Please provide the correct answer and explanation. 1. In a reciprocating compressor, minimum work is required during Constant volume compression Reversible-adiabatic compression Isothermal compression Isenthalpic compression 2. The efficiency of a constant volume of a constant volume cycle depends upon Pressure ratio Compression ratio Cut-off ratio Temperature

Please provide the correct answer and explanation. 1. In a reciprocating compressor, minimum work is required during Constant volume compression Reversible-adiabatic compression Isothermal compression Isenthalpic compression 2. The efficiency of a constant volume of a constant volume cycle depends upon Pressure ratio Compression ratio Cut-off ratio Temperature

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 12RQ: Refrigerators currently being manufactured in the United States are using______as their refrigerant.

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Air within a piston-cylinder assembly executes a Carnot heat pump cycle, as shown in the figure below. For the cycle, TH = 400 K and Tc = 300 K. The energy rejected by heat transfer at 400 K has a magnitude of 625 kJ per kg of air. The pressure at the start of the isothermal expansion is 325 kPa. TH Te p-v diagram for a Carnot gas refrigeration or heat pump cycle. Assuming the ideal gas model for the air, determine: (a) the magnitude of the net work input, in kJ per kg of air, and (b) the pressure at the end of the isothermal expansion, in kPa.
A refrigeration system operated on an ideal vapor-compression using R-12 with a vaporizing temperature of -10 degrees Celsius and a condensing temperature of 30 degrees Celsius, it requires 15 hp to drive the motor of the compressor. Find the ff: Enthalpies at each point of the cycle in kJ/kg Refrigerating Capacity in TOR • Mass of the Refrigerant in kg/s Percent Quality in the mixture Heat Rejected in kW Coefficient of Performance • Schematic and P-h Diagram
As shown below, a refrigeration cycle condenses a flow of ammonia from a saturated vapor at 4 barto a saturated liquid. The entering volumetric flow rate of the ammonia is 0.1 m3/s. The ammonia functions asthe cold reservoir for the refrigeration cycle, and the hot reservoir is at 25 ∘C. A faded specification sheet for therefrigeration cycle reads that the required power input is 35 kW.(a) Is this cycle possible? Why or why not?(b) If the cycle is impossible, how much work input is required to make the cycle
An ideal gas within a piston-cylinder assembly undergoes a Carnot refrigeration cycle, as shown in the figure below. The isothermal compression occurs at 325 K from 2 bar to 8 bar. The isothermal expansion occurs at 275 K. Determine: TH p-v diagram for a Carnot gas refrigeration or heat pump cycle. (a) the coefficient of performance, (b) the heat transfer to the gas during the isothermal expansion, in kJ per kmol of gas, (c) the magnitude of the net work input, in kJ per kmol of gas.
A R-134a home refrigerator operates on a simple cycle at pressures 1.8 bar-abs and 7.5 bar-abs. The refrigerant mass flow-rate is 0.005 kg/s. Fill up Tables 3a and 36. Part 3. Calculation: Performance of a Simple Refrigeration Cycle. Table Ja. Selected Thermodynamic properties of R-134a refrigerant according to the given cycle. kJ/ kg a Specific Enthalpy at suction A Specific volume at suction m/ kg kJ /g-K e Specific entropy at suction d Specific enthalpy at discharge Specific enthalpy after expansion hs4 31 kJ/ kg kJ / kg Table 3b. Performance of the home refrigerator according to its cycle of operation. kWatt a. Evaporator cooling capacity b Condenser heat rejection rate Q Cond kWatt Power required by compressor W Comp C. kWatt d Volume displacement of compressor e. Coefficient of Performance-Ref VCamp Li/s COP Ref f Coefficient of Performance-Canot COP RC & Flash-gas formed after expansion X4 kg / kg %3D
Question 6 of 14 -/2 > Referring to the reversible heat pump cycle shown in the figure, p1 = 14.7 Ib/in?, p4 = 41.5 lb/in?, v1 = 12.6 ft³/lb, v4 = 6.0 ft³/lb, and the gas is air obeying the ideal gas model. PI P4 pi V4 Determine TH, in °R, and the coefficient of performance. II
Derive the formula of efficiency of the following: a. Otto Cycle in terms of compression ratio r and specific heat ratio k
2.1 An air refrigeration cycle has pressure ratio of 8, temperature of air at beginning of compression is – 30°C and air is cooled up to 27°C after compression. Compression and expansion processes have isentropic efficiency of 85% and 90% respectively. Determine 2.1.1 the refrigeration capacity and 2.1.2 coefficient of performance. Consider Cp = 1.005 kJ/kg ·K, y = 1.4 and air flow rate of 1 kg/s.
SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C dut 246.36 kJ/kg OF P 0.8 MPa h2 = 286.69 kJ/kg P 0.72 MPa T= 26 C h3 = 87.83 kJ/kg h3 = h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS SAMARRA RING
SUBJECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS Example 2:- Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 MPa and -10°C at a rate of 0.05 kg/s and leaves at 0.8 MPa and 50°C. The refrigerant is cooled in the condenser to 26°C and 0.72 MPa and is throttled to 0.15 MPa. Disregarding any heat trans fer and pressure drops in the connecting lines between the components; determine (a) the rate of heat removal from the refrigerated space and the power input to the compressor, and (b) the coefficient of performance of the refrigerator. Solution: - P 0.14 MPa T=-10 C 212 h 246.36 kJ/kg da OF SAMARRA P 0.8 MPa VER h2 = 286.69 kJ/kg O P 0.72 MPa T= 26 C hg = 87.83 kJ/kg h3 =h = 87.83 KJ/kg h4 = h3 (throttling) h4 87.83 kJ/kg 0.8 MPa 50°C 0.72 MPa/ 26 C 0.15 MPa 0.14 MPa -10°C SUBIECT: THERMODYNAMIC COURSE: II ASSI.LACTURE: NATIQ ABBAS RING
you design a custom refrigeration system using 1,1,2-tetrafluoroethane (R-134a) as refrigerant.You design your ideal compression-based refrigeration cycle to operate between 2 bar and 9 bar. Before enteringthe ideal butterfly valve (delta H = 0), the refrigerant is a saturated liquid. Before entering the compressor, therefrigerant is saturated vapor. In fact, in isentropic operation, the refrigerant which leaves the compressor is alsosaturated vapor. The operation of the compressor and the evaporator is isobaric. Assuming a mass flow rate of1.5 kg / s, determine the compressor efficiency required to achieve a coefficient of performance of 6.96. Whatis ?? ̇ et ?? ̇ to this performance.
a refrigeration plant working on Bell Coleman cycle, air is compressed to 6 bar from 1 bar Its initial temperature is 300 K After compression, the air is cooled up to 350 K in a cooler before expanding back to a pressure of 1 bar Determine the theoretical COP of the plant and net refrigerating effect Take cp, = 1.005 kJ/kg K and cv = 0.718 kJ/kg K