JP2009299532A - Co-generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a co-generation apparatus that improves total efficiency, in particular, power generation efficiency. <P>SOLUTION: This co-generation apparatus 10 includes at least a power generation unit 24 comprising a generator 20 connectable to a power supply passage 16 of AC electric power from a commercial power source 12 to an electric load 14 and an engine 22 for driving the generator, a heat exchanger for exchanging heat between the cooling water and the exhaust heat of the engine for raising a temperature, a cooling water passage 42c for connecting the heat exchanger 26 to the engine and supplying the cooling water outputted from the heat exchanger to the engine , and an exhaust passage 22h connected to the engine for discharging exhaust gas outputted from the engine. The co-generation apparatus is provided with a thermo-electric generating element 46 for generating power according to a temperature difference. A low temperature part 46a of the thermo-electric generating element 46 is brought in proximity to the cooling water passage 42c, and a high temperature part 46b of the thermo-electric generating element 46 is brought in proximity to the exhaust passage 22h. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cogeneration apparatus, and more particularly to a cogeneration apparatus that improves power generation efficiency.

In recent years, a power generation unit consisting of a generator driven by an internal combustion engine is connected to an AC power supply path from a commercial power system to an electrical load, and the power generated by the power generation unit (electric energy) is linked to the commercial power system. A so-called cogeneration apparatus has been proposed in which hot water or the like (heat energy) generated by utilizing exhaust heat from an internal combustion engine is supplied to the heat load (see, for example, Patent Document 1). ).
JP-A-8-4586

  By the way, in the above-mentioned cogeneration apparatus, about 22.5% of the energy of the fuel of the internal combustion engine is converted into electric energy, and about 62.5% is converted into heat energy, and electric load or heat load is converted. The total efficiency reaches 85.0%, but in order to make more effective use of energy, it is desired to improve the overall efficiency, especially the conversion efficiency into electric energy (power generation efficiency). ing. However, the technique described in Patent Document 1 described above has not been disclosed at all in that respect.

  Accordingly, an object of the present invention is to provide a cogeneration apparatus that solves the above-described problems and improves the overall efficiency, in particular, the power generation efficiency.

  In order to solve the above-described problem, in claim 1, a generator that can be connected to an AC power supply path from a commercial power system to an electric load, and a power generation unit that includes an internal combustion engine that drives the generator, A heat exchanger that heats the cooling water of the internal combustion engine by exchanging heat with exhaust heat, and the cooling water that is output from the heat exchanger by connecting the heat exchanger and the internal combustion engine to the internal combustion engine. A cogeneration apparatus comprising at least a cooling water passage for supplying air to an internal combustion engine and an exhaust passage for discharging exhaust gas output from the internal combustion engine is provided with a thermoelectric generator that generates electric power according to a temperature difference At the same time, the low temperature portion of the thermoelectric generator is placed close to the cooling water passage, while the high temperature portion of the thermoelectric generator is arranged close to the exhaust passage.

  In the cogeneration apparatus according to the second aspect, the low temperature portion of the thermoelectric generator is arranged in the vicinity of the position immediately after the cooling water passage exits the heat exchanger.

  In the cogeneration apparatus according to a third aspect of the present invention, the high temperature portion of the thermoelectric generator is arranged close to the position immediately after the exhaust passage leaves the internal combustion engine.

  The cogeneration apparatus according to claim 1 is provided with a thermoelectric generator that generates electric power in accordance with a temperature difference, and cooling that supplies a low-temperature portion of the thermoelectric generator to the internal combustion engine with cooling water output from the heat exchanger The thermoelectric generator is arranged close to the water passage while the high temperature portion of the thermoelectric generator is arranged close to the exhaust passage of the internal combustion engine, that is, the thermoelectric generator generates electricity using the temperature difference between the cooling water passage and the exhaust passage. Since it comprised so, the electric power of a thermoelectric generation element can be added to the electric power of an electric power generation unit, ie, the electric power generation amount of an apparatus can be increased, and overall efficiency, especially electric power generation efficiency can be improved.

  In the cogeneration apparatus according to claim 2, the low temperature portion of the thermoelectric generator is located near the position immediately after the cooling water passage exits the heat exchanger, that is, near the position where the temperature is relatively low in the cooling water passage. Since it is configured to be arranged close to each other, in addition to the above-described effects, the temperature difference between the low temperature part and the high temperature part of the thermoelectric generator can be increased, in other words, the power generation amount of the thermoelectric generator can be increased, The power generation efficiency can be further improved.

  In the cogeneration apparatus according to claim 3, the high temperature portion of the thermoelectric generator is brought close to a position immediately after the exhaust passage exits the internal combustion engine, that is, close to a position where the temperature is relatively high in the exhaust passage. In addition to the effects described above, the temperature difference between the low-temperature part and the high-temperature part of the thermoelectric generator can be further increased, so that the amount of power generated by the thermoelectric generator further increases, thereby further improving the power generation efficiency. Can be improved.

  The best mode for carrying out a cogeneration apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram generally showing a cogeneration apparatus according to an embodiment of the present invention.

  In FIG. 1, the code | symbol 10 shows a cogeneration apparatus. The cogeneration apparatus 10 includes a generator (starter / generator) 20 that can be connected to an AC power supply path (power line) 16 from a commercial power source (commercial power system) 12 to an electric load 14 and an internal combustion engine that drives the generator 20. (Hereinafter, referred to as “engine”) 22, an exhaust heat exchanger (heat exchanger) 26 that heats the cooling water of the engine 22 by exchanging heat with exhaust heat, and an exhaust heat exchanger 26. It is provided with a waste heat utilization hot water supply / heating unit (heat load, not shown) that is supplied with cooling water that has been heated to generate hot water or the like.

  The commercial power supply 12 outputs AC power of 50 Hz (or 60 Hz) at 100/200 V AC from a single-phase three-wire. The power generation unit 24 is integrated and housed in the power generation unit case (housing) 30 together with the exhaust heat exchanger 26.

  The engine 22 is a water-cooled four-cycle single-cylinder OHV type spark ignition engine that uses city gas (or LP gas; hereinafter simply referred to as “gas”) as a fuel, and has a displacement of, for example, 163 cc. Although illustration is omitted, in the power generation unit case 30, the cylinder head and the cylinder block 22a of the engine 22 are arranged in a horizontal direction (lateral direction), and one piston is arranged in a reciprocating manner in the inside thereof. A crankshaft (not shown) arranged in the vertical direction (longitudinal direction) is connected to the piston.

  The generator 20 includes a multipole coil, is fixed on a crankcase inside a flywheel (not shown) attached to the upper end of the crankshaft, and generates AC power when rotating relative to the flywheel. . The generator 20 also functions as a starter motor that cranks the engine 22 when energized from the commercial power supply 12 (or a battery (not shown)).

  In the engine 22, air (intake air) enters the mixer 22d through the intake silencer 22b and the air cleaner 22c. Gas is supplied to the mixer 22d from a fuel supply source (not shown) through the gas pipe 32 and the gas proportional valve unit 22e, where it is mixed with air. In the gas box including the mixer 22d and the gas proportional valve unit 22e, the mixer 22d includes a throttle valve driven by an electric motor and a variable jet.

  The air-fuel mixture generated by the mixer 22d flows into a combustion chamber (not shown). A spark plug 22f is disposed in the vicinity of the combustion chamber. When the output of a battery (not shown) is supplied via an ignition device 22g composed of a power transistor, an ignition coil, or the like, the spark plug 22f generates a spark discharge between the electrodes facing the combustion chamber, ignites the air-fuel mixture, and burns it. . Thus, the generated exhaust gas (exhaust gas) is output from the engine 22, and is discharged out of the power generation unit case 30 (outside the warehouse) through an exhaust passage (exhaust pipe) 22h connected to the engine 22 and an exhaust muffler 22i.

  An oil tank (oil pan) 22k is formed below the cylinder block 22a of the engine 22 (the crankcase is not shown), and the lubricating oil of the engine 22 is stored therein. Lubricating oil is scraped up by a gear pump (not shown) and lubricates a sliding portion such as a piston, then drops along a connecting rod (not shown) and a cylinder wall surface, and is stored in an oil tank 22k.

  The output of the generator 20 is sent to the inverter unit 34. The inverter unit 34 converts the output of the generator 20 into AC 100/200 V (single phase) via a DC-DC converter or the like. The inverter unit 34 constitutes a control unit together with an ECU (Electronic Control Unit) 36 composed of a microcomputer, and switches the function of the generator 20 between the starter and the generator in response to an instruction from the ECU 36.

  The output of the inverter unit 34 is sent to the indoor switchboard 40. The indoor switchboard 40 includes a main circuit breaker 40a that prevents overcurrent and the like, a distribution board 40b that adds the power of the commercial power supply 12 to the output of the inverter unit 34 and supplies it to the electric load 14, and a dedicated breaker for the power generation unit 24. 40c, and a current sensor 40d that is disposed in the power supply path 16 from the commercial power supply 12 to the main breaker 40a and generates a signal corresponding to the current of AC power flowing therethrough. That is, the output of the inverter unit 34 is combined with (connected to) the electric power of the commercial power supply 12 by the indoor switchboard 40 and supplied to the electric load 14.

  As described above, the output of the inverter unit 34 can be connected to the AC power supply path 16 from the commercial power supply 12 to the electric load 14 by the indoor switchboard 40. The power generation output (rated power) of the power generation unit 24 is about 1.0 kW.

  The cogeneration apparatus 10 includes a number of sensors as shown in FIG. 1 in addition to the above-described current sensor 40d, and the output of each sensor is input to the ECU 36. The ECU 36 controls the operation of the engine 22 and the like based on the input output, but the control is not directly related to the present application, and thus the description thereof is omitted.

  Reference numeral 42 indicates a passage of cooling water (antifreeze) for cooling the engine 22 (hereinafter referred to as “cooling water passage”). The cooling water passage 42 passes through the cylinder block 22a of the engine 22, the oil tank 22k, and the exhaust heat exchanger 26, and is connected to an external exhaust heat utilization hot water supply / heating unit (hereinafter simply referred to as “heating unit”).

  The cooling water passage 42 will be described in detail. The cooling water passage 42 connects the heating unit and the oil tank 22k, and supplies a low-temperature cooling water output from the heating unit to the oil tank 22k. A second cooling water passage 42b for connecting the oil tank 22k and the exhaust heat exchanger 26 to supply the cooling water output from the oil tank 22k to the exhaust heat exchanger 26, the exhaust heat exchanger 26 and the cylinder of the engine 22 A third cooling water passage (cooling water passage) 42c that connects the block 22a and supplies the cooling water output from the exhaust heat exchanger 26 to the cylinder block 22a, and the cylinder block 22a and the heating unit are connected to the cylinder block. The fourth cooling water passage 42d supplies (returns) the high-temperature cooling water output from 22a to the heating unit.

  Accordingly, the low-temperature cooling water sent from the heating unit is guided to the inlet side 42e of the cooling water passage 42, and is supplied to the oil tank 22k by the circulation pump 44 via the first cooling water passage 42a. In the oil tank 22k, the cooling water passes through a tank passage formed in the oil tank 22k to exchange heat with the lubricating oil to cool the lubricating oil, and then is disposed in the exhaust passage 22h through the second cooling water passage 42b. The exhaust heat exchanger 26 is supplied.

  In the exhaust heat exchanger 26, the cooling water is heated up by exchanging heat with the exhaust gas (exhaust gas). The exhaust heat exchanger 26 has a structure in which, for example, the cooling water passage 42 is deformed to cover the exhaust passage 22h. The cooling water that has passed through the exhaust heat exchanger 26 is supplied to the cylinder passage formed in the cylinder block 22a (and the cylinder head) via the third cooling water passage 42c to exchange heat with the engine 22, Cooling. The high-temperature cooling water that has been heated by heat exchange with the exhaust or the engine 22 is returned to the heating unit from the outlet side 42f through the fourth cooling water passage 42d.

  In the cogeneration apparatus 10, a thermoelectric generator 46 that generates electric power according to a temperature difference is provided between the engine 22 (more precisely, an exhaust valve of the cylinder head of the engine 22) and the exhaust heat exchanger 26.

  Hereinafter, the thermoelectric generation element 46 and the position where the thermoelectric generation element 46 is provided will be described in detail.

  FIG. 2 is an exploded perspective view showing a power generation unit case 30 in which the power generation unit 24, the exhaust heat exchanger 26 and the like shown in FIG. 1 are accommodated. 3 is a partially enlarged view showing a portion surrounded by a broken line in FIG. 2, and FIG. 4 is a sectional view in the vicinity of a position where the thermoelectric generator 46 shown in FIG. 3 is arranged. In FIG. 3, for convenience of understanding, a part of the exhaust passage 22h is removed. 3 and 4, the flow of the cooling water is indicated by a thick black arrow, and the flow of the exhaust gas is indicated by a thick white arrow.

  As shown in FIG. 2, the power generation unit case 30 includes an outer wall panel 50, and the above-described power generation unit 24, the exhaust heat exchanger 26, and the like are accommodated in an internal space formed by the outer wall panel 50. Specifically, the exhaust heat exchanger 26 and the like are disposed at a position below the power generation unit case 30 in the gravity direction, and at the top of the exhaust heat exchanger 26, in other words, at the center position of the power generation unit case 30. The engine 22 and the generator 20 are installed. An air cleaner 22c, a muffler 22i, and the like are attached to the upper position of the power generation unit case 30. Note that the thermoelectric generator 46 is not visible in FIG.

  The thermoelectric generator 46 has a flat plate shape as shown in FIGS. As shown in FIG. 4, the thermoelectric generator 46 is made of a metal material, and is cooled to be cooled to lower the temperature 46 a, the heated portion 46 b to be heated, and the low temperature portion 46 b to be heated. The semiconductor element 46c is inserted between the p-type thermoelectric semiconductor (not shown) and the n-type thermoelectric semiconductor alternately connected in series. That is, the thermoelectric generator 46 is a known thermoelectric generator module that uses the Seebeck effect of generating electric power according to the temperature difference between the low temperature portion 46a and the high temperature portion 46b, and detailed description thereof is omitted.

  The thermoelectric generator 46 is disposed between the engine 22 and the exhaust heat exchanger 26 and close to the exhaust passage 22 h of the engine 22 and the cooling water passage 42 of the exhaust heat exchanger 26. Specifically, as shown in FIG. 4, the low temperature portion 46 a of the thermoelectric generator 46 is close to the cooling water passage 42 (more precisely, the third cooling water passage 42 c connecting the exhaust heat exchanger 26 and the engine 22). The high temperature portion 46b of the thermoelectric generator 46 is disposed close to the exhaust passage 22h. The separation distance L1 between the low temperature portion 46a of the thermoelectric generator 46 and the third cooling water passage 42c is set to such a distance that the low temperature portion 46a can be cooled by the third cooling water passage 42c. Similarly, the separation distance L2 between the high temperature portion 46b of the thermoelectric generator 46 and the exhaust passage 22h is set to such a distance that the high temperature portion 46b can be heated by the heat from the exhaust passage 22h.

  More specifically, the positions of the third cooling water passage 42c and the exhaust passage 22h in which the thermoelectric generation element 46 is disposed will be described. As shown in FIG. The cooling water passage 42c is disposed in the vicinity of the position immediately after exiting the exhaust heat exchanger 26 (indicated by reference numeral 42c1 in the figure). That is, the low temperature part 46a is arranged in the vicinity of a position where the temperature is relatively low in the third cooling water passage 42c.

  On the other hand, the high temperature portion 46b of the thermoelectric generator 46 is in the vicinity of the position immediately after the exhaust passage 22h leaves the engine 22 (indicated by reference numeral 22h1 in the figure), in other words, in the vicinity of the exhaust valve (not shown) of the engine 22. Is placed close to. That is, the high temperature portion 46b is disposed in the vicinity of the position where the temperature is relatively high in the exhaust passage 22h.

  By disposing the thermoelectric generator 46 at the above-described position, the low temperature portion 46a is cooled by the third cooling water passage 42c and becomes low temperature, while the high temperature portion 46b is heated by the exhaust passage 22h and becomes high temperature. Thereby, a temperature difference arises between the low temperature part 46a and the high temperature part 46b of the thermoelectric generation element 46, and electric power generation is performed according to the temperature difference (proportional). Specifically, when the temperature difference between the low temperature portion 46a and the high temperature portion 46b is, for example, 70 ° C. and 650 ° C. and the temperature difference is 580 ° C., the thermoelectric generator 46 can output DC power of about 30 W.

  Further, since the thermoelectric generator 46 is disposed between the third cooling water passage 42c and the exhaust passage 22h, the third cooling water passage 42c can be prevented from cooling the exhaust passage 22h. Therefore, the temperature of the exhaust gas flowing through the exhaust passage 22h is not lowered by the third cooling water passage 42c, and hence the subsequent heat exchange in the exhaust heat exchanger 26 can be performed efficiently, that is, the overall efficiency. Can be improved.

  As shown in FIG. 1, the output (DC power) of the thermoelectric generator 46 generated as described above is input to the inverter unit 34 through the power line 52, where it is combined with the output of the generator 20 described above. Thereafter, the electric load 14 is supplied through the dedicated breaker 34c, the distribution board 34b, and the like.

  As described above, in the embodiment of the present invention, the generator (starter / generator) 20 that can be connected to the AC power supply path 16 from the commercial power system (commercial power source) 12 to the electric load 14 and the generator A power generation unit 24 comprising an internal combustion engine (engine) 22 that drives the engine, a heat exchanger (exhaust heat exchanger) 26 that heats the cooling water of the internal combustion engine by exchanging heat with exhaust heat, and the heat exchanger A cooling water passage (third cooling water passage) 42c for connecting the internal combustion engine to supply the cooling water output from the heat exchanger to the internal combustion engine, and a connection to the internal combustion engine from the internal combustion engine. In the cogeneration apparatus 10 having at least an exhaust passage 22h for discharging exhaust gas to be output, a thermoelectric generation element 46 that generates electric power according to a temperature difference is provided, and the low temperature portion 4 of the thermoelectric generation element 46 is provided. While to close a to the cooling water passage 42c, and as configured to arrange the high-temperature portion 46b of the heat generating element 46 in close proximity to the exhaust passage 22h.

  As described above, since the thermoelectric generator 46 generates power using the temperature difference between the third cooling water passage 42c and the exhaust passage 22h, the electric power of the thermoelectric generator 46 is added to the electric power of the power generation unit 24. That is, the power generation amount of the cogeneration apparatus 10 can be increased, and thus the overall efficiency, particularly the power generation efficiency can be improved.

  Further, the low temperature portion 46a of the thermoelectric generator 46 is arranged so that the cooling water passage (third cooling water passage) 42c is disposed in the vicinity of the position 46c1 immediately after leaving the heat exchanger 26. That is, since the low temperature portion 46a of the thermoelectric generator 46 is arranged in the vicinity of the position where the temperature is relatively low in the third cooling water passage 42c, the low temperature portion 46a and the high temperature portion of the thermoelectric generator 46 are arranged. The temperature difference of 46b can be increased, in other words, the power generation amount of the thermoelectric generator 46 can be increased, and the power generation efficiency can be further improved.

  Further, the high temperature portion 46b of the thermoelectric generator 46 is arranged so that the exhaust passage 22h is close to the vicinity of the position 22h1 immediately after leaving the internal combustion engine (engine) 22. That is, since the high temperature portion 46b of the thermoelectric generator 46 is arranged in the vicinity of the position where the temperature is relatively high in the exhaust passage 22h, the temperature difference between the low temperature portion 46a and the high temperature portion 46b of the thermoelectric generator 46 is determined. Therefore, the amount of power generated by the thermoelectric generator 46 can be further increased, and the power generation efficiency can be further improved.

  In the above, the output of the thermoelectric generator 46 is configured to be input to the inverter unit 34. However, the present invention is not limited to this. For example, the output is directly input to an indicator on an operation panel (not shown). You may comprise so that it may be used as electric power.

  Moreover, although the drive source of the generator 20 is a gas engine using city gas / LP gas as fuel, an engine using gasoline fuel or the like may be used. Moreover, although the rated output of the power generation unit 24, the displacement of the engine 22 and the like are shown as specific values, these are examples and are not limited.

  In the embodiment, the AC power output from the commercial power source 12 is set to 100 / 200V. However, when the AC power output from the commercial power source 12 exceeds 100 / 200V, the corresponding voltage is output from the power generation unit 24. Needless to say.

1 is a block diagram generally showing a cogeneration apparatus according to an embodiment of the present invention. It is a disassembled perspective view which shows the electric power generation unit case in which the electric power generation unit etc. which were shown in FIG. 1 were accommodated. It is the elements on larger scale which expand and show the part enclosed with the broken line in FIG. It is sectional drawing of the position vicinity of the thermoelectric power generation element shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Cogeneration apparatus, 12 Commercial power supply (commercial power system), 14 Electric load, 16 Feeding path, 20 Generator (starter / generator), 22 Engine (internal combustion engine), 22h Exhaust passage, 24 Power generation unit, 26 Exhaust heat exchange (Heat exchanger), 42c third cooling water passage (cooling water passage), 46 thermoelectric generator, 46a (thermoelectric generator) low temperature section, 46b (thermoelectric generator) high temperature section

Claims (3)

  A generator that can be connected to an AC power supply path from a commercial power system to an electric load and an internal combustion engine that drives the generator, and the cooling water of the internal combustion engine is heat-exchanged with exhaust heat to raise the temperature. A heat exchanger that connects the heat exchanger to the internal combustion engine and supplies the cooling water output from the heat exchanger to the internal combustion engine, and the internal combustion engine that is connected to the internal combustion engine. A cogeneration apparatus having at least an exhaust passage for discharging exhaust gas output from an engine is provided with a thermoelectric generation element that generates electric power according to a temperature difference, and a low temperature portion of the thermoelectric generation element is brought close to the cooling water passage On the other hand, the cogeneration apparatus is characterized in that the high temperature portion of the thermoelectric generator is disposed close to the exhaust passage.   2. The cogeneration apparatus according to claim 1, wherein the low temperature portion of the thermoelectric generator is disposed close to a position immediately after the cooling water passage exits the heat exchanger.   The cogeneration apparatus according to claim 1 or 2, wherein the high temperature portion of the thermoelectric generator is disposed close to a position immediately after the exhaust passage leaves the internal combustion engine.

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