Two tanks, each having a volume of 1 m3, are connected by a valve and a pipe, as shown below. Tank A is filled with R-134a at 20C with a titer of 15%. Tank B is empty. The valve is then opened and saturated steam flows from A to B. How much heat must be transferred to the R-134a so that the two tanks only contain saturated steam at the end?

Answer should be : Q = 25 510 kJ