(Solved): a) A reciprocating air compressor has cylinder with 30cm bore and 40cm stroke. Compressor ad ...

a) A reciprocating air compressor has cylinder with $30\mathrm{cm}$ bore and $40\mathrm{cm}$ stroke. Compressor admits air at 1 bar, $20^{\circ }\mathrm{C}$ and compresses it up to 5 bar. Compressor runs at $150\mathrm{rpm}$. Considering the compressor to be single acting, single stage and has polytropic index of 1.2. Considering the compression process to be isothermal, polytropic and adiabatic, determine the following: [4] a. Draw the P-V diagram for these processes b. Find out the mean effective pressure and horsepower required to run the compressor c. Calculate the isothermal efficiencies when the compression is of polytropic and adiabatic type b) A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerant space at $-30^{\circ }\mathrm{C}$ by rejecting its waste heat to cooling water that enters the condenser at $15^{\circ }\mathrm{C}$ at a rate of $0.25\mathrm{kg}/\mathrm{s}$ and leaves at $25^{\circ }\mathrm{C}$ The refrigerant enters the condenser at $1.2\mathrm{MPa}$ and $60^{\circ }\mathrm{C}$. The inlet state of the compressor is $60\mathrm{kPa}$. Determine the following: [4] a. Quality of refrigerant at evaporator inlet b. Refrigeration load c. COP of the refrigerator