ECT 13 Fundamentals of Refrigeration (Laney Fall 2024) PDF

ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) Owner R Ryan Tags Module 1 - Heat, Temperature, Pressure work Whitman_8e_Ch01.pdf Heat, Temperature, P...

ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) Owner R Ryan Tags Module 1 - Heat, Temperature, Pressure work Whitman_8e_Ch01.pdf Heat, Temperature, Pressure Heat → motion of molecules, flow or movement of thermal energy between objects with different temperatures As a substance receives more heat, its molecular motion, and therefore temperature increases Laws of Thermodynamics heat (energy) cannot be created or destroyed (except in nuclear reactions) heat can be measured and accounted for (by measuring temperatures) heat can be transferred from one substance to another heat travels from a warmer substance to a cooler substance Heat can be transferred by conduction, convection, or radiation Conduction → heat energy travels from one molecule to another within a substance, from one substance to another heat does not travel or conduct at the same rate in all materials ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 1  example: copper rod placed in the flame will get hot at the end of the rod away from the flame Convection → heat transfers through fluid from one substance to another natural convection uses natural fluid flow, warm air rises and cooler air falls forced convection uses fans or pumps to move fluids Radiation → Heat energy transfer via radiation occurs through electromagnetic waves, primarily in the form of infrared radiation (sunlight warming the earth, heat from a fire, radiant heaters, heat from asphalt, cooling of earth at night, heat from a light bulb) radiant heat passes through air, heating the first solid object with which the heat comes in contact these heated objects, in turn, heat the surrounding area (infrared radiation) radiant heat can travel through a vacuum ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 2  radiant heat can travel through space without heating it Sensible Heat → the energy that changes a substance's temperature without changing its phase Latent Heat → latent heat is the energy that changes a substance's phase without changing its temperature Latent heat of vaporization → amount of heat absorbed when a liquid turns into vapor Latent heat of condensation → amount of heat released when gas particles condense into liquid droplets ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 3  Latent heat of fusion → amount of heat absorbed when a solid turns into a liquid We can calculate the heat released or absorbed using the specific heat C, the mass of the substance m, and the change in temperature delta T in the following equation q = quantity of heat needed for the temperature change each substance has its specific heat the formula below can be used to estimate the BTU's needed for the desired temperature change ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 4  q = quantity of heat needed m = mass C = specific heat delta T = change in temperature British Thermal Units (BTUs) BTU is used to describe the amount of heat energy or heat content contained in a substance rate of heat transfer can be determined by the time it takes to add or remove heat e.g., 24,000 BTU/hr means that an air conditioning can remove 24k BTU of heat in an hour one BTU of heat energy is required to raise the temperature of 1lb of water by 1 degree F specific heat capacity → the number of BTUs required to raise the temperature of 1 pound of a substance 1 degree Fahrenheit Temperature → A measure of the average kinetic energy of particles in an object, relative to another object level of heat or heat intensity higher temperature means faster molecule movement ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 5  Relative terms are usually hot and cold, but this is not a precise description temperature can be measured with thermometers in Celsius (°C), Kelvin (K), Fahrenheit (°F), or Rankine (R) -460F/-270 C temp at which all molecular movement stops Converting Temperatures Celsius (C) to Fahrenheit (F) Fahrenheit (F) to Celsius (C) temperature difference is the driving force behind heat transfer ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 6  heat flows naturally from a warmer (more molecular motion) to a cooler substance (less molecular motion) Pressure → force per unit area often expressed in pounds per square inch (psi) atmospheric pressure → atmosphere that we live in exerts a weight at 14.696 psi at sea level (15 psi) known as the standard condition measured with barometer barometer ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 7  bourden tube (psig) 1. Reading Notes - Chapter 1 a. standard conditions i. atmospheric pressure at sea level (14.7 psia) is the standard condition compared to the pressure at elevation (water boils faster ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 8  at higher elevation due to the increased pressure at higher elevation) b. absolute zero i. used for performance ratings of equipment 1. Absolute temperature, also known as thermodynamic temperature, is a measurement of temperature on a scale where zero is absolute zero, the coldest possible temperature. At absolute zero, the motion of gas particles stops, and the gas's volume is zero. a. Absolute temperature is measured in kelvins (K) using the formula i. T(K) = T(degree C) + 273.15 c. pressure i. force per unit area 1. water weighs 62.4 lb/ft3 2. when you increase the surface area of something you reduce the amount of pressure that it exerts a. e.g., snowshoe ii. pressure gauges 1. low and high-pressure gauge a. left side = compound or low pressure gauge = pressure above and below atmospheric pressure b. right side - high pressure gauge = pressures up to 500 psi c. gauges read 0 psi when opened to the atmosphere i. if they do not read 0 psi then they need to be calibrated ii. gauges are designed to read psig = pounds per square inch gauge pressure iii. atmospheric pressure is used as the starting point ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 9  1. absolute pressure = gauge pressure reading + atmospheric pressure (14.696 psi) iv. Module 2 - Matter and Energy Whitman_8e_Ch02.pdf 1. Matter → any substance that occupies space and has mass a. Overview i. made up of atoms 1. atom → smallest amount of a substance that can combine to form molecules ii. mass → amount of matter in an object (numerical measure of inertia and resistance to acceleration) 1. weight → combined effect of substance’s mass and the force of gravity pulling down on an object ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 10  a. weight = mass * acceleration of gravity b. weight is the force that matter applies to a supporting surface when it's at rest 2. density → mass contained in a particular volume (water has a density of 62.4 lb/ft3) a. ex: wood floats on water because the density of wood < density of water b. specific gravity → density of a substance divided by the density of water i. uses water as a reference ii. if the specific gravity is higher than water then it will sink in water and if the specific gravity is lower than water then it will float 3. specific volume → volume of one pound of gas (ft3/lb) a. requires that there only be 1 lb of gas b. when air is heated specific volume increases and the air becomes lighter, when air is cooled specific volume decreases and the air becomes heavier c. specific volume and density are considered inverses of each other d. specific volume is used to determine the fan or blower horsepower needed b. States of matter (depends on the heat content of the matter) i. solid 1. definite shape and volume 2. exert all pressure downward 3. molecules have a great attraction to each other and hold together a. very little space between particles and they can only vibrate ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 11  ii. liquid 1. definite volume, but can change shape by flowing 2. exerts pressure outwards and downwards a. pressure is proportional to the depth 3. particle loosely bonded and have more movement than solids 4. take the shape of their container, but maintain a constant volume iii. gas 1. no definite volume or shape 2. exerts pressure in all directions 3. can only be contained in a container or held together by the gravitational pull a. molecules travel at random 4. particles are spread out and have big distances between them iv. plasma c. Gas Laws i. Rules 1. always use absolute pressures and temperatures when working with gas laws a. °R=°F+460 (459.67 to be precise) ii. Laws 1. NOTE: Always use absolute scales of pressure (psi) and temperature (Rankine or Kelvin) ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 12  a. absolute scales use zero as their starting point because zero is actually where molecular motion begins 2. Boyle’s Law a. inverse relationship between pressure and volume, when temperature is constant b. as pressure on gas increases, volume on gas decreases and vice versa i. 3. Charles’ Law a. direct relationship between temperature and volume, when pressures are constant b. volume of a fixed mass of gas is directly proportional to the temperature (K) if pressure is held constant i. as temperature increases volume increases ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 13  4. General Law of Perfect Gas a. for any gas, its volume (V) multiplied by its pressure (P) is equal to the number of moles of gas (n) multiplied by its temperature (T) multiplied by the ideal gas constant, R. b. The Ideal Gas Law states that i. volume of a gas is directly proportional to its temperature and the number of gas moles ii. the volume of a gas is inversely proportional to its pressure iii. PV = nRT 1. molecules of gas are always in motion ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 14  5. Dalton’s Law a. the total pressure of a gas is equal to its partial pressures i. each type of gas (nitrogen - 78.1%, oxygen - 20.9%, Argon - 0.9%, each gas exerts its partial pressure) d. Energy i. Conservation of Energy 1. Energy is neither created nor destroyed but can be converted from one form of energy to another ii. Energy Contained in Heat 1. heat is thermal energy (motion of molecules) a. thermal energy in a substance is available at most temperatures iii. Energy in Magnetism ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 15  1. magnetism → a method of converting electron flow to usable energy a. electron flow is used to generate magnetic fields that are used to turn motors iv. Purchase of Energy 1. Electricity is measured and purchased in kilowatt-hr (kWh) v. Forms of Energy 1. chemical a. energy comes from bonds between atoms (fossil fuels like gas or oil that come from decayed vegetable and animal matter) 2. nuclear a. energy is released when the nuclei are combined (fusion) or split apart (fission) 3. gravitational a. energy held by an object when it is in a high position compared to a lower position 4. thermal a. vibration of atoms and molecules within substances 5. mechanical a. energy stored in objects; as objects move faster, more energy is stored b. wind, river, moving car, person running 6. electrical a. movement of electrons (the tiny particles that make atoms, along with protons and neutrons) i. Electrons that move through a wire are called electricity ii. Lightning is another example of electrical energy. 7. radiant ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 16  a. light or electromagnetic energy b. sun, x-rays, and radio waves 8. light a. consists of photons, which are produced when an object's atoms heat up b. Light travels in waves and is the only form of energy visible to the human eye 9. sound a. movement of energy through substances b. moves in waves making an object vibrate 10. elastic a. form of potential energy stored in an elastic object b. spring or elastic band vi. Energy Flow 1. heat flows from the substance with a higher temperature to one with a lower temperature vii. Energy Used as Work 1. Work = Force * Distance a. force is given in foot-lbs b. work is the energy transferred (force) to or from an object moving the object in the direction of the force i. for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled 1. A force is said to do positive work if it has a component in the direction of the displacement of the point of application ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 17  2. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force c. Forces https://science.nasa.gov/universe/overview/forces/ 2. Power a. the rate of doing work i. work per unit of time (ft-lbs/min) ii. rated in horsepower 1. 1 hp = 33,000 ft-lbs/min iii. electrical power is measured in Watts 1. 1 hp = 746 watts 2. 1 watt = 3.413 Btu 3. 1 kW = 3,413 Btu iv. Sources https://mhi-inc.com/Converter/watt_calculator.htm 1. https://mhi-inc.com/Converter/watt_calculator.htm Module 3 - Refrigeration and Refrigerants Whitman_8e_Ch03.pdf ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 18  1. Refrigeration a. Overview i. Categories of Refrigeration 1. ultra low temp = -80 Deg C a. uses a cascading structure to achieve lower temperature 2. the temperature desired will determine the type, structure of the system, and the refrigerant type ii. Refrigeration System Design 1. when you design a system you try to ensure that the system can provide capacity in all weather conditions 99.8% of the time a. sometimes you can make it smaller to save on cost, but you may exceed the capacity ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 19 ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 20  b. 2. b. Process i. refrigeration is the process of removing heat from an area of lower temperature to an area of medium or high temperature 1. process of transferring heat from where it makes little or no difference 2. heat flows from warmer substance to cooler substance 3. 1 ton of refrigeration capacity or cooling = 12,000 btu/hr a. 200 Btu/min 4. 144 BTU of heat energy to melt 1lb of ice at 32F a. 1 ton (2,000 lbs) of ice will require 288K btu to melt (144 Btu * 2000 lbs) c. Purpose i. cooling preserves products and provides comfort 1. at higher temps: air conditioning for comfort (70F-75F) 2. at moderate temps: fresh food preservation (35F - 40F or below) ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 21  3. at low temps: frozen food preservation (0F in the freezer) - prevents bacteria growth d. Components 1. Evaporator → absorbs heat from the medium (e.g., air) to be cooled a. operates at lower temperatures than the medium being cooled or conditioned ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 22  b. located on the low-pressure side of the system between the metering device and the compressor c. allows the heat to boil off the liquid refrigerant to a vapor in its tubing bundle d. allows the heat to superheat the refrigerant vapor in its tubing bundle e. NOTE: it’s important to cover the suction line with insulation to prevent the line from absorbing heat from the surrounding air in the room ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 23  f. absorbs heat by boiling a low-temperature liquid into a low- temperature vapor i. refrigerant enters the evaporator as a liquid/vapor mix (75% liquid/25% vapor) 1. when the evaporator absorbs heat, it superheats the liquid/vapor mixture so that the liquid refrigerant is all turned to vapor (don’t want liquid refrigerant in the compressor) a. superheat = evaporator outlet temperature - evaporator saturation temperature b. design superheat is between 8F-12F c. superheat does not follow a P/T relationship 2. Compressor → creates pressure difference so that gas becomes superheated gas and circulates refrigerant through the system a. can be considered a vapor pump b. increases pressure to move vapor from the evaporator to the condenser i. reduces pressure on the low-side ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 24  ii. increases pressure on the high-side iii. pressure difference is what causes the refrigerant to flow c. can only operate with gas, do not want liquid refrigerant in the compressor d. Types i. scroll ii. reciprocating iii. rotary iv. positive displacement 1. require compressed gas to be moved to the condenser e. Motors i. Three Phase Motors 1. Overview a. low operating costs b. lower amperage circuit c. high starting torque d. no start components needed e. subject to phase loss and voltage unbalance 2. Motor Starter ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 25  ii. Single or Split Phase Motors 1. Split phase has two windings a. Run winding and Start winding 1. start winding will have higher resistance and smaller wire a. In a single-phase motor, the "start winding" (also called auxiliary winding) is used to create a rotating magnetic field necessary to initially start the motor by providing a phase shift with the "run winding" (main winding), while the run ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 26  winding is designed to maintain the motor's rotation once it reaches operating speed; essentially, the start winding helps the motor get going, and the run winding keeps it running smoothly. b. Start relay will disconnect the start winding once the motor is up to 75% to 85% speed 2. Motor speed based on the number of poles a. the more poles the lower the speed 3. Calculating nominal motor speed a. one cycle has two flow reversals b. 60 cycles has 120 flow reversals c. Speed = 60Hz * 120 reversals) / Poles i. RPM = (f * 120)/No. of Poles 4. Capacitor Starting ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 27  1. Current Relay a. used on compressors under 1 HP b. switch contacts are normally open 1. LRA = locked rotor amps → the highest current that the motor could ever draw, at start-up usually 2. RLA = rated load amps → the amount of amperage a compressor or condenser draws while operating, minus the start-up draw ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 28  2. Start Capacitor a. increases starting torque and provides more phase shift to start winding b. only in the circuit for a few seconds c. some have bleed resistors (discharges capacitor charge to prevent excessive arcing d. rated in micofarads ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 29  e. Capacitor Tester i. provides actual capacitance ii. perfect MFD range is in the middle and acceptable is within upper and lower values ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 30  iii. when replacing capacitors they have to be the same microfarad range or higher than what you have already 3. Potential Relays a. used for starting single-phase compressors up to 5 HP b. contacts are normally closed c. relay coil is energized by BACK EMF (electromotive force) generated in the starting winding ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 31  4. Run Capacitor 5. Motor Overloads a. internal b. external (thermodisk) compressor overload responds to amperage and temperature (heat) ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 32  1. shorted winding can come from refrigerant and oil in compressor which will result in acid in the compressor 5. 3. Condenser → rejects sensible and latent heat that was absorbed by the evaporator, compressor (friction), and suction line a. located on the high-side of the system and receives gas through the hot gas or discharge line b. refrigerant condenses from a high-temperature, high-pressure superheated vapor to a high-temperature liquid ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 33  i. condensing temperature is determined by the head/high side pressure in the system ii. refrigerant is condensed from a vapor to a liquid 1. this is latent heat transfer iii. the high-side gauge pressure is coming from the condenser and this is called head/high-side pressure or discharge/condensing pressure c. refrigerant is subcooled liquid at the outlet of the condenser i. subcooling → cooling of liquid refrigerant below its saturation temperature 1. standard air-cooled systems designed to operate within 10F of subcooling a. high-efficiency condensers operate with more subcooling 2. subcooling = condenser outlet temperature - condenser saturation temperature 3. refrigerant can be subcooled to 10F-20F below the condensing temp 4. Metering Device → regulates refrigerant flow to the evaporator a. controls the flow of subcooled liquid from the condenser to the evaporator i. creates a pressure drop between the high and low-pressure sides of the system 1. 25% of liquid leaving the metering device immediately vaporizes (flash gas) ii. common types 1. capillary tube ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 34  2. automatic expansion valve 3. thermostatic expansion valve a. TEV will have a tube that senses the temperature of the vapor leaving the evaporator i. if there is too much liquid it is called over 5. Other Scenarios e. Refrigerants i. boil at low pressures and temperatures (at atmospheric pressure) ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 35  ii. condense at high pressures and temperatures iii. saturation temperature → point at which the addition or removal of heat will result in a change of state 1. during a change of state, the temperature remains constant iv. Safety 1. illegal to vent refrigerant to the atmosphere (stiff fines) 2. mandatory certification for technicians 3. refrigerant phase-out set by EPA 4. refrigerant cylinders/drums color-coded 5. proper ventilation is required a. refrigerants can displace oxygen if permitted to accumulate v. Detection ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 36  1. soap bubble testing 2. halide leak detector (required open flame) 3. electronic (general area leaks) 4. ultraviolet (pinpoints leaks) 5. ultrasonic (sound waves) 2. Air Conditioning a. air conditioners remove heat from inside to outside i. usually try to aim for a +10F increase in pre and post-heat absorption on the evaporator (indoor coil) ii. generally the condenser (outdoor) coil needs to be +30F compared to the outdoor temperature to dissipate enough heat off of the coil b. Temperature and Pressure Relationship i. water boils at 212F at atmospheric pressure (14.7 psia/29.92 Hg) 1. if you increase pressure then water boils at 250F (15 psig) 2. if you decrease pressure then water boils at 40F (0.248 Hg) ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 37  3. Pressure Enthalpy Chart (PH Chart) 4. Heat Leakage a. cold air has higher density and sinks leaving a fridge/space while hot air has lower density and rises replacing the air at the top of the fridge/space 5. Lecture Notes a. Refrigeration i. process of removing heat and moving it to where it makes no difference ii. types 1. high (for comfort) - 70-75F 2. moderate (for fresh food storage) - 35-40F 3. low (for freezing items) - 0F ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 38  Module 4 - Safety, Tools and Equipment, and Shop Practices ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 39  Whitman_8e_Ch05.pdf 1. Pressurized Cylinders 1. pressurized cylinders should be chained and moved on an approved cart and the protective cap must be secured a. if the cylinder valve breaks off then the cylinder becomes a projectile until the pressure is exhausted 2. Electrical Hazards a. Safety i. follow lock-out tag-out procedures ii. do not come into contact with energized conductors b. Electrical Shock i. occurs when you become part of a circuit ii. voltage, current, and path of current determine the severity of shock 1. wear insulated boots and do not stand in water while working on electrical equipment 2. grounding wires provides protection 3. battery operated tools are safer ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 40  c. Electrical Burns i. avoid wearing metallic jewelry ii. never use a screwdriver in an electrical panel when the power is on iii. burns can result from electrical sparks d. Short Circuit Hazards 1. power is on and the screwdrivers becomes a part of the circuit 3. Ladder Safety a. Overview i. use non-conducting ladders (wood, fiberglass) ii. place ladders on a level surface iii. do not use damaged ladders iv. keep ladders free of oil, grease or other slipping hazards ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 41  b. Placement i. there should be 3 feet above the upper landing surface ii. the angle of the ladder should be 1/4 the working length of the ladder away from the wall 4. Heat a. Torches i. keep fire extinguisher nearby ii. use a fire shield when soldering near combustibles iii. never solder tubing on a sealed system 5. Cold a. liquid refrigerant can cause frostbite b. R-22 boils at -41F at atmospheric pressure 6. Mechanical Equipment a. be aware of any clothing that can get caught in fans, belts, pulleys, gears, or other equipment b. never try to stop rotating machinery by hand c. always use eye protection when working near rotating machinery 7. Refrigerants in Your Breathing Space a. refrigerant gases are heavier than air i. these gases displace oxygen ii. use proper ventilation iii. ASHRAE Standard 34-1992 addresses refrigerant toxicity and flammability ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 42  8. Chemicals a. follow the manufacturer’s directions b. can irritate the eyes, skin, and throat Chapter 5 - Safety, Tools, Equipment and Shop Practices Whitman_8e_Ch06.pdf 1. Screwdrivers a. Types i. Philips ii. straight or slot blade (flat) iii. offset b. Bit Types i. keystone ii. hex head iii. clutch head iv. square recess 2. Wrenches a. Socket with a ratchet handle ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 43  b. open end or box end c. adjustable open end (crescent or engineer’s wrench) d. ratchet box e. pipe wrench f. t handle hex keys (Allen wrenches) 3. Drivers a. assorted nut drivers b. flare nut wrenches c. hex and box wrench reversible ratchets (service wrenches) 4. Pliers a. general purpose b. needle nose c. side cutting d. slip joint e. locking 5. Hammers and Drills a. Ball peen b. soft head c. carpenter’s claw d. portable electric drill or cordless 6. Mirrors, Wire Tools, and Tackler a. inspection mirrors i. stainless steel and telescoping b. wire strippers and crimping tools c. stapling tackler 7. Tubing Tools ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 44  a. modern tubing cutter b. inner-outer reamers c. deburring tools 8. Flaring and Swaging Tools a. Flaring i. flaring bar ii. yoke iii. feed screw with flaring cone b. Swaging Tool Types i. Punch ii. Lever iii. Die c. Tubing Brushes and Shears 9. Gauge Manifold a. reads pressures on the low and high sides of the system b. reads pressures below atmospheric pressure on the low side of the system c. can be a two or four-valve variety 10. Electronic Thermistor Vacuum Gauge a. measures the vacuum in a refrigeration system during the evacuation process b. as the vacuum is pulled on a system the micron level will drop 11. Vacuum Pump a. designed to remove air and non-condensing gases from an air conditioning or refrigeration system 12. Leak Detectors ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 45  a. Halide i. used with acetylene or propane gas ii. the flame heats a copper disc iii. combustion air is pulled through a tube iv. the open end of the tube is passed over the fitting or piping v. if the flame changes colors then there is a leak b. Electronic and Ultrasonic i. refrigerant sensitive element reacts to leaks with beeping ii. uv lamp versions glow at the point of leak iii. ultrasonic version detects the sound of escaping refrigerant 13. Other a. Thermometers b. Heat guns c. Fin straighteners d. hermetic tubing piercing valves e. compressor oil charging pump f. soldering and welding equipment g. psychrometer h. air velocity instruments (anemometer) i. air balancing meter j. CO2 and O2 indicators k. combustion analyzer l. Multimeter m. Clamp On Ammeter or Multimeter Chapter 7 - Tubing and Piping ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 46  Whitman_8e_Ch07.pdf 1. Tubing and Piping a. ECT 13 - Fundamentals of Refrigeration (Laney Fall 2024) 47