PASSIVE SOLAR HOMES: BASIC BUILDING PRINCIPLES

Passive solar heating is not only applicable on family or individual houses, bud also on objects of different purposes. In the following list we will introduce ten basic principles for building passive solar home.

1. Choose a spot that is receiving sunlight from the southern side, without tall trees, hills or tall buildings. If you are not certain, visit the future construction site during winter solstice when the sun is at its lowest in the sky. Southern wall of the house must receive sunlight from 9am to 3pm. Bring a compass with you to determine in which direction south is. Regarding protection from the wind, the constructed object should with its longer side follow the direction of winter winds blowing. As additional protection it is recommended to plant a row of evergreen trees at the flank from where the wind blows.

2. Using systems of different inner or outer protections from the sunlight, when it is necessary, sunrays are blocked, and heat is prevented from penetrating inside. Choose a home design with as few shaded areas and porches on the southern side as possible. Shadows and porches prevent sunlight from entering the house and significantly reduce the efficiency. Porches on eastern or western side can prove useful because they shade windows from the summer sun.

3. Face the longest wall towards south. Southern glasses should have surface area of at least 7 percent of house area, and a maximum of 12 percent; over 12 percent would require additional shading during summer. You must also be cautious in while choosing the windows for the southern side, since they need to let the sunlight through.
4. Roof must be designed so it provides good protection from high summer sun, and not plaster entry of winter sun – properly designed shading is key factor to energetic efficiency of a passive solar home
5. THERMAL MASS – For the southern side, it is required to provide thermal mass, tiles, bricks, stone, or colored concrete walls – in order for them to absorb and emit heat. Especially parts of the house that receive direct sunlight during winter.

In a passive solar home during sunny winter days, it is warm enough and no additional heating is required. However, without heat accumulation, as soon as sun sets air would cool and the rooms would get cold. That is why gathered heat needs to be accumulated.

Heat is accumulated using thermal mass. In that purpose, dividing walls or floors are built from materials with high heating capacities. These are most often concrete, stone or brick elements. This way, even during nights and cloudy days, thermal mass radiates heat gathered during sunny days.

Thermal mass is also important during summer, because it absorbs heat from the rooms, making them cooler. It is important to let the air during the night cool the thermal mass and carry away the heat accumulated during the day.
6. DIGGING IN – Using soil as insulation and heat storage provides great benefits. Constant temperature below ground (around 12.2 degrees C) creates large energy savings for heating and cooling the space. None of the external influences like rain, snow or wind impact the building below ground level. Digging in only northern side of the object (especially if it fits the slope) provides protection from most disadvantaging impacts of cold winds, and object remains open towards south.

7. DOUBLE LAYER PRINCIPLE – Principle of “house inside a house” in terms of home construction, provides a zone for change of air inside these layers. That zone in between wrapper and the object is buffer zone, that mitigates all external impacts, provides insulation and decreases energetic requirements of internal object. This protective microclimatic membrane and passive solar gains of space create mild climate conditions as microclimatic environment in which given objects are placed.

8. GREENHOUSE – Hothouse or greenhouse as collectors-receivers of sun’s energy are fundamental elements of a solar building, that influence building’s energetic passive functioning. As insulation spaces they play the role of heat regulators. As heat collectors, they can be applied exclusively when oriented towards south or south-west.

9. GOOD INSULATION and adequately designed heating and ventilation systems are of immense importance for energetic efficiency of passive solar home. Besides elements for captivating energy, passive solar house or “self-heating” home is based on principles of saving energy. Taking care of heat conductivity and heat loss of all materials and entire building respectively, with maximum possible insulation of all elements (windows, walls, floors, ceilings) is one of the main requirements for this building concept.

10. NATURAL VENTILATION – It is very important to use principle of natural air flow, without additional consumption of energy for ventilation. System with openings at bottom and top façade, and its good positioning relative to direction north – south, in which the drift is at its strongest, a satisfying comfort is provided.

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