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HVAC Equipment Practice Exam Questions With Correct Answers 2023
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HVAC Equipment Practice Exam Questions With Correct Answers 2023
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HVAC Equipment Practice ExamQuestions With Correct Answers 2023
Absorption Chiller - Answer UTILIZE A THERMAL OR CHEMICAL PROCESS TO
PRODUCE REFRIGERATION EFFECT NECESSARY TO PROVIDE CHILLED WATER
NOT VCR- NO MECHANICAL COMPRESSION
Air Filter - Answer CLEANS THE AIR OF UNDESIRABLE ELEMENTS
sound attenuating filters-reduce level of sound moving through ductwork
Air Handing Unit (AHU) - Answer PREASSEMBLED OR SITE BUILT EQUIPMENT
DEVICE CONTAINING COILS AND FANS THAT IS USED TO CONDITION AND
CIRCULATE AIR AS PART OF AN HVAC SYSTEM
made up of fan(s), cooling and heating coils, dampers, and filters
delivers air to supply air ductwork that conveys conditioned air into zones (rooms)
often integrated ventilation
operation
heating and cooling coils to condition air
dampers control flow
outside air
return air
mixed air
supply (conditioned) air
air filter(s) removes dust particles from air
fans move air and deliver conditioned air to building
Air-Cooled Condenser - Answer PASS OUTDOOR AIR OVER A DRY SURFACE COIL
TO CONDENSE REFRIGERANT CONTAINED INSIDE THE COIL
RESULTS IN HIGHER CONDENSING TEMP AND LOWER PERFORMANCE UNDER
PEAK CONDITIONS COMPARED TO WATER COOLED CONDENSERS
Air-Source Heat Pump - Answer (LIKE A REFRIGERATOR)
USES ELECTRICITY TO MOVE HEAT FROM COOL SPACE TO WARM PLACE.
OUTSIDE AIR OR WATER IS HEAT SOURCE
water-source heat pumps- use water in pond or lake as heat source
Air-Water HVAC System - Answer CONSISTS OF AN AIR SIDE AND A WATER SIDE,
WHICH CONTRIBUTES TO HEATING, COOLING, AND VENTILATION
,Heating/cooling delivered via local equipment
Have an air side and a water side
Includes chiller(s), boiler, and room terminal units with ventilation
Delivers a combination of heated/cooled air and hot/chilled water to space
(Large building/large application)
Advantages:
individual room control allows independent heating and cooling
fair reliability - only single zone affected by malfunction
low initial cost
Disadvantages
short life
noise within space
poor humidity control, air filtration, and ventilation
All-Air HVAC System - Answer HEAT, COOL, VENTILATE BY PROVIDING AIR ONLY
TO THE SPACE BEING CONDITIONED
Cooled/heated air from central plant/AHU via ducting
Includes chiller(s), boiler(s), AHUs, terminal boxes
AHUs deliver heated/cooled air to space through ductwork
Advantages
heating/cooling delivered via air only allows good temperature and humidity control
good humidification and heat recovery
allows for complex zoning
can use outside air for economizer cycle
Disadvantages
special care for maintenance access
greater volume of equipment space needed
supplemental perimeter radiation may be needed
Types
Constant Air volume (CAV or CV)
single zone
terminal reheat
multizone
dual duct
Variable Air Volume (VAV or VV)
Variable Volume Variable Temperature (VV-VT)
,(Large building/large application)
supply air ducts
supply (conditioned) are from AHU to diffusers/registers
introduces supply air to occupied space
return air ducts
removes air from building spaces
returns air to air-handling unit, which reconditions some air
some air is exhausted
Exhaust Air ducts
return air exhausted to building exterior
Outdoor air ducts
supplies outdoor air to air-handling unit
Used for ventilating occupied building spaces
Mixed Air Duct
mixed outdoor air and return air in chamber
supplies mixed air to air-handling unit
Extended plenum supply
Individual Supply system
Perimeter-loop system
Trunk duct - 2 way
Trunk Duct - 1 way
Full Exhaust- 100% Outside Air
no return air because the return air may contain contaminants
Mixed Air
outside air is combined with return air
All-Water (Hydronic) HVAC System - Answer HEAT AND COOL BY CIRCULATING
HOT WATER FROM A BOILER OR CHILLED WATER FROM A CHILLER THROUGH
A FINNED COIL IN A FAN-COIL UNIT OR UNIT VENTILATOR IN THE SPACE
Basic types:
steam
hot water
chilled water
Chiller plant (or chiller) plus boiler to produce conditioned (chilled and/or hot) water
Includes chiller(s), boiler(s), and room terminal units
Conditioned water is pumped to room terminal units (ie. convectors, convector-
radiators, chilled beams, etc.)
, (large building/large application)
system components
piping/fitting
equipment and distribution
valves
pumps
terminal devices (heat/cool emitting)
Piping arrangements
one pipe
two pipe* (two pipe changeover)
three pipe*
four pipe*
water-loop heat pump
*these arrangements can be used to deliver hot water and chilled water to AHU in all-air
systems
one-pipe hydronic series loop
have a single pipe that acts as the supply pipe and the return pipe for the flow loop,
connecting one terminal unit to the next terminal unit
two-pipe hydronic system
have a separate supply pipe and return pipe at each terminal unit
Two pipe direct return
return water from each unit takes shortest path back to boiler
with valves in branch lines, each unit can be controlled and serviced separately
Two pipe reverse return
main flow is in same direction as supply flow
offers easier balancing
Three pipe systems
have a hot-water loop and a cold-water loop so that hot or cold water can be introduced
to any terminal unit at any time
a single "common" return is used
provide both supply heating and chilled water to units
hot water, chilled water, common return
three way modulating valve at inlet of unit allows hot or cold water depending on load
water leaving unit is carried in a common return pipe to either chiller or boiler- inefficient
Four Pipe System
uses supply and return heating piping and supply and return cooling piping
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