Seaside attraction

It's complex for a quarter of a million pound spend," stresses Matthew Egan, Hills Electrical & Mechanical's Liverpool regional manager. "It's not a large value [project], it's a lot of detail."

Scheduled for a public opening on 20 June and to be fully operational by September, Southport's new park and ride facility offers more than its primary role suggests. Rather than a simple waiting area, Sefton Council has taken the opportunity to produce an educational resource and focal point for the north-west coastal town's tourism industry, creating the Eco visitor centre.

The aim was to create a practical demonstration of sustainable construction and renewable energy. This has meant the contractor getting to grips with ground loop heating and rock meters as well as distribution in a paper-insulated roof.

The Eco centre is sited around one mile south-west of the town centre. It is formed over one level and stretches to 80 m at it's longest point. Its European Redwood-clad exterior and gently curving shape nestle comfortably in the sand dunes creating a sanctuary that is in stark contrast to its nearest neighbour – the Pleasureland amusement park.

The centre's facilities include a waiting concourse, classroom, tourist information points, bus drivers' lounge and electric shopping vehicles loan area. Almost half a million people are expected to pass through annually. Classroom sessions are intended to cover the themes of transport, energy and tourism in related aspects of the national school curriculum.

It was designed by architect Cass Associates, with funding provided by Sefton Council, the National Lottery New Opportunities Fund and the DTI energy grants funder Clear Skies.

Providing renewable services
In March 2003 Hills Electrical & Mechanical won the contract for the m&e installation and commissioning by competitive tender in conjunction with Kier North West – one of its key clients.

At this stage the building was architecturally designed and the concept design for the m&e services had been completed by Fulcrum Consulting. Like many schemes of this type the planning and decision making took time and for a period the plans were shelved. The scheme was revitalised at the beginning of 2003, as Egan explains: "The original plans and scheme were retendered in a competitive situation. Then we redesigned and engineered [the services]."

Being an eco centre the intention was to be as energy self-sufficient as possible. To achieve this, systems such as ground loop heating, solar power and a wind turbine are being installed in addition to natural ventilation and rainwater collection systems for greywater use.

New mains supplies for water and lv electricity were supplied as the site previously contained a car park and these were unavailable. The plantroom here is a treasure trove of services all neatly packed into a small area virtually at the centre of the building.

"The plantroom will not be public access," stresses Egan, "but in the concourse area there will be electronic displays telling you what the wind turbine is doing and the solar panels – so people can see what is free energy and what is public energy."

The 20-m high wind turbine is due to be installed at the rear of the centre to provide electricity for use in the building. It can produce a maximum of 20 kW, three-phase power. Hills' project site manager Bernie Jones elaborates: "The wind turbine gives an average of 6-8 kW. It obviously carries 20 kW but it may be down at 2-3 [in low winds]." A motor at the base of its shaft can be used to start it moving or provide a boost if needed.

As well as providing 'free' electricity for lighting, heating and power, the wind turbine gives the potential for the centre to earn money. This required specialist switchgear in addition to the standard installation. "There's a special control panel that can feed back into the grid," explains Egan. "They're going to have a wind turbine that gives you free electricity to cover use in the day; in the evening the wind still blows so the turbine produces spare electricity. By feeding back into the grid the eco centre gets paid for producing electricity."

Jones adds: "You've got the evenings potentially to get money back. Its quite complex. You have to put a special meter in the system – a rock meter – and when the electricity board reads your meter they also read the rock meter and one offsets the other."

Ground heating
The ground loop heating system is the mechanical equivalent of the wind turbine in that its purpose is to provide a source of free, renewable energy. The concept is similar to that of a heat exchanger, where a cold fluid is passed next to a heat source – in this case the ground – and energy from that source warms the cold fluid, which can then be used to transfer heat to where it's needed.

The system comprises eight holes around 100 mm in diameter bored to a depth of 20 m each. These are at the rear of the eco centre and feed into a heat exchanger in the plantroom. The primary function of the system is to feed underfloor heating throughout the centre.

An estimated 12 kW of heat is available from this system. The ground temperature remains virtually constant at around 54°F so providing a continual source. The original plan involved only two boreholes, each 100 m deep, but once drilling began it was found that the ground was too fluid to bore to this depth. A limited depth survey had been successful and a land survey had shown the land was suitable for drilling, but the team were not to be defeated, another plan was sought.

"On seven of these boreholes they actually stuck to conventional piling," explains Jones. Specialists came in for the 100 m bore and when that didn't work, someone had the idea of just using the conventional piling as it seemed to be going well for [the turbine bore]."

A trench was exposed along the rear of the centre, then the pilers knocked in the casings and the pipework was installed, joined in parallel and connected to a manifold in the plantroom. This piling method proved cheaper and simpler than using the specialist rig. The underfloor system is split into five zones and controlled by the manifold.

Underfloor heating could not be used in the concourse because of its large size; electric space heaters are used instead. "If you wanted it in the concourse you'd need another 20 kW and you'd need maybe another dozen holes," explains Jones. The potential to expand the system exists but there would be a point at which it would become uneconomical. Jones expands: "You can dig as many holes to whatever depth is feasible and get as much heat rejection as you want, and then you need bigger heat exchangers and have bigger panels to accommodate it."

The system can also be used for cooling, by simply pumping hot water back through the pipes in the ground, thus rejecting the heat.

The distribution
The structure of the eco centre continues the theme of sustainability. The main structure is formed of recycled wood joists. The internal ceilings are recycled wood and the roof is wood clad in aluminium.

"What is unusual," stresses Egan, "is the insulation of the roof is paper – six tonnes of paper." When the roof void was formed, a series of holes were left in the ceiling, through which the recycled paper was blown, filling the space. The holes were then sealed with wooden joists. Paper was chosen for its good insulation properties, however, as Jones states: "Nothing could be fixed within the void because once they blow the paper in there's no access."

The solution was to have rewireable distribution trunking fixed within the void before the paper was applied. "It's a complete system where you use draw wires to pull [cabling] through, you won't access your actual containment," explains Jones. Any changes needed can be simply pulled through after removing the Klik light fittings. The Klik system was used for ease of maintenance, with luminaires hanging off a suspension system and being simply unplugged when required.

The remaining distribution is either suspended or in the floor – the trunkings were cast into the ground prior to the pouring of concrete. The early involvement of Hills on site enabled the success of this installation. Egan explains: "We had to put underfloor heating in; tie this to the rebar in the concrete and come up with a pre-compartment containment system to support that within the concrete floor."

The installation
For the specialist areas of installation such as the ground loop system and wind turbine, Hills employed subcontractors. Some of these firms were new to the contractor but there are few specialist firms in the UK and it was vital that their skills were employed.

Some of the firms selling the high-tech renewables equipment will only do so under guarantee that registered firms and preferred suppliers complete the installation. Thus they can ensure the quality of their product in situ. Egan explains: "There was a choice of one or two wind turbine specialists, one or two ground loop specialists and the same for the solar collectors, the criteria being that it's them that have the licences and are certified Clear Skies companies."

Jones elaborates: "On most jobs you get preferred and nominated suppliers, here its paramount you use them because the Clear Skies grant which is going to pay quite a lot of the building, is on the basis you use those people. If you don't use those people you don't get the grant."

Despite their working restrictions, Jones and Egan report close working between the project teams and a "three-way channel" of information between it, the architect and main contractor.

If you're in Southport this summer, tear yourself away from the TraumaTizer rollercoaster long enough to visit the centre – you won't be disappointed.