)

Description: The data center in this study had a total floor area of 8,580 square feet (ft{sup 2}) with one-foot raised-floors. It was a rack lab with 440 racks, and was located in a 208,240 ft{sup 2} multi-story office building in San Jose, California. Since the data center was used only for testing equipment, it was not configured as a critical facility in terms of electrical and cooling supply. It did not have a dedicated chiller system but served by the main building chiller plant and make-up air system. Additionally, it was served by a single electrical supply with no provision for backup power. The data center operated on a 24 hour per day, year-round cycle, and users had all hour full access to the data center facility. The study found that data center computer load accounted for 23% of the overall building electrical load, while the total power consumption attributable to the data center including allocated cooling load and lighting was 30% of the total facility load. The density of installed computer loads (rack load) in the data center was 63 W/ft{sup 2}. Power consumption density for all data center allocated load (including cooling and lighting) was 84 W/ft{sup 2}, approximately 12 times the average overall power density in rest of the building (non-data center portion). For the data center, 75% of the overall electric power was the rack critical loads, 11% of the power was consumed by chillers, 9% by CRAH units, 1% by lighting system, and about 4% of the power was consumed by pumps. The ratio of HVAC to IT power demand in the data center in this study was approximately 0.32. General recommendations for improving overall data center energy efficiency include improving the lighting control, airflow optimization, and control of mechanical systems serving the data center ...
Date: August 1, 2007
Creator: Xu, Tengfang & Greenberg, Steve
Partner: UNT Libraries Government Documents Department

Hybrid Ground-Source Heat Pump Installations: Experiences, Improvements, and Tools

Description: One innovation to ground-source heat pump (GSHP, or GHP) systems is the hybrid GSHP (HyGSHP) system, which can dramatically decrease the first cost of GSHP systems by using conventional technology (such as a cooling tower or a boiler) to meet a portion of the peak heating or cooling load. This work uses three case studies (two cooling-dominated, one heating-dominated) to demonstrate the performance of the hybrid approach. Three buildings were studied for a year; the measured data was used to validate models of each system. The models were used to analyze further improvements to the hybrid approach, and establish that this approach has positive impacts, both economically and environmentally. Lessons learned by those who design and operate the systems are also documented, including discussions of equipment sizing, pump operation, and cooling tower control. Finally, the measured data sets and models that were created during this work are described; these materials have been made freely available for further study of hybrid systems.
Date: June 30, 2011
Creator: Hackel, Scott & Pertzborn, Amanda
Partner: UNT Libraries Government Documents Department

Comparative Study of Four Passive Building Energy Simulations DOE 2.1, BLAST, SUNCAT 2.4, DEROB-III

Description: Four building energy analysis codes are compared using two direct gain building models with Madison TMY weather data. Hourly temperature profiles and annual heating and cooling loads are compared and discussed. An analytic verification technique is described and used to investigate performance of the four codes. An anomaly is discovered in one of the codes, and the analytic verification technique is used to test a modified version of this code.
Date: October 1, 1980
Creator: Judkoff, R.; Wortman, D.; Christensen, C.; O'Doherty, R.; Simms, D. & Hannifan, M.
Partner: UNT Libraries Government Documents Department

Strategy Guideline: Accurate Heating and Cooling Load Calculations

Description: This guide presents the key criteria required to create accurate heating and cooling load calculations and offers examples of the implications when inaccurate adjustments are applied to the HVAC design process. The guide shows, through realistic examples, how various defaults and arbitrary safety factors can lead to significant increases in the load estimate. Emphasis is placed on the risks incurred from inaccurate adjustments or ignoring critical inputs of the load calculation.
Date: June 1, 2011
Creator: Burdick, A.
Partner: UNT Libraries Government Documents Department

Manufactured Home Energy Audit (MHEA)Users Manual (Version 7)

Description: The Manufactured Home Energy Audit (MHEA) is a software tool that predicts manufactured home energy consumption and recommends weatherization retrofit measures. It was developed to assist local weatherization agencies working with the U.S. Department of Energy (DOE) Weatherization Assistance Program. Whether new or experienced, employed within or outside the Weatherization Assistance Program, all users can benefit from incorporating MHEA into their manufactured home weatherization programs. DOE anticipates that the state weatherization assistance programs that incorporate MHEA into their programs will find significant growth in the energy and cost savings achieved from manufactured home weatherization. The easy-to-use MHEA uses a relatively standard Windows graphical interface for entering simple inputs and provides understandable, usable results. The user enters information about the manufactured home construction, heating equipment, cooling equipment appliances, and weather site. MHEA then calculates annual energy consumption using a simplified building energy analysis technique. Weatherization retrofit measures are evaluated based on the predicted energy savings after installation of the measure, the measure cost, and the measure life. Finally, MHEA recommends retrofit measures that are energy and cost effective for the particular home being evaluated. MHEA evaluates each manufactured home individually and takes into account local weather conditions, retrofit measure costs, and fuel costs. The recommended package of weatherization retrofit measures is tailored to the home being evaluated. More traditional techniques apply the same package of retrofit measures to all manufactured homes, often the same set of measures that are installed into site-built homes. Effective manufactured home weatherization can be achieved only by installing measures developed specifically for manufactured homes. The unique manufactured home construction characteristics require that each of these measures is evaluated separately in order to devise a package of measures that will result in high energy and dollar savings. MHEA stands apart from other building energy analysis tools in ...
Date: January 27, 2003
Creator: Gettings, M.B.
Partner: UNT Libraries Government Documents Department