of 26

# Apprenticeship Day 1b - Physics

128 views

## Content

APPRENTICESHIP:

WHY, OH WHY IS THIS BORING STUFF SUPPOSED TO BE IMPORTANT TO ME???

APPRENTICESHIP: PHYSICS! WHOOPIE! DEFINITION LAWS / TRUTHS HEAT DYNAMIC EQUILIBRIUM!!! HOW DOES THIS APPLY TO ME???

The Physics of HVACR: BASIC PHYSICS PRINCIPLES: BASIC PRINCIPLES THAT DRIVE, VALIDATE, AND EXPLAIN WHAT WE DO ARE BASED ON SCIENTIFIC LAWS, WHICH ARE AN ABSOLUTE OR TRUTH THAT CAN BE TESTED OVER AND OVER AGAIN WITH THE SAME RESULT OR OUTCOME.

The Physics of HVACR: • HEAT EXISTS IN ALL SUBSTANCES, DOWN TO -463DEGREES F; ABSOLUTE ZERO IS -460 DEGREES • HEAT ALWAYS FLOWS FROM A HIGHER TEMPERATURE SUBSTANCE TO A LOWER TEMPERATURE SUBSTANCE, NO MATTER HOW SMALL THE DIFFERENCE MAY BE. • DUE TO THE FRICTION BETWEEN MOLECULES, ALL GASSES BECOME WARMER WHEN COMPRESSED

The Physics of HVACR: • ALL MATTER CONSISTS OF MOLECULES • THREE FORMS OF MATTER; SOLID, LIQUID AND GAS • THE TEMPERATURE AT WHICH A MATERIAL CHANGES STATE (SOLID TO LIQUID, LIQUID TO GAS) DEPENDS ON THE PRESSURE AT WHICH IT IS CONTAINED

The Physics of HVACR: • THERMODYNAMICS IS THE STUDY OF THE INTERRELATION BETWEEN HEAT, WORK AND INTERNAL ENERGY OF A SYSTEM; HOW HEAT IS TRANSFERRED. 1.THERMO-HEAT TRANSFER; AND DYNAMICSENERGY IN MOTION, (for example, MECHANICAL ENERGY) 2.(TEMPERATURE AFFECTS THE OPERATION OF EVERYTHING INSIDE AND OUTSIDE AN HVACR SYSTEM). 3.HEAT, PRESSURE AND VOLUME CHANGES AFFECT THERMODYNAMICS

The Physics of HVACR:

–HEAT IS A FORM OF ENERGY RELATED TO MOVEMENT OF MOLECULES IN A SUBSTANCE. (P.87). a.CONDUCTION(P. 88) b.CONVECTION (P. 89) c.RADIATION (P. 90)

The Physics of HVACR: • ENERGY CANNOT BE CREATED OR DESTROYED • HEAT ENERGY CANNOT BE DESTROYED, ONLY TRANSFERRED (OR CONVERTED) FROM ONE FORM TO ANOTHER.

The Physics of HVACR: • WHEN ONE FORM OF ENERGY IS GENERATED, IT DOES SO AT THE EXPENSE OF ANOTHER FORM OF ENERGY, WHICH LEADS TO THE NEXT TRUTH: • FOR EVERY ACTION, THERE IS AN EQUAL AND OPPOSITE REACTION!

The Physics of HVACR: • HEAT FLOWS FROM WARMER TO COOLER; • THE GREATER THE DIFFERENCE BETWEEN THE TWO, THE FASTER THE HEAT TRANSFER.

LAWS OF VOLUME AND PRESSURE: • BOYLE’S LAW (P. 102): • THE PRESSURE AND VOLUME OF A GAS ARE INVERSELY RELATED: 1.AT THE SAME OR CONSTANT TEMPERATURE; (IN A CLOSED SYSTEM); IF THE VOLUME DECREASES, THE PRESSURE WILL INCREASE AND IF THE VOLUME INCREASES, THE PRESSURE WILL DECREASE. (OPPOSITE, IF TEMPERATURE REMAINS CONSTANT). 2.WORKS ONLY WITH PSIA (ABSOLUTE PRESSURE) P. 102; NOT PSIG

LAWS OF VOLUME AND PRESSURE: • CHARLES’ LAW (P. 103): • AT A CONSTANT PRESSURE, THE ABSOLUTE VOLUME CHANGES DIRECTLY WITH THE ABSOLUTE TEMPERATURE, AND AT A CONSTANT VOLUME, THE ABSOLUTE PRESSURE CHANGES DIRECTLY WITH THE ABSOLUTE TEMPERATURE. (THINK CLOSED HVAC SYSTEM)

LAWS OF VOLUME AND PRESSURE: CHARLES’ LAW (P. 103): KEEPING PRESSURE CONSTANT MEANS:

a.WHEN THE TEMPERATURE INCREASES, THE VOLUME INCREASES b.AS THE TEMPERATURE DECREASES, SO DOES THE VOLUME

LAWS OF VOLUME AND PRESSURE: • CHARLES’ LAW (P. 103):

• KEEPING THE VOLUME CONSTANT: a.WHEN THE TEMPERATURE INCREASES, THE PRESSURE INCREASES b.AS THE TEMPERATURE DECREASES, SO DOES THE PRESSURE

LAWS OF VOLUME AND PRESSURE:

• CHARLES’ LAW (P. 103):

• IN OTHER WORDS, A GAS EXPANDS WHEN IT HEATS, AND IT CONTRACTS WHEN IT COOLS. • GAS PRESSURE GOES UP THE SAME AS THE TEMPERATURE.

LAWS OF VOLUME AND PRESSURE:

–CHARLES’ LAW (P. 103): –TWO THINGS TO REMEMBER: a.TEMPERATURE AND PRESSURE MUST BE EXPRESSED IN ABSOLUTE b.ONLY APPLIES TO PURE GASSES

LAWS OF VOLUME AND PRESSURE: • DALTON’S LAW (P. 104): • THE TOTAL PRESSURE OF A CONFINED MIXTURE OF DIFFERENT GASSES IS EQUAL TO THE SUM OF THE PRESSURES OF EACH GAS IN THE MIXTURE • IN A CONSTANT VOLUME; THE PRESSURES OF DIFFERENT GASSES WILL ADD TO CREATE AN OVERALL HIGHER PRESSURE. THE PRESSURES ARE NOT AVERAGED.

LAWS OF ELECTRICITY: • OHM’S LAW (P. 57-59): • THE PRESSURE DROP, MEASURED IN VOLTS, IS EQUAL TO THE CURRENT FLOW, MEASURED IN AMPERES, MULTIPLIED BY THE RESISTANCE. RESISTANCE IS MEASURED IN OHMS IN HONOR OF WHO DISCOVERED IT.

LAWS OF ELECTRICITY: • OHMS LAW: • E = VOLTAGE; I = AMPEREAGE; R = RESISTANCE

• E = I x R, OR E = IR • (VOLTAGE IS THE PRODUCT OF CURRENT TIMES RESISTANCE)

LAWS OF ELECTRICITY: • OHMS LAW: • WHEN CALCULATING CURRENT FLOW: • CURRENT FLOW EQUALS THE ELECTRICAL PRESSURE DIVIDED BY THE RESISTANCE: • I = E/R, or I=E÷R • E = VOLTAGE; I = AMPEREAGE; R = RESISTANCE

LAWS OF ELECTRICITY: • OHMS LAW: • WHEN CALCULATING RESISTANCE IN A CIRCUIT: • THE RESISTANCE EQUALS THE ELECTRICAL PRESSURE DIVIDED BY THE CURRENT: • R = E/I or R=E÷I • E = VOLTAGE; I = AMPEREAGE; R = RESISTANCE

LAWS OF ELECTRICITY: • OHMS LAW:

• IS ONLY ACCURATE WITH RESTRICTIVE LOADS LIKE ELECTRIC HEAT STRIPS.

MORE PHYSICS LAWS OR TRUTHS: • FORCE IS PORPORTIONAL TO ACCELLERATION • WHAT GOES UP, MUST COME DOWN • PRESSURE MOVES FROM HIGH TO LOW TEMPERATURE

MORE PHYSICS LAWS OR TRUTHS: • EVERY EFFORT HAS A CAUSE • TIME CANNOT BE REVERSED

MORE PHYSICS LAWS OR TRUTHS:

IN ESSENCE, NATURE SEEKS BALANCE - A DYNAMIC EQUILIBRIUM

MORE PHYSICS LAWS OR TRUTHS: • COMBINING THE LAWS AND PUTTING THEM INTO PRACTICE: • THINK COMPRESSORS…SO: TEMPERATURE, PRESSURE AND VOLUME ALL VARY AS THE CONDITIONS OF A COMPRESSOR.

## Recommended

#### info_iec62642-1b

Or use your account on DocShare.tips

Hide