- Author
- Walker, D. | Joback, K.
- Title
- Oil Additives for Drop-In Replacement Refrigerants. Phase 1. Final Report. April 8, 1994-October 8, 1994.
- Coporate
- Foster-Miller, Inc., Waltham, MA Molecular Knowledge Systems, Inc., Nashua, NH
- Sponsor
- Phillips Laboratory, Kirtland AFB, NM
- Report
- Phase 1; Final Report; PL-TR-95-1026, April 1995, 60 p.
- Distribution
- Available from Defense Technical Information Center LIMITED DISTRIBUTION to authorized U.S. Government agencies
- Contract
- F29601-94-C-0080
- Keywords
- refrigerants | oil additives | refrigeration | experiments | lubricant additives
- Identifiers
- compressor oil; miscibility; mineral oil
- Abstract
- HFC refrigerants are the leading candidates to replace CFCs in many cooling, air conditioning, and refrigeration applications because they have no ozne depleting potential and very low global warming potential. HFC refrigerants are not used as "drop-in" replacements because of the immiscibility of HFCs with the existing compressor lubricant. Synthetic oils have been developed for use with HFC refrigerants. To use these oils, however, the refrigeration system must be flushed of the original compressor lubricant. This flushing process is a major expense and makes conversion of existing systems economically unattractive. Phase 1 of this project addressed this problem by identifying additives that could be placed in the existing compressor lubricant to improve its miscibility with HFC refrigerants. These additives were initially identified through the use of solubility parameter theory. Testing was then conducted to measure the miscibility of HFC refrigerants and mineral oil with additives present. The solubility of R-404a (the HFC substitute for R-502) in mineral oil was raised from less than 6 percent to 17.3 percent at OºC through the use of an additive. This value is close to the solubility of R-502 in mineral oil at this same temperature (20 percent). Future efforts will first optimize the additive so that other desired properties such as low volatility and good chemical and thermal stability can be achieved. The impact of the additive on the lubrication properties of the oil will also be investigated. A screening will be conducted to eliminate any toxicity or safety risks. Test compressor calorimeters will also be constructed and a full set of performance and wear tests will be performed.