The Eden Project: Back to the future

Like the DeLorean in Back to the Future, the Eden Project was created by a visionary and has captivated the imagination of millions.

When it opened in 2001 after a £141m build, it raised the bar for visitor attractions, revitalised Cornwall’s economy by £2bn and challenged conventions in building design.

It remains radical 20 years on – even the facilities team call it The Space Ship.

And just like the Doc’s Time Machine, the Eden Project has been given a new core to keep it ahead of the game. The most powerful governments will see it first-hand during this summer’s G7 summit. And like the CIPHE, the Eden Project team will be making a big noise at the UN climate summit COP 26 in November. But before that, P&H Engineering has been granted an exclusive insight into the massive overhaul that has brought the centre’s critical systems into the 21st century.

The demands are significant: support a million visitors a year, sustain two different environments for rare plants – and enable movement between the two – and run conference and office buildings. And the critical demand is the drainage and pumping system that prevents the former clay pit from flooding.

So how do they do it?

Energy manager, Charles Sainsbury says: “The way we approach sustainability is as a negative – we want to give back more than we take. That’s vital in an ecological emergency.”

The complex consists of two biomes – one tropical and one warm temperature – which share a walkway. Then there’s a roofless biome that makes use of the local climate – which is similar to Chile – and two visitor complexes. The 35-acre site is home to 2 million plants that need watering.

First principles

Kevin Bate, site manager has spent 13 years overseeing the heating, ventilation and critical pumping equipment. He works with two mechanical engineers.

He says: “It’s amazing, world-beating engineering. But we have huge electricity need. That comes from an 11,000-volt internal ring and six sub-stations. “There’s also the plumbing and an industrial pumping system. If they stop working, Eden will fill with water again very quickly.”

Three Hidrostal medium pressure pumps supply rainwater to the tropical waterfall linked to ponds and watercourses. All three pumps, totalling 60 kW, operate in a duty/assist mode in daytime dropping to a single pump at night. “They are testament to good pump design,” says Bate.

But the centre also had its limits. “When Eden was built, a lot of people put in a lot of infrastructure,” says Bate. “Everything was bespoke and built on a limited knowledge and resources. Some of it is unique; it pushes you to the point where you need to step back to think about how it all works. That’s been very challenging.”

There was one problem: “What we ended up with were a lot of things that were not really working together.”

An audit revealed the extent of problems. Bate says: “We needed new building controls, lighting and more use of renewables to get closer to our vision. We needed to look at building performance, energy use and how to maximise the lifetime of our kit.”

The solution was to “give the spaceship a new steering wheel” to run a single system. He says: “The heating distribution was being run through a heating distribution ring main. There was nothing gelling it together.”

That was critical: the site has 33 air handling units that extract heat. In total there were 49 separate control systems, most no longer supported by the manufacturer. And a contractor was coming in to reset parts of the system with a laptop. “It made me think,” says Bate.

The resulting brief was to create one system – with remote access – that would save energy and money. There would be three phases: upgrade, unify and future development.

A contract went out and 17 firms bid – all big names. The winner was Priva, a Dutch company that works with agri-businesses. It designed the system and CambridgeHOK – “a lovely company to work with” – installed it. Bate says: “They asked to see inside our systems, including office blocks. No-one else did. We had a three-part system, pumping water all the time. They converted it to a two-part system that can be shut down and modulated.”

All 10 main system controls were obsolete so were replaced. The firm also installed inverters on its 33 air handling units and moved their machinery outside. Bate explains: “You’ve got humid temperatures and insects; perfect for corrosion.”

The team replaced more than 700 lights with LEDs, installed direct hot water providers and new condensing boilers. All this is managed by an energy monitoring and targeting system to achieve consistent use needing only minor adjustment. Charles Sainsbury, energy manager, says: “Turning off kit with smart timers, using solar in our office and workshop buildings, building performance, maximising the lifetime of our kit - eventually it adds up.”

The results were huge. Eden has saved £414,860 on electricity and £43,059 on gas in just three years. The investment paid for itself in two years – and saved 781.4 tonnes of CO2 over the three-year period. There’s been an added labour saving too. Bate says: “If you can lower the temperature, you slow the metabolic rate of plant growth so they are not climbing. You’re saving energy and the plants aren’t stressed.”

The unifying stage involved bringing the pumping network onto the single control system – making better use of grey water from roofs for toilets. Bate is particularly proud of an installation that the public never sees: “Inside the Banrock pumping station, there’s a piece of plant that’s a work of art.”

So what next?

For the future phase, a wind turbine is going to be added to the energy mix to phase out gas. Then comes geothermal supply. A £17m project is starting to drill a 4.5km hole into the ground to generate up to 7MW a year of electricity to heat and power the entire site and thousands of nearby homes.

Sainsbury says: “Good engineering is about simplicity. We want to work with nature and that’s what we’re doing.”

The COVID-19 outbreak shut the site down: Doc’s advice in the movie - ‘Don’t go to 2020’ - was right. But it hasn’t stopped work at the Space Ship. Plans were announced in February for a spin-off centre in Morecambe – and other sites around the world are also under way.

Plans are also beginning for an eco-hotel at the Cornwall site.

Sainsbury explains: “We’ll be growing our own crops, preparing food on site, putting energy into the local grid and meeting our zero carbon remit. That’s what we wanted to do at the start.”

The spec sheet

• The Eden project works by mimicking our own eco-system.

• The world-famous domes are made from a space frame with two layers. The steelwork weighs only slightly more than the air contained by the Biomes.

• The transparent ‘windows’ are made of ethylene tetrafluoroethylene copolymer (ETFE). Each window has three layers, inflated to create a two-metre-deep pillow. They weigh 1% of the equivalent area of glass but are strong enough to take the weight of a car. They transmit UV light and self-clean. Heat soak from the floor starts the heating process.

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