Steam at 7 bar, dryness fraction 0.9, expands reversibly at constant pressure until the temperature is 200 °c. calculate the work input and heat supplied per unit mass of steam during the process.

An air-standard stirling cycle operates with a maximum pressure of 600 psia and a minimum pressure of 10 psia. the maximum volume of the air is 10 times the minimum volume. the temperature during the heat rejection process is 100°f. calculate the specific heat added to and rejected by this cycle, as well as the net specific work produced by the cycle. use constant specific heats at room temperature. the properties of air at room temperature are r

An internally reversible refrigerator has a modified coefficient of performance accounting for realistic heat transfer processes of where qin is the refrigerator cooling rate, qout is the heat rejection rate, and is the power input. show that copm can be expressed in terms of the reservoir temperatures tc and th, the cold and hot thermal resistances rt,c and rt,h, and qin, as where rtot rt,c rt,h. also, show that the power input may be expressed as 1.39 a household refrigerator operates with cold- and hot-temperature reservoirs of tc 5 c and th 25 c, respectively. when new, the cold and hot side resistances are rc,n 0.05 k/w and rh,n 0.04 k/w, respectively. over time, dust accumulates on the refrigerator’s condenser coil, which is located behind the refrigerator, increasing the hot side resistance to rh,d 0.1 k/w. it is desired to have a refrigerator cooling rate of qin 750 w. using the results of problem 1.38, determine the modified coefficient of performance and the required power input w under (a) clean and (b) dusty coil conditions. internally reversible refrigerator qout qin w high-temperature reservoir low-temperature reservoir th th,i tc,i tc high-temperature side resistance low-temperature side resistance w qin th tc qinrtot tc qinrtot copm tc qinrtot th tc

Awalk up the phase change graph worksheet