Question

what is suction pressure

Answer 1

Suction pressure is what is generated when a negative difference in pressure is generated between two points which draws a gas or a liquid from a higher to a lower pressure region.

For example if the inlet pressure of a vacuum pump is at 900 mbar absolute and it is connected to a closed chamber at an atmospheric pressure of 1000 mbar absolute, the resulting suction pressure is -100 millibar gauge.

Answer 2

The actual pressure with which cell absorbs water is called "suction pressure". In refrigeration and air conditioning systems, the suction pressure' (also called the low-side pressure) is the intake pressure generated by the system compressor while operating.