A power plant must produce a steady mechanical output of 1.5MW. The boiler supplies heat at TH=700K, while environmental regulations limit the rate at which heat may be discharged into the river at TC=300K to 4.0×103kJh−1.
(i) Show that the minimum rate of heat input required from the boiler is determined by the maximum theoretical efficiency between the stated temperatures.
(ii) Calculate this minimum heat input rate in kJs−1.
(iii) Using energy balance, find the corresponding minimum rate at which heat would be rejected to the environment.
(iv) The actual plant is expected to operate at 60% of the Carnot efficiency. Determine whether it can meet the environmental discharge limit. If it exceeds the limit, calculate by how much and suggest the additional cooling requirement.