Refurbishment & Regeneration

Lancashire Constabulary has replaced the old oil-fired boiler house at its Hutton Hall site with four new Armstrong offsite manufactured packaged plant rooms. As a result, energy bills for the site have been reduced by £245,633 per annum and CO2 emissions have been cut by 744 tonnes a year.

The Constabulary has responsibility for 220 buildings, including police stations and operational centres, with an annual energy bill approaching £500,000 per year.

The system for supply of heating and hot water at one of its largest sites, the Hutton Hall Police Training Centre, in Preston, Lancashire, was in urgent need of replacement. The centralised oil-fired boiler, with two calorifiers for hot water supply, had stopped managing the site’s demand effectively some years previously, necessitating the installation of new heating systems for the accommodation blocks. In 2006, it became necessary to install replacement systems for the remaining buildings at the site, including a sports hall, administrative centre, firing range, dining room and teaching block. The existing system was inefficient, with extensive distribution losses, and engineers advised the Constabulary that the boiler could not meet the needs of the site over the coming winter.

As the site is financed from public funds it was important to reduce the energy costs as much as possible and a key part of this strategy involved a move away from oil towards a gas-fired system with reduced carbon impact.

The nature of the operations at Hutton Hall also had an impact, as the site houses several buildings with 24/7 demand, such as call centres on 24-hour duty, and the National Police Computer Database HQ. The timescale of the project was such that, once the capital investment was approved, there was insufficient time to carry out the installation using traditional onsite methods before the onset of the colder weather.

The Constabulary’s energy manager, Ed Palmer, carried out a feasibility study and found that the most effective approach would be the installation of four offsite constructed packaged plant rooms, incorporating highly-efficient variable speed systems based around the Armstrong MBS integrated heating solution, controlling Armstrong IVS pumps and pressurisation equipment.

The MBS incorporates fully modulating boilers, variable primary pumps, automatic fill/pressurisation unit and integrated controls, all pre-specified and pre-assembled for rapid installation on site. Instead of treating the condensing boiler in isolation, the MBS matches pumps, controls and hydraulic system design.

Part L2 of the Building Regulations calls for minimum overall boiler efficiencies of 84% in new build and 80% in existing buildings. The MBS can achieve overall seasonal efficiencies of 94%, providing significant energy savings and carbon reductions throughout the lifetime of the plant.

A year after the installation of the plant rooms, Lancashire Constabulary has been able to analyse the resulting energy reductions. The energy requirement of the site was reduced from the equivalent of 4,503,600 kWh per year to 2,550,730 kWh per year: a saving of 1,952,870 kWh. This reduction, calculated at a cost of 6.5p per kWh (oil) equates to an annual saving of £126,936.55.

Moving away from an oil-fired boiler in favour of condensing boilers has allowed further reductions arising from the prices differences between gas and oil. Calculated based on a gas price of 1.8p per kWh and an oil price of 6.5p per kWh, the cost saving as a result of the change of fuel is £118,696.45. This makes the total cost-saving £245,633 per annum.

The environmental benefits have also been considerable. Calculated at a rate of 0.27 kg of CO2 per kW, the move to the new system, together with the change from gas to oil, has led to a reduction in CO2 emissions of 744 tonnes per year.

Constructing the packaged plant rooms off site also meant that they were assembled concurrently with the excavations for the gas pipes, making it possible to complete the project by the target date of the start of October and to guarantee continuity of supply of hot water and heating for site occupants. The installation time was also reduced from several weeks to just a few days.

Ed Palmer said: “It was only when we analysed the energy consumption at the end of the first year, that we realised just how much money the packaged plant rooms had saved the taxpayer. The equipment has paid for itself in just a year, and will continue to deliver cost savings throughout its life.

“In addition, with the timescale we were working to, there simply wasn’t any other way that we could have completed the installation before the onset of cold weather. And being without heating and hot water was not an option.”

More information from Armstrong can be found at www.armstrongpumps.com or by calling 0161 223 2223.