TNZ

https://youtu.be/6RDby_3CipI

https://youtu.be/GwQC_p4b93w

What exactly does it do?

Vnergy is a self-sustaining thermal energy storage system designed to survive the infernal conditions on Venus. Vnergy uses a thermodynamic approach to generate unlimited cycles of energy which can be utilised for long-term space missions.

Our solution makes use of the existing surface temperature and a heat sink powered by high speed wind currents on Venus. Heat energy from the Venusian atmosphere is absorbed by the graphene aerogel.

Via porous medium heat transfer, heat energy is further amplified and reflected in the pores of the graphene aerogel. This increases the thermal gradient and excites more electrons to flow across the terminal via the p-type and n-type semiconductors. Electricity produced will be stored in the graphene aerogel and discharged when it is needed. 

The temperature gradient will be achieved when wind currents cool the heat sink. The heat sink will be based on pin-type heat sink inspired by a high-emissivity porous carbon nanotube (CNT) forest which reduces drag and vortex shedding. This will facilitate more efficient heat energy dissipation. The entire energy storage system will have a zirconium nano coating which is highly resistant to high temperature and chemical corrosion by the acidic gases in the Venusian atmosphere.

Based on atmospheric wind speed at the surface level Venus at around 2.8 m/s, flow rate through the designed heat sink is estimated to be around 42.33m^3/h. CAD models were created using Solidworks and have a total estimated volume of around 3121cm^3 and estimated total mass of 3.5kg. Cooling efficiency of similar temperature and flow rate through previous experimental research replicating exhaust systems using carbon nanotubes as heat sinks has an estimated a cooling efficiency of 19-25%.

Challenges and limitations were faced when trying to calculate the electricity generated and self discharge rate. Insufficient data coupled with the lack of mathematical model was evident. Not only that, running simulations for the heat transfer inside the thermoelectric generator including thermal radiation and heat dissipation occurring in the heat sink due to natural convection has to be considered. Additionally, finding the thermal properties of lead terullide under extreme heat and pressure is also an essential.

The thermal energy storage system operates in Venus temperature, that is around 450 degrees celsius. The thermal battery will be rechargeable and has unlimited cycles as it operates based on a thermal gradient without the need of chemical reactions and mechanical parts. Hence, partial failure can be tolerated as energy can be stored in the graphene aerogel. The thermal battery can continue generating energy as long as there is a thermal gradient. 

Vnergy will land on Venus using a PICA aeroshell and a rocket assisted descent system. (RAD) . The aeroshell will act as a heat shield that protects the thermal battery during descent. Upon landing, spring-damper shock isolators will be deployed to reduce the impact.

How does it work?

1. N type semiconductor and P type semiconductor (lead telluride) are connected by copper metal.
2. Hot air from Venus’ surroundings enters a porous medium (graphene aerogel) which acts as a heat source/ storage.
3. The bottom end of the N type semiconductor is heated as heat flows from the heat source through a ceramic plate. The ceramic plate acts as a heat conductor and electrical insulator to prevent short circuits.
4. The upper end of the semiconductor is cooled by a heat sink made of carbon nanotubes powered by high speed wind on Venus to maintain the temperature gradient.
5. Excess electrons will move upwards to the cooler region of the N-type semiconductor.
6. The bottom end of the N-type semiconductor is now positively charged, while the top end is negatively charged.
7. Electrons then flow to the P type semiconductor via the interconnected metal.
8. The bottom end of the P type semiconductor which has a deficit of electrons will accept electrons and become negatively charged.
9. The top end of the P type semiconductor becomes positively charged.  
10. The flow of electrons from N type to P type conductor generates electric current.
11. Many p-type and n-type couples are connected electrically in series to generate a greater voltage. The couples are placed between two parallel ceramic plates. 

Diagram of Vnergy

CAD model of Vnergy

Graphene aerogel is used as heat source

Heat sink of Vnergy containing carbon nanotubes (CNTs)

What benefits does it have?

• Graphene aerogel is utilised to harness Venus’ high surrounding temperatures. Through porous medium, heat energy is stored for electricity generation. Stored thermal energy will last longer during the thermal discharging process.
• Pin-type heat sink inspired by carbon nanotube (CNT) forest to improve air flow and dissipate heat energy more efficiently
• No chemicals or active materials are involved in the process, making it less susceptible to parasitic reactions and degradation.
• Lack of mechanical, moving parts allows the energy storage system to weather shocks and vibrations experienced throughout its journey to Venus with ease.
• Use of TEG technology is highly compressible and less bulky.
• The system is also rechargeable, allowing it to provide an adequate supply of energy throughout the mission on Venus.
• The system does not create by product that will contaminate its surroundings.
• The system makes use of in situ resources such as high temperatures and high wind speeds. 

What do you hope to achieve?

We hope that Vnergy can power more space missions to Venus, to resolve the hidden mysteries in Venus. Our burning questions on how Venus came to be, how it has evolved, and how and why it is different from the atmospheres of Earth and Mars can finally be answered after ages of speculation. Vnergy will also pave the way for longer space exploration missions of the Milky Way in the future.

We also hope that Vnergy will spearhead more research in thermoelectric generation and create more efficient and cheaper energy solutions for mankind on Earth. Hence, more people will have equal access to cleaner energy.

What tools, coding languages, hardware, or software did you use to develop your project?

We used computer-aided design (CAD) software to model the thermal energy storage system. Using Solidworks, we were able to estimate the total mass and volume of the thermal energy storage system.

We utilised NASA’s Energy Storage Technologies for Future Planetary Science Missions article which inspired us to create a better energy solution for Venus. Our eyes were open to various energy solutions which were viable in high-temperature environments. Radioisotope Thermoelectric Generators (RTGs) from NASA's Cassini spacecraft served as the main inspiration for Vnergy and inspired us to create a thermoelectric generator for a high-temperature planet.

Not only that, we also used the Venus Resources by NASA. The Venus resources enlightened us on the hellish and unforgiving conditions on Venus. Data from the DAVINCI and VERITAS missions provided us with ideas to improve the design of the energy storage system.

We took inspiration from nanoengineered heat sink materials by the ames research centre from NASA. Hence, we decided to apply nanotechnology in our energy storage system in the form of nanocoatings and carbon nanotubes.

Previous NASA missions such as the Mars Exploration Rovers provided us with ideas to safely manoeuvre the energy storage system onto Venus. The aeroshell is used to minimise forces and vibrations due to launch, reentry, descent, and landing on Venus.

The experience was undoubtedly exciting, competitive, and intense. Our team managed to learn in depth about problem solving skills and challenges of sending spacecraft to foreign planetary bodies. Our eyes were opened to many novel technologies, and what it truly takes to be engineers. 

We were thoroughly impressed by the sheer conscientious effort it took by NASA engineers, in order to send just one probe to outer space. Hence, we hope to develop an effective and practical solution to solve energy scarcity when venturing out onto Venus, or potentially even other planetary bodies. 

As all of us were at different geographical locations with different time zones, we had to meet and discuss all our ideas virtually. We also had to get things done in a tight time frame, and faced setbacks due to our busy schedules. It really took a village to design the energy storage system and made us realise the strength of the team is each team member. The strength of each team member is the team.

https://www.nasa.gov/feature/automaton-rover-for-extreme-environments-aree/

https://solarsystem.nasa.gov/news/1519/venus-resources/?page=0&per_page=40&order=created_at+desc&search=&tags=Venus&category=324

https://www.nasa.gov/centers/ames/research/technology-onepagers/heat_sinks.html

https://mars.nasa.gov/mer/mission/spacecraft/entry-descent-and-landing-configuration/lander-structure

https://solarsystem.nasa.gov/missions/cassini/radioisotope-thermoelectric-generator/

https://mars.nasa.gov/internal_resources/788/

https://youtu.be/BvXa1n9fjow

https://www.researchgate.net/publication/309544851_Enhancement_of_Natural_Convection_by_Carbon_Nanotube_Films_Covered_Microchannel-Surface_for_Passive_Electronic_Cooling_Devices

https://www.sciencedirect.com/science/article/pii/S235248472101297X

https://www.sciencedirect.com/science/article/abs/pii/S0196890419311562

https://www.sciencedirect.com/science/article/pii/S235248472101297X#b10

#Venus #thermalenergy #thermalbattery #energy #storage