JPH0253692B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an engine-driven cooling/heating/water heating system.
pt.A.No.5 June 1980), in which 1 is a gas engine, 2 is a compressor coupled to the gas engine, and 3 is a condenser. , 4 is an evaporator, 5 is a pressure reducing device, 6 is a refrigerant arrangement, 2, 3, 4, 5,
6 constitutes a heat pump circuit. 1
1 is a fuel supply pipe that supplies gas fuel to the gas engine 1; 14 is an exhaust pipe that discharges combustion exhaust gas from the gas engine 1 to the atmosphere; 23 is an exhaust gas heat exchanger that recovers heat from the combustion exhaust gas into water; 25 is a condenser 3, a gas engine 1, an exhaust gas heat exchanger 23
This is the water piping that supplies water to the area. 32 is gas engine 1
This is a belt that transmits power from the compressor 2 to the compressor 2.

Next, the operation will be explained.

The gas fuel supplied from the fuel supply pipe 11 is mixed with air introduced from the intake pipe (not shown),
It is supplied to the gas engine 1. The mixture ignited by a spark plug (not shown) produces power similar to a conventional internal combustion engine. Power is transmitted to compressor 2 via belt 32. A heat pump composed of a compressor 2, a condenser 3, an evaporator 4, a pressure reducing device 5, and a refrigerant pipe 6 absorbs heat in the evaporator 4 and radiates heat in the condenser 3. Water supplied from the water supply pipe 25 passes through the condenser 3, the gas engine 1, and the exhaust gas heat exchanger 23, and is gradually heated to become hot water. This hot water is used for room heating and hot water supply. On the other hand, the air supplied to the evaporator 4 is discharged to the outside of the system after being radiated by the evaporator 4.

In conventional engine-driven heating/cooling/water heating systems,
Output control is performed using an intake throttle valve commonly used in automobiles and the like. The intake throttle valve controls the output by changing the density of the air-fuel mixture that the engine takes in, but when the engine is under partial load, the suction work increases due to the pressure drop at the throttle valve, which is a factor that reduces thermal efficiency. Engine-driven air-conditioning, heating, and water heating systems also have the disadvantage that the thermal efficiency of the intake throttle valve during partial load is reduced, resulting in a reduction in the product coefficient of the system as a whole.

In order to improve the above-mentioned drawbacks, the present invention performs output control by adjusting the openings of an intake throttle valve and an intake air heating bypass line opening/closing valve. It is an object of the present invention to provide an engine-driven air-conditioning, heating, and hot-water supply system in which the production coefficient of the system as a whole is improved by performing more efficient operation than when output control is performed using only an intake throttle valve.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a gas engine, 2 is a compressor connected to the gas engine, 3 is an outdoor heat exchanger, 4 is an indoor heat exchanger, 5 is a pressure reducing device, and 6 is a refrigerant pipe. 7 is an air filter, 8 is an electric intake throttle valve, 9 is an intake pipe, and 10 is an air-fuel mixing section provided between the air filter 7 and the intake throttle valve 8. 11 is a fuel supply pipe open to the air-fuel mixing section 10, 12 is an electric fuel valve, and 13 is a constant pressure fuel supply device. 14 is an exhaust pipe; 15 is an intake air heating heat exchanger for recovering the heat retained in the exhaust gas into the air-fuel mixture; 16 is an air mixture branching bypass pipe provided between the intake pipe 9 and the intake air heating heat exchanger 15; 17 Reference numeral 18 designates a bypass pipe for air-fuel mixture merging provided between the intake pipe 9 and the intake air heating heat exchanger 15, and 18 a bypass valve provided in the bypass pipe for air-fuel mixture merging to adjust the flow rate of the air-fuel mixture to be heated. 19 is the exhaust pipe 14
An oxygen sensor 20 is provided in the oxygen sensor 19.
This is a fuel valve control device that drives an electric fuel valve 12 according to the output of the fuel valve 12. 21 is a room temperature measurement thermocouple provided in the indoor heat exchanger 4; 22 is a thermocouple 21;
This is an engine output control device that controls engine output by driving an electric intake throttle valve 8 and an electric bypass valve 18 according to the output of the engine. Note that the compressor 2, refrigerant piping 6, outdoor heat exchanger 3, pressure reducing device 5, and indoor heat exchanger 4 form a heat pump. Although not shown, a four-way valve changes the direction in which the refrigerant flows, making it possible to heat and cool the room. 23 is an exhaust gas heat exchanger that warms water using the heat retained in the exhaust gas; 24 is a hot water storage tank that stores hot water heated by the heat exchanger 23; 25 is a water pipe that connects the heat exchanger 23 and the hot water storage tank 24; A water circulation pump is installed in the middle of the water pipe 25, 27 is a water supply valve that adjusts the amount of water supplied to the hot water storage tank, and 28 is a hot water supply valve that adjusts the amount of hot water supplied from the hot water storage tank. Although not shown, the heat exchanger connected to the hot water tank 24 may be an engine cooling water heat exchanger that recovers heat from the heat retained in the engine cooling water, in addition to the exhaust gas heat exchanger 23. A thermocouple 29 measures the temperature of hot water in the hot water storage tank, and its output is input to the engine output control device 22. 30 is a three-way catalyst for exhaust gas purification. 31 indicates an electric signal line.

As for the operation of the system configured in this manner, the compressor 2 driven by the gas engine 1, the indoor heat exchanger 4, the outdoor heat exchanger 3 and the pressure reducing device 5 perform heating and cooling operations. The exhaust gas that has passed through the exhaust pipe 14 is purified of hydrocarbons, carbon monoxide, and nitrogen oxides by the three-way catalyst 30, and then the heat retained in the exhaust gas is given to water by the exhaust gas heat exchanger 23. Water stored in the hot water storage tank 24 by the water supply valve 27 is circulated between the exhaust gas heat exchanger and the water circulation pump 26, and its temperature increases. Boiled water is taken out by a hot water pump 28.

The gas engine 1 is unloaded by a bypass of the refrigerant circuit on the compressor 2 side or by a clutch installed between the shafts of the compressor 2 and the gas engine 1, and then is started by the starter. Unloading is canceled after the engine starts. The output of the gas engine 1 is set by the gas engine output control circuit 22 according to the difference between the set room temperature or hot water temperature and the actual room temperature or hot water temperature. The thermal efficiency of the engine at this time will be explained based on the diagram. FIG. 2 shows the relationship between engine thermal efficiency, torque, intake throttle valve opening, and bypass valve opening at a certain engine speed. The horizontal axis is the torque. The vertical axis is the thermal efficiency. At point A, the intake throttle valve 8 is fully open and the bypass valve 18 is
is the point of complete closure. The one-dot chain line shows the thermal efficiency according to the conventional operation method in which torque control was performed by changing only the opening of the intake throttle valve 8 while keeping the bypass valve 18 fully closed.
As the opening of the intake throttle valve becomes smaller, the weight of the air-fuel mixture sucked into the cylinder decreases, so the torque decreases, and the suction loss increases, so the thermal efficiency also decreases. The solid line shows the thermal efficiency when the intake throttle valve 8 is kept fully open and the opening degree of the intake heating bypass valve 18 is gradually increased.Starting from point A, the torque gradually decreases and the thermal efficiency also decreases accordingly. However, the output was controlled only by the intake throttle valve opening.
The thermal efficiency is higher than the conventional thermal efficiency shown by the dotted chain line. This is because as the intake air temperature rises, the intake pressure increases and the density of the mixture decreases, but the overall pressure of the mixture supplied to the engine is not much higher than the atmospheric pressure because there is a main flow path for the mixture. As a result, suction losses are reduced, air and fuel are better mixed, ignition performance is improved, engine cycle-to-cycle fluctuations and cylinder-to-cylinder non-uniformity are suppressed. Note that if the density of the air-fuel mixture, that is, the weight flow rate, is controlled by the opening degree of the intake throttle valve and the opening degree of the intake heating bypass valve, and the output of the engine is controlled, the air-fuel mixture supplied to the gas engine 1 will inevitably be Since the fuel ratio changes, the fuel valve control device 20 is controlled by the signal from the oxygen sensor 19.
operates the electric fuel valve 12 to maintain a predetermined air-fuel ratio at all times. As a result, the three-way catalyst works effectively to purify carbon monoxide, hydrocarbons, and nitrogen oxides. Further, although not shown, the ignition timing is automatically adjusted at this point, so that thermal efficiency does not decrease due to mismatched ignition timing. If necessary, by restricting the intake throttle valve 8 to point B and then gradually opening the bypass valve 18, it is also possible to operate at the thermal efficiency shown by the broken line starting from point B.

As described above, the present invention includes an air conditioning compressor, a gas engine that drives the compressor, a hot water supply unit that warms water using the heat retained in the engine, and an intake air supply that supplies a mixed gas of fuel gas and air to the gas engine. a pipe, an exhaust pipe that discharges exhaust gas from the gas engine, a first valve that opens and closes the intake pipe, a bypass pipe that branches the intake pipe downstream of the first valve and bypasses the mixed gas; An intake air heating exchanger that heats the mixed gas in the bypass pipe using the exhaust heat of the gas engine, a second valve that opens and closes the bypass pipe, and a small difference between the room temperature or the set temperature of the hot water supply section and the detected temperature. Since the engine-driven air conditioning/heating and hot water supply system is configured with a control unit that controls opening/closing of the first valve opening to a small degree and the second valve opening to a large degree, a significant improvement in thermal efficiency can be achieved. This has the effect of improving the coefficient of performance of the gas engine-driven air-conditioning, heating, and hot-water supply system. especially. When the weight of the air-fuel mixture is small (when the first valve opening is small), increasing the bypass flow rate increases the suction loss improvement effect and improves thermal efficiency.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a gas engine-driven air-conditioning/heating/hot-water supply apparatus in one embodiment of the present invention. FIG. 2 is a characteristic diagram showing the relationship between engine thermal efficiency, torque, intake air heating bypass opening, and intake throttle valve opening at a certain engine speed. FIG. 3 is a configuration diagram of a conventional engine-driven heating and hot water supply device. In the figure, 1 is a gas engine, 2 is a compressor, 3 is an outdoor heat exchanger, 4 is an indoor heat exchanger, 5 is a pressure reducing device, 6
1 is a refrigerant pipe, 7 is an air filter, 8 is an intake throttle valve, 9 is an intake pipe, 10 is an air-fuel mixing section, 11 is a fuel supply pipe, 12 is a fuel valve, 13 is a constant pressure fuel supply device, 14 is an exhaust pipe, 15 is an intake air heating heat exchanger,
16 is a bypass pipe for mixture branching, 17 is a bypass pipe for mixture merging, 18 is a bypass valve, 19 is an oxygen sensor, 20 is a fuel valve control device, 21 is a thermocouple for measuring room temperature, 22 is an engine output control device, 23 is an exhaust gas heat exchanger, 24 is a hot water storage tank, 25 is a water pipe, 26 is a water circulation pump, 27 is a water supply valve, 28 is a hot water supply valve, 29 is a thermocouple for measuring hot water temperature, 30 is a ternary for exhaust gas purification The catalyst, 31 is an electric signal line.

Claims (1)

[Claims] 1. An air conditioning compressor, a gas engine that drives this compressor, a hot water supply unit that warms water using the heat retained in the engine, an intake pipe that supplies a mixture of fuel gas and air to the gas engine, and an intake pipe that supplies exhaust gas from the gas engine. an exhaust pipe for discharging air; a first valve for opening and closing the intake pipe; branching the intake pipe downstream of the first valve;
A bypass pipe that bypasses the mixed gas, an intake air heating heat exchanger that heats the mixed gas in the bypass pipe using the exhaust heat of the gas engine, a second valve that opens and closes the bypass pipe, and a room temperature or hot water supply section. When the difference between the set temperature and the detected temperature is small, the engine-driven air-conditioning/heating/water supply device includes a control unit that controls opening/closing of a first valve opening to a small degree and a second valve opening to a large degree.