Chapter 5, Problem 5.15P

Air is heated at constant pressure from 2 7 degrees C to 57 degrees C at 3 bar in a heater from an infinite heat source at temperature 227 degrees C Find the gain in availability of air and the effectiveness of the heater. Assume To = 280K and Cp =1.0 kj/kgK.

Find the COP of heat pump operating between 300 K and 600K temperature. If the same temperature ranges are used in heat engine, find the efficiency.

/Heat is transferred from a tank of water in a refrigerator at(OC) degrees to a tank of boiling water at (100 C) degrees. With a reversible machine (heat pump). Calculate the Heat drawn from the refrigerator. if it was The heat transferred to the tank of boiling water is 2254kJ.

A closed constant-volume system receives 10Kj of paddle work. The system contains a nitrogen at 340kpa, 5C and occupies 0.1m^3. Find the heat in KJ (Gain or Loss) if the final temperature is 127C. Please use: Q=AU+W (Observe direction) ideal gas equation to find mass table.

A rigid insulated tank is separated into two rooms by a stiff plate. Room A of 0.5 m3 contains air at 250 Kpa, 300 K and room B is 1 m3 has air at 150 Kpa, 1000K. the plate is removed and the air comes to a uniform state without any heat transferred. find the final temp and pressure of the room.

Q.3 Find the increase in unavailable energy associated with transfer of 800kJ of heat from a constant temperature system at 600K to another constant temperature at 400K. The ambient temperature is 300K. A 150kJ В 182kJ C 200kJ D 220kJ

(15%) A small expander (a turbine with heat transfer) has 0.05 kg/s helium entering at 1000 kPa, 550 K and leaving at 250 kPa, 300 K. The power output on the shaft measures 55 kW. Find the rate of heat transfer, neglecting kinetic energies.

A solar collector absorbed 40W/m2 heat from the atmosphere. This is equal to the convection brought by air for drying purpose. If the temperature of the air is 40C while the solar collector area's temperature is 80C and neglecting effect of radiation, find the convective heat transfer coefficient.

Q.4/A combination of a heat engine driving a heat pump, the heat energy supplied to the heat engine is 5040 J, and the temperature of the hot reservoir Tmin is 30 °C and the thermal efficiency of the heat engine is 41%. The work energy W12 of heat engine goes to the heat pump that the coefficient of performance COPHP=1.3. Find: a) The Tmaxmax of the heat engine, b) The Tminmin of the heat pump, c) The work done between two engines d) Qrej of the heat pump T max 150 °C Qadd = 5040 J. W 12 Н.Е. Н.Р. Qrej 30 °C T min