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Review of Residential Low-Load HVAC Systems

Description: In support of the U.S. Department of Energy’s (DOE’s) Building America Program, Pacific Northwest National Laboratory (PNNL) conducted an investigation to inventory commercially available HVAC technologies that are being installed in low-load homes. The first step in this investigation was to conduct a review of published literature to identify low-load HVAC technologies available in the United States and abroad, and document the findings of existing case studies that have evaluated the performance of the identified technologies. This report presents the findings of the literature review, identifies gaps in the literature or technical understanding that must be addressed before low-load HVAC technologies can be fully evaluated, and introduces PNNL’s planned research and analysis for this project to address identified gaps and potential future work on residential low-load HVAC systems.
Date: September 1, 2013
Creator: Brown, Scott A.; Thornton, Brian & Widder, Sarah H.
Partner: UNT Libraries Government Documents Department

Performance Analysis of Two Alternative Hvac Systems for the Unt Zero Energy Lab

Description: This paper covers the simulation and comparison among three different HVAC (heating, ventilation & air conditioning)systems to achieve the goal of finding the most effective HVAC among these three in terms of human comfort, efficiency and cost considering North Texas climate. In the Zero Energy Lab at the University of North Texas, Denton, TX, the HVAC system of the building assembles with geothermal heat source. Here, water to water heat pump with radiant floor and water to air heat pump with air ducts provide heating & cooling of the building. In this paper electricity consumption, comfort, cost & efficiency analysis is done for the existing system using Energy Plus simulation software. Calibration of the simulated data of the existing system is done comparing with the actual data. Actual data is measured using 150 sensors that installed in Zero Energy Lab. After the baseline model calibration, simulation for ground source water to water heat pump, evaporative cooler with baseboard electric heater and water cooled electric chiller with baseboard electric heater (as a conventional system) is shown. Simulation results evaluate the life cycle cost (LCC) for these HVAC systems. The results of the comparison analysis among all the three HVAC systems show the most effective HVAC system among these three systems in North Texas weather. The results will make UNT Zero Energy lab a standard model towards a sustainable green future.
Date: August 2013
Creator: Hasib, Naimee
Partner: UNT Libraries

Simplifying the assessment of building vulnerability to chemical,biological and radiological releases

Description: The intentional or accidental release of airborne chemical, biological, or radiological materials can pose a significant threat to the health of building occupants. Pre-planning and emergency response measures, such as HVAC system manipulation and sheltering during an event, can significantly reduce the exposure of building occupants. A straightforward and comprehensive vulnerability assessment methodology is an essential tool for assisting building managers and operators in preparing for airborne hazards.
Date: January 1, 2005
Creator: Thatcher, T.L.; Wood, E.E.; Edelson, E.C. & Sextro, R.G.
Partner: UNT Libraries Government Documents Department

Wireless Demand Response Controls for HVAC Systems

Description: The objectives of this scoping study were to develop and test control software and wireless hardware that could enable closed-loop, zone-temperature-based demand response in buildings that have either pneumatic controls or legacy digital controls that cannot be used as part of a demand response automation system. We designed a SOAP client that is compatible with the Demand Response Automation Server (DRAS) being used by the IOUs in California for their CPP program, design the DR control software, investigated the use of cellular routers for connecting to the DRAS, and tested the wireless DR system with an emulator running a calibrated model of a working building. The results show that the wireless DR system can shed approximately 1.5 Watts per design CFM on the design day in a hot, inland climate in California while keeping temperatures within the limits of ASHRAE Standard 55: Thermal Environmental Conditions for Human Occupancy.
Date: June 30, 2009
Creator: Federspiel, Clifford
Partner: UNT Libraries Government Documents Department

Fuzzy Linguistic Knowledge Based Behavior Extraction for Building Energy Management Systems

Description: Significant portion of world energy production is consumed by building Heating, Ventilation and Air Conditioning (HVAC) units. Thus along with occupant comfort, energy efficiency is also an important factor in HVAC control. Modern buildings use advanced Multiple Input Multiple Output (MIMO) control schemes to realize these goals. However, since the performance of HVAC units is dependent on many criteria including uncertainties in weather, number of occupants, and thermal state, the performance of current state of the art systems are sub-optimal. Furthermore, because of the large number of sensors in buildings, and the high frequency of data collection, large amount of information is available. Therefore, important behavior of buildings that compromise energy efficiency or occupant comfort is difficult to identify. This paper presents an easy to use and understandable framework for identifying such behavior. The presented framework uses human understandable knowledge-base to extract important behavior of buildings and present it to users via a graphical user interface. The presented framework was tested on a building in the Pacific Northwest and was shown to be able to identify important behavior that relates to energy efficiency and occupant comfort.
Date: August 1, 2013
Creator: Wijayasekara, Dumidu & Manic, Milos
Partner: UNT Libraries Government Documents Department

Review of Pre- and Post-1980 Buildings in CBECS - HVAC Equipment

Description: PNNL was tasked by DOE to look at HVAC systems and equipment for Benchmark buildings based on 2003 CBECS data. This white paper summarizes the results of PNNL’s analysis of 2003 CBECS data and provides PNNL’s recommendations for HVAC systems and equipment for use in the Benchmark buildings.
Date: December 1, 2006
Creator: Winiarski, David W.; Jiang, Wei & Halverson, Mark A.
Partner: UNT Libraries Government Documents Department

Comparisons of HVAC Simulations between EnergyPlus and DOE-2.2 for Data Centers

Description: This paper compares HVAC simulations between EnergyPlus and DOE-2.2 for data centers. The HVAC systems studied in the paper are packaged direct expansion air-cooled single zone systems with and without air economizer. Four climate zones are chosen for the study - San Francisco, Miami, Chicago, and Phoenix. EnergyPlus version 2.1 and DOE-2.2 version 45 are used in the annual energy simulations. The annual cooling electric consumption calculated by EnergyPlus and DOE-2.2 are reasonablely matched within a range of -0.4percent to 8.6percent. The paper also discusses sources of differences beween EnergyPlus and DOE-2.2 runs including cooling coil algorithm, performance curves, and important energy model inputs.
Date: August 13, 2008
Creator: Hong, Tianzhen; Sartor, Dale; Mathew, Paul & Yazdanian, Mehry
Partner: UNT Libraries Government Documents Department

Measured Peak Equipment Loads in Laboratories

Description: This technical bulletin documents measured peak equipment load data from 39 laboratory spaces in nine buildings across five institutions. The purpose of these measurements was to obtain data on the actual peak loads in laboratories, which can be used to rightsize the design of HVAC systems in new laboratories. While any given laboratory may have unique loads and other design considerations, these results may be used as a 'sanity check' for design assumptions.
Date: September 12, 2007
Creator: Mathew, Paul A.
Partner: UNT Libraries Government Documents Department

Using measured equipment load profiles to 'right-size' HVACsystems and reduce energy use in laboratory buildings (Pt. 2)

Description: There is a general paucity of measured equipment load datafor laboratories and other complex buildings and designers often useestimates based on nameplate rated data or design assumptions from priorprojects. Consequently, peak equipment loads are frequentlyoverestimated, and load variation across laboratory spaces within abuilding is typically underestimated. This results in two design flaws.Firstly, the overestimation of peak equipment loads results in over-sizedHVAC systems, increasing initial construction costs as well as energy usedue to inefficiencies at low part-load operation. Secondly, HVAC systemsthat are designed without accurately accounting for equipment loadvariation across zones can significantly increase simultaneous heatingand cooling, particularly for systems that use zone reheat fortemperature control. Thus, when designing a laboratory HVAC system, theuse of measured equipment load data from a comparable laboratory willsupport right-sizing HVAC systems and optimizing their configuration tominimize simultaneous heating and cooling, saving initial constructioncosts as well as life-cycle energy costs.In this paper, we present datafrom recent studies to support the above thesis. We first presentmeasured equipment load data from two sources: time-series measurementsin several laboratory modules in a university research laboratorybuilding; and peak load data for several facilities recorded in anational energy benchmarking database. We then contrast this measureddata with estimated values that are typically used for sizing the HVACsystems in these facilities, highlighting the over-sizing problem. Next,we examine the load variation in the time series measurements and analyzethe impact of this variation on energy use, via parametric energysimulations. We then briefly discuss HVAC design solutions that minimizesimultaneous heating and cooling energy use.
Date: June 29, 2005
Creator: Mathew, Paul; Greenberg, Steve; Frenze, David; Morehead, Michael; Sartor, Dale & Starr, William
Partner: UNT Libraries Government Documents Department

WESBES: A Wireless Embedded Sensor for Improving Human Comfort Metrics using Temporospatially Correlated Data

Description: When utilized properly, energy management systems (EMS) can offer significant energy savings by optimizing the efficiency of heating, ventilation, and air-conditioning (HVAC) systems. However, difficulty often arises due to the constraints imposed by the need to maintain an acceptable level of comfort for a building’s occupants. This challenge is compounded by the fact that human comfort is difficult to define in a measurable way. One way to address this problem is to provide a building manager with direct feedback from the building’s users. Still, this data is relative in nature, making it difficult to determine the actions that need to be taken, and while some useful comfort correlations have been devised, such as ASHRAE’s Predicted Mean Vote index, they are rules of thumb that do not connect individual feedback with direct, diverse feedback sensing. As they are a correlation, quantifying effects of climate, age of buildings and associated defects such as draftiness, are outside the realm of this correlation. Therefore, the contribution of this paper is the Wireless Embedded Smart Block for Environment Sensing (WESBES); an affordable wireless sensor platform that allows subjective human comfort data to be directly paired with temporospatially correlated objective sensor measurements for use in EMS. The described device offers a flexible research platform for analyzing the relationship between objective and subjective occupant feedback in order to formulate more meaningful measures of human comfort. It could also offer an affordable and expandable option for real world deployment in existing EMS.
Date: August 1, 2012
Creator: Hewlett, Joel; Manic, Milos & Rieger, Craig
Partner: UNT Libraries Government Documents Department

Anti-Idling Battery for Truck Applications

Description: In accordance to the Assistance Agreement DE-EE0001036, the objective of this project was to develop an advanced high voltage lithium-ion battery for use in an all-electric HVAC system for Class-7-8 heavy duty trucks. This system will help heavy duty truck drivers meet the tough new anti-idling laws being implemented by over 23 states. Quallion will be partnering with a major OEM supplier of HVAC systems to develop this system. The major OEM supplier will provide Quallion the necessary interface requirements and HVAC hardware to ensure successful testing of the all-electric system. At the end of the program, Quallion will deliver test data on three (3) batteries as well as test data for the prototype HVAC system. The objectives of the program are: (1) Battery Development - Objective 1 - Define battery and electronics specifications in preparation for building the prototype module. (Completed - summary included in report) and Objective 2 - Establish a functional prototype battery and characterize three batteries in-house. (Completed - photos and data included in report); (2) HVAC Development - Objective 1 - Collaborate with manufacturers to define HVAC components, layout, and electronics in preparation for establishing the prototype system. (Completed - photos and data included in report) and Objective 2 - Acquire components for three functional prototypes for use by Quallion. (Completed - photos and data included in report).
Date: September 30, 2011
Creator: Kelly, Keith
Partner: UNT Libraries Government Documents Department

Measuring rates of outdoor airflow into HVAC systems

Description: During the last few years, new technologies have been introduced for measuring the flow rates of outside air into HVAC systems. This document describes one particular technology for measuring these airflows, a system and a related protocol developed to evaluate this and similar measurement technologies under conditions without wind, and the results of our evaluations. We conclude that the measurement technology evaluated can provide a reasonably accurate measurement of OA flow rate over a broad range of flow, without significantly increasing airflow resistance.
Date: October 1, 2002
Creator: Fisk, William J.; Faulkner, David; Sullivan, Douglas P. & Delp, Woody
Partner: UNT Libraries Government Documents Department

Advanced Strategy Guideline: Air Distribution Basics and Duct Design

Description: This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings. Principles discussed that will maximize occupant comfort include delivery of the proper amount of conditioned air for appropriate temperature mixing and uniformity without drafts, minimization of system noise, the impacts of pressure loss, efficient return air duct design, and supply air outlet placement, as well as duct layout, materials, and sizing.
Date: December 1, 2011
Creator: Burdick, A.
Partner: UNT Libraries Government Documents Department

Energy Savings and Peak Demand Reduction of a SEER 21 Heat Pump vs. a SEER 13 Heat Pump with Attic and Indoor Duct Systems

Description: This report describes results of experiments that were conducted in an unoccupied 1600 square foot house--the Manufactured Housing (MH Lab) at the Florida Solar Energy Center (FSEC)--to evaluate the delivered performance as well as the relative performance of a SEER 21 variable capacity heat pump versus a SEER 13 heat pump. The performance was evaluated with two different duct systems: a standard attic duct system and an indoor duct system located in a dropped-ceiling space.
Date: March 1, 2014
Creator: Cummings, J. & Withers, C.
Partner: UNT Libraries Government Documents Department

Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners

Description: Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.
Date: October 1, 2008
Creator: Fisk, William; Sullivan, Douglas; Cohen, Sebastian & Han, Hwataik
Partner: UNT Libraries Government Documents Department

Truss-Integrated Thermoformed Ductwork Final Technical Report

Description: This report summarizes a multi-year research effort to develop a leak-free duct system that can be readily installed within the thermal envelope. There are numerous efforts underway to improve duct system efficiency. Most of these involve modifications to current technology such as air sealing techniques like mastic and aeroseal, snap together duct connections, and greater levels of insulation. This project sought to make a more significant stride forward by introducing a duct system of a material that can be more readily sealed and can exhibit lower friction losses. The research focused on the use of smooth internal surface, low friction plastic ducts that could be easily installed with very low air leakage. The initial system concept that was proposed and researched in Phase I focused on the use of thermoformed plastic ducts installed in a recessed roof truss underneath the attic insulation. A bench top thermoformed system was developed and tested during Phase I of the project. In Phase II, a first generation duct system utilizing a resin impregnated fiberglass duct product was designed and specified. The system was installed and tested in an Atlanta area home. Following this installation research and correspondence with code officials was undertaken to alleviate the continued concern over the code acceptance of plastic ducts in above ground applications. A Committee Interpretation response was received from the International Code Council (ICC) stating that plastic ducts were allowed, but must be manufactured from materials complying with Class 0 or Class 1 rating. With assurance of code acceptance, a plastic duct system using rotomolded high density polyethylene ducts that had passed the material test requirements by impregnating the material with a fire retardant during the molding process was installed in the basement of a new ranch-style home in Madison, WI. A series of measurements to evaluate the ...
Date: August 30, 2007
Creator: Winter, Steven; Griffiths, Dianne & Gorthala, Ravi
Partner: UNT Libraries Government Documents Department

Measure Guideline: Ventilation Cooling

Description: The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.
Date: April 1, 2012
Creator: Springer, D.; Dakin, B. & German, A.
Partner: UNT Libraries Government Documents Department

A Guide to Building Commissioning

Description: Commissioning is the process of verifying that a building's heating, ventilation, and air conditioning (HVAC) and lighting systems perform correctly and efficiently. Without commissioning, system and equipment problems can result in higher than necessary utility bills and unexpected and costly equipment repairs. This report reviews the benefits of commissioning, why it is a requirement for Leadership in Energy and Environmental Design (LEED) certification, and why building codes are gradually adopting commissioning activities into code.
Date: September 1, 2011
Creator: Baechler, Michael C.
Partner: UNT Libraries Government Documents Department

Exterior Rigid Foam Insulation at the Edge of a Slab Foundation, Fresno, California (Fact Sheet)

Description: Exterior rigid foam insulation at the edge of the slab foundation was a unique feature for this low-load, unoccupied test house in a hot-dry climate and may be more appropriate for climates with higher heating loads. U.S. Department of Energy Building America research team IBACOS worked with National Housing Quality Award winner Wathen-Castanos Hybrid Homes, Inc., to assess the performance of this feature in a single-family detached ranch house with three bedrooms and two full bathrooms constructed on a slab-on-grade foundation in Fresno, California. One challenge during installation of the system was the attachment of the butyl flashing to the open framing. To solve this constructability issue, the team added a nailer to the base of the wall to properly attach and lap the flashing. In this strategy, R-7.5, 1.5-in.-thick extruded polystyrene was installed on the exterior of the slab for a modeled savings of 4,500 Btu/h on the heating load.
Date: October 1, 2013
Partner: UNT Libraries Government Documents Department

Demonstration of Datacenter Automation Software and Hardware (DASH) at the California Franchise Tax Board

Description: Control software and wireless sensors designed for closed-loop, monitoring and control of IT equipment's inlet air temperatures in datacenters were evaluated and tested while other datacenter cooling best practices were implemented. The controls software and hardware along with each best practice were installed sequentially and evaluated using a measurement and verification procedure between each measure. The results show that the overall project eliminates 475,239 kWh per year, which is 21.3percent of the baseline energy consumption of the data center. The total project, including the best practices will save $42,772 per year and cost $134,057 yielding a simple payback of 3.1 years. However, the control system alone eliminates 59.6percent of the baseline energy used to move air in the datacenter and 13.6percent of the baseline cooling energy, which is 15.2percent of the baseline energy consumption (see Project Approach, Task 1, below, for additional information) while keeping temperatures substantially within the limits recommended by ASHRAE. Savings attributed to the control system are $30,564 per year with a cost $56,824 for a simple payback of 1.9 years.
Date: December 18, 2009
Creator: Bell, Geoffrey C. & Federspiel, Clifford
Partner: UNT Libraries Government Documents Department

Homeowner Best Practices Guide for Residential Retrofits

Description: This best practices guide for HV AC system retrofits is aimed at homeowners who want guidance on upgrading their heating, cooling and ventilation (HVAC) systems and integrating these upgrades with other changes to their home. It has been developed around the idea of having packages of changes to the building HV AC system and building envelope that are climate and house construction dependent. These packages include materials procedures and equipment, and are designed to remove some of the guesswork when selecting a builder, contractor, or installer. The packages are not meant to be taken as rigid requirements - instead they are systems engineered guidelines that form the basis for energy efficient retrofits. Similar approaches have been taken previously for new construction, where a systems engineering approach has been used to develop extremely energy-efficient homes that are comfortable safe and durable, and often cost less than standard construction. This approach is best epitomized by the Building America program, whose partners have built thousands of residences throughout the U.S. using these principles. The differences between retrofitting and new construction tend to limit the changes one can make to a building, so these packages rely on relatively simple and non-intrusive technologies and techniques. The retrofits also focus on changes to a building that will give many years of service to the occupants. Another key aspect of these best practices is that we need to know how a house is working so that we know what parts have the potential for improvement. To do this we have put together a set of simple tests that a homeowner can perform on their own together with checklists and questionnaires. The measured test results, observations and homeowner answers to questions are used to direct us towards the best retrofits applicable to each individual house. The retrofits will ...
Date: September 1, 2005
Creator: Walker, Iain S.
Partner: UNT Libraries Government Documents Department

Characterizing Indoor Airflow and Pollutant Transport using Simulation Modeling for Prototypical Buildings. I. Office Buildings

Description: This paper describes the first efforts at developing a set of prototypical buildings defined to capture the key features affecting airflow and pollutant transport in buildings. These buildings will be used to model airflow and pollutant transport for emergency response scenarios when limited site-specific information is available and immediate decisions must be made, and to better understand key features of buildings controlling occupant exposures to indoor pollutant sources. This paper presents an example of this approach for a prototypical intermediate-sized, open style, commercial building. Interzonal transport due to a short-term source release, e.g., accidental chemical spill, in the bottom and the upper floors is predicted and corresponding HVAC system operation effects and potential responses are considered. Three-hour average exposure estimates are used to compare effects of source location and HVAC operation.
Date: June 1, 1999
Creator: Sohn, M.D.; Daisey, J.M. & Feustel, H.E.
Partner: UNT Libraries Government Documents Department

Best Practice for Energy Efficient Cleanrooms: Fan-FilterUnits

Description: The HVAC systems in cleanrooms may use 50 percent or more of the total cleanroom energy use. Fan energy use accounts for a significant portion (e.g., over 50%) of the HVAC energy use in cleanrooms such as ISO Classes 3, 4, or 5. Three types of air-handling systems for recirculating airflows are commonly used in cleanrooms: (1) fan-tower systems with pressurized plenum, (2) ducted HEPA systems with distributed-fans, and (3) systems with fan-filter units. Because energy efficiency of the recirculation systems could vary significantly from system type to system type, optimizing aerodynamic performance in air recirculation systems appears to be a useful approach to improve energy efficiency in cleanrooms. Providing optimal airflows through careful planning, design and operation, including air change rate, airflow uniformity, and airflow speed, is important for controlling particle contamination in cleanrooms. In practice, the use of fan-filter units (FFUs) in the air-handling system is becoming more and more popular because of this type of system may offer a number of advantages. Often modular and portable than traditional recirculation airflow systems, FFUs are easier to install, and can be easily controlled and monitored to maintain filtration performance. Energy efficiency of air handling systems using fan-filter units can, however, be lower than their counterparts and may vary significantly from system to system because of the difference in energy performance, airflow paths, and the operating conditions of FFUs.
Date: June 15, 2005
Creator: Xu, Tengfang
Partner: UNT Libraries Government Documents Department

Air Distribution Effectiveness for Different MechanicalVentilation Systems

Description: The purpose of ventilation is to dilute indoor contaminants that an occupant is exposed to. In a multi-zone environment such as a house, there will be different dilution rates and different source strengths in every zone. Most US homes have central HVAC systems, which tend to mix conditions between zones. Different types of ventilation systems will provide different amounts of dilution depending on the effectiveness of their air distribution systems and the location of sources and occupants. This paper will report on work being done to both model the impact of different systems and measurements using a new multi-tracer measurement system that has the capacity to measure not only the flow of outdoor air to each zone, but zone-to-zone transport. The ultimate objective of this project is to determine the effectiveness of different systems so that appropriate adjustments can be made in residential ventilation standards such as ASHRAE Standard 62.2.
Date: August 1, 2007
Creator: Sherman, Max H. & Walker, Iain S.
Partner: UNT Libraries Government Documents Department