Engineering Commons^™

Lab Home Testing Of Residential Isolation Space Control To Minimize Infectious Disease Transmission In Existing Single-Family Homes, Florida Solar Energy Center, Tanvir Khan

FSEC Energy Research Center®

Existing evidence strongly suggests that viral infectious diseases can be transmitted via an airborne route across distances in indoor environments. Accordingly, the risk of airborne transmission within homes should be managed. The public health emergency associated with SARS-CoV-2 makes controlling airborne transmission of respired viruses in indoor environments critical, especially in poorly ventilated indoor environments. The effectiveness of engineering interventions requiring minor efforts that create a negative-pressure isolation zone (IZ) for a contagious person has yet to be tested for existing residential homes.

To mitigate the risk of airborne virus transmission and maximize health protection for the population in existing …

Lab Home Testing Of Residential Isolation Space Control To Minimize Infectious Disease Transmission In Existing Single-Family Homes -- Fact Sheet, Florida Solar Energy Center, Tanvir Khan

FSEC Energy Research Center®

The FSEC Energy Research Center at the University of Central Florida performed research to test the effectiveness of interventions to isolate an ill person recovering from a contagious disease in a single-family home from the rest of the occupants in the home. Focus was placed on interventions requiring minor cost and effort on the part of the occupants.

DOE/GO-102021-5537, https://www.nrel.gov/docs/fy21osti/79519.pdf

Metal And Flexible Duct Systems Impacts Upon Cooling Energy And Performance, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Flexible duct is commonly used throughout the U.S. in residential construction. It performs well when installed in accordance with industry standards, however, they are often not installed as such. Issues such as not cutting ducts to the exact length needed, and instead using significantly more duct, result in compression and higher static pressure. Poorly supported ducts or turns without proper radius also increase static pressure. A research project was completed to evaluate the differences in performance between a metal duct and flexible duct systems in two side-by-side otherwise identical residential laboratories. Testing evaluated three different flex duct system configurations compared …

Characterization Of Mechanical Ventilation Systems In New Us Homes: What Types Of Systems Are Out There And Are They Functioning As Intended?, Florida Solar Energy Center, Eric Martin

FSEC Energy Research Center®

As the airtightness of homes improves to meet energy efficiency goals, it becomes more important for mechanical ventilation systems to help maintain a comfortable and healthy indoor air environment. ASHRAE Standard 62.2 provides national guidance for mechanical ventilation system design and installation, however adoption of those guidelines into local building codes has occurred at different rates. Once provisions for mechanical ventilation are adopted in a local code, are mechanical ventilation systems properly designed, installed, commissioned and operated according to code or above-code program requirements? This paper presents results from field studies that include characterization of whole house mechanical ventilation (WHMV) …

Residential Air Leakage Testing And Mechanical Ventilation Verification, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This project is intended to answer the following four questions regarding residential building air leakage testing and whole-house mechanical ventilation requirements as stated in the 2016 Supplement 1 changes to the 5th Edition (2014) Florida Energy Conservation Code, and now continued in the 6th Edition (2017) Code: - Is the new requirement to test residential air leakage being followed? - Who is providing the air leakage testing? - Are accurate air leakage rate test values being reported? - Is whole-house mechanical ventilation being installed in applicable cases?

A Review Of Home Airtightness And Ventilation Approaches For Florida Building Commission Research, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This research project was conducted with the primary objectives of 1) providing a literature review, examination of experimental data, and calculations of energy impacts of using or not using various types of ventilation systems and 2) developing alternative approaches to achieving acceptable levels of ventilation while avoiding the risks associated with super-tight home enclosures and potential mechanical system failures. The report includes discussions of pertinent airtightness and mechanical ventilation topics and provides recommended ventilation practices for Florida.

Flexible Residential Test Facility: Impact Of Infiltration And Ventilation On Measured Cooling Season Energy And Moisture Levels, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

Opportunities For Energy Conservation And Improved Comfort From Wind Washing Retrofits In Two-Story Homes - Part I, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Wind washing is a general term referring to diminished thermal control caused by air movement over or through a thermal barrier. The primary focus of this paper is towards a specific type of wind washing where wind can push attic air into the floor cavity between first and second stories of the home through ineffective (or missing) air barriers separating attic space from the floor cavity. A second type of wind washing studied in this project involved insulation batts on knee walls where space between the batts and the wall board allowed air movement against the gypsum wall board. During …

Opportunities For Energy Conservation And Improved Comfort From Wind Washing Retrofits In Two-Story Homes - Part Ii, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Wind washing is a general term referring to diminished thermal control caused by air movement partially or completely bypassing the thermal barrier. The primary focus of this paper relates to a specific type of wind washing where wind can push attic air into the floor cavity between first and second stories of the home through ineffective (or missing) air barriers separating attic space from the floor cavity. A second type of wind washing studied in this project involves insulation batts on knee walls where space between the batts and the wall board allow air movement against the gypsum wall board. …

Investigating Solutions To Wind Washing Issues In 2-Story Florida Homes; Phase 1, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Wind washing has been identified as a potentially significant issue regarding energy, demand, comfort, and humidity in some two-story Florida homes. In its most common configuration, wind washing occurs when attic spaces over first-floor portions of the home abut the second story, and the floor cavity of the second story is open to that attic space. Wind blowing into attic vents can push hot attic air into the inter-story floor cavity, bypassing the typical thermal boundaries of the building and introducing considerable heat into the house. Wind washing can also occur when there is little or no attic involved, where …

Airflow Network Modeling In Energyplus, Florida Solar Energy Center, Lixing Gu

FSEC Energy Research Center®

The airflow network model in EnergyPlus provides the ability to simulate multizone wind-driven airflows. The model is also able to simulate the impacts of forced air distribution systems, including supply and return air leaks. The air distribution system portion of the model is currently applicable for constant-air-volume systems. Future enhancements will include adding hybrid ventilation control and possible extension to include variable-air-volume distribution systems.

This paper describes the input objects, calculation procedures, model validation, and example results. The model inputs consist of five main objects: simulation control, multizone data, node data, component data, and linkage data. The model calculates pressure …

Mitigating The Impacts Of Uncontrolled Air Flow On Indoor Environmental Quality And Energy Demand In Non-Residential Buildings, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

This project builds on previous field research in Florida that has demonstrated the significant impact that uncontrolled air flows (UAFs) have on indoor environmental quality (IEQ) and energy use in small commercial buildings, a large but poorly understood segment of the nation's building stock. The goal of this project was to extend that research to a national scale by assessing the importance of UAFs in a sample of 25 commercial buildings in New York State. The differences in climate and construction techniques between New York and Florida are expected to bound the range conditions typically found on a national basis. …

Balanced Return Air, Duct Airtightness, And Combustion/Dilution Air Code Compliance In 40 Central Florida Homes, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

This report has been extracted from a larger report titled "Florida Building Code - Enhance Florida's Building to Next-Generation Energy & Mechanical Codes and Enrich Compliance", FSEC-CR-1678-06, November 29, 2006, which can be found at http://www.fsec.ucf.edu/en/publications/pdf/FSEC-CR-1678-06.pdf

Energy Efficient Renovations Of Storm Damaged Residences - Florida Case Studies, Florida Solar Energy Center, Neil Moyer

FSEC Energy Research Center®

Storm-damaged homes offer the opportunity for repairs that reduce energy use, improve comfort and enhance resistance to future storms. Case studies of four Florida homes damaged in the summer of 2004 were documented to show the costs and benefits of various retrofit strategies. All four homes required roof replacement and each took advantage of roof cladding with higher reflectance than the original, a proven means of reducing cooling energy use. Two of the case studies included improvements to attic insulation, tightening of the envelope and/or duct system and improved efficiency equipment and lighting. Energy savings attributable to storm repairs were …

Theoretical Evaluation Of The Nightcool Nocturnal Radiation Cooling Concept, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

An evaluation has been conducted of the potential of a night sky cooling system to substantially reduce space cooling needs in homes in North American climates. The report describes the innovative residential cooling system which uses nocturnal night sky radiation from a roof integrated radiator. The system uses a sealed attic covered by a highly conductive metal roof which is selectively linked by air flow to the main zone with the attic zone to provide cooling- largely during nighttime hours. Available house mass is used to store sensible cooling. Additional dehumidification is done during the evening hours as warranted by …

Cooling Load Reduction And Air Conditioner Design In A 19th Century Florida House Museum, Florida Solar Energy Center, David Chasar

FSEC Energy Research Center®

Restoration plans at the H.S. Williams house included the installation of a space conditioning system. This contract report details how building envelope construction and air conditioner design were optimized as a system. Many aspects of the effort lent themselves to maintaining important "character-defining" features of the building including the resurrection of passive cooling attributes like light colored exterior paint and operable storm shutters. In addition, outside air infiltration was measured on the Williams house and six other balloon-frame homes to document this often significant cooling load component.

Air Handler Leakage: Field Testing Results In Residences, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing was performed to characterize air leakage in 30 air handler cabinets and at connections to supply and return ductwork. Operating pressures were measured in the air handler and plenums. Q 0.1 (Q 25) in the air handler averaged 23.9 cfm (11.3 l/s) in 30 homes. Leakage at the return and supply ductwork connections averaged 3.9 Q 0.1 (1.8 l/s Q 25) and 2.2 Q 0.1 (1.0 l/s Q 25), respectively. Actual return side leakage of 77.5 cfm (36.6 l/s) and supply side leakage of 3.1 cfm (1.5 l/s) are calculated based on Q 0.1 (Q 25) and measured operating …

Field Testing And Computer Modeling To Characterize The Energy Impacts Of Air Handler Leakage, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

In order to determine the impact of air handler location upon heating and cooling energy use, the amount of air leakage which occurs in the air handler cabinet needs to be known. Also, the leakage which occurs at the connections between the air handler cabinet and the return and supply plenums needs to be known as well because these connection leaks would also be located in the attic or any other location.

In order to assess this leakage, testing was performed on a total of 69 air conditioning systems. Thirty systems were tested in the year 2001 under funding from …

Evaluating The Impacts Of Uncontrolled Air Flow And Hvac Performance Problems On Florida's Commercial And Institutional Buildings - Final Report, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Twenty commercial and institutional buildings located in central Florida were tested for uncontrolled air flow and cooling system problems. Tested buildings were selected based on three criteria; 1) buildings with large exhaust fans, 2) buildings with leaky ceilings, and 3) education buildings. They ranged in size from a 650 square foot portable classroom to a 50,000 square foot elementary school, with an average floor area of 6518 square feet.

Diagnostic inspection and testing was performed in each building to identify problems related to uncontrolled air flow or HVAC system or control problems. The tests were performed to characterize or identify …

Building Envelope Air Leakage Failure In Small Commercial Buildings Related To The Use Of Suspended Tile Ceilings, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Recent research over the last few years is providing a better understanding about the building envelope of small commercial buildings. These buildings have very similar construction to single-family residential buildings, but unlike residential buildings, they usually have a suspended tile ceiling between the conditioned space and ceiling or attic space. Testing indicates that the building envelope in small commercial buildings is substantially less airtight than residential buildings and the cause is associated with the suspended ceiling. Ceiling airtightness test results from two buildings are presented in this paper and show that they are very leaky. The pathways in the ceiling …

Ventilation, Humidity, And Energy Impacts Of Uncontrolled Airflow In A Light Commercial Building, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

A small commercial building was monitored before and after energy saving retrofits to study the impact of retrofits upon ventilation rates, humidity, building pressure and air conditioning energy use. Duct airtightness testing identified severe duct leakage as a significant source of uncontrolled airflow. Differential pressure and infiltration measurements using tracer gas indicated an attic exhaust fan as another significant source of uncontrolled airflow. Duct repair resulted in a 31% drop (30.5 kWh/day) in cooling energy, and an increase in relative humidity from 72% to 76%. Turning off the attic exhaust resulted in an additional 36% energy savings (14.3 kWh/day), including …

Standards And Verification Protocols For Commissioning Air Flows In Buildings, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Commissioning involves three major elements - 1) process, 2) standards, and 3) protocols to verify compliance with the standards. Process is the step-by-step oversight of and involvement in the design, build, and start-up of the facility, to make sure that the design matches the customer's needs, that the design is consistent with good building science practice, that construction matches the construction documents, and that systems and system interactions are properly tested at start-up. This paper does not address process, rather it focuses on the second and third elements -- standards and compliance protocols. It presents standards related to airtightness, air …

Building Cavities Used As Ducts: Air Leakage Characteristics And Impacts In Light Commercial Buildings, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Field testing in 70 small commercial buildings in central Florida identified that building cavities were used as part of the air distribution system in 33 buildings. The various building cavity types (# of buildings in parentheses) are: enclosed air handler support platforms (10), mechanical closets (8), mechanical rooms (6), ceiling spaces (7), wall cavities (6), chases (1), and "other" building cavities (2). Testing found that these building cavities are considerably more leaky than standard ducts and plenums because they are generally not built to the same airtightness standard as ducts. Actual air leakage is a function not only of duct …

Identifying Air Flow Failure Modes In Small Commercial Buildings: Tools And Methodologies For Building Commissioning Diagnostics, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

A recent study of small commercial buildings in central Florida found that uncontrolled air flow -- including duct leakage, return air imbalance, and exhaust air/make-up air imbalance -- is widespread. Of 70 buildings studied, only 1 was identified as having no significant uncontrolled air flow. The causes of uncontrolled air flow include failure of design, poor workmanship, O&M problems, HVAC commissioning failures, materials degradation, and building retrofits. This study also found that the consequences of uncontrolled air flow are often quite severe and varied -- including high utility bills, occupant thermal discomfort, high humidity, mold and mildew growth, moisture damage …

Field Measurement Of Uncontrolled Air Flow And Depressurization In Restaurants, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Field investigations were done in seven restaurants (subsample of a 63 commercial buildings study) to identify uncontrolled air flows and pressure imbalances. Testing included building airtightness tests, identification of building air barrier location, duct system airtightness, characterization of pressure differentials, building air flow balance, and infiltration/ventilation rates. All restaurants were found to operate at negative pressures which ranged from -0.003 inWC (-0.8 Pa) to -0.173 inWC (-43 Pa) and averaged -0.051 inWC (-12.7 Pa) under normal operation. The variables which affect depressurization are large exhaust fans, missing or undersized make-up air, intermittent outdoor air caused by the cycling of air …

Uncontrolled Air Flow In Non-Residential Buildings, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

The objective of this study was to develop the capability to substantially reduce energy use, building degradation and indoor air pollution caused by uncontrolled air flow in nonresidential buildings. For purposes of the study, 'uncontrolled air flow' was defined as air moving across the building envelope or between zones or components of a building, where the pathways of flow, the direction of flow, and the origin of the air are unknown, unspecified, or unintended. The study comes to three major conclusions as follows: 1. Uncontrolled air flow is pervasive in buildings, often resulting in severe -- and sometimes even catastrophic …

Energy Savings From Repair Of Uncontrolled Airflow In Eighteen Small Commercial Buildings, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

Uncontrolled airflow, including duct leakage, pressure imbalances caused by closed interior doors, and exhaust/intake airflow imbalance, was characterized in 70 commercial buildings. In 18 of these buildings, uncontrolled airflows were repaired and energy savings from these repairs were monitored. In most buildings the retrofit was duct repair. In other cases, outdoor airflow was reduced and return air transfers were provided. Cooling energy use was reduced by an average 15.1% in these 18 buildings. With an average repair cost of $455 and average cooling energy savings of $195 per year, uncontrolled airflow retrofits proved to be very cost-effective. Various factors indicate …

Indoor Air Quality Impacts Of Uncontrolled Air Flow And Depressurization In Eight Commercial Buildings In Central Florida, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Field investigations were done in 68 commercial buildings to identify uncontrolled air flows and pressure imbalances. Results from eight buildings (six restaurants and two sports facilities) are reported in this paper. Testing included building airtightness tests, identification of building air barrier location, duct system airtightness, characterization of pressure differentials, building air flow balance, and infiltration/ventilation rates. Six restaurants and one sports facility were found to operate at negative pressures which ranged from -0.003 inWC (-0.8 Pa) to -0.173 inWC (-43 Pa) and averaged -0.051 inWC (-12.7 Pa) under normal operation. A second sports facility operates partially at positive pressure and …

Investigation Of Air Distribution System Leakage And Its Impacts In Central Florida Homes, Florida Solar Energy Center

FSEC Energy Research Center®

Testing for air leakage in air distribution systems was done in 160 central Florida homes. Tracer gas tests found that infiltration rates were three times greater when the air handler was operating that when it was off, indicating that there are large leaks in the air distribution system. Infiltration averaged 0.91 air changes per hour (ach) with the air handler (AH) operating continuously and 0.28 ach with the AH off. Return leaks were measured by tracer gas and found to average 10.7% of AH total flow. House airtightness, in 99 of these homes, determined by blower door testing, averaged 12.7 …

Impacts Of Duct Leakage On Infiltration Rates, Space Conditioning Energy Use, And Peak Electrical Demand In Florida Homes, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing for duct leakage was done in 91 homes. Tracer gas tests found that infiltration rates were four times greater when the air handler was operating than when it was off. Return leaks were found to average 10.0% of air handler total flow. House airtightness, in 63 of these homes, determined by blower door testing, averaged 12.38 air changes per hour at 50 Pascals (ACH50). When the duct registers were sealed, ACH50 decreased to 10.93, indicating that 11.7% of the house leaks were in the duct system.

Duct repairs were made on 25 homes. Blower door tests found 12.30 air …