A successful California engineer has installed a circular hot tub in his backyard and finds that, for the typical operating conditions shown in the sketch, water must be added at a rate of 0.001 kg/s to maintain a fixed water level in the tub.
If the tub is well insulated on its sides and bottom and if the temperature of the makeup water is equal to that of the tub water, at what rate must electrical heaters supply energy to maintain the tub water at 310 K?