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Definition
| Treating air so as to control simultaneously its temperature, humidity, cleanliness, and distribution to meet requirements of the conditioned space. |
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| streams or currents of air rapid enough to cause discomfort. |
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Definition
| Transfers room heat from return air to water. Also cools outside air in summer. |
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| Transfers heat from water to supply air |
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| Transfers heat of flame to water |
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Definition
| Transfers heat to room in winter; heat transferred from room in summer. |
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Definition
| Transfers unwanted room heat and compressor work heat from condenser cooling water to outside air. |
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Definition
| Transfers unwanted room heat from water to refrigerant vapor. |
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Definition
| Pumps refrigerant vapor from evaporator to condenser. |
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Definition
| Transfers unwanted room heat and compressor work heat from refrigerant to condenser cooling water. |
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| One BTU equals ___ calories. |
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Definition
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Definition
| The boiling point of a substance |
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Definition
| The latent heat of fusion of water |
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Term
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Definition
| The latent heat of vaporization of water |
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Term
| When pumping water, the flow rate is usually measured in... |
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Definition
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| Air quantities are measured by... |
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Definition
| Cubic feet per minutes (CFM) |
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Definition
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| The actual value of atmospheric pressure at a specific location and time |
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Definition
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Definition
| Pressure existing above a perfect vacuum, or 30 inches Hg. |
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Definition
| The specific branch of knowledge on which the theory and practice of air conditioning is based. |
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Term
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Definition
| Air as it exists in the normal atmosphere. Primarily as mixture of oxygen and nitrogen. |
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Term
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Definition
| Atmospheric air from which all water vapor and contaminants have been removed. |
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Term
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Definition
| The type of air with which air conditioning is concerned. A mixture of dry air and water vapor. |
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Term
| 1/0.075, or 13.33 cubic feet |
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Definition
| Volume occupied by one pound of standard air. |
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Definition
| The temperature indicated by an ordinary thermometer. |
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Term
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Definition
| The temperature registered by a thermometer whose bulb is covered by a wick that is wetted with water and exposed to a current of moving air. |
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Term
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Definition
| The difference between the dry-bulb and wet-bulb thermometer. Useful in determining the relative humidity. |
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Definition
| The total amount of heat in the air. |
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Term
| Wet-bulb temperature is a measure of... |
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Definition
| both sensible and latent heat. |
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Term
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Definition
| The temperature where the air will be saturated with the maximum amount of water vapor. A true indication of the amount of moisture in the air. |
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Term
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Definition
| Moisture of water vapor present in the air in a given space. |
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Definition
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Definition
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Definition
| A figure giving the weight of water vapor per unit volume of air. |
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Definition
| The ratio of the amount of moisture actually present in the air as compared to the amount of moisture the air would hold at the same dry-bulb temperature, if it was saturated. Usually given as a percentage. |
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Term
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Definition
| The ability to attract and absorb moisture. |
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Term
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Definition
| Heat exchange when objects or bodies are in direct physical contact with one another, depending on the thickness of the objects. |
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Term
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Definition
| A combination of heat transfer by conduction together with transfer by actual movement of some of the fluid from one place to another, resulting in a mixing or diffusing action. |
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Term
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Definition
| Due to gravity, the less dense, or lighter air will rise. |
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Term
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Definition
| Heat exchange that takes place through space to objects in the path of waves or rays. |
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Term
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Definition
| Fluid particles flow along smooth and at low velocities. |
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Term
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Definition
| Increased velocity of liquids, creating eddies and swirls, which makes for a more efficient transfer of heat. |
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Definition
| The heat transfer surface of the solid which also acts as the surface to retain the fluid, and against which the fluid flows. An example being bare-pipe coil. |
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Term
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Definition
| Heat transfer can be increased by attaching fins. |
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Term
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Definition
| Tubes that have internal grooved cut into them similar to rifling. |
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Definition
| Gives a higher average temperature difference than parallel flow. |
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Definition
| The rate given to materials at which heat will flow through it. |
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Term
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Definition
| The ability to transmit heat by conduction. |
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Term
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Definition
| Thermal conductivity where building materials are assumed to be uniform. |
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Term
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Definition
| Thermal conductivity where building materials are not uniform. |
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Term
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Definition
| Film conductance/coefficient. Heat flow between air and the surface of an object. |
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Term
| Wind velocity in the winter |
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Definition
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Term
| Wind velocity in the summer |
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Definition
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Term
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Definition
| 6.00 for 15 mph winds/ 4.00 for 7.5 mph winds. |
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Term
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Definition
| Most popular wall construction, ranging from 1.46-1.63. |
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Term
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Definition
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Term
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Definition
| Thermal resistance. The reciprocal of the heat transfer coefficient. |
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Term
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Definition
| The leakage of outdoor air into buildings. |
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Definition
| Conditioned air brought in from an Air handler. |
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Term
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Definition
| The process of air leaving the building. |
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Term
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Definition
Involves the linear length of cracks around walls, doors, and windows. Not very accurate.
Best for homes and office buildings. |
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Term
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Definition
| Based of the room volume of the conditioned spaces, with no care about wind or thermal pressure. Best in large commercial settings. |
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Term
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Definition
| Prevents or reduces the escape of water vapor through walls. Installed on the warm side of the insulation. |
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Term
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Definition
| The body is able to maintain a satisfactory rate of heat removal. 75 degrees F at 50% RH. |
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Definition
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Definition
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Definition
| The overall temperature of surrounding surfaces. |
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Definition
| An arbitrary temperature, used to indicate the combined effect of temperature and humidity on human comfort. |
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Term
| The desirable range of air velocities |
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Definition
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Term
| Saturated air is so called because it has |
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Definition
| A given temperature and pressure |
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Term
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Definition
| The process of causing heat to flow from one place to another. |
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Term
| A complete air conditioning system treats air by 6 processes: |
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Definition
| heating, cooling, dehumidification, humidification, cleaning, distribution. |
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Term
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Definition
| The weight of water per pound of dry air. |
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Term
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Definition
| Instruments for measuring and indicating or recording relative humidity. |
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Term
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Definition
| A thin layer that tends to reduce the rate of heat flow |
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Term
| High velocity ___ the effect on the boundary layer |
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Definition
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Term
| Dark surfaces ___ heat and ___ the U-factor. |
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Definition
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Term
| Two general ways in which the human body transfers heat to its surroundings: |
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Definition
| Dry heat exchange and evaporative heat loss. |
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Term
| Heat transfer occurs because |
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Definition
| of a difference in temperature. |
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Term
| Chimney effect/Stack effect |
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Definition
| Infiltration caused by an outdoor/outdoor temperature difference and corresponding density difference. |
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Term
| Two reasons for supplying ventilation air: |
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Definition
| Odors and to control pressure. |
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Term
| Two considerations that govern the amount of ventilation air supplied: |
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Definition
| Type of occupancy and local codes. |
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