JPH0473063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an exhaust heat-driven absorption refrigeration system that recovers exhaust heat from high-temperature exhaust gas from a combustion furnace, boiler, etc. to drive an absorption refrigerator.

[Conventional technology]

Conventionally, a device that recovers exhaust heat from high-temperature exhaust gas to drive an absorption refrigerator has been developed, for example, in Japanese Patent Application Laid-Open No.
It is disclosed in Publication No. 26290. A flow diagram of the structure of this device near the exhaust heat recovery device is shown in FIG. 4.

Here, 1 is a generator, a solution enters and leaves the outside of the heat transfer tube 2 through solution pipes 3 and 4, and high temperature exhaust gas is supplied to the inside of the heat transfer tube 2 through exhaust gas pipes 5 and 6 and passes through. It has come to be that
The exhaust heat of the exhaust gas is applied to the solution through the heat transfer tube 2, and refrigerant vapor is generated. 7 and 8 are dampers that adjust the amount of exhaust gas supplied. A bypass pipe 9 branches from the exhaust gas pipe 5 and reaches the exhaust gas pipe 6, and is provided with a damper 10 for regulating the bypass flow rate.

[Problem that the invention seeks to solve]

However, such conventional devices have the following problems.

First, as a problem during operation, there is the problem of pressure fluctuations associated with damper operation. That is, in order to control the refrigeration capacity, the amount of heating in the generator 1 is adjusted, and this is done by adjusting the exhaust gas flow rate using a damper. At this time, if the damper 7 is controlled alone, large pressure fluctuations will be given to the exhaust gas generation source, so normally the damper 10 is also controlled in conjunction. However, even if the dampers 7 and 10 are interlocked, it is difficult to adjust the interlocking, and a certain amount of pressure fluctuation remains, which may be unacceptable depending on the type of source.

Further, another problem during operation is that the structure of the damper becomes very large.
That is, normally exhaust gas is often at near atmospheric pressure and has a very large specific volume, and in order to avoid pressure loss during the process, the damper must be very large.
Therefore, the surrounding structure also becomes large, and the device becomes large.

Furthermore, since the exhaust gas is directly led to the generator 1, there is a problem in that it takes time and effort to take measures against corrosion and to convert equipment.

Another problem when the engine is stopped is the leakage of exhaust gas from the damper. That is, the dampers 7 and 8 are closed when there is no load or when the damper 10 is stopped.
Open to prevent exhaust gas from flowing into the generator 1. However, the damper has poor shutoff performance due to its structure, and leakage of about 3 to 5% is unavoidable. Due to this leakage, the liquid temperature in the generator 1 may rise to about 150℃, and the pressure will increase accordingly. It could rise and pose a danger.

The present invention solves the above-mentioned problems in conventional systems, prevents the control mechanism from increasing in size without causing large pressure fluctuations to the exhaust gas generation source during capacity control, and facilitates countermeasures against corrosion. Another object of the present invention is to provide an exhaust heat-driven absorption refrigeration system that can prevent increases in temperature and pressure inside the generator due to gas leakage during shutdown.

[Means for solving problems]

The present invention provides an exhaust heat recovery device with a heating tube for recovering exhaust heat of high-temperature exhaust gas, a generator, a condenser,
An absorption refrigerator having an evaporator and an absorber is provided, and the heated side of the heat exchange section of the exhaust heat recovery device and the heating side of the generator are in communication with each other, and filled with a heat transfer fluid and sealed. , an exhaust gas pipe that guides high-temperature exhaust gas to the heating side of the heat exchange section of the exhaust heat recovery device; and a pipe that heats the heat medium fluid on the heated side and guides the heated heat medium fluid to the heating side of the generator. In the apparatus configured to heat the absorption solution and drive the absorption refrigerator, a temperature detector for detecting the load is provided in the cold water pipe of the evaporator, and this load detection causes the temperature of the exhaust heat recovery device to be increased. An exhaust heat-driven absorption refrigeration system comprising: a flow rate adjustment valve that adjusts the flow rate of heat medium fluid supplied to the exhaust heat recovery section; and a control device that communicates the flow rate adjustment valve with the temperature detector. It is.

〔Example〕

Embodiments of the present invention will be described using the drawings.

In FIG. 1, a heating tube 14 as a heat exchange section is provided in the exhaust heat recovery section 11, and high-temperature exhaust gas is supplied from the exhaust gas pipe 5, passes through it, and is discharged into the exhaust gas pipe 6. The generator 12 is provided with a heat transfer tube 2 adapted to heat the absorption solution. 18 is a flow rate control valve;
The control device 33 is actuated by a signal from the temperature detector 19 that detects the cold water outlet temperature as a load detection, and adjusts the flow rate of the refrigerant liquid sprayed from the spray pipe 17 to the heating tube 14 to control the cold water outlet temperature. Refrigeration capacity is now controlled.

27 is a condenser, 28 is an absorber, 29 is an evaporator,
30 and 31 are cooling water pipes, and 32 is a cold water pipe.

To explain the operation, during normal operation, the heating medium liquid is sprayed into the heating tube 14, heated by high temperature exhaust gas, evaporated, and becomes a heating medium gas, which flows through the pipe line 23.
It is supplied to the generator 12 via the. The heat transfer gas entering the generator 12 is cooled by the absorption solution outside the heat transfer tube 2 and condensed to become a heat transfer liquid. The heat medium liquid enters the exhaust heat recovery section 11 through the pipe line 22, and then enters the pump 2.
0, it is dispersed again into the heating tube 14 via the flow rate control valve 18 and the pipe line 16 and circulated. On the other hand, in the generator 12, the absorption solution outside the heat transfer tube 2 is heated and concentrated.

When the chilled water load decreases, the chilled water temperature rises, but this load decrease is detected by the temperature detector 19, and the flow control valve 18 is operated to control the chilled water temperature so that it does not exceed a predetermined setting range, thereby controlling the capacity. . For example, if there is a small chilled water load, the amount of heat transfer fluid supplied is reduced to a very small amount by the flow rate control valve 18, and if the load is eliminated, the flow rate control valve 18 is fully closed to reduce the heat transfer to the heating tube 14. The amount of medium supplied is zero, eliminating heat recovery ability.

That is, to control the refrigeration capacity by controlling the temperature of chilled water, the flow rate of the heat medium fluid supplied is adjusted instead of adjusting the exhaust gas flow rate with a damper.

This embodiment is configured as described above, and the capacity is controlled by adjusting the supply amount of the heat medium liquid. Therefore, when controlling the capacity, it is possible to control the capacity without giving a large pressure fluctuation to the exhaust gas source. Since the fluid is a liquid, the volumetric flow rate is small, and the dampers 7, 8, 1
Since a small flow control valve 18 is used without the need for a large valve such as 0, etc., the structure is simple and the device is small. In addition, since the exhaust gas is not led directly to the generator, but rather the exhaust heat is indirectly recovered via the exhaust heat recovery section 11 and supplied to the generator 12, it is easy to repair or replace the equipment in the event of corrosion. becomes. moreover,
When the refrigerator is stopped, heat medium fluid is not supplied and the heat recovery ability is eliminated, so the heat of the exhaust gas is not transferred to the generator, and there is no risk of the temperature or pressure inside the generator 12 increasing, preventing danger. can do. Note that when the temperature and pressure of the heat medium fluid in the heat recovery section rise abnormally, the heat medium pump 20 is stopped or the valve 18 is closed to eliminate the heat recovery ability and avoid the abnormal rise.

FIG. 2 shows another embodiment in which the heat transfer fluid passes through the heating tube 14 and is heated by the exhaust gas passing outside thereof, becoming a heat transfer gas and passing through the line 23 to the heat transfer tube 2 of the generator 12. It is now being sent to The heat medium liquid condensed in the heat transfer tube 2 is sent to the exhaust heat recovery section 11 by the pump 20 via the flow control valve 18 .

The temperature detector 19 detects the cold water outlet temperature,
In response to this signal and an operation signal from the control device 33, the flow control valve 18 is adjusted, the amount of heat exchange is adjusted, the chilled water temperature is controlled, and the refrigeration capacity is controlled.

When the heat transfer liquid is supplied to the exhaust heat recovery section 11, it may be supplied from either the upper part or the lower part.
Even if the liquid is supplied from the lower part, the liquid becomes gas-liquid two-phase within the heating tube 14 and is supplied to the heat transfer surface. A wick may be provided on the inner surface of the heating tube 14 to suck up the heat medium from the lower part.

In addition, a heat medium tank 34 is provided in the heat medium fluid path, and when the refrigerator is stopped, this tank stores the heat medium fluid and prevents the heat medium fluid from going to the heat recovery section, so that heat recovery when the refrigerator is stopped is performed. You can definitely eliminate it.

In addition, in the event of an abnormality in the refrigerator or the heat recovery device, the valve 35 can be opened to quickly return the heat medium fluid in the heat recovery section to the heat medium tank, thereby eliminating the heat recovery ability.

FIG. 3 shows another embodiment, in which the generator 12 is placed at a higher position than the exhaust heat recovery section 11, and the condensed heat transfer liquid is supplied to the exhaust heat recovery section 11 by gravity. is omitted.

As the cold water temperature, the inlet temperature may be detected as in this example. The above example is for the case of single effect, but it can also be applied to the case of double effect.

Further, although the above description has been made regarding a refrigeration cycle, it can also be applied to a heating cycle. In this case, for example, the hot water temperature is detected as load detection, and the flow rate control valve 18 is adjusted. The heat transfer medium tank 34 may be provided outside the normal path of the heat transfer fluid, and a safety device may be installed to recover the heat transfer fluid from the tank in an emergency.

〔Effect of the invention〕

The present invention provides a temperature detector for detecting a load in a cold water pipe of an evaporator, and a flow rate regulating valve that adjusts the flow rate of heat medium fluid supplied to the exhaust heat recovery section of the exhaust heat recovery device based on the load detection. By including the flow rate control valve and a control device connected to the temperature detector, the sensible heat of the exhaust gas can be recovered to the heating medium in the form of latent heat, and the amount of heat to be recovered can be controlled to prevent excessive heat recovery. The amount of heat exchange can be adjusted with good responsiveness, the controllability of refrigeration capacity has been significantly improved, the exhaust heat recovery mechanism has been simplified and handling has been simplified, and the device is highly safe. It is possible to perform stable operation without giving large pressure fluctuations to the exhaust gas source when controlling the capacity, it is possible to downsize the equipment without the need for large parts such as dampers, and it is resistant to corrosion. It is possible to provide an exhaust heat-driven absorption refrigeration system that is easy to repair and replace, and can prevent danger without causing a rise in temperature or pressure inside the generator when it is stopped. It has a certain effect.

[Brief explanation of the drawing]

1, 2, and 3 are flowcharts of different embodiments of the present invention, and FIG. 4 is a flowchart of the vicinity of a generator in a conventional example. 1... Generator, 2... Heat transfer tube, 3, 4...
...Solution pipe, 5, 6...Exhaust gas pipe, 7,8...Damper, 9...Bypass pipe, 10...Damper, 11...
...Exhaust heat recovery section, 12...Generator, 14...Heating tube, 16...Pipe line, 17...Spray pipe, 1
8...Flow control valve, 19...Temperature detector, 20...
... Pump, 22, 23 ... Pipe line, 27 ... Condenser, 28 ... Absorber, 29 ... Evaporator, 30, 3
1... Cooling water pipe, 32... Cold water pipe, 33... Control device, 34... Heat medium tank, 35... Valve.

Claims (1)

[Claims] 1 Heating tube 1 that recovers waste heat from high-temperature exhaust gas
4, an absorption refrigerator having a generator 12, a condenser 27, an evaporator 29, and an absorber 28. The exhaust heat recovery device 1 is filled with a heat transfer fluid and sealed in a state where the heating side of the generator is in communication with the waste heat recovery device 1.
Exhaust gas pipes 5 and 6 that lead high-temperature exhaust gas to the heating side of the heat exchanger 1, and pipes that heat the heating medium fluid on the heated side and lead the heated heating medium fluid to the heating side of the generator 12. 23, the apparatus is configured to heat an absorption solution and drive the absorption refrigerator,
A temperature detector 19 for detecting the load is provided in the cold water pipe 32 of the evaporator 29, and a flow rate regulating valve 18 adjusts the flow rate of the heat medium fluid supplied to the exhaust heat recovery section of the exhaust heat recovery device 11 based on the load detection. and a control device 33 that connects the flow control valve 18 to the temperature detector 19.