Site Navigation Skip Navigation Links.
What is the "floating" condensing (head) pressure?
It is common knowledge in the industry that reducing condensing pressure saves compressor energy.

However, total condenser and compressor power usage is a function of two opposing effects. If the head pressure set point is increased, the condenser fans have to run less and savings in condenser fan's energy results.
On the other hand, increasing the head pressure set point increases the compressor discharge pressure and energy usage.
To run refrigeration plant efficiently, we have to keep total power usage (compressors + pumps + fans) at minimum.
Majority of the refrigeration plants have settings for condensing pressure around 150-160 psig.

This pressure is close to optimum during hot weather.
When the weather is getting cooler, optimum (the most efficient) condensing pressure is going down. Allowing this pressure to vary over a wide range (down to minimum possible value) can keep refrigeration plant at peak efficiency.
Sometimes readjustment of condenser fan pressure switches can reduce condensing pressure and save energy, but there is a point where additional fan's energy usage is equal to the savings gained from reduced condensing pressure, and therefore, any additional fans will waste energy.
During the cool weather, head pressure is usually higher than optimum value. Typical reasons for maintaining this pressure higher are hot gas defrosting, oil cooling, liquid supply, etc.
However, every barrier to lower condensing pressure has a solution.

Very often, right settings can reduce minimum condensing pressure and significantly improve efficiency of refrigeration plant.
From our experience, majority of the refrigeration plants can operate at minimum condensing pressure, lower then 100 psig, but each plant needs a different investment for that.

  © 2002-2017 SKEnergy.Ca.  Designed & Powered by © CSNet Inc.  All rights reserved.