REFRIGERATION 2
Terms
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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 ?
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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