Buildings come in all shapes and sizes, and must respond to different environmental conditions, different site characteristics, different client aspirations, individual user needs, local and regional planning policies, etc, etc. It is for this reason that the key principles associated with Active Buildings are deliberately not prescriptive – the Active Building concept is based more on an approach, or process, for delivering low energy buildings, rather than focusing on particular technologies.
To reflect this, the Active Building Toolkit I am developing will be underpinned by an interactive process flow diagram that will provide a step by step guide to designing and delivering Active Buildings in relation to the RIBA work stages. I plan to develop this using the Integrated DEFinition Method (IDEFØ), which is designed to model the decisions, actions, and activities of an organization or system – in this case the RIBA work stages for the design and delivery of building projects. This, alongside the documents within the Toolkit, will describe the considerations that should be made at each of the stages.
The starting point for an Active Building is an efficient building fabric and optimised passive design to reduce operational energy. Regulated loads are further minimised using energy efficient systems. Where practicable building loads are met using building integrated or onsite renewables. In addition to reducing peak loads, and preventing oversizing of plant, the inclusion of electrical (including electric vehicles) and thermal storage allows interaction with micro-grids and the national energy network to be managed. Intelligent control is essential for an Active Building, both for the control of building systems and to manage interaction and trading with the grid. Ongoing and consistent data capture will enable analytics and insight to feedback into the Active Building design process, and optimisation and refinement of predictive control strategies.
One of the documents I have been working on this week is an Active Building Technology Showcase, which provides information on the sorts of technologies that could potentially be used to deliver low energy, low carbon solutions. Feedback from my focus groups suggested a need for information on available technologies, including the more innovative, emerging technologies that designers and contractors rarely have time to explore – having these set out in one handy document will help encourage innovation and use of low carbon technologies in building projects. The technologies included in this document are based on those I have knowledge and/or some experience of and certainly isn’t exhaustive.
When developing the energy strategy for a building, as well as taking into consideration site constraints and opportunities, talking to those responsible for ensuring the building operates effectively is critical. Residential, educational, commercial, industrial building types all have very different requirements and are operated very differently. For example, clear feedback from those operating school buildings is that, unless someone else is paying for it, schools often don’t want renewable energy generation on their buildings. Understandably, they don’t want the extra financial or maintenance burden of PV roofs. Community energy schemes, such as SCEES in Swansea, which install and manage PV installations on school buildings, can be a solution here.
The energy strategy must of course be developed in conjunction with other key design decisions. Large windows overlooking playing fields in school buildings, for instance, are not generally favoured by teachers as they can be a distraction for pupils. If relying on the natural light from those large windows as part of the lighting design within the energy strategy, this is an important factor. In this situation, to focus pupil’s attention on the class in hand, teachers will pull the blinds down and switch the lights on, negating the original design intention of the windows to flood the classroom with natural daylight. Unless large overhangs or pergolas are provided on south facades, blinds are drawn whenever the sun is shining to avoid overheating and glare in classrooms. North lights are more suitable for classrooms, as they provide good levels of natural daylight, without the overheating and glare issues. However, there needs to be a good balance between providing natural daylight and providing a thermally efficient building envelope to minimise energy for heating – Every design decision impacts the energy strategy! Glazing on east and west facades is the most difficult to control, so schools are often designed on an east-west access to enable north and south glazing only, which is easier to control. This also works well if including solar energy generation on the building.
I have recently been involved with the design of an off-grid classroom, which presents a different set of challenges. The site is located at high altitude and is often shrouded in low lying cloud cover, so use of solar energy alone cannot be relied on to supply all of the energy demand for the building, especially in winter, even with battery storage. The occupancy of the building will be intermittent, and the building will have minimal use in the winter months, due to the location. However, some space heating and hot water provision is required, and systems suited to the site, occupancy and operation must be carefully selected. Other fairly large power requirements include water treatment and pumps for distributing harvested rainwater. As there is no option to connect to the grid, energy demand will be minimised as far as possible through the building design and it may be necessary to accept that in the depths of winter, it could be a struggle to heat the building to temperature levels people are used to in buildings.
Retrofit of existing buildings poses different challenges again, requiring careful thought and consideration to the most appropriate energy efficiency measures to deploy. The UK Government recently announced £80m of funding for green technologies (such as renewables, heat pumps), heat networks and insulation measures to upgrade the existing building stock in England. However, not all existing buildings are suited to solutions such as external wall insulation (EWI) and the unintended consequences of applying the same measures to all buildings can result in (and has resulted in the past) detrimentally affecting the fabric of existing buildings. A flexible approach to retrofit is needed that will enable measures to be adopted appropriate to individual situations. This was discussed in a recent blog post by the Active Building Centre, where in some instances a technology approach may be more appropriate than improving fabric efficiency.
I am hoping the Active Building Toolkit will prove a useful set of information for those embarking on low energy buildings of all types, as well as describing a clear process for achieving low energy aims and objectives.
|Active Building Document||Description|
|Code of Conduct||A document to accompany contractual documents that sets out the drivers for any Active Building project and commitments for all stakeholders involved in a project|
|Glossary||Key terms and definitions associated with Active Buildings|
|Design Guide||Describes Active Building concept, the 6 key principles and key design considerations to help achieve each of the principles, data collection, LCA and WLC|
|Frequently Asked Questions||A collection of frequently asked questions categorised into headings linked to the challenges identified in the Pilot Project|
|Technology Showcase||A selection of technology options for possible inclusion in an Active Building project, including emerging technologies|
|Project Template||A structured way to record a project from RIBA Stage 0 to 7, including key decisions made, information exchanges, photographs, etc – this will become a Case Study post project completion|
|Case Studies||Step-by-step record of the design, delivery and operation of an Active Building, linked to RIBA stages, including lessons learnt (based on Active Building Project Template) – current case studies show the development of this idea, from the Active Classroom to the Active Office to the Project Template|
|RIBA Plan of Work Checklists||Key checks at each of the RIBA work stages to comment on – whether they were achieved or not, including explanations – to be completed before moving to next stage|
|Induction||A 15 – 30 minutes presentation that all people working on an Active Building project must watch before they commence their involvement.|