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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May 2015

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

Two Reports Now Available for Phase II of AHRI's Low-GWP AREP

AHRI's Low-Global Warming Potential Alternative Refrigerants Evaluation Program (Low-GWP AREP) Phase II testing is ongoing. In Phase II, 15 new low GWP refrigerant candidates were selected for testing by 22 test entities globally. Twelve compressors are being tested in Phase II, as well as 14 air-conditioning products, including air-conditioners, heat pumps, roof top units, and water chillers. Phase II also includes testing of five refrigeration products. Eight test plans include equipment performance testing under high ambient conditions.

Seven test companies have submitted their test reports for review. Two reports have been made available to the public. The remaining test reports are being prepared and are expected to be available this fall. The approved test reports are online here.

Under Phase II testing, AHRI is collaborating with the White House Council on Environmental Quality and the Oak Ridge National Laboratory to conduct mini-split unit high ambient condition tests using low GWP refrigerants. This effort is to support proposed amendments to the Montreal Protocol.

AHRI Establishes Flammable Refrigerants Subcommittee

The AHRI Research and Technology (R&T) established a Flammable Refrigerants Subcommittee to determine gaps in existing flammable refrigerant research and develop a roadmap to complete critical research for the safe use of flammable refrigerants. The roadmap will include priorities and a timeline, and will focus 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. The Subcommittee will gather input on existing issues and research needs via a survey of committees and working groups (WG) addressing codes and standards related to the use of flammable refrigerants. The Subcommittee is focused specifically on research efforts for flammable refrigerants and will not address policy, codes and standards issues, or regulatory actions. Such activities will be addressed by other relevant AHRI Committee(s).

Four New Research Reports Now Available

AHRI recently completed research project 8013, A Study of Methods to Represent Compressor Performance Data Over an Operating Envelope Based on a Finite Set of Test Data. The final report is available for AHRI members only here. The 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.

AHRI also published the final reports of the following research projects. The reports are available to the public on the AHRI website:

AHRI-8009: Risk Assessment of Refrigeration Systems Using A2L Flammable Refrigerants.
The objective of this project is to use fault tree analysis to conduct risk assessment for small commercial refrigeration equipment using A2L flammable refrigerants. The scope of the risk assessment is to evaluate risks during the operation and service of HFC-32 (GWP of 675), HFO-1234yf (GWP of 4), or HFO-1234ze (GWP of 6) in a self-contained reach-in cooler and a single condensing unit connected to refrigeration unit(s). Three location scenarios were evaluated: a small restaurant kitchen, a lunch counter, and a convenience store. The work also included Computational Fluid Dynamics (CFD) modeling and experimental measurements on the refrigerant dispersion pattern. The FTA in this study only considered refrigerant ignition and did not determine whether a fire would ensue due to the ignition of surrounding materials.

AHRI-8007: Material Compatibility & Lubricants Research for Low-GWP Refrigerants.
The final report was previously available for AHRI members only, and now can be accessed by the public at the AHRI website. The project was completed in two parts: 1) chemical compatibility (evaluation of the impact of materials on the chemical stability of the refrigerants); and 2) material compatibility (evaluation of the impact of refrigerants on material properties).

The AHRTI co-sponsored ASHRAE 1665-RP, R-40 Stability with HVACR System Materials was recently published by ASHRAE. This project looks to determine the stability of R-40 (monochloromethane) with HVACR system materials, so that all industries who use refrigerants can determine the reliability and safety impacts that R-40 has on equipment. R-40 has recently been determined as the primary contaminant in mobile R-134a HVACR systems and, to a more limited extent, reported in R-22 and R-410A systems as well. The final report can be accessed either through the ASHRAE website, or through AHRI upon request.

AHRI Announces Two New Research Projects

AHRI launched two research projects in 2015. The contracts will be awarded this month.

AHRI-8017: Study on Ignition Sources Energy. The objective of the project is to evaluate energy produced by potential ignition sources in residential and commercial applications relative to minimum ignition energy of a list of A2L refrigerants, and investigate the likelihood of the ignition sources igniting the refrigerants.

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 US. The result of the research will provide guidance on estimating refrigerant emissions during the end of life recycling process.

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 this June.

AHRI-8012: Developing Fan Power Terminal Unit Performance Data and Models Compatible with EnergyPlus. This project is to 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 January, 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 unnecessarily stressing the heat exchanger. It will also establish guidelines for set back and extended absences 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 this October.

AHRI-8015: Leak Rates Assessment for Air Conditioning and Refrigeration Equipment. This project will conduct survey type research to analyze the information on the actual leakages for refrigeration equipment. The outcome will be a useful input to the equipment Life Cycle Climate Performance (LCCP) analysis and risk assessment for systems using mildly flammable refrigerants. The project is completed by ICF Incorporated LLC. The final report is in the final approval stage.

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 this November.

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-1467: Balancing the Latent Heat Load between Display Cases & Store Comfort Cooling. This project seeks to provide a comprehensive assessment of energy savings potential in supermarkets by optimized design and operation of the combined HVACR systems. The project is completed, and the final deliverable is being prepared.

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.

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-ASHRAE1641, 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-ASHRAE1645, 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