Molecular Physics | Thermodynamics Answers

A 500 MW steam power plant consumes coal at a rate of 65 tons/h. If the heating value of the coal is 30,000 kJ/kg, what is the overall efficiency of this plant? 

A steam power plant burns coal to produce a 600 MW net power with an overall thermal efficiency of 45 percent. The actual air-fuel ratio in the furnace is calculated to be 12 kg air/kg fuel. The heating value of the coal is 30,000 kJ/kg. 

(i)  What is the rate and amount of coal consumed during a 24-hour period?

(ii) What is the rate of air flowing through the furnace? 

A solar collector for a hot water system absorbs solar radiation at the rate of 660 W/m Its collecting area is 3.8 m². Cold water at 15°C enters the collector. What volume of water per minute at an output temperature of 60°C can this collector deliver?

A polytropic process of air from 1034 kPa, 149 deg. C and 0.028 m3 occurs to 138 kPa in accordance with pV1.3 = C. Determine

(a) the final temperature in deg. C

(b) the change in internal energy in kJ

(c) the work nonflow in kJ

(d) the heat in kJ from the formula using polytropic specific heat

A polytropic process of air from 1034 kPa, 149 deg. C and 0.028 m3 occurs to 138 kPa in accordance with pV1.3 = C. Determine:

(a) the final temperature in deg. C

(b) the change in internal energy in kJ

(c) the work nonflow in kJ

(d) the heat in kJ from the formula using polytropic specific heat

0.5 kg of an ideal gas undergoes an isentropic process from 657 kPa gage and a volume of 0.017 cubic meter to a final volume of 0.1 cubic meter. If Cv = 0.384 kJ/kg-K and Cp = 0.52 kJ/kg-K, calculate:

a) the final temperature in deg. C

b) the final pressure in kPa

c) the change in enthalpy in kJ

d) the work nonflow in kJ

While the temperature remains constant at 38 deg. C, 2.5 kg of a certain ideal gas whose Cp = 1.1724 kJ/kg-K, Cv = 0.8375 kJ/kg-K rejects 300kJ of heat. If p1 = 586kPa, determine:

(a) the final pressure in kPa

(b) the initial volume in cubic meter

(c) the final volume in cubic meter

A perfect gas has a value of R = 316 J/kg-K and k = 1.26. If 21 kJ of heat are added to 2.5 kg of this gas during an isometric process when the initial temperature is 32 deg. C, determine:

(a) the final temperature in deg. C

(b) the change in enthalpy in kJ

(c) the change in entropy in kJ/K

 If 528 kJ of heat are added to 2.25 kg of helium at constant volume process when the initial temperature is 40 deg. C, find:

a) the final temperature in deg. C

b) the change in enthalpy in kJ

c) the change in entropy in kJ/K

Calculate the final volume of 0.4 m³ of an experimental gas which is compressed according to the law PV^y=C the initial gas pressure is increase by factor of seven and γ=1.5 give the answer to 4 decimal places