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The future scientists and engineers joining the University of Edinburgh this October will have a head start on those at other establishments. For providing them with heat and electricity is a scheme that will also give them first-hand knowledge of the latest combined heat and power (chp) technology.

The university has over 200 buildings spread across the city. Over the summer break one of its two main campuses, King's ÐÇ¿Õ´«Ã½s, has updated its energy plant: its ageing steam heating system being replaced by a more efficient and cost-effective chp scheme.

The King's ÐÇ¿Õ´«Ã½s campus comprises around 30 buildings of various sizes and ages. Its teaching and research facilities cater for about 20 000 students.

CHP was chosen as the replacement energy source to help satisfy the university's environmental and sustainability policies. "Energy efficiency was the main driver," explains Lawrence Valentine, operations manager for m&e contractor Crown House. "The driving force was to incorporate the chp unit and support the university's stand on protecting the environment."

The firm won a £3.7 million contract for installation of chp schemes at King's ÐÇ¿Õ´«Ã½s and the nearby Pollock Halls student accommodation in mid-2002. Initially the contract for King's ÐÇ¿Õ´«Ã½s was to upgrade 25% of the heating system, with the remainder to be completed in stages as funding became available. The scope of this grew to encompass entire replacement of the steam system when the university was awarded a £1.63 million Community Energy grant towards the capital costs.

"The grant meant that they could do it all at once," confirms Valentine. The project was delayed until the grant results were confirmed early in 2003, enabling the design to be extended. "We developed the scheme with the university, in anticipation of the grant being successful, to encompass the whole of the campus," explains Valentine. "It was better economics for them. To keep part old and part new [systems] would have meant a lot of money being tied up in temporary arrangements during the course of the complete changeover. A lot of money would have been wasted."

By opting to take an open book approach at the tender stage, Crown House ensured that the university knew where every pound was being spent – including that which would have been needed to complete the scheme in phases.

"A lot of money was tied up in the temporary equipment and I wanted to flag this up," explains Valentine. The university asked Crown House to expand their design plan with this open book approach once the grant was won to encompass the whole scheme. By replacing the entire system at once, the need for temporary works was negated.

The installation
The installation of the new system at King's ÐÇ¿Õ´«Ã½s began in earnest on 2 June 2003, with a final handover date of 6 October – the start of the new academic term. "Heating was actually in place on 26 August in what was no mean undertaking," stresses Valentine.

The scheme involved the complete strip out and replacement of the existing steam distribution pipework with four kilometres of insulated mains pipe and a wet heating system. Four steam boilers in a central plantroom were removed and a 2·7 MWe gas-fired chp engine and two 7·4 MW high efficiency lthw boilers put in their place. Also included was the stripping out of heat exchangers and associated equipment from 19 smaller plantrooms located in the main campus buildings. These now house new pumpsets and control equipment. Prior to these works being started, three steam plants were installed around the campus to cater for the 24/7 heat and process steam needs of the research laboratories.

The main plantroom is sited at the centre of the campus and distribution runs from here to the 19 smaller plantrooms (or heat centres), from where the demands of each associated area are measured and controlled. Much of the external distribution is underground. Reusing old routes was deemed the best solution, however it also created complications as they could not be exposed until the academic year had finished. This meant that health and safety could be ensured and campus access maintained for deliveries. "Help from the university [maintenance] team was invaluable here," says Valentine. The staff were able to provide information on the routes beforehand, facilitating forward planning.

The chp plant is sized to the baseload electricity of the campus. Its use will reduce the incoming power required from the national grid, lowering costs and giving the university a payback period on the plant. The two 7·4 MW dual-fuel boilers will provide top-up heating for the winter months and redundancy for maintenance periods.

The heating system will run 24/7 to satisfy the research facilities. This will also benefit the rest of the campus. During the night the buildings will be injected with heat, reducing the cold start load in the mornings. Heat is efficiently available during night-time and this should make it unnecessary to put the boilers on in the mornings.

Doing the job
The contractor split the King's ÐÇ¿Õ´«Ã½ scheme into three sections for the installation: the main boilerhouse, the external distribution mains and the 19 heat centres. These were run as individual projects under an overall project manager, with separate teams assigned to each section. "The three section structure was needed for planning and practicalities," explains Valentine.

The 19 heat centres were all different – some were older than others and they were all of different shapes and sizes. "There was not one where we could look at prefabrication," says Valentine. It also meant that final drawings were not completed until close to the installation: "We took the attitude that we had to wait until we'd stripped out the old equipment before we made the final layout. We had a principle in place with what we wanted to do but we didn't cross every t and dot every i," explains Valentine. "By doing it this way it is more organised and has freed up a lot of space," he adds.

Crown House worked closely with the university on the design, much of which was carried out during the period between the tender and the confirmation of grant funding. The final arrangements were completed close to the start of work on site. "Had the drawings been done traditionally it would not have been achievable," stresses Valentine. The project time did not allow for drawing submittal and approval in the usual manner, hence the team's close working with the university paid off, with regular round table meetings the order of the day. The co-operation between contractor and client meant the tight deadline was met.

This design issue did not arise with the main boilerhouse. "We did know what we were working with here in terms of space so we could complete the design earlier, saving time later," states Valentine. This was important as a large period of project time was needed for the removal of the existing four steam boilers. Limited access to the plantroom meant these had to be cut into sections and demolished in situ rather than being removed complete.

The temporary steam plant is due to be removed imminently and the scheme commissioned ready for the arrival of the next influx of students. With an estimated annual saving of 2600 tonnes of carbon and £400 000 per year, the chp scheme is set to aid the education of future academics in several ways.