RU2608448C1 - Micro-cogeneration unit operating on renewable energy sources - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to thermal electric power industry. Micro-cogeneration unit represents a single module assembled on the basis of an energy-intensive high-temperature heat accumulator with a hybrid system of heating from renewable energy sources (RES), mainly sun and wind ones. Steam boiler has a design providing automatic maintaining the steam pressure within a specified mode without any automation means, and the steam turbine maintains stable rpm within a rated interval of loads on the electric generator. Return of the condensate into the boiler is provided without pumps and without loss of the working medium. Heat exchanger of the turbine unit transmits "waste" heat for heating rooms and for the main routine needs.

EFFECT: micro-cogeneration unit operating on renewable energy sources provides independent power supply of such objects as individual housing, small agricultural productions, crafts, remote health or environmental and tourism assets.

1 cl, 3 dwg

Description

The invention relates to the field of power engineering and can be used in autonomous integrated energy supply systems for small objects, mainly from renewable energy sources.

Micro-TPPs, currently, according to the Internet, already have thousands of users. Various technical solutions are implemented in the manufactured and designed designs - from the traditional internal combustion engine (Otto engine), to steam turbines and reciprocating engines, as well as the Stirling engine. When mastering the production of this equipment, manufacturers provide arguments of both economic and environmental nature: the high (more than 90%) combined efficiency of the micro-CHP provides a reduction in energy costs and the amount of harmful emissions, in particular carbon dioxide into the atmosphere.

So, for example, Senertec GmbH, part of the Baxi Group, has currently sold about 150,000 Dachs combustion engines. Electric power - from 5 kW, thermal - from 12.5 to 20.5. Various models of Dachs units operate on natural, liquefied gas, diesel fuel. There is a Dachs RS model designed to run on rapeseed oil biodiesel. Micro-CHP (Mini-BHKW) Ecopover of the German company PoverPlus Technologies is already on the European market. Its electric power varies in the range from 1.3 to 4.7, thermal - from 4.0 to 12.5 kW. The total efficiency of the installation exceeds 90%, the fuel for it is natural or liquefied gas.

Otag Vertribes has released a pilot batch of Lion-Powerblock floor gas micro-CHP with an electric power of 0.2-2.2, thermal - 2.5-16.0 kW. It uses a steam two-cylinder engine with a twin free-moving piston. The steam generator of the apparatus consists of a pressurized burner and a steel coil; steam temperature 350 ° C.

MTT Micro Turbine Technology BV (Netherlands) has created an EnerTwin installation based on a microturbine that simultaneously generates 3 kW of electricity and 15 kW of heat.

Despite the originality of the designs of the listed micro-thermal power plants, they cannot be used in autonomous energy supply systems from renewable energy sources (RES), since they operate on traditional fuel.

A combined heat and power plant based on a Stirling engine is known, including an engine (for example, a Stirling engine or an internal combustion engine) and an electric generator located on the same shaft, their cooling system, consisting of a closed loop with a heat exchanger-cooler through which an external heat supply system passes , it is equipped with a steam production line, consisting of a steam generator, a superheater, with a check valve between them, and an engine cooling circuit connected to the steam generator rum jumper with control and non-return valves, including a steam-water pump-heater, a start-up bypass line with a pump and shut-off valves, while the steam production line is connected to the engine cooling system through the steam-water pump-heater, and the exhaust gas line first passes through the superheater, and then through the steam generator (RF patent No. 2164613 C1, F02G 1/043, F25B 9/14).

A self-contained cogeneration power plant is known, which includes a direct cycle converter (for example, an internal combustion engine or a Stirling engine) with an electric generator on one shaft, a fuel supply line, an engine exhaust heat exchanger-heat exchanger through which the engine exhaust line passes, and an external heat supply system with heat consumers, characterized in that it is equipped with a single closed loop heat transfer from the engine to heat consumers, consisting of a hearth chi of hot water to external consumers of heat passing through the engine cooling jacket, an engine exhaust heat exchanger-heat exchanger, a single circulation pump, and chilled water return lines coming from heat consumers to the engine cooling jacket, while the chilled water return line is connected to the heat exchanger -the utilizer with a jumper with a control valve, and after the jumper in front of the engine, a second control valve is installed on the return line (RF patent No. 2162534, F02G 5/02, F02G 1/043, F02B 65/00).

The last two plants of domestic design also run on traditional fuels, in addition, they have a rather complicated design, which requires qualified service and therefore creates certain problems for ordinary users.

From all known power plants using renewable energy resources, it is possible to single out the SOLAR MODULAR POWER INSTALLATION according to the patent of the Russian Federation No. 2032082, cl. F01K 13/00, 1995, which can be taken as a prototype. Here it is appropriate to cite its claims:

“A solar modular power plant, including a steam generator with an economizer, evaporator and superheater heat exchange surfaces, a turbine with a generator and a condenser, as well as a feed water supply system with a low pressure regenerative heater, a metering device and a feed pump, in series the economizer and evaporative heat transfer surfaces are made in the form of parabolocilinar modular concentrators, and aro-superheater - with a fuel supply, characterized in that, in order to increase efficiency and ensure autonomous start-up, it is additionally equipped with a separator tank and a feed water heater, the latter being made in the form of parabolic cylindrical modular concentrators with photoelectric converters placed in them and connected to the feed system feed water parallel to the low-pressure heater, and a separator tank is placed between the evaporative and superheater surfaces of the heat exchanger and connected to the entrance to the exit of the evaporator heat transfer surface, a pair of output - to the superheater heat exchange surface, and the yield of the water - to a feed water system for deaerator ".

Already from the Formula itself, the complexity of this system with solar concentrators for generating steam and the operation of photovoltaic converters, heat exchangers is clear, and the backup fuel supply system is also mentioned in the Description. And finally, the illustration to it shows a complete diagram of a device with many complex components. All this casts doubt on the prospects of the practical implementation of such an installation, and the lack of information even about its prototypes for 20 years since the publication of the invention only confirms this.

The task of developing the micro-CHPP of the proposed design is to create a simple cogeneration unit using renewable energy sources and working from its storage devices - heat accumulators, which ensure stable integrated power supply of small objects of various purposes.

This problem is solved in that, taking into account the properties of the simplest in design and practically maintenance-free pebble heat accumulators, to keep the temperature up to 200 and more degrees, a compact steam turbine with self-regulation of steam pressure and speed in a wide load range, with built-in heat exchanger and a “pumpless” condensate return device to the evaporation chamber. At the same time, the most effective methods of heating from renewable energy sources of heat-accumulating materials to the required temperature were used. All this removes the need for traditional fuel, extremely simplifies the design of the installation, eliminates the need for its maintenance by qualified personnel, increases the reliability of energy supply and saves money on capital and operating costs.

The description of the claimed micro-CHP is illustrated by illustrations, where in FIG. 1 shows an embodiment of an integrated installation for autonomous power supply; FIG. 2 is a sectional view of a steam power block of a micro-CHP; in FIG. 3 shows a condensate return device (section AA of this block, FIG. 2).

The inventive micro-CHP is a single module, all of the structural elements of which can be manufactured in the factory, which will allow to master their mass production and facilitate installation at the place of installation. In such an embodiment, it is shown in FIG. 1. The case of the heat accumulator 1 is at the same time the base of both the wind thermal installation (VTU) 2 and the solar collector-heater (SKN) 3. Inside the heat accumulator, in the space with the maximum temperature for heating the air, the primary transducers contain a micro-CHP steam generator 4 consisting of a boiler body 5 (see Fig. 2) with a finned surface, a conical or spherical bottom 6, a buffer tank 7, a superheater 8 in the form of a coaxial chamber between the wall of the housing and the inner heat-insulated cylinder 9, equipped with an annular bypass valve 10 (for example, of organosilicon polymer). The boiler 5 is equipped with an external heat-insulated shell 11 with a number of inlets in its upper part and a fan 12 at the bottom. A turbine unit 13 is located above the steam generator 4 (outside the heat accumulator 1). The steam turbine 14 is equipped with a transmitted torque sensor 15 (with a structure, for example, similar to the known axial spring-cam clutch), kinematically connected to the spool device 16 in the form of a rotary ring with holes and nozzle elements coaxial with them 17. The bottom of the turbine compartment also has a conical shape with an annular recess in the central part where the “pump-less” return device is located condensate, similar in structure to a known volume dispenser. It consists of a ring 18 with through cavities located around the circumference and end walls tightly adjacent to it with openings displaced in a circle — upper relative to lower — (see Fig. 3). This ring is connected to the turbine 14 by a reduction gear (see FIG. 2).

A fan (pump) 19 of the heat exchange circuit with a heat exchanger - an annular chamber around the wall of the turbine unit 13 (see Fig. 2) can be connected to the turbine shaft. To improve heat transfer, this wall may have an external fin, for example, in the form of a spiral inside the annular chamber of the heat exchanger, as shown in FIG. 2.

An electric generator 20 is also connected to the shaft, for example, by belt transmission. If necessary, a more rigorous stabilization of the generator shaft speed can be used instead of belt transmission, one of the known variators with automatic transmission ratio control can be used.

Preferred options for VTU 2 as part of the inventive micro-CHPP are known wind turbines with a vertical shaft on which an axial fan can be installed inside the heat accumulator, as shown in FIG. one.

SKN 3 panels located on the walls of the heat accumulator illuminated by the sun are made of sheet metal with a light-absorbing external surface. It has a selective coating and a transparent insulating fence. The panels can be equipped with reflective visors 21 located above them with a mirrored lower surface, which, moreover, is the protection of the panels from atmospheric precipitation. The angle of the visors should provide maximum additional solar exposure of the panels in the winter.

The remaining surface of the heat accumulator, the heat exchanger casing on the turbine unit body 13, as well as the pipelines of the heat exchange circuit are thermally insulated, for example, with the known organosilicate compounds Siltek, Bronya, Corundum, etc.

For normal operation of the micro-CHP, it is necessary to have an air temperature of at least 180 ° C in the upper part of the internal space of the heat accumulator 1. This temperature is created by the wind-thermal installation 2 and the solar collector-heater 3. When using environmentally friendly breathable heat-accumulating material, the maximum temperature of its heating is limited only by the balance between the stored heat, as well as from the primary energy converters, and its consumption, taking into account all heat losses. In this case, heating of the heat-accumulating material throughout its entire volume is carried out by forced air circulation from VTU 2nd natural - from SKN 3. Forced circulation heats the material, as in the well-known aerodynamic drying chamber, only the heating temperature can far exceed the moisture required for evaporation, which is absent in the heat accumulator 1. And solar panels with their minimal external heat losses will only intensify this heating during solar irradiation. In the presence of reflective visors 21, this effect increases.

Such a “hybrid” heating system that uses more than one energy source can reduce interruptions in replenishing the battery’s thermal resource and reduce its size while maintaining the calculated reliability of energy supply.

The micro-CHP is put into operation by turning on fan 12. A stream of hot air heats the walls and bottom 6 of boiler 5 to boiling water - in its strictly defined volume, covering only the bottom surface. The increased pressure of the formed vapor, part of the fluid moves into the buffer tank 7, compressing the air in it to the same pressure. At the same time, the water level outside it decreases and the changing heat transfer area from the bottom 6 automatically maintains this balance. Upon reaching the minimum working pressure of the steam, it, overcoming the crimping force of the annular valve 10, passes through the holes of the inner cylinder 9 into the superheater 8 and, with the speed increased due to its overheating, enters the nozzle elements 17 located in a circle. In this case, the turbine is not loaded 14 is rapidly gaining estimated speed. With the appearance of an increasing load on it, its sleeve squeezes the crown of the sensor 15, which, through symmetrically arranged lever mechanisms, rotates the ring of the spool device 16, increasing the steam supply to the nozzle elements 17. Thus, the speed of the turbine shaft is maintained within specified limits.

With the optimal ratio of the speed at the exit of the nozzle elements 17 of the steam flow and the peripheral speed of the turbine blades 14, it transfers to it its kinetic energy and at a minimum speed falls on the wall cooled by the heat exchanger, turning into condensate (see the leader in Fig. 2), which drains along it and further along the conical surface of the bottom of the housing of the turbine unit 13 to the condensate return device. Here, through the holes, it fills the cavities of the low-speed rotating ring 18, tightly closed at that moment by the bottom wall, and at the next moment, when the ring is rotated at some angle and the condensate-filled cavities are tightly closed from above, they pass over the lower holes and the condensate flows the boiler 5 along the wall of the tank 7, cooling it and preventing the liquid from boiling in it, thereby maintaining the operating air pressure there. It should be added that the extremely short circuit of the circulation of the working fluid in a confined space of the boiler 5 and the turbine unit 13 eliminates its losses and, therefore, eliminates the need for constant monitoring and replenishment of its volume.

The heat exchanger of the turbine unit 13 transfers the "waste" heat for space heating. At a moderate outdoor temperature, it can operate in an open circuit, thereby providing enhanced ventilation of the premises. With cooling, this circuit can be partially or completely closed. And in especially cold weather (or at reduced energy consumption), you can add heat directly from the heat accumulator 1. In the summer, you can use heat from the heat exchanger of the turbine unit for other needs (hot water supply, drying of materials, products, use of a sauna, pool, etc. P.).

The inventive device, presented in the described complex, is compact, easy to design and easy to use, low noise of both a wind turbine and a turbine, complete environmental safety, relatively low capital costs. All this should ensure the mass demand for such installations in solving the increasingly acute problem of autonomous energy supply of such facilities as individual housing, small-scale agricultural production, crafts, remote health facilities or environmental facilities and tourism, and will solve vital infrastructure problems in the development and settlement of new territories will improve living conditions in preserved rural settlements.

Claims (1)

A microthermal electric center operating on renewable energy sources (RES), having a steam generator made in the form of a steam boiler and superheater, a steam turbine, an electric generator, a condensate return device and a heat exchanger, characterized in that the steam boiler and the superheater have a heat accumulator with a heat source as an energy source resource from renewable energy sources, the steam boiler is equipped with a conical or spherical bottom and a buffer tank, the steam turbine is equipped with a system for maintaining the speed at a given Within consisting torque sensor and kinematically associated nozzle device the spool element; the condensate return device is made in the form of a volumetric dispenser, and the heat exchanger is structurally integrated with the turbine unit housing.

Images