What is the maximal coefficient of performance of a refrigerator which cools down 10 kg of water (and then ice) to -6c. upper heat source of this refrigerator is surroundings at constant temperature 21c. initially water is in equilibrium with surroundings. what is maximal coefficient of performance of heat pump operating in the same configuration. specific heat of water, specific heat of ice, and latent heat of fusion are equal to 4.19kj/kg/k, 2.1kj/kg/k and 335 kj/kg, respectively.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater

Which of the following ziegler nichols tuning methods the response of the controller to a step input should exhibit an s-shaped curve? a)-open loop mode b)-closed loop mode c)-both modes (open & closed) d)-none of the modes (open & closed)

An engine runs on the ideal diesel cycle. the cycle has a compression ratio of 20 and a cutoff ratio of 2. the highest temperature in the cycle is 1200 k. if the heat into the system is 300 kj/kg of working fluid and using variable specific heats determine the work produced per mass of working fluid