The concept of a dream home often embodies a lovely little hideaway with modern comforts and scenic views that offer ample privacy. But this also means that these fabulous homes consume the most power and water, making them resource inefficient. Our homes are significant emitters of greenhouse gases, firstly in the materials used and the construction process, and, more significantly, in the energy and other resources used over the life of the building for cooling, heating, cooking and washing. By designing your house with the knowledge of the local sunlight, wind and temperature patterns you can enhance comfort and lessen or eliminate the need for air-conditioning or heating.
Bioclimatic or climate responsive design blends the study of climate, ecology and biology with urban macro-scale and building micro-scale design to improve indoor living conditions and most importantly decrease energy consumption. This approach to design is in vogue and has been gaining popularity for a while now. There are many benefits to this design approach that go beyond typical eco-friendly materials. Energy-efficient home design can cut back on your power bills and create a more harmonious and healthy environment. Relevant case studies have been employed in this article to illustrate the main idea that one will need to consider before starting the design and construction.
Bioclimatic design begins with your architect performing a through site analysis. It’s imperative to determine the weather conditions, climate, soil types, wind speed and direction, cooling/heating days and sun path. Also, one must look at the hydrology of the site, namely water flows, habitat and geology of the site to gain awareness of the rain water percolation and the ramifications of building in that specific place. Climate responsive design utilises a holistic approach that relies on deciphering the most optimal location for the building layout, considering the prevailing winds, access to infrastructure, existing natural and geological features and the natural hydrology across the site with an outcome that respects the landscape. Building envelope design varies greatly by geographic area. When designing the building, factors such as insulation, vapour barriers, and air barriers will vary radically depending on whether the project is in cooler northern climates or in the hot and humid southern regions.
This Bioclimatic House from José Luis Rodríguez is a design that is sensitive to the topography and uses local sourced materials to create an energy efficient living space. The building materials selected have a high thermal mass (ability to store energy) that include basalt and stone in the north facing walls. In addition, the architect has employed volcanic charcoal as roof insulation (which is known for its thermal resistivity and tensile strength).
It’s all about the sun, so it is important to orient the building based on cardinal directions. The goal in the tropics is to decrease the amount of sun that heats the building in the summer (hence using less energy to mechanically cool). During winters, like in the case of Rodriguez’s bioclimatic house, the architect envisioned the living space as an interaction area used to warm the house. It behaves as a conservatory with it’s fully glazed walls oriented southward with respect to the sun so that the house captures as much free solar energy as possible during the day and conserve the same for the night within it’s thermally massive walls. The net effect of this results in the house using less energy to mechanically heat the living space. The slope of the structure of the day area is determined by optimizing the solar radiation on the solar panels integrated into the roof, generating electricity and hot water.
For the summer, window areas and glazing types selected are based on orientation. South and West facing facades should utilize a window area appropriate to its orientation and glazing should utilize a double paned glass with a low-e coating to minimize the amount of heat transmitted into the space in the hottest months while keeping heat inside during the cooler winter months. Having a verandah with deep overhanging eaves particularly on the southern and western side is a useful technique to shade any exposed walls. Large openings and/or banks of louvres allow the cooler air from under the verandah to be utilised in keeping your home cool.
Designing for natural ventilation is key for reducing human dependence on air conditioning. Cooling through natural ventilation (single sided or cross ventilation) demands a good exposure of the building and its windows to the dominant breezes. One way to ensure natural ventilation is to minimize the building footprint. Question the true needs of the design — do you really need that much space? Are there ways that spaces can become multi-functional? Is it possible to add extra stories to make the footprint smaller? That way, the building will have less excavation cost, and the elevated house has the ability to catch a breeze more easily than the ground level homes and an increase in natural daylighting.
Most buildings in this day and age are designed to keep occupants fairly comfortable, at around 21 degrees Celsius. However, it’s becoming more commonplace to recalibrate the occupants comfort standards with climate responsive design. This goal is achievable by using natural systems, primarily the sun and the wind. If building occupants are open to adding or removing layers of clothing at home with the varying seasons, an even more significant amount of energy can be saved.
Constructing a sustainable family house that takes care of all its energy needs whilst keeping the carbon footprint to a minimum is not a new idea. Many vernacular examples work according to this principle when not too long-ago, air-conditioning was expensive and a rare commodity. Fortunately, there is resurgence in the development of architecture that has a connection to nature, considers seasonality, environmental factors, the sun’s position, natural shade provided by the surrounding vegetation and topography to create comfortable and energy efficient homes. Though time consuming, it’s better to spend more time incorporating these key sustainable elements in the early phases of tube project’s design. This is far less costly than making changes in the field post construction. Combining bioclimatic design with modern contemporary aesthetics and the specific requirements of individual home owners presents a challenging task for the best of designers and architects, but comes with a multitude of benefits for the home owner and the planet
Source – www.rodriguezgil-arquitecto.com
Suraksha Acharya has a master’s degree in sustainable design from the Architectural Association (UK) and is a cognitive member of the sustainable architecture field in India, championing the need to build better and more environment friendly structures. She is the founding principal of Midori Architects – a multi award-winning firm based in Chennai offering architecture, interior, landscape & master-planning services. www.midoriarchitects.com