The vacuum pump is used to create vacuum in the insulated tank of volume equal to 25 m3. initially the tank is filled with air at temperature 300 k and pressure 1 bar. to support the pump 0.05 kw heater was mounted in the tank. find the minimal power of the pump required to empty the tank within 4 hours. assume that the gas which is leaving the tank is at 350 k. the gas constant for the air is 287 j/kg/k and the air is di-atomic gas. what will be the power if no heating elements are used and the air leaving the tank is at ambient temperature equal to 300 k (due to very slow flow)? which solution is better from energetic point of view?