The exhaust gas regenerator (counter-flow heat exchanger) for a gas turbine handles 1.9 kg/sec of air from its compressor and heats it by means of 2.2 kg/sec of hot exhaust gas. Exhaust gas enters the regenerator at 596°C and leaves at 312°C. Compressed air enters the regenerator at 220°C. For this temperature range a constant pressure specific heat for the exhaust has may be estimated at 1090 J/kg-°C. Assume no heat transfer other than between the generator fluids. Determine the log mean temperature difference for the exchanger, °C A. 16.98 B. 26.98 C. 36.98 D. 46.98

The exhaust gas regenerator (counter-flow heat exchanger) for a gas turbine handles 1.9 kg/sec of air from its compressor and heats it by means of 2.2 kg/sec of hot exhaust gas. Exhaust gas enters the regenerator at 596°C and leaves at 312°C. Compressed air enters the regenerator at 220°C. For this temperature range a constant pressure specific heat for the exhaust has may be estimated at 1090 J/kg-°C. Assume no heat transfer other than between the generator fluids. Determine the log mean temperature difference for the exchanger, °C A. 16.98 B. 26.98 C. 36.98 D. 46.98

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 12RQ: Refrigerators currently being manufactured in the United States are using______as their refrigerant.

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Welded ______sealed compressors are normally used in household refrigerators.
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Steam passes steadliy through a turbine and condenser as shown in the figure below. After expanding through the turbine and producing 1000kW of power, the steam is at a pressure of 0.08 bar and a quality of 87.4%; it enters a shell-and-tube heat exchanger where the steam now condenses on the outside of tubes through which cooling water flows; this condensate continues to flow, finally exiting as saturated liquid at 0.08 bar. The mass flow rate of the condensing steam is 58kg/s, In order to condense the steam, cooling water enters the tubes at 15°C and flows as a separate stream to exit at 35°C with negligible change in pressure. Stray heat transfer is negligible as are kinetic and potential effects. Considering the steam inside the turbine as a system, is the system best described as open, closed or isolated? What is the mass flow rate of steam entering the turbine in kg/s? What is the enthalpy at the inlet of the turbine in k/kg? What is the mass flowrate of the cooling water in kg/s?…
Part C A surface condenser is required to condense 30,000 kg of dry steam per hour at a pressure of 0.04 bar at 29°C. The cooling water enters at 15°C and leaves at 27°C. Assume the overall surface area (As) of the tube is 1200 m² If the velocity of water in the tubes should not exceed 2 m/s, the outside diameter of the tube is 0.025 m and the inside diameter is 0.022 m, determine (i) the heat transfer (ii) mass of cooling water circulated (iii) the number of tubes (iv) the length of each tube and (v) the overall heat transfer coefficient of the tubes. Take the density of water =1000 kg/m3 and specific heat of water =4.187 kJ/kg K.
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