Air enters the compressor of an ideal Brayton refrigeration cycle at 100 kPa, 300 K, with a volumetric flow rate of 0.90 m3/s, and is compressed to 430 kPa. The temperature at the turbine inlet is 330 K. Determine: (a) The net power input, in kW (b) The refrigerating capacity, in kW. (c) The coefficient of performance. (d) The coefficient of performance of a reversible refrigeration cycle operating between reservoirs at TC = 300 K and TH = 330 K.

Air enters the compressor of an ideal Brayton refrigeration cycle at 100 kPa, 300 K, with a volumetric flow rate of 0.90 m3/s, and is compressed to 430 kPa. The temperature at the turbine inlet is 330 K. Determine: (a) The net power input, in kW (b) The refrigerating capacity, in kW. (c) The coefficient of performance. (d) The coefficient of performance of a reversible refrigeration cycle operating between reservoirs at TC = 300 K and TH = 330 K.

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

Chapter28: Special Refrigeration Applications

Section: Chapter Questions

Problem 15RQ: Why is two-stage compression popular for extra-low-temperature refrigeration systems?

See similar textbooks

Similar questions

Please help!!!! Refrigerant 22 enters the compressor of an ideal vapor-compression refrigeration system as saturated vapor at -30°C with a volumetric flow rate of 10 m3/min. The refrigerant leaves the condenser at 19°C, 9 bar. Determine: (a) the magnitude of the compressor power, in kW. (b) the refrigerating capacity, in tons. (c) the coefficient of performance. (d) the rate of entropy production for the cycle, in kW/K. Answer for part (a): 52 kW Answer for part (b): 59 tons Answer for part (c): 3.98 Please answer part also d! That's the part I also need. Thank you!
Problem 1 In a Rankine Thermodynamic cycle, steam leaves the boiler and enters the turbine at 600 psia, 800 °F. The condenser pressure is 1 psia. After presenting a schematic of the problem in addition to clearly labeled and explained T-s and h-s diagrams, you are asked to determine the following: (a) Pump work required per Ibm of working fluid. Quality of fluid at turbine inlet. Work output of turbine per lbm of working fluid. Energy input to the boiler per lbm of working fluid. Heat rejection by the condenser per Ibm of working fluid. Determine the cycle thermal efficiency. (d) (e) (f)
Steam is supplied to a two-stage turbine at 48 bar and 400 °C. It expands in the first turbine until it is just dry saturated, then it is re-heated to 400 °C and expanded through the second-stage turbine. The condenser pressure is 0.04 bar. High-P turbine Low-P turbine Reheater - Boiler P4= P3 = Preheat Condenser Determine thespecific work outputof the system to 3 d.p.?
In an ideal gas refrigeration cycle, helium enters the compressor at a temperature of 15 ̊C and a pressure of 100 kPa and leaves at a pressure of 300 kPa. The temperature of helium at the turbine inlet is 30 ̊C. Assuming that the isentropic efficiency of the compressor and turbine is 80%; Calculate a) the lowest and highest temperatures of the cycle, b) the efficiency coefficient of the cycle, c) the required helium flow rate for 5 kW cooling capacity
**** PART C ONLY In a standard ideal refrigeration cycle (Fig. 1), the refrigerant 134a enters adiabatically isolated expansion valve as a saturated liquid at a pressure P1 = 1 MPa and leaves the device at a pressure P2 = 100kPa. Then the refrigerant enters the evaporator, where it changes into the saturated vapor. Subsequently, the vapor is compressed in an isentropic compressor to the pressure 1MPa and condensed in the condenser back to the initial saturated-liquid state. USE IMAGE BELOW FOR PART C
****PART B ONLY In a standard ideal refrigeration cycle (Fig. 1), the refrigerant 134a enters adiabatically isolated expansion valve as a saturated liquid at a pressure P1 = 1 MPa and leaves the device at a pressure P2 = 100kPa. Then the refrigerant enters the evaporator, where it changes into the saturated vapor. Subsequently, the vapor is compressed in an isentropic compressor to the pressure 1MPa and condensed in the condenser back to the initial saturated-liquid state. PART B - To increase the efficiency of the cycle, the expansion valve is replaced by an isentropic turbine.Forthismodifiedcycle,determinetheworkwo′utproducedbytheturbineandthe heat qL′ absorbed by the refrigerant in the evaporator (per 1 kg of the refrigerant).
Air enters the compressor of an ideal Brayton refrigeration cycle at 100 kPa, 300 K. The compressor pressure ratio is 3.75, and the temperature at the turbine inlet is 350 K. Determine: (a) net work input, per unit mass of air flow, in kJ/kg. (b) refrigeration capacity, per unit mass of air flow, in kJ/kg. (c) coefficient of performance. (d) coefficient of performance of a Carnot refrigeration cycle operating between thermal reservoirs at T_C 5 300 K and T_H 5 350 K, respectively
Air within a piston-cylinder assembly executes a Carnot heat pump cycle, as shown in the figure below. For the cycle, TH = 500 K and Tc = 300 K. The energy rejected by heat transfer at 500 K has a magnitude of 1000 kJ per kg of air. The pressure at the start of the isothermal expansion is 325 kPa. Tc. 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.
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
A compound compression system below, Sketch (ph) diagram for cycle and calculate : 1. Total compressor work. 2. Q condenser 3. Enthalpy drops of refrigerant after sub-cooler 3 Water inter cooler Refrigerant (working fluid) R717 Low Cycle Pressure 1.8 bar Intermediate Cycle Pressure 4 bar T3= 40 °C Low stage compressor High stage compressor Ts= 50 °C Evaporator Qwraporation=1130 kJ/kg Expansion valve Condenser Sub-cooler
A reheat cycle with two stages of reheating is executed with steam expanding initially from 200 bar (20 Mpaa) and 540 deg C. The 2 reheater pressures are 40 bar (4 Mpaa) and 10 bar (1 Mpaa) and the steam leaves each reheater at 540 deg C. Steam is bled in between two reheating sessions at a pressure equal to 20 and 15 bars into 2 open feedwater heaters. Condensation occurs at 60 deg C. All expansion and compression efficiencies are 93 %. There is a total of 4.5+ (3*25/100) kg/sec of steam circulated in the cycle. Answer the following: fill up the blanks in the items below: 1. Equipment layout and TS diagram for the cycle 2. Actual mass of steam bled into the open heater m1'= kg/kg for the _kg/sec for the heater nearest to the SGU/boiler and m2' = heater nearest to the condenser. 3. Actual turbine work in KW Answer: 4. Energy Chargeable (actual) Answer: 5. Ideal Rankine engine efficiency % Answer:
A reheat cycle with two stages of reheating is executed with steam expanding initially from 200 bar (20 Mpaa) and 540 deg C. The 2 reheater pressures are 40 bar (4 Mpaa) and 10 bar (1 Mpaa) and the steam leaves each reheater at 540 deg C. Steam is bled in between two reheating sessions at a pressure equal to 20 and 15 bars into 2 open feedwater heaters. Condensation occurs at 60 deg C. All expansion and compression efficiencies are 90 %. There is a total of 10.3 kg/sec of steam (total mass flow rate m) circulated in the cycle. Answer the following: fill up the blanks in the items below: Equipment layout and TS diagram for the cycle. Ideal turbine work (KW) Ans:_______________________________ Actual mass of steam bled into the open heater m1’= _____________kg/sec for the heater nearest to the SGU/boiler and m2’ = _____________________kg/sec for the heater nearest to the condenser. Actual engine efficiency (%) Answer: _______________________ Actual Rankine cycle efficiency %…