Papers by Darryl Dickerhoff
Energy and Buildings, 2000
Air flowing through a supply duct infiltrates perviously faced, porous, internal duct insulation,... more Air flowing through a supply duct infiltrates perviously faced, porous, internal duct insulation, degrading its thermal performance. Encapsulating the insulation's air-facing surface with an impervious barrier prevents infiltration, increasing the capacity of the conditioned supply air to heat or cool the space to which it is delivered.
Component Leakage Testing in Residential Buildings DJ Dickerhoff, DT Grimsrud and RD Lipschutz En... more Component Leakage Testing in Residential Buildings DJ Dickerhoff, DT Grimsrud and RD Lipschutz Energy and Environment Division Lawrence Berkeley Laboratory University of California Berkeley, CA 94720 ABSTRACT The common approach to leakage area measurements ...
Lawrence Berkeley National Laboratory, Jul 13, 2010
This project evaluated the air leakage and electric power consumption of Residential HVAC compone... more This project evaluated the air leakage and electric power consumption of Residential HVAC components, with a particular focus on air leakage of furnace cabinets. Laboratory testing of HVAC components indicated that air leakage can be significant and highly variable from unit to unit ? indicating the need for a standard test method and specifying maximum allowable air leakage in California State energy codes. To further this effort, this project provided technical assistance for the development of a national standard for Residential HVAC equipment air leakage. This standard is being developed by ASHRAE and is called "ASHRAE Standard 193P -Method of test for Determining the Air Leakage Rate of HVAC Equipment". The final part of this project evaluated techniques for measurement of furnace blower power consumption. A draft test procedure for power consumption was developed in collaboration with the Canadian General Standards Board: CSA 823 "Performance Standard for air handlers in residential space conditioning systems".
The Effect of a Cool-Coating on the Thermal Effectiveness ofExposed Exterior Ducts
Energ Bldg, 2005
Rooftop air conditioning units are predominantly used for air conditioning of small- and medium-s... more Rooftop air conditioning units are predominantly used for air conditioning of small- and medium-sized commercial buildings. The majority of these rooftop units are all-air systems, using ducts to deliver conditioned air. One source of inefficiency in the delivery of the conditioned air through the rooftop ducts is thermal losses by conduction heat gains through exposed ducts. Most existing ducts are made from bare metal sheets. The daytime peak surface temperature of a rooftop bare metal sheet duct can be as much as 35-40 K warmer than that ambient air. Using sheet metals that are painted white (in a new installation) or coating the existing exposed ducts (in a retrofit application) lowers the duct surface temperature, reducing the heat conducted into the ducts and hence improving the delivery effectiveness of the duct system. To investigate the effect of increasing the solar reflectance of a duct to reduce conduction heat gains through the duct shell, we measured in three duct systems supply air temperatures at the inlet of the duct and close to the point of delivery into the conditioned space. In one system, coating the ducts with a white paint decreased the average conduction heat gain by about 0.64 MJ/day/m2 of coated duct surface area, improving the delivery effectiveness by 2%. In the other two systems, the reduction in the conduction heat gain was about 0.34-0.46 MJ/day/m² and the delivery effectiveness improved by about 5-10%.
Case study of environmental protection agency (EPA) region 8 headquarters building
Center For the Built Environment, 2008
Author: Webster, Tom, Center for the Built Environment, University of California, Berkeley Bauman... more Author: Webster, Tom, Center for the Built Environment, University of California, Berkeley Bauman, Fred, Center for the Built Environment, University of California, Berkeley Dickerhoff, Darryl J, Lawrence Berkeley National Laboratory Lee, Yoon Soo, Center for the Built ...
Project report: field testing of wind cooling effects on Navy buildings
Technical Report on California State Teachers Retirement System Building: UFAD Performance and Blinds Study
Lawrence Berkeley National Laboratory, Aug 1, 2000
Duct leakage has been identified as a major source of energy loss in residential buildings. Most ... more Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have shown that these seals tend to fail over time periods ranging from days to years. We have used several test methods over the last few years to evaluate the longevity of duct sealants when subjected to temperatures and pressures representative of those found in the field. Traditional cloth duct tapes have been found to significantly under-perform other sealants and have been banned from receiving duct tightness credits in California's energy code (California Energy Commission 1998). Our accelerated testing apparatus has been redesigned since its first usage for improved performance. The methodology is currently under consideration by the American Society for Testing and Materials (ASTM) as a potential new test method. This report will summarize the set of measurements to date, review the status of the test apparatus and test method, and summarize the applications of these results to codes and standards.
Evaluation of PEGIT duct connection system
Lawrence Berkeley National Laboratory, Aug 1, 2003
Most air duct system components are assembled in the field and are mechanically fastened by sheet... more Most air duct system components are assembled in the field and are mechanically fastened by sheet metal screws (for sheet metal-to-sheet metal) or by drawbands (for flex duct-to-sheet metal). Air sealing is separate from this mechanical fastening and is usually achieved using tape or mastic products after mechanical fastening. Field observations have shown that mechanical fastening rarely meets code or manufacturers requirements and that sealing procedures are similarly inconsistent. To address these problems, Proctor Engineering Group (PEG) is developing a system of joining ducts (called PEGIT) that combines the mechanical fastening and sealing into a single self-contained procedure. The PEGIT system uses a shaped flexible seal between specially designed sheet metal duct fittings to both seal and fasten duct sections together. Figure 1 shows the inner duct fitting complete with rubber seal. This seal provides the air seal for the completed fitting and is shaped to allow the inner and outer fittings to slide together, and then to lock the fittings in place. The illustration in Figure 2 shows the approximate cross section of the rubber seal that shows how the seal has a lip that is angled backwards. This angled lip allows the joint to be pushed together by folding flat but then its long axis makes it stiff in the pulling apart direction. This study was undertaken to assist PEG in some of the design aspects of this system and to test the performance of the PEGIT system. This study was carried out in three phases. The initial phase evaluated the performance of a preliminary seal design for the PEGIT system. After the first phase, the seal was redesigned and this new seal was evaluated in the second phase of testing. The third phase performed more detailed testing of the second seal design to optimize the production tolerances of the sheet metal fittings. This report summarizes our findings from the first two phases and provides details about the third phase of testing.
Low flow fume hood
A fume hood is provided having an adequate level of safety while reducing the amount of air exhau... more A fume hood is provided having an adequate level of safety while reducing the amount of air exhausted from the hood. A displacement flow fume hood works on the principal of a displacement flow which displaces the volume currently present in the hood using a push-pull system. The displacement flow includes a plurality of air supplies which provide fresh air,
Room air stratification (RAS) is one of the key features of UFAD technology that determines how t... more Room air stratification (RAS) is one of the key features of UFAD technology that determines how the benefits of low energy, good indoor comfort and ventilation performance are achieved. Understanding, accounting for, and controlling RAS are essential to successful design, installation, and operation of these systems. Likewise, modeling RAS is essential to simulating the energy performance of these systems. Although much research has been focused on RAS for displacement ventilation systems, relatively little has been done to develop a comprehensive model for UFAD systems, and no models currently exist within energy simulation programs commonly used by design and installation practitioners. Development of a model for RAS must be based on sound physical principles as well as also accurately representing the reality of how these systems are installed and operated. That is the purpose of the full scale testing effort we describe in this report.
In recent years, great strides have been made in reducing air leakage in residential and to a les... more In recent years, great strides have been made in reducing air leakage in residential and to a lesser extent small commercial forced air duct systems. Several authorities have introduced low leakage limits for thermal distribution systems; for example, the State of California Energy Code for Buildings gives credit for systems that leak less than 6% of the total air flow at 25 Pa. Practitioners have found that a significant barrier to meeting specifications like this is the air leakage of the furnace or air handler itself. Anecdotal evidence exists for the magnitude of the air leakage of furnaces and air handlers. The states of California and Florida include air leakage limits for the furnaces in their State Building Energy Codes. However, there is currently no standard test method for measuring this air leakage that could be used for uniform and reliable ratings. This paper presents the results of laboratory measurements air leakage testing of furnaces and air handlers. The results i...
A post-occupancy monitored evaluation of the dimmable lighting, automated shading, and underfloor air distribution system in The New York Times Building
The Delta Q method of testing the air leakage of ducts
The DeltaQ test has been developed in order to provide better estimates of forced air system air ... more The DeltaQ test has been developed in order to provide better estimates of forced air system air leakage for use in energy efficiency calculations and for compliance testing of duct systems. The DeltaQ test combines a model of the house and duct system with the results of house pressurization tests with the air handler on and off to determine the
Validating and Improving the DeltaQ Duct Leakage Test
DESCRIPTION OF THE LBL MULTITRACER MEASUREMENT SYSTEM
For the past several years LBL has been developing the MultiTracer Measurement System (MTMS )t o ... more For the past several years LBL has been developing the MultiTracer Measurement System (MTMS )t o provide full multizone air flow information in an accurate, real-time manner. MTMS is based on a qua- drapole mass spectrometer to provide high-speed concentration analysis of multiple tracer gasses in the (low) ppm level which are injected into multiple zones using mass flow controllers.
Using footwarmers in offices for thermal comfort and energy savings
Energy and Buildings, 2015
Duct leakage has been identified as a major source of energy loss in residential buildings. Most ... more Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field
The performance of air-handling systems in buildings needs to be improved. Many of the deficienci... more The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems.
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Papers by Darryl Dickerhoff