Passive Heating & Cooling System
PASSIVE HEATING SYSTEM
A passive heating system is a way for the building material to collect, store and distribute solar energy without mechanical or electrical energy, which is least expensive means of heating. It happens when the object striking with solar radiations absorbs the heat. It works effectively by windows oriented correctly and by installing high performance windows.
Parts of passive heating system
🅐︎. Aperture: It is the collector through which solar radiation enters the building.
🅑︎. Absorber: It is the dark, hard surface which absorbs the solar radiation after it passes through the aperture. It could be floor, masonry wall etc.
🅒︎. Thermal Mass: It is not the exposed surface to sunlight like absorber and it stores heat produced by sunlight.
🅓︎. Distribution: The circulation of solar heating can be in purely passive system but in some applications fans, ducts, blowers helps in distribution process.
🅔︎. Control: This prevents the building from unnecessary heating during summer. For example roof overhangs can be used as shading aperture during summers.
Categories of passive heating system
🅐︎. Direct Gain Method
It is the simplest and cost efficient method where the space of the building is heated directly by sunlight.
🅑︎. Indirect Gain Method
The trouble wall or dark coloured heat collector is placed in front of a window directly in the sunlight, which is received by south facing wall.
🅒︎. Isolated Gain method
In this method the solar heat it is collected in a location separate from the space desired to be heated. Sunspaces/Solarium are the most common type of isolated gain heating system. Sunspace is a room designed to collect solar energy like in direct and indirect gain methods.
PASSIVE COOLING SYSTEM
A passive cooling system is a way to reduce heat or gain cooling without mechanical or electrical energy, which is least expensive means of cooling.
Some Passive cooling techniques
🅐︎. Shading
Shade the walls windows and roofs of the building from direct exposure to solar radiation. Can use overhangs on outside fascade of the building. Heavy insulated walls and roofs reduce the requirement of shading.
🅑︎. Wind Tower
Wind towers are used to create natural ventilation in the building, its function is to capture cooler breezes that prevails at higher level above the ground and to direct it into the building interiors.
🅒︎. Evaporative Cooling
Evaporative cooling lowers the air temperature by evaporating water, which is effective in hot and dry climate where the humidity is low. Some commonly used system are water sprinkler, water trough, shading trees etc.
🅓︎. Courtyard effect
Courtyard is an area open to the sky surrounded partially or wholly by the walls or buildings, which works on the principle of Stack effect.
🅔︎. Natural Ventilation
It is also called passive ventilation. It is the process of supplying and removing air from the interior of a building without using mechanical or electrical systems.
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