Question

An inventor proposes an engine that operates between the 27 deg C warm surface layer of the ocean and a 10 deg C layer a few meters down. The claim is that this engine can produce 100 kW at a flow of 20 kg/s. Is this possible?

Answer 1

Engine not possible

Step-by-step explanation:

source temperature T1 = 300 K

sink temperature T2= 283 K

therefore, carnot efficiency of the heat engine

η= 1- T_2/T_1

`\eta= 1-(T_1)/(T_2)`

`\eta= 1-(283)/(300)`

= 0.0566

= 5.66%

claims of work produce W = 100 kW, mass flow rate = 20 kg/s

`Q=mc_p(T_1-T_2)`

`Q=20*4.18(300-283)`

= 1421.2 kW

now
`\eta= \frac{W}Q}`

now
`\eta= (100)/(1421.2)`

=7%

clearly, efficiency is greater than carnot efficiency hence the engine is not possible.