Bioclimatic Design and Passive Solar Systems

The building sector is responsible for almost 40% of the total final energy consumption on a national level. This consumption, either in the form of heat (using primarily oil) or electricity, besides being a significant economic burden due to the high cost of energy, results in large scale atmospheric pollution, mainly carbon dioxide (CO2) which is responsible for the greenhouse effect.

The reduction of energy consumption in buildings can be achieved by simple methods and techniques, using a appropriate building design (bioclimatic architecture) and energy efficient systems and technologies, such as passive solar systems.

Bioclimatic architecture and what bioclimatic design includes

Bioclimatic architecture refers to the design of buildings and spaces (interior – exterior – outdoor) based on local climate, aimed at providing thermal and visual comfort, making use of solar energy and other environmental sources. Basic elements of bioclimatic design are passive solar systems which are incorporated onto buildings and utlilise environmental sources (for example, sun, air, wind, vegetation, water, soil, sky) for heating, cooling and lighting the buildings.

Bioclimatic design takes into account the local climate and includes the following principles:

• 
  

Heat protection of the buildings in winter as well as in summer, using appropriate techniques which are applied to the external envelope of the building, especially by adequate insulation and air tightness of the building and its openings.

Use of solar energy for heating buildings in the winter season and for daylighting all year round. This is achieved by the appropriate orientation of the buildings and especially their openings (preferably towards the south), by the layout of interior spaces according to their heating requirements, and by passive solar systems which collect solar radiation and act as “natural” heating as well as lighting systems.

Protection of the buildings from the summer sun, primarily by shading but also by the appropriate treatment of the building envelope (i.e. use of reflective colours and surfaces).

Removal of the heat which accumulates in summer in the building to the surrounding environment using by natural means (passive cooling systems and techniques), such as natural ventilation, mostly during nighttime.

Improvement – adjustment of environmental conditions in the interiors of buildings so that their inhabitants find them comfortable and pleasant (i.e. increasing the air movement inside spaces, heat storage, or cool storage in walls).

Ensuring insolation combined with solar control for daylighting of buildings, in order to provide sufficient and evenly distributed light in interior spaces.

Improvement of the microclimate around buildings, through the bioclimatic design of exterior spaces and in general, of the built environment, adhering to all of the above principles.

Passive systems for heating – cooling and lighting

Passive solar systems are the integrated parts – elements of a building which function without mechanical parts or additional energy supply and are used for heating as well as cooling buildings naturally. Passive solar systems are divided into three categories:

• 
  
  Passive Solar Heating Systems


• 
  
  Passive (Natural) Cooling Systems and


• 
  
  Techniques Systems and Techniques for Natural Lighting
  

The bioclimatic design of a building requires the simultaneous and coordinated operation of all the systems so that thermal and visual benefits can be combined throughout the year.

Important to remember

1. 
   
   Buildings are intensive energy consumers, thus contribute significantly to the greenhouse effect and climatic change, and have a severe overall environmental impact.


2. 
   
   As inhabitants of buildings, we can make our lives more comfortable, preserve the environment, our health and well being. We can use them appropriately to this end.


3. 
   
   The energy we consume in buildings is costly. It is worthwhile asking ourselves who pays for this consumption and why.


4. 
   
   All of us affect the energy performance of the buildings we live in. If we are aware of proper design, materials and use of technologies, we can apply them as far as possible in each case. Every action, even the simplest, can have energy benefits for our building.


5. 
   
   The sun heats buildings. We can make use of this knowledge for passive heating by ustilising bioclimatic design strategies.


6. 
   
   Buildings should be protected from cold and heat using suitable insulation.


7. 
   
   Just as we protect ourselves from the sun in the summer, so should we protect the buildings we live in.


8. 
   
   Natural cooling, compared to air conditioning, not only provides energy saving, economic and environmental benefits, but also constitutes a different approach, having as its goal, human comfort and well-being.


9. 
   
   We can utilise natural resources, and also reduce the internal loads of buildings accordingly.


10. 
    
    We can utilise daylight, but we must understand and solve the problem of glare.


11. 
    
    Buildings must function rationally in order to ensure the efficiency of passive systems and energy saving techniques. We should not forget to open and close windows and blinds appropriately.


12. 
    
    We should not forget that energy consumption causes environmental degradation. In contrast, bioclimatic, energy efficient buildings improve the quality of life for their users.