JPH0768891B2 - Cogeneration system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system in which exhaust heat of an engine for driving a generator can be effectively used in an absorption refrigerator or the like.

[0002]

2. Description of the Related Art In a cogeneration system, it is well known to use an exhaust heat from an engine to operate an absorption refrigerator. However, since the exhaust heat emitted from the engine varies greatly depending on the load, the conventional system of this type has a large amount of exhaust heat energy, so that the rate at which excess energy is wasted is increased, or conversely, the exhaust heat energy is There is a problem that the absorption refrigerating machine cannot be operated sufficiently due to insufficient supply, which makes it difficult to properly operate the system and lowers the overall thermal efficiency of the system.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and an object thereof is to always ensure proper operation of the system even if the amount of exhaust heat energy fluctuates.

[0004]

In order to achieve the above object, according to the present invention, a forward cooling water passage from the engine to the absorption refrigerator is provided between the exhaust port of the engine and the three-way catalyst. The exhaust gas cooler, the exhaust gas heat exchanger provided between the three-way catalyst and the exhaust silencer, and the heater that is appropriately powered by the control device are passed in this order, and the absorption type is controlled by the electric control means. A first switching valve that appropriately bypasses between the hot water inlet and the hot water outlet of the refrigerator is provided,
In the return cooling water path from the absorption chiller to the engine, a second switching valve that allows the cooling water to pass through a heat exchanger for external heat load when the cooling water temperature is equal to or higher than a set value, and the cooling water A third switching valve that allows cooling water to pass through a heat exchanger for heat radiation when the temperature has not dropped to a temperature suitable for cooling the engine is sequentially provided.

[0005]

The thermal energy of the exhaust gas emitted from the engine is sufficiently given to the cooling water by the exhaust gas cooler and the exhaust gas heat exchanger provided in two stages, and the heater is activated when the exhaust heat energy is insufficient. By doing so, the cooling water is heated to the required temperature. When it is not necessary to send the heated cooling water to the absorption refrigerator, the first switching valve can bypass the cooling water.

Further, when the temperature of the cooling water in the return path is still high, the second switching valve causes the cooling water to pass through the heat exchanger for the external heat load, and the excess energy in the external heat load is sent for use. And can store heat. Only when the temperature of the cooling water is still high, the cooling water is passed through the heat radiating heat exchanger by the third switching valve to lower the temperature of the cooling water and cool the engine. As a result, the utilization rate of the exhaust heat energy becomes high, the absorption refrigerator can be operated even when the exhaust heat energy is small, and the cooling of the engine is not hindered.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment shown in the drawings will be described below. In the figure, 1 is a cogeneration system including a generator 2 and an engine 3 for driving the generator, and 4 is a refrigerating apparatus including a hot water-fired absorption type refrigerator 5. The engine 3 is operated by a fuel 6 such as propane, and an exhaust gas cooler 13, a three-way catalyst 14, an exhaust gas heat exchanger 15 and an exhaust silencer 16 are provided in an exhaust passage 12 extending from an exhaust port 11 of the engine 3. They are provided in this order. Reference numeral 21 is a forward cooling water channel from the cooling water outlet 22 of the engine 3 to the hot water inlet 23 of the absorption refrigerator 5, and 24 is a return cooling passage from the hot water outlet 25 of the absorption refrigerator 5 to the cooling water inlet 26 of the engine 3. It is a waterway.

The cooling water passage 21 is adapted to exchange heat between the exhaust gas and the cooling water through the exhaust gas cooler 13 and the exhaust gas heat exchanger 15, respectively.
It reaches the absorption refrigerator 5 through the 1 and the three-way valve 32. The heater 31 is controlled by the control device 34 via the relay 33, and the three-way valve 32 is electrically operated and is also controlled by the control device 34. The three-way valve 32 switches the cooling water path to absorb the water. The first switching valve appropriately bypasses between the hot water inlet 23 and the hot water outlet 25 of the rotary refrigerator 5.

On the other hand, the cooling water passage 24 has three-way valves 35 and 3
6, a pump 37, and a constant flow valve 38 are provided in this order. The three-way valves 35 and 36 are of the thermostat type that automatically operate according to the temperature of the cooling water flowing through the cooling water passage 24, and the three-way valve 35 on the upstream side has a temperature of the cooling water equal to or higher than a preset value. In this case, the second switching valve allows the cooling water to pass through the heat exchanger 39 for external heat load. The three-way valve 36 on the downstream side is a third switching valve that allows the radiator 40 for heat radiation to pass through the cooling water when the temperature of the cooling water has not dropped to a temperature suitable for cooling the engine 3.

The refrigeration system 4 is an electric three-way valve 4 for proportional control.
5, a cooling tower 46 and the like are provided, and heat is exchanged by, for example, a cooling load absorbing device 47 to operate a cooling device (not shown). 48 is a cistern. The heat exchanger 39 is
The thermal energy obtained from the cooling water is stored in a hot water storage tank 49 which is an external heat load device, for example. 50 is a power load of the generator 2.

The embodiment is constructed as described above and operates as follows. The cooling water flowing out from the cooling water outlet 22 of the engine 3 into the water passage 21 first undergoes heat exchange in the exhaust gas cooler 13 and further heat exchange in the exhaust gas heat exchanger 15 to sufficiently absorb the thermal energy of the exhaust gas, It becomes a high temperature and is sent to the absorption refrigerator 5. When the recovery amount of the thermal energy from the exhaust gas and the engine cooling water is insufficient, the controller 34 operates the heater 31 to heat the cooling water to a predetermined temperature. Therefore, the absorption refrigerating machine 5 does not run short of the thermal energy provided, and can operate reliably. When it is not necessary to operate the absorption refrigerator 5, the control device 34 causes the three-way valve 32 to operate.
Is switched to bypass the cooling water directly to the cooling water passage 24 side.

On the other hand, the temperature of the cooling water discharged from the hot water outlet 25 of the absorption refrigerator 5 or the temperature of the cooling water bypassed from the cooling water passage 21 to the cooling water passage 24 without passing through the absorption refrigerator 5 is higher than the set value. The three-way valve 35 is automatically actuated by the action of a thermostat if it still has sufficient heat energy. Therefore, the water passage 24 is switched so that the cooling water passes through the heat exchanger 39, and the thermal energy of the cooling water is stored in the hot water storage tank 49 and used.

In this way, when the cooling water reaches the three-way valve 36 with or without passing through the heat exchanger 39,
If the temperature has not yet fallen to a temperature suitable for cooling the engine 3, the three-way valve 36 automatically operates by the action of a thermostat. For this reason, the water passage 24 is switched so that the cooling water passes through the radiator 40 and is radiated there, and the sufficiently cooled cooling water returns to the engine 3 to cool the engine 3 and then from the cooling water outlet 22 again. It is sent to the cooling water passage 21 and the above-mentioned operation is repeated.

[0014]

As is apparent from the above description, according to the present invention, the exhaust heat energy of exhaust gas emitted from the engine is exchanged between the exhaust gas cooler and the exhaust gas heat exchanger, and the exhaust heat energy is insufficient. Case (when the generator has a low load and there is sufficient power, and the exhaust heat of the engine is insufficient)
A heater is also used to heat the cooling water.Bypassing the cooling water when it is not necessary to send the heated cooling water to the absorption refrigerator, and when the temperature of the return cooling water is higher than a predetermined value, The heat exchanger for heat load passes the cooling water to give excess energy to the external heat load, and when the temperature of the cooling water is still high, the radiator radiates heat to return it to the engine. Therefore, the utilization rate of exhaust heat energy is high, and even when the exhaust heat energy is low, the absorption refrigerator can be operated, and the cooling of the engine is not hindered. It is possible to properly operate the cogeneration system in which the amount of exhaust heat energy fluctuates greatly and to improve the overall thermal efficiency of the system.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

 1 Cogeneration System 2 Generator 3 Engine 5 Hot Water Absorption Absorption Refrigerator 12 Exhaust Channel 13 Exhaust Gas Cooler 15 Exhaust Gas Heat Exchanger 21 Forward Cooling Channel 24 Return Channel Cooling Channel 31 Heater 32 Three-way Valve (First Switching Valve) ) 35 three-way valve (second switching valve) 36 three-way valve (third switching valve) 39 heat exchanger for external heat load 40 radiator for heat dissipation

Claims (1)

[Claims] 1. A cogeneration system configured to circulate cooling water of an engine for driving a generator to an absorption refrigerating machine to operate the absorption refrigerating machine, from the engine to the absorption refrigerating machine. The forward cooling water channel is appropriately controlled by an exhaust gas cooler provided between the exhaust port of the engine and the three-way catalyst, an exhaust gas heat exchanger provided between the three-way catalyst and the exhaust silencer, and a control device. A first switching valve is provided to allow the electric power to pass through the heater in that order, and a first switching valve that is controlled by the electric control unit to appropriately bypass between the hot water inlet and the hot water outlet of the absorption refrigerating machine. The second switching valve that allows the cooling water to pass through the heat exchanger for the external heat load when the cooling water temperature is equal to or higher than the set value, and the cooling water temperature is suitable for cooling the engine. Temperature drops A cogeneration system characterized in that a third switching valve for allowing cooling water to pass through is provided in the heat exchanger for heat dissipation when it is not in order.