a) The efficiency of the engine if it was working reversibly would be:

e = (1 - T_C/T_H) = 0.04859 = w/q_H. Since the amount of heat leaving the hot source and entering the engine per second is 1000000 J, then (0.04859)(1000000 J) = 48590 J of heat will be converted into work per second. This represents a power of 48.6 kW (kilowatts).

b)

The amount of heat being removed per second is 1000000 J. To determine how much water this could cool by one degree C, we use: which can be rearranged to give

That was for one second. For a day we must multiply this by the number of seconds in a day (86400), giving 20.6 million liters per day. This is a cube about 27 meters on a side -- not much really in an ocean. It would probably have little impact on the environment.