IMPROVED WORKING FLUIDS FOR ABSORPTION CYCLES

THE DEVELOPMENT OF MORE COMPETITIVE ABSORPTION REFRIGERATIONSYSTEMS COULD REDUCE PRIMARY ENERGY USE AND ENERGY COSTS ANDALLOW USE OF NATURAL GAS FOR COOLING. ABSORPTION CYCLE EFFICIENCY APPROACHES THEORETICAL CYCLE LIMITS, BUT THE FLUIDS USED LIMIT THE RANGE OF OPERATING TEMPERATURES AND PRESSURES. PROBLEMS WITH CONVENTIONAL LITHIUM BROMIDE (LIBR)-WATER AND WATER-AMMONIA SYSTEMS ALSO INCLUDE CORROSIVITY AND TOXICITY, CRYSTALIZATION, AND FLUID VOLATILITY. MIXTURES OF GLYCOLS AND POLYMERS AS THE ADSORBENT, WITH EITHER WATER OR METHANOL AS THE REFRIGERANT,WILL BE TESTED AS ABSORPTION CYCLE FLUIDS. USED ALONE, THE LOW WATER CAPACITIES OF PURE GLYCOLS AT LOW WATER PRESSURES RESULT IN UNACCEPTABLY LOW ABSORPTION CYCLE COEFFICIENTS OF PERFORMANCE (COPS). HOWEVER, IT HAS BEEN SHOWN THAT ADDING CERTAIN POLYMERS TO GLYCOLS RESULTS IN A THREEFOLD CAPACITY IMPROVEMENT AT LOW WATER VAPOR PRESSURES. GLYCOL-POLYMER-WATER SYSTEMS HAVE THE POTENTIAL FOR COOLING COPS SIMILAR TO LIBR-WATER AND FOR OPERATING OVER A WIDER RANGE OF CONDITIONS WITHOUT CRYSTALLIZATION. THEY ARE ALSO NON-CORROSIVE. GLYCOL-POLYMER-METHANOL SYSTEMS COULD BE USED FOR BOTH HEAT PUMP AND COOLING APPLICATIONS, WOULD HAVE LOWER DISTILLATION ENERGY REQUIREMENTS AND HIGHER COPS, AND WOULD BE LESS TOXIC THAN WATER-AMMONIA. THERMODYNAMIC RELATIONSHIPS OF THE GLYCOL-POLYMER SYSTEM WITH WATER AND METHANOL REFRIGERANTS WILL BE DETERMINED DURING PHASE I USING A SARTORIUS MICROBALANCE. THE DATA WILL BE USED TO DESIGN IMPROVED ABSORPTION CYCLES.