For passive cooling of your home

Ventilated filler roofVentilated filler roof

The design behind ventilated cavity filler roof. By architect Sathya Prakash Varanashi

Global warming is happening much earlier than ever predicted, at which rate we may leave nothing for our future generations. While it is mandatory on all of us to reduce our consumptions, wastages, trash generation and such other measures, it is equally important to devise ways of comfortable living without depending upon energy and electricity.

Cavity roofs have been a part solution towards passive cooling, with embedding clay pots, hollow filler tiles and such others. However, during extreme summers even the hollow clay tiles are becoming less effective.

Heat gets transferred through conduction and convection, the former through solid materials and the latter through voids and spaces. When the building terrace receives direct sun rays, it gets heated up and starts to pass the heat downwards into the room below. Even the voids inside the hollow clay filler roof would let heat go through it, for this trapped air also gets heated with the surface heat being very high. In other words, the present day hollow clay filler roofs will let heat transfer through both the processes of conduction and convection, the void being a sealed one.

In case the trapped air inside the void which gets heated up is not sealed, but move across to let cool air in, then the heat transfer would somewhat reduce. This can be achieved by inserting a small length of electrical conduit pipe between the voids of the hollow clay filler blocks, which are embedded within the RCC roof.

Once all the blocks are in place, small length of pipes are inserted such that their ends are within the void of the filler block. It is not a continuous end-to-end pipe, which serves no purpose at all, but short connections between the voids. As the air inside the void gets heated up, it moves along the pipes to equalise the heat all over the filler block. At the edge block, this hotter air moves out of the block itself, while cooler air enters the voids from the other end.

Between the two outside edges of the slab, one would have breeze called windward direction and the other end will not have much air movement, called leeward direction. Air moves from windward to leeward directions, in the process pushing out the hot air accumulated inside all the voids of the filler roof. This would reduce the heat gain inside the room.

The ends are finished with slight bend to block rain water. Pipe pieces should not move so much that their end is within the tile gap which gets filled by concrete, in which case the continuous air movement will get blocked. All that the builder contractor has to oblige is let a few helpers insert the pipes, which is fairly fast. It’s a one-time investment of time and effort, to achieve passive cooling of slightly higher order.

The Hindu

Green buildings reduces operational expenses and improve the health and productivity of the residents

Think sustainable

While paving the way for sustainable development, green buildings not only reduce the operational expenses, but also improve the health and productivity of the residents.

The quantum of built-up area envisaged to be urbanised is simply humongous. Therefore, in order to extricate itself from the present scenario, India must follow the principles of sustainability. After all, the construction and operation of buildings have an enormous impact on the local environment, and also on greenhouse gas emissions.

“India has the highest growth rate of ‘building energy consumption’ in the world, so this concern is particularly pressing for corporates as well as for the government. To really tackle the challenge of making sustainable buildings, we need to rethink the way a building is designed and operated. Here, green buildings can surely offer a way to relieve the mounting pressure,” says Andrew Hines, co-founder, CleanMax Solar, a rooftop solar power development company.

See green, see life:

According to the Dodge Data & Analytics World Green Building Trends 2018 SmartMarket Report, India is expected to see strong growth in the green building sector with nearly 55 percent of all projects likely to pursue green by 2021.

So, what are the top triggers driving the green building activity? Firstly, the clients today (particularly the commercial tenants) are demanding green certified buildings, followed by increased awareness among homebuyers about the advantages green buildings have on the health of the occupants, and lastly, the governmental push and environmental regulations.

The choice is yours…

A green building stands on five main pillars – water, waste, energy, human experience and carbon footprint. So, in line with the growing trend of green building development, the focus on the usage of sustainable products during the construction stage is immense.

“Double-glazed glass is being extensively used by architects in the construction of buildings. So are water-efficient fixtures and energyefficient lighting. Components – free of toxic materials such as chlorine, lead, mercury, arsenic, chromium and cadmium – are also being frequently used by builders,” says GopalaKrishnan Padmanabhan, Managing Director –APAC and Middle East, Green Business Certificate Institute (GBCI).

Elaborating on the same line of thought, Harleen Oberoi, Senior Executive Director, Project Management India, Developer Projects Leader, South Asia, Colliers International, adds, “Blocks and concrete, which have a higher ratio of fly ash and blast furnace slag, are preferred by the developers.”

So, when it comes to finishes, “the objective is to use non-VOC emitting and anti-fungal alternatives in adhesives, paints, cladding, and carpets. With technology making big strides, light-weight precast concrete walls, fibre reinforced products as alternatives to conventional pipes, stray bales, compressed earth blocks, and other innovative building blocks for structural construct are also popular options.”

The way ahead:

According to the report (as mentioned earlier), 63 percent of Indian respondents said improved occupant health is the most important benefit of a green building. Additionally, respondents rated environmental reasons such as reducing energy and water consumption, and protecting resources. Therefore, experts believe that India is poised for an upward trajectory.

“Both developers and occupants have come to realise the benefits associated with green buildings. Sustainable products, which pass the acid test of having a positive impact on the environment, are being used in the construction of buildings. Not to forget, the demand by buyers for such buildings is high too,” concludes Padmanabhan.

Shehzin Shaikh, Times Property, The Times of India, Chennai

Go green, be seen to address pollution and global warming

Today, there is an urgency to address issues such as pollution and global warming. And with developers of the residential market pledging to build environment-friendly spaces, green homes are within the reach of home-buyers.

Eco-friendly buildings invite a lot of hype but there are also concrete advantages to ‘going green’ when you build them. From improving indoor air quality to mitigating global climate change, these buildings help people live a more resource-friendly and sustainable lifestyle. Keeping these important factors in view, the developers of the residential market have pledged to build environment-friendly spaces.

The green building concept has always been around. Our ancestors had conventional homes with baked red roof tiles and walls made of clay; energy-efficient structures that used to keep the house cool during summers and warm during the winters. Today, we have advanced technologies that create smarter systems to control lighting systems, power, inside temperature, water supply and waste generation. C Shekar Reddy, Chairman, CII-IGBC Hyderabad, said, “In the current degrading environmental scenario, the need of the hour is to design and construct green buildings and communicate their benefits to various stakeholders. Developers are becoming increasingly conscious of the changing environmental conditions and thus working in their capacity to reduce the carbon footprint at every stage of construction.”

Follow the rules

Change starts with an individual, and especially in cities, it is time to act. Kalpana Ramesh, environmentalist, interior designer, director of Kaava, says, “The process should start from following zoning rules in construction to obtaining the necessary legal permissions for sewerage and building within the FSI. People should stop buying apartments, offices and homes built on illegal ground even if it means at lower costs. Directly or indirectly, we are responsible for diminishing natural resources.”

Green homes within reach

Due to slightly higher cost, green homes are generally targeted at the upper middle class and luxury home-buyers. Property consultant Shridhar Rao says, “Among such buyers, awareness about the benefits of green buildings tends to be quite high, so acceptance of a sustainable way of life is also high. However, one cannot ignore the fact that there is still a lack of awareness about green building practices and its long-term benefits among a large section of Indian users. A majority of users are under the impression that green building practices are expensive and not financially-feasible. But even middle-class buyers are now environment-conscious and would not mind paying a higher price if the project’s benefits are explained. At present, amenities that are being offered by developers have been made mandatory under government regulations.”

Cost of a green home versus a normal home

Green buildings provide financial benefits that conventional buildings do not. Mayank Saksena, MD – land services and head – South India, ANAROCK Property Consultants, explains, “Green building practices can improve the environment’s ecology in numerous ways. They reduce energy consumption by 20-30 percent and water usage by 30-50 percent as well as significantly reduce waste generation by extensive recycling. Apart from the obvious protection of the ecosystem and biodiversity, the use of green building practices leads to better air quality, enhanced daylight (leading to lower electricity consumption), superior health and overall well-being.”

Industry experts are of the view that although the initial costs of a green building may be higher (up to 15 percent depending on various factors) than conventional buildings, there are many long-term benefits. Reddy explains, “Anyone buying a house should keep in mind that it will stand for at least 50 years or so. And even if, for a moment, we agree that the cost of the house increases, it doesn’t matter if you invest an additional amount because in the coming years, you would be able to enjoy benefits such reduced electricity bills, better comfort, and good health at lower operating cost. And the payback period is hardly two years. Also the incremental cost of these buildings has come down to about two to three per cent over a conventional building at present.”

Vibha Singh, Times Property, The Times of India, Chennai