PACIFIC Wood Products recently fitted two Ecogate dust extraction control systems in its Napier factory.

The Ecogate system suits businesses where there are several machines connected to a central extraction system and diversity across the machines. The system monitors the extract requirements of individual machines, then automatically optimises extraction availability and modifies the dust extractor’s fan speed to suit demand.

This facilitates optimum dust extraction supply and energy consumption for the business that invested in the system. For Pacific Wood Products it resulted in a leaner power account. In the four months one of the systems has been in use, the company has been getting a cost saving on average load of close to 50 percent in its pine remanufacturing plant, according to Pacific Wood Products (PWP) chief executive Tony Clifford.

Clifford says PWP management are always looking for ways to work smarter. Smarter includes both managing the company’s environmental footprint and operational costs. “Energy in New Zealand is getting more expensive all the time. So it makes sense to save wherever we can, and we’re in constant dialogue with our energy provider, Contact Energy, about ways to optimise our electricity consumption and peak demand and consequently lower our bill,” he says.

Contact Energy introduced PWP to the Ecogate concept last year. So why is the system so well suited to PWP’s operation and how does it work?

PWP is a subsidiary of Pan Pac Forest Products, which owns and manages 33,000 hectares of pinus radiata forests in New Zealand. PWP’s lumber input is made up of 70 percent high grade, 15 percent tight knot grade, and five percent knotty grade products.

The company has an established history of providing feedstock for local and offshore markets. In recent years it has also steadily integrated processes to the point where it now produces and markets its own line of remanufactured pine products.

The product lineup includes untreated Clearboard™ for interior projects, Paint Grade Contour Exterior™, and Contour Interior™ moulded product from the high grade lumber; cavity battens from the tight knot grade lumber; and door cores from the knotty grade lumber.

The 1300 square metre Napier plant operates three sawing lines, three planer lines, a finger jointing line, several laminating lines, and a sanding line. The processing machines are batch operations and essentially work in parallel. Two dust extract systems totalling 165 kilowatt of connected load services the processing plant. The one system, operating with a 90kW fan, services nine machines. The other extraction system, operating with a 75kW fan, services seven machines. 

Before the Ecogate system came on line, both extraction units had habitually run at full load all the shift hours, regardless of the number of actual manufacturing machines in use. This had become an area of concern for PWP, which the company shared with Contact Energy customer relations manager Ross Berry.

Says Clifford: “We had a manual damper gate on the sander line, which we used infrequently. However, the system requires a minimum number of ducts to be open to prevent collapse of the ducting and to maintain minimum flow in the ducts. A manual damper gate approach across the whole extract network cannot be managed manually.”

The logical answer was to put in an automatic system to monitor what machines needed extract and control the duct opening and fan speed to suit this demand. Simple enough, but there was no integrated technology package available in New Zealand to do this at the time.

PWP, however, was not the only company wanting to deal with this issue. Following an audit Berry did at a kitchen joinery factory in Auckland in August 2008, he began doing research in earnest to find a solution to eliminate unproductive kilowatt hours. His research led to the Ecogate website, and he shared this with PWP as a possible avenue to address the matter.

A good track record

Berry started a full scale due diligence on the Ecogate product.

“To install a system means downtime for a business. Any downtime means losing money, especially in the PWP factory, which is very busy. It was important to get something that delivered what it promised first time round, something that would be simple to install, simple to maintain, and would avoid major disruptions to production schedules,” he says.

As part of his research, Berry visited the Ecogate factory in California for product information and training. The product has been in use in the US for the past decade and Ecogate customers include the US Navy; electric guitar maker Fender; and RSI, a flat pack kitchen cabinet manufacturer.

Berry saw the system in operation in several customer plants. “Once I realised how long it had been around, saw it in action, talked to customers, I was ready to go with it. All the figures I’ve come across indicated Ecogate was indeed getting the kind of results it was mentioning in its marketing material. These results vary from site to site, depending on the operating profile of the business, but can be as much as a 68 percent saving on power consumption,” he says.

On Berry’s advice PWP successfully applied to the Energy Efficiency and Conservation Authority (EECA) for a technology grant to assist with the costs. In January 2009, PWP became the second company in New Zealand to install the technology on the bigger of its two dust extraction systems, with the second system installed in April.

A kitchen cabinet factory in Hamilton also had an Ecogate system installed in August 2008.

“We’re pushing the product as much as we can to suitable businesses,” Berry says. “The installation process at PWP was challenging but went off without problems, and we like the figures. We certainly endorse Ecogate and the energy saving potential it provides.”

How it works

Ecogate offers four models. PWP uses the ‘greenBOX12’ model on both fans. The model consists of a sensor and motorised duct gate for each wood processing machine on the dust extraction system, both connected to a central control system that operates with Ecogate proprietary software. The greenBOX12 can service up to 12 machines.

For the system to work, the extraction fan has to be fitted with a variable speed drive (VSD). Ecogate usually provides a VSD as part of the integrated package. However, the team that bought it decided to source a VSD locally, an Altivar 61 supplied by Schneider in Napier, to ensure security of maintenance and servicing supply.

The sensor is a small current transformer that clips onto the machine control system – usually a feed conveyor. When the operator turns on the machine, the sensor picks up the magnetic field the electrical current creates. It sends a signal by cable to the control unit. The control unit in turn sends a signal to the corresponding gate, also by cable, to open.

A 24-volt DC gear motor operates each gate. When the rotating reaches the fully open or closed position, the Ecogate system senses the stall current and disconnects the motor. The sizes of the gates in PWP’s system vary from 100mm to 450mm in diameter, with the smaller gates made of aluminium and the larger gates made of hot dipped galvanised steel.

When the operator turns off the machine, the control unit closes the corresponding gate. The control unit adjusts the fan’s speed to service only the active gates every time it opens or closes a gate. The fan speed is directly proportional to the required air flow, which is dependent of the size of the duct, which in turn is dependent on the dust-making potential of the plant to which it is connected.

If no machines are working, no gates are open, and the fan remains switched off. Each machine on the Ecogate system also has a manual switch to allow clean up or maintenance tests.

Relevant information about the plant and ducting system is programmed into the Ecogate control unit with a laptop computer at installation or when extra machines and gates are added to the system. The PWP team is now considering a WiFi connection from the control unit to their network to allow monitoring and diagnostics.

Application possibilities

Clifford notes fan speed is a good control variable for energy savings, as a centrifugal fan’s speed has an exponential relationship to the power it consumes.

“The site is already lean – the fan is the biggest energy user here. The value of the Ecogate system is you only have to reduce the fan’s speed a small amount to get a massive energy saving, and we saw this plainly in our analysis,” he says.

To comply with the EECA’s grant requirements, power consumption before and after fitting the Ecogate system on the first extraction system was independently monitored.

EECA business manager Murray Bell says in the past it has been easy for businesses to give energy management a lower priority because most types of energy have been relatively cheap in New Zealand. “That’s now changing as prices go up and more and more customers demand products with a lower carbon footprint.

“Many New Zealand businesses are now starting to see energy as a variable input cost they can control, rather than an overhead they are stuck with. Efficient energy use is a key part of improving productivity and reducing waste – the characteristics of a successful business.

“Our experience indicates a business can easily save up to ten percent of its energy costs by implementing simple, no cost or low cost measures. They can save as much as 30 percent by introducing an energy management program.

“There are many industries in New Zealand that could use this kind of control technology to reduce their energy use. EECA works actively with industry to support the adoption of new technologies and encourage the widest possible uptake,” Bell says.

The Ecogate system was also straightforward to install, according to Paul Reynolds from Electrotech Controls in Napier, who did the electrical work – and a spokesperson for DSK Engineering, Hastings, who did the sheet metal engineering work.

More than 1500 Ecogate systems are in use across the globe. Says Clifford:  “The concept is clever. It’s a classic example of how new technology enables a smart solution with existing equipment.

“More equipment does mean more maintenance for us, but we factored it into our calculations and we’re still showing a considerable saving. We had no issues with installing the system, and it shouldn’t impact on plant reliability. It’s also possible for us to install more machines in the existing extraction system if we need it – we don’t need it yet but it is an option for the future. Further savings in peak demand charges are also possible.”•

Jenny Baker is an Auckland-based freelance writer.

 Email : rosemary.scoular@eeca.govt.nz