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HEAT+MASS TRANSFER:FUND.+APPL.
- (a) In the thermodynamic laboratory, student Ali prepared a piston-cylinder device which contains refrigerant-134a at 1000 kPa and 50°C. The mass of the refrigerant is 6 kg. The next step of the experiment involves cooling the refrigerant at constant pressure until its state become liquid at 24°C. Show the process on T-v diagram and determine the heat loss from the system. (b) A heat exchanger as shown in Figure 1 is used to cool water flowing in at 1 kg/s water, 10 kPa and quality 0.95 to saturated liquid at 10 kPa. The cooling fluid is water taken from a lake at 20°C and it exit the heat exchanger at 30°C. Calculate the flow rate of cooling water. Assume that the heat exchange is well insulated and there is no heat loss. Lake water Figure 1: Heat exchangerarrow_forward3. A piston-cylinder device contains 6 kg of refrigerant-134a at 800 kPa and 50°C. The refrigerant is now cooled at constant pressure until it exist as a liquid at 24°C. Show the process on T-v diagram and determine the heat loss from the system. State any assumption made.arrow_forwardInitially, 200 L of saturated vapor refrigerant-134a in a piston. The piston is free to move, and its mass is such that it maintains a pressure of 900 kPa on the refrigerant. The refrigerant is now heated until its temperature rises to 60°C. The work done during this process is Select one: 73.55 kJ 37.55 kJ 27.49 kJ O 72.49 kJarrow_forward
- 6. A well-sealed room contains 60 kg of air at 200 kPa and 25°C. Now solar energy enters the room at an average rate of 0.8 kJ/s while a 120-W fan is turned on to circulate the air in the room. If heat transfer through the walls is negligible, Solve for the air temperature in the room in 30 min. (3 DECIMAL IN FINAL ANSWER PLS)arrow_forwardQ1/ A frictionless piston–cylinder device initially contains 200 L of saturated liquid refrigerant-134a. The piston is free to move, and its mass is such that it maintains a pressure of 900 kPa on the refrigerant. The refrigerant is now heated until its temperature rises to 70°C. Calculate the work done during this process. Answer: 5571 kJarrow_forwardRefrigerant-134a (R-134a) enters the expansion valve of a refrigeration system at 650 kPa with a quality of 20%. The pressure of R-134a at the outlet is 200 kPa. a)Determine the temperature of R-134a at the outlet in oC. Calculate the difference of internal energy between the outlet and inlet in kJ/kgarrow_forward
- A certain quantity of air in a closed vessel with a fixed volume of 0.15 m3 exerts 1 MPa pressure at 500 K. If the vessel is cooled while the pressure is reduced to 350 kPa, determine the heat transfer during the process.arrow_forwardNOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. A piston-cylinder device initially contains 1 kg saturated liquid water at 200°C. Now heat is transferred to the water until the volume quadruples and the cylinder contains saturated vapor only. The saturated liquid properties of water at 200°C 3 are vf= 0.001157 m³/kg and uf= 850.46 kJ/kg (Table A-4). Water 71 kg 200°C Q Determine the internal energy change of the water. The change in internal energy is kJ.arrow_forwardThermodynamics: A rigid cylinder is filled with refrigerant-134a at 18°C. At this state, 40 percent of the mass is vapor. A valve at the bottom is opened, and refrigerant is withdrawn outside.Heat is transferred to the tank such that the temperature in the tank remains constant and the refrigerant fills the tank all the time (V1= V2). Determine the amount of heat that must be transferred by the time one-fourth of the total mass has been withdrawn. The tank volume is 0.1-m3. Clearly show work.arrow_forward
- 1- A piston-cylinder device whose piston is resting on top of stops initially contains 0.5 kg of helium gas at 100 kPa and 25°C. The mass of the piston is such that 500 kPa of pressure is required to raise it. (1) How much heat must be transferred to the helium before the piston starts rising and (2) show the process on P-V diagram 2- A mass of 5 kg of saturated liquid water at 200 kPa is heated at a constant pressure until the temperature reaches 300°C. Find: (1) Au,Ah & Av, (2) the work done during this process, (3) the amount of heat added to the system, and (4) show the process on T - v diagramarrow_forwardA piston-cylinder device whose piston is resting on top of a set of stops initially contains 0.6 kg of helium gas at 100 kPa and 25°C. The mass of the piston is such that 500 kPa of pressure is required to raise it. How much heat must be transferred to helium before the piston starts rising? The specific heat of helium at room temperature is cy= 3.1156 kJ/kg-K (Table A-2). The amount of heat to be transferred to helium is kJ.arrow_forwardA frictionless piston-cylinder device initially contains 200L of saturated liquid refrigerant-134a. The piston is free to move and its mass is such that it maintains a pressure of 900 kPa on the refrigerant. The refrigerant is now heated until its temperature rises to 70C. Calculate the work done during this process. ANS. 5571 KJA fixed mass of an ideal gas is heated from 50 to 80°C at a constant pressure of (a) 1 atm and (b) 3 atm. For which case do you think the energy required will be greater?arrow_forward
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