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Innovation stores solar heat using phase change material, reducing dependence
on electricity and conventional fuels for water heating
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Technology demonstrates 55 % thermal efficiency and can retain usable heat for
up to 12 to 14 hours after sunset
Pune: Researchers at MIT World Peace
University (MIT-WPU) have developed a solar thermal energy storage system that
enables hot water availability even after sunset by storing solar heat in a
phase change material (PCM)-based thermal battery. The technology addresses one
of the biggest challenges associated with solar energy—its intermittent
availability—and has the potential to reduce dependence on electricity and
fossil fuels for water heating applications.
Developed by Dr.
Anita Nene and Dr. Rohit Ghadge from the Department of Mechanical
Engineering, MIT-WPU, the system combines a Scheffler solar concentrator with a
thermal storage capsule containing paraffin wax, a phase change material
capable of storing and releasing large amounts of heat.
Unlike
conventional energy storage systems that rely on electrochemical batteries, the
proposed solution stores energy directly as heat. The system incorporates a
detachable PCM tube, a water-jacket heat transfer mechanism, and polyurethane
insulation to maximize heat retention and energy utilization.
According to
the researchers, the technology achieved complete thermal charging in
approximately 18 minutes and complete discharge in approximately 32 minutes
during laboratory-scale testing. The system continued supplying hot water after
solar input was removed, demonstrating its ability to provide thermal energy
beyond daylight hours.
The prototype
stores approximately 1.5 to 2 kWh of thermal energy and can maintain water
temperatures between 50°C and 60°C for up to 14 hours after charging. Compared
to conventional electric water heaters.
“One of the
major limitations of solar energy is that it is available only when the sun is
shining. Our objective was to develop a simple, cost-effective, and sustainable
thermal storage solution that can store solar energy and make it available
whenever required,” said Dr. Anita Nene.
“Thermal energy accounts for a substantial share of overall energy consumption. Technologies that enable efficient storage of solar heat can help reduce dependence on conventional fuels, improve energy security, and support the transition towards cleaner and more sustainable energy systems,” said Dr. Rohit Ghadge.
The
researchers conducted Computational Fluid Dynamics (CFD) simulations alongside
laboratory-scale validation to evaluate system performance.
The
technology is currently at Technology Readiness Level (TRL) 7 and is being
prepared for pilot deployments in real-world environments.
Potential
applications include residential water heating systems, hotels, hospitals,
hostels, educational institutions, industrial process heating facilities,
community kitchens, agricultural operations, and off-grid rural communities.
An Indian
patent application titled “Solar Energy Storage Capsule Using Phase Change
Material” has been filed under Application No. 202521118546. The researchers
are currently exploring collaborations with industry partners for pilot
deployment and commercialization.
“The next
phase of development will focus on field trials, performance optimization, and
scale-up for commercial deployment,” said Dr Anita Nene.
lower carbon
emissions by approximately 2.5 to 3 tonnes annually, contributing to India's
clean energy and sustainability goals.