MOLLIER Diagrams

P-h CHART

PRESSURE ENTHALPY CHART

WHY IN REFRIGERATION?

• To determine accurately what is going on inside a refrigeration system

• Visualize the refrigerant behavior• Calculating capacities of refrigeration

system• Representing the condition of

equipment at any thermodynamic state.• TROUBLESHOOTING…

Classic Refrigeration system

Refrigerant regions

Constant pressure line

Constant temperature line

Enthalpy line

Constant specific volume line

Entropy line

How to plot a P-h chart?

Data From the Unit

• Low pressure P1=3 bar• High pressure P2=14 bar• Suction temperature T1=0°C• Discharge temperature T2=70 °C• Condensing temperature T3=40 °C• Temperature at TXV T4=10 °C• Evaporating temperature T5=-6 °C

P1

P2

T1

T2

T3

T4

T4

Enthalpy

Superheat

Sub cooled

High head

• Recycle cooling medium

• High cooling medium

• Poor cooling medium flow

• Fouled condenser• Non-condensable

Over charge

Low charge

• System leak• System incorrectly

charged

Liquid line restriction

• Filter dryer chocked• Blocked particle

inside the system

Poor Compressor

• Under sized compressor

• Unloaded compressor• Wrong compressor

pulley sizes• Bad compressor

valves, ring or pistons

MOLLIER Calculation• Compression ratio=High pressure/Low pressure• Flash gas=(h4-h4’)/(h1-h4’)• Refrigerating effect=h1-h4• Circulation rate of refrigerant=Refrigerating

capacity/refrigerating effect• Power at compressor=circulation rate x (h2-h1)• COP=Refrigerating capacity/power at compressor

MOTORSINGLE PHASE

SINGLE PHASE MOTOR

SINGLE PHASE MOTOR

SINGLE PHASE MOTOR

SINGLE PHASE MOTOR

SINGLE PHASE MOTOR-testing

SINGLE PHASE MOTOR-testing

SINGLE PHASE MOTOR-testing

SINGLE PHASE MOTOR-testing

SINGLE PHASE MOTOR-testing

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

• Run (operating) - large dimension, low capacitance 30F

• Starting - small dimension, large capacitance (can

exceed 100 F)- 5 seconds, 20

start- ups/hour

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

SINGLE PHASE MOTOR-capacitor

• 240V, 2A

• Xc =240/2, = 120• C =1/(2**Hz*Xc) = 1/(6.28*50*120)

= 0.00002652 F

= 26.52 F

SINGLE PHASE MOTOR-capacitor

• Normally 14 times of Amperage

• 2*14 = 28 F, if 10% 30.8 F or 25.2 F

• If out of range; change capacitor

THREE PHASE MOTOR- general point

THREE PHASE MOTOR- general point

• P =3*V*I*=1.732*220*1.7*0.8 = 520W

=1.732*380*1*0.8 = 520W

THREE PHASE MOTOR- general point

THREE PHASE MOTOR- general point

• 145W loss as heat• 375W/520W= 0.72

• 72% useful• 28% loss

THREE PHASE MOTOR- general point

THREE PHASE MOTOR- general point

THREE PHASE MOTOR- delta

THREE PHASE MOTOR- delta

THREE PHASE MOTOR- star Y

THREE PHASE MOTOR- star Y

THREE PHASE MOTOR- ?

THREE PHASE MOTOR- connections

Protection DevicesProtection Devices

THERMAL OVERLOAD RELAYS

FUSE FOR DISTRIBUTION

FUSE FOR MOTORS

Thermal RelayThermal Relay

Combination of a thermal overload relay with a contactor

Electromagnetic Overcurrent Relay

Electromagnetic Overcurrent Relay

Contactor - BreakerContactor - Breaker

Isolator - BreakerIsolator - Breaker

COMBINATIONS OF PROTECTION DEVICES

COMBINATIONS OF PROTECTION DEVICES

COMBINATIONS OF PROTECTION DEVICES

COMBINATIONS OF PROTECTION DEVICES

COMBINATIONS OF PROTECTION DEVICES

COMBINATIONS OF PROTECTION DEVICES

SWITCHESSWITCHES

• Manual switch-on pushbutton

• Manual switch-off pushbutton

• Manual on-off pushbutton

S1

S2

S3

SWITCHESSWITCHES

• Emergency stop pushbutton

• Color: Red – large mushroom head pushbutton

Limit switches Limit switches

• Normally open contact • Operated by mechanical sensor (cam roller)

• Normally open contact • Operated by level

• Normally open contact • Operated by temperature

• Normally closed contact • Operated by pressure

•

S11

S11

S11

S11

S11

P

Other switches Other switches

• Normally open contact • Operated by electromagnetic • Operating equipment designation: KM (contactor); KA

(relay)

A1

A2

KM1KM1

11

14

ELECTRICAL DIAGRAMS & WIRING

ELECTRICAL DIAGRAMS & WIRING

DIRECT ON LINE (D.O.L.)DIRECT ON LINE (D.O.L.)

• -The stator connected directly to the main supply

• -The motor starts with a high peak

• -Current peak 4 to 8 times of rated current

• -1 to 5 hp

D.O.L.D.O.L.

• Main circuit

D.O.L.D.O.L.

• Control circuit

D.O.L… forward reverse D.O.L… forward reverse

• Main circuit wiring diagram

M

L1

L2

L3

F1

KM1

A1

A2

KM2A1

A2

U1 V1 W1

F2

X11

2

3

X2

D.O.L… forward reverseD.O.L… forward reverse

• Control circuit wiring diagram

KM1 KM2

F1L1

S1

S21

S31

N

KM11

KM2

KM2 KM1

D.O.L..block diagramD.O.L..block diagram

STAR DELTA (YΔ)STAR DELTA (YΔ)

• -Motor having both ends of the three stator brought out-6 terminal

• -First step with Star- (main voltage/√3)

• -Second step with delta-normal voltage

STAR DELTA (YΔ)..power circuit

STAR DELTA (YΔ)..power circuit

STAR DELTA (YΔ).. Reverse rotation

STAR DELTA (YΔ).. Reverse rotation

STAR DELTA (YΔ)..control circuit

STAR DELTA (YΔ)..TNB control circuitSTAR DELTA (YΔ)..TNB control circuit

STAR DELTA (YΔ)..TNB power circuit

AUTO TRANSFORMER..control circuit

AUTO TRANSFORMER..control circuit

AUTO TRANSFORMER..Power circuitAUTO TRANSFORMER..Power circuit

SPECIFICATION

POWER SUPPLY

POWER SUPPLY

Connection - fan

Connection - condensing

Connection - condensing

Connection - condensing

That had been…

AC Technology

ZULKARNAINI ABDULLAHzulkarnaini@mfi.unikl.edu.myzulkarnaini_a@hotmail.com012 913 8059