STUDI EKSPERIMENTALPENUKAR KALOR PIPA GANDA HELICAL PADASISTEM REFRIGERASI JOULE-THOMSON

The Joule Thomson (J-T) refrigeration system currently is being developed for cryogenic application to substitute Linde Hampson (L-H) refrigeration system. The advantage of the J-T refrigeration system is lower operating pressure than the L-H refrigeration system. The J-T refrigeration system works in pressure about 20 bar, while the L-H refrigeration system in about 200 bar. To get the desire cryogenic temperature, in the J-T refrigeration system, usually is used mixed refrigerants, whereas in this investigation is only used one refrigerant, that is R-22. The one of the J-T refrigeration system performance parameters is heat exchanger effectiveness (Iµ). To know the effect of diameter size and gap coils to the heat exchanger effectiveness, heat transfer coefficient and J-T cycle performance, in this research a helical double pipe heat exchanger is used in three variation of coils size diameter and their gaps or pitches, those are : 0 mm, 5 mm and 8 mm of gaps and 18.5 cm, 22 cm and 27 cm of coils diameter size. The results are: the highest of effectiveness ( Iµ ) of heat exchanger is 88 % at the smallest coils diameter (18.5 cm) and 5 mm of coil gap, the highest overall heat transfer coefficient (U) is 431W/m2 K at the smallest coils diameter (18.5 cm) and 8 mm of coil gap. The highest COP actual and refrigeration efficiency are 3, 15 and 73,3 % both are at the widest coils diameter (27 cm) either in 5 mm and 8 mm of gaps respectively.