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Flashcards

HVAC

amsond01 English 62 cards

Cards in this deck (62)

  1. 1What is the composition of Dry AirOxygen 21%
    Nitrogen 78%
    Argon 1%
  2. 2Define Sensible heatingheat added to air-water mixture and causes a temperature change
  3. 3Define Latent heatingheat added to the substance that causes it to go through a phase change
  4. 4What is the bypass factorfraction of air that does not come into contact with the cooling coil
  5. 5What is a Hygrometerhumidity sensor
  6. 6Name types of humidity sensorsSling Psychrometer
    Mechanical System (horse hair)
    Electrical Systems (capacitance or resistance varies)
  7. 7On Psych Chart the Sensible heat moves (blank) and the latent heat moves (blank)Sensible - Left to right
    Latent - Top to Bottom
  8. 8What are the Four Parameters that affect Human ComfortDry Bulb
    Humidity
    Temp. of Surroundings (Radiation)
    Air Velocity (Convection)
  9. 9What are 2 Parameters of human comfort that can be controlledClothing
    Activity Level
  10. 10What is the fraction of heat loss from the body that is sensible40% for Heavy Work
    70% for Light Work
  11. 11Studies show that people spend (blank) percent of their time indoors90
  12. 12ASHRAE 62.1 is the standard for...ventilation for acceptable indoor air quality
  13. 13ASHRAE 62.1 defines indoor quality of air in which no known contaminants harmful concentrations as determined by cognizant authorities for which (blank) percentage of people are not dissatisfied80%
  14. 14What is the CO2 Limit1.8 g/m3
    or
    1000ppm
  15. 15Name some methods to control indoor contaminants1. Dilution (use OA)
    2. Source Removal
    3. Fume Hoods
    4. Air Filtering/Cleaning
  16. 16What is difference between old and new ventilation calculatingOld - ventilation per person
    New - ventilation per person and square footage
    (new is generally lower)
  17. 17Gas removal can be accomplished by the following processes1. Absorption
    2. Adsorption
    3. Chemiosorption
    4. Catalysis
    5. Combustion
  18. 18Various ways or particulate removal are1. Filtering - straining, interception, diffusion
    2. Electrostatic Precipation
  19. 19MERV stands forMinimum Efficiency Reporting Value
  20. 20ERVs are in (blank) percentage of buildings but in (blank) percentage of all high performance buildings3
    43
  21. 21Name some health related IAQ issues1. Molds
    2. Second Hand Smoke
    3. Legionella
    4. SARS
    5. VOCs
    6. Radon
  22. 22What are the lifecycle building costs conpared to people1. 25% energy, Initial Construction, Taxes, and Maintenance
    2. 96% Salaries, 4% of above
  23. 23Human body generates approx. (blank) Btu/hr400
  24. 24Skin Temp is approximately (blank) F91.5-93
  25. 251 MET is equal to...18.4 Btu/hr ft2
    58.2 W/m2
  26. 261 clo is equal to (blank) F ft2/Btu or (blank) m2C/W0.88
    or
    0.155
  27. 27What is the Maximum concentration for CO2? Ozone?CO2 - 700ppm above outdoor
    Ozone - 0.05 ppm
  28. 28Small particles have (blank) settling velocities and large (blank) in airsmall
    diffusion coeffiecents
  29. 29Name applications for high/low MERV ratingsLow Rating: (1-4) Residential, panel filters
    High Rating: (17-20) High risk surgery, clean rooms, HEPA filters
  30. 30What are the solar Irradiation wavelength spectrum0.4-3 micro meters
  31. 31What is the max declination and when does it occur23.5 and Summer Solstice or Winter Solstice
  32. 32Zenith angle is angle between what and whatNormal of earth's surface and suns ray
  33. 33azimuth angle is between what and whatSouth and suns rays
  34. 34What happens to the solar altitude angle as it gets closer to summer solsticegets larger
  35. 35what are the following angles theta p azimuth of surface incidence anglethetap=beta=tilt of surface
    azimuth of surface=angle from south to normal of suns rays
    incidence angle=angle between normal and sun ray
  36. 36What are typical reflection coefficients for grass or concretegrass = 0.24
    concrete = 0.34
  37. 37standard h values for inside, outside winter and outside summer (btu/hrft2F)inside=1.46
    outside,winter=6
    outside,summer=4
  38. 38When solving for U of windows what are neededcenter of glass, edge of glass, and frame of window
  39. 39What are typical U valuse of Windows0.5(good)-0.15(high) btu/hrft2F
  40. 40describe/draw distribution of solar radiation on clear glass80%Transmitted
    4% Flow of absorbed
    8% reflected
    8% out flow of absorbed
  41. 41The better the window the (larger or smaller) the SHGCsmaller
  42. 42U factor gets (larger/smaller) with better windowslarger
  43. 43For design conditions the rule of thumb is to use the (blank)% Tdb for summer and (blank)% Tdb for winter1%
    99%
  44. 44what makes up ktotUAglaze
    UAwall
    UAroof
    infiltration
  45. 45Common methods for calculating cooling loadsHeat Balance Method
    Transfer Functions for Dynamic Loads
    CLTD/CLF/SCL Method
    Radiant Time Series
  46. 46What did Monicello Wall problem showWall temp would increase drastically while center of wall and inner wall stayed constant
  47. 47what kinds of components have a radiative component with a convective time delayFurnishings, things with thermal mass
  48. 48What two methods help find Annual Energy ConsumptionDegree Day and Bin Method
  49. 49Why is elevator heat loss a problemthe negative pressure in the elevator shaft is causing the warm air into the shafts decreasing efficiency and increase costs
  50. 50When designing a building you want slightly negative or positiveslightly positive
  51. 51The total energy through a window is made up of what three thingsradiation transmitted, inward flow of absorbed radiation, conduction through window
  52. 52What assumptions are made for sol air temp1. Same emissivity
    2.radiation exchange is linearized
    3.all surroundings same temp
    4.correction is added for surfaces that see the sky
  53. 53three things that fill window gapcrypton, argon, air
  54. 54What is KCR methodGives the maximum solar heat gain value
  55. 55What is MCWBMean Coefficient Wet bulb (temp that occurs above 95F)
  56. 56What is mean daily rangetemperature variation for a summer day (Louisville=23F)
  57. 57Name three things that are negligible in DD method1. Variation in internal heat gains
    2.variation in solar heat gains
    3.thermal storage effects
  58. 58When does balance point occurLosses equal gains
  59. 59What is needed to calculated HDD or CDD1. Days in month
    2. Avg monthly temp.
    3.Base temp
    4. Standard deviation of temp
  60. 60older buildings have ACH of (blank) current buildings have ACH of (blank) Buildings in Sweden have ACH of (blank)1-2
    0.3-0.7
    0.1
  61. 61what are three methods of infiltration1. ACH method
    2. LBL method
    3. Pressure change method
  62. 62On psych. chart: 1. Up 2. Up and Left 3. Left 4. Down Left 5.Down 6. Down Right 7.Right 8. Up Right1. Humidification, 2. Cooling/Humidification, 3. Sensible Cooling, 4.Cooling/De-humidification, 5. De-humidification, 6. Heating De-humidification 7. Sensible Heating, 8.Heating/Humidifying

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Test 2
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amsond01
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