Few Words On Hydrogen

Hydrogen is getting a lot attention on the last decades and it is promoted as the cleanest energy source. I would like to share my opinions on the topic. All energy sources require mining and refining procedures before being used. Among these energy sources coal was used for decades with minimal processing after excavation. Later came the crude oil. It required refining to be utilized. Then came the natural gas which required comparably less energy intense refining process. Compared to all these fuels, hydrogen cannot be found on earth in pure format. At the moment hydrogen is obtained from methane gas. Therefore, hydrogen generation requires one more step after natural gas production.

Energy by all means pollute the environment. For my point of view, the energy source which can be obtained with fewer steps and has the highest energy density is the best energy source. This valuation is valid for pure substances. Unfortunately, purification process is very expensive especially for some material. Compared to coal and gasoline, natural gas is the purest with minimal hazardous impurities. Therefore, its use is promoted. However, many countries do not have natural gas reserves. Trying to substitute it with hydrogen does not make much sense while it also relies on methane for production. More importantly, liquid hydrogen is less energy dense than liquid natural gas in terms of volume and is very difficult to store in liquid form. I recommend countries to invest on methane production facilities. Facilities that generate methane from coal instead of generating hydrogen from methane which is exported.

Water vapor is a more dangerous greenhouse gas than carbon dioxide. Then what is the point of using hydrogen instead of natural gas and gasoline. Energy source which requires less environmental pollution during mining and refining and has the highest energy density is the GREENEST fuel. Methane is an ideal energy source. The excess energy generated by the renewable energy sources can be used to produce methane from coal which is widely available world-wide. The cars, planes and rockets can operate with methane. Later when nuclear energy becomes the dominant energy source, it can be used to produce methane that can be used safely by the vehicles.

The World Is Betting On The Wrong Horse.

Liquid Air Plane - Final

I have previously written about the liquid air powered plane. It had a major flaw in the pressure chamber. Liquid air needs to be heated to ambient temperature very fast. This cannot be achieved with heatsinks. Instead heat pumps need to be used. The evaporator section of the heat pump should be embedded inside the aluminum payload fairing. Then, the compressor would pump the ambient air’s heat to the pressure chamber. Heat pumps are 300 – 400 % efficient. Additionally, the energy lost on the compressor mainly turns into heat which is also utilized by the pressure chamber. The more heat that can be transferred to the pressure chamber, higher the efficiency of the liquid air engine would be.

The main turbine of the liquid air engine would be powered by the pressure of the expending air. When the engine is cold, main turbine would be heated by electric to start the engine. Once the main turbine is operational, it would run the heat pump which would generate the necessary heat for the engine. Main turbine would also run the liquid air pump and the electric generator.

Main engine would be a pressure chamber which would be fed by liquid air and internally heated by the heat pump’s condenser. The rapidly expending gas would generate pressure and would be exhausted by the rotatable engine nozzles. In this design, the wings would be stationary on the fuselage of the plane and only the engine nozzles would rotate. The plane would not be a VTOL but a short takeoff and landing plane.

Direct Nuclear to Electric Conversion

I had previously proposed direct heat to electric conversion using a novel Thermoelectronic Energy Conversion method. This method can be enhanced to operate on radioactive materials as well.

My proposition is to generate high energy electrons using gamma rays and then store them. Most widely used gamma ray emitter is Cobalt 60. It converts the energy of fast neutrons to gamma rays. These gamma rays can be used to remove and accelerate the outermost electrons of Rubidium. I chose Rubidium due to its low work function (energy required to strip an electron). It is also more abundant than Cesium which has slightly lower work function. Additionally, Rubidium is a better electric conductor than Cesium. Rubidium has a very low density and has a very large atomic radius which is not ideal to stop gamma rays. Therefore, a lead layer would be used to stop the gamma rays to propagate further. Ideally, most of the gamma rays should be used to excite electrons not to excite the nucleus of an atom.

The excited electrons would be further accelerated by the high potential on the plate of the setup. Like in a pentode vacuum tube. The electrons will be collected on the collector of the setup. The collected electrons would then be pumped into capacitors using special charge pump circuitry so that the circuit would be completed. In order to maintain a potential difference between the rubidium emitter and the aluminum collector, aluminum oxide layer will be used. The thickness of the layer would be such that it would allow electrons with certain potential difference.

Space Zen

Recently there was an event on small satellites. As the size of a satellite decreases, it is much easier to deploy more of them to the orbit however they also lose some abilities of the bigger counterparts. I see people complain about space debris and in the meanwhile promote tiny satellites.

Here is my opinion on the topic; space is not a playground and not everyone should send a satellite. As the satellites get smaller, they lose the ability to deorbit themselves at the end of their life. They also lose some of the redundancies of the bigger counterparts. As a result, if something fails, they immediately become a space junk. There should be minimum requirements for a satellite to decrease space debris.

People are trying to obtain more and more data from space. Do we really need that much data, if we cannot take action related with them? There should be a sweet spot for that.

At the heart of Zen-inspired minimalism lies the concept of simplicity. This design approach emphasizes the removal of excess, clutter, and unnecessary ornamentation. By paring down one’s surroundings to the essential elements, a sense of tranquility and clarity is cultivated.

Tranquility of space requires Zen approach. Every satellite and constellation deployed to space should be well thought about.

Feasibility of a Liquid Air Powered Autonomous Truck

I had previously proposed liquid air powered autonomous cargo trucks that operate on a dedicated suspended bridge highway. Recently, I made some calculations on the feasibility of a liquid air powered vehicle based on the theoretical values with acceptable correction factors. The results look promising. I would like to repeat again that the performance of liquid air cannot beat a combustion engine. However, it performs better than battery operated alternatives.

Theoretical energy density of liquid nitrogen at atmospheric pressure and 27 °C ambient temperature is about 213 W·h/kg, while typically only 97 W·h/kg can be achieved under realistic circumstances. This compares with 100–250 W·h/kg for a lithium-ion battery and 3,000 W·h/kg for a gasoline combustion engine running at 28% thermal efficiency (Liquid nitrogen engine). Most notable advantage of liquid air is its Carnot efficiency. At 27 °C ambient temperature it is 74.3 %; at -16 °C ambient temperature it is 70 %. At such low temperatures, batteries have no chance and even diesel engines struggle to operate due to freezing of diesel.

I made my calculations for a full-sized container carrying truck. The weight of the truck with full fuel tank was 7300 kg (600kg fuel), the trailer was 6000 kg, the payload was 16,000 kg. I set the energy density of liquid air to be 1 / 20 of a diesel engine. In order to achieve half the range of a diesel truck it would require 6000 kg of liquid air. However, autonomous trucks have advantages in terms of weight because they can simply be a motorized trailer. Additionally, the cryogenic tanks can be designed to be used as the chassis. As a result, the liquid air powered autonomous container carrier can accommodate such a huge fuel tank with the same weight as a traditional truck with a trailer for half the range. One more advantage of such a huge fuel tank is, as it is depleted the truck gets much lighter compared to a diesel truck and its fuel consumption gets lower.

The prerequisites for this idea are light weight composite fuel tanks, light weight and high thermal conductive heat exchangers to create pressure that would turn the wheels. Aluminum alloy heat exchangers with carbon fiber can be a solution for that.

Ply Aluminum Storage

Wind energy is unpredictable and therefore require additional systems to meet the demand. Batteries are expensive and more importantly cannot handle so many charge recharge cycle. On the other hand, capacitors have much longer endurance. I would like to propose a simple capacitor design that can be used to store the excess energy of a wind turbine. It is just ply of aluminum and aluminum oxide. It is comparably easy to grow a thin layer of oxide over aluminum or remove the excess of it. They also form a very solid structure; higher strength compared to aluminum itself like the plywood.

Wind turbines require strong tower structures as a support. Ply aluminum capacitor can also meet this demand. A dual-purpose ply aluminum tower structure which doubles as a giant capacitor. Unlike batteries, this giant capacitor can be built to store high voltages. Therefore, it would be easy to charge them compared to complex balanced cell charging of batteries.

This technology can also be utilized on the construction of the buildings to compensate for the demand inequalities and to correct the power factor.

VTOL

I had previously proposed a VTOL design using liquid air. The same design can be implemented using rocket engines. Liquid propellant would generate more thrust and range compared to liquid air counterpart. At the moment there is no proper VTOL plane. Propeller powered ones lift off like a helicopter. Which has low lift capacity and very dependent on the elevation. Turbofan engines on the other hand are two heavy and thrust vectoring using nozzles produce inadequate takeoff thrust. When it comes to vertical takeoff nothing comes close to the rocket engines. They can takeoff at any altitude unlike helicopters and produce much more thrust than a turbofan. They are also much lighter compared to the thrust they produce.

My proposed plane will have four rocket engines on their sides and several (depends on the thrust requirement) engines on its bottom. Each side engine will be sandwiched between two wings for proper support and increased lift area. The wings and the nozzle of the rocket engine will be rotatable. This will allow all the engines to generate vertical thrust and vertically oriented wings to produce minimum drag while takeoff. The wings will be thin and flat with no curvature. The lift will be generated by the angle of attack of the wings. This slight orientation of the wings and the engine nozzles will generate lift. Multiple wings allow more even distribution of the load and reduce the stall speed of the plane. Additionally, the engines will have cascaded nozzles that I had proposed earlier. Together with low stall speed, the fuel consumption of the plane will be lowered.

The wings and the engine nozzle will be rotated by the directed exhaust gas of the engine. Therefore, there will be no need for high power heavy actuators for rotation. The payload fairing on top of the plane can accommodate military missiles as well as rockets for space. The rocket engines of the plane allow it to reach very high altitudes compared to traditional planes. This is beneficial for military defense while not many missiles can reach the plane. This is also beneficial for the space rockets while the rocket will not need to go through the dense atmosphere.