Thermodynamics

A heat transfer requires a temperature difference, see chapter 4, to push the Q.. What implications do that have for a real heat engine? A refrigerator?

A room is heated with an electric space heater on a winter day. Examine the following control volumes, regarding heat transfer and work , including sign. 

(a) The space heater. 

 (b) Room 

(c) The space heater and the room together 

Estimate triple point of water in Fahrenheit, Rankine and Kelvin scales.

The black grille on the back of a refrigerator has a surface temperature of 95 F with a total surface area of 10 ft². Heat transfer to the room air at 70 F takes place with an average convective heat transfer coefficient of 3 Btu/h ft² R. How much energy can be removed during 15 minutes of operation?

A polytropic flow process with n = 0 might be which device? 

Define thermodynamics. Justify that it is the science to compute energy, energy and entropy.

Does a reversible process change the availability if there is no work involved? 

A closed metallic boiler drum of capacity 0.24m³ contain steam at a pressure of 11bar and a temperature of 200ºC. Calculate the quantity of steam in the vessel. At what pressure in the vessel will the steam be dry and saturated if the vessel is cooled?

A mass of 1.5kg of air is compressed in a quasi static process from 0.1Mpa to 0.7Mpa for which PV = constant. The initial density of air is 1.16kg/m³. Find the work done by the piston to compress the air.

A car engine takes atmospheric air in at 70 F, no fuel, and exhausts the air at 0 F producing work in the process. What do the first and the second laws say about that?