PMAY Affordable housing challenges
Design and cooling, using the wind
Pradhan Mantri Awas Yojana (PMAY) is an initiative by Government of India in which affordable housing will be provided to the urban poor with a target of building 20 million affordable houses by 31 March 2022. Without exaggeration this is the single biggest government program in the history of the planet. How to handle this awesome social task? Working with brave clients to tackle the task, RBTA has designed and is building the most advanced projects of this kind in the country. This project in Kolkata is a fine example.
Design of optimal PMAY Units
Kolkata, a city known for tropical summers that are hot and humid with temperatures between the low 30's and maximum temperatures often exceed 40 °C, and winters that tends to last for only two and a half months. This requires PMAY projects in Kolkata to take climatic conditions as the main design driver.
The architect has to design at the same time, from the inside to the outside, and vice-versa, from the exterior to the interior, efficiently shaping both exterior community space as well private apartment space, both working together to intelligently use natural cooling to maximize comfort. The use of the ''venturi effect'' is essential.
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a shaft. The patios in our buildings have been designed as vertical shafts that ventilate the interior common areas, through which the wind is choked and then propelled with cooling energy into the units, and vice-versa, into the gardens, helping to naturally cooling down both the interior and exterior space.
It is essentially about looking at design in volumes, to force the wind to move into a narrow opening and expand into a larger volume, the effect can be quite incredible. This design strategy creates what is referred to as wind tunnels and keeps the living spaces cool and airy. In fact, this idea always works irrespective of the predominant wind direction. Cross ventilation involves both urban scale and unit scale openings that allow breezes into the building areas and into the garden space. Using air movement and ventilation effectively, we can cut down energy needs, cutting in half our carbon-footprint.
Landscape design for cooling,
The units are crafted to be functionally attractive, spacious within the given PMAY parameters (3BHK 60 m2, 2BHK 50m2, 1BHK 35m2) and perfectly cross-ventilated. In the Units themselves, windows on the opposite side of the interior spaces, lets potentially stagnant air to be flushed out. This strategy creates continuous air movement in a space, independent of its scale. This cooling effect works at the Master Plan, Building and Unit levels.
Building envelopes for PMAY projects
Landscaping is an effective design tool for cooling. For example, extensive use of local trees minimizes heat around buildings. Placing a green canopy of trees along the southern and western faces of the buildings provide shade and heat reduction in the summer. Water bodies placed strategically prevailing wind direction, makes the wind move over the water bodies onto the exterior and interior living spaces, bringing in gushes of cool breeze.
It is no secret that industrialized building systems (concrete cast in place with aluminum form-work) provide speed to the urgent target of building 20 million affordable houses. What else does it bring to the urban landscapes of India? Monotonous, machine-looking repetitive blocks with a total lack of humanity, which in many cases provide life-less suburbs. How to tackle this potential social disaster?
The envelopes of buildings must solve the double equation of creating both exterior space which is shaped to be ecological, comfortable and communal in spirit, and interior units and common areas that are functional, spacious and of course comfortable. Modern architecture has provided thousands of solutions to affordable housing. Most of them failed.
RBTA believes the exterior envelope – the facades are the walls of the exterior space – should have great variety, free-flowing compositions, and human proportions. This project is a good example. It provides well-designed building envelopes for affordable housing. This is one of the key elements to make PMAY not just functional. RBTA PMAY solutions are at the forefront of design thinking in the transformation of India.