The pressure of refrigerant R-22 drops from 14 bar to 3.5 bar by passing through an expansion valve. The temperature of the refrigerant at the inlet of the valve is 28 C. Determine the entropy production and the rate of exergy destruction for unit mass of refrigerant passing through the expansion valve. The temperature of the environment is To = 25 C.

10 kg of co2 is initially contained at 400 kpa and 300 k. the gas constant for carbon dioxide is 189 j/lkg k) and has a specific heat ratio, k, of 1.289. isentropic expansion then occurs until the pressure is 200 kpa. a) determine the initial volume of co2 in m. b) determine the final temperature in k. c) determine the work done by the system during the expansion kl.