The Art of energy efficiency: ammonia trumps synthethic HFCs &nbsp;&nbsp;

Alfa Laval has long promoted to the global market the benefits of its equipment to increase energy efficiency in industrial applications. Only now, the company is truly walking the walk. Alfa Laval’s Gunnesbo site in Lund, Sweden – the world’s largest heat exchanger plant – is now home to an ammonia installation that reuses waste heat and reduces heating costs by up to 80%.

World's largest heat exchanger plant undergoes upgrade

Alfa Laval’s Gunnesbo site was established in 1978 and now houses more than 1000 employees, producing 20,000 gasket plate heat exchangers annually. This huge demand eventually called for an upgrade to the heating system at the company’s largest site – an innovative solution that took some seven years of planning to come to fruition.

“It’s important that we can use the installation as a showroom to inspire our customers and colleagues around the world to follow our example. Of course there is the initial investment but in the long run this solution will make waste energy useful, we will save money and reduce our carbon emissions,” said site manager Arne Hermansson.

Alfa Laval sourced quotes from a company to use HFCs in the system but business and application manager Jesper Olsen said the 80% reduction in energy consumption thanks to ammonia’s excellent efficiency, as well as no threat of future penalties, made the choice between the two a simple one.

“We are now in that sense in front because we know we will not incur any penalties due to the type of refrigerant. So that’s number one. We received some quotes of another type of non-natural refrigerant but it was decided that we will do this in a natural way.” Olsen said.

Alfa Laval used only its own tried-and-tested heat exchanger components for the project, and with the help of an external contractor, devised a solution that is virtually self-sufficient for 10.5 months of the year.

Previously, the site used only energy from the external district heating plant , consuming around 3700MWh per year. But now, the heat recovered from the oil cooling system, which was previously cooled by air, is used for heating the facility, tap water, kitchens and offices.

Low-charge inspired: So how does it work?

The 35,000 m² workshop area has a large number of press lines as well as huge hydraulic oil systems, which create the power to press the heat exchanger plates. The hydraulic oil cooling system is then cooled by a closed system with water and glycol, as well as an external dry cooler.

The temperature of the oil cooling system was lifted from 30°C to 65°C in the heat pump to supply heating to the tap water. During the coldest months of the year the system utilises energy from the press lines producing roughly four million plates per year for the global market.

In the vein of modern packaged systems, Olsen was quick to point out that Alfa Laval’s project is in the realms of ‘extremely low charge’. The closed system produces 800 kW with around 40kg of ammonia, coming in well below the first ‘sensitive’ limit of 75kg. In Europe, a perfect low-charge system is typically deemed to use of 50 grams of ammonia to produce one kW, meaning Alfa Laval’s set-up is well below the safety limit.

The factory is divided into various manufacturing sections but with the press lines very centralised – the installation and set-up to the old system was simple. “It was very easy to install because the press lines are so centralised and in terms of future projects is was pleasing to see that the payback period is not bad at all.” Olsen said.

Both Olsen and Hermansson said they have been delighted with the results so far, “It was good to see that we could reuse the waste energy with a fantastic result as well,” Olsen said.

"As a system solution it’s not unique but as a supplier, I think it’s important to show that we can invest in such a good type of energy-saving system. Also to show that we can really save a lot in dependency on the external heating, before we had only district heating and we had the waste energy evaporating into the surroundings.” Olsen said.

“In doing so we will reduce our annual carbon dioxide emissions by 140 tons, which equals 40 returns flights from Copenhagen to Cairo,” Hermansson said.

Indeed, the Gunnesbo site now fits perfectly into Alfa Laval’s green corporate strategy, living up to the company’s ISO 14,000 environmental certification. Now, after seeing what’s possible, Alfa Laval’s other sites have shown interest, as well as customers.

“We have shown that it is possible at the Gunnesbo site and that can help others to make the decision – both our other sites are interested and so are our customers.” Hermansson said.