AN EXPERIMENTAL STUDY TO SHOW THE EFFECT OF DIFFERENCE IN CAPILLARY TUBE LENGTH ON COMPRESSION REFRIGERATION SYSTEM PERFORMANCE BY USING THE REFRIGERANT (R134A)

Abstract

An experimental compression refrigeration system performance study was presented in this research depending on the change of the capillary tube length and by using (R134a).The tests were done for three capillary tube lengths (80,100,120cm) and changing mass flow rate for each length. Their values were (2 – 6g/s) with capillary tube diameter (2mm). The results showed that the (COP) decreases by (38.14%) as the mass flow rate increases from (2 – 6g/s), and by (6.65%) as the capillary tube length increases from (80-120 cm). At (L=80Cm) the (COP) value will be greater than it's value at (L=120Cm) for lowest mass flow rate, while it's values converge for all lengths at high mass flow rate .Also it was declared that (COP) will decrease as the condenser temperature increases for all lengths.The study showed that the compressor compression power increases as the condenser temperature increases by (68.36%), and increases as the capillary tube length increases by (9.54%) with convergence value at (100 cm) and (120 cm) . This study showed also that sub-cooling temperature stays constant at low flow rates, and decreases at higher flow rates by (34.35%).Through this study was found best length used in refrigeration cycle at lowest mass flow rate (2.78 g/s) is (80Cm) which will give highest performance and lowest compression power, and at high mass flow rate (5.83 g/s) found the length (100Cm) will give highest performance and lowest compression power.