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Technical stuff


This page contains more technical details, calculations and explanations.

Gas turbine used in example



Picture Kawasaki 80DLEThe technical specifications of the Kawasaki GPC 80 DLE gas turbine model are used for the example on the Welcome page in order to give an impression on how much energy could be saved if heating elements are used to heat the air.

According to the Kawasaki site the fuel consumption of this model is 23492 kJ/s. This is the equivalent 23492 kWh or 2664 m³ of natural gas.

The air in the 8 combustors is heated to 1200 C. It can generate 7800 kW of electricity.
 



Electric heating elements


The electric heating element in each one of the 8 combustors in fig. 2 on the Welcome page is based on the Kanthal Super element.

The combustors of the electric gas turbine and the heating elements may have to be redesigned for optimal efficiency.

This will allow the combustors to take in the same volume of air as the conventional combustors and heat the air to the same temperature as the combustors in the conventional gas turbine.

If possible, the interior of the combustors is made reflective. This way much of the heat radiated by the heating element is reflected by the sides of the combustor - fig. 1a on the Welcome page. This way the air can be more evenly heated and this will also save energy.

These elements heat the air coming from the compressors to 1200 C. This should possible because these type elements themselves can heat up to 1500 C. Each electric heating element consumes 7 kW (length 1250 mm). Their combined energy consumption is 56 kW. If you would like to know more, you can download / read a case story from Kanthal by clicking here.

Project Pluto


Launching of the Pluto nuclear scramjet
Project Pluto was a United States government program to develop nuclear powered ramjet engines for use in cruise missiles.

Despite successful tests it never flew. The weapon was considered "too provocative".

You can learn more about the Pluto Project by visiting these links: Project Pluto - Wikipedia,
Vought Aircraft Heritage site - Pluto, The Flying Crowbar, Directory of US military rockets and missiles - Vought SLAM (Pluto)




Nuclear reactor of the Pluto scramjet
Technical details of the nuclear reactor:

Diameter----------------------57.25 inch
Fissionable Core-------------47.24 inch
Length-------------------------64.24 inch
Core Length------------------50.70 inch
Critical Mass of Uranium--59.90 kg.
Avg. Power Density---------10 MW/cubic foot
Total Power-------------------600 MW
Avg. Element Temperature- 2,330 F
>> Online conversion tools



Power supply for the electric gas turbine


1000 kw diesel generator consumes 269 litersThe power is supplied by a 1000 kW diesel generator. According to this site the average diesel generator has an approximate fuel consumption of ± 269 l/hour (full load). Consequently, the electric gas turbine consumes 269 liters of diesel per hour. This equals 2690 kWh.

To be on the safe side, the total energy consumption of the electric gas turbine is set at 1000 kW, allowing 944 kW for peripheral equipment e.g. control panel, starter engine etc.

Equal heat, air pressure, volume and speed = equal electric efficiency


The electric gas turbine is as efficient as the conventional gas turbine because:

> It can take in the same volume of air as the fig. 2 gas turbine
> It can compress the air to same level as the fig. 2 gas turbine
> It can heat the air to the same temperature as the fig. 2 gas turbine

Meaning: the air stream produced by the electric gas turbine wil have the same volume, speed, pressure and temperature as the air stream produced by the conventional gas turbine.

Consequently, the electric gas turbine has the same power as the conventional gas turbine and can drive the same type of generator, generating the same electric output

Saves CO2, fuel and money


Picture of fist full of dollarsWhen you compare the energy consumption of the conventional gas turbine to that of the diesel generator that powers the electric gas turbine, you can easily see which gas turbine is the most efficient one!

The 20828 kWh that can be saved, is the energy equivalent of 2362 m³ of natural gas per hour. The European price level for natural gas was in 2008 $500 per 1000 cubic meters. So one would save over $1000 per hour.

Fig. 2 - gas turbine on natural gas consumes                         
Fig. 3 - diesel generator powering heating elements consumes   
Amount of energy saved                                                      
23492 kWh
2664 kWh
20828 kWh

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Save even more


It is also possible to start the electric gas turbine by using electricity stored in batteries or flywheels that was previously generated by wind turbines and/or solar panels.

Once the electric gas turbine is up and running, the 1000 kW that is needed to power it can be tapped from the generator's 7800 kW output. This can be done either directly or via the power grid.

This implies the electric gas turbine can generate 7 times the amount of energy it consumes.

Violating The Laws of Thermodynamics


Picture of Albert Einstein sticking out his tongue The "Save even more" section suggests that the electric gas turbine is a perpetuum mobile or free-energy device. (Visit Patrick J. Kelly's Practical Guide to Free-Energy Devices for a very complete over view).

It is not. You just get a lot more out of a litre of fossil or bio fuel.

The diesel generator consumes 2690 kWh but generates only 1000 kW. This means 1690 kWh is lost in the process of generating electricity. This is in full compliance with the laws of thermodynamics. Also the heating elements last about 1500 hours, sot they need to be replaced once every 5 weeks. This also can be considered as a form of energy loss.

Summary


Obviously it is far more efficient to heat air using electric heating elements than by burning fossil or bio fuels because:
1.
Kanthal Super elements can heat air to 1200 C in a semi open space like a combustor, especially so if the inside of the combustor can be made to reflect the heat radiated by the heating elements.
2.
1000 kW are enough to power 8 Kanthal Super elements of 7 kW each.
3. 
The average 1000 kW diesel generator consumes 269 liters of diesel.
4.
In order to drive a turbine it is not necessary to burn fuel to heat air. Nuclear gas turbines or pebble bed reactors use nuclear fuel to heat helium, or in case of the Adams Engine, nitrogen!

Final remarks


If the electric gas turbine can heat the same volume of air to the same temperature as the conventional gas turbine, it should also be able produce an air flow with the same temperature, volume, pressure and speed as the conventional gas turbine.

Therefore, the electric gas turbine should be capable of driving the same type of generator as the conventional gas turbine, and be able to generate the same amount of electricity.

Picture of ceramics oven or kilnBut even if each combustor of the electric gas turbine consumes 450 kW like the furnace on the left, it would still be very efficient. And 450 kW is lot of energy.

The picture on the left shows the interior of a ceramics kiln (furnace). Its 48 heating elements heat 10 m3 of porcelain.

Each element is rated just under 10 kW or 10000 watts. That might not seem much but the gas flame you might use for cooking is about 300 watts. So one 10 kW heating element equals about 33 gas flames.

Imagine that kind of heat radiated inside a electric gas turbine combustor with a volume of 1 m3. That is a cylinder with a diameter of 100 centimetres and a height of 150 centimetres.