INFRASTRUCTURE AND RAAC MANAGEMENT
FOR 100 MWH USEFUL HEAT
Useful heat
Assumed efficiency / SCOP Energy consumed Operational CO₂e Carbon saving Reduction
EXISTING
GAS BOILER 100 MWh
90 per cent
111.1 MWh gas 20.3 tCO₂e
– –
handling units, each dedicated to serving the acute and weaning ward. The acute patient bedrooms are designed as neutral- pressure rooms, where air is supplied at a constant rate and regulated by Constant Air Volume (CAV) dampers to maintain the required airflow. In contrast, the weaning bedrooms have been
upgraded to provide greater operational flexibility. In addition to supporting weaning services, these rooms can also be utilised as acute care beds during periods of increased winter pressures. This is achieved by using Variable Air Volume (VAV) dampers, which regulate extract airflow rates within the rooms, while ventilation rates to adjacent corridor areas are adjusted accordingly.
Sustainable application and use of Air Source Heat Pumps The project incorporates a sustainable energy solution using Air Source Heat Pumps (ASHPs), which provide heating, cooling, and domestic hot water for the ward. The VIC has been equipped with three Airedale AlphaChill Plus ACHP P55.4 units. The primary objective was to eliminate reliance on gas-fired heating while also providing an efficient cooling solution. Each P55.4 unit delivers approximately 150 kW of nominal heating capacity and 139 kW of nominal cooling capacity from a reversible air-to-water heat pump. At Airedale’s published rating conditions, the unit achieves a heating Coefficient of Performance (COP) of 3.17, with Seasonal Coefficients of Performance (SCOP) of 4.15 at W35 and 2.96 at W55. The adoption of this ASHP technology provides several
key benefits: n Significant reduction in operational carbon emissions
through the replacement of natural gas heating with electrically driven heat pumps.
n Provision of both heating and cooling from a single plant system, reducing the need for separate boiler and chiller installations.
n High efficiency at lower water temperatures, making the system particularly suitable where ward emitters and air handling units operate at 35°C to 45°C rather than the traditional 70°C to 80°C associated with boiler systems.
n Hot water production up to 60°C, providing flexibility while maintaining good overall efficiency.
n Inverter-driven operation, allowing the units to modulate output in line with demand rather than continuously cycling compressors.
n Dual refrigerant circuits, improving system resilience compared to single-circuit alternatives.
n Use of R32 refrigerant, which has a Global Warming Potential (GWP) of 675 and zero ozone depletion potential. Airedale also states that the design requires approximately 16 per cent less refrigerant volume per kW than an equivalent R410A system.
n Low operational noise levels, with the P55.4 rated October 2026 Health Estate Journal 73
ALPHACHILL P55.4 @W55
100 MWh 2.96
33.8 MWh electricity 4.4 tCO₂e 15.8 tCO₂e
~78 per cent
ALPHACHILL P55.4 @W35
100 MWh 4.15
24.1 MWh electricity 3.2 tCO₂e 17.1 tCO₂e
~84 per cent
at approximately 54.6 dB(A) at 10 metres, making it well-suited for healthcare environments where plant is located close to wards, patient bedrooms, or neighbouring properties.
n Support for NHS decarbonisation objectives through the reduction of fossil fuel consumption and associated carbon emissions.
Using the government’s 2026 greenhouse gas conversion factors, published in June 2026, it is possible to estimate the carbon emission savings achieved through the Ward 6 upgrade. A breakdown of the estimated carbon reduction is provided in the table shown above. Replacing a conventional natural gas boiler operating at 90 per cent efficiency with an AlphaChill Plus ACHP P55.4 Air Source Heat Pump could reduce operational heating-related carbon emissions by approximately 78 per cent to 84 per cent, based on current UK grid carbon factors. The level of carbon reduction achieved depends primarily on the heating water temperature and the SCOP attained in operation. Nevertheless, the adoption of this technology represents a substantial reduction in CO₂ emissions and makes a significant contribution towards the NHS’ Net Zero carbon objectives.
Electrical improvements UPS including IPS system The Ward 6 Main Distribution is fed via A&B supplies alongside a standby generator with UPS’s offering support during any given change over from Supply A to Supply B, Mains Changeover to Back up Supply. The changeovers locally to selected distribution are supplied through Manual Transfer Switches giving the option of A or B preference. Two UPS systems (A and B) were introduced in line
Table 1. Estimated carbon reduction.
Single Acute Bedroom featuring single arm pendant with medical wall trunking.
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