Tech Update

AHRI’s TechUpdate e-newsletter is published three times a year and includes the latest information on AHRI’s research initiatives, including recently concluded research reports and ongoing projects.

The AHRI Research Program supports AHRI’s advocacy positions, standards program, and certification program. It is a pre-competitive, basic research program that provides AHRI members with the scientific knowledge and design tools needed for the development of the next generation of energy efficient, environmentally-friendly HVACR equipment.

The AHRI Research and Technology Committee administers the program. The Committee recommends and takes measures to promote research activities and provides guidance and direction to staff concerning research and technology programs of AHRI. AHRI research projects are funded and managed entirely by AHRI or one or more of its product sections. AHRI closely works with ASHRAE to leverage its program by co-funding with ASHRAE on projects that are of interest to AHRI members. Final reports are made available on AHRI’s website.

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December 2015


Click here to download a PDF version of the December 2015 TechUpdate.

AHRI Begins Flammable Refrigerants Research Initiative

Due to environmental and regulatory concerns, the industry is transitioning to low-GWP refrigerants, which are mildly flammable. In order to address this issue, the AHRI Research and Technology (R&T) established a Flammable Refrigerants Subcommittee to determine the knowledge gaps in existing flammable refrigerant research, and to develop a roadmap with priorities and a timeline to complete research for the safe use of flammable refrigerants, focusing on 2L refrigerants. Through this effort, the subcommittee will facilitate key research, deliver scientific findings, and produce publicly available and technically sound references to support code and standard activities related to the use of flammable refrigerants.

As part of this effort, the subcommittee surveyed relevant committees and working groups currently working on codes and standards activities, and identified and prioritized key research needs. The prioritization was based on the importance and urgency of a particular research need. The initial phase will require $4.6 million to fund high priority projects. AHRI has committed to provide up to $1 million for this collaborative research effort, and is actively seeking additional sponsors.

AHRI Low-GWP AREP Phase II Testing Nears Completion

AHRI’s Low-Global Warming Potential Alternative Refrigerants Evaluation Program (Low-GWP AREP) Phase II testing is nearly complete. In Phase II, 28 refrigerant candidates were tested by 22 test entities worldwide. The testing covered a variety of products, including air conditioners, heat pumps, chillers, ice makers, and commercial refrigeration displace cases. Phase II testing also included performance testing under high ambient conditions up to 125°F. Phase II is expected to produce around 32 test reports, which are available at www.ahrinet.org/AREP. AHRI will host its Low-GWP AREP II Conference on January 21, 2016, at the Rosen Centre Hotel in Orlando, Fla., one day before the start of the ASHRAE Winter Conference.

Recently Published Research Reports

AHRI published the final report for AHRI-8013: A Study of Methods to Represent Compressor Performance Data Over an Operating Envelope Based on a Finite Set of Test Data. This project had two objectives:(1) to determine the optimal method to represent performance data over the application envelope, which maximizes accuracy for a given number of test points; and (2) to develop an estimate of the level of uncertainty in the each method as a function of measurement reproducibility and/or product-to-product variation, especially at the typical rating points given in the performance rating standard. The report is available to the public online here.

The AHRTI co-sponsored ASHRAE 1467-RP, Balancing Latent Heat Load between Display Cases and Store Comfort Cooling, was published by ASHRAE. The overall objective of this project is to provide a comprehensive assessment of the potential for energy savings in supermarkets by optimized design and operation of the combined HVAC and refrigeration systems. The assessment included the effects of climate, space temperature and humidity set-point controls, HVAC system type and characteristics, and the design and operation of the refrigerated cases. The final report can be accessed by AHRI members either through the ASHRAE website, or through AHRI upon request.

New AHRI Research Project on Ignition Sources Energy

AHRI awarded its new project AHRI-8017: Study on Ignition Sources Energy, to the University of Maryland’s Department of Fire Protection Engineering. The project’s goal is to evaluate energy produced by potential ignition sources in residential applications relative to minimum ignition energy from a list of A2L refrigerants, and to investigate the likelihood of the presence of ignition sources and refrigerant ignition. The results could be used to expand the existing risk assessment studies of A2L refrigerants by providing further detail.

Additional Research Activities

Department of Energy Building Technologies Office Workshop on New Advanced R&D Effort
The Department of Energy Building Technologies Office is exploring the launch of a major research effort dedicated to advanced HVACR technologies, and hosted a workshop on December 8 at ASHRAE headquarters in Atlanta, Ga. AHRI staff attended the workshop and exchanged ideas on the technical focus and overall structure and approach of the project.

The guiding vision of this R&D effort is a future in which high-global warming potential refrigerants are eliminated from HVACR technologies while energy efficiency is improved. By engaging key stakeholders at the workshop, BTO gathered input on next-generation technology development priorities, as well as management structure and organizational approaches.

Forum on Alternative Refrigerants for High Ambient Countries
AHRI staff presented papers at the Forum on Alternative Refrigerants for High-Ambient Countries in Dubai on October 31. Focused on equipment and refrigerant use in places with high ambient temperatures, the forum was organized by the United Nations Environment Programme, the Emirates Authority for Standards & Metrology, the United Nations Industrial Development Organization, and ASHRAE’s Falcon Chapter.

AHRI President and CEO Stephen Yurek delivered a keynote address. Yurek stressed the need for timely, but not hasty, actions regarding the adoption of alternative refrigerants. AHRI Senior Vice President of Regulatory Policy and Research Karim Amrane reported on the AHRI Low-Global Warming Potential Alternative Refrigerants Evaluation Program, and Vice President of International Affairs Jim Walters moderated a panel on future refrigerant work and possible outcomes.

24th IIR International Congress of Refrigeration
AHRI staff attended the 24th IIR International Congress of Refrigeration at Yokohama, Japan, and provided details on AHRI’s low-GWP research. They also participated in a workshop on Risk Assessment of Mildly Flammable Refrigerants, and discussed AHRI’s activities related to risk assessment for mildly flammable refrigerants. The workshop shared new details on research underway throughout the industry, academia, and government in Japan and other countries.

Ongoing Research Projects Cover Wide Range of Products

AHRI’s research projects often take several months or even years to complete. The following projects are ongoing this year.

AHRI-8011: Field Evaluation for Combustion Appliance Auditing. The tasks of this project will be to: identify currently recognized or commonly utilized procedures for evaluating the safety and performance of installed combustion equipment; compare and contrast those procedures; and provide information either to identify the correct procedure or to develop such a procedure if none of the existing ones are sufficiently correct. The project is ongoing at Gas Consultants, Inc., and expected to be completed in early 2016.

AHRI-8012: Developing Fan Power Terminal Unit Performance Data and Models Compatible with EnergyPlus. This project will develop a broad range of fan/motor efficiency data that can be readily used in EnergyPlus. Models for alternative configurations/operations of series and parallel units will be developed. A leakage model is planned to be incorporated into the EnergyPlus model. The project is ongoing at Baylor University and expected to be completed in July 2016.

AHRI-8014: The Effect of Lower Return Air Temperatures on Furnace Heat Exchangers. Furnace installation manuals limit the return air temperature to 55 or 60°F, but many thermostats have the ability to regulate to as low as 40°F. Low return air temperatures may compromise the life and robustness of heat exchangers. This project will establish what return air temperature is appropriate to avoid unnecessary stress on the heat exchanger. It will also establish guidelines for set back and extended absence set points to allow maximum energy savings while preserving heat exchanger integrity. The project is ongoing at Gas Consultants, Inc., and expected to be completed in early 2016.

AHRI-8016: Risk Assessment for Rooftop Units Using A2L Refrigerants. The objective of this project is to use fault tree analysis to conduct refrigerant ignition risk assessment for rooftop units using A2L flammable refrigerants. The scope of the risk assessment is to evaluate the refrigerant ignition risks during operation and service from using HFC-32 (GWP of 675) or HFO-1234yf (GWP of 4), or HFO-1234ze (GWP of 6) in rooftop units. The project is ongoing at Navigant Consulting, Inc. and expected to be completed in early 2016.

AHRI-8018: Review of Refrigerant Recycling Programs. The objective of this project is to conduct a literature survey and to interview key personnel to identify the types of refrigerant recycling programs implemented in different regions of the world, and evaluate how successful/effective these programs/regulations have been compared to those in the U.S. The result of the research will provide guidance on estimating refrigerant emissions during the end of life recycling process. The project report will be available in early 2016.

AHRI/ASHRAE Co-funded Projects Leverage AHRI Resources, Benefit Members

AHRI works closely with ASHRAE to leverage the AHRI research program by co-funding with ASHRAE on projects that are of AHRI members’ interest, some of which are listed below. All AHRI co-funded ASHRAE project final reports are available to AHRI members upon request.

Ongoing ASHRAE Projects:

AHRTI-ASHRAE-1507: Binary Refrigerant Flame Boundary. The project aims to develop, through a literature search, a database of past pertinent binary flame boundary concentrations, and to determine, through laboratory measurements, values for 10 additional refrigerant component pairs of commonly used and newly introduced flammable/nonflammable refrigerants pairs. The project is completed, and the final deliverable is being prepared.

AHRTI-ASHRAE-1535: A Heat Transfer and Friction Factor Correlation for Low Air-Side Reynolds Number Applications of Compact Heat Exchangers. The objective of this research is to develop airside heat transfer and pressure drop correlations for high performance compact heat exchangers under low-air velocity conditions. The project is ongoing at Florida International University.

AHRI-ASHRAE-1630: Update the Scientific Evidence for Specifying Lower Limit Relative Humidity Levels for Comfort, Health and IEQ in Occupied Spaces. The objectives of this project are to determine and quantify the effect of low humidity (RH≤40%) on comfort, health, and indoor environmental quality in residences and non-industrial workplaces. The project is ongoing at Kansas State University.

AHRTI-ASHRAE-1634: Guide for Sustainable Refrigerated Facilities and Refrigeration Systems. The objective of the project is to develop a guide for sustainable refrigerated facilities and refrigeration systems. Information in the guide will be used for the design of new facilities, expansions, and remodels, as well as provide guidance on improvements and operating methods that may also be applied to existing facilities. This project is ongoing at Massey University.

AHRTI-ASHRAE-1641: Effect of Unsaturated Fluorocarbon Contaminants on the Reliability and Performance of HVACR Equipment. This project aims at developing chemical reactivity information on unsaturated fluorocarbon contaminants to help the HVACR industry understand its impact on the performance and reliability of products. The results from this work will advance knowledge to support the HVACR industry in revising the limits for unsaturated compounds in various refrigerants in operating equipment, as well as new and reclaimed refrigerants. This project is ongoing at Spauschus Associates.

AHRTI-ASHRAE-1645: Development of New Accelerated Corrosion Tests for All-Aluminum Microchannel and Tube and Fin Heat Exchangers. The objective of this research is to develop a new corrosion test, or justify the use of an existing standardized accelerated test, for both all-aluminum tube and fin and brazed microchannel heat exchangers. This project is ongoing at University of Northern Texas.

AHRTI-ASHRAE-1717: Improve Accuracy and Reproducibility of ASTM-E681 Test Method for Flammability Limit Measurement of 2L Flammable Refrigerants. The project will identify modifications needed for testing new alternative refrigerants for flammability following ASTM E681 to allow ASHRAE SSPC 34 to properly identify their safety classification for use by the industry. The project is ongoing at University of Maryland.