A source of heat at 1000 K transfers 1000 kW of power to a power generation device, while producing 400 kW of useful work. Determine the second law efficiency of the system, if the environment is at 300 K.

Respuesta :

Answer:

The value is [tex]\eta _2 = 0.57[/tex]

Explanation:

From the question we are told that

    The temperature of the heat source is [tex]T_s = 1000 \ K[/tex]

    The amount of power transferred is  [tex]P_s = 1000 \ kW = 1000 *10^{3} \ W[/tex]

      The work produced is  [tex]W = 400 \ kW[/tex]

       The temperature of the environment [tex]T_e = 300 \ K[/tex]

Gnerally the Carnot efficiency of the system is mathematically represented as

        [tex]\eta_c = 1 -\frac{T_e}{T_s}[/tex]

=>    [tex]\eta_c = 1 -\frac{300}{1000}[/tex]

=>      [tex]\eta_c = 0.7[/tex]

Generally the first  law efficiency of the system is mathematically represented as

            [tex]\eta _1 = \frac{W}{P_s}[/tex]

=>         [tex]\eta _1 = \frac{400}{1000}[/tex]  

=>         [tex]\eta _1 = 0.40[/tex]

Generally the second  law efficiency of the system is mathematically represented as

                [tex]\eta _2 = \frac{\eta_1}{\eta_c}[/tex]

=>               [tex]\eta _2 = \frac{0.4}{0.7}[/tex]

=>               [tex]\eta _2 = 0.57[/tex]