JPH01285646A - Thermoelectric co-supply system adopting gas rotary engine - Google Patents

Abstract

PURPOSE:To reduce pollution, noise, and size of the system in the caption by obtaining electric power while driving a generator by means of a rotary engine, and recovering exhaust heat from the engine and the generator and the like for use of hot water supply, etc. CONSTITUTION:A generator 2 is driven by a gas rotary engine 1 using LPG as fuel, while electric power generated by the generator 2 is supplied inside and outside a package 15. A line 3 which recovers exhaust heat by using circulating water is connected to a plurality of exhaust heat recovering heat exchangers 4-7 arranged inside the package 15 and an absorption refrigerator 8, a hot water reservoir 9, and a radiator 10 arranged outside the package 15 directly in order. The line 3 is also connected through the hot water reservoir 9, an expansion tank 13 and a circulating pump 14 to a jacket cooling part 4 of the engine 1. The exhaust heat from the engine 1 and the generator 2 is effectively adapted to the absorption refrigerator 8 and the hot water reservoir 9 through the heat exchangers 4-7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a relatively small-scale combined heat and power generation system that simultaneously supplies electric power and heat.

[Conventional technology] In recent years, combined heat and power generation systems (cogeneration) have been attracting attention in facilities such as restaurants, pensions, hospitals, and housing complexes that generate electricity through private power generation and also generate thermal energy such as hot water and hot air. ).

By effectively using the waste heat generated during power generation, this system has an energy efficiency of approximately 25 tons when only generating power.
It is possible to increase the total energy efficiency including exhaust heat to about 70 zero or more. Traditionally, among these combined heat and power systems, small ones use a reciprocating engine as the power source to drive a generator and supply electricity.
Heat was recovered from the cooling air of the power plant and generator, the cooling water of the power plant, and the combustion exhaust gas, and the recovered heat was used for hot water supply or space heating.

[Problems to be Solved by the Invention] Combined heat and power generation systems are used in restaurants, pensions, hospitals, and other facilities where large numbers of people gather, and are often installed in places where it is difficult to secure land.

Therefore, the device must not cause environmental pollution such as noise, vibration, or exhaust gas, and it is required to be space-saving.

However, since conventional combined heat and power generation systems use reciprocating engines as power units, the engine mechanism generates a large amount of noise and vibration, making it necessary to install silencers and vibration countermeasure equipment on both sides. In many cases, a nitrification device is required to reduce NOx in exhaust gas.
Not only could it not be made more compact, but it was also economically disadvantageous, and environmental pollution could not be sufficiently eliminated.

Furthermore, reciprocating engines have the disadvantage that they cannot be operated continuously, requiring the engine to be stopped every two to three months for maintenance, particularly for changing lubricating oil.

The present invention solves these problems and uses an engine as a power device that does not cause environmental pollution and can be operated continuously over a long period of time to drive a generator to supply power. The purpose is to provide a compactly packaged combined heat and power generation system that effectively utilizes waste heat generated from equipment and generators.

[Means for Solving the Problems] In order to achieve the above-described object, the combined heat and power system of the present invention includes a rotary engine that is operated using LPG or city gas as fuel, a generator directly connected to the rotary engine, A heat exchanger for recovering exhaust heat from a rotary engine and an exhaust heat recovery line are housed in a package, and the exhaust heat is recovered and effectively used in conjunction with the supply of electric power.

That is, the present invention utilizes the following advantages by using a rotary engine as a power plant instead of a conventional reciprocating engine.

■Comparing a rotary engine with a reciprocating engine, the noise level generated by the rotary engine is about 5 dB lower at the normal operating speed of around 3000 rpm, as shown in Figure 2, at the same output scale.

■Also, as shown in Figure 3, the vibration level is about 10 dB lower in the rotary engine than in the reciprocating engine in terms of vertical acceleration.

(2) Furthermore, when the engine shaft torque is the same, NOx in the exhaust gas is about 175 in a rotary engine compared to a reciprocating engine, as shown in FIG. In this way, the rotary engine not only has the excellent feature of low pollution, but also can be made very compact in size compared to the reciprocating engine, with a volume ratio of 172 or less.

■However, when using gasoline fuel, rotary engines are not as fuel efficient as reciprocating engines. For this reason, the rotary engine used in the present invention is a gas rotary engine that uses fuel such as 1, PG, or city gas, which is cheaper than gasoline.

■Furthermore, rotary engines do not require dirty oil to build up like in reciprocating engines, so rotary engines do not require oil changes and only need to be refilled.Also, since they use gas as fuel, there is no dirt on the spark plugs. It can be operated continuously for more than one year.

■Furthermore, since gas rotary engines have a higher exhaust gas temperature than reciprocating engines, exhaust heat can be recovered not only as hot water but also as steam. Therefore, if the steam is used in an absorption refrigerator or the like, the efficiency of the absorption refrigerator will be improved, and the efficiency of the entire system will be improved.

Although the gas rotary engine has such excellent characteristics, it has a characteristic that it is less efficient in converting input energy into motive energy than a reciprocating engine. Therefore, when a rotary engine is used only as a power unit, it is not very advantageous in terms of energy efficiency. However, when the rotary engine is used as a power device as in the present invention to effectively utilize thermal energy obtained by exhaust heat recovery in addition to generating electricity, the overall energy efficiency is equivalent to that of a conventional reciprocating engine.

Note that conventionally known heat exchange technology may be used to recover and utilize exhaust heat from the power plant.

[Example 1] FIG. 1 shows an example of a combined heat and power supply system according to the present invention.

This system is composed of a gas rotary engine 1, a generator 2, exhaust heat recovery heat exchangers 4 to 7, an exhaust gas muffler 7a, an absorption refrigerator 8, a hot water storage tank 9, and a radiator IO. and all a except radiator 10
The device is housed in one package 15, and the required amount of electricity,
It is possible to use additional packages 15 depending on the amount of heat.

The rotor shaft of a gas rotary engine 1, which uses LPG, city gas, etc. as fuel 1a, is connected to the rotor shaft of a generator 2, and the rotary engine 1 rotates the rotor of the generator 2 to obtain electric power 2b, which is delivered to the package through a cable. 15 is supplied inside and outside. This electric power 2b is used not only for air conditioning, lighting, and other electrical equipment, but also for electrical equipment (fans) in this system.

Exhaust heat recovery from the gas rotary engine 1 and the generator 2 is performed as follows.

An exhaust heat recovery line 3 that recovers exhaust heat using circulating water is connected to a jacket cooling section 4 of a rotary engine, a lubricating oil heat exchanger 5 (oil cooler), a heat recovery section 6 of an exhaust gas sub-combustion chamber (thermal reactor), The exhaust gas heat exchanger 7 and the absorption refrigerator 8 and hot water storage [9] placed outside the package 15 are connected in series in this order, and the exhaust heat recovery line 3 coming out of the hot water storage tank 9 is connected to the expansion tank 13. It is connected to the jacket cooling section 4 of the rotary engine via a circulation pump 14 to form a circulation loop.

In other words, the water in the heat recovery line 3 is sequentially heated to a high temperature by the circulation pump 14 from the jacket section through each heat exchanger, and is sent to the absorption refrigerator 8 in the form of high-temperature water or steam, where it is cooled by the radiator 10 described later. Using the cooled water 10c as a cold heat source, cold water 8a for air conditioning at 7° C. is generated. The hot water from the exhaust heat recovery line 3 that comes out of the absorption chiller 8 is then transferred to hot water storage N1.
3, heat exchanged with the water in the hot water tank 9, and the water in the hot water tank 9
The water temperature inside the tank is increased and hot water is supplied 9b. The hot water in the hot water storage tank is supplied as needed, and supplementary water is supplied in return. Heat is removed from the hot water in the exhaust heat recovery line 3 in the absorption refrigerator 8 and the hot water storage tank 9, and the temperature decreases, leading to the expansion tank 13 and the circulation pump! 4 to cool the engine jacket and lubricating oil.

In addition, when the temperature of the exhaust heat recovery hot water increases from low to high temperature, the expansion tank 13 provided in the exhaust heat recovery line 3
This is to prevent the internal pressure of the piping line from increasing due to the expansion of the water volume.

When the absorption chiller 8 is not operated or hot water is not consumed and hot water is not supplied, the temperature of the circulating water in the exhaust heat recovery line 3 and the water temperature in the hot water storage tank 9 will rise abnormally, causing engine jacket cooling and lubricating oil to rise. It may interfere with the cooling of the The bypass lines 11a, 1lb, and 11c are provided as switching routes at that time, and when the absorption chiller 8 is stopped or the temperature of the water in the hot water tank 9 reaches a predetermined temperature, the three-way valve 12a is switched on. , 12b, 12
c is switched to cut off the supply of exhaust heat recovery hot water to the absorption chiller 8 or the exhaust heat recovery line 3 in the hot water storage tank 9, and the circulating water is sent to the radiator via the bypass lines Ila, Ilb, and llc to radiate heat and circulate. let Heat radiated hot air 10b
can be used for heating, etc. When the radiator 10 is installed outside the package, it is operated using the electric power obtained from the power generation a2.

Furthermore, the radiator 10 may be incorporated inside the package 15 as long as it is within the allowable range of the package size.

In that case, the cooling fan IQb is gas rotary engine 1
It can be directly connected to the rotating shaft or driven by a belt.

Furthermore, since the heat dissipated from the gas rotary engine 1 and the generator 2 causes a temperature rise inside the package 15, outside air is sucked in by a cooling fan 2a directly connected to the generator rotating shaft, and the inside of the package 15 is cooled and warmed. The air is discharged out of the package from the exhaust fine 17a and used for heating, etc. as necessary.The outside air intake port 16 and the hot air exhaust port 17 are provided with silencers 16a.

17c is effective in reducing noise.

This system uses an absorption refrigerator 8 and a hot water storage tank 9 to utilize waste heat, and each can be used singly or simultaneously with a three-way valve.

That is, when using the absorption chiller 8 and hot water storage Ni 9 at the same time, a three-way valve is used so that hot water circulates through both, and when using either one, the inlet side of the exhaust heat recovery line 3 that is supplied to each is used. Bypass line lla, I required in
Operate the three-way valve so that hot water flows into the lb.

In addition to this embodiment, the exhaust heat recovery and utilization equipment may be an absorption refrigerator, a hot water storage tank, or other single or multiple combinations.The exhaust heat recovery unit may also be an engine jacket exhaust heat lubricating oil heat exchanger, a thermal reactor exhaust gas exchanger, etc. Instead of using all of the exhaust gas, it may be possible to recover only the portion with a large exhaust gas calorific value.

[Effect of the invention] According to the invention, low noise, low vibration, and low N in exhaust gas can be achieved.
LP is a rotary engine with a characteristic of low oxygen content.
G. A combined heat and power generation system that operates using city gas, etc. as fuel, generates electric power by running a generator, and utilizes waste heat effectively, resulting in low pollution and continuous operation over long periods of time. can do.

Additionally, since rotary engines can be much smaller than conventional reciprocating engines, they are also advantageous in terms of space saving, as the generator, heat exchanger, etc. can be installed in one compact package.

[Brief explanation of the drawing]

FIG. 1 shows an example of a system flow of a cogeneration package using a gas rotary engine according to the present invention. Figure 2 compares the sound emitted from the engine bodies of rotary engines and reciprocating engines at different engine speeds. Figure 3 compares the vertical vibrations of a rotary engine and a reciprocating engine at different engine speeds. FIG. 4 compares NOx in the exhaust gas of a rotary engine and a reciprocating engine for each air-fuel ratio with the same shaft torque. 1.-gas rotary engine, l a ”-fuel, 2
... Generator, 2a, 2b = cooling fan, 3.-Exhaust heat recovery line, 4.. Engine jacket cooling section, 5.
... Lubricating oil heat exchanger, 6.-Thermal reactor heat recovery section, 7.. Exhaust gas heat exchanger, 7 a-Exhaust gas muffler,
7b-Exhaust gas, 8.-Absorption refrigerator, 8a-Cold water, 9.
-Hot water storage tank, 9a... Water supply, 9b-... Hot water supply, 10-...
Radiator, 10a-Outside air intake, 10b-Hot air, l0
c-cooling water, 10d-cooling water circulation pump, 10e-cooling fan, Ila, llb, llc... bypass line, +2a, 12b, 12c - three-way valve, l 3-...
Expansion tank, 14...Circulation pump, 15-Package, 16...Outside air intake port, +6a-Suction silencer, 17
...Exhaust port, 17a-...Exhaust fan, 17b-...
Warm air, 17c-exhaust silencer.

Claims (1)

[Claims] 1. A rotary engine that is operated using LPG or city gas as fuel, a generator directly connected to the rotary engine, a heat exchanger that recovers the exhaust heat of the rotary engine, and an exhaust heat recovery line are housed in a package. A combined heat and power generation system using a gas rotary engine, characterized in that it is configured to recover and utilize exhaust heat in addition to supplying electricity.