Tomihisa Oouchi

Determination of thermal properties of dilute LiBr-water solutions

We are developing an absorption air cooling system which can supply 2°C chilled water for air cooling by the usage of dilute solutions of LiBr in water with an evaporating temperature of −6°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°C. In this paper, the freezing temperature and the saturated vapor pressure are reported. The results clearly show the possibility of developing a new type of LiBr absorption refrigerating machine to generate evaporating temperatures below 0°C. To obtain accurate data for the design of this new type of absorption refrigerating machine, an apparatus has been developed to measure the thermal properties of dilute LiBr water solutions below 10°C. The experimental arrangement consists of a cooling bath (340×240×190 mm) filled with fluorocarbon, a glass measuring bottle (ϕ120×100 mm), and an absolute pressure gauge (0–1.3 kPa). The accuracy of the temperature, pressure, and density are within ±0.1°C, 0.01 kPa, and ±0.005%, respectively.