| Title |
A Study on the Determination of Mixed Refrigerant for the Joule-Thomson Cryocooler |
| Keywords |
Joule-Thomson cooler ; J-T 냉동기 ; Mixed refrigerant ; 혼합 냉매 ; Component ; 구성 성분 ; Composition ; 조성비 ; Dew point ; 이슬점 ; Normal boiling point ; 끓는점 |
| Abstract |
The conceptual determination of mixed-refrigerant (MR) for a closed Joule- Thomson cryocooler is described in this paper. The thermodynamic cycle design was mainly considered to develop a cryocooler by using a compressor of domestic air-conditioning unit. The target cooling performance of the designed cryocooler is 10 W around 70 K with less than 5 kJ/kg enthalpy rise. The systematic approach of choosing a proper refrigerant among 20 different kinds of mixture for such cryogenic temperature was introduced in detail. The main components of the cryocooler are compressor, evaporator, oil separator, after-cooler, counterflow heat exchanger, and J-T expansion device. Due to the limitation of the compressor operation range, the temperature after the compression was limited below 117℃ (390 K) and the temperature before compression was restricted above 5℃(278 K). 20 atm of discharging pressure(high pressure) and less than 3 atm suction pressure (low pressure) were the design conditions. The inlet temperature of a counterflow heat exchanger in the high pressure side was about 300 K. The proper composition of the mixed refrigerant for the designed J-T cryocooler is 15% mol of N2, 30% mol of CH4, 30% mol of C2H6, 10% mol of C3H8 and 15% mol of i-C4H10. |