Air Cond

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The Air conditioning System
Expansion valve

Compressor

Blower

Evaporator Fan Condenser Drier

Air conditioning systems

Advantages: Cooling the air /Comfort/safety Dry air Clean air

Components of air condition

1. 2. 3. 4. 5. 6. 7.

Compressor Condenser and Fan Pressure control switch Reciever / Drier Expansion valve Evaporator Heat exchanger

8.

Blower

Physical and technical law of air conditioning
What is cooling?
Cooling is the transport of heat energy from a place we don`t want to have to a place where it is no problem

Possibilitys:
Latent heat of evaporation-----------------------------------Latent heat of condensation

Cold air inside 10°C for example 35°C ice

0°C

0°C
liquid

Warm ambient air 35°C for example

-30°C

Boiling temperature and pressure of water

Boiling temperature of water in °C

presure in bar (absolut

151 100 68 12,7 6,7

5 1 0,3 0,015 0,010

Condensation of water

vapor Air
100°C Water Water

Refrigerant R 134
pressure in bar boiling temperature in °C

0

-26,5

1

-9

2

+2

3

+11

4

+18

5

+25

6

+31

Evaporation

+ 10°C

- 9°C

16 bar
7 bar R 1 bar

A + 27°C R134a - 9°C + 27°C

B

- 20°C vapor

40°C Still liquid

Ice cold

liquid

vapour liquid cold - warm vapour

vapour

Ice cold

hot

liquid

warm

Refrigerant and Ozon Stratosphare 15 – 60 km

Refrigerant and green house effect

Green house potential

Cars

3 up to 16 hp

Busses

up to 50 hp

Cutaway of typical swash plate piston compressor (double side working Pistons)
1. 2. 3. Shaft Swash plate Double piston

4.
5.

Valve plates
Magnetic clutch

Cutaway of typical swash plate piston compressor (single side working Pistons)

Variable displacement compressor Control Valve
bellows Chamber pressure

High pressure

low pressure

1) control valve 2) regulation pressure 3) sliding shaft

4) spring 5) throttle bore

Rotary vane compressor

Scroll type compressor

Refrigerant oil
Compressor

Condenser

Drier

Evaporator

Hoses Drier Hose 15 ccm/ml

5 ccm/ml/m
40 ccm/ml 40 ccm/ml

Refrigerant oil wich is taken from the system during discharging must be filled into the system after vacuum.

Evaporator Condenser

also when system components are replaced we have to fill oil into the system

Accident 50 ccm/ml suddenly discharged

Electro-magnetic clutch

1 Fixing screw 2 Disk 3 Front plate 4 Rotor assembly

Condenser

Problems:
•Dirty •Leaking •Corrosion •Fan vapor insects / flies stones inside / outside out of order liquid

Reciever / Drier

Funktion / Purpose
•To act as drier for the refrigerant •To act as filter for the refrigerant •To act as reservoir for the refrigerant •Change gas bubbles to liquid

•Damper for refrigerant vibrations
•Contains the sight glass

Important:
Drier has to be changed, when the sytem has been open or leaking for more then 5 minutes Drier should be changed every two years

1) from Condenser 2) sight glass 3) Outlet

4) Drying element
5) Liquid refrigerant 6) Pipe 7) Compensation chamber

Thermostatic expansion valve
Needle

Sensor / stretch element

Diaphragm

To compressor (vapor)

From drier (liquid)

Needle down more open

Ball valve

Spring

PFÜ
Pressure on top of the diaphragm tends to open the valve dependent from temperature of stretch sensor

PSA
Refrigerant pressure under the Diaphragm high pressure tends to close the valve

PFE
Spring power

Evaporator

Problems:
•Dust particles •Pollen

•Mushrooms

Expansion valve (Block type)

Ambient air Temperature mixture flap Heat exchanger

Wind screen

Blower Evaporator Foot compartment

Dashboard

Orrifice tube

Accumulator Drier
Refrigerant vapour from evaporator

Refrigerant vapour to compressor

Low pressure switch

„U“ Tube Capillary to refrigerant tube Drying element

Filter screen

Filter

Lubricant

Thermostat
Switch point adjustable (possible) Controls compressor clutch Wrong Adjustment •Evaporator frozen •Bad cooling

Evaporator temperatur sensor

Pressure control switches

Switch off pressure: About 2.0 bar (in HP) About 1.0 bar (in LP) Not enough refigerant inside system About 30 bar Always installed in HP Pressure in sytem to high

1. 2.

HP switch LP switch

3.

Switch on the second stage of condenser fan at about 18 bar

Electrical circuit with double pressure switch

Line 15 Main switch HP/LP switch Termostat

Magnetic clutch

Pressure switch check

Pressure sensor
Always installed in HP side
Signal to ECU Never install a bridge

Pressure about 2.0 bar Plus supply from ECU
PWM Signal Microprocessor
Periode

Puls wide

Pressure about 30 bar
Periode

Voltage Signalvoltage Siliciumresistor

Puls wide

Electrical circuit
Typical electrical circuit for air conditioning system without electronical control

Number B015

component Blower

B043
B159 C526 C588 D621 D744 E027 E031 E136 E508 E509 E557

Compressor
Condenser fan A/C switch Blower switch Diode Diode Fuse Fuse Fuse Thermostat High/Low pressure switch Condenser fan switch

G065
G150 G151 Information

Blower relay
Compresor relay Condenser fan relay

E509 and E557 are placed in one housing.

Air conditioning system including two Evaporators, expansion valve and fixed orifice tube

liquid vapour

1. 2. 3. 4. 5. 6.

Condenser Trinary switch Orrifice tube Evaporator front Accumulator Low pressure switch 7. 8. 9. Evaporator rear Expansion valve Compressor

Vacuum in air conditioning system
Moisture in air conditioning systems

System frozen inside

Water = Corrosion

Water

and

Refrigerant = Acid

Steel

Copper
Brass Water and Refrigerant and Heat = more Acid

Boiling temperature and pressure

Minimum 30 Minutes

Vapor

Water

Checking air conditioning system
Conditions:
•System working 5 Minutes in high idle speed •Blower step 1

•Maximum cooling
•Air outlet only at the middle Grid

Outside – Temperatur °C 15

Vapor side, bar 1,50 – 2,00

Liquid side, bar 5,0 – 13,0

Temperatur at middle air outlet grid °C 3–6

20
26 32 37

1,50 – 2,20
1,80 – 2,30 2,10 – 2,35 2,30 – 2,50

6,0 – 13,0
7,0 – 14,5 8,0 – 18,0 10,0 – 20,5

3–6
3–7 4–8 5 – 10

At special systems may be differences

All informations only for systems working with ordinary Compressor

Air condition equipment

Leak detection

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