A refrigeration system, which can be modelled as being reversible, is to be used to cool...
A refrigeration system, which can be modelled as being reversible, is to be used to cool an air-tight, air-filled cold-room from T1 = 325 K to T2 = 253 K. The volume of air in the room is V = 8 m3, its initial pressure is P1 = 105 Pa, its specific heat capacity at constant volume is cv = 716 J/kgK, and its gas constant is R = 287 J/kgK. Assume that the walls of the room are completely rigid and that there is no heat transfer between the air and the walls. The rate of work transfer INTO the refrigerator is 1 kW and its COP is fixed at a value of 2.4. Calculate the time taken to cool the room from T1 to T2. Give your answer in seconds.
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A refrigeration
system, which can be modelled as being reversible, is to be used to
cool...
4. Refrigeration and air conditioning is quite useful, but it is, in effect, a way to move heat f...
4. Refrigeration and air conditioning is quite useful, but it is, in effect, a way to move heat from a low temperature to a high temperature. Is this possible, given the second law? Answer the following questions below, for R-134a (a common refrigerant), and then state whether you believe refrigeration violates the second law, and why (or why not) a. R-134a arrives to the inside of the refrigerator that you are trying to keep cooled to T- 4°C. The air...
Determine the COP of the gas refrigeration system shown below. The system consists of two ideal...
Determine the COP of the gas refrigeration system shown below. The system consists of two ideal compressors (C1 and C2 two ideal turbines (T1 and T21 and four heat exchangers (HX-1, HX-2, HX-3, and HX-4). Air is the gas of the refrigeration system. Heat is relected from air to the surroundings as it moves through HDX-1 and HX-2. Heat is accepted by air from the cooled spaces as it moves through HX-3 and HX-4. The temperatures and pressures at several...
A gas turbine receives air at temperature T1 = 827 °C and specific volume v, -0.1...
A gas turbine receives air at temperature T1 = 827 °C and specific volume v, -0.1 m®/kg. Air exits the turbine at P2 = 3 bar and T2 = 450 °C. The volumetric flow rate of air at the inlet is 0.5 m/s. The power output on the shaft is 1900 kW. Determine: The pressure of air at the inlet (pa) in kPa [2 marks] b) The mass flow rate in kg/s [1 mark] c) Find the rate of heat...
1)(Hint: Cp=1.005 kJ/kg-K, Cv=0.718 kJ/kg-K, R=0.287 kJ/kg-K). An air-tight room contains 80 kg of air, and...
1)(Hint: Cp=1.005 kJ/kg-K, Cv=0.718 kJ/kg-K, R=0.287 kJ/kg-K). An air-tight room contains 80 kg of air, and a 2-kW baseboard electric resistance heater in the room is turned on and kept on for 15 min. The temperature rise of air at the end of 15 min is 2)An example of when it is appropriate to model a substance as an ideal gas is when a. The pressure and temperature are close to the critcal point b. The pressure and temperature are...
B2 The University has decided to commission a large iconic sculpture which is to be erected in place of the old library. The structure is intended to acknowledge the industrial heritage of the region...
B2 The University has decided to commission a large iconic sculpture which is to be erected in place of the old library. The structure is intended to acknowledge the industrial heritage of the region whilst at the same time linking to the University's motto "Per Ardua Ad Alta" (through efforts to high things"). An (unimaginative) artist is suggesting that a large circular chimney (diameter D, height h) should be built using the bricks from the old library. Concern has been...
summarizr the followung info and write them in your own words and break them into different...
summarizr the followung info and write them in your own words and break them into different key points. 6.5 Metering Chamber: 6.5.1 The minimum size of the metering box is governed by the metering area required to obtain a representative test area for the specimen (see 7.2) and for maintenance of reasonable test accuracy. For example, for specimens incorporating air spaces or stud spaces, the metering area shall span an integral number of spaces (see 5.5). The depth of...
summatize the following info and break them into differeng key points. write them in yojr own...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
4. Refrigeration and air conditioning is quite useful, but it is, in effect, a way to move heat from a low temperature to a high temperature. Is this possible, given the second law? Answer the following questions below, for R-134a (a common refrigerant), and then state whether you believe refrigeration violates the second law, and why (or why not) a. R-134a arrives to the inside of the refrigerator that you are trying to keep cooled to T- 4°C. The air...
Determine the COP of the gas refrigeration system shown below. The system consists of two ideal compressors (C1 and C2 two ideal turbines (T1 and T21 and four heat exchangers (HX-1, HX-2, HX-3, and HX-4). Air is the gas of the refrigeration system. Heat is relected from air to the surroundings as it moves through HDX-1 and HX-2. Heat is accepted by air from the cooled spaces as it moves through HX-3 and HX-4. The temperatures and pressures at several...
A gas turbine receives air at temperature T1 = 827 °C and specific volume v, -0.1 m®/kg. Air exits the turbine at P2 = 3 bar and T2 = 450 °C. The volumetric flow rate of air at the inlet is 0.5 m/s. The power output on the shaft is 1900 kW. Determine: The pressure of air at the inlet (pa) in kPa [2 marks] b) The mass flow rate in kg/s [1 mark] c) Find the rate of heat...
B2 The University has decided to commission a large iconic sculpture which is to be erected in place of the old library. The structure is intended to acknowledge the industrial heritage of the region whilst at the same time linking to the University's motto "Per Ardua Ad Alta" (through efforts to high things"). An (unimaginative) artist is suggesting that a large circular chimney (diameter D, height h) should be built using the bricks from the old library. Concern has been...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
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