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 and Air Conditioning: Analysis and Design
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 space is to be maintained at 75 F db and 40% relative humidity. The total heat gain to the space is 62,000 Btu/hr with a SHF of 0.8. The outdoor air requirement is 500 cfm. The outdoor air has a temperature of 90 F and 50% relative humidity. Assume that the supply air has a temperature of 50 F db. Determine the following: a. Quantity of supplied air b. Capacity of the cooling coil c. Rate of moisture removal from the dehumidification elementarrow_forwardThe cooling load of a building is estimated at 60 000 Btu/hr, of which 25 % is latent heat. The space is to be maintained at 75 F db and S0 % relative humidity. The outdoor air is at 110 F db and 40 % relative humidity. The air is supplied to the space at 55 F. If the sensible heat factor of the cooling equipment is SHF-0.6 and by using the psychrometric chart The supplied air mass tlow rate is around Choose The outside mass flow rate is around Choose. The cooling coil total heat rate is around Choose The sensible heat rate of the cooling coil is around Choose The latent heat rate of the cooling coil is around: Choosearrow_forwardA 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_forward
- An air-conditioning system operates at a total pressure of 1 atm and consists of a heating section and a humidifier that supplies wet steam (saturated water vapor) at 100 degrees celsius. Air enters the heating section at 10 degrees celsius and 70 percent relative humidity at a rate of 35 m^3/min, and it leaves the humidifying section at 20 degree celcius and 60 percent relative humidity. Heating coils Loooooooo 10°C 70% 35 m³/min AIR P = 1 atm Sat. vapor 100°C Humidifier € 20°C 60% a. Humidity ratio at inlet b. Relative humidity at the exit c. Humidity ratio at exit d. Rate at which water is added to humidifying sectionarrow_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_forwardP=19 Moist air goes into air-conditioning unit at a degree-30 C and 70% relative humidity, and it is cooled to 20-degree C and 20% relative humidity at a constant pressure of 1.01325 bar. The mass flow rate of dry air is mda=63 kg/s The unit applies refrigerant R-134a as the cooling fluid that enters inside the tubes of the cooling coil at 3.6 bar with a quality of 0.2 and leaves as a saturated vapor at the same pressure of 3.6 bar. Use the psychometric chart to determine: a) Mass flow rate of condensed water in kg/s b) The heat transfer rate from the air to the cooling coil in kW (Use the psychometric chart) c) The mass flow rate of R-134a that is needed in kg/sarrow_forward
- which 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_forwardi was trying to understand and studying thermodynamics course but this example had seen pretty hard to me. thanks to the person who can explain the solution of that example to me.arrow_forwardIn an air conditioning system 30 cmm of fresh out door air is introduced at 43°C Dbt and 30% RH. The remaining air is recirculated from the room maintained at 25°C DBT and 50% RH. The bypass factor of cooling coll is 0.15 and apparatus dew point is 11.8°C, RSH = 100 kW and RLH= 15 kW. Determine: (1) Humidity ratios for outdoor and Room conditions. (Ii) OASH & OALH (iii) ERSH and ERLHarrow_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_forwardPlease answer in clear handwritingarrow_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