Nanofluids helped TU Delft Solar boat team become world champions

Nanofluids: How did they they help the TU Delft Solar Boat Team Become World Champion? World champion TU Delft Solar Boat Team joined forces with YES-Delft start-up, Synano, to optimize the cooling system and win the 2019 Monaco Offshore Challenge.

The Delft University of Technology is well known for its successful student teams. These TU Delft Dream Teams are solely managed by the motivated students themselves. Every year with a completely new international and interdisciplinary team, they participate in competitions to put technical innovation on the map that contributes to a better future.

For 15 years the TU Delft Solar Boat Team pushed the limits in developing solar-powered boats. The goal of the team is to inspire the Maritime industry to explore green alternatives. The team was founded in 2005. In 2020 the team took the foundation in a new direction, they decided to explore the possibilities of hydrogen and decided to continue with hydrogen as their clean energy source. The foundation went through a rebranding and is now known as ‘TU Delft Hydro Motion Team’.

The 2019 team designed the first solar boat for open sea within the team. This boat is a trimaran and has three hulls. The boat is modular, which means it can be taken apart and assembled to be transported. With a sun deck of 28 square meters, this is the largest boat in the history of the team. In Monaco, the team became world champions in the ‘offshore class’.

The team implemented a new dual loop cooling system to cool the incredible heat generated by the drivetrain and battery. The cooling system is an uninterrupted cycle consisting of an open loop and a closed loop. The open loop contains continuously refreshed raw water, pumped in through inlets in the boat, while the closed loop is in contact with the hot components. Transfer of heat takes place between the two loops at a heat exchanger where the “cold” fresh water and “hot” coolant flow in counter current direction. The coolant rejects heat and moves on to repeat the cycle while the heated water is discarded, and new fresh water is pumped.

Nanofluids were employed as coolant in the closed loop which takes up heat from the motor, batteries, and other hot components of the electric solar boat circuit. Nanofluids are more effective in such a system compared to water because they have a higher thermal conductivity and therefore are able to transfer heat faster from hot components to the cold water loop. As the first Dreamteam to use Synano nanofluids, the team gained a lot of experience in handling the substance and analyzed tests to see how the fluid performs in real life. The team conducted inhouse tests to cool the battery pack with nanofluids and compared the performance with water cooling. The results of the tests are shown below in the figure. The nanofluids show improved cooling performance and the temperature curve is smoother indicating better heat transfer than in case of water.

Battery temperature- nanofluid cooling

In the sweltering temperatures of Monaco in July, the TU Delft Solar Boat team implemented the nanofluid coolant developed by Synano which, thanks to embedded nanosized particles in the liquid, demonstrated superior heat transfer capabilities compared to conventional water-cooling.

It was found that the overall average temperature of the motor remained well within the limit of 65°C when using nanofluids; and, when sudden power peaks occurred, nanofluids helped to maintain the temperature at the average (62°C) recorded and prevented a sharp increase in temperature. Nanofluids indeed show a faster response to changes in motor power and temperature compared to water. This is due to the fact that nanofluids possess a higher heat transfer coefficient than water, which makes the heat transfer faster and facilitates power ramp up and ramp down operations during the race.

Based on successful collaboration in 2019, the team worked again with Synano in 2020, however, due to COVID lockdown the races did not happen. Since then, the solar boat team has changed the energy source and rebranded as hydrogen boat team.

The team is looking forward to continue working with Synano in the future in order to optimize the cooling system and proving that innovations conjured up at YES-Delft can positively influence Dreamteams on the other side of campus.