CHt was heavily involved in design development, spatial coordination of services and plant, as well as major plant installation logistics. CHt also undertook the installation of external services (water, HP gas, steam & condensate, HV /LV electrical systems) and the installation of multi services modules incorporating gantries/walkways/handrails at an early stage of the build process.
The site location posed early challenges, with CHt developing a plan to avoid the requirement of moving the main oxygen storage tanks/pipework serving the entire hospital campus. These were located to the west of the site – and were of major concern to the client. Crown House Technologies had to maintain access to the transport centre serving all of NHS Grampian, while carrying out road crossings and major plant installation operations at the south of the site.
The 'blue light' route for emergency vehicles ran to the east of the site and a HV cable had to be retained along the perimeter fence line to the north. Another HV line & water main ran through the centre of the site and had to be rerouted by CHt. The erection of a 35m high flue was carried out early in the build process as was the installation of a permanent power supply to the aircraft warning lights of the hospital's helipad, approx 1000m from the site.
Crown House Technologies was a key member of the team. Every aspect of the project, from the NEC 3 form of contract, was centered on teamwork.
CHt engaged with the client at the pre-construction stage to fully understand the requirements. A very early commitment to our supply chain was made to afford the time to develop the design and construction phase planning.
Along with our design team, we arranged for the NHS Grampian Estates engineers to be in attendance for several workshops to gain a better understanding of the new equipment that they were about to own and operate.
We actively encouraged the client to have an input before we committed to a construction design and final target price.
Visits to the major equipment suppliers were arranged and updates provided on procurement and construction activities during weekly discussions.
Clear and direct communications between all parties were considered crucial to the success of the project, and the workshops with the client and the specialist plant suppliers provided absolute clarity of the client requirements, an awareness of what the plant suppliers could deliver, and a commitment between all parties to deliver exactly what was agreed.
When issues arose, CHt met them head on with complete involvement of our client to ensure an agreed solution was achieved. The use of early warnings for any concerns from the client/design team or contractors helped diffuse any major issues. Weekly programme monitoring took place throughout the project which was fully transparent to the entire project team.
The engineering behind our delivery
This project took advantage of a wide range of innovative sustainable technologies in order to provide a cost‐effective and environmentally sustainable solution. Savings included a 16% reduction in CO2 emissions and a 39% reduction in energy costs. The plant was contained within one building, and was built on a brown field site.
The project includes a gas turbine CHP unit that can support approx 90% of the campus electrical demand (5.3MW). The combustion process also produces waste heat which contributes to a large proportion of the campus heating requirement (8.5MW thermal energy). The CHP unit exceeds the project specification and has the capacity to generate extra energy in case of future developments on site. In this way the energy centre is ‘future proof,’ and will have a long operational life.
A 1.5MW biomass boiler uses renewable fuel in the form of locally sourced woodchips. Steam from the boiler is distributed across the campus, providing heating, hot water, catering and decontamination. The carbon footprint is further reduced by the unique fully automated trailer system for storing the fuel and feeding the boiler. This ensures that no additional plant is required for this function.
In addition, two 8.5MW and one 6.5MW dual fuel boilers act to provide back‐up thermal energy. These boilers can operate on either gas or light oil, increasing fuel resilience.
The energy centre recovers 70% of the condensate from the steam produced, which is reused for feed water serving the boilers. This process is called condensate recovery, and makes the system highly efficient.
CHt delivered safely, within budget, and on time:
- One 5.3MWe Rolls Royce Jet Engine CHP
- One 6.5MW dual fuel boiler(Gas/Oil)
- Two 8.5MW dual fuel boiler(Gas/Oil)
- One 8.5MW waste heat boiler
- One1.5MW biomass boiler
- One gas compressor capable of compressing natural gas from 250mbarg to 19barg
- Two 90,000ltr double skinned oil tanks
- One 1250kVa standby generator
- Steam pipework at 180 ̊C /8bar up to 400mm Ø
- Condensate pipework up to 150mm Ø
- High Pressure Gas operating at 19bar
- Low Pressure Gas operating at 200mbar
- Welded blow down pipe and blow down vessel at 8bar
- Reverse osmosis plant & pipework
- Eighteen chemical treatment pumps and distribution pipework
- 40,000ltr single piece, stainless steel hot well tank
- One 26,000ltr cold water storage tank
- Three 800ltr condensate recovery pumping units
- BMS control panel and wiring
- HV & LV switchgear and wiring