Bioclimatic Interventions

The term ‘bio-climatic’ means ‘of, or pertaining to, the relationship between living things and climate’ (Merriam- Webster Dictionary). It was first used in terms of design in the early sixties by Victor Olgyay in his famous book ‘Design with climate: bioclimatic approach to architectural regionalism’; where he pointed out to the need for considering climatic factors in designing spaces that would be thermally comfortable for their occupants. He also developed the bioclimatic chart, based on the dry-bulb temperatures, wind speeds, and relative humidity values, in order to identify the limits of the human comfort zone (Figure 1). He pointed out that if climatic conditions are determined to be outside the comfort zone, then corrective interventions are needed (Olgyay, 1963).

During the past few decades, when the effects of climate change started to be felt, the terms sustainable design and passive design started to gain popularity in the realm of architectural design (Watson, 1989). It is a widely accepted fact that climate change is the result of increasing greenhouse gas emissions in the atmosphere, which are produced by the increasing consumption of fossil fuels. This state of affairs is manifesting itself in the form of global warming; hence, there is a need to decrease energy consumption or change the type of energy resources to mitigate the risks of global warming (Xu, Huang, Liu, & Zhang, 2016). It is also an established fact that energy consumption has been increasing not only due to economic growth and developments but urbanization, and building construction (Ran & Tang, 2018). The building sector accounts for a significant part of the total energy consumption and produces at least 35% of the total greenhouse gas emissions (Mohammadi, Reza, Tahbaz, & Nasrollahi, 2018). This situation is creating an energy crisis as well as unusual weather conditions because of climate change (Frank, 2005). Consequently, the demand for thermal comfort is increasing further and in turn, increasing the amount of energy required to provide the increased space heating in winter and space cooling in summer (Li, Yang, & Lam, 2012).

Bioclimatic interventions are based on reducing energy needs while providing thermal comfort also, by using passive design principles. They can help enhance thermal comfort, thus reducing and balancing heating and cooling demands in buildings (Tejero-González, Andrés-Chicote, García- Ibáñez, Velasco-Gómez, & Rey-Martínez, 2016). Gonzalez and et al (2016) point out that traditional passive design methods are more sustainable practices instead of the current generic techniques. It goes without saying that vernacular architecture that is based on passive design principles is the result of bioclimatic design concerns. For thousands of years, people have used environmental factors to obtain the best solutions for providing thermal comfort within (Canas & Martín, 2004). These vernacular methods have varied depending on site conditions, location, climatic conditions, local materials, and cultural norms.

Bioclimatic architectural interventions are related to weather conditions being in the comfort zones or not. If the conditions are outside of the comfort zone, architectural interventions are needed (Manzano-Agugliaro, Montoya, Sabio-Ortega, & García-Cruz, 2015). The most productive and efficient conditions for human beings are also defined as their comfort zone, which is based on visual, acoustical, psychological and thermal comfort limits; but the key one is thermal because without optimization of thermal balance, comfort conditions cannot be fulfilled, and human beings cannot be productive. Major factors that affect human comfort in buildings are air temperature, radiation, air movement, and humidity (Olgyay, 1963) and these can be optimized through bioclimatic design strategies.

While Watson (1989) defined the bioclimatic design strategies as minimization of conductive heat flow, infiltration, external airflow and solar gain, promotion of solar gain, ventilation, radiant cooling, and evaporative cooling, and providing thermal storage, Canas & Martín (2004) specified the strategies as being high thermal mass, protection against solar radiation, rain, wind and cold temperatures, usage of solar radiation and natural resources, proper building form and town planning.

On the other hand, building performance simulation (BPS) tools enable designers to optimize thermal comfort and energy consumption in their buildings. For instance, BPS tools are used to predict the thermal behavior of buildings in the ensuing environment, simulate the impact of daylight and artificial lighting inside buildings, calculate of the effects of various building materials and components and estimate the capacity of equipment for thermal and visual comfort (Aksamija, 2015). However, obtaining realistic design alternatives require detailed analyses of different energy types and environmental inputs. In addition to that, materials, including structural materials, are also critical issues for analyzing and optimizing the building’s performance (Danatzko, Sezen, & Chen, 2013). When implementing successful bioclimatic interventions and realizing a sustainable design through BPS, it is possible to not only show different alternatives of designs for clients but also to compare these alternatives for their energy efficiency and economy.

It should be pointed out that energy efficiency has become more important not only due to the concerns for depleting energy resources but also the impending effects of climate change that are expected to trigger global disasters. Since buildings are one of the major consumers of energy resources in the world, there is a dire need to focus on minimizing the use of energy based on fossil fuels and when possible, to replace them with renewable and harmless energy resources. In order to achieve this goal, adopting and implementing bioclimatic design approaches on the building scale and as well as the urban scale has become imperative.

The beauty of most of the bioclimatic principles is that they can also be applied to existing buildings in order to improve their performance and convert them into environmentally conscious ones. To this end, BPS tools can be used to model the status quo of the buildings first, and then various bioclimatic features can be integrated one by one into the building model to predict their impacts on indoor visual and thermal comfort, and energy use for lighting, cooling, and heating. The cost and environmental impacts can then be compared for each intervention or combinations thereof; an optimized building renovation design may be achieved.