Climate-Resilient Architecture: The Key to Combating Heat Stress in India
Global warming has increased the intensity of heat waves over the last few decades, and the increasingly unbearable weather has become a pressing public health issue in countries around the world. In India, heat waves are the second deadliest natural force after lightning, killing over 20,615 people from 2000-2020. This year, the observed daily average temperature for the pre-monsoon months – the peak of summer heat in India – was almost 4℃ above the baseline of 1981-2010 in many parts of the country, making the summer of 2022 the second hottest on record.
The growing frequency of these heat waves is significantly increasing the urgency of climate action. It’s also having an impact on India’s business sector, as people resort to artificial methods of cooling to battle the temperature spikes. This is leading to an increase in the sales of air conditioners as compared to previous years. Currently, only 13% of the households in India have access to air conditioning – but a 2021 study projects that this number is likely to grow to almost 70% in the next two decades.
This growing demand for air conditioning is not limited to India. According to a 2018 International Energy Agency report, while more than 90% of households in countries like Japan and the U.S. have air conditioners, only 8% of the 2.8 billion people residing in the world’s hottest regions have access to air-conditioning — making cooling an issue of accessibility and equity.
The Problem with Air Conditioning
However, the solution to this global challenge isn’t as straightforward as simply expanding access to air conditioning in countries like India. Extreme heat results in increased consumption of, and demand for, electricity, and in recent years, the sudden spike in electricity consumption caused by India’s heat waves has exceeded the country’s power supply, as illustrated by this summer’s shortage of coal, which has led to massive electricity outages.
This can result in a vicious circle, in which excessive heat leads to growing demand for air conditioners, which increases the demand for scarce power resources, forcing countries to turn to fossil fuels that, in turn, contribute to further global warming. Meanwhile, most low-income groups can’t afford cooling technology solutions such as air conditioners, even when they’re available on the market, nor can they afford the high energy bills that come along with these technologies.
With no access to cooling technology to counter the rise in temperatures, the people most impacted by this cycle are forced to endure an uninhabitable environment.
It’s becoming clear that cooling is no longer a luxury in today’s world – it’s a necessity for survival. It’s also becoming a new indicator of global inequality, as marginalized communities are the most affected. Below, we’ll explore some innovative technologies that can help address this growing need in the world’s hottest – and most economically vulnerable – countries.
The Impact of Heat-Resistant Architecture
Unsustainable growth in electricity usage isn’t the only drawback to the rising use of air conditioning. Even when electricity is reliable and accessible, widespread utilisation of air conditioning devices contributes to local temperature increases through a phenomenon called the urban heat island effect, since air conditioners produce heat during operation, and that heat is released back into the atmosphere. In light of the multiple drawbacks to greater use of air conditioning, alternative technologies are needed.
One promising alternative cooling solution is to employ heat-resilient architectural methodologies and to focus more on passive design strategies and cooler building materials when designing and constructing buildings. Passive design strategies focus on a building’s design and architecture (such as its floor plan or building materials): They are considered passive because they are not mechanized technologies (such as air conditioners/air coolers) which consume external power/energy.
When assessing which building materials to use in heat-resistant architecture, it’s important to take their broader environmental impact into account. Conventional high thermal insulation building materials, such as polyurethane foam and expanded polystyrene, have significant longevity and low thermal conductivity. (Thermal conductivity refers to a material’s ability to transfer heat. In the case of building materials, the lower the thermal conductivity, the better, since low-conductivity materials transfer less heat or cold from outside, assuring greater thermal comfort within the building during both summer and winter.) However, since they’re not biodegradable, these conventional materials are not environmentally friendly. That’s why the focus has to shift to other types of high-insulation building materials, which provide the same benefits in terms of longevity and thermal conductivity, but are also less harmful to the environment. Environmentally friendly high-insulation materials reduce dependence on mechanized cooling, thereby increasing the resilience of a building and its occupants to heat stress through non-energy intensive solutions.
But environmental impact isn’t the only factor to consider when determining which cooler building materials should be utilised in India. There are four factors that should be taken into account when identifying solutions that can meet the country’s unique needs. These materials should be: environmentally friendly, climate(heat)-resilient, both traditional and modern, and aspirational. But meeting these requirements is easier said than done.
Traditional Indian architecture features thatch roofs, which are environmentally friendlier than concrete – and much better insulators. But they are not aspirational, since traditional architecture has been on the decline in India since the 1990s, owing to globalization and the population’s aspirations for a Western lifestyle. This has led to the scaling of concrete and glass buildings – including skyscrapers. The increasing construction of skyscrapers has also been driven by the need to utilise vertical space, in response to the growing population and limited access to land. For obvious reasons, these taller structures must be built with steel and cement instead of the traditional earth blocks.
Innovative Building Materials Designed for the Indian Market
In light of these competing demands and shifting societal preferences, how can Indian architecture find a balance between building materials which are traditional, environmentally friendly and climate-resilient, like thatch roofs – and also aspirational, like concrete?
Three startups incubated by Villgro – Greenjams, Strawcture and Zerund – have struck a balance between traditional and modern architecture by developing building materials that are not only aspirational, but that also provide extreme thermal comfort within the building, keeping the temperatures cool and reducing dependence on mechanized, energy-intensive cooling. The following chart shows the thermal conductivity of these innovative materials, compared to that of some commonly used conventional building materials in India.
In effect, these startups are creating building materials which encapsulate all four of the key features mentioned above. The building materials they’ve developed are made from agricultural or plastic waste, making them environmentally friendly. Their thermal insulation levels are on par with (or better than) those of conventional AAC blocks or red clay bricks, making them climate- and heat-resilient. And their appearance and durability is similar to that of concrete, while they are often made from common crops grown in the country, making them both traditional, as well as modern and aspirational. Let’s take a look at these startups and their solutions in more detail:
- Greenjams: Greenjams’ objective is to create a beautiful, carbon-neutral built environment through material innovation. The company creates carbon-negative building materials from crop residues and industrial byproducts. Their flagship innovation, Agrocrete®, helps reduce the cost of construction by up to 50% and improves the building’s energy efficiency by up to 25%.
- Zerund: Zerund produces a building product known as Plastic Embedded Lightweight Bricks, which are made from recycled plastic waste. Industrial production of this sophisticated building material started in Guwahati, India in 2018.
- Strawcture: Strawcture makes its building material, AgriBioPanels, from the waste that’s left after a crop like wheat, rice, sugarcane or coconut is harvested or grown. These panels can be used as a building material for both walling and roofing.
All of these solutions are carbon negative, and they all possess low thermal conductivity. Furthermore, these climate-resilient building materials generate livelihoods for people at the bottom of the pyramid by employing waste collectors and farmers across the value chain — resulting in an increase in their income.
These are just some of the innovative solutions working at the intersection of modern and traditional architecture in India, to counter heat stress in a sustainable and environmentally friendly manner. As the world grows gradually – and perhaps rapidly – hotter in the coming years and decades, supporting innovative businesses like these will become an increasingly essential part of global efforts to mitigate and adapt to climate change.
Photo courtesy of Nick Kenrick.