Pump replacement is the time to exploit the best of modern technology
Energy consumption is 90% of the cost of a pump — Glynn Williams.
Glynn Williams is concerned that like-for-like pump replacement fails to exploit the benefits of modern pump technology.Like many industries which provide products that require an energy input to support their functionality, the pump industry in recent years has been very focused on accentuating the benefits to their specification base of energy-efficient solutions that place less strain on the environment and save money. Indeed, when you realise that over its lifespan the energy cost of the average pump in a commercial building services environment will account for around 90% of the total cost associated with the pump from the time of purchase to the time of disposal, this focus makes good sense. However, none of this takes into account the millions of pumps that are already in the commercial building stock and that frequently have a lifespan of 15+ years. When a pump needs to be replaced, the most frequent action is to buy an identical pump. Such a decision is rarely questioned — yet we would never consider buying the exact same car as we had 15 years previously or replace a washing machine with the same model we bought back in 1993 — because we would know there are be better/more efficient products available today. So why do we do it with pumps? Huge strides have been achieved in recent years in terms of the energy-efficient improve- ments that are now available from new generation pump technology products. Somehow, however, it is seen as being easier to reorder rather than to recalculate. So what other factors should be considered? Pump size
All circulators and booster pump applications were sized for an original duty of flow against a pressure. The first question to be asked is whether the pump is suitable for the current duty requirements, particularly if the building has undergone change. The pump may be over-sized and nameplate information may not reflect the original design duty or the current operating duty — and, hence, the replacement duty requirements. A review of the current system requirements will often lead to a more efficient pump selection, with the benefit of reduced energy consumption. Energy efficiency
Heating and cooling circulator pumps account for most of the replacement market. The market today favours the use of glandless circulators for heating applications because of their compact nature and low maintenance demands. Glanded products with mechanical seals are more efficient, however, and can be fitted as direct replacements for glandless circulators in some cases. Where conventional motors are used, these should also be EFF1 or better. Some manufacturers, like Grundfos, offer such motors as standard for fixed-speed solutions. For variable-volume systems, permanent-magnet circulators are often today’s preferred choice (like the Magna family from Grundfos) as they can deliver significant energy savings over older style pumps by self adjusting to the demands of the system. Service needs
Analysing the energy used by the pumps in a building-services installation identifies what changes should be made and the savings to be achieved.
With glandless circulators, the replacement heads are readily available and are simple to change. On glanded pumps the two main service items are the motor and the mechanical seal. Today’s pump designs facilitate easier replacement of components that wear. The choice of a major manufacturer which can provide service for the long term is important, as they will have a wide range of dedicated service kits and replacement motors available. Pipework modifications
With space at more of a premium than it was 15 years ago, the choice of in-line or end-suction style products is important. For example, access to the motor is important, so sufficient space needs to be allowed for instances where cranes or hoists may need to be used. Timing
Ideally, the time when a pump is replaced should be planned — for example, replacing heating stock in the summer. However, emergencies do occur, and it is then important to ensure you are getting the best longer-term solution but with readily available stock. This is where reputable pump manufacturers will be able to advise and assist with the best technical solution. Help is at hand
To assist in making the decision as painless as possible Grundfos has developed tools that help make the replacement process easier with the on-line replacement pump selection tool called WebCAPS (visit www.grundfos.com) and a CD selection tool called WinCAPS. When the ‘Replacement’ option is selected from either the web site or the CD, the user is invited to input a number of key pieces of information —including the current pump type and if the replacement decision is to be based on energy cost considerations. The program will then calculate the energy and cost savings that can be made by opting for a better efficiency pump, thus taking all the guesswork out of the replacement equation. Grundfos also offers customers a complete energy audit, with an audit tool fitted into a customer’s system to analyse how much energy is used by the pumps. A report is then completed advising what changes should be made and the savings these would realise. What will you be doing in 2023? None of us knows with certainty what we might be doing in 15 years’ time when it will be 2023. We know that there will be many changes between now and then in all industries, but we are sure that the same principle will prevail — make the best choice you can today as it will help make the world a better place tomorrow. Glynn Williams is director of sales for commercial building services with Grundfos Pumps.
In variable-volume systems, pumps such as those from the Grundfos Magna range can use up to 80% less energy than fixed-speed pumps.