Consider a thermal storage system in which the phasechange

Chapter 9, Problem 9.90

(choose chapter or problem)

Consider a thermal storage system in which the phasechange material (paraffin) is housed in a large con-tainer whose bottom, horizontal surface is maintainedat Ts?50?C by warm water delivered from a solarcollector.(a) Neglecting the change in sensible energy of the liq-uid phase, estimate the amount of paraffin that is melted over a five-hour period beginning with aninitial liquid layer at the bottom of the container ofthickness si?10 mm. The paraffin of Problems8.47 and 9.57 is used as the phase change materialand is initially at the phase change temperature,Tmp?27.4?C. The bottom surface area of the con-tainer is A?2.5 m2.(b) Compare the amount of energy needed to melt theparaffin to the amount of energy required toincrease the temperature of the same amount of liq-uid from the phase change temperature to the aver-age liquid temperature, (Ts?Tmp)/2.(c) Neglecting the change in sensible energy of theliquid phase, estimate the amount of paraffin thatwould melt over a five-hour time period if the hotplate is placed at the top of the container andsi?10 mm