As shown in the figure, an air conditioner operating at steady state maintains a dwelling at 70°F on a day when the outsidetemperature is 103.5°F. The rate of heat transfer into the dwelling through the walls and roof is 30,000 Btu/h and the net power inputto the air conditioner compressor is 3.45 hp.Step 1BInside, 70° FDetermine the coefficient of performance for the air conditioner.=Evaporatori30,000 Btu/hDetermine the coefficient of performance of the air conditioner. Determine the power input required, in hp, and the coefficient ofperformance for a reversible air conditioner providing the same cooling effect while operating between the same cold and hottemperatures.Refrigerant loopCompressorOutsideQ +Condenser

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As shown in the figure, an air conditioner operating at steady state maintains a dwelling at 70°F on a day when the outside temperature is 103.5°F. The rate of heat transfer into the dwelling through the walls and roof is 30,000 Btu/h and the net power input to the air conditioner compressor is 3.45 hp. Inside, 70° F Evaporator 30,000 Btu/h Refrigerant loop Compressor Outside Condenser Qu Determine the coefficient of performance of the air conditioner. Determine the power input required, in hp, and the coefficient of performance for a reversible air conditioner providing the same cooling effect while operating between the same cold and hot temperatures.

As shown in the figure, an air conditioner operating at steady state maintains a dwelling at 70°F on a day when the outside temperature is 103.5°F. The rate of heat transfer into the dwelling through the walls and roof is 30,000 Btu/h and the net power input to the air conditioner compressor is 3.45 hp. Inside, 70° F Evaporator 30,000 Btu/h Refrigerant loop Compressor Outside Condenser Qu Determine the coefficient of performance of the air conditioner. Determine the power input required, in hp, and the coefficient of performance for a reversible air conditioner providing the same cooling effect while operating between the same cold and hot temperatures.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.46P

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As shown in the figure, an air conditioner operating at steady state maintains a dwelling at 70°F on a day when the outside temperature is 102°F. The rate of heat transfer into the dwelling through the walls and roof is 30,000 Btu/h and the net power input to the air conditioner compressor is 3.4 hp. Inside, 70° F Evaporator ← 30.000 Bu Refrigerant loop W. Compressor Outside Condonsor Que Determine the coefficient of performance of the air conditioner. Determine the power input required, in hp, and the coefficient of performance for a reversible air conditioner providing the same cooling effect while operating between the same cold and hot temperatures.
1- A boiler plant comprises a boiler, superheater, economizer and air preheater. The feedwater enters the economizer at 45 °C. Air is preheated from a temperature of 15 °C to 150 °C. The steam is generated in the boiler at a pressure of 35 bar, 0.98 dry and leaves the superheater at 350 °C. When using oil of calorific value 42 MJ/kg, the evaporation rate is 10 kg steam per kg fuel and the air to fuel ratio is 20: 1 by mass. Neglecting heat losses and pressure drops, estimate the heat transfer per kg fuel in each component and the plant efficiency. Assume cp for air and flue gas as 1.005 and 1.045 kJ/ kg K, respectively.
Referring to the reversible heat pump cycle shown in the figure, p1 = 14.7 Ibf/in?, p4 = 27.8 lbf/in?, v1 = 12.6 ft³/Ib, v4 = 8.0 ft³/lb, and the gas is air obeying the ideal gas model. P4 pi TH V4 VI Determine TH, in °R, and the coefficient of performance. Step 1 Determine TH, in °R. TH = °R Save for Later Attempts: 0 of 1 used Submit Answer Step 2 The parts of this question must be completed in order. This part will be available when you complete the part above.
-Gas supply line- Gas A 1.5 m3 tank initially contains a gas at 140 kPa, 340 K. The tank is connected a line carrying same gas at 1400 kPa and 340 K. What should be heat transfer during this process, in kJ, so that the final pressure and temperature are 1400 kPa and 340 K, respectively. (cp=0.72 kJ/kg.K, cv=0.48 kJ/kg.K).
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
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Referring to the reversible heat pump cycle shown in the figure, p₁ = 14.7 lb/in², p4 = 20.3 lb/in², v₁ = 12.6 ft³/lb, v4 = 10.0 ft³/lb, and the gas is air obeying the ideal gas model. P4 P1 Determine TH, in °R, and the coefficient of performance. V4 VI TH V
An air conditioner is a device used to cool the inside of a home. It is, in essence, a refrigerator in which mechanical work is done and heat removed from the (cooler) inside and rejected to the (warmer) outside. A home air conditioner operating on a reversible Carnot cycle between the inside, absolute temperature T2, and the outside, absolute tempera- ture T1 > T2, consumes P joules/sec from the power lines when operating continuously. (a) In one second, the air conditioner absorbs Q2 joules from the house and rejects Q1 joules outdoors. Develop a formula for the efficiency ratio Q2/P in terms of T1 and T2. (b) Heat leakage into the house follows Newton's law Q = A(T, – T2). Develop a formula for T, in terms of T1, P, and A for continuous operation of the air conditioner under constant outside temperature T and uniform (in space) inside temperature T2. (c) The air conditioner is controlled by the usual on-off thermostat and it is observed that when the thermostat set at 20°C and an…
Referring to the reversible heat pump cycle shown in the figure, p₁ = 14.7 lb/in², p = 41.5 lb/in², v₁ = 12.6 ft³/lb, v4 = 6.0 ft³/lb, and the gas is air obeying the ideal gas model. Step 1 Determine TH, in °R, and the coefficient of performance. Determine TH, in °R. TH= i P4 ºR P1 V4 VI 3 Tμ V
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 vapor-compression refrigeration system operates on the cycle shown below. The refrigerant is tetrafluoroethane. For the following set of operating conditions, determine the circulation rate of the refrigerant, the heat-transfer rate in the condenser, the power requirement, the coefficient of performance of the cycle, and the coefficient of performance of a Carnot refrigeration cycle operating between the same temperature levels. Use the table containing the properties of saturated 1,1,1,2-tetrafluoroethane (R134A) and the PH diagram for tetrafluoroethane (HFC-134a). (Include a minus sign if required.) T S Vapor-compression refrigeration cycle. Evaporation T= -12°C Condensation T = 26°C n(compressor) = 0.77 Refrigeration rate = 400 kJ-s¯1 4 Throttle valve Condenser 3 Compressor Evaporator 2