DETERMINATION OF THERMAL-PROPERTIES OF DILUTE LIBR-WATER SOLUTIONS

We are developing an absorption air cooling system which can supply 2 degrees C chilled water for air cooling by the usage of dilute solutio ns of LiBr in water with an evaporating temperature of -6 degrees C as a nonfreezing refrigerant. However, there are few published data for the thermal properties of dilute LiBr-water solutions (0 to 30%) below 10 degrees C. In this paper, the freezing temperature and the saturat ed vapor pressure are reported. The results clearly show the possibili ty of developing a new type of LiBr absorption refrigerating machine t o generate evaporating temperatures below 0 degrees C. To obtain accur ate data for the design of this new type of absorption refrigerating m achine, an apparatus has been developed to measure the thermal propert ies of dilute LiBr-water solutions below 10 degrees C. The experimenta l arrangement consists of a cooling bath (340 x 240 x 190 mm) filled w ith fluorocarbon, a glass measuring bottle (phi 120 x 100 mm), and an absolute pressure gauge (0-1.3 kPa). The accuracy of the temperature, pressure, and density are within +/- 0.1 degrees C, 0.01 kPa,and +/- 0 .005 %, respectively.