Air conditioning and heat pump Flashcards
(128 cards)
1
Q
How much tonnage do you need in southern us
A
450-700 sq ft per ton
2
Q
How much tonnage do you need in northern us
A
700-1000 sq ft per ton. 8 ft ceilings
3
Q
What is the standard temperature difference (ΔT) between supply and return air in a properly functioning A/C system?
A
14–22°F.
4
Q
What type of refrigerant is commonly used in newer HVAC systems?
A
R-410A (replaces R-22, which is being phased out).
5
Q
What is the purpose of a heat exchanger in a furnace?
A
To transfer heat from combustion gases to air without mixing the two.
6
Q
: What is a common cause of short cycling in an HVAC system?
A
Dirty air filter, oversized unit, or thermostat issues.
7
Q
A
8
Q
When will la heat exchanger furnace oxidize faster?
A
When connected to an air-conditioning unit
9
Q
When should a gas furnace piolet light be turned off?
A
In the summer
10
Q
In a Complete Heat system, many local codes require the maximum water temperature to be?
A
120 degrees F.
11
Q
What on an air conditioner provides for heat transfer from high temperatures to low temperatures?
A
Condenser coil fins
12
Q
On an AC system, which coil is the indoor coil?
A
Evaporator coil
13
Q
What does EER apply to regarding air conditioners?
A
Energy efficiency ratio
14
Q
Evaporative coolers require?
A
A low relative humidity
15
Q
Ground loop consists of what pipe?
A
Polyethylene
16
Q
A swamp cooler is another name for?
A
Evaporative coolers
17
Q
Evaporative coolers are found where?
A
West and Southwest region of the U.S.
18
Q
Evaporative coolers?
A
Cool air through the evaporation of water
19
Q
Absolute humidity
A
Amount of moisture in the air, indicated in grains per cu. ft.
20
Q
Absolute temperature
A
Temperature measured from zero
21
Q
Activated charcoal
A
Highly absorbent charcoal that is free of contamination
22
Q
Active system
A
Solar heating system using mechanical means of heat collection, storage, and distribution
23
Q
AGA
A
American Gas Association
24
Q
Air ducts
A
Pipes that carry warm and cold air to rooms and return back to the heating or cooling system
25
Air-heating collector
Solar collector, such as a thermosiphoning air panel (TAP) or window box collector, designed to absorb solar energy, convert it to heat and transfer the heat, to air flowing from the house, through the collector, and back to the house.
26
Air return
Air that returns from conditioned or refrigerated space to the source
27
Alpha particle
Energized particle made up of two protons and two neutrons that is ejected from a radioactive atom.
28
Annual fuel utilization efficiency (AFUE)
Rating that measures the average annual seasonal efficiency of a boiler or furnace by measuring the heat produced from a given amount of fuel.
29
Anticipating control
One that is artificially forced to cut in or out before it originally would, thus starting cooling before needed or stopping heating before the control point is reached. It reduces the temperature fluctuation or override.
30
Ash dump
Trap door that allows ashes to drop to a pit below for removal.
31
Background radiation
Average radiation from all sources found in the surroundings.
32
Balance point
Where the heat pump capacity exactly matches the heating loss.
33
Balancing damper
Baffle or plate used to control the volume of flowing air in a confined area.
34
Blower
Fan used to force air under pressure.
35
Boiler
At high pressure (steam), furnishing pressure at 15 psi or more; at low pressure (hot water) furnishing steam at a pressure less than 15 psi or hot water at not more than 30 psi.
36
British thermal unit (Btu)
Heat energy required to raise the temperature of 1 lb of water 1 degree F.
37
Btuh
Btus per hour
38
Burner
Domestic heating boilers are generally low pressure with maximum working pressure of 15 psi for steam and 30 psi for hot water.
39
Central heating system
Boiler or furnace flue connected and installed as an integral part of the structure and designed to supply heat adequately for the entire structure.
40
cfm
Cubic feet per minute
41
Charge
The amount of refrigerant in a system.
42
Chimney
Vertical masonry shaft of reinforced concrete or other approved noncombustible heat-resisting material enclosing one or more flues. the chimney removes the products of combustion from solid, liquid, or gaseous fuel.
43
Chimney breast
Inside face or front of the fireplace chimney.
44
Chimney cap
Protects chimney brick from weather. The chimney cap is generally made from concrete.
45
Chimney connector
Pipe or breaching that connects a heating unit (such as a fuel-burning appliance) to the chimney.
46
Chimney effect
Tendency of air or gas in a duct or another passage to rise when heated, due to its lower density caused by a difference in temperature. typically, the air is replaced by cooler, denser air flowing in through lower level openings.
47
Choke tube
Throttling device used to maintain correct pressure between the high and low side in the refrigerating mechanism; sometimes referred to as capillary tube.
48
Cleanout door
Door to ash pit at the bottom of a chimney.
49
Clearance
Distance separating the appliance, chimney connector, plenum, and flue from the nearest surface of combustible material.
50
Coefficient of performance (COP)
Ratio of work or energy applied compared with energy used.
51
Coil
Any heating or cooling element made of pipe or tubing connected in series.
52
Coil blower
Consists of a metal cabinet, a filter, a blower, an air-conditioning coil, and electric controls. Blower coils are used for air-conditioning only, even though electric heat is available.
53
Collection
Act of trapping solar radiation and converting it to heat.
54
Combustion
Rapid oxidation accompanied by heat and light; a process of burning.
55
Compressor
Pump of a refrigerating mechanism that draws a vacuum or low pressure on the cooling side of the refrigeration cycle and compresses the gas into the high-pressure or condensing side of the cycle.
56
Condensate
Water extracted from air by the evaporator coil during the cooling cycle. Also refers to the pump device used to remove moisture that collects under the coils.
57
Condenser
Part of the refrigeration mechanism that receives hot, high-pressure refrigerant gas from the compressor and cools gaseous refrigerant until it returns to the liquid state.
58
Condenser comb
Comb device made of metal or plastic that is used to straighten the metal cooling fins on the condensers and/or the evaporator coils.
59
Condensing unit
That part of the refrigerating mechanism that pumps vaporized refrigerant from the evaporator, compresses it, liquefies it in the condenser, and returns the liquid refrigerant to the refrigerant control.
60
Conduction
Passage of heat energy through a material by molecular excitation.
61
Control, combustion safety
Primary safety control that responds to flame properties, sensing the presence of flames an causing the fuel to shut off in the event of flame failure.
62
Convection
Heat transfer in air, water, or another fluid by currents resulting from the medium's falling when cooler and heavier and rising when warmer and lighter.
63
Convection heat
Transfer of heat by means of movement or flow of a fluid or gas.
64
Convector
Radiator that supplies a maximum amount of heat by convection, using many closely spaced metal fins fitted onto pipes that carry hot water or steam, thereby heating the circulating air.
65
Conversion
Boiler or furnace originally designed for solid fuel but converted to use liquid or gaseous fuel.
66
Cooling season
Portion of the year when outdoor heat makes indoor cooling desirable.
67
Cut-in point
The temperature at which the thermostat calls for system operation.
68
Cut-out point
The temperature at which the thermostat stops calling for heating or cooling.
69
Cycle rate
The number of times per hour that the heating or cooling equipment is cycled on at half-load conditions.
70
Differential (As applied to HVAC)
The difference between cut-in and cut-out temperature or pressure control.
71
Direct gain system
Passive solar heating system in which sunlight penetrates and warms the house interior directly.
72
Direct radiation
Radiation that comes directly from the sun, without being reflected of diffused.
73
Distribution
The act of moving heat energy from the point of collection or storage to the point of use.
74
Draft
Usually refers to the pressure difference that causes a current of air or gases to flow through a flue, chimney, heater, or space.
75
Draft gauge
Instrument used to measure air movement.
76
Draft hood
Device placed in and made part of the vent connector from the appliance or in the appliance itself that is designed to 1. ensure the ready escape of the products of combustion in the event of no draft , backdraft, or stoppage beyond the draft hoods; 2. neutralize the effect of stack action of the chimney flue on appliance operation.
77
Draft indicator
Instrument used to indicate or measure chimney draft or combustion gas movement. Draft is measured in units of 0.1" of water column.
78
Draft regulator
Device that functions to maintain a desired draft in oil-fired appliances by automatically reducing the chimney draft to the desired value. It is also called a barometric damper and is referred to as an air balance, an air stat or a flue velocity control.
79
Drip pan
Pan-shaped panel or trough used to collect condensate from the evaporator coil.
80
Droop
An indoor temperature control condition where the room remains below the thermostat setting. This control occurs in mild cooling conditions and is caused by the cooling anticipator resistor, which provides a false heat source for the thermostat to maintain relative humidity control.
81
Dry bulb temperature
Air temperature as indicated by an ordinary thermometer.
82
Evaporative cooler
System in which the absorption of latent heat by evaporation of water cools the air it contacts.
83
Evaporator coil
Device made of a coil of tubing that functions as a refrigerant evaporator.
84
Flue liner
Fireclay tile not less than 5/8" thick that provides a smooth flow and protection from leakage.
85
Freon
Trade name for family of synthetic chemical refrigerants. It is a colorless gas.
86
Fuel oil
Liquid mixture derived from petroleum that does not emit a flammable vapor below 125 degrees F.
87
Heat, latent
Term used to describe the heat energy required to change the form of a substance without changing its temperature.
88
Heat, sensible
Term used in heating and cooling to indicate any portion of heat that change sonly the temperature of the substance involved.
89
Heat, total
Sum of latent and sensible heat.
90
Heat anticipator
A bias heater that shuts off the thermostat before the room reaches the thermostat setting; the heat anticipator minimizes overshoot.
91
Heat exchanger
Device used to transfer heat from a warm or hot surface to a cold or cooler surface.
92
Heating control
Controls temperature of a heat transfer unit that releases heat.
93
Heating plant
The furnace, boiler, or other heating device used to generate steam, hot water, or hot air, which is then circulated through a distribution system. It uses coal, gas, oil, wood or electricity as its source of heat.
94
Heating season
Portion of the year when outdoor cold makes indoor heating necessary.
95
Hermetic system
Refrigeration system that has a compressor driven by a motor contained in a compressor done or housing.
96
High efficiency
Term applied to heating and air-conditioning units that supply more heating or cooling for each energy dollar invested.
97
High side
Parts of a refrigerating system that are subject to under-condensing or high-side pressure.
98
HVAC
Heating, ventilation and air-conditioning
99
Hybrid system
Solar heating system that combines passive techniques with active devices such as fans or blowers t assist in the collection, storage, or distribution of heat.
100
Ignition transformer
Transformer designed to provide high voltage current; used in some heating systems to ignite fuel.
101
Indirect gain system
Solar heating system in which sunlight directly warms an absorber located between glazing and living space; heat is then distributed from the absorber to the living space naturally or by fans.
102
Liquid line
Carries liquid refrigerant from the condenser or liquid receiver to the refrigerant control mechanism.
103
Low-side pressure
Pressure in cooling side of the refrigerating cycle.
104
Low-side pressure control
Used to keep low-side evaporating pressure from dropping below a given pressure.
105
Manual or Mechanical differential
The difference (in degrees F) between cut-in and cut-out temperature with no electrical load connected to the thermostat.
106
Off cycle
Part of the refrigeration cycle; when the system is not operating.
107
Oil burner
Device for burning oil in heating appliances such as furnaces, boilers, water heaters, and ranges. A burner of this type can be a pressure-atomizing gun type, a horizontal or vertical rotatory type, or a mechanical or natural draft-vaporizing type.
108
One ton of cooling
Removal of heat from a conditioned space at the rate of 12,000 Btus per hour.
109
Operating differential
The difference (in degrees F) in cut-in and cut-out temperature when the thermostat is actually operating equipment. Operating differential is less than mechanical differential.
110
Passive system
A solar system using natural means to heat collection, storage and distribution.
111
Pressure drop
Pressure difference between the high side and the low side in a refrigerator mechanism.
112
Pressure regulator, evaporator
Automatic pressure-regulating valve, mounted in the suction line between the evaporator outlet and the compressor inlet to maintain a predetermined pressure and temperature in the evaporator.
113
Pressure suction
Pressure in the low-pressure side of a refrigerating system.
114
Radiant heat
Infrared energy that is emitted from the outer surfaces of a solid fuel-burning fireplace.
115
Radiant heating
Method of heating a building by means of electric coils, hot water, or steam pipes installed in the floor, walls or ceilings.
116
Radiation
Movement of energy through space by electromagnetic waves; i.e. the transfer of heat by heat rays.
117
Refrigerant
Substance circulated under pressure within a cooling system that produces the refrigerating effect.
118
Register grille
Covered opening in a floor or wall where hot or cold is introduced into a room.
119
Return air
Air delivered to the furnace to be treated.
120
Return air grille
Metal louvered grille over an opening to the return air plenum through which air enters the system for treating.
121
Sensible heat
Heat energy that changes the temperature of a substance without changing its state.
122
Set point
The temperature at which the thermostat indicator is set.
123
Short cycling
Continual starting and stopping of a system over a shorter than normal time period.
124
Split system
Air-conditioning installation that places the condensation unit outside or far from the evaporator.
125
Thermosiphoning air panel (TAP)
Air heating collector attached to the exterior of a south-facing house wall.
126
Thermostat
Temperature sensitive electrical circuit control that is responsive to the air temperature.
127
Vapor
Word used to denote vaporized refrigerant rather than the word gas?
128
Withe
1. Partition between two chimney flues in the same stack; 2. inner and outer walls of a cavity wall
