JPH0212546Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an engine-driven heat pump device that uses an internal combustion engine such as a diesel engine or a gas engine as a driving source to operate a refrigerant compressor such as a freon compressor to obtain cold and hot water.

Heat pumps powered by internal combustion engines such as gas engines have higher heating and hot water supply efficiency than electric heat pumps because they can easily recover the exhaust heat from the gas engine and use it for hot water supply and space heating.
It has advantages such as quick start-up of heating, excellent partial load efficiency due to the adoption of gas engine rotation speed control, and high periodic performance coefficient. For this reason, heat pump devices that use engines as their driving source have rapidly spread over the past few years in West Germany and other Western countries, and in Japan, their development is also actively being carried out in various fields. Ta.

Typically, the engine and compressor portions of an engine-driven heat pump device are housed in a machine room or package. Conventional engine-driven heat pump systems use air-cooled manifolds with natural heat dissipation, which often causes temperatures in the machine room and package to rise, causing the electric governor and spark plugs to rise.
There have been cases where this has an adverse effect on the equipment, leading to breakdowns. Particularly on extremely hot summer days when the outdoor temperature is high, the temperature inside the package sometimes exceeds the heat resistance temperature of the engine's electrical components locally. This is because the air-cooled manifold cooler becomes red hot due to exhaust heat from the engine, and the engine electrical components are overheated by this radiant heat. Therefore, in the past, measures were taken to provide forced ventilation by installing fans inside the package cage or machine room, or by installing heat pipes inside the package to dissipate the heat generated by the air cooling manifold outside the package. However, these measures are expensive and do not always give satisfactory results when the outside temperature is extremely high. The present invention aims to solve these problems all at once. In other words, a water-cooled exhaust manifold is used instead of the conventional air-cooled manifold to prevent temperature increases in the machine room or package as much as possible.
Furthermore, in order to effectively utilize the exhaust heat recovered by cooling the water-cooled exhaust manifold, it is absorbed in the engine cooling water circuit that recovers cooling water heat and exhaust heat. Note that when cooling a water-cooled exhaust manifold, there is no problem during high-load operation, but when the cooling or heating load is small, the water-cooled exhaust manifold may be cooled excessively, resulting in condensed water inside the water-cooled exhaust manifold. The problem is that this condensed water flows back into the valves and cylinders.

The present invention has been proposed in view of the above points, and includes cooling the water-cooled exhaust manifold with water flowing in the engine cooling water circuit, and providing a bypass circuit that bypasses the water-cooled exhaust manifold to reduce the load. The bypass circuit is opened when the load is small, and conversely when the load is large, the bypass circuit is closed to cool the water-cooled exhaust manifold and recover exhaust heat from the water-cooled exhaust manifold.

The present invention will be described in detail below based on the example diagrams.
1 is a gas engine, 2 is a compressor driven by the gas engine 1, 3 is a fuel supply path, 4 is an air cleaner attached to the air supply path 5, 6
is a refrigerant circuit, through which fluorocarbon gases such as R-12 and R-22 pass. 7 is a four-way solenoid valve attached to the refrigerant circuit 6, which is used to switch between cooling and heating. 8 is a refrigerant-air heat exchanger, 9 is an expansion valve, 10
is a refrigerant-water heat exchanger that uses the latent heat of vaporization or latent heat of condensation of the refrigerant to produce cold water or hot water. 11 is an engine cooling water heat exchanger; 12 is a water-cooled exhaust manifold of the engine 1 having a water passage 12' formed around it as shown in FIGS. 2 and 3; 13 is an exhaust gas heat exchanger of the engine 1; Engine cooling water heat exchanger 11, water passage 12' in water-cooled exhaust manifold 12, and exhaust gas heat exchanger 13
are arranged (connected) in series to the engine cooling water circuit 16.

14 is a radiator, 15 is a cooling water pump, 17 is a muffler, 18 is an exhaust gas outlet, 19 is an air handling unit, and 20 and 21 are headers.

22 is a bypass circuit provided in the engine cooling water circuit 16 to bypass the water-cooled exhaust manifold 12; 23 is this bypass circuit 2;
A solenoid valve that is switched by an electric signal attached to 2,
24 is a valve inserted between the branch part of the water-cooled exhaust manifold 12 and the bypass circuit 22, and 25 is a valve inserted between the merging part of the water-cooled exhaust manifold 12 and the bypass circuit 22. Numbers 26 to 31 in the figure
is a valve, and 32 is a cold/hot water circuit.

33 is a control that detects the exhaust gas temperature of the engine 1 with a sensor 34, sends a close signal to the electromagnetic valve 23 when the exhaust gas temperature is above a set temperature, and sends an open signal when it is below the set temperature. It is a vessel. Note that this controller 33 may be configured to manually switch the solenoid valve 23.

Next, to explain the operation of the system of the present invention, in the case of heating operation, the compressor 2 compresses the high-temperature, high-pressure fluorocarbon gas that passes through the four-way solenoid valve 7 and reaches the refrigerant-water heat exchanger 10, where the refrigerant is condensed and hot water is produced by using its latent heat. The hot water that has exited the refrigerant-water heat exchanger 10 passes through the header 21 , the cooling water pump 15 , the cooling water heat exchanger 11 , the water-cooled exhaust manifold 12 , the exhaust gas heat exchanger 13 , and the engine cooling water circuit 16 in order. The heated water flows to the air handling unit 19, producing a heating effect. The hot water returned from the air handling unit 19 is guided in a header 20 to a refrigerant-water heat exchanger on one side and to a cooling water pump 15 on the other side. When the heating load is large, the hot water returning from the cooling water pump 15 does not pass through the bypass circuit 22 of the water-cooled exhaust manifold 12 and instead passes through the cooling water heat exchanger 11, the water-cooled exhaust manifold 12, and the exhaust gas heat exchanger 13. pass through sequentially. The water-cooled exhaust manifold 12 merges exhaust gas discharged from each cylinder into one place, and transfers the exhaust gas to an exhaust gas heat exchanger 13 and a muffler 1.
7.

As described above, according to the present invention, when the heating load is large, water in the engine cooling water circuit 16 is passed through the water passage 12' in the water-cooled exhaust manifold 12 to cool the water-cooled exhaust manifold 12 and prevent heat radiation to the atmosphere. do. As a result, overheating inside the package is prevented, allowing operation without adversely affecting electrical components such as the electronic governor and ignition coil. or,
It has also become possible to effectively recover waste heat.

On the other hand, during heating operation with a light load, the cooling water pump 1
5, the engine exhaust gas will be 100
℃ or below, the water-cooled exhaust manifold 12
Condensed water is generated inside the engine, which flows back into the cylinder of engine 1, moistens the plug, and causes troubles such as startup failure. Further, the condensed water flowing back into the cylinder may travel through the piston ring, reach the inside of the crankcase of the engine 1, and mix with the lubricating oil, causing a cloudy phenomenon. If operation continues under such conditions, lubrication failure may occur, and in the worst case, seizing may occur. Therefore, it is absolutely necessary to protect the engine 1 that the water-cooled exhaust manifold 12 is not overcooled during light loads. Therefore, during light load heating, solenoid valve 2
3, open the water-cooled exhaust manifold bypass circuit 2.
The hot water was introduced to 2. In this case, if the entire amount of hot water is introduced into the water-cooled exhaust manifold bypass circuit 22, the manifold will be overheated and there is a risk that the temperature inside the package in which the engine etc. is housed will rise, so the valves 24 and 25 should be operated. , hot water is made to flow simultaneously to the water-cooled exhaust manifold 12. In load control of an engine-driven heat pump system, it is common to first control the rotational speed of the engine 1, and then perform capacity control such as cylinder control of the compressor 2 below a certain load. In this example, when the load factor is 100 to 46%, the rotation speed is controlled from 1750 rpm to 800 rpm with the throttle opening close to fully open, and when the load factor is 46% or less, the engine 1 rotation speed is kept constant at 800 rpm. 2 cylinders are controlled. In this embodiment, the solenoid valve 23 is opened/closed (switched) in accordance with the exhaust gas temperature detected by a sensor. That is, when the exhaust gas temperature is above the set temperature of 150°C, the solenoid valve 23 is closed, and when it is below 150°C, it is opened. Of course, this opening and closing may be done in accordance with the rotational speed of the engine 1 or the number of cylinders of the compressor 2 without any problem. As a result of operating as explained above, hot water flows into the water-cooled exhaust manifold 12 depending on the magnitude of the load.
The air flows through the bypass circuit 22, allowing smooth operation without any problems.

Next, cooling operation will be explained. The high-temperature, high-pressure freon gas that has left the compressor 2 passes through the four-way solenoid valve 7 and reaches the refrigerant-air heat exchanger 8, where the refrigerant is condensed. The condensed refrigerant passes through the expansion valve 9,
The refrigerant reaches the water heat exchanger 10, where the refrigerant evaporates,
The water flowing through the cold/hot water circuit 32 is cooled. During cooling operation, valves 26 and 27 are kept closed. Cooling water loss heat and exhaust gas loss heat from the engine 1 are recovered as hot water in the engine 1's cooling water heat exchanger 11, water-cooled exhaust manifold 12, and exhaust gas heat exchanger 13, and valves 29, 30, and 31 are opened. The heat is radiated in the heat radiator 14. Solenoid valve 23
The opening and closing of is performed according to the exhaust gas temperature of the engine 1, using the same concept as in heating operation.

As mentioned above, in the conventional engine exhaust manifold that assumes natural heat dissipation, the present invention cools the exhaust manifold with water when the load is large and the exhaust heat is high, and when the load is small and the exhaust heat is high. Since the water cooling is stopped when the temperature is low, the heat dissipated from the exhaust manifold will not expose the package housing the heat pump system to high temperatures, and the exhaust manifold will not be overcooled, causing condensed water to build up inside the exhaust manifold. This has the effect of preventing this from flowing back into the engine cylinder and causing trouble.

Next, the present invention provides a bypass circuit 22 that bypasses the water-cooled exhaust manifold 12, and a solenoid valve 23 is installed in this bypass circuit 22.
Since the open or close signal is sent to the water-cooled exhaust manifold 12, water-cooling or water-cooling release of the water-cooled exhaust manifold 12 is reliably performed.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram of a heat pump device embodying the present invention, FIG. 2 is a front view of a water-cooled exhaust manifold, and FIG. 3 is a sectional view taken along line A-A'. 1...Engine, 2...Compressor, 3...
Supply path, 4...Air cleaner, 5...Air supply path, 6...Refrigerant circuit, 7...Four-way solenoid valve, 8...
Refrigerant-air heat exchanger, 9... Expansion valve, 10... Refrigerant-water heat exchanger, 11... Engine cooling water heat exchanger, 12... Water-cooled exhaust manifold, 13... Exhaust gas heat exchanger, 14 ...Radiator, 15...Cooling water pump, 16...Engine cooling water circuit, 17...
...Muffler, 18...Exhaust gas outlet, 19...Air handling unit, 20...Header, 21
... Header, 22 ... Water-cooled exhaust manifold bypass circuit, 23 ... Solenoid valve, 24 ... Valve,
25... Valve, 26... Valve, 27... Valve, 28... Valve, 29... Valve, 30...
Valve, 31...Valve, 32...Cold/hot water circuit,
33...Controller, 34...Sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a heat pump device configured to drive a compressor by an engine and recover cooling water heat and exhaust heat from the engine, a water passage is provided around the water-cooled exhaust manifold of the engine. The engine cooling water circuit is provided with a bypass circuit that connects this water passage to an engine cooling water circuit that recovers the cooling water heat and exhaust heat and also bypasses the water passage (water-cooled exhaust manifold). An engine-driven heat pump device comprising a solenoid valve that is controlled by an electric signal and a controller that sends a switching signal to the solenoid valve in accordance with a predetermined exhaust gas temperature. (2) The engine-driven heat pump device according to claim 1, wherein the controller is of a manual switching type.