A natural system that enables the heat transfer from the sun to different spaces of a building like the living room, dining room, etc.
It is defined as the glazed structure or room that can be used to capture the sun’s energy to heat the buildings.
A system that uses a solar collector to capture the heat and then spread through spaces by natural convection.
Indirect Gain System
A masonry wall used to separate the glazing from the living space, this masonry wall acts as a heat storage medium.
The Common Point
State Bank of Patiala, Solar Energy Centre, MNRE, MLA’s Hostel in Shimla, Panjab Energy Development Agency, TERI Retreat, Gurgaon and West Bengal Renewable Energy Development Agent Building at Kolkata – These buildings have one thing in common (apart from being in India) that all of them have solar passive design features. The designs of solar passive buildings are derived from traditional Mughal architecture. It is an ancient knowledge that finds it’s relevance in the Red Fort at New Delhi and forts and Havelis in Rajasthan (primarily in the cities of Jaipur, Jaisalmer, Jodhpur)
The main difference between modern architecture and solar passive design is the way one uses Nature. Modern architecture emphasises on constructing its own space by ignoring the elements of the Environment while the latter focuses on a balance between ‘own space and nature’.
Concepts of Climate Conditions
Six climate conditions are observed in India that are represented as “condition” (Mean Monthly Temp °C, Relative Humidity in %)
Hot and Dry (>30, <55), Warm and humid (>30, >55), Moderate (25-30,<75), Cloud and Cloudy (<25, >55), Cloud and Sunny (<25, <55), Composite (When six months or more do not fall within any of the others).
These climatic conditions must be considered while designing solar passive buildings. According to National Building Code (2005, NBC) the two climate zones “cloud and cloudy”, and “cloud and sunny” have been categorised under one common category “cold” – so now five climatic conditions must be considered for solar passive design. The climate zone or location where the building lies plays an important role as some elements of climate (solar radiation or ambient temperature etc) can be used fruitfully and to achieve the target of an energy conscious building.
Major Design Strategy
All the buildings constructed in the hot and dry, warm and humid and moderate zones must have a light interior colour of the walls, proper orientation of doors and windows, suitable sized overhangs for windows, good insulation of interiors. This would resist heat gain and promote heat losses in all buildings.
All the buildings constructed in the cold climate zones should have larger windows on the southern walls and dark exterior colours to absorb more solar heat.
Concept of Direct Solar Passive System
It is the simplest solar passive system as it allows the entry of solar radiation through the South facing wall. The thermal conductivity of the construction material stores and releases the heat for warming the rooms.
Concept of Indirect Solar Passive System
The admittance of solar energy through indirect modes, using a system such as
- Trombe Wall (Indirect gain solid mass walls).
- Roof Pond (A body of water, roof pond) located in the roof.
- Thermosiphon (capture and spread of solar radiation).
Concept of Passive Cooling System
The main principle of this system is to prevent heat from entering the building and release it when it has entered the building. Here are some techniques to achieve a passive cooling system –
- Light-colored roofs and walls to reflect heat.
- Properly designed shades and proper shading of windows.
- Correct placement of windows.
- Use of thermal mass to prevent overheating in hot, sunny weather.
- Night-time ventilation.
- Use of insulation.
Why Solar Design
These are some techniques that can be used by an Architect, Civil Engineer or a homeowner to make the building ‘energy conscious’. This would not only help the Environment but it will also reduce your dependency on the electrical cooling gadgets and it would help in increasing the efficiency of the artificial cooling systems. It will save you some money and unnecessary repair work.
People, let’s go Solar! Remember, together we can and we will Save the Environment.
SOURCES: Basic principles of Solar Heating and Cooling of Buildings, IGNOU