Chapter 9, Problem 9.15P

A reversed Carnot cycle required 3 hp andextracts energy from a lake to heat a house. Ifthe house is kept at 70°F and required 2000BTU/min, what is the temperature of the lake?

A dry and saturated steam supplied in a power plant is at 1500 kPa. Determine theefficiencies of Carnot and Rankine cycle if the pressure at the condenser is at 40 kPa,neglecting pump work.

Steam at 20 MPa and 620°C enters a steam turbine and expands to a condenser pressure of 100 kPa. An open feedwater heater is added operating at 2 MPa. Calculate the cycle thermal efficiency in %. Use the unrounded values of the work of the turbine, work of the pump, and heat added when needed. Please use the green book entitled "Thermodynamics Properties of Water Including Vapor, Liquid, and Solid Phases by Keenan, Keyes, Hill, and Moore for the steam table.

From the given data, if refrigerant circulation rate is 0.025kg/s, find the refrigerant effect of the ideal vapour compression cycle.

A Rankine Cycle operates between high and low temperature reservoirs at 1500oC and 25oC respectively. What is the maximum theoretical efficiency of this cycle?

Solve

If a power plant produces steam at 600°C and outputs heat at 150°C to a cogeneration power plant that then outputs its exhaust at a temperature of 40°C. Find the total efficiency of this combination of power plants. Assume both plants are 80% as efficient as a Carnot heat engine.

A regenerative steam power cycle with two feedwater heaters, one closed and one open, as shown in the figure. Steam enters the first stage of the turbine at 12 MPa, 480°C and expands to 2 MPa. Some steam is withdrawn at 2 MPa and fed to the closed feedwater heater. The remainder expands through the second stage turbine at 0.3 MPa, where an additional amount is drawn off and fed to the open feedwater heater operating at 0.3 MPa. Steam expanding through the third-stage turbine leaves at a condenser pressure of 6 kPa.The feedwater leaves the closed heater at 210°C, 12 MPa, and the condensate leaving as a saturated liquid at 2 MPa is trapped in the open feedwater heater. Saturated liquid at 0.3 MPa leaves the open feedwater heater. Assume that all stages of the pumps and turbines operate isentropically. Determine for the cycle:(a) The heat transfer to the working fluid passing through the steam generator, in kJ per kg of steam entering the first-stage turbine.(b) thermal efficiency.(c) the…

A steam plant operate on the cycle of fig 8,4 . the pressure levels are 10 kPa and 6000 kPa, and the steam leaves the turbine as saturated vapor. The pump efficiency is 0.70 and the turbine 0.75. determine the thermal efficiency of the plant