EBK THERMODYNAMICS: AN ENGINEERING APPR
8th Edition
ISBN: 8220100257056
Author: CENGEL
Publisher: YUZU
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Chapter 11.10, Problem 61P
A two-evaporator compression refrigeration system like that in Fig. P11–62 uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condenser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The refrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.
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A two-evaporatoor compression refrigeration system like that in the Figure below uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condeser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The regrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.
*
1. A cascade refrigeration
system using R - 22 in the low
- temperature circuit and
ammonia (R - 717) in the high
- temperature circuit has a
load of 150 kW. The low -
temperature circuit operates
at an evaporating
temperature of -50°C and a
condensing pressure of 500
kPa. Refrigerant leaves the
low temperature evaporator
as saturated vapor and enters
the suction of the low -
mperature compressor at -
45°C. Liquid refrigerant exits
the condenser at 02°C. The
high temperature circuit
operates at an evaporating
temperature of -10°C and a
condensing pressure of 1200
kPa. The refrigerant exits both
evaporator and condenser at
saturated conditions.
Calculate the power input to
the low-temperature circuit
compressor, kW.
A two-evaporator compression refrigeration system as shown in the figure uses refrigerant-134a as the working fluid. The system
operates evaporator 1 at 0°C, evaporator 2 at -26.4°C, and the condenser at 800 kPa. The refrigerant is circulated through the
compressor at a rate of 0.1 kg/s, and the low-temperature evaporator serves a cooling load of 8 kW. Determine the cooling rate of the
high-temperature evaporator, the power required by the compressor, and the COP of the system. The refrigerant is a saturated liquid
at the exit of the condenser and a saturated vapor at the exit of each evaporator, and the compressor is isentropic. The pressure
reducing valve drops the pressure of the evaporator 1 discharge to evaporator 2 discharge pressure.
(Take the required values from saturated refrigerant-134a tables.)
1
↑
7
Pressure
reducing
valve
m₁ + m₂
Condenser
m₁
Evaporator 1
Evaporator 2
m₂
S
The cooling rate of the high-temperature evaporator is
of the system is
3
kW, the power required by…
Chapter 11 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
Ch. 11.10 - Why is the reversed Carnot cycle executed within...Ch. 11.10 - Why do we study the reversed Carnot cycle even...Ch. 11.10 - 11–3 A steady-flow Carnot refrigeration cycle uses...Ch. 11.10 - Does the ideal vapor-compression refrigeration...Ch. 11.10 - Why is the throttling valve not replaced by an...Ch. 11.10 - It is proposed to use water instead of...Ch. 11.10 - In a refrigeration system, would you recommend...Ch. 11.10 - Does the area enclosed by the cycle on a T-s...Ch. 11.10 - Consider two vapor-compression refrigeration...Ch. 11.10 - The COP of vapor-compression refrigeration cycles...
Ch. 11.10 - An ice-making machine operates on the ideal...Ch. 11.10 - A 10-kW cooling load is to be served by operating...Ch. 11.10 - 11–13 An ideal vapor-compression refrigeration...Ch. 11.10 - 11–14 Consider a 300 kJ/min refrigeration system...Ch. 11.10 - 11–16 Repeat Prob. 11–14 assuming an isentropic...Ch. 11.10 - 11–17 Refrigerant-134a enters the compressor of a...Ch. 11.10 - A commercial refrigerator with refrigerant-134a as...Ch. 11.10 - 11–19 Refrigcrant-134a enters the compressor of a...Ch. 11.10 - A refrigerator uses refrigerant-134a as the...Ch. 11.10 - The manufacturer of an air conditioner claims a...Ch. 11.10 - Prob. 23PCh. 11.10 - How is the second-law efficiency of a refrigerator...Ch. 11.10 - Prob. 25PCh. 11.10 - Prob. 26PCh. 11.10 - Prob. 27PCh. 11.10 - 11–28 Bananas are to be cooled from 28°C to 12°C...Ch. 11.10 - A vapor-compression refrigeration system absorbs...Ch. 11.10 - A refrigerator operating on the vapor-compression...Ch. 11.10 - A room is kept at 5C by a vapor-compression...Ch. 11.10 - Prob. 32PCh. 11.10 - 11–33 A refrigeration system operates on the ideal...Ch. 11.10 - When selecting a refrigerant for a certain...Ch. 11.10 - Consider a refrigeration system using...Ch. 11.10 - A refrigerant-134a refrigerator is to maintain the...Ch. 11.10 - A refrigerator that operates on the ideal...Ch. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - Do you think a heat pump system will be more...Ch. 11.10 - What is a water-source heat pump? How does the COP...Ch. 11.10 - Prob. 42PCh. 11.10 - Refrigerant-134a enters the condenser of a...Ch. 11.10 - Prob. 45PCh. 11.10 - A heat pump using refrigerant-134a heats a house...Ch. 11.10 - How does the COP of a cascade refrigeration system...Ch. 11.10 - A certain application requires maintaining the...Ch. 11.10 - Consider a two-stage cascade refrigeration cycle...Ch. 11.10 - Can a vapor-compression refrigeration system with...Ch. 11.10 - Prob. 52PCh. 11.10 - Prob. 53PCh. 11.10 - Repeat Prob. 1156 for a flash chamber pressure of...Ch. 11.10 - Prob. 56PCh. 11.10 - Prob. 57PCh. 11.10 - 11–58 Consider a two-stage cascade refrigeration...Ch. 11.10 - Prob. 59PCh. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - Repeat Prob. 1163E if the 30 psia evaporator is to...Ch. 11.10 - How does the ideal gas refrigeration cycle differ...Ch. 11.10 - Devise a refrigeration cycle that works on the...Ch. 11.10 - How is the ideal gas refrigeration cycle modified...Ch. 11.10 - Prob. 66PCh. 11.10 - How do we achieve very low temperatures with gas...Ch. 11.10 - 11–68E Air enters the compressor of an ideal gas...Ch. 11.10 - Prob. 69PCh. 11.10 - Air enters the compressor of an ideal gas...Ch. 11.10 - Repeat Prob. 1173 for a compressor isentropic...Ch. 11.10 - Prob. 73PCh. 11.10 - Prob. 74PCh. 11.10 - Prob. 75PCh. 11.10 - A gas refrigeration system using air as the...Ch. 11.10 - An ideal gas refrigeration system with two stages...Ch. 11.10 - Prob. 78PCh. 11.10 - Prob. 79PCh. 11.10 - What are the advantages and disadvantages of...Ch. 11.10 - Prob. 81PCh. 11.10 - Prob. 82PCh. 11.10 - An absorption refrigeration system that receives...Ch. 11.10 - An absorption refrigeration system receives heat...Ch. 11.10 - Heat is supplied to an absorption refrigeration...Ch. 11.10 - Prob. 86PCh. 11.10 - Prob. 87PCh. 11.10 - Prob. 88PCh. 11.10 - Prob. 89PCh. 11.10 - Consider a circular copper wire formed by...Ch. 11.10 - An iron wire and a constantan wire are formed into...Ch. 11.10 - Prob. 92PCh. 11.10 - Prob. 93PCh. 11.10 - Prob. 94PCh. 11.10 - Prob. 95PCh. 11.10 - Prob. 96PCh. 11.10 - Prob. 97PCh. 11.10 - Prob. 98PCh. 11.10 - A thermoelectric cooler has a COP of 0.18, and the...Ch. 11.10 - Prob. 100PCh. 11.10 - Prob. 101PCh. 11.10 - Prob. 102PCh. 11.10 - Prob. 103RPCh. 11.10 - Prob. 104RPCh. 11.10 - Prob. 105RPCh. 11.10 - A heat pump that operates on the ideal...Ch. 11.10 - A large refrigeration plant is to be maintained at...Ch. 11.10 - Repeat Prob. 11112 assuming the compressor has an...Ch. 11.10 - A heat pump operates on the ideal...Ch. 11.10 - An air conditioner with refrigerant-134a as the...Ch. 11.10 - An air conditioner operates on the...Ch. 11.10 - Consider a two-stage compression refrigeration...Ch. 11.10 - A two-evaporator compression refrigeration system...Ch. 11.10 - Prob. 116RPCh. 11.10 - Prob. 117RPCh. 11.10 - Prob. 118RPCh. 11.10 - Consider a regenerative gas refrigeration cycle...Ch. 11.10 - Prob. 120RPCh. 11.10 - The refrigeration system of Fig. P11122 is another...Ch. 11.10 - Repeat Prob. 11122 if the heat exchanger provides...Ch. 11.10 - An ideal gas refrigeration system with three...Ch. 11.10 - Derive a relation for the COP of the two-stage...Ch. 11.10 - Prob. 129FEPCh. 11.10 - Prob. 130FEPCh. 11.10 - Prob. 131FEPCh. 11.10 - Prob. 132FEPCh. 11.10 - An ideal vapor-compression refrigeration cycle...Ch. 11.10 - Prob. 134FEPCh. 11.10 - An ideal gas refrigeration cycle using air as the...Ch. 11.10 - Prob. 136FEPCh. 11.10 - Prob. 137FEPCh. 11.10 - Prob. 138FEP
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