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44 Cards in this Set

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IN A HORIZONTAN SHELL AND TUBE CONDENSER
A-THE WATER IS IN THE-
B-THE REFRIGERANT IS IN THE-
A-TUBE
B-SHELL
THE REFRIGERANT ENTERS THE CONDENSER AS -A__________AND
EXITS AS B_________
A-HIGH PREASURE VAPOR
B-HIGH PREASURE LIQUID
THE FUNCTIONS PERFORMED BY A MEETERING DEVICE ARE ?
1-CONTROL THE FLOW OF LOW PREASURE LIQUID TO THE EVAPORATOR
2-SEPARATE THE HIGH SIDE OF THE SYSTEM FROM THE LOW SIDE
3-REDUCE THE REFRIGERANT PREASURE
1 CONDENSING TON =
250 BTU PER MINUTE
ORIFICE PLATE ?
METERING DEVICE ON A CENTRIFUGAL CHILER
WHAT IS TH FUNCTION OF A PURGER
TO RID A REFRIGERATION SYSTEM OF NON CONDENSABLE GASES
in a cooling tower,for each pound of water that evaporates,how much heat is rejected?
970 BTU'S
AT A GIVEN TEMPERATURE,THE RATIO OF ACTUAL VAPOR IN THE ATMOSPHERE TO THE SATURATION PREASURE IS CALLED
RELATIVE HUMIDITY
If the eliminator fins located below the fan of a enduced-draft cooling tower become cloged what will take place?
cooling water temperature increases
a indication that a systems cooling tower is not operating as designed
high head preasure
witch type of cooling tower or evaporative condencer has a fan at the air inlet
forced draft
why are wet bulb readings generally lower than dry bulb readings
the cooling efect of evaporation
an induced draft cooling tower is one in wich the air?
is pulled through the tower
improperly treated cooling tower water may result in
growth of bacteria and rusty pipes
in a induced draft cooling tower wich is operating efficiently the leaving water temperature is generaly
between the prevaling dry bulb and wet bulb temperature
the reading of a sling pschrometer are in units of
temperature
in cooling towers chemicals are used to?
inhibit rust
a sample of water taken from a cooling tower is fownd to have a ph of 7.8 it can be said that it is
slightly al kaline
a cooling tower should be maintained at a PH value most nearly ?
8
the main reason why cooling towers are provided with a constant water bleed off is to
to prevent a hi build up of solid concentration in the water
if the measured wet bulb and dry buld temperatures have equivalent readings what statement can be made about the conditions of the air ?
the air is saturated with moisture
heat is rejected from a coolig tower when the temperature of the cooling water is ?
higher than the dry bulb temperature
on a humid day when the head preasure is higher than narmal the RMO should ?
turn aditional tower fans on
a sling thermometer is used to?
dry and wet bulb temperatures
on a day the dry bulb stays the same but the wet temperature decreases by 5deg what should the operator observe
lower cooling water temperature being returned
a refrigeration system includes a forced draft cooling tower,an economizer and chilled water as the cooling medium,heat is removed from the building is finaly rejected as?
latent heat of vaporization in the cooling tower
what would cause a condenser waterpump to cavitate?
a faulty cooling tower make-up water valve
the start-up sequence for a receprocating machine should be as follows ?
start cooling tower fan ,start chilled water and condencer water pumps,check oil level,turn on chillers
if the condencer cooling water were to return to a condenser at a temperature of 105 deg what might be rong ?
the cooling fans may be off
what funtion do enviromental stabilizers perform inside of a cooling tower
adjust chemical solutions to inhibit corrosion
the most usefull question to consider in making a decition as to use a roof top unit is ?
will the struture suport the weight of the unit
most factory assembled cooling towers are constructed of ?
galvanized steel
an induce draft cooling tower the lowest leaving water temperature will be obtained when ?
dry bulb is higher than the wet bulb temperature
how would you describe the condition of the air when the dry and wet bulb temperature is equal ?
100% relative humidity
a problem associated with static electricity increase when th ambient air is?
dry
a forced draft cooling tower is used to cool condencer water .the lowest temperature that the leaving water can be reduced to is ?
sligtly higher than the wet bulb teperature
what would cause a decrease in flow rate on a pump operating at normal preasure ?
a Dirty Strainer
a system with two condenser pumps has a total preasure drop of 40 psi.with only one pump running what will be the system preasure drop ?
40 psi
what would cause the condenser water temperature to rise when the pump is running ?
a cloged strainer
whitch valve has he least amount of preasure drop ?
gate valve
how are centrifugal pumps rated ?
G.P.M gallons per minute
proper procedure to turn on a (condenser)pump is suction valve completely open and the discharge valve side
closed until the motor reaches its full RPM
a device that is installed in the chilled water piping to ensure that the chilled water pump is operating is called ?
a flow swith
a condenser water pump has two copper tubes coming out of the top of the pump volute.to the pump shaft,what are the purpose of these tubes
to cool the shaft and bearings