| There must be space both for liquid and vapour in a
container. As the temperature rises, the liquid expands. The
space occupied by the vapour becomes smaller. Eventually, there
will only be liquid in the container. After that time, even a
small increase in temperature will result in a very large
increase in pressure, since the liquid is seeking to expand
further but there is no space for it to do so. The resulting
forces are sufficient to burst the container. To prevent
containers from being overcharged, regulations governing the
storage of compressed gases specify how many kilograms may be
charged into a container for every litre of container volume.
This charge factor multiplied by the internal volume gives the
permissible charge quantity. The charge factor for the
refrigerants used in cars is 1.15 kg/l. |
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Questions & answers
Charge factor — Volkswagen Golf Mk7
What is the charge factor for R134a containers?
Containers must not be completely filled with liquid — space must be left for vapour expansion as temperature rises. The manual specifies safe fill ratios.
Only very small amounts of water are soluble in liquid
refrigerant. On the other hand, refrigerant vapour and water
vapour mix in any proportion.
...
External damage can cause leaks in the refrigerant circuit. Because a small
leak will involve only small quantities of refrigerant, leaks should be checked
for using an electronic leak detector or ...
