Cooling the natural way
Summer is the time when people want cold water and air-conditioning but it is often said that the cold water from fridge is not good for health. People are advised to have water from mud pots which creates a natural cooling effect and is also healthy. The concept of mud pot and vessels is that is makes things cooler. The mud insulates it from heat and the porous nature of its wall around permits micro ventilation, letting the water seep through.
There are many commercial and residential flats in Chennai today. Traditional dwellings in rural areas were built with plain mud walls which insulates and local thatch roof which ventilates. Later on as materials changed, burnt brick walls and roof tiles were used to shelter the houses from heat and cold, though at a lesser degree compared to the vernacular style. This approach avoided non-local materials, structures were not monolithic and construction was not rock solid. Nowadays the buildings are built with thick cement and double layer of bricks which makes it look modern and attractive. The high density materials all around let out heat conductivity warming up the inside, and sealed off interiors result in warm air trapped inside. People end up feeling the heat in the house and end up using air-coolers and refrigerators. The belief that rock solid materials last long is a misnomer. Construction timber lasts for centuries and so does a wall with lime finish. We often say they ‘breathe’, which is a principle behind their longevity.
Sealing of buildings is considered to make them stronger nowadays but that is not entirely true. Majority of materials that we use today are machine made, with much higher density and lesser porosity than the natural or handmade materials that were used in the past. No wonder they perform rather badly during the seasons. Imagine designing with hollow materials like hollow clay blocks – they provide insulation thanks to the void inside, yet allow ventilation when built reverse with the openings connecting inside and outside.
In case solid bricks have to be used, they can be arranged as a cavity wall, either with full cavity or as in rat trap bond. Porous materials can be replaced by hollow core options, not only in the walls but also in the roof. Filler roofs and slabs with light weight cement blocks as inserts are two easy-to-do examples besides ventilated hollow roofs. Beyond the passive methods, only where need arises one may consider mechanical methods towards indoor comforts.