Question

In: Mechanical Engineering

A 30 kW ammonia compressor (ˠ = 1.2) operates with an evaporator and condenser temperatures of...

A 30 kW ammonia compressor (ˠ = 1.2) operates with an evaporator and condenser temperatures of 10 C & 40 C, respectively. The clearance factor is 5% with compression or adiabatic efficiency 85%, mechanical efficiency 80% & actual volumetric efficiency 75%.
Determine:
a. Draw the PH diagram indicating all enthalpy & sp. vol.
b. Clearance volumetric efficiency
c. Actual work, kJ/kg
d. Ideal COP
e. Actual COP
f. Mass of refrigerant flow, kg/s
g. Indicated work, kW
h. Brake work, kW

Expert Solution

Answer(a) ph diagram is given below

Enthalpy point

h1= 1451.78K j/kg

h2= 1584.66K j/kg

h3= h4= 371.35K j/kg

Specific volume

v1= 0.2054 m^3/kg

v2= 0.1152 m^3/kg

v3= 1.7256*10^(-3) m^3/kg

v4= 0.02565 m^3/kg

Answer(b)- volumetric efficiency= 94.17%

Answer(c)- actual work= 93.798K j/kg

Answer(d)- ideal cop= 8.13

Answer(e)- actual cop= 11.52

Answer(f)- mass of refrigerant flow= 0.32 kg/sec

Answer(g)- indicated work(in watt)= 37.52K watt

Answer(h)- brake work(in watt)= 30.016K watt

Details solutions is given below

samet mamat answered 6 days ago

A 100 kW, 8-cylinder R-22 compressor with 20 kW power operates at zero & 40 C...

A 100 kW, 8-cylinder R-22 compressor with 20 kW power operates at zero & 40 C evaporating & condensing temps. The compressor bore 0.07 m & stroke 0.06 m with clearance volume of 5% runs at 30 rev/sec. Determine: a. Draw the PH diagram indicating all enthalpy & sp. vol. b. Volumetric efficiency c. Suction volume, m3/s d. Piston displacement, m3/s e. Actual volumetric efficiency f. Actual work of compressor, kJ/kg g. Isentropic work of compression, kJ/kg h. Compression or...

Assume that the difference in temperature between a condenser and a evaporator decreases. How will the...

Assume that the difference in temperature between a condenser and a evaporator decreases. How will the volumetric efficiency of the cooling compressor be affected by this. Show this by describing it in a pv diagram.

In a household refrigerator with evaporator temperature -10 ° C and condenser pressure 1000 kPa R134a...

In a household refrigerator with evaporator temperature -10 ° C and condenser pressure 1000 kPa R134a is used as refrigerant. Saturated steam at the compressor inlet The refrigerant that is in the state is in the state of saturated liquid at the outlet of the condenser. Entropy at the compressor outlet is 0.985 kJ / kgK. According to this, a) Cycle T-s and P-h diagrams, showing saturation curves on the diagram Draw. b) Calculate the isentropic efficiency of the compressor....

Water enters the condenser of surface type; the temperatures of the water that is used to...

Water enters the condenser of surface type; the temperatures of the water that is used to cool the steam is 17oC and 28oC respectively. The pressure of the condenser is at 0.055 bar and 0.87 dry fraction. The overall heat transfer coefficient in the condenser is 3 kW/m2.oC. The condenser has three passes and tubes used have 17.6 mm internal diameter and 20 mm external diameter. If the flow area is 1.3 m2, Design the condenser. If the condenser is...

The isentropic efficiency of an ammonia, NH3, refrigeration plant is 0.88. The ammonia enters the compressor...

The isentropic efficiency of an ammonia, NH3, refrigeration plant is 0.88. The ammonia enters the compressor as dry saturated vapour at -16 ? and leaves the compressor in a superheated state at 11.67 bar. The refrigerant is then condensed and undercooled by 4K at constant pressure before being expanded at -16 ?. (NEED TO USE STEAM TABLES FOR NH3, PLEASE ONLY ANSWER IF YOU HAVE A GOOD UNDERSTANDING OF REFRIGERTION) a)Draw a schematic of the plant and the cycle on...

Rankine cycle operates on boiler pressure 15 MPa and condenser pressure of 30 kPa. Superheated steam...

Rankine cycle operates on boiler pressure 15 MPa and condenser pressure of 30 kPa. Superheated steam enters the high-pressure turbine at 450°C. The high-pressure turbine expands the steam and enters the re-heater at 2.5 MPa. The steam is reheated until temperature reaches 450°C before being expanded in low-pressure turbine to condenser pressure of 30 kPa. Assume the isentropic efficiency of the low-pressure and high-pressure turbines are 94% and 89% respectively, and pump is working isentropically. Neglect the change in kinetic...

A compressor is to run at 250 rpm and requires 75 kW. The drive is provided...

A compressor is to run at 250 rpm and requires 75 kW. The drive is provided by V-belts from an electric motor running at 750 rpm. The pitch diameter of the pulley on the compressor is 750 mm and the centre distance between the motor shaft and compressor shaft is 1500 mm. Determine the number of V-belts required to transmit this power if each belt has a cross-sectional area of 375 mm2, density of 1000 kg/m3 and an allowable stress...

Why do we measure temperatures at the evaporator rather than the suction pressure?

Draw water and ammonia cycle in Einstein refrigerator, from to condenser + generator, mark and name...

Draw water and ammonia cycle in Einstein refrigerator, from to condenser + generator, mark and name each component

You are looking to purchase the DeWalt air compressor. Assuming the compressor operates (outputs) air at...

You are looking to purchase the DeWalt air compressor. Assuming the compressor operates (outputs) air at 90psi and at 110F. If the atmospheric pressure is 0 psig and the atmospheric temperature is 65F, how much free air will the compressor consume in cubic feet (ft3 )/Minute to handle the 5 standard cubic feet per minute (SCFM)? • DeWalt Specifications -- 1.6 HP electric engine gets the job done. High-pressure motor with consistent draw requirements can be run with a 12-Gauge...