Breakthrough made in the field of Thermal
Energy Storage (TES) system
technical breakthrough made in the field
of TES system are listed below
Enhancement in thermal conductivity of PCM
a) 15 % enhancement in Water based PCM with
Multi Wall Carbon NanoTubes (MWCNT) (For
b) 40 to 45 % enhancement in liquid paraffin
based PCM with MWCNT (For Free cooling application).
c) 12 % in liquid state and 56 % in solid
state of water with Graphene nanoplatelets
(For CTES application).
d) 22 % in liquid state and 29 % in solid
state augmented in commercial paraffin with
MWCNT (For Solar air heating).
1. Kumaresan V, R Velraj, SK Das. Heat and
Mass Transfer 48 (8), 1345-1355,2012
2. Kumaresan,V R Velraj, M Nanda, AK Maini,
Proceedings of ICFMD 2011. Organized by
DRDO [Received BEST POSTER AWARD]
Reduction in Subcooling
a) Subcooling reduction of 1.5°C in
water by addition of surfactant.
b) Subcooling reduction of 2.19°C in
RT 20 with respect to the heating/cooling
c) Subcooling reduction of 4°C in water
by addition of MWCNT.
d) Complete elimination of subcooling in
water with pseudomonas.
e) Subcooling reduction in RT 20 with respect
to radial location.
1. P. Chandrasekaran, M. Cheralathan, V.
Kumaresan, R. Velraj. Energy Vol 72, 636–642
2. GR Solomon, S Karthikeyan, R Velraj.
Applied Thermal Engineering 52 (2), 505-511,
Solidification & Melting Characteristics
90 % reduction in solidification time
at the cost of 20% reduction in storage.
b) 25 % and 20 % reduction in solidification
time of water with MWCNT and CuO respectively
c) 33 % reduction in solidification time
of RT 20 (Free cooling) with MWCNT.
1. R Velraj, R.V. Seeniraj, B Hafner, Christian
Faber, Klemens Schwarzer. Solar energy 65
(3). 171-180. 1999
2. P Chandrasekaran, M Cheralathan, V Kumaresan,
R Velraj Energy 72, 636-642, 2014
the generalised H-T relationship that accommodates
the materials having either constant or
a range of phase change
TES applications. This simplified the solving
procedure by numerical methods for phase
b) Applicability of different mathematical
models for the PCM based packed bed storage
system – (Mapping).
c) Introduced Computational Fluid Dynamics
model for Phase Change Material based free
1. R. Velraj, R. V. Seeniraj, B. Hafner,
C. Faber and K. Schwarzer.. Solar
Enegry Pii: S0038-092x (96) 1999
2. S. Karthikeyan, R. Velraj International
Journal of Thermal Science. Vol.
60, 153-160. 2012.
Technical contributions made in various applications
a) Free cooling of buildings
cooling is one such concept through which
building cooling demands can be met without
compromising the indoor air quality. Our
research group have been doing work in free
cooling of buildings for the past 10 years.
Further I have guided two Ph.D. research
scholars who have completed their doctoral
work and presently guiding two research
scholars who are carrying out their research
work in this particular application. We
have achieved year round thermal management
in a building using double layered PCM.
b) Cool Thermal
Energy Storage System
Energy saving potential of 6 % – 9
% that leads to reduction in the chiller
capacity by operating the evaporator at
higher temperature (CTES).
c) Solar Air Heating
Solar air heater (SAH) is one of the promising
solar thermal technologies which could be
used for low and moderate temperature applications.
The nominee has research experience in the
field of solar air heaters. Interesting
results were also obtained from the experiments
conducted by our research group. It
is also revealed that fluctuation of hot
air in the solar air heater could be minimized
through integration of TES system using
HS 58 as PCM.