Article 5 - Case study: Eliminating aircon in India!
Case study: Eliminating aircon in India!
Now that Spring is coming, amateur gardeners will spend more and more time in their greenhouses. Some of them are often better informed about natural ventilation than many building professionals. They certainly do not rely on expensive air-conditioning – quite the contrary, they know exactly how to use the natural resources of sun and ventilation to maximise the benefits for growing healthy plants. They do this by using the remarkably simple mechanism which opens and closing the greenhouse ventilators.
One is reminded of the greenhouse comparison when we look at a remarkable project recently completed in India. Here international integrated engineering consultancy Buro Happold and architects Chadwick International have just delivered a building which could have a significant impact on the country’s energy use. It is extraordinary because it has abandoned air-conditioning altogether in a country where temperatures can reach 40degC and certainly average the mid-30s for three months of the year. What is also significant about this building (but perhaps another story) is how cheap it was to build. There are many lessons to be learnt from studying this unique building.
The brief to architects Chadwick International was to build a low cost, low carbon workplace for Xchanging in the academic city of Shimoga, 280kms north west of Bangalore. Chadwick commissioned Buro Happold to determine whether a passive design approach could be taken to the building which at that stage had been ‘right sized’ used their proprietary Organisational SpaceTime Modelling® technique.
The first step was to analyse the climatic conditions at Shimoga. Subsequent optimisation studies could then be undertaken to determine building massing, facade design, air flow within the building floorplate and systems design, and estimate the potential energy savings passive design could deliver.
The client wanted to provide optimum working conditions to provide a comfortable and constructive workplace. Buro Happold’s team suggested that an entirely passive conditioning system which would maintain acceptable conditions in this extreme climate was possible. Using an approach based on adaptive comfort the design team was able to eliminate electrically driven cooling systems, saving 40% of capital cost. This approach is hugely beneficial both economically and environmentally and could help solve India’s energy crisis.
Buro Happold processed and analysed large numbers of potential design permutations using computational analysis and parametric modelling to achieve a single recommendation for the optimal design. This resulting solution could deliver a building design with an amazing 100% shading of direct solar gain but still provide high levels of daylight.
The design of the facade subsequently influenced the deep plan floor design which meant high floor to ceiling clearance and an internal atrium running through the building allowing daylight to penetrate deep into the centre of the building.
Wind analysis determined that a slight rotation of the building into the prevailing wind would maximise passive cross-flow through the north and south facades. Fresh air is harvested and channelled deep into the building through a series of four giant wind collecting stacks which form the top of the atrium roof light.
No design aspect was left unturned in order to deliver the most energy efficient building possible for Xchanging; high thermal mass, minimised internal loads, and cool landscaping minimising the heat island effect enabled the design team to create a building which reduces the operating costs by 25%.