Problem 1 (Using thermodynamic tables) A large refrigeration plant is to be maintained at -12 C. It requires refrigeration at a rate of 120 kW. The condenser of the plant is to be cooled by liquid water, which experiences a temperature rise of 10 C as it flows over the coils of the condenser. Assuming the plant operates on the ideal vapor-compression cycle using refrigerant- 134a between the pressure limits of 100 and 700 kPa, determine (a) the mass flow rate of the refrigerant, (b) the power input to the compressor, and (c) the mass flow rate of the cooling water

Problem 1 (Using thermodynamic tables) A large refrigeration plant is to be maintained at -12 C. It requires refrigeration at a rate of 120 kW. The condenser of the plant is to be cooled by liquid water, which experiences a temperature rise of 10 C as it flows over the coils of the condenser. Assuming the plant operates on the ideal vapor-compression cycle using refrigerant- 134a between the pressure limits of 100 and 700 kPa, determine (a) the mass flow rate of the refrigerant, (b) the power input to the compressor, and (c) the mass flow rate of the cooling water

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

Chapter22: Condensers

Section: Chapter Questions

Problem 7RQ: When a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be...

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Similar questions

Why is two-stage compression popular for extra-low-temperature refrigeration systems?
When a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be higher in temperature than the entering air temperature.
Condensers in these refrigerators are all_______cooled.
Refrigerators currently being manufactured in the United States are using______as their refrigerant.
3. Asteady-flow Carnot refrigeration cycle uses refrigerant-134a as the working fluid. The refrigerant changes from saturated vapor to saturated liquid at 30°C in the condenser as it rejects heat. The evaporator pressure is 160 kPa. Determine a-the coefficient of performance b-the amount of heat absorbed from the refrigerated space c-the net work input
A refrigerator operates on the ideal vapor-compression refrigeration cycle and uses refrigerant-134a as the working fluid. The condenser operates at 300 psia and the evaporator at 20°F. If an adiabatic, reversible expansion device were available and used to expand the liquid leaving the condenser, how much would the COP improve by using this device instead of the throttle device? The COP improves by % by using the adiabatic, reversible expansion device instead of the throttle device.
question 51 An ideal vapor-compression refrigeration cycle that uses refrigerant-134a as its working fluid maintains a condenser at 800 kPa and the evaporator at -12 C. Determine this system’s COP and the amount of power required to service a 150 kW cooling load. What is the mass flow rate of refrigerant in kg/s to 4 decimal places? No need to add units to the answer.
2. A simple vapor compression cycle uses 2.43 kg/min of ammonia refrigerant for the system. The operating conditions are 25°C and -20°C (condenser and evaporator temperatures, respectively). Determine the ff: • Enthalpy at each point of the cycle Refrigerating Effect • Compressor Work Energy Rejected • Refrigerating capacity in TOR Compressor Power • Heat Rejected . Coefficient of Performance • Draw the P-h Diagram with labels Note: Draw the P-h Diagram with labels. Show your system balancing for checking.
a) A freezer working on an ideal vapour-compression refrigeration cycle uses refrigerant R- 134a with a mass flow rate of 0.10 kg/s. The refrigerant leaves the evaporator as saturated vapour at a temperature of -8 °C. It leaves the condenser as saturated liquid at a pressure of 0.8 MPa. Determine the power required to drive the compressor. Note that the thermodynamic properties of R-134a are attached at the end of the paper. 0.8 MPa A Figure Q4 b) A freezer wall is made of a composite material with a thickness of 20 mm and a conductivity of 0.03 W/m-K. Air temperatures inside and outside the freezer are -6 °C and 20 °C, respectively. The convection coefficient is 2 W/m² K on both the inner and outer surfaces of the freezer wall. Determine the heat flux through the freezer wall. -8 C
. A steady-flow Carnot refrigeration cycle uses refrigerant-134a as the working fluid. The refrigerant changes from saturated vapor to saturated liquid at 608C in the condenser as it rejects heat. The evaporator pressure is 140 kPa. Show the cycle on a T-s diagram relative to saturation lines, and determine (a) the coefficient of performance, (b) the amount of heat absorbed from the refrigerated space, and (c) the net work input.
2. Consider a two-stage compression refrigeration system operating between the pressure limits of 0.8 and 0.14 MPa. The working fluid is refrigerant-134a. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.32 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. Assuming the refrigerant leaves the evaporator as a saturated vapor and both compressors are isentropic, determine (a) the fraction of the refrigerant that evaporates as it is throttled to the flash chamber, (b) the amount of heat removed from the refrigerated space and the compressor work per unit mass of refrigerant flowing through the condenser,…
NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A refrigerator uses refrigerant-134a as the working fluid and operates on the vapor-compression refrigeration cycle. The evaporator and condenser pressures are 100 kPa and 1400 kPa, respectively. The isentropic efficiency of the compressor is 88 percent. The refrigerant enters the compressor at a rate of 0.022 kg/s superheated by 26.37°C and leaves the condenser subcooled by 4.4°C. Problem 11.021.a - Actual refrigeration cycle Determine the rate of heat removal from the refrigerated space, the rate of heat rejection from the refrigerant to the environment, the power input, and the COP. (Take the required values from saturated refrigerant-134a tables.) The rate of heat removal from the refrigerated space is kW. The rate of heat rejection from the refrigerant to the environment is kW. The power input is kW. The COP is .