Improving control at the Eden Project

Surely everyone knows of the Eden Project in Cornwall, but very few know about how the complex environments in the biomes are controlled. Those systems are receiving major upgrades — and winning industry acclaim. Ken Sharpe has been finding out more.

Awards schemes are a growing industry, and such schemes culminating in a major bash hosted by a celebrity are no stranger to the building-services sector. Inevitably, some entries can pop up in more than one scheme — and the very best entries can be acclaimed by more than one scheme, giving added credence to their quality.

The progressive upgrading of the control system for the Eden Project in Cornwall and associated energy-management programme to reduce the site’s energy consumption is one such project.

In the last couple of months it has received the Building Controls Industry Association’s award for technical innovation of the year (projects) and also helped Matt Hastings, energy manager of the Eden Project scoop the energy manager of the year award in the scheme operated by the Energy Systems Trade Association. The BCIA award was received by Matt Hastings, David Moore (maintenance manager with the Eden Project) and Ross Hibbs, managing director of CambridgeHOK, the company which was commissioned to engineer and install completely a new control system and which also entered the project for the BCIA awards.

Their efforts are appreciated at top level in the Eden Project. Its founder and chief executive, development, Tim Smit, who says of Matt Hasting’s award, ‘This is a wonderful accolade in which a young man of passion and conviction has driven Eden’s performance to a level which has seen him in Energy Manager of the Year among competition of the very highest pedigree. We are extremely proud of him and know that for Matt, this is only the first of many achievements in the coming years. How fantastic that Cornwall, the county that is making waves in a quest for a low-carbon future, should be the home of a man and a project epitomising this aspiration.’

A detailed perspective on the Eden Project was presented by David Moore at the National Conference & Exhibition of the BCIA.

The headline figures for the Eden Project were savings of 1.73 GWh in gas and electricity since June 2010. Gas consumption was 15.4% under baseline performance, with electricity 8.2% under baseline performance. Consumption was assessed relative to 2009/10 baseline performance.

The Eden Project is one of the UK’s major tourist attractions, with nearly 14 million visitors since it fully opened in March 2001. However, its energy performance and control capabilities of its systems suffered at the hands of ‘value engineering’ in the face of increasing costs during its construction — a familiar-enough story, posing problems to which David Moore and Matt Hastings have responded magnificently.

In his presentation to the BCIA conference, David Moore explained that the control system was obsolete when the site opened and totally out of date five years later. It was also no longer possible to maintain it.

The sort of problems faced in managing the site effectively was the existence of 49 control systems, none of which communicated with any other. There were also operational issues such as air-handling units in the biomes being controlled in groups of four and which could be delivering heat at the same time as roof vents were open.

Heat for the 33 air-handling units was drawn from a ring main of hot water circulated at 95°C.

The task of implementing an effective controls system was given to CambridgeHOK to engineer and install a new control system supplied by Priva. Interestingly, and highly relevant to this project, is Priva’s expertise in controls for horticulture and also the built environment.

The development of the new scheme saw two Priva engineers and its horticulture controls expert visit the Eden Project and also Eden’s energy, technical and horticultural team visiting Priva’s headquarters in Holland. This combination of expertise has resulted in the Eden Project being one of the first projects in the world to fully integrate horticultural and building-control systems. The overall result is a more comfortable environment for staff and visitors as well as substantial energy savings.

A vital aspect of how the Eden Project is managed is that energy management is kept separate from the building-management system. One role of the building-management system is to maintain the environment in the biomes so that the plants flourish. Measures to save energy might jeopardise this.

The work was planned in several stages.

The first stage included the primary replacement of obsolete building controls, including those in air handling units.

Other work included the installation of a number of small boilers in the biomes to meet small loads that occur outside of periods of peak demand. For example, the peak heating load of the biomes could be 3.5 to 4 MW at -5°C ambient, falling to just 75 kW by day. That simple measure reduced gas costs by £25 000 a year. The installation of outside air monitors provided information about ambient conditions that was used to permit the ring main to cool down when possible.

The total cost of the first phase, during 2010, was about £70 000, with predicted savings of about £30 000 a year. The project was engineered to deliver maximum energy-savings opportunities in the early stages to fund latter-stage investments.

The second phase, during 2011, involved replacing and integrating horticultural control and improving the control of the air-handling units. Every air-handling unit now has inverter drives. The total cost of this phase was about £270 000, with predicted savings of £100 000 a year.

The project continues to move forward with the planned replacement of the Scada system and the integration of pumps, lighting and other controls. An investment of about £70 000 is planned during 2012/13, with predicted savings of around £26 000 a year.

Other measures will push up the total proposed investment during 2010/13 to about £600 000, with total expected energy savings in the region of £156 000 every year thereafter. By 2013, a 25% reduction in CO2 emissions is predicted, compared to a 2007/8 baseline.

One notable improvement is the installation of daylight sensors to enable lighting to be turned off automatically when possible. Previously, lighting used to be turned off manually on sunny days.

Before this long-term project, none of the 49 controls systems communicated with any other. That situation has since improved significantly, so that about a third of the control systems now talk to one another, covering functions such as lighting, ventilation and other HVAC services. The longer-term aim is for 70% of the systems to be under the same control.

While the monitoring of the use of energy and other utilities services and the effective use of the building-management system both contribute to improved performance and reduced costs, the roles of energy management and the BMS are kept separate. A key consideration is that condition in the biomes must not be allowed to jeopardise the health of the many types of plant life. Whereas reducing temperature by 0.5 K can, and has, saved energy some plants will start dying in half an hour at a temperature of 17°C.There is still much work to be to, and the new systems open up a host of possibilities for the more effective control and operation of the Eden Project.

Let us give the final word to BCIA president Ian Ellis, who chaired this session of the conference: ‘There are two clear messages from this presentation. One is that “value engineering” does not work. The other is that the building-management system is the one thing that can bring together all the various elements involved in running a site effectively and efficiently.’

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