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Kirpichnikova I.M., Doctor of Technical Sciences, Professor

Vozmilova A.A., Postgraduate student

South Ural State University, Chelyabinsk, Russia

THE SYSTEM OF THE HEATING BUILDINGS FOR THE CONTINENTAL CLIMATE

Modern tendencies of power complex development imply availability of effective solutions concerning contraction of energy consumption levels. Here belongs the usage of energy-efficient technologies on the basis of renewable energy sources. One of such solutions can be represented in the form of conjugation of wind-energy set of vertical-axis type “Wind turbine-3” with the wattage of 3 kW produced by State Rocket Centre “SRC-Vertical” Ltd. in Miass city, Chelyabinsk region, and infrared membranous electric heater.

Wind-energy set is a technical device aimed at conversion of wind power into electric power. The key elements are wind turbine rotor with impellers, generator component, aerodynamic brake, hub group and lattice girder (Fig.1).

Lattice girder

Hub group

Aerodynamic brake

Generator component

Rotor with impellers

Figure 1. Vertical-axis turbine device

Rotational speed reaches a certain number of turns per minute, with a further strengthening of the wind, is stabilized by the so-called aerodynamic brakes, invented by "SRC-Vertical" scientists. To work in cold conditions, such as in the Far North, the blades are equipped with special coal-plastic slick, that prevents surface icing of blades. The hub contains a specially designed bearing system that allows the maximum to reduce the losses from the moment of resistance.
In the continental climate of Russia, on 16-20 meters mast, the average wind speed is 5-6 m / sec. Given the optimal location of wind turbine (mountains, coastal areas of seas and lakes, tundra, etc.), the speed can be up to 6.5 m / sec. Wind turbine-3 at a speed of 6.5 m / s produces 1 kW of instantaneous power [1]. This power can be used to energize the slick heater.

Membranous electric heater is aimed at economical, highly comfortable and effective heating-up of accommodations, office buildings and industrial enterprises. Heater is a multilayered polymeric material inside of which a resistive heating unit and an aluminum shield are integrated. The shield functions as a radiator for temperature equalizing on the whole surface of the heater and as a radiating element. Heater is only an element constituent of building up an infrared system of central heating and separate usage of it and of other elements (heating controllers and heat-reflecting thermal insulator) is not rational.

The system operation is as follows. When power is applied to the resistive element, the latter is heated to 40-50 C°. The aluminum screen allows to distribute heat evenly across the surface of heater. Ceiling surface areas in this case must be closed with heater elements on 65%. Further distribution of heat is due to radiant heat exchange (infrared radiation).

Inside the room the slick is mounted on the ceiling surface and can be closed almost with any kind of building decoration. Room temperature is controlled by the thermo regulator manually, automatically or remotely and requires no special maintenance. If necessary, a slick heater can be installed in walls and under carpeting.

Heater is plugged-into a three-phase wind turbine generator with the help of the primitive regulator which allows to stabilize the constant voltage equalizing 48 V on account of bridging connection of four series-connected electric accumulators with the voltage equalizing of 12 V. Wind turbine generator voltage due to its variability as to electrical angle, electric frequency and amplitude changes from 0 to 300 V. Constant voltage at the voltage regulator output is 48 V. (Fig. 2).

This scheme allows to provide continual heating-up of buildings according to construction norms and regulations. It allows to predict the efficiency of the usage of such a system in wide application and mass consumption as well. Moreover, it is important to choose parameters of the wind turbine and heater to match according to their characteristics.

On-peak loads and operation conditions of the system are characterized by a considerable power demand – 200 W. per maveragely. Such wattage cannot be provided by accumulator battery (wind turbine), but it can be obtained through triggering mode. In its normal mode wind turbine compensated the energy consumed. Besides, it is possible to heat-up several rooms simultaneously or to diminish the line load during the activation when using a controller allowing to gradually heat-up the building on account of successive warming-up.

Figure 2. Heater connection scheme

Thus, the system can be divided into two parts:

1) wind turbine-3 - battery;

2) battery - heater;

The presence of a battery in the system is very important. In addition to energy reserve battery will cover the peak power consumption during system startup.

Wind Turbine works on accumulator battery. This section of the load energizing chain is realized with a fairly high degree of difficulty based on the intellectual controller. Based on the external parameters (battery charging current, load current, the instantaneous available power), the controller should ensure optimal operation of the system to be able to provide comfortable living conditions.

Naturally, the better the room will be thermally insulated, the smaller will be the magnitude of conductive heat loss and, consequently, the minimum energy consumption, as in the mode of start-up and working. Therefore, the maximum degree of insulation – the one of the important factors of high working efficiency of the "Wind turbine-heater" system.

Directly load (heater) powered by 48 DCV. Heater heated to a temperature +45 ⁰C. On the surfaces whose temperature is different from + 45 ⁰C, there is radiant heat exchange. In turn, the intensity of this heat exchange will depend on the characteristics and geometry of the surfaces themselves, and, specifically, the degree of blackness (ε) and coefficient of irradiance (φ_1-2). The higher the value ε (not to exceed 1) in the infrared spectrum, the more heat can get the surface involved in the radiant heat exchange. Coefficient φ_1-2 shows the proportion of the radiant flow incident on the heated surface of the total flow radiated by the heating elements. This parameter is for all cases of possible arrangement of surfaces in the room can be determined from the graphical dependences, which makes it clear that with increasing height space of the room proportion of the heat flow falling on the floor, decreases, and against to the walls increases.

Heating the room with the help of heaters does not allow drafts. In addition, the walling must have the highest heat resistance. For this reason, for example, do not use a system of "Wind turbine-heater" for room heating with walling based on foam plastic ("fabricated" homes).

Using conventional thermo regulator can lead to an overestimation of the level of energy consumption, as they have an infelicity of regulation ±2 ^îC. An increase of the setting temperature on 1 ^îC leads to an overestimation of energy consumption by 5%. It is therefore advisable to use digital temperature sensors with microcontroller control systems. In this case, the infelicity of regulation is ±0,1^îC. Also useful to divide at least two modes of heating. For example:

1) Power Save Mode (12-14 ^îC). The lower bound must not be below the dew point. Such a mode will not unfreeze the room and significantly reduce energy consumption during the absence of people.

2) Comfort mode (19-21 ^îC). Due to the high growth over a short period of time creates conditions favorable for human habitation.

Switching between modes can be done remotely through GSM - modules, which increases the attractiveness of such a system for remote areas. In addition, it is known that at the infrared heating comfort is achieved at lower air temperatures (17-18 ^îC) than at convective heating method. Also infrared heat dries out the insulation materials, reduces their coefficient of thermal conductivity, and consequently, lower heat loss than at convective heat exchange. Running the system at low negative ambient temperatures determines the largest by value (200 W/m².) and the duration of peak energy consumption, which is extremely undesirable. The system should be run at the first stable cooling (late summer - early fall).

The lack of installed capacity (heating several rooms) is one of the main problems. Provides several solutions:

- The use of non-priority load disconnection relay (some rooms are heated by the residual principle);

- The alternate inclusion of rooms on equal intervals;

- The use of 2 or more wind turbines;

- Use of more powerful wind turbine;

- Conjugation of the "Wind turbine-heater" system with other energy sources (solar battery, diesel - generator, electrical grids);

- The use of the "Wind turbine-heater" system as an additional heating;

- Use a larger capacity battery;

- Reducing heat losses as well as electrical losses at the energy transformation.

This heating system can be applied to heat-up those accommodations, which are situated considerably far from central heating systems, electric power supply and gas-supply (country houses, farms, tourist centers, fishing and hunting husbandries, caravans in temporary villages, exploration crews, frontier posts and other similar objects). (Fig. 3).

Figure 3. Energizing of infrared slick heater by wind turbine-3

It is efficient to use this system in cases when expenditures on traditional central heating-up systems exceed expenditures on the solution of this problem using wind turbine-heater. This system will be used effectively in a continental climate, for example, on the North of Russia and Scandinavian countries such as Finland, Sweden, etc.

List of references

1. Kirpichnikova, I.M., Solomin E.V. Vertical axis Wind Turbine / / Journal of South Ural State University “Vestnik”. "Energy" series.- 2008. - Ed. 10, ¹ 26. - P.15-16.

2. Kirpichnikova, I.M., Solomin E.V. Panasyuk I.N. Conjugation of low power wind turbine with the slick electric heater for room heating / / Journal of South Ural State University “Vestnik”. "Energy" series. - 2009. - Ed. 12, ¹ 34. - P.74-77.