![Heating Ventilating and Air Conditioning: Analysis and Design](https://www.bartleby.com/isbn_cover_images/9780471470151/9780471470151_largeCoverImage.gif)
An interior zone of a large building is designed to have a supply air-flow rate of 5000 cfm (2.4 m3/s). The cooling load is constant at 10 tons (35 kW) with a SHF of 0.8 year-round. Indoor conditions are 75 F (24 C) db and 50 percent relative humidity (RH). (a) What is the maximum air dry bulb temperature and humidity ratio that would satisfy the load condition using all outdoor air? (b) Consider a different time when the outdoor air has a temperature of 40 F (4 C) db and 20 percent relative humidity. Return air and outdoor air may be mixed to cool the space. but humidification ill be required. Assume that saturated water vapor at 14.7 psia (101 kPa) is used to humidify the mixed air, and compute the amounts of outdoor and return air in cfm (m3/s). (c) At another time, outdoor air is at 65 F (18 C) db with a relative humidity of 90 percent. The cooling coil is estimated to have a minimum apparatus dew point of 45 F (7.2 C). What amount of outdoor and return air should be mixed before entering the coil to satisfy the given load condition? (d) What is the refrigeration load for the coil of part (c) above?
![Check Mark](/static/check-mark.png)
Want to see the full answer?
Check out a sample textbook solution![Blurred answer](/static/blurred-answer.jpg)
Chapter 3 Solutions
Heating Ventilating and Air Conditioning: Analysis and Design
Additional Engineering Textbook Solutions
Automotive Technology: Principles, Diagnosis, and Service (5th Edition)
Applied Fluid Mechanics (7th Edition)
Manufacturing Engineering & Technology
INTERNATIONAL EDITION---Engineering Mechanics: Statics, 14th edition (SI unit)
Fundamentals Of Thermodynamics
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
- In a place where a summer air-conditioning plant will be installed, 40% of the air entering the air-conditioning plant is the fresh air, and 60% is the return (bypass) air. The sensible heat gain of the place is 10 kW. and the latent heat gain is 2.5 kW.> Outdoor conditions: 32 °C DB, %50 RH.> Indoor conditions: 20 °C DB. %50 RH.> Take the relative humidity of the air passing through the cooling coil 90% at the coil outlet. > The total air flow rate in the mixing chamber is 3000 m3/h> Take the density of the air as 1.2 kg/m3Based on the above. Calculate the amount of fresh air. What is the value of enthalpy of blowing air. Calculate the ratio of by-pass air at cooling coil. Calculate the flow rate of by-passed air.arrow_forwardIn a place where a summer air-conditioning plant will be installed, 40% of the air entering the air-conditioning plant is the fresh air, and 60% is the return (bypass) air. The sensible heat gain of the place is 10 kW. and the latent heat gain is 2.5 kW.> Outdoor conditions: 32 °C DB, %50 RH.> Indoor conditions: 20 °C DB. %50 RH.> Take the relative humidity of the air passing through the cooling coil 90% at the coil outlet. > The total air flow rate in the mixing chamber is 3000 m3/h> Take the density of the air as 1.2 kg/m3Based on the above.a) Show the process on a psychrometric diagram. b) Calculate the amount of fresh air. c) What is the value of enthalpy of blowing air. d) Calculate the ratio of by-pass air at cooling coil. e) Calculate the flow rate of by-passed air.arrow_forwardASHRAE standard 55, Thermal Environmental Conditions for Human Occupancy, notes that for thermal comfort purposes, the indoor temperature should range from approximately 67ºF to 82°F (19.4ºC to 27.8ºC), and systems designed to control humidity must be able to maintain a dew-point temperature of 16.8°C (62.2°F). ASHRAE standard 62.1, Ventilation and Acceptable Indoor Air Quality, recommends that relative humidity in occupied spaces be controlled to less than 65% to reduce the likelihood of conditions that can lead to microbial growth. Determine the minimum allowable indoor temperature that will ensure a humidity control system designed according to ASHRAE standard 55 will also satisfy the humidity requirements of standard 62.1arrow_forward
- Example 1.12 Air at a dbt (dry bulb temprature) of 30 °C and a relative humidity of 30% is conveyed through a heated dryer where it is heated to a dbt of 80 °C. Then it is conveyed through a bed of granular pet food to dry it. The air exits the dryer at a dbt of 60 °C. The exit air is again heated to 80 °C and conveyed through another dryer containing another batch of pet food. The exit air from the second dryer leave at saturation. Clearly show the paths of air, starting from the ambient air to the saturated air exiting the second dryer on a copy of a psychrometric chart Determine the amount of water removed in the first and second dryer per kg of dry air.arrow_forwardExplain where did 23.4 came fromarrow_forward1. Plot the four locations in the psychrometric chart and determine the other properties foreach condition using a psychrometric chart (Appendix 8a and 8b). Locations of air Tdb, °C Twb, °C Ambient air 32 28 Conditioned air 25 20 Air at the dryer inlet 30 23 Air at the dryer outlet 33 27 3. What is the relationship between relative humidity and temperature? What about humidityratio and temperature?arrow_forward
- Using a psychometric diagram, describe the heating and humidification process from the following data. Initially the air was at dry bulb temperature (DBT) 35 ° C and RH 35%. air preheated to DBT 85 ° C. The heated air is then flowed through a humidifier to increase the RH to 25%. for this process, count, a. change in absolute humidity of air from initial to final conditions = ..... (kg water / kg air) b. change in air enthalpy from initial to final conditions = ..... (kj / kg air)arrow_forwardAtmospheric air with an air flow rate of 200 liter/min and a dry bulb temperature of 35 °C and relative humidity of 40 % is cooled to 10 °C using an air conditioner. Determine: a) How much water per hour is removed from the air during the process; b) The cooling capacity of the air conditioner required to cool the air.arrow_forward2.) Moist air at 32∘Cdb and relative humidity of 60% enter a refrigeration system with a flow rate of 90 kg/min. Saturated air at 15∘Cdb leaves the system. Calculate: (a) the heat removed, in kW (b) moisture removed, in kg/sarrow_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
![Text book image](https://www.bartleby.com/isbn_cover_images/9780190698614/9780190698614_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9780134319650/9780134319650_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781259822674/9781259822674_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781118170519/9781118170519_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781337093347/9781337093347_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9781118807330/9781118807330_smallCoverImage.gif)