Aheating system musty maintain the interior of a building at 20 degree c during a period when the outside air temperature is 5 degree c and the heat transfer from the building through its roof and walls is 3 x 10^8 kj. for this duty heat pumps are under consideration that would operate between the dwelling and (a) the ground at 15 degree c . (b) a pond at 10 degree c. (c) the outside air at 5 degree c.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Most leaks in reciprocating air compressors can be detected and minimized by: (clo4) a)-detecting leakage areas using ultrasonic acoustic detector. b)-tightening joints and connections c)-replacing faulty equipment d)-all of the given options

Prove the equivalence between the two statements of the 2nd law of thermodynamics (i.e., a violation of one statement leads to the violatio the other statement)