How a new mechanical and electrical installation at the Royal Leamington Spa Hospital is helping to cut energy costs
Nik Chambers, operations directors at Greenways, discusses the mechanical and electrical installation for the new Central England Rehabilitation Unit (CERU) at Royal Leamington Spa Hospital for the treatment of neurological conditions caused by acquired brain injuries
A national centre of excellence, CERU’s new two-storey ‘Chadwick Unit’ has been constructed on the footprint of the former single-storey building.
South Warwickshire NHS Foundation Trust committed to spending around 30% more than the budget that would have been required simply to comply with NHS clinical standards for energy efficiency and the new unit’s energy consumption is 70% lower than that of the old building.
Greenways’ building services specification has played a major role in achieving this, alongside the thermal performance designed into the building by Hitchman Stone Architects, resulting in a BREEAM ‘Excellent’ rated facility that will become a benchmark for environmental specification in the healthcare sector.
Prior to construction of the new Chadwick Unit, Greenways designed and project managed an upgrade to the energy centre, with a bespoke HV and LV packaged substation and replacement of the existing 150kA standby generator with a 650kVA unit.
The team used computer modelling to inform design of a CHP appropriate for the building. This will run for 23 hours a day, providing 5.5kW electrical energy and 17kW of energy for the low-pressure hot water system. The pre-heated water will be stored in a calorifier at 50-600C and an electrical immersion will be used to pasteurise the stored water, heating it to 900C once a week to remove any risk of legionella.
Three air source heat pumps contribute a combined total of 25kW towards the optimised low-pressure hot water system, with each switching on as needed depending on the required heating load for the underfloor heating. The system incorporates individual thermostats for each patient area, with sensors to monitor the room’s temperature, humidity and carbon dioxide levels. The self-learning optimised compensating system is also linked to a weather station and external thermostat.
The Chadwick Unit includes an isolation suite with its own HEPA-filtered ventilation supply and extract system maintained at positive air pressure. The ventilation system throughout the rest of the building combines mechanical and natural ventilation in an innovative system designed collaboratively by Greenways and the project’s architects.
For the natural ventilation, actuators have been built into triple-glazed, aluminium-clad timber frame windows and cables run through these, connecting the actuators to the control system. The actuators are linked to the weather station and both internal and external thermostats, opening or closing the windows in response to changes in temperature, wind speed or wind direction.
Mechanical ventilation is linked to pressure and PIR sensors, providing a tailored level of ventilation for each patient, while conventional mechanical extract has been specified in the toilets, bathrooms and utility rooms.
LED lighting has been specified throughout the new unit, including intelligent LED emergency lighting, reducing both energy consumption and maintenance intervals. The system is operated via fully-programmable DALI lighting controls, with positioning of lighting units and sensors based on daylight modelling.
The electrical specification also includes a full audio visual installation at every patient bed, including access to NHS computers systems for members of the clinical team and full Wi-Fi access. Patient beds have been fitted with electronic games consoles and flat screen TVs to aid cognitive recovery and hand eye co-ordination as part of the specialist treatment programme.
The considerable energy efficiency achievements of this building stem from the trust’s commitment to investing in sustainability. High levels of insulation and triple glazing ensure an extremely low heat loss average of just 11w/m2 (compared to the average of 100w/m2) and, by aligning this with highly-efficient building services, the trust has developed an exemplar healthcare building.