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25 Cards in this Set
- Front
- Back
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HVAC |
Heating Ventilating and Air Conditioning |
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What do carbon or charcoal filters eliminate? |
Odor or gases |
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What does HEPA filter stand for and where is it used? |
High Efficiency Particulate Air, used in contamination free zone IE hospital, computer chip. |
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Humidifying |
Adding moisture to air |
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Dehumidifying |
Removing moisture from air |
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What does air do when heated? |
Expands |
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What is air made up of? |
78% nitrogen, 21% oxygen, 1% misc. Gas |
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Standard air temp @ sea level |
Dry air at 70 deg. F and barometric pressure of 29.92" Hg. |
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How much does 1 cubic foot of air equal? |
.075 Lbs. |
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Which holds more water vapor, hot or cold air ? |
Hot |
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How does a sling psychrometer work? |
Whirled by hand to make air pass over wet wick |
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Psychrometer measure both....? |
Wet and dry bulb |
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Evaporation does what to air? |
Cools it |
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Process of ventilation |
Supplying or removing air by natural or mechanical means |
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Difference in pressure causes air to...? |
Move |
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What does K value measure? |
How well material conducts heat IE insulation |
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How efficient is electric heat? |
100% |
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What is BTU heat measured off of? |
Heat of striking a wooden match & amount of heat req. to raise 1lb or water 1 deg. |
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How many BTUs in a Ton? |
12,000 BTUs |
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What is sensible heat and what measures it? |
Heat we can feel or sense measured with dry bulb thermometer |
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What is Latent heat ? |
Heat released or absorbed by a change of state |
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What is refrigeration based off of ? |
Liquid under pressure boils at higher heat then under low pressure |
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What causes friction loss ? |
Air hitting sides of duct |
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What causes dynamic loss ? |
Change in air flow |
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3 main devices of measurement |
Sling psychrometer, manometer, anamometer |
