DE102008045309A1 - Block-type heating power plant for production of current and power for e.g. multi-family house, has control device for controlling generator for variable partitioning of power delivered from fuel drive into current and heat - Google Patents

Abstract

The plant (2) has a fuel drive (10) connected with a generator (12), and a control device arranged on the generator. The control device controls the generator for variable partitioning of power delivered from the fuel drive into current and heat. The control device is connected with a power and voltage conversion device. An exhaust gas temperature detection unit detects exhaust gas temperature, where detection signals are supplied to the control device. The control device regulates power output of the fuel drive. An independent claim is also included for a method for operating a block-type heating power plant.

Description

Technical area

The The invention relates to a combined heat and power plant for generating electricity and heat, especially for a single or multi-family house or for small businesses, as well as a Method for operating a corresponding combined heat and power plant. The cogeneration plant according to the invention is with a fuel drive and one with the fuel drive operatively connected generator and a control device fitted.

State of the art

cogeneration for generating electricity and heat energy are known in the art. The known combined heat and power plants become dependent distinguished from their purpose in different performance classes. In the past, the combined heat and power plants for private households regularly as Settlement power plants designed which provide enough heat and energy for several homes or Housing units provided. Such cogeneration plants are based on different engine concepts, mostly using fossil or vegetable fuels such as diesel, vegetable oil or wood.

Of the Operation of the corresponding cogeneration units has become due the high maintenance costs have not proved particularly profitable. It has been recognized that cogeneration units for smaller units, so-called. Mini combined heat and power plants, especially for single or multi-family houses, more profitable could be.

One Problem is, however, that also on the combustion various fuels based small or mini combined heat and power plants like all Internal combustion engines regular maintenance have to be subjected so that they run properly.

One Another disadvantage is that the operating phases of the fuel drives The mini cogeneration plants are usually relatively short, so this often in and out Operation must be taken. This increases however, the wear and tear the maintenance effort.

One Another disadvantage of the known combined heat and power plants is that that these consist of many components, which all for themselves Defect risk, the probability of default and thus the repair and maintenance costs increased.

One Another disadvantage of the known from the prior art mini cogeneration units is that their motors are operated at a speed have to, those with the grid frequency, usually between 50 and 60 Hz, in integer context. Most MCHP units are therefore the three-phase of the discharged stream because of Crankshaft speeds of 1,500 rpm. or 3,000 rpm. operated. Of the optimal working point often used diesel engines of mini combined heat and power plants is located in for example, between the aforementioned speeds, so known mini combined heat and power plants can not be operated with the optimum efficiency. This reduces their profitability.

Last exists in the known from the prior art mini cogeneration units the disadvantage that these are regularly a Fixed distribution of power output in electricity and heat energy exhibit. The electricity and heat demand fluctuates However. So there are times during a day when a lot of heat and little power needed is, for example, in the morning or evening much hot water personal hygiene is taken or phases in which a lot of electricity, but correspondingly less heat needed For example, at lunchtime, when stoves and hobs are in operation are.

task

task The invention is a combined heat and power plant and a method to indicate the operation of a combined heat and power plant, which from the state overcomes the technology resulting disadvantages.

task In particular, it is a combined heat and power plant and a method for To specify the operation of a cogeneration plant, in which the number of required components across from usual Combined heat and power plants is significantly reduced.

A Another object is a combined heat and power plant and a method to indicate the operation of a combined heat and power plant whose maintenance cycles compared to conventional Combined heat and power plants are considerably extended.

A Another object is a combined heat and power plant and a Specify method for operating a combined heat and power plant, the preferably operable in each optimal operating point of the fuel drive is.

A final object of the invention is to provide a combined heat and power plant and a method for operating a combined heat and power plant, in which an optimal power output, depending on a current need for electricity and / or heat nergy is possible.

Presentation of the invention

The Task is solved by a combined heat and power plant according to claim 1 and by a method for operating a combined heat and power plant according to the sibling Claim 12. Advantageous embodiments of the invention are the subject the dependent claims.

One inventive cogeneration plant has a fuel drive and one with the fuel drive in operative connection standing generator on, the kinetic energy of the fuel drive converted into electrical energy. An inventive combined heat and power plant is particularly suitable for use in single or multi-family homes, in particular smaller apartment buildings with up to four residential parties.

Under a fuel drive according to the invention is a drive to understand which derives its energy from the utilization of fuels. Eligible Fuels are for example fossil fuels such. Gasoline or diesel and vegetable fuels such as vegetable oil or wood. Other eligible fuels include gaseous fuels such as hydrogen, gas, especially natural gas, and the like. The drives according to the invention can Piston engines, Sterling engines, Wankel engines or general engines be, which include an output shaft. Piston engines have the Advantage that these z. B. in vehicles for a long time in huge numbers used and therefore are very reliable. These piston engines can with separate ignition, for example, gasoline engine, as well as a diesel engine, for example diesel engine, be educated.

The inventive cogeneration plant has a control device acting on the generator. These Effect can be direct or indirect. The control device is designed to control the generator to that of the fuel drive delivered power variable in power and heat output divide. For this purpose, in particular, be provided, the torque of the generator, ie the resistance generated by the generator, to vary. A preferred option For this purpose, the adaptation of the reactive power component of the generator sees in front.

The converted into reactive power heat energy can according to a Development of the invention dissipated and as heat output be used.

Farther let yourself with such connected to the device for current and voltage conversion Control device determine the speed of the fuel drive. In this way can be dispensed with speed sensor on the fuel drive become.

There the fuel drives waste heat produce and often also cooled can, preferably, a heat exchanger be provided with the released of the waste heat heat energy a heat storage, which is connected to the cogeneration plant to be discharged can.

Prefers a device for current and voltage conversion is provided, which is connected to the generator. That way you can to implement the necessary regulations particularly easily, as with Help such a device, the torque of the generator adjustable is.

To a particularly advantageous development, the device for current and voltage conversion a frequency converter. Such frequency converter can by Adjustment of operating parameters set a torque on the generator and thereby the variable distribution of the fuel drive Delivered power in electricity and heat realize. Furthermore can they generate a DC voltage from the AC voltage of the generator. The device for current and voltage conversion can continue a regenerative unit exhibit.

Prefers is the control device with the device for power and Voltage conversion connected. In this way, the generator can be special handle well.

If the generator continues through the device for current and voltage conversion and by the control device as a starter of the fuel drive is operable leaves to achieve the advantage that no separate starter for the fuel drive is required. In this way, the complexity of the combined heat and power plant can be reduced and increase reliability. To the power supply of the cogeneration plant in starter operation can either be an existing Power supply can be used when the cogeneration plant z. B. is intended to provide electricity in a power grid, such as a public Power supply, or it can be an optional battery or an optional accumulator may be provided. Especially in industrial nations are combined heat and power plants according to the invention often used to feed electricity back into the grid, what the other Advantage that brings on a battery or an accumulator can usually be dispensed with in these regions.

To use the generator as a starter of the fuel drive, the device for Current and voltage conversion via the control device controlled such that a current flow from the device for current and voltage conversion takes place towards the generator, so that it operates as a motor.

To A preferred embodiment of the invention is provided that the device for current and voltage conversion for generating a AC power with a predetermined or predetermined output frequency independently is formed by the input frequency of the current. To this Way is achieved that the drive always in the optimal point of effect is operated without any consideration must be taken to a necessary output frequency. Furthermore lets up this way the combined heat and power plant without conversion measures to different Use purposes, for example, to provide two- or three-phase Current with, for example, 50 or 60 Hz. Particularly preferred this by a combination of a frequency converter with a regenerative unit realized.

To A further advantageous embodiment provides that the control device acts on the fuel drive. To this Manner, operating parameters of the fuel drive with the Regulate control device. Preferably can be with the help of the control device regulate the power output of the fuel drive. This can be done For example, gasoline, gas or diesel engines by regulation the fuel supply happen. That way you can on the one hand set the output power of the fuel drive and on the other hand, the speed at which the fuel drive operated becomes. To adjust the speed can continue to torque or the resistance of the generator can be adjusted.

If Furthermore means for detecting the heat demand and / or the electrical Power requirements are provided, the signals of the control device supplied are, lets a particularly useful power distribution and commissioning reach the cogeneration plant. So, for example, at presence a heat accumulator connected to the combined heat and power plant when the demand for electricity drops and the amount of heat is low in the heat storage, for example, the temperature of a return the connection to the heat storage to recognize the combined heat and power plant remain in operation and the power generated to the largest possible Part in heat output implement. The commissioning of the cogeneration plant is therefore less often required. In this way, the operating cycles can be extended since every commissioning a higher Wear conditional.

To Another embodiment of the invention are means for detection an exhaust gas temperature provided, the signals of the control device supplied are. The exhaust gas temperature of the fuel drive should be one of depending on the type of drive Do not leave the temperature range, for example, a sooting of the To prevent engines. With the help of an exhaust gas temperature sensor, this can be prevented. Thus, when the exhaust gas temperature drops, the Reduced speed of the fuel drive and the torque of the Generators increased which results in the same performance per cycle more fuel must be burned, reducing the exhaust gas temperature increases.

One another advantage reach when a preheater for preheating the fuel drive is provided. For this purpose, for example, on used an electric preheater which in the case of a grid connection of the combined heat and power plant can be supplied with mains power. If such a network connection not available stands, the preheater can For example, be a burner, the fuel used recycled.

Prefers are the generator or device for current and voltage conversion with a controllable or variable conversion device electrical energy in heat connected. In this way, the reactive power used in the scheme the fuel drive drops, as heat energy be used.

Of the Fuel drive according to the invention can have further constituents, for example smoothing throttles for smoothing the generated AC or when an injection of the generated Electricity is provided in a network, necessary components, such as network quality sensors or synchronization components.

Of Further can be provided with preference means, with which use the engine waste heat leaves. That way increase the efficiency. Furthermore, it can be provided with preference that the heat energy over a heat exchangers is deliverable.

One Another particular advantage arises when the cogeneration plant a device for automatic lubricant change, in short: lubricant change device, having. Such a device allows the increase of Operating life of the combined heat and power plant, without the need of Maintenance considerably. Such lubricants are common liquid Lubricants, such as lubricating oils, as are common in fuel drives.

The The device has a fresh medium reservoir which is connected to an operating lubricant circuit the fuel drive is connected. Furthermore, an old lubricant reservoir or used lubricant reservoir provided, also connected to the fuel drive.

to Connection of the fresh lubricant reservoir with the operating lubricant circuit is a Feed provided for the connection of the waste lubricant reservoir with the Operating lubricant circuit a drain. Inlet and outlet can as connecting hoses or other supply lines may be formed.

to Shut-off of inlet and outlet are each provided shut-off, with which a feed of fresh lubricant and a drain of Operating lubricant can be prevented.

Of Furthermore, control means for controlling the shut-off means are provided.

With Help the lubricant change device is thus an automatic Lubricant change in a particularly simple manner possible, in dependent Lubricant is refillable or replaceable by certain parameters. The user of the combined heat and power plant then only needs lubricant refill and used lubricant from the used lubricant reservoir remove, as long as no other maintenance work on the cogeneration plant attack. In this way, the operation of the combined heat and power plant be performed without intervention by the user for a long time. In the combined heat and power plant according to the invention can operate in this way for many months without Maintenance allows so that the acceptance of such combined heat and power plants also in the private sector is increasing. Furthermore, with the help of the device prevents the lubricant level inside the device falls below a minimum amount and the lubricant-carrying device Takes damage.

The Device is particularly in existing lubricant leading Devices can be retrofitted and can enhance the functionality of existing devices contribute.

According to one Further development of the lubricant device is provided that the shut-off means are automatically operable valves. such Valves have proven to be particularly reliable and allow the reduction of the required components to provide the Device, since no further means for actuating the valves are required.

When Particularly suitable solenoid valves have proven that with control electrical control commands.

The Schmiermittelprüfvorrichtung is preferred as a lubricant level sensor and / or as a lubricant quality testing device educated. With the help of a lubricant level sensor can be the Determine the lubricant level of the fuel drive particularly easily. The lubricant level sensor is in the presence of an operating lubricant reservoir the fuel drive preferably for attachment to the corresponding operating lubricant reservoir educated. A preferred embodiment of the lubricant level sensor is a swimmer who has proven to be particularly reliable and accurate especially in stationary Devices.

If the lubricant tester as a lubricant quality tester is formed, for example a device, the chemical composition, Conductance and / or turbidity In addition, a lubricant change can be analyzed then be made if the lubricant quality a Minimum standard falls below. Thus, a lubricant change always be done at the optimal time.

The Schmiermittelprüfvorrichtung is preferably designed for arrangement in a bypass, the z. B. from an operating lubricant reservoir of the fuel drive branches. Such a bypass allows easy access to the operating agent of the fuel drive.

Prefers is the control for detecting the operating time of the fuel drive educated. In the operating time can be differentiated between the absolute operating time of the fuel drive and the operating time since certain events, for example the last lubricant replenishment and / or since the last lubricant change. This way you can Lubricant change dependent be made by the residence time of the lubricant in the operating lubricant circuit. About that In addition, lubricant loss can be detected when refilling lubricants too often is required.

A further preferred embodiment of the lubricant changeover device provides that the fresh lubricant reservoir holds a larger volume of lubricant than the waste lubricant reservoir. In this way it can be achieved that at a lubricant change first the waste lubricant reservoir is filled before the fresh lubricant reservoir is empty. This prevents that with a necessary change of lubricant no fresh lubricant is present and the fuel drive fails until the lubricant is replenished. In particular, in combined heat and power plants is thus prevented that, for example, in winter, the device fails at a particularly unfavorable time and neither electricity nor heat can be produced. At least one operating cycle is then still possible before the emptying of the waste lubricant reservoir and the replenishment of fresh lubricant are required.

If the fresh lubricant reservoir for placement above the operating lubricant circuit and / or the waste lubricant reservoir for placement below the operating lubricant circuit are formed, can Pumps for transport be dispensed with lubricant, since the lubricant due to gravity promoted become.

Farther can be provided, a rotary or circulation pump for cooling the Fuel drive to use. In this way, it is possible to have a fault-prone V-belt driven pump be waived.

One another independent The invention relates to a method for operating a combined heat and power plant, in particular one according to the above described invention. According to the invention it is provided that a determined by the cogeneration plant to be provided heat and electricity demand and a fuel drive of the combined heat and power plant to the delivery the required total power is operated, the distribution of Total power in electricity and heat via a scheme made of an operatively connected to the fuel drive generator becomes. Of course the total power must be high enough to compensate for power losses become. That way specify a particularly flexible cogeneration plant, in which, depending on the current electricity and heat demand, the distribution of power on electricity and heat can be varied. So a combined heat and power plant can always be operated with high efficiency be because of power or heat losses let reduce. Furthermore, the operating cycles of the Extend combined heat and power plant, which increases the life of the combined heat and power plant.

To A first advantageous embodiment provides that the Commissioning of the fuel drive by means of the generator is started. In this way, can be dispensed with a separate starter.

Farther may be provided with preference that the fuel drive before is preheated to a starting temperature for starting. That way you can the particularly wear-prone cold start prevent the fuel drive, what the life of the fuel drive benefits.

If Furthermore, it is provided that one with the control device and device for current and voltage conversion connected to the generator, in particular a frequency converter, for the distribution of the total power in electricity and heat through Adjustment of a generator torque is made, can be reach the regulation particularly easily, since with the help of such a current and voltage conversion device by adjusting a reactive power Electricity and heat emission can be adjusted very easily. With the help of such Device leaves Operation of the generator as a starter is particularly easy to realize.

Prefers An exhaust gas temperature of the fuel drive is detected and a Regulation of the fuel drive via a control of the speed of the fuel drive and / or the Power output of the fuel drive made. To this Way lets one as possible unequal exhaust gas temperature even at low load, For example, in which reduces the speed of the fuel drive which automatically increases the exhaust gas temperature.

preferred Speeds of the fuel drive are between 1700 rpm and 2700rpm, preferably between 2000rpm and 2400rpm, especially preferably at 2200 rpm. In the specified speed ranges is the efficiency of the corresponding drives particularly high.

to Distribution of total power in electricity and heat is calculated according to a Continuing the return temperature a heat system connected to the combined heat and power plant recorded and from this a heat requirement determined. Furthermore or alternatively, to determine the power requirement a power consumption of a supplied from the cogeneration power supply be recorded. In this way, heat and electricity consumption can be particularly easily notice. Furthermore, it is advantageously provided that a Rotational speed of the fuel drive via the device for and voltage conversion is detected. In this way, there are no more Speed sensor required.

To change the lubricant, the combined heat and power plant according to the invention is preferably operated according to the following method. First, it is provided that the lubricant level of the fuel drive and / or the lubricant quality and / or the operating hours of the fuel drive since the last lubricant change and / or since the last lubricant replenishment and / or the fuel drive are detected.

In the case, that a too low level of lubricant is detected in the operating lubricant circuit is, according to the invention automatically lubricant from the fresh lubricant reservoir into the working lubricant reservoir brought. The same applies the case that has been found to be too bad lubricant quality or a specific number of operating hours related to one of the three explained in advance periods is detected.

The Procedure allows automatic refilling and automatic Change of lubricant of the fuel drive, where the lubricant level usually has to have a certain level and where a regular lubricant change dependent required by given criteria.

According to one Continuing the process is used to change the lubricant before Carriage of Lubricant from the fresh lubricant reservoir into the operating lubricant reservoir Used lubricant from the operating lubricant circuit brought into the old lubricant reservoir. This way will achieved a wide exchange of used lubricant.

Around consumed lubricant as much as possible to remove, is provided for a development of the method, that the used lubricant in the lubricant circuit first on a temperature is heated near the operating temperature. This can be done a lower viscosity reach the used lubricant, so that it can drain better. For heating can be provided that the fuel drive put into operation if this is waste heat produced.

Farther is preferred while Discharge of the used lubricant and / or during the refilling fresh lubricant, the lubricant level in the fuel drive to monitor.

Herewith let yourself achieve two things. For one thing lets in the surveillance the lubricant level during of refilling achieve an automatic dosage of lubricant to be replenished. As a result, dosing devices for dosing are refilled Lubricant superfluous.

To the leaves others through supervision the lubricant level when draining lubricant into the Old lubricant reservoir first, monitor the progress of draining and second, notice a full used lubricant reservoir. If the waste lubricant reservoir is full, the lubricant level in the fuel drive decreases not further down. Especially with an already described Development of the device with a larger fresh lubricant reservoir as an old lubricant reservoir can still fresh in this case Filled with lubricant and the fuel drive or the combined heat and power plant one more be operated further operating cycle.

If according to the above described training is provided that the lubricant level monitored during deflation will, according to one Development of the invention issued a message as soon as a full Old lubricant reservoir is detected. This way you can the user of the combined heat and power plant to be displayed when the Old lubricant reservoir must be replaced.

Fresh lubricant reservoir and / or used lubricant reservoir can be considered completely replaceable Be designed modules. Otherwise, the old lubricant reservoir over a Emptying the emptying valve.

Prefers be the lubricant level and / or the lubricant quality after the Switching off the fuel drive, so for example after switching off the fuel drive made. Fuel drives point in usually an operating lubricant reservoir, in which the operating lubricant after switching off the machine usually collects. By measuring after switching off the machine can be a very precise Statement about the lubricant level and / or over the lubricant quality to be hit.

Farther is preferably provided that the supply of fresh lubricant in dosages between 0.5 and 2% of the total operating lubricant volume. In this way, a very accurate metering of operating lubricant be achieved. The dosage can be controlled by a time-controlled opening of the Inlet between fresh lubricant reservoir and operating lubricant circuit respectively. The one for it necessary opening times can be easily determined. It is preferred after each feeding of fresh lubricant from the fresh lubricant reservoir a Lubricant prior measurement performed. Between feeder of fresh lubricant and lubricant level measurement can Preferably, a waiting period can be provided which is sufficient long is to a large extent of the fresh lubricant into the working lubricant reservoir to get to.

Further preferably, the supply amounts of fresh lubricant differ depending on the activity to be performed. When lubricating medium change, the feed quantities can initially be chosen much larger, and when the level approaches a normal level, smaller dosages. When refilling fresh lubricant, smaller dosages are preferable.

Further Objectives, features and advantageous applications of the invention will become apparent from the following description of an embodiment with reference to the Drawings. All are described and / or illustrated features in their meaningful combination the subject matter of the present invention, also independent of the claims and their remittances.

Brief description of the figures

It show schematically:

1 a side view of a cogeneration plant according to the invention;

2 a block diagram of the cogeneration plant according to the invention;

3 a schematic representation of the electrical or electronic components of the cogeneration plant according to the invention;

4 a temperature / speed characteristic as well

5 a power return temperature characteristic.

embodiment

1 shows a cogeneration plant according to the invention 2 in an open side view.

The combined heat and power plant 2 has a housing 4 with a front door 6 and a control panel 8th on. Inside the case 4 is an internal combustion engine 10 provided, which serves for power generation. The internal combustion engine 10 is designed in the present embodiment as a diesel engine, but could also realize another engine concept, in particular a gasoline, gas or Stirling engine.

On an output shaft of the engine 10 is a generator 12 arranged, z. B. flanged, the primary for generating electricity from the motor 10 dissipated kinetic energy is used, which on different, in the 2 and 3 explained components of the combined heat and power plant 2 is converted into mains power of high quality.

The generator 12 also serves to start the engine 10 during the commissioning of the same. This will be the generator 12 by means of a 2 explained control electronics by mains power motor operated, until it is determined by the control electronics that the engine 10 running.

The controller consists of a power unit 14 as well as in a control housing 16 arranged electronic components.

The combined heat and power plant 2 further comprises a device for automatic oil change. This device includes a fresh oil tank 20 and a waste oil tank 22 , The fresh oil tank 20 is above the engine 10 arranged, the waste oil tank 22 below the engine. Oil tank 20 and waste oil tank 22 Both are connected to an oil circuit of the engine 10 connected. The fresh oil tank 20 supplies the engine 10 via a line not shown and a valve, not shown, with fresh oil, whereas used oil of the engine 10 from an oil pan 24 by means of a line 26 and a solenoid valve 28 in the waste oil tank 22 can be drained.

In a bypass, on the oil sump 24 attached is a level gauge 30 arranged. The level gauge 30 works with a swimmer.

About recording the operating time of the engine 10 of the combined heat and power plant 2 as well as a feedback from the level gauge 30 it is possible, used oil of the oil circulation of the engine 10 to replace or completely replace. Unless oil is missing, something through the level gauge 30 after switching off the engine 10 can be detected, can from the fresh oil tank 20 top up with fresh oil until a desired level of filling level is reached.

After a certain period of operation, for example 500 h, an oil change should be made, because during this time the quality of the oil decreases. For this purpose, first the engine 10 brought to operating temperature, whereby the viscosity of the oil in the engine decreases. Subsequently, the solenoid valve 28 opened and the engine oil 10 runs in the waste oil tank 22 from. At the same time the level is measured by the level gauge 30 monitors, so when the depression reaches the valve 28 can be closed again. Then the corresponding valve between fresh oil tank 20 and engine 10 opened so that fresh oil from the fresh oil tank into the engine runs. The level height is also through the level gauge 30 determined and upon reaching the desired level, the valve between fresh oil tank 20 and engine 10 closed.

The supply of fresh oil preferably takes place pulsed, ie with short opening intervals of the valve and intervening measuring pauses. This takes into account the fact that the oil is usually taken from above in the range of a camshaft in the engine and takes a certain time to get into the oil pan 24 has reached where the level measurement is performed.

The combined heat and power plant 2 generated on the one hand via the generator 12 Electricity and on the other hand heat, the heat is generated mainly by the engine heat. To dissipate the heat is the cooling circuit of the engine 10 to a heat exchanger 32 connected, via which the engine heat to a hot water system of the object to be heated, for example, the house is discharged.

The distribution of electricity and heat is via a targeted regulation of the generator 12 that realizes the engine 10 loaded with a torque. In this way, more power is needed in the engine at constant generator speed and more power than waste heat through the heat exchanger 32 dissipated.

The fresh oil tank 20 holds a larger volume than the used oil tank 22 , which achieves that first the waste oil tank 22 completely filled. In this way it can be prevented that when performing an oil change the fresh oil runs out and the cogeneration plant 2 until refilling fresh oil fails.

In 2 is the combined heat and power plant according to the invention 2 shown as a block diagram.

The engine 10 via an output shaft 34 to the generator 12 emitted energy is converted into a dependent of the generator speed AC voltage. This AC voltage is a frequency converter 36 supplied, which converts the AC voltage into a DC voltage.

The converted current becomes a regenerative unit 38 fed, which serves to feed the current back into a public network. The regenerative unit 38 converts from the frequency converter 36 provided DC voltage in an AC voltage of matching voltage and frequency, releases the power to the network and synchronized with the mains voltage. Thus, regardless of the generator speed associated with the engine speed, an alternating current of always constant frequency and selected voltage can be generated.

The regenerative unit 38 converts a three-phase input voltage into a DC voltage and feeds frequency converters 36 individually or via a DC network. It can be switched in parallel if greater feed-in power is required and increases the stability of the DC link voltage in the DC network. The regenerative unit 38 returns surplus energy from regenerative operation to the supply network.

The released current becomes a harmonic filter 40 which filters out higher frequency vibrations as they can be generated by the frequency converter and thus produces a better sinusoidal shape.

After that is another filter 42 provided that improves the electromagnetic compatibility. Last is a backup 44 provided that in case of disturbances the combined heat and power plant 2 takes off the net.

Furthermore, a control unit 46 (PMC) provided, on the one hand, a power requirement of the object that the combined heat and power plant 2 should supply, recorded and takes over all the control operations that are required to control the cogeneration plant. With the help of the PMC 46 becomes the generator 12 mains powered to the motor 10 during commissioning of the combined heat and power plant 2 to start. In addition, by means of the PMC 46 the frequency converter 36 controlled such that the generator is loaded with a predetermined torque.

Furthermore, by the PMC 46 the regenerative unit 38 controlled and a charge of the cogeneration plant 2 generated electricity in a public network.

Another function of the PMC 46 is the distribution of electricity generated in a public network and in the home network. For this purpose, the PMC 46 be programmable, for example, in countries with high feed-back remuneration to allow entry into the home network only if the public network does not provide enough energy.

In addition, the PMC serves 46 to determine a total energy demand and to control the motor, ie for energy supply.

3 shows the structure of the electrical modules in a schematic representation. The generator 12 gives its power according to the selected embodiment, three-phase across the three phases U, V, W to the frequency converter 36 which transforms each phase according to the specifications. The energy is supplied via a DC link provided in the frequency converter 50 to the regenerative unit 38 which synchronizes the power to the mains and to the harmonic filter 40 according to the individual phases L1, L2, L3 forwards. All components are grounded.

4 shows an exhaust gas temperature / engine speed characteristic. On the abscissa the exhaust gas temperature is plotted, on the ordinate the speed of the engine to be set.

The exhaust gas temperature can be subdivided into three areas, an area of ideal exhaust gas temperature, an area of low exhaust gas temperature and an area of high exhaust gas temperature. If the exhaust gas temperatures are too high, the engine components may be damaged and the risk of fire in the vicinity of the exhaust system increases. If the exhaust gas temperatures are too low, there is a risk of sooting the engine 10 ,

To the engine 10 always within the range of optimum exhaust gas temperature, this is monitored in the preferred embodiment. At low load, it may happen that the exhaust gas temperature drops below the desired range. To counteract this, the engine speed of the speed optimum efficiency, in this case 2 200 revolutions per minute, lowered to a lower speed, in this case, for example, 1500 revolutions per minute. At the same time, the generator is operated in such a way that it exerts a torque on the engine, for the compensation of which more gas is given at the same time. This generates more waste heat and the exhaust gas temperature returns to a normal range.

at too high exhaust gas temperature is driven to the contrary. The generator load, So the torque exerted by the generator on the engine, is reduced and the speed of the engine raised, present at about 3,000 revolutions per minute. This ensures that reduces the amount of fuel burned per combustion process and the exhaust gas temperature drops again.

5 shows a characteristic of the engine and he heat output, depending on a return temperature of a heating system. The return temperature is plotted on the abscissa and the powers on the ordinate. In this case, the dashed upper line shows the total power of the combined heat and power plant and the lower solid line shows the power delivered as power. Upon reaching a predetermined return temperature, here 55 degrees, the total power of the combined heat and power plant is exponentially reduced and the power output also reduced exponentially. In this way, significantly less heat is released through the heat exchanger. Thus, it can be achieved that the cogeneration plant as long as possible can be operated without shutdown. As a result, the overall efficiency of the cogeneration plant and its lifetime can be increased.

2

CHP

4

casing

6

door

8th

control panel

10

internal combustion engine

12

generator

14

Electrical power

16

control housing

20

Oil tank

22

Waste oil tank

24

oil pan

26

management

28

magnetic valve

30

level meter

32

heat exchangers

34

output shaft

36

frequency converter

38

Feedback unit

40

Harmonic Filters

42

EMC filters

44

fuse

46

PMC

50

DC

U, V, W

phases

Claims (19)

Combined heat and power plant for generating electricity and heat, in particular for a single or multiple dwelling, with a fuel drive ( 10 ) and one with the fuel drive ( 10 ) operatively connected generator ( 12 ) and one on the generator ( 12 ) acting control device ( 46 ), the control device ( 46 ) for controlling the generator ( 12 ) for variably dividing the fuel drive ( 10 ) output is formed in electricity and heat. Cogeneration plant according to claim 1, characterized in that a device for current and voltage conversion, in particular a frequency converter ( 36 ) and / or a regenerative unit ( 36 ), provided with the generator ( 12 ) connected is. Cogeneration plant according to claim 2, characterized in that the control device ( 46 ) with the device for current and voltage conversion ( 36 . 38 ) connected is. Cogeneration plant according to claim 2 or 3, characterized in that the generator ( 12 ) by the device for current and voltage conversion ( 36 . 38 ) and the control device ( 46 ) as a starter of the fuel drive ( 10 ) is operable. Cogeneration plant according to one of the claims 2 to 4, characterized in that the device for current and voltage conversion ( 36 . 38 ) is designed to generate an alternating current having a predetermined or predefinable output frequency independently of the input frequency. Cogeneration plant according to one of the preceding claims, characterized in that the control device ( 46 ) on the fuel drive ( 10 ) acts, in particular for regulating the power output of the fuel drive. Cogeneration plant according to one of the preceding claims, characterized in that means are provided for detecting the heat demand and / or the electrical power requirement, the signals of the control device ( 46 ) can be supplied. Blockheizkraftwerk according to any one of the preceding claims, characterized in that means are provided for detecting an exhaust gas temperature, the signals of the control device ( 46 ) can be supplied. Cogeneration plant according to one of the preceding claims, characterized in that a preheating device for preheating the fuel drive ( 10 ) is provided. Cogeneration plant according to one of the preceding claims, characterized in that the generator ( 12 ) or the device for current and voltage conversion ( 36 . 38 ) are connected to a controllable device for converting electrical energy into heat. Cogeneration plant according to one of the preceding claims, characterized in that the generator ( 12 ) on an output shaft ( 34 ) of the fuel drive ( 10 ) is arranged. Method for operating a combined heat and power plant ( 2 ), in particular a combined heat and power plant ( 2 ) according to one of the preceding claims, in which one of the combined heat and power plant ( 2 ) to be provided heat and electricity demand is determined and a fuel drive ( 10 ) of the combined heat and power plant ( 2 ) is operated for the delivery of the required total power, wherein the distribution of the total power in electricity and heat via a regulation of one with the fuel drive ( 10 ) operatively connected generator ( 12 ) is made. The method of claim 12, wherein the fuel drive ( 10 ) for commissioning by means of the generator ( 12 ) is started. Method for operating a combined heat and power plant ( 2 ) according to claim 12 or 13, characterized in that the fuel drive ( 10 ) is preheated to a starting temperature before starting. Method for operating a combined heat and power plant ( 2 ) according to claim 14, characterized in that one with the control device ( 46 ) and with the generator ( 12 ) connected device for current and voltage conversion, in particular a frequency converter ( 36 ), to distribute the total power into heat and power by adjusting a generator torque. Method for operating a combined heat and power plant ( 2 ) according to one of claims 12 to 15, characterized in that an exhaust gas temperature of the fuel drive ( 10 ) and a regulation of the fuel drive ( 10 ) via a control of the speed of the fuel drive ( 10 ) and / or the power output of the fuel drive ( 10 ) is made. Method for operating a combined heat and power plant ( 2 ) according to one of claims 12 to 16, characterized in that the fuel drive at speeds between 1700 U / min and 2700 U / min, preferably 2000 U / min to 2400 U / min, more preferably 2200 U / min, operated. Method for operating a combined heat and power plant ( 2 ) according to one of claims 12 to 17, characterized in that for the distribution of the total power in electricity and heat a return temperature () of a to the combined heat and power plant ( 2 ) is detected and from this a heat demand is determined and / or that for determining a power demand, a power consumption of a cogeneration plant ( 2 ) supplied power supply is detected. Method for operating a combined heat and power plant ( 2 ) according to one of claims 12 to 18, characterized in that a rotational speed of the fuel drive via the device for current and voltage conversion ( 36 . 38 ) is detected.