Saving energy in 2006 is a no-brainer. Even if you're not the tree-hugging type, the barrage of dire climate change warnings is enough to penetrate all but the thickest of skins.
And if profit is your priority, energy prices are on a rocket-propelled rise that shows no sign of stopping.
So you've switched to energy saving light bulbs and turned the heating down, but what else are you going to do? Reviewing your pumping operations could be a surprisingly rewarding next step.
Pumping systems account for nearly 20% of the world's electricity demand and between 25% and 50% of the energy consumed by many industrial sites, according to the Europump trade association. Typical food businesses are likely to be at the lower end of this energy-use spectrum, but their pumping costs are still significant.
"In the water industry over 10% of their operating costs are for pumping. In the food industry it's still an issue but people don't pay enough attention to it," says Maurice Yates, founding director of Advanced Energy Monitoring Systems (AEMS). AEMS is a consultancy and equipment supplier based in Devon.
Difficult media
According to Yates, the difficult media often encountered in the food industry is one reason why manufacturers have been slow to adopt energy efficient pumping.
"The problem is that the first job is to pump whatever you've got to pump and efficiency simply isn't the top priority," he says.
The capital cost of some of the specialist pumps needed in the food industry is also relatively high in relation to the energy they use. For example, it may take just one month for a typical pump in the water industry to use energy equivalent to its initial cost but it will take considerably longer for a specialist food pump to run up an energy bill to match its price tag.
For this reason, Alun Davies, industrial director for pump manufacturer Grundfos, says that it's helpful to distinguish between process and non-process pumps when looking for energy-saving opportunities in food production.
"The biggest area for saving energy in the food industry is on the utility side, where they're using water as the feed for a steam boiler, for example." So, while sticky, lumpy, abrasive or delicate foodstuffs may leave manufacturers with few pumping options, the water used for heating, cooling and cleaning could prove to be a valuable source of potential savings.
Davies estimates that over 80% of the cost of a pump over its lifetime is operating costs. Europump goes even further, estimating that 90% of the cost of owning almost any pump is its energy consumption.
And even more promising for energy-saving initiatives, Europump also cites studies that have shown that between 30% and 50% of that energy could be saved by making a few changes.
Keep your cool
The thermodynamic efficiency of a pump is a measure of the 'work out' to 'work in', with the rest of the energy lost as heat. The aim is to get pumps working as close as possible to their optimum efficiency, although that optimum will vary depending on the type of pump.
For example, a progressing cavity pump may have an optimum thermodynamic efficiency of, say, only 20%. That 20% then becomes the 100% you're working towards.
One of the services offered by AEMS is to measure thermodynamic efficiency by taking the temperature of the pumped medium before and after the pump.
"The concept is very easy, but the temperature difference is only a few thousandths of a degree Centigrade," says Yates. "When I first started doing this, people didn't believe it was possible."
While the Yatesmeter is now a well-proven tool, Yates points out that energy efficient pumping is often as much about common sense as it is about thermodynamics.
It's not rocket science
"The first thing to look at is whether you're pumping when you don't need to," he says. "I once told an engineer that a pump was costing him £75 an hour to run. He went straight over and turned it off. I asked him why he did that and he said they didn't even need it on. It's not rocket science."
The next thing to watch is the condition of the pump. Yates estimates that a pump can lose around 20% of its efficiency before it becomes obvious that something is wrong: "Pumps will carry on pumping without letting you know if they are compromised, for example, by screaming or vibrating."
The third leg of the common sense approach is choosing the right pump for the right duty. "The main thing is to make the pressure and flow match the requirement of the system, rather than just saying that we had a 3kW pump in before so let's get another one," says Yates.
"Pumps can run anywhere between 10% and 90% efficient and the key is to match the duty so that they operate at the optimum point on the pump curve."
A matter of speed
Modern equipment also has a role to play. According to Davies, the two most important technologies are variable speed drives (VSDs) - which control the pump's motor to match the pumping speed to the required duty - and energy-efficient motors.
Coca-Cola Enterprises (CCE) has been fitting VSDs to pumps throughout its six UK sites since 2001, as part of the company's wider energy-saving initiative. The current programme at the Sidcup factory is a good example, where CCE is replacing three 37kW fixed-speed pumps with four 11kW pumps fitted with VSDs. This investment is expected to save over £15,000 in energy, or 300,000kW per year. "To put it another way, it's the electricity to supply an average house for over 90 years," CCE said.
Everyone agrees that VSDs have an enormous role to play, but Yates sounds a note of caution: "In the right application they are very, very good, but you have to know what you're doing. For instance, an operator may turn the pump speed down to very slow and may not generate enough pressure to move the fluid out into the system. That could make the pump overheat."
"Proper training is the answer. We've been working with a client where we've recently managed to raise their pumping efficiency from 69% to 82% with proper training and improved controls," he adds.
Motor magic
In terms of motors, there is now a quick way to gauge how different models compare in terms of energy consumption. For AC motors between 1.1 and 90kW, the EU now requires manufacturers to label motors according to efficiency. The labels run from EFF3 (the least efficient) to EFF1 (the most efficient).
The difference in efficiency between a high-efficiency EFF1 motor and a standard EFF2 motor can be as high as 6%. This can offset the additional cost of an efficient motor compared to an EFF2 motor in 18 to 24 months and the EFF1 model will continue to save energy and money over the life of the equipment.
Better still, the cost differential for end users opting for EFF1 motors is coming down. Grundfos, for example, already fits its most popular industrial pumps with EFF1 motors as standard, without charging a premium. "We started with our CR industrial range at the beginning of the year and the intention is to gradually harmonise our products by uprating to EFF1 motors throughout," says Davies.
The stakes for European industry are high. It has been estimated by officials from the EU's Motor Challenge Programme that replacing all the EFF3 motors now in use across Europe with EFF2 versions would yield energy savings of 6TWh, or euro 300M a year. FM
To pump ... or not to pump
Even though difficult-to-pump media make it harder for food processors to make energy efficiency the priority, pumping may still be an energy-saving option compared with the alternatives. US-based chicken processor George's cut its energy bill by $17,000 a year by switching from a vacuum-based transport system to a progressive cavity pump at its Springdale facility.
The system moves dead-on-arrival (DOA) chickens from the production area to the offal building some 120m away.
The pump was supplied by Seepex with a 5HP motor, compared to the 25HP motor used to drive the vacuum system. In addition, the vacuum system ran 24h a day, while the pump only runs for about two hours. The DOA birds are transferred in batches during routine work breaks.
KEY CONTACTS
- Advanced Energy Monitoring Systems 01404 812294
- Europump 0032 2 706 8230
- Grundfos 01525 850000
- Seepex UK 01935 472376