21CR Program
The HVAC&R Research for the 21st Century (21CR) program (1999 - 2005) was a multiyear research collaborative research program administered by the Air-Conditioning and Refrigeration Technology Institute (ARTI), now known as (AHRTI).

The overall emphasis of the 21CR program was to undertake research that would enable HVAC&R manufacturers to offer equipment and services in the next decade that, once integrated into building and process applications, would utilize dramatically less energy (as compared to today's applications) while addressing the comfort and indoor environmental quality (IEQ) needs of building occupants. Some of these energy and IEQ improvements will accrue by innovative advancements in the heating, ventilation, air-conditioning and refrigeration (HVAC&R) equipment itself. Other benefits will be garnered by better incorporation of improved equipment into more comprehensive systems for particular applications such as buildings or refrigeration processes.

21CR Focus Areas
The effort fostered an environment where technical barriers were identified, solutions investigated, and information shared. Areas of interest were related to all aspects of the HVAC&R industry. Focus areas were:

• alternative equipment
• high efficiency equipment
• smart building system integration
• improved indoor environmental quality
• environmentally-friendly working fluids

The 21CR program was funded, in part, by U.S. Department of Energy Cooperative Agreement DE-FC05-99OR22674 with co-funding from AHRI, the Copper Development Association, the Heating, Refrigeration and Air-Conditioning Institute of Canada, the Refrigeration Service Engineers Society, the California Energy Commission and the New York State Energy Research and Development Authority.

21CR Program Technical Results
Electronic copies of 21CR project reports are available upon request from AHRI Director of Research.


MCLR Program
The Materials Compatibility and Lubricant Research (MCLR) program (1991-2001) was a multi-year research grant administered by the Air-Conditioning and Refrigeration Technology Institute (ARTI) now known as AHRTI. The MCLR program supported critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addressed refrigerant and lubricant properties, materials compatibility, system related issues, and test methods development. The work was guided by the MCLR Advisory Committee which consisted of technical experts from the refrigeration and air-conditioning industry and government agencies.

The MCLR program conducted extensive research on the properties and materials compatibility of HCFC-123, HCFC-124, HCFC-142b, HFC-32, HFC-125, HFC-134a, HFC- 143a, HFC-152a and HFC-245ca with a number of lubricants. Although HCFC refrigerants with alkylbenzene and polyglycol lubricants were included in the initial screening tests, most of the work was centered on HFC refrigerants with polyolester (POE) lubricants. Baseline comparative measurements were also conducted with CFC-11, CFC-12 and HCFC-22 with mineral oil. Properties examined included thermophysical and transport properties and infrared spectra of refrigerants; miscibility, viscosity, and foaming characteristics of refrigerant-lubricant mixtures. Compatibility of refrigerant-lubricant mixtures were tested with metals, motor insulating materials, elastomers, plastics, desiccants, process fluids, and lubricant additives. System related issues studied included lubricant circulation, fractionation of blends, effects of system contaminants, products of motor burn-outs, flushing and clean-out methods, the effectiveness of desiccant driers, and limited heat transfer enhancement technologies. Methods development research focused on the development of an accelerated method for screening the compatibility of motor insulating materials with new refrigerant-lubricant mixtures and research to improve methods for testing the flammability of refrigerants and refrigerant blends.

This program was supported, in part, by U.S. Department of Energy grant number DE-FG02-91CE23810. Federal funding supporting this program constituted 93.36% of allowable costs. Funding from non-government sources supporting this program consisted of direct cost sharing totaling 6.64% of allowable costs, and significant in-kind contributions from the air- conditioning and refrigeration industry.

21CR Program Technical Results
All reports have since been consolidated in electronic format on CD-ROM and are available upon request from the AHRI Director of Research.