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ENERGY MANAGEMENT


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1 July 2010 Cambridge Ext 8MB10


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15 August 2010 Running mean Figure 4: Recorded temperatures in multi-bed space, Addenbrooke’s Hospital.


recorded temperatures in one ward in a 1960s building at Addenbrooke’s Hospital in Cambridge in July and August 2010 were between 21.4˚C and 28˚C; the external temperature was between 9˚C and 30˚C (Fig. 4). Internal temperatures in this ward over this period were above 25˚C for 45% of the hours. This is above the level at which healthy people will start to feel uncomfortable. There were 36 night-time hours (between 21.00 and 06.00) above 26˚C. In many instances, the internal


temperatures were not helped by changes that had been made to buildings since their original construction. For example, patient safety concerns mean that window opening areas have been reduced, compromising the potential for natural ventilation. In other cases, problems are caused by poor control strategies, with there being one ‘set point’ (at which the heating is turned on) for whole buildings, regardless of the varied internal uses or patient needs within them. One maternity hospital was observed to be warm


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Bedford SRI


in summer because the heating was programmed to turn on whenever the temperature fell below 20˚C, which is the case almost every night, even in summer. The building, thus, started the day already warm, and extra heat generated by occupants, equipment and solar gain added to the problem. The research team also investigated the


ways in which the case-study buildings are being used and changed. For example, at the ‘Nucleus’ type case study, some of the internal courtyards, essential for natural ventilation and daylight, have been filled in to provide extra accommodation while maintaining clinical adjacency but at the cost of creating a deep plan building increasingly dependent on mechanical services.


Refurbishment strategies The team’s refurbishment strategies have been devised in detail. They have been tested not only in the current climate but also using projections of the UK climate to 2080. For the 1960s ward tower at Addenbrooke’s Hospital, five options are proposed (Table 1). The building is a ten-storey slab with a concrete frame and lightweight cladding; many of the wards have a view to the south. Refurbishment option 1 is a conventional scheme which insulates and seals the building and installs an efficient ventilation system (Fig. 5). It achieves 50 GJ/100m3


, but


for heating and lighting only; with the addition of small power uses it is likely to fall outwith the DH 55-65 GJ/100m3


range. More


radical hybrid/passive solutions are, therefore, needed. Of these, Option 5 from Table 1 wraps the building in a deep wall that serves to shade the windows and


Figure 6: Addenbrooke’s Option 5, SVPH, i.e. natural stack ventilation and perimeter heating. IFHE DIGEST 2014


Figure 5: Addenbrooke’s option 1, sealed, with mechanical ventilation delivering heating and cooling. Full heat recovery, with window blinds to control solar gain and triple glazing.


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Dry bulb temperature (˚C)


Solar radiation intensity (SRI) W/m2


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