What is pump efficiency formula?
There is no formula. Pump manufacturers test their pump by measuring at any given speed through the head (pressure) and volume range the amount of power consumed and compare this with the theoretical power required. This efficiency is not constant throughout the range. Generally manufacturers do not provide these efficiency points but do publish the expected power curve for any given pump speed.
In this multi-part series, we will investigate several aspects of centrifugal pump efficiency. First, I will define efficiency and give some examples. Next, I will examine some of the design criteria that ultimately dictate the efficiency exhibited by a particular pump.
Head = 160 feet. We measured it at the discharge side of the pump and corrected it for the fact that the gage was two feet above the pump center line. Look at the following diagram where we have calculated the discharge head from the formula shown on the right hand side of the illustration. If there were any positive head on the suction side of the pump that head would have to be subtracted. A negative suction head would be added to the discharge head.
Main principles of pumps selection
Capacity (delivery, flow rate) – volume of medium pumped by a pump per unit of time. It is denoted by letter Q and has dimension in m3-h, l-s, etc. Flow rate quantity includes only factual volume of displaced fluid ignoring return leakages. The theoretical and factual flow rate ratio is expressed by volumetric efficiency quantity:
Theobald serves as an active consultant for industries looking to achieve and maintain improved wastewater treatment at reduced cost. He is a Lifetime Member of the Who’s Who Registry of Professionals and holds numerous certifications from wastewater management regulatory boards and professional organizations. Theobald contributed one chapter to the Water Environment Federation’s (www.wef.org) Manual of Practice # 37 (MOP-37), a technical manual resource guide for biological nutrient removal, published in 2013.
Power is consumed by a pump, fan or compressor in order to move and increase the pressure of a fluid. The power requirement of the pump depends on a number of factors including the pump and motor efficiency, the differential pressure and the fluid density, viscosity and flow rate. This article provides relationships to determine the required pump power.
For a pump that has been already purchased or has been ordered for manufacturing, the efficiency can be determined using the pump performance curves provided by pump manufacturer. Here the problem statement has specified pump efficiency to be 70%.
How to Calculate Coefficient of Performance
Efficiency is how much energy you get out of an appliance, compared to how much energy you put into running it. A 97% efficient furnace gives you back 97% of the energy you put into it in the form of heat for your home, the other 3% is lost up the flue. Since electric baseboard has no flue, 100% of the energy that goes in, stays in your home in the form of heat. The higher the efficiency of your system, the lower your heating bills.