Consider an enclosed swimming pool. The pool area has a sensible heat loss of 424,000 Btu/hr (124 kW) and a latent heat gain of 530,000 Btufhr (155 kW) on a design day when the outdoor air is at 35 F (2 C) and 20 percent relative humidity (RH). The space is to be maintained at 75 F (24 C) and 50 percent RH. Outdoor air is to be heated to 60 F (16 C), mixed with recirculated air from the conditioned space and the mixed air heated to supply conditions. (a) At what rate, in cfm, is the air supplied to the space if the supply air temperature is 95 F (35 C)? (b) At what rate, in cfm, is outdoor air and recirculated air flowing? (c) What is the heat transfer rate for the preheat process? (d) What is the heat transfer rate for the mixed air heating process?
Want to see the full answer?
Check out a sample textbook solutionChapter 3 Solutions
HEATING, VENTILATING,+AC ANAL...EBOOK>I<
Additional Engineering Textbook Solutions
Thinking Like an Engineer: An Active Learning Approach (3rd Edition)
Engineering Mechanics: Statics
Applied Fluid Mechanics (7th Edition)
Engineering Mechanics: Statics & Dynamics (14th Edition)
Introduction to Heat Transfer
- A summer air conditioning system (schematic shown below) consisting of a cooling coil and a reheat coil, supplies air to a space maintained at 26°C db-temperature and 19°C wb-temperature. The sensible and latent heat loads on the space are both 18 kW and 18 kW, respectively. The conditions of the air leaving the cooling coil are 10°C db-temperature and 90% relative humidity. The pressure is constant at 101.325 kPa. About 30% of the return air is replaced with outdoor air at 30°C db-temperature and 80% RH. Determine: The db-temperature of supply air in % The dry-air mass flow rate of supply air in kg/sarrow_forwardMoist air at 32 degrees Cdb and relative humidity of 60% enter a refrigeration system with a flow rate of 90 kg/min. Saturated air at 15 degrees Cdb leaves the system. Calculate the heat and moisture removed in kW and kg/s respectively.arrow_forwardwhich of the following properties is NOT true about moist air at standard condition which is at a dry bulb temperature of 340C and humidity ratio of 10g w/kg da ? 1. the relative humidity of the air is about 30% 2. The enthalpy of the air is about 55kj/kg 3.The specific volume of the air is about 0.884 m3/kg 4.The dew point temperature of the air is about 140Carrow_forward
- room contains air at 30 degrees * C and a total pressure of 96.0 kPa with a relative humidity of 75 percen ermine (a) the partial pressure of dry air and (b) the specific humidity.arrow_forwardAn air conditioning system, shown schematically below, supplies air at the rate of 4 kg/s to a space maintained at a db-temperature of 27°C and relative humidity of 50%. The sensible and latent heat loads on the space are 46 kW and 20 kW respectively. Outdoor air at 35°C db-temperature and 24°C wb-temperature is introduced at the rate of 1.1 kg/s. The relative humidity of the air leaving the cooling coil is 90%. The pressure is constant at 101.3 kPa. Determine:the supply air temperature in °Cthe supply air relative humidity in %the mass flow rate of the air that bypasses the cooling coil in kg/sthe refrigeration capacity of the cooling coil in kWarrow_forward2. An air-conditioning system is to take in outdoor air at 10 C and 30 percent relative humidity at a steady rate of 45 m3/min and to condition it to 25 C and 60 percent relative humidity. The outdoor air is first heated to 22 C in the heating section and then humidified by the injection of hot steam in the humidifying section. Assuming the entire process takes place at a pressure of 100 kPa, determine (a) the rate of heat supply in the heating section and (b) the mass flow rate of the steam required in the humidifying section. 22 C 25 C Heating Hum hiner 7,10°C. 7-25 C = 30%arrow_forward
- The temperature of the air in a dryer is maintained constant by the use of steam coils within the dryer. The product enters the dryer at the rate of one metric ton per hour. The initial moisture content is 3 kg moisture per kg of dry solid and will be dried to moisture content of 0.10 kg moisture per kg of dry solid. Air enters the dryer with a humidity ratio of 0.016 kg moisture per kg of dry air and leaves with a relative humidity of 100% while the temperature remains constant at 60°C. If the total pressure of the air is 101.325 kPaa, determine the vapor pressure at heater inlet in psia.arrow_forwardThe temperature of the air in a dryer is maintained constant by the use of steam coils within the dryer. The product enters the dryer at the rate of one metric ton per hour. The initial moisture content is 3 kg moisture per kg of dry solid and will be dried to moisture content of 0.10 kg moisture per kg of dry solid. Air enters the dryer with a humidity ratio of 0.016 kg moisture per kg of dry air and leaves with a relative humidity of 100% while the temperature remains constant at 60°C. If the total pressure of the air is 101.325 kPaa, determine the specific enthalpy at dryer outlet in kJ/kg.arrow_forwardIn an air-conditioning unit 3.5 m3/s of air at 32 C dry-bulb temperature, 50 percentrelative humidity, and standard atmospheric pressure enters the unit. The leavingcondition of the air is 18 C dry-bulb temperature and 90 percent relative humdity.Using properties from the psychrometric chart, (a) calculate the refrigeratingcapacity in kilowatts and (b) determine the rate of water removal from the airarrow_forward
- Fresh atmospheric air mixed with recycled air is heated to 349K and admitted to a drier at 101.3 KPa at a rate of 100 m3/min. The relative humidity of the air entering the drier is 7.5%. Atmospheric air is at 302K and has a relative humidity of 30%. The air leaves the drier at 306K and 90% relative humidity, a portion of which is recycled and the other portion discarded. The vapour pressures of water are 4KPa at 302K, 5KPa at 306K and 40KPa at 349K. Calculate the following:a) The ratio of wet recycle stream to wet fresh stream.b) The mass of dry air to be fed to the drier to remove one kilogram of water in the drier.c) The rate at which water is removed in kg/min.arrow_forwardThe dry bulb and wet bulb temperature of an enclosed room was 27 deg C and 23 deg C, respectively. Determine the following: Dew point temperature (in deg F) Enthalpy (BTU/lb) Specific volume (m^3/kg) Relative Humidity Humidity Ratio (lb air/ lb dg)arrow_forwardA sample of outdoor air (Point 1) has a dry- bulb and dewpoint temperature of 32°C and 24°C, respectively. It is mixed with another air (Point 2) with 50% relative humidity and a specific humidity of 0.0078 kgy/kga. If the mass of outdoor air (m1) amounts to 40% of the mixed air ( m3 ), determine: 1. Specific humidity at point 1 in kgy/kga- 2. Enthalpy at point 1 in kJ/kg. 3. Relative humidity at point 1 in %. 4. Dry-bulb temperature at point 2 in °C. 5. Enthalpy at point 2 in kJ/kg. 6. Specific volume of air at point 2 in m3/kg. 7. Dry-bulb temperature of the mixture (point 3) in °C. 8. Specific humidity of the mixture (point 3) in kgy/kga- 9. Enthalpy of the mixture (point 3) in kJ/kg. 10. Dewpoint temperature of the mixture (point 3) in °C.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