Question

NOTE: This is a multi-part question Once an answer is submitted you will be unable to return to this part Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.4 MPa and 140 kPa with refrigerant-134a as the working fluid. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where the pressure in the upper and lower cycles are 0.7 and 08 MPa, respectively. In both cycles, the refrigerant is a saturated liquid at the condenser exit and a saturated vapor at the compressor inlet, and the isentropic efficiency of the compressor is 80 percent. The mass flow rate of the refrigerant through the lower cycle is 0.28 kg/s Take the required values from saturated refrigerant-134a tables.) Determine the mass flow rate of the refrigerant through the upper cycle. (You must provide an answer before moving to the neixt part) The mass flow rate of the refrigerant through the upper cycle is D- ]kgs Determine the rate of heat removal from the refrigerated space. mou must provide an answer before moving rate of heat removal from the refrigerated space is匚-161 kw. Determine the COP of the refrigerator The COP of the refrigerator is

Answer 1

4-MPa valve hent 10 SMP Condonsi 2 Ex alMe I4-0kPa ㄣ h-hg @ i 40 kPa Ξ 239 r 16 kJlks hr -h h2-2346

0.3867 (28a-t-265.03) +0.28(285.77-23%) - 19 77 k w 40, 2.33 19.77 2-03