1. Liquid refrigerant leaves the condenser of an ammonia vapor compression system under a pressure of 153 psia and at a temperature of 70 F, evaporating pressure 23.74 psia and the vapor leaves the evaporator at 5 F. Otherwise, the system follows the theoretical single-stage cycle. Find (a) the enthalpy of the liquid entering the expansion valve, the (b) refrigerating effect in Btu per lb, and (c) the coefficient of performance.

1. Liquid refrigerant leaves the condenser of an ammonia vapor compression system under a pressure of 153 psia and at a temperature of 70 F, evaporating pressure 23.74 psia and the vapor leaves the evaporator at 5 F. Otherwise, the system follows the theoretical single-stage cycle. Find (a) the enthalpy of the liquid entering the expansion valve, the (b) refrigerating effect in Btu per lb, and (c) the coefficient of performance.

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 2RQ: The operating condition for the single compressor in a household refrigerator is the lowest box...

See similar textbooks

Similar questions

Why is two-stage compression popular for extra-low-temperature refrigeration systems?
Refrigerators currently being manufactured in the United States are using______as their refrigerant.
Welded ______sealed compressors are normally used in household refrigerators.
The operating condition for the single compressor in a household refrigerator is the lowest box temperature, which is typically A. 0F B. -20F C. 20F D. 40F
Steam is supplied to a two-stage turbine at 48 bar and 400 °C. It expands in the firstturbine until it is just dry saturated, then it is re-heated to 400 °C and expandedthroughthe second-stage turbine. The condenser pressure is 0.04 bar. Determine the specific work output of the system to 3 d.p? what is the specific entalphy in kJ/kg for state 2?
A two-stage refrigeration system operates with ammonia refrigerant flowing at the rate of 15 kg/min through the evaporator. The saturation temperature in the condenser and evaporator units have been noted to be 40⁰C and - 15⁰C respectively. If the system has intercooling by liquid refrigerant at 4.25 bar, determine (a) The capacity and COP of the system. (b) How will these parameters be affected if the compression is carried out in a single stage unit ; the operating temperature limits remaining the same? Use the p-h chart and property tables for saturated ammonia refrigerant
2. A vacuum refrigeration system consists of a large insulated flash chamber kept at low pressure by steam ejector which pumps vapor to a condenser. Condensate is removed by condensate to an air vent. Warm return water enters the flash chamber at 13°C, chilled water comes out of the flash chamber at 5°C Vapor leaving the flash chamber has a quality of 0.97 and the temperature in the condenser is 320C. For 350 kw of refrigeration (a) How much chilled water at 5°C does this system provide? (b) How much make-up water is needed? (c) How much vapor must the steam ejector remove from the flash chamber?
In an ideal vapor-compression refrigeration cycle, the refrigerant enters the compressor as a saturated vapor and is cooled to the saturated liquid state in the condenser. It is then throttled to the evaporator pressure and vaporizes as it absorbs heat from the refrigerated space. Figure Q3.1 depicts the description of this process. Warm environment QH Condenser Expansion valve Compressor Evaporator Cold refrigerated space Figure Q3.1: Ideal vapor-compression refrigeration cycle. Assuming a refrigerator operates on this principle and uses refrigerant-134a as the working fluid, answer the following questions. (a) The condenser operates at 1.6 MPa and the evaporator at -6°C. If an adiabatic, reversible expansion device was available and used to expand the liquid leaving the condenser, (i) Calculate the COP improve by using this device instead of the throttle device. (ii)Illustrate a T-s diagram that represents the ideal vapor-compression refrigeration cycle described in (a)
In an ideal vapor-compression refrigeration cycle, the refrigerant enters the compressor as a saturated vapor and is cooled to the saturated liquid state in the condenser. It is then throttled to the evaporator pressure and vaporizes as it absorbs heat from the refrigerated space. Figure Q3.1 depicts the description of this process. Warm environment Condenser Win Expansion valve Compressor Evaporator Cold refrigerated space Figure Q3.1: Ideal vapor-compression refrigeration cycle. (b) The same working fluid enters the condenser that operates between 0.14 to 0.8 MPa, and flow rate of refrigerant is 0.05 kg/s, Evaluate the rate of heat removal from the refrigerated space and the power input to the compressor. (i) (ii) Analyze the rate of heat rejection to the environment. (iii) Determine the COP of the refrigerator for this process. (iv) Predict the power input if the throttling valve is replaced by an isentropic turbine. Justify on the difference on the power input measured between…
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
A heat pump cycle using water as the working fluid consists of a compressor, a condenser, an expansion valve, and an evaporator. Saturated vapor with mass flow rate of 1 kg/s at 0.5 MPa (state 1) enters the condenser and leaves it as saturated liquid at the same pressure (state 2). The pressure in the evaporator is 0.01 MPa. The condenser and the evaporator processes are isobaric. The compressor is adiabatic and reversible. The valve is adiabatic. A. List all the known information and assumptions. B. Determine the heat output of the condenser (QH) C. Determine the heat input of the evaporator(Qc) D. Determine the coefficient of performance of the heat pump. E. Determine the coefficient of performance of a Carnot heat pump running between the same temperatures TH and TC at the evaporator and condenser. F. Calculate the entropy generation in the compressor. G. Draw the TS diagram for the cycle on paper. (Hint: you must calculate T1, T2, T3, T4, h1, h2, h3, h4, s1, s2, s3, s4, and draw…
1.Refrigerator 1 simulates an ideal refrigerator and therefore operates on a Carnot cycle using R-134a as the refrigerant at a flow rate of 1.4 kg/sec. The condensing and evaporating temperatures are 30 °C and -10 °C, respectively. To assess the performance of Refrigerator 1, you must submit the report. of the project with the following information: a) Enthalpies corresponding to the states indicated in the cycle (1, 2, 3 and 4); b) The cooling rate (Q L ); c) The work supplied to the fluid by the compressor; d) The work generated by the turbine; e) The condenser heat rejection rate (Q H ); f) The coefficient of performance of the cycle. Important detail: For the energy balance, make the following considerations: ✓ Permanent regimen; ✓ Kinetic and potential energy variations are negligible; ✓ Compressor and turbine operate adiabatically; ✓ Evaporation and condensation steps are labor-free.