Extracts from
The Third International Conference
on New Energy Systems and Conversions
in Kazan (Russia) - 1997

Kazan State Technical University named after A.N.Tupolev

CCR NOCO REACTOR POWERED WITH THERMOELECTRIC GENERATOR
FOR HYDROGEN OR ELECTRICITY PRODUCTION

ABSTRACT. The preliminary estimation of the possibilities and of the main characteristics of electricity production by Thermoelectric Power Generator ( TPG), based on Ecology Clean Combustion Chamber - CCR NOCO Reactor with heat capacity 30 kW - 2 MW 'is done. Different cases of using TPG with CCR NOCO-reactor are examined. It's shown, that efficiency of TPG, based on available low - & middle - temperature semiconductor materials can be as high as 7-14% . The practical application of high temperature materials which could help to obtain an efficiency of about 20% needs more detailed scientific study.

KEY WORDS:
CCR NOCO-reactor, boiler, waste fuels, electricity , cogeneration, thermoelectricity, semiconductor materials.

CCR NOCO Reactor is a well-known combustion device, able to burn gaseous, liquid or solid fuel and waste (such as rubber tires, waste oil...), without any visible injurious pollution.

Combined with a good common technology for boilers, stoves and incinerators, the CCR NOCO Reactor technology consists in the:

• AN ALWAYS COMPLETE COMBUSTION of hydrocarbons and VOC carcinogenic hydrocarbons (such as CO, formaldehydes, benzpyrenes and dioxins).
  
• CONDENSATION of the exhaust gas by removing the sulfur, chlorine, etc... and separating all micro-particles using the calcium filter. These byproducts react with the calcium to produce gypsum.
  
• RECYCLING by channeling the clean exhaust gas with its CO₂ into lake/water systems. Bubbling through excess CO₂ will create a fertile area capable of growing rice, or algae (producing proteins). Increased vegetation will also increase oxygen production.

The burning temperature in CCR NOCO Reactor is quite high and that of its ceramic shell reaches 1000-1100°C. Thus, CCR NOCO Reactor is a good emitter of intensive infrared radiation (IR). The radiation heat flow rate is close to 80% of the total heat production of combustion chamber and only 20 % goes out with the flue - gases.

The high density of IR result from the small dimensions of apparatus, assembled with CCR NOCO-reactor. However, since it is absorbed on the wall of the boiler, the high temperature IR becomes heat upon quite low temperature.

According to the Second Law of Thermodynamics Analyses, the temperature drop between the boiler and the reactor must be regarded as a loss of the temperature potential. This loss can be reduced by transforming the heat into another kind of energy, electricity in particular.

When a boiler with CCR NOCO Reactor is powered with a device for electricity production, it becomes a power plant for combined production of heat and power. In such case, the efficiency of the transformation of heat into electricity only determines the value of the electricity as part of the total energy output, but it does not influence the value of specific fuel expenditure for getting electricity. In other words, it allows getting relatively cheap electricity even with a rather low efficiency of heat conversion into power, especially when CCR NOCO Reactor burns waste fuel.

The direct conversion of heat by means of thermoelectricity phenomena is not the only and the most effective way to do it. But this technology seems to be the simplest and the most suitable for CCR NOCO-reactor among all the available ones.

Among the advantages of the thermoelectric transformers, are the absence of any mechanical motion, noise and high-pressure equipment, high reliability, no need of service, in addition to the ecological cleanliness.

The figure below shows how a TPG unit can be included into a CCR NOCO Reactor boiler for domestic water heating (total heat capacity is about 2 MW).

Diameter of reactor m 0.9 Lenght of reactor m 3.5 Temperature of the reactor shell °C 1100 Total heat capacity MW 2.0 Heat capacity of boiler MW 1.6

FIG. 1

In the calculations, TPG is supposed to consist of one or two different cascades, each of which being formed by a number of semiconductor thermopiles that are joined together electrically. Connection is determined by electrical parameters of useful needed load. On its hot junction, each thermopile of the first (upper) cascade has a receiver plate which absorbs the IR of the CCR NOCO Reactor. Cold thermojunctions of thermopiles in the second (lower) cascade are assembled on the inner wall of the boiler.

Efficiency of TPG is firstly determined by the properties of thermoelectrical materials that are used. At the same time, the right choice of the materials depends on thermal regime of working of the cascades. It is determined by conditions of optimal accordance of TPG with IR emitter.

In the case of CCR NOCO-reactors, these materials are found by taking into consideration the thermal interaction between the reactor and the receiver plates of thermopiles. The higher the receiver plate's temperature, the bigger the electrical output of TPG, but so is its thermal resistance. Therefore, if the temperature of the CCR NOCO Reactor is constant, its heat power falls as the electrical output of TPG increases. This is the reason why there is an optimal temperature of thermopile receivers at which the electrical output of TPG reaches its maximum value. According to our calculation, the optimal temperature of the receiver is around 800 K to 900 K. This region assumes the optimal application of middle- and low - temperature materials in one or two cascades.

The results of more detailed calculations of TPG, which were held for CCR NOCO Reactor with the heat capacity of 2 MW (the IR capacity - 1.6 MW) in accordance with the traditional method of " average properties" [1], are presented in the table below. The calculations were held by taking into account the properties of easy available materials, such as low temperature triple alloys of Bi, Sb and Te, and middle temperature alloys of Pb and Te. The thermal leakage and contact electrical losses of TPG were determined as shown in [2,3]. According to the presented results, and using the single cascade low temperature, TPG (in 2 MW boiler) permits to obtain 115 kW of electricity production and does not visibly influence the CCR NOCO Reactor's work. The use of the double cascade increases the electrical output up to 196 kW, but makes the heat capacity of the reactor fall down to 12.5%. Therefore, any increase of working temperature to get more electricity must be accompanied by special measures directed to the intensification of heat transfer between the reactor and the TPG.

If the measures are successful, the efficiency of the TPG will go up to 20 %.

References
1. Thermoelements and thermoelectric devices. Reference book. L. Anatichuk . Kiev, Naukova dumka ,1979- 768 p.
2. Calculation and design of thermoelectrical generators and heat pumps. G. Kotirlo, G. Lobunech. Kiev, Naukova dumka, 1980 - 327 p.
3. B. Pozdniakov, E. Koptelov. Thermoelectric energetics. Moskow, Atom izdat, 1979.

URL: http://www.rcwo.com/noco/conf/