chapter 1 Flashcards
(ASHRAE)
American Society of Heating Refrigerating & Air conditioning Engineers
Define air conditioning as a process of treating air so as to control simultaneously
its temperature, humidity, cleanliness and distribution to meet the condition of a
given space.
(ASHRAE)
Most air conditioning systems perform the following functions:
- Provide the cooling and heating energy required.
- Condition the supply air, that is, heat or cool, humidify or dehumidify,
clean and purify, and attenuate any objectionable noise produced by the
HVAC&R equipment - Distribute the conditioned air, containing sufficient outdoor air, to the
conditioned space - Control and maintain the indoor environmental parameters–such as
temperature, humidity, cleanliness, air movement, sound level, and
pressure differential between the conditioned space and surroundings—
within predetermined limits
Air conditioning systems can be classified
according to their applications as
(1) comfort air conditioning systems and (2) process air
conditioning systems.
provide occupants with a comfortable
and healthy indoor environment in which to carry out their activities.
Comfort air conditioning systems
provide needed indoor environmental
control for manufacturing, product storage, or other research and development
processes.
Process air conditioning systems
small package type A/C units consist of
direct expansion refrigeration as cooling system, condenser fan, circulating fan,
and control system. It is understood to serve one space or many units serving
larger space.
Window Type Air Conditioners
consist of outdoor unit which are typically
condenser and compressor and the indoor unit that cools air before it is supplied
to the condition space. It is usually installed inside the condition space.
Split Type Air Conditioners
– consist of one indoor unit to match one outdoor
unit.
Single-split A/C units
– consist of one indoor unit to match one outdoor
unit.
Single-split A/C units
– consist of one indoor unit to match one outdoor
unit.
Single-split A/C units
– consist of one indoor unit to match one outdoor
unit.
Single-split A/C units
– consist of one indoor unit to match one outdoor
unit.
Single-split A/C units
consist of two or more indoor units to
match one outdoor unit.
Multi-split A/C units
– larger package type A/C and are usually installed
outside the condition space typically on the roof top of the building where it
served.
Roof Top Package A/C
consist of refrigeration circuit and chilled water
circuit.
Chilled Water A/C units
known as four-pipe
water system normally consist of hot water lines and the heating coils, cooled
water lines and the cooling coils, circulating pumps, air handlers, and controlling
system.
Combined Hot Water and Chilled Water System
Four (4) Necessary Action to operate A/C equipment effectively:
- Action to control the temperature through thermostat and controlling valves
- Humidity control through thermostat and humidifier or duct heater
- Action to filter air through air filtering device on Air Handling Equipment, air
purification including air freshener. - Action control air motion to a given space through circulating fans and
modulating damper.
Four (4) Necessary Action to operate A/C equipment effectively:
- Action to control the temperature through thermostat and controlling valves
- Humidity control through thermostat and humidifier or duct heater
- Action to filter air through air filtering device on Air Handling Equipment, air
purification including air freshener. - Action control air motion to a given space through circulating fans and
modulating damper.
The study of properties of air and water vapor mixture.
Psychrometry
It is a graphical representation of various thermodynamic properties of
moist air.
It is very useful for finding out the properties of air (which are required in
the field of air condition) and eliminate lot of calculations.
Psychrometric Chart
– lines which are vertical, parallel to the ordinate and uniformly spaced.
– actual temperature of the air
Dry Bulb Temperature
lines which are horizontal, parallel to the abscissa and are uniformly space.
is the expression of mass of water vapor per unit mass of dry air.
Specific Humidity or Humidity Ratio
the temperature at which condensation begins if the air is cooled at constant
pressure.
Dew Point Temperature
the temperature of the air if it is saturated.
Wet Bulb Temperature
lines which are inclined straight lines and uniformly space as shown. These lines
are parallel to the wet bulb temperature lines and are drawn up to saturation curve
Enthalpy
lines which are obliquely inclined straight lines and uniformly space as shown.
This lines are drawn up to saturation curve.
Specific Volume
- lines which are curved and follow the saturation curve.
Relative Humidity
The effect of this form of heat is indicated by the sense of touch or feeling. It can
be measured by means of thermometer.
Sensible Heat
Is the quantity of heat which become concealed or hidden inside a body while
producing some change in the body other than an increase in temperature.
Latent Heat
