Radiative Cooling of Homes in South Asia for Thermal Comfort

Our project explores the feasibility of implementing a low-power, radiative cooling system to aid
the escalating demand for air conditioning in hot climates, particularly in South Asia. With
nearly two billion people inhabiting this hot and humid region, already strained electric grids are
now experiencing rolling blackouts when cooling is needed the most. Our proposed cooling
system uses radiative heat transfer to minimize energy expenditure while cooling the person.
The system consists of three parts to draw heat from the user and dissipate it into the
environment. The user’s heat first radiates to a colder “acceptor” panel, where it is then
transported via circulating coolant to the “emitter” panel. The emitter panel, covered by a
specialized material that selectively radiates heat while reflecting sunlight, then expels heat away
to the cooler environment. This process enables low-energy cooling below ambient temperature,
crucial for hot and humid climates.

After creating a comprehensive set of requirements to build a useful system, the team chose a
modular, inexpensive coroplast-based panel that can be used as both an acceptor, when painted
matte black, or as an emitter, when a film is adhered to the top surface. Tests were conducted to
measure the efficacy of each component in the system and to ensure that our user and
engineering requirements could be met.

These tests verified that the system could effectively cool the user. The team found that the
acceptor heat flux sits around 40 W/m2, while the emitter heat flux varied depending on weather
conditions (from just under 40 W/m2 in rainy conditions, to over 100 W/m2 in clear conditions).
With this data, the modular design of our panels can be leveraged to create a system that best fits
the needs of each dwelling it is installed upon.

Our results demonstrate the potential of this solution to mitigate the environmental impact of
traditional cooling methods while addressing the urgent need for thermal comfort in regions with
limited air conditioning access. Further work is needed to improve the current design by
determining the appropriate flow rate, pump size, and number of panels to best optimize the
system for the climate conditions in India. Nonetheless, this work shows that radiative cooling is
a promising and viable replacement to traditional air conditioning.