PUMPS, WASTE MANAGEMENT & WATER TREATMENT


Optimising pump systems for improved efficiency


P


Given the global rise in energy costs, there has never been a better time to review and assess the efficiency of your pumping systems – whatever their size, complexity or indeed area of operation. Gary Wilde, technical services officer at the British Pump Manufacturers Association (BPMA) offers some insight


ump systems account for 20% of the worlds electrical energy demand and between 25% - 50% of the electrical energy usage in certain applications. Pumps are the single largest user of electricity


within industry across the European Union, consuming over 300 TWhpa of electricity, which in turn accounts for over 65 Mton of CO₂ emissions.


It is also well documented that


rotodynamic pumps which account for 80% of the installed base are between 20- 30% oversized. There is therefore a major potential to save energy if rotodynamic pumps are properly sized and operated.


Where to start - Assess the potential for savings


Understand your pumping system: To identify if a pumping system is sized correctly make the following checks;


• Are you wasting liquid flow? • Are you creating additional pressure? • What is the monitoring & controls philosophy?


• Are there any oversized pumps installed for your required duty?


• Are there any old pumps employed in the system?


• Is there excessive noise in the system? • Are there any throttling valves installed in the system?


• Have you the correct size of pipework installed?


• Inadequate maintenance lowers pump system efficiency, so what maintenance procedures are in place?


• Are you adopting a proactive equipment replacement programme to current EU legislation


energy use Has an alternative configuration been considered?


Key considerations to optimise


In some cases, moving from an existing pump layout to an alternative can offer energy saving possibilities.


Is the Pump Performance Monitored? By looking for early signs of pump wear which can include increased noise, vibration or power consumption, major energy and


Variable Speed Drive Considerations


When fitting VSD to a pumping system, output and input filters should be considered, along with insulated motor bearings.


Maintenance


When maintaining pumping systems it is recommended to use original manufacturers’ recommendations and parts.


Reliability / Security


Efficient, well-maintained pumps are more likely to be reliable and unlikely to fail prematurely causing loss of production or services.


Valves Valves are considered to waste energy within a pumping system, however if installed they should be checked for correct operation.


Pumps not in use


Stand by pump units or pumps with no demand should be switched off to save energy.


Is the pump working most of the time close to its best efficiency point? Rotodynamic pumps operating away from BEP not only waste energy, but also reduce the life expectancy of the pump.


System Alterations


When upgrading, changing, or expanding a pumping system the demand may have changed and existing pumps may not be the most efficient solution.


Purchasing the correct pump set When purchasing a pump set, price should not be the deciding factor. If a pump is sized correctly the return on investment is shorter, likewise if a pump is oversized and is wasting energy going forward you will have this additional cost for the anticipated life of the pump set.


Has an energy check been undertaken on existing systems? Under UK ESOS regulation all non-SME organizations are mandated to carry out energy audits, and pumping systems can offer substantial energy savings.


When specifying a new pump, ask for a high efficiency motor to be fitted. If you are replacing or rewinding a motor, then evaluate the cost of fitting a High Efficiency motor remembering to factor in the running savings which will pay back any increase in cost. Invest in carrying out an energy audit. Review your utility bills and understand the energy you are using. Carry out an audit if:


• Your energy bills are high • You have continuously operating pumps • You have many pumps in the system • You have processes with varying flows • You have throttled pumps • You have pumps which are on bypass • You have noisy valves or pipework • You have critical systems which have been subject to breakdowns


Read the latest at: www.bsee.co.uk


The purpose of an energy audit is to reduce operating costs by reducing energy consumption and the government has estimated that most companies can reduce their energy consumption by 10% to 20%. Energy audits conducted by BPMA members have shown that savings from 30% to 50% are not unusual. When deciding whether or not to carry out an energy audit a good starting point is to assume that you will save at least 10% of your current energy consumption. By reviewing utility bills, you can get an indication of the savings to be made and the investment that you should be prepared to put into the auditing process. Across most industrial sites, some two-


thirds of the total energy consumption is used to power electric motors. Furthermore, the overall cost associated with operating these essential pieces of equipment throughout their entire life span can be broken down as follows; 5% accounts for the initial purchase/installation costs, 10% for ongoing maintenance and a massive 85% for the energy used to run them. Clearly, any reduction in the energy consumed by electric motors is important, and with modern designs that reduction can be as much as 30%. It is also evident that many pumps and motors are constantly operated at full power, irrespective of process needs, and so across the installed base there is the potential for significant energy savings; savings which can in turn drop to the bottom line and increase the profitability of any business.


BPMA involvement


Given the amount of energy consumed by pumps through their normal operation, and the potential for energy efficiency gains within pump systems, the BPMA have worked to develop a Certified Pump System Auditor Scheme (CPSA). Through the CPSA, pump engineers are being trained to correctly assess the efficiency of pump systems, and to provide appropriate recommendations in order to improve the efficiency of those systems. The CPSA accreditation is achieved by successfully completing a four-day residential course, followed by the satisfactory completion of a pump system audit. Only then can ‘Certified Pump System Auditor’ status be achieved. Within the full ESOS Guidance document, the ISO/14414-Pump System Energy Assessment standard is referenced as an auditing methodology that can be accepted by “Lead Assessors” approved by the Environment Agency. Accordingly, it is hoped that CPSA accredited persons (who are trained according to the IS0 14414 standard) will be recommended by Lead Assessors to undertake the pumping system elements of company- wide energy audits.


maintenance savings can be achieved.


Has ease of maintenance been allowed for? When designing or replacing pumps, ease of future maintenance requirements should be considered.


BUILDING SERVICES & ENVIRONMENTAL ENGINEER DECEMBER 2022 21


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36