What is suction pressure and discharge pressure?

Answer 1

Answer: The terms suction and discharge are the terms refer to hydraulics. In hydraulics if the the liquid has to be lifted or pumped to the usage area the hydraulic pump will be used . This pump will have to functions that is first suction to lift the fluid and the discharge or delivery . The familiar words in pair are lift and discharge; suction and discharge. The specification of pump for these terms are suction head and discharge head.Answer

The suction pressure refers to the pressure of the referigerant being "sucked" back into the compressor. The suction pressure is a critical variable in ensuring the accuracy of the refrigerant charge, along with the tepmerature of that line as well. The "superheat", or heat added to the vapor in that line can be monitored in this manner.

You have not mention which suction pressure... Actually Where ever the suction is presented that pressure is called suction pressure.... and suction pressure in practical cases normally always less that atmospheric pressure and in case of delivery pressure it is opposite

Saying that suction pressure is " the pressure of the referigerant being "sucked" back into the compressor " is not accurate.

Simply , the suction pressure of a pump is the absolute pressure of a fluid , measured at the inlet of the pump ( in your answer , the pump is the compressor , and the fluid is whatever refrigerant. )

The discharge pressure , is the absolute pressure of the liquid measured at the outlet of the pump.

Obviously, the discharge pressure is usually bigger than suction pressure.