The present application claims priority to Korean Application No. 10-2018-0157774, filed in Korea on Dec. 10, 2018, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cogeneration system, and more particularly, to a cogeneration system for improving efficiency and stability, reducing harmful substances in exhaust gas, and changing a refrigerant flow according to condensation/evaporation of the refrigerant.

2. Description of the Related Art

The gradual depletion of fossil fuels, which is the most widely used energy source, has led to the interest in alternative energy that can be continuously renewed by using infinite natural energy such as the sun, wind, waves, biological organisms and their waste. Further, most of all, clean energy causing little pollution unlike fossil fuels that have been used before is required. In particular, as the environmental problems such as environmental pollution and climate change conventions became social concerns in the 1990s, the importance of these has become even more important.

Among the alternative energy projects, the power generation project using landfill gas (LFG) is the most applied field of landfill gas energy conversion projects. The composition of landfill gas, which is the raw material of such a system, is mainly composed of 45-60% methane (CH4), 35-40% carbon dioxide (CO2), and trace amounts of N2, O2. Since landfill gas has a heating value of about 4,500 to 5,500 kcal/m3 based on 50% of methane content, it is the most important material of landfill gas recycling project and used as the fuel of gas engine driving.

Gas engines using landfill gas may be classified into a dedicated engine and a dual fuel engine. Since the dual fuel engine uses the existing diesel engine intactly, the retrofit is easy and the flammable limit is wide, so that stable operation can be achieved even with changes in fuel composition. The dedicated engine has an advantage in that only gas is used as fuel, but it has difficulty in operating in a place where gas component is severely changed because the heating value of fuel must be somewhat high and the gas component must be uniform. In order to maximize the fuel conversion efficiency of the engine in the operating range in which combustion stability is ensured, precise control of each component according to the characteristics of the fuel-air mixture is required.

In particular, when the concentration of the gaseous fuel is lean, there is a problem that power generation is difficult due to poor ignition, and in the case of the gas, when the combustion is performed by a natural aspirated engine, there is a limit in improving the output due to the low supply pressure.

In order to solve the shortcomings of the natural aspirated engine, the prior art includes a compressor connected to the shaft of the engine by a belt, so that intake pressure of the engine can be enhanced, and the efficiency of the engine can be improved.

However, when the compressor is connected to the engine by a belt as in the prior art, there is problem of noise and large space occupancy, and there is disadvantage that the compression ratio of the compressor cannot be precisely controlled due to the connection to the shaft of the engine by the belt.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems, and provides a cogeneration system having improved stability while improving the output of an engine.

The present invention further provides a cogeneration system for reducing the volume of a product, and preventing the leakage of a mixed gas, by configuring a gas supply unit for supplying mixed gas and an intake compressor for compressing the gas supply unit mixed gas as a single module.

The present invention further provides a cogeneration system for using a motor-type intake compressor which allows precise compression ratio control and preventing the mixed gas from burning when an electric leakage occurs in an electric line controlling a motor.

The present invention further provides a cogeneration system for disposing a gas supply unit for mixing gas and air in between the motor and the impeller of the intake compressor.

The present invention further provides a cogeneration system for disposing a gas supply unit for mixing gas and air in between the motor and the impeller of the intake compressor, and disposing the motor in the upper stream from which air flows.

In accordance with an aspect of the present invention, a cogeneration system includes: an air intake pipe through which air is introduced, a gas intake pipe into which gas is introduced, a mixed gas intake pipe which is connected to the air intake pipe and the gas intake pipe and supplies a mixed gas of air and gas to an engine, a gas supply unit for mixing the gas supplied from the gas intake pipe with air in the air intake pipe, and an intake compressor for compressing the mixed gas, and the intake compressor includes a motor disposed in the intake pipe, and a compressor impeller which is disposed in the intake pipe, and rotates by the motor to compress the mixed gas.

The gas supply unit is disposed between the motor and the compressor impeller in the intake pipe.

The gas supply unit includes an acceleration unit for reducing a cross-sectional area of the air intake pipe while progressing toward the compressor impeller from the motor, and a spray unit which has a smaller cross-sectional area than the acceleration unit, and is provided with a spray hole connected to the gas intake pipe.

The spray unit is disposed closer to the compressor impeller than the acceleration unit.

The cogeneration system further includes a shaft connecting the motor and the compressor impeller, and the spray unit and the acceleration unit are disposed to surround the shaft.

The compressor impeller includes a first compressor impeller connected to the motor by a shaft, a second compressor impeller, and a clutch for connecting or disconnecting power of the first compressor impeller to the second compressor impeller.

The cogeneration system further includes a cooler for cooling the mixed gas compressed in the intake compressor

In accordance with another aspect of the present invention, a cogeneration system includes an intake pipe having one end which communicates with the outside air and having the other end which is connected to an engine, a gas supply unit disposed in the intake pipe to supply gas into the intake pipe, and an intake compressor for compressing a mixed gas which is a mixture of the air and the gas, wherein the intake compressor includes a motor disposed in the intake pipe; and a compressor impeller which is disposed in the intake pipe, and rotates by the motor to compress the mixed gas, wherein the gas supply unit is positioned between the motor and the compressor impeller.

The motor is disposed upstream of the gas supply unit.

The gas supply unit is disposed between the motor and the compressor impeller in the intake pipe.

The intake pipe includes: a motor accommodating part in which the motor is disposed; a gas supply unit accommodating part in which the gas supply unit is disposed; and an impeller accommodating part in which the compressor impeller is positioned.

The gas supply unit accommodating part is positioned between the motor accommodating part and the impeller accommodating part.

The gas supply unit includes: an acceleration unit for reducing a cross-sectional area of the gas supply unit accommodating part while progressing toward the compressor impeller from the motor; and a spray unit which has a smaller cross-sectional area than the acceleration unit, and is provided with a spray hole connected to the gas intake pipe.

The spray unit is disposed closer to the compressor impeller than the acceleration unit.

The cogeneration system further includes a shaft connecting the motor and the compressor impeller, and the spray unit and the acceleration unit are disposed to surround the shaft.

The compressor impeller includes: a first compressor impeller connected to the motor by a shaft; a second compressor impeller; and a clutch for connecting or disconnecting power of the first compressor impeller to the second compressor impeller.

The cogeneration system further includes a cooler for cooling the mixed gas compressed in the intake compressor, and the cooler is positioned in the intake pipe between the engine and the compressor impeller.

The cogeneration system further includes a generator for generating power by a power of the engine.

The cogeneration system further includes a hot water storage tank for storing heat medium recovering heat generated by the engine.

The first compressor impeller is disposed closer to the motor than the second compressor impeller, and the gas supply unit is positioned between the first compressor impeller and the motor.

