When the water is heated for a period of time, the temperature of the water rises gradually from an initial temperature of 25°C. When the temperature starts to rise initially, the balloon is deflated further. After heating for a period of time, the balloon becomes fully inflated as shown in Fig. 8.2. (i) Explain why the balloon deflated further when the temperature starts to rise.
(ii) Explain why the balloon becomes fully inflated as shown in Fig. 8.2.

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)