The pipework system determines the choice of the pump performance. Indeed, its characteristics have to be combined with those of the pumps to obtain the required performance of the pumping installation as shown in the Figure 3.37 below.
The energy consumption directly connected to the piping system is the consequence of the friction loss on the liquid being moved, in pipes, valves, and other equipment in the system. This loss is proportional to the square of the flowrate. Friction loss can be minimised by means such as:
●avoiding the use of too many valves
●avoiding the use of too many bends (especially tight bends) in the piping system
●ensuring the pipework diameter is not too small.
The applicability of particular measures, and the extent of cost savings depend upon the size and specific nature of the installation and system. Only an assessment of a system and the installation needs can determine which measures provide the correct cost-benefit. This could be done by a qualified pumping system service provider or by qualified in-house engineering staff.
The assessment conclusions will identify the measures that are applicable to a system, and will include an estimate of the savings, the cost of the measure, as well as the payback time.
Pumping systems often have a lifespan of 15 to 20 years, so a consideration of lifetime costs against initial (purchase) costs are important.
Pumps are typically purchased as individual components, although they provide a service only when operating as part of the system, so a consideration of the system is important to enable a proper assessment of the cost-benefit.
Energy Efficiency (2009) 3.8.3