In order to deliver the European energy and climate objectives to 2050, significant changes are essential in the building sector, especially regarding the existing stock. Indeed, there is a huge potential for action, also regarding historic buildings. In this regard, today the question is: how to combine the building protection requirements and the application of energy efficiency measures?
This paper tries to answer, evaluating if the refurbishment of historic architectures, in order to achieve very low energy need, is possible and economically feasible. More in detail, the applicability of the cost-optimal methodology (EPBD Recast 2010/31/EU) for historic buildings is discussed, by adopting the macroeconomic perspective, in order to take into account of the energy, environmental and economic impacts of about 60 packages of energy efficiency measures. The study is aimed to introduce a methodological approach to define reference buildings for historic architectures, through in-situ investigation of structural and energy peculiarities and, as real case study, the refurbishment of an Italian building of the XV century is presented. Moreover, guidelines are proposed to properly select energy efficiency measures, according to a point of view of cost-optimality. Conservation, aesthetical requirements, structural and energy issues are considered, as well as the incidence of all economic factors.
A University Renovation : A Case Study
An award-winning project at the University of Surrey has led to an impressive “newish” campus without the impact of demolition and rebuild.
Surrey, like many universities in Britain, had a number of buildings from the late 1960s and 1970s, which were looking dated, had major fenestration failures and were becoming increasingly expensive to run.
But it carried out an analysis before deciding on a new building programme and discovered that refurbishment was the better option all round.
Cost SavingsThe university’s Director of Estates and Facilities Management, Derry Caleb, said: “Our analysis showed that renovation would have a lower capital cost with much less impact than a new build but would still deliver similar energy efficiency and running costs.”
The university had undertaken other remodelling projects in the past and knew from this experience that a lot of the work could be done floor-by-floor while the buildings were still in use.
The decision was then taken to upgrade a number of buildings over a period of years – avoiding the environmental impact of a new build programme.
Good StructureThe 1960s buildings were all of similar construction - heavy concrete structures with concrete panels constructed off site, bison beam and screeded concrete floors and roof structure. They were a heavyweight design with large thermal inertia - deep plan design, vertical risers, single pipe heating systems and an overall well-thought through design.
- As part of the project, around 14,000 m2 of double glazed, insulated panels were fitted in place of older single glazing across nine buildings and this massively reduced heating requirements.
- Main ventilation plants were replaced, infrastructure plant was renewed and the district heating and cooling plants were expanded.
- The university’s annual energy use has now dropped by around 8,000,000 KwH, heat loss is 60 per cent lower and its buildings-related C02 emissions have been reduced by more 2,000 tonnes per year.
“We were able to coordinate our remodelling with other University changes and managed to compress major projects into three or four month periods each year with minimal disruption.”
Worthwhile ResultsHe says the project proved that in many cases, older buildings are worth investment and if upgraded, can perform as well as most new buildings of similar design.
“I think our experience is very transferable to other large developments. We showed that renewal can be carried out sustainably and there are significant environmental benefits in more effective space management.”
Derry said the key lesson from Surrey’s refurbishment is that structural design needs to be proportioned correctly to allow for flexibility.
Buildings should be able to deliver a level of “churn” because departments change, teaching methods vary and academic disciplines alter.
“Floor to ceiling heights must be capable of allowing remodelling to take place and you need to consider how replacement of ventilation and infrastructure can be undertaken, either by floor or by building.
“The building design must have suitable sized vertical routes through a building to a replace infrastructure and services.
“The additional 1-2% on capital cost to allow for these elements will have an insignificant impact on short term capital but will have a major impact on the long term sustainability of individual buildings,” he said.
“If these elements are allowed for at construction stage, you have a more sustainable design that has longevity and helps to future-proof the project.
Design is Vital“If a building is intended for a 60 year life, then it must be designed to allow for this type of major refit and the consequences of that work should be understood at design stage. “Since most institutional buildings ARE designed for this timescale, all we have done is carried out the refurbishment and remodelling that you should expect and plan for.
“We all recognise that these may not be architectural “gems” but they are sustainable and the feedback we’ve had from staff and students has been excellent.
“From their perspective, the internal environment is similar to that of a new building.”
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