Value of Passive Solar Heating & Cooling Structures in the 21st Century

Passive Solar Heating


The rate of expanding population growth with increasing inventions in the field of industries and technologies has all together resulted in the increasing energy consumption enormously. This high consumption of resources is a concern for sustainability. The constant use of limited fuels and resources hurts the environment and energy conservation. Passive solar heating and cooling structures are an innovation in the field of architecture and construction that would perform with the existing energy. 

Passive Solar Architecture is a way of designing buildings that takes advantage of the benefits of the local environment while minimizing the adverse impacts of the climate. Passive Solar Architecture is an innovation in building construction without exploiting any additional mechanical or electrical sources called the passive solar building design concept.

What are Passive Solar heating Structures? 

Passive Solar Heating
Passive Solar Buildings

Passive solar buildings use solar energy for their energy needs in different seasons. The concept of passive solar structures, performance, and benefits. The primary concept of passive solar buildings is that the structural elements, i.e., the windows, walls, and the floors, are developed with the ability to collect solar energy, store them and utilize it later. This energy is then used in the winter for warmth and used to reject the heat during the summer or winter seasons. A “passive” building on account of its influence from natural energy resources to sustain a comfortable temperature.

Different Aspects of Passive Solar Heating and Cooling Structures

Passive Openings

Passive cooling is generally used to avoid overeating and for that, ventilation and window placement play a crucial role. Passive Solar buildings often do not have an active cooling system, and several design measures are incorporated to reduce the summer heat load. Venetian blinds are manually adjustable by the users and were placed outside the glazing to reduce direct solar gains. Passive openings also are a way of orienting the openings towards the maximum sun intake side like the South side in regions like India or equator regions.

A picture containing sky, outdoor, road, buildingDescription automatically generated
Source: AIR house

Passive Openings in proper shading techniques can be used to reduce unwanted heat absorption in summer, all openings could be shaded by an overhang, awnings, shutters, pergolas, jallies, and trellises. Passive openings should be placed in such a way that it manages the wind, and buoyancy affected by air temperature differences creates air pressure variations throughout inhabited spaces. Passive heating should be accompanied by suitable shading of windows to allow maximum winter solar gain and prevent excessive solar gain, causing overheating during summers.

Direct Sunlight or Energy Storage

Passive solar buildings are intended to let the stored heat into the building during the winter months and restrict the direct sun during warmer days. This could be attained by passive solar design elements, such as shading, incorporating large south-facing windows, and building materials that absorb and release the conserved solar energy.

direct sunlight

Direct passive solar system, the interior space acts as a solar collector, heat accumulator, and distribution system. South-facing glass admits solar energy into the house where it strikes masonry floors and walls, which absorb and store the solar heat, radiated back into the room at night.

Passive storage processes or simply collecting heat from the sun during daylight hours and distributing the heat once their surroundings cool. Sensible heat storage materials undertake no change in phase over the temperature range contended within the storage process and store thermal energy by sensible heat in solid or liquid materials like water, concrete, and many other materials that are useful for storing heat.

Indirect Sunlight or Trombe walls

thermal mass

Thermal mass absorption as Trombe walls is a way of indirect sunlight. When the sunlight strikes these walls and transfers them to the space by conduction. A Trombe wall accumulates heat in winter and can discharge the heat in summer and can act as a supplementary temperature monitor. 

Trombe walls are installed in structures to passively heat the building. The installation of Trombe walls could also decrease the requirement to heat the buildings. A conventional Trombe wall comprises a thick masonry wall layered with dark, heat-absorbing material and faced with either a single or double layer of glass.

Economical and Eco-friendly materials

economic materials

Many economical materials are used to absorb heat from the sunlight during the heating season and absorb heat from warm internal air during the cooling season. AAC blocks or Autoclave Aerated Concrete (AAC) blocks are widely used as an alternative to red bricks and made from locally available materials like cement, sand, lime, water, and additives. There are many other materials like volatile organic compounds or VOC Paints, Low emissivity glass, and wood waste products such as sawdust, wood chips, wooden shavings, etc.

Few Examples of Passive Structures

The Energon Office building, Ulm, Germany

passive office building

The Energon passive office building usually conjures up images of artificially heated or air-conditioned rooms where the air is stale and the light harsh, an architectural innovation that’s changing the image of the sterile workplace. 

The Energon passive office is a triangular, compact building with five stories, and has a physically curved facade enclosing a glass-covered atrium at the center. This provides ventilation and daylight. The building is a reinforced concrete skeleton construction with facades made of prefabricated wooden elements of largely equal dimensions.

Green School South Africa 

green school

Green School was built in the Western Cape of South Africa, the Green School must deal with cold winters and hot summers. The school building attains this by inculcating passive heating and cooling principles that work hand in hand. The buildings are constructed from locally sourced shoved earthly use thermal mass to warm the classrooms during colder seasons. The school also makes full use of the solar heat absorbed, capturing this heat inside warms up the room.

Sunlighthouse by Juri Troy Architects

A house with solar panelsDescription automatically generated with medium confidence
Source by Adam Mørk

The Velux Sunlighthouse in Pressbaum near Vienna is a house in Austria and was completed in October 2010. Sunlighthouse utilizes the maximum solar potential as well as efficiency. The highly pitched roof maximizes solar exposure by hosting three technologies, a grid of skylights, rows of solar thermal panels, and a 48-square meter solar array for electricity that make full use of the sun.

Cowboy Modern Desert Eco-Retreat, Jeremy Levine Design

Jeremy design

Cowboy Modern Desert Eco-Retreat is built in San Bernardino’s High Desert. Cowboy Eco-Retreat utilizes a passive solar design to keep warm during cold nights and a cooler environment during the day. The Eco-Retreat was designed with a zero-waste system; the light steel columns and beams were manufactured off-site and assembled on-site.

The passive cooling and heating in the house are achieved by using thermal mass in the walls and concrete floor. Additionally, overhangs prevent direct sunlight from entering the home, keeping it cool during the day, this also prevents the house from overheating during the night as well as the day. The roof overhangs form a covered wrap-around deck equally big as the house for indoor and outdoor living spaces.

The Solar XXI building in Lisbon, Portugal


The office space is on the south side of the building to take advantage of daylighting and solar heating. The spaces with occasional use like laboratories and conference rooms are on the further side of the building. The Solar XXI building’s main façade, South oriented, is covered by windows and PV modules of equivalent proportions. This large glazing area interacts directly with the office rooms permanently occupied, collecting direct solar energy.

Passive Solar Heating Building, Leh 

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The Passive Solar heating buildings in Leh were created to create naturally heated houses and spaces. In less privileged areas like Leh, where the resources are so limited, passive solar houses have been very useful. These hoses have been made using eco-friendly materials like clay, and straw waste, which was made into lightweight blocks to create the basic building unit. The orientation of these houses also plays a role in keeping the house warm without the use of fire or electricity. With a Southside orientation, the houses can absorb the maximum heat during the winters. 

Passive heating solar houses are economical, embedded with no-cost batteries, and made from plastic reused water bottles to store solar energy during the day. Passive Solar houses don’t only take advantage of the solar energy to preserve heat but various insulation materials to layer the walls as well as the flooring, like wood waste and wool which is available in a surplus amount in Leh.


The rate of increasing population growth with increasing innovations in the field of industries and technologies has all together resulted in the increasing energy consumption and there is an urgent need to incorporate a new way to resolve the issue. Passive solar heating is an age-old concept that we can use in current structures and buildings, by implementing simple elements like passive windows, shading devices, and insulation, to make buildings even more energy-efficient. Studies on passive solar buildings with more architectural and aesthetic conceptual approaches must be implemented more. Commercial buildings like schools and malls have an ideal space for the passive solar building design concept. 

The passive solar building system is an innovation that is still in its developing stage and still could cause damages like overheating or perception of the society towards concepts. The use of passive cooling and heating can help to decrease the carbon footprint and turn dwellings into an eco-structure. The only solution for this is public education and awareness.

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