The concept of massing for maintaining thermal comfort in hot and dry as well as composite climates has been used across the world in vernacular architecture. Pooja Dawalkar who visited Jerusalem recently writes about how the city has been using the technology of massing of walls.
We cannot control the heat gained from the sun via radiation, but we can design our structures, fenestrations and landscape in such a way that the walls of the structure are well shaded at most of the times during summers, thereby reducing the impact of heat gain due to direct radiation on them.
In a Composite climate, the summers are very hot and dry and winters are very cold, it is therefore desirable to make houses as airtight as possible to avoid unwanted heat gain or heat losses due to convection. Hence the use of small windows, jali’s and ventilators located at height can be commonly seen in the traditional structures in this climate.
Reference of Construction details in the city of Old Jerusalem
One of the best ways to reduce heat gain or heat loss from the structure through walls is by increasing the mass of the walls. Thicker the walls more time it would take for the heat to travel from one face of the wall to other. The speed with which heat travels also depends on the material with which the wall is made. More the material resists the heat transfer, lesser the quantity of heat that shall pass through the material.
Higher the Thermal resistance i.e. “R”, lower shall be the heat transfer coefficient of that material, i.e. “U” value, lesser the U value, better the insulation and lesser the amount of heat loss or heat gain through the said material.
One of the best examples of this technology of planning and construction can be seen in the city of old Jerusalem.
The city has a very compact planning, with most of the walls being shared walls having thickness of around 600mm.
The compact planning also ensures that the streets and entrances to the houses are shaded by the surrounding structures for most part of the day there by reducing the chances of heat gain even on the streets.
maintaining the thermal comfort within the houses and streets of Old Jerusalem city both in hot summers as well as cold winters.