Physical Principles
The four known states of water also apply to air conditioning system refrigerants.
When water is heated in a vessel (heat absorption), water vapor can be seen to rise. If the vapor is further heated through heat absorption, the visible vapor turns into invisible gas. The process is reversible. The warmth is extracted from gaseous water, vapor forms first, then water and then ice.
Heat Transfer
Every substance consists of a mass of moving molecules. The fast moving molecules of a warmer substance give off some of their energy to the cooler and thus slower molecules. As a result, the molecular motion of the warmer substance slows down and that of the colder substance is accelerated. This process continues until the molecules of both substances are moving at the same speed. They are then at the same temperature and no further heat exchange takes place.
Pressure and Boiling Point
The boiling point given in tables for a liquid is always referenced to an atmospheric pressure of 1 bar (14.5 psi). If the pressure acting on a fluid changes, its boiling point also changes.
For example, water boils at a lower temperature the lower the pressure.
The vapor pressure curves for water and refrigerant R134a show that, at constant pressure, reducing the temperature changes vapor to liquid (in the condenser) or that reducing the pressure causes the refrigerant to change from liquid to vapor (evaporator).
Vapor pressure curve of water
Vapor pressure curve of refrigerant R134a
Refrigerant R134a Vapor Pressure Table
The vapor pressure table for every refrigerant is published in literature for refrigeration system engineers. This table makes it possible to determine the vapor pressure acting on the column of liquid in a vessel if the temperature of the vessel is known.
Because each refrigerant has its own characteristic vapor pressure table, refrigerant can be identified by measuring the pressure and temperature.
Note
At absolute pressure, 0 bar/psi corresponds to absolute vacuum. Normal ambient pressure (positive pressure) corresponds to 1 bar (14.5 psi) absolute pressure. 0 pressure corresponds to an absolute pressure of 1 bar (14.5 psi) on most pressure gauges (indicated by -1 bar (-14.5 psi) below 0 bar/psi).
Temperature in ºC (ºF) | Pressure in bar (psi) of R134a |
-45 (-49) | -0.61 (-8.84) |
-40 (-40) | -0.49 (-7.10) |
-35 (-31) | -0.34 (-4.93) |
-30 (-22) | -0.16 (-2.32) |
-25 (-13) | 0.06 (0.87) |
-20 (-4) | 0.32 (4.64) |
-15 (5) | 0.63 (9.13) |
-10 (14) | 1.00 (14.5) |
-5 (23) | 1.43 (20.74) |
0 (32) | 1.92 (27.84) |
5 (41) | 2.49 (36.11) |
10 (50) | 3.13 (45.39) |
15 (59) | 3.90 (56.56) |
20 (68) | 4.70 (68.16) |
25 (77) | 5.63 (81.65) |
30 (86) | 6.70 (97.17) |
35 (95) | 7.83 (113.56) |
40 (104) | 9.10 (131.98) |
45 (113) | 10.54 (152.86) |
50 (122) | 12.11 (175.64) |
55 (131) | 13.83 (200.58) |
60 (140) | 15.72 (227.99) |
65 (149) | 17.79 (258.02) |
70 (158) | 20.05 (290.80) |
75 (167) | 22.52 (326.62) |
80 (176) | 25.21 (365.64) |
85 (185) | 28.14 (408.13) |
90 (194) | 31.34 (454.54) |
Volkswagen Tiguan Service and Repair Manual > Original Products: Cleaning Agent
Silicone Remover
Definition:
Silicone Remover -LSW 019 000 A5-, watery
Silicone Remover -LVM 020 000 A5-
Silicone Remover, Long -LVM 020 100 A5-
Silicone Remover -LSW 019 000 A5- Product Description
Silicone Remover -LSW 019 000 A5- is an unlabeled, watery cleaning agent that
has a low concent ...