Measures taken before construction

• Heat storage walls are used for heating indoor spaces.
• A wall is placed between the living space and the glazed exterior such that solar radiation does not enter the living space but is collected, absorbed and stored. The glazed exterior reduces heat loss.

• A Trombe wall is a heat storage wall made of materials like concrete or bricks.
• The external surface of the wall is painted black to increase its absorption.
• Heat loss through the glass can be reduced by venting the storage wall at the top and bottom.

• Water walls work on a similar principle as Trombe walls.
• It is made up of drums of water stacked up behind glazing and painted black on the outside to increase the absorption of heat.
• Water is employed as the heat storage material.

• Transwall is a heat storage wall that is semitransparent in nature.
• It consists of a container made of parallel glass walls with a partially absorbing plate at the centre and water or any other liquid on both sides of the plate.
• It absorbs a part of the sun's radiations falling on it and transmits the rest.
• The transmitted radiation directly heats and lights the building while the absorbed heat is transferred into the living space.