Ma_am Pabello_s PPT. Lesson BU2.pptx

7/25/2019 Ma_am Pabello_s PPT. Lesson BU2.pptx

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Principleof

Electricit y

BuildingUtilities 2



BuildingUtilities 2Electricity • In terms of natural resources electricity is an expensive form of energy• Electricity ow trough wires on other conductors• Voltage is equivalent to pressure; wire resistance to pipe friction; and

electric current on ow of electrons to water droplets.

Energy – from Gree word !Energeta" means wor.# capacity to mae things happen.

Two types of Energy sources:$. %E&E'#()E *naturally replenished+

• ,olar• 'ind• )ightning• -ydro• Geothermal• (iomass

. &/&0%E&E'#()E *natural resource which can not 1e re0grown+• 2ossils fuel• 3oal• /il4 5etroleum•

&atural Gas *6ethane+



BuildingUtilities 2 Ampere *a11reviation A+• It is the 1asic unit for measuring ow of current the unit owing is the

E)E37%I3 3-#%GE8 called !COULOMB”. #n ampere is equivalent to a

ow of one coulom1 per second.• /ne source of direct current is the 1attery which coverts chemicalenergy into electric energy.

Oms *9+• It is the 1asic unit for measuring ow of resistance through a wire.•

8epends on the wire materials. 6etals lie copper and aluminum havelow resistance and classi:ed as a CO!"UCTO#.

Oms Law

,tates that the voltage E *volts+ required to cause a ow of current $

*ampere+ through a wire with resistance # *ohms+ is given 1y E % $# or$ % % A < AMP

Power P Is measured in watts and is the product of volts and amperes.

)arge amount of powers is measured in &ilowatts *'( +# unit of )*** ( = or megawatts +M(,- a unit of



BuildingUtilities 2Power Transmission – power I usually transmitted at very high voltageto minimi?e the power loss over distances.

Circuit Arrangementa, /eries Circuit – a series circuit is one in which the same current ows

through all parts of the circuit.

Example of Series Circuits– 3hristmas )ights4 if one light is out the whole circuit

cannot wor. – ,ignage ' series of lights.



BuildingUtilities 20., Parallel Circuit – 'hen two or more 1ranches on loads in a circuitare connected 1etween the same two points.

@A #65,

@A #65, @A # $B#

#

(

5I37/%I#) ,3-E6#7I3

#%3-I7E37C%#)

5)#&



BuildingUtilities 2"irect Current 1 'henever the ow of electric current taes place at aconstant rate= practically unvarying and in the same direction around thecircuit.

Graphic Representation of DC voltages with positive and negativepolarit!

Alternating Current •

'henever the ow of current I periodically varying in time and indirection.

• #lternating current I produced commercially 1y an #3 generator calledan alternator.

Energy• Is the technical for the more common expression 0 wor.• In terms of power= it is the product of power and time.



(att • Is the unit of electric power *w+• # larger unit of $AAA watts is the ilowatts *w+

Electric /er2ice 1 Is normally tapped onto the utility lines at a mutuallyagreea1le point at or 1eyond the property line.

BuildingUtilities 2

5#&E) (/#%8*3I%3CI7

(%E#DE%+

G%/C&8)I&E

D'- 6E7E%,IE /2 6#I&'I%E

Panel 0oar3 – ,erves 1asically the same function as a switch1oard.Con3uctors – 7he current is conducted through the electrical system=corresponding to the piping in the hydraulic analogy .Circuit 0rea&ers – 7his is an electromechanical device that performs thesame protective function as a fuse in addition acts as a switch.



BuildingUtilities 2Ca0le tray – is a continuous open support for approved ca1les.

/witces – Is a device intended for on4oF control of an electrical circuitand is rated 1y current and voltage= duty poles and throw fusi1ility andenclosure.

(iring "e2ice – 8evice that are normally installed in the wall outlet1oxes= including receptacles= switches= dimmer etc.#eceptacles – Identi:ed 1y the num1er of poles and wires and whether ornot the device I designed for connection of a separate grounding wire.$nsulator – used as supports and for additional protection for wires.

,I&G)E *,$+

,'I73-

8/C()E*,+

,'I73-

"ra

#nsulated Ca$le



BuildingUtilities 2

4le5i0le Metal Cla3 Ca0le +B6, – 6ost common types of ca1le runwithout raceways. 7rade name !(".

%-' – 6oisture – and heat resistance ru11er – 8') 7 – 7hermoplastic – 8) 7' – 6oisture – %esistance 7hermoplastic – 8') 7--& – -eat – %esistance 7hermoplastic

7-' – 6oisture and -eat %esistance 7hermoplastic

Close raceways – included conduit pipe= surface raceways and under

oor ducts which are :rst installed= then the wiring is inserted and pulledin later.

"%&E AC '(E)#B(E AR*+REDCAB(E ,B)-



BuildingUtilities 2#.+ /teel Con3uit 7he purpose of conduits is toa. 5rotect the enclosed wiring from mechanical inHury and corrosion.1. 5rovide a grounded metal enclosure for the wiring in order to avoidha?ard.c. 5rovide a ground path.d. 5rotect surrounding against :re ha?arde. ,upport the conductors

(.+ %igid 6etallic or %aceway 'ays in which steel conduit is manufactureda. -ot – d.p. galvani?ed *dipped in molten ?inc+1. Enameled *coated with corrosion – resistant enamel+c. ,herardi?ed *coated with ?inc dust+d. 5lastic covered

7he nominal trade si?es of conduits are



BuildingUtilities 2

7eat an3Moisture in

te

Atmosperean3 7uman



BuildingUtilities 2Meta0olism – low grade 1urning process suJcient to maintain a 1ody

temperature of KL.M. 2 *@N.3+ – 7he meta1olism unit corresponds approximately to @MA (ritish

thermal unit per hour *(7uh+.

'omen tend to have maximum levels a1out @AO lower.*eta$olic Rate at di/erent tpical activities0

6eta1olic rate in 6E7 units *met. meta1olic+%esting 0A.N to $.'aling to mph 0.AA to @.L(aset1all 0B.AA to N.M

Exercises *3alisthenics+ [email protected] to .AA

Ex.2or a person sleeping= the heat given oF is- A.N x @MA < B (tuh# 1aset1all player in action generates and loses N.

-N.M x @MA < $@M (tuh

-eat lost from the 1ody 1y several diFerent methods.- (y dry – 1ul1 *air+ temperature.

"emperature of surrounding surfacesM#T – 6ean radiant temperature#7 – %elative humidity and air motion



BuildingUtilities 2

"1ER*A( EU#(#BRU* A3D C+*'+R" ,"hermal Environment-

It 1ecomes apparent that the thermal Environment may1e regulated topermit an easy and comforta1le rate of loss for the heat that I generated1y humans for any given activity.

7he term environmental comfort has taen on a 1road meaning= they

include item such as aesthetics and acoustics.2actors that can 1e controlled 1y #3C systems.a. 7emperature of the surrounding air1. 6ean radiant temperature of the surrounding surfacec. 7he relative humidity of the air.d. 6otion of the air

e. /dorsf. 8ust



a. Good 2acing,outh

c. Good 2acing 'est or,outh

1. Good 2acing East or'est

BuildingUtilities 2

-igh

planting

-igh and

lowplanting

Exterior(aPes

Increasing the num1er of people occupying a space already adHusted topro thermal conditions. #3C

5roper location is necessary

a. Very5oor

,un direct through glass

c. Good 2acing ,outh1. 5oor



BuildingUtilities 2"%&ES +' C+*&RESS+R

Compressor – Is considered the heart of the refrigerator system. – It is a pump lie the heart in the circulatory system of the human

1ody.

"pes of compressor$. %eciprocating compressors are categori?ed 1y the compressorQs

housing and 1y the drive mechanisms..@.@. 3ondenser – is a heat exchange device similar to the evaporator

that reHects the heat from the system a1sor1ed 1y the evaporator.

"4+ "%&ES +' C+3DE3SER. 'ater 3ooled 3ondenser@. 7u1e 3ondenser

E2aporator – a1sor1ed the heat in to the refrigeration system



BuildingUtilities 2RE'R#GERA"#+3 C++(#3G S%S"E*

%efrigerated air conditioning is similar to the commercial refrigeration1ecause the same components are

$. 7he evaporator. 7he compressor@. 7he condenser. 7he metering device

"%&ES +' A#R C+3D#"#+3#3G

$. Pac&age air con3itioning – the four components are assem1led intotwo 1asic types of equipment for air conditioning purposes

0 5acage equipment0 ,plit system equipment

Pac&age e8uipment has all the components 1uilt into one ca1inet;hence= it is also called self0contained equipment. #ir is ducted to and from

the equipment.

/plit system 1 air conditioning the condenser is remote from theevaporator and uses interconnecting refrigerant lines.

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Ma_am Pabello_s PPT. Lesson BU2.pptx