Ammonia

Typically how much superheat is found on the outlet of an evaporator under normal conditions using the overfeed design

0°F

What vapor carries

Heat

Compressor

Reduce volume

1% of air concentration equals

10,000 ppm

Trapped liquid will rise how much pressure per degree

100 to 150 psi page 83

Stop valve has how much flow

100%

Ammonia absorption rate into water

1300 per 1 gallon

Approximately how many BTUs does it take to melt or freeze 1 pound of ice to water at 32°F

144 BTUs

181 psi G equals what pressure in psia

195.7

What is the practical Max compression ratio for a rotary screw compressor

20:1 CR

The pressure gauge is measuring an area of one square inch and there is a force of 30 pounds on the area what is the pressure

30 psi

Typically reciprocating compressor require a minimal differential oil pressure of blank about suction pressure

30 to 40 PSI

54 psia equals what pressure in psi G

39.3

A home air conditioner is rated to remove 48,000 BTUs in one hour what is its tonnage rating

4 ton because 12,000 BTUs in one hour equals 1 ton

What is the practical Max compression ratio for a rotary vane compressor

4:1 CR

Metering valves have how much flow

50%

1 pound of ammonia absorbs

561 BTUs

Approximately how many BTUs does it take to convert 1 pound of saturated liquid ammonia to 1 pound of saturated gas

561 BTUs

Liquid ammonia expands what ratio when changing from liquid to vapor

768 to 1

What is the practical max compression ratio for the reciprocating compressor

8:1 CR

Approximately how many BTUs does it take to convert 1 pound of liquid water at 212°F to steam at 212°F

970 BTUs

Gauge pressure to atmospheric pressure

Add 14.7

TXV evaporator pressure

Always trying to close the valve

TXV spring pressure

Always trying to close the valve

Two-stage compression is considered to be

At least two compressors compressing the gas in a series

Zeotropic and azeotropic our types of refrigerant that are considered to be

Blends or mixtures

Changing the pressure upon a refrigerant changes

Boiling and condensing temperature

56°F is equal to what in Celsius

C equals (F -32)/1.8 13.3

Compressors pump vapor only and they are sized by what requirement

CFM

How are blades forced outwards in a rotary vane compressor

Centrifugal force

What is one of the most important aspects that an operator must look for before starting up a compressor

Check oil levels

Leak coming from non-insulated pipe

Compressor is your enemy

Leak coming from insulated pipe

Compressor is your friend

What component controls the overall highside pressure of a mechanical refrigeration system

Condenser

If you touched a hot ceramic coffee mug with your bare hands this would be an example of what type of heat transfer

Conduction

Metering device

Controls flow

Evaporators can't be coolers freezers a blast freezers etc what is one common application to them all as the refrigerant absorbs heat

Convert liquid to gas by absorbing heat

If using a TXV what style of evaporator are you using

DX

What are the three feeds

DX or dry expansion over feed or recirculated flooded or gravity

To put a solenoid in Auto it's Stem must be screwed

Depends on manufacturer and model

Compression ratio equals

Discharge pressure divided by suction pressure

What style compressor cannot be used in the industrial Ammonia refrigeration system

Dynamic displacement

Hi discharge temperatures are good for a compressor creating a black sooty deposit

False

Semi hermetic pumps have an external motor connected to the Armature with a mechanical shaft seal

False

What is the king valve

First liquid manual closing valve leaving the HPR

If there is a small percentage of ammonia absorbed into the oil it will cause the oil to what when the pressure upon the oil is lowered

Foam

If you say refrigerant is at saturation you're saying there is

Gas and liquid combination

If you say refrigerant and superheated you're saying it is at a temperature above saturation point and a

Gas only

A condenser converse the refrigerant from what to what when it removes heat

Gas to liquid

Condenser

Gas to liquid

What is sensible heat

Heat transfer causing a change in temperature but not a change in state

Arete is a measure of something to a fixed units such as time what is tonnage

Heat transfer in BTUs per time

What is latent heat

Heat transferred that does not change temperature changes state

The four basic components create four secrions of pressure and refrigerabt state. Where is the worst place to have a leak

High side liquid

Which compressor is commonly started first in starting up a two-stage system

High stage compressor

In hot gas defrost

High-pressure gas from the Compressor discharge is piped through the evaporator

IDLH for ammonia

Immediately dangerous to life and health 300 ppm must use SCBA

With an impingement style oil separator what are the steps of separation

Impingement change of direction gravity in coalescing filters

Where should the superheated gas exist in all refrigeration systems

Inlet of compressor

What is specific heat CP

It is the exact amount of heat that must be transferred to change 1 pound of a substance by 1°F

What would cause a TXV to hunt

It's too big. It cannot be stable

What is the style of oil cooling for compressors

Liquid injection thermosiphon water or glycol

If you see refrigerant a sub cool do you were saying it is at a temperature below it saturation point and a

Liquid only

Evaporator

Liquid to gas

Uses of a slide valve

Loading and unloading the capacity control reference to suction pressure run it manually

Rotary vanes are limited to what type of application and ammonia refrigeration

Low stage booster applications of the two-stage system

Air noncondensible gas in an ammonia system will not cause what

Lowering suction pressure

Are oil and liquid ammonia considered to be miscible

No oil is heavier than liquid ammonia

TXV sensing bulb pressure

Only force that can open the valve

In what order must you open valves to work on a strainer

Open stop valve one manually open solenoid three then close stop valve five

What style of System uses a liquid pump to transfer liquid to evaporators

Overfeed

What pressure scale must be used to calculate a compression ratio

PSIA

Flash tax gas example

Page 220

PEL for ammonia

Permissible exposure limit 50 ppm need a respirator

what are two other components that are just as critical as the four steps of refrigeration

Piping and refrigerant

What force opens txv

Powerhead

The compressor controls the low side boiling temperature by controlling

Pressure

The metering or expansion valve controls

Pressure

To classify a metering valve as an actual expansion valve what must happen across the valve

Pressure drop temperature drop increase in velocity

What is not a secondary coolant

R-134a

The glow of the sun would be an example of what type of heat transfer

Radiation

An example of how lava lamp works would be an example of what type of heat transfer

Radiation conduction and convection

Which compressor may have safety Springs internally for liquid

Reciprocating

What are the three styles of positive displacement compressors use in our industry

Reciprocating rotary vane rotary screw

If one drops suction pressure of the refrigeration system what would not happen

Rise in boiling temperature

If one increase superheat on the inlet of a compressor what would most likely happen

Rise in discharge temperature

A compressor is running single stage in the system with the evaporator at -34°F and condensing 89°F what compressor according to compression ratio would be running

Screw because of the high drop

If the compressor took a slug of liquid ammonia in his hydraulically pounding what action must an operator do if all possible

Shut it off and notify management immediately

High level float

Shuts off evaporator and need investigation

Capacity control mechanism of a compressor is actuated by

Suction pressure

In a DX or dry expansion evaporator the refrigerant should leave in what condition

Superheated

All flooded systems are unique in that they supply saturated liquid refrigerant to the bottom of the evaporator from what component

Surge drum

When one drum is full in a double drum system what happens

The one stops pumping

Do twin screws open clockwise or counterclockwise

They open toward suction usually clockwise

How many groups of halocarbons are there

Three groups

An increase of heat on the bulb of TXV causes want through the valve

Valve to stay open or open more

A compressor is considered a

Volume reducer

When should you track oil in a refrigeration system

When it is added and removed

Is 10 psi G a greater pressure than 10 psia

Yes by 14.7 psi

What are the four steps of refrigeration

compressor evaporator condenser metering device