Concept explainers
If cold outside air at 20 F is leaking into a 20-ft by 30-ft by 10-ft room where the heating system is trying to maintain a comfortable temperature of 72 F, then the same amount of air might be assumed to be leaking out of the room. If one were to estimate that this rate of leakage amounted to about 0.4 air changes per hour (see Problem 1-19), what load would this leakage place on the heating system, in Btu/hr? Assume that the air lost is at the assumed room comfort temperature and is replaced by the cold outside air. Assume an air density of 13.5 cubic feet per pound mass and
Want to see the full answer?
Check out a sample textbook solutionChapter 1 Solutions
Heating Ventilating and Air Conditioning: Analysis and Design
Additional Engineering Textbook Solutions
DeGarmo's Materials and Processes in Manufacturing
Introduction To Finite Element Analysis And Design
Engineering Mechanics: Statics
Automotive Technology: Principles, Diagnosis, and Service (5th Edition)
Thinking Like an Engineer: An Active Learning Approach (3rd Edition)
Mechanics of Materials (10th Edition)
- 4. Oxygen supply for a lung related deficiency is supplied to patients from bottled oxygen in gaseous form. The oxygen bottles are considered empty when they are at 2 bar absolute (and at a room temperature of 20 °C) and are filled from a large source of gaseous oxygen at 210 bar absolute and 10 °C and the valve filling the cylinder is closed when the pressure in the cylinder reaches 200 bar absolute. If the heat transfer during the filling process is negligibly small and neglecting velocity and height contributions, calculate the final temperature of the oxygen in the cylinder at the moment of filling valve closure and the mass of oxygen filled into the cylinder. Take the internal volume of the cylinder to be 15 litre. If the cylinder eventually comes to thermal equilibrium with the surroundings at 20 °C what is the final pressure of the oxygen in the cylinder.arrow_forwardMethane enters a compressor at 14 psia with a very low velocity and is compressed to 55 psia. The entering methane has a density of 0.04 lbm/ft. The methane leaves the compressor with a velocity of 250 fps. The flow rate is 0.38 lbm/s. Assuming a quasiequilibrium process in which pu calculate the work done on the methane in hp. 1.33-constant, [ans: -57.4 hp]arrow_forwardT10 please help me with the answer and full solutionarrow_forward
- I need the answer as soon as possiblearrow_forwardFor an ideal gas, the decrease in internal energy of 1.4 kgm is -343 kJ when the volume increases from 0.043 cu. Meters to 0.13 cubic meters and the pressure decreases from 0.07 bar to 0.02 bar; Cv= 0.72 kJ/kgm K. Compute the change in enthalpy, T1, and T2arrow_forwardI need the answer as soon as possiblearrow_forward
- The vacuum in a condenser is found to be 71.12 cm of Hg (barometer 76 cm of Hg) and the temperature is 30°C. To find the weight of air present per kg of uncondensed steam.arrow_forwardDuring processing in a steel mill, a 375kg steel casting at 800 degrees is quenched by plunging it into a 500-gal oil bath, which is initially 75 degrees . After the casting cools and the oil bath warms , what is the final tempertature of the two? The weight per unit volume of the oil is 7.5 lb/gal.arrow_forwardAnswer the following questions regarding vessels:arrow_forward
- A rigid tank filled with water is divided into two chambers by a membrane. The membrane is a perfect insulator and there is no heat transfer between the chambers. The volume of the water in chamber A and chamber B is VA = 1 m² and Vg = 4 m³, respectively. Initially (state 1) chamber A contains water at a temperature of 150 °C and a pressure of 350kPa. Chamber A also contains a plate of nickel with a mass of myi = 20 kg that is always in thermal equilibrium with the water. Chamber B contains 40 kg of water at a temperature of 80 °C. The membrane ruptures and heat transfers between the tank and its surroundings such that the water inside the tank reaches a uniform state, with a final temperature, T2, of 100°C. The specific heat of nickel is CpNi = 0.44 kJ/kg-K. c) Determine the pressure and specific internal energy of the water at the final state. (ie. P, and uz) d) Determine total heat transfer (between the tank and its surroundings) during the process. (ie. 1Q2) A В (Water) (Water)…arrow_forwardA rigid tank of 20ft contains air at 100psia and 70°F. The tank is equipped with a relief valve that opens at a pressure of 125psia and remains open until the pressure drops to 120psia. If a fire causes the valve to operate, what is the quantity (Ibm) of air lost due to the fire?arrow_forwardt=100°C h= 400 kJ/kg What is the state of the pure substance?arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY