JP2003269790A - Hot water supply system using waste heat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water supply system using waste heat characterized in securing safety from possible damage of a cooling water passage including a heat feed pipe and improving a heat recovery efficiency at a suppressed cost. <P>SOLUTION: The pressure in the cooling water passage is made different from the pressure in a hot water storage tank 7 and a cooling water storage tank 12 having a water level sensor 13 is provided on the cooling water passage. When there is some damage occurring in the cooling water passage including the heat feed pipe 3, the amount of the cooling water in the cooling water passage is changed due to the leakage from the damage part and the level of the cooling water stored in the storage tank 12 is changed. The damage of the cooling water passage is thus detected by detecting the change in the water level by the water level sensor 13 so as to urgently stop the hot water supply system using the waste heat and raise an alarm. This constitution secures the safety and allows the usage of a single pipe of high heat transmission efficiency as the heat feed pipe 3 at low cost. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply system using exhaust heat for recovering heat from cooling water for cooling an internal combustion engine.

[0002]

2. Description of the Related Art In conventional hot water supply systems using exhaust heat,
A water heat exchanger is provided on a cooling water passage of the internal combustion engine, a hot water supply tank is provided from a water supply pipe, and cooling water of the internal combustion engine is circulated to a primary side of the water heat exchanger by a cooling water pump, The water stored in the hot water supply tank was circulated to the secondary side of the water heat exchanger by a circulation pump to recover heat, and hot water was generated to supply hot water.

In addition to this, as a method of recovering heat from the cooling water of the internal combustion engine and supplying hot water, a circulation pump for circulating the water stored in the water heat exchanger and the hot water supply tank Without using the cooling water passage as a heat supply pipe in the hot water supply tank, the cooling water is circulated to the heat supply pipe by the cooling water pump to recover heat to the water stored in the hot water supply tank. Was being done.

In the system in which the heat supply pipe is provided in the hot water supply tank to recover heat, it is cheaper to use a single pipe as the heat supply pipe, and the hot water supply is provided on the front and back of the heat supply pipe. Since the water stored in the tank and the cooling water come into direct contact with each other, there was no loss in heat transfer and the heat recovery efficiency was good, but in the unlikely event that the heat supply pipe is damaged, the hot water supply Since the cooling water of the internal combustion engine is mixed into the water stored in the tank, there is a risk that hot water will be supplied as it is,
Although expensive, a double pipe was used for this heat supply pipe to prevent contamination with water stored in the hot water supply tank to ensure safety.

[0005]

However, the performance of the hot water supply system utilizing exhaust heat depends on how much exhaust heat from the cooling water or the like can be collected and exhausted. In the countermeasure, the outer pipe of the heat supply pipe and the inner pipe are provided between the cooling water for supplying heat and the water stored in the hot water supply tank.
The water stored in the hot water supply tank exists in contact with the outer circumference of the outer pipe, and since the cooling water flows in contact with the inner pipe, the heat recovery efficiency from the cooling water is higher than that of the single pipe. Originally, it became low, and moreover, it depended largely on the heat transfer coefficient between the outer pipe and the inner pipe of the heat supply pipe.

Therefore, ensuring the safety is, of course, an indispensable condition, but further suppressing the cost
It has been required to improve the heat recovery efficiency.

Therefore, an object of the present invention is to ensure the safety against damage of the cooling water passage including the heat supply pipe in the unlikely event, reduce the cost and improve the heat recovery efficiency. To provide a hot water supply system.

[0008]

According to a first aspect of the present invention, cooling water for an internal combustion engine is circulated by a cooling water pump,
In the waste heat utilization hot water supply system that recovers heat from this cooling water to the hot water supply tank, the pressure in the cooling water passage through which the cooling water flows and the pressure in the hot water supply tank are set to different pressures, and on the cooling water passage, It is characterized in that a storage portion provided with a water level sensor for storing the cooling water is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided detection means for detecting breakage of the cooling water channel based on a position signal of the water level detected by the water level sensor. It is characterized in that it is provided with an informing means for informing.

According to a third aspect of the present invention, in the first or second aspect, the detection means for detecting the damage of the cooling water channel detected by the water level sensor is provided after a predetermined time from the start of operation of the cooling water pump. It is characterized in that it is performed more.

The invention according to claim 4 is the invention according to claims 1 to 3.
In any one of the above items, a cooling water passage through which the cooling water circulates is disposed inside the hot water supply tank, and the cooling water is circulated by the cooling water pump.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

First, in FIG. 1, the water pressure in the cooling water passage and the pressure in the hot water supply tank 7 according to the present invention are set to different pressures,
It is the figure which showed the outline of the waste heat utilization hot water supply system which provided the heat supply pipe in the hot water supply tank and provided the storage tank which has a water level sensor on the cooling water channel.

Explaining the structure of this hot water supply system 100 using exhaust heat, reference numeral 1 is an internal combustion engine that is performing power generation, and 2 is a cooling water pump that circulates the cooling water of the internal combustion engine.

On the cooling water passage in which the cooling water circulates, a three-way valve 4 for switching the distribution destination, a heat supply pipe 3 for supplying heat to the hot water supply tank 7, and the temperature of the cooling water circulating in the cooling water passage. Storage tank 12 having a temperature sensor 10 for detecting the temperature and a water level sensor 13 for detecting the water level of the stored cooling water
And a radiator 5 for radiating the heat that has not been completely recovered in the hot water supply tank 7 by the heat supply pipe 3, and a blower 6 for blowing air to the radiator 5 and the internal combustion engine 1, the cooling water pump 2, and the blower 6 are controlled, and a control unit 11 for detecting the temperature signal of the temperature sensor 10 and the contact signal of the water level sensor 13 is provided, and the hot water supply tank 7 is provided. Is provided with a water supply pipe 8 which is opened in the vicinity of the bottom of the inside and supplies the stored water, and a hot water supply pipe 9 which draws water from the upper part of the stored water and supplies the hot water.

The storage tank 12 provided with the water level sensor 13 provided on the cooling water passage will be described in detail. As shown in FIG.
Is a container formed by resin molding or sheet metal assembly, one end of which is opened near the inner bottom surface and the other end of which is connected to the cooling water passage of the internal combustion engine 1, and the one end of which is open to the atmosphere. And the other end is open-connected to the top surface of the storage tank 12.
A secondary pipe 15 is provided, and the surplus portion of the cooling water circulating in the cooling water passage is stored in the storage tank 12 freely in and out. Includes a reed switch 18a, 18b, a pipe 19 having stoppers 20 at the upper end and the lower end, and a float 16 having a permanent magnet 17 movable up and down on the outer circumference of the pipe 19. A water level sensor 13 composed of and is provided.

The contacts of the reed switches 18a and 18b are sent as contact signals to the control unit 11 through the wiring 21, and by confirming whether these contact signals are on or off, the inside of the storage tank 12 is checked. The control unit 11 can detect the position of the water level.

Further, the means for detecting these contact signals, which is built in the control section 11, is activated from the time when the cooling water pump 2 starts its operation and a certain period of time elapses.

At the start of operation of the cooling water pump 2,
Since the water level of the cooling water stored in the storage tank 12 may temporarily change due to the circulation of the cooling water stopped in the cooling water passage, the control unit 11 This is to avoid detecting that the above is an abnormality on the cooling water passage.

The detection of the water level of the cooling water stored in the storage tank 12 by the water level sensor 13 will be described. For example, when there is no abnormality on the cooling water passage and the cooling water is circulating. The position of the water surface of the cooling water stored in the storage tank 12 is
Since the float 16 is separated from both of the reed switches 18a and 18b at the position of a located in the middle of, the contact signals of both of the reed switches 18a and 18b are turned off, and the control unit 11 receiving this contact signal Then, since the water level of the cooling water is a normal water level, it can be determined that there is no damage on the cooling water passage.

If the heat supply pipe 3 is damaged, the pressure in the hot water supply tank 7 is different from the pressure in the cooling water passage as described above. When the pressure in the hot water supply tank 7 is set to be higher than the pressure in the cooling water passage, the water stored in the hot water supply tank 7 leaks from the heat supply pipe 3 into the cooling water passage, The total amount of the cooling water circulating inside increases.

As a result, the primary pipe 14 is drawn from the cooling water passage.
And the excess amount of the cooling water flows into the storage tank 12 and the air corresponding to the excess amount of the cooling water flowing from the secondary pipe 15 into the storage tank 12 through the cooling water passage is discharged. Then, the water surface of the cooling water stored in the storage tank 12 rises, so that the float 16 of the water level sensor 13 also rises according to this water level.

When the float 16 reaches the position b above the water level sensor 13, the reed switch 18a.
Is turned on by the magnetic field of the permanent magnet 17 built in the float 16, and this contact signal is transmitted through the wiring 21.
It is transmitted to the control unit 11.

Upon receipt of this contact signal, the control unit 11 detects that there is an ON contact signal from the reed switch 18a and detects that the cooling water level in the storage tank 12 is abnormal. Then, it is determined that the heat supply pipe 3 is damaged, and the exhaust heat utilization hot water supply system 100 is stopped urgently.

In this case, the hot water supply system 10 using this exhaust heat
The reason why 0 is stopped urgently is that the cooling water that is cooling the internal combustion engine 1 is an aqueous solution mixed with an antifreeze liquid or the like to prevent freezing in winter, so the heat supply pipe 3 is damaged and hot water is supplied. When the water stored in the tank 7 is mixed with the cooling water, the amount of the cooling water increases, the cooling water runs out, and the internal combustion engine 1 does not overheat and fail. It is intended to prevent the cooling water aqueous solution from being diluted and having the effect of preventing freezing from being lowered.

When the cooling water channel other than the heat supply pipe 3 is damaged, the cooling water flows out of the cooling water channel from the damaged portion of the cooling water channel and circulates in the cooling water channel. Since the total amount of the cooling water to be reduced decreases, the cooling water stored in the storage tank 12 flowing through the primary pipe 14 flows out into the cooling water passage and out of the storage tank 12. Atmosphere corresponding to the amount of the cooling water is sucked in from the secondary pipe 15, and the water level of the cooling water stored in the storage tank 12 is lowered, whereby the water level sensor 1
The float 16 of 3 also descends according to this water level.

When the float 16 reaches the position c below the water level sensor 13, the reed switch 18b.
Is turned on by the magnetic field of the permanent magnet 17 built in the float 16, and this contact signal is transmitted through the wiring 21.
It is transmitted to the control unit 11.

Upon receipt of this contact signal, the control unit 11 detects that there is an ON contact signal from the reed switch 18b, and detects that the water level of the cooling water in the storage tank 12 is abnormal. Then, it is determined that the cooling water channel other than the heat supply pipe 3 is damaged, and the exhaust heat utilization hot water supply system 100 is stopped urgently.

The reason for urgently stopping the hot water supply system 100 using exhaust heat at this time is to prevent the internal combustion engine 1 from overheating and failing due to the decrease in the cooling water.

In this way, when the pressure in the hot water supply tank 7 is set higher than the pressure in the cooling water passage, when the heat supply pipe 3 on the cooling water passage is damaged, The stored water flows into the cooling water passage, the cooling water flows into the storage tank 12, the surface of the cooling water stored in the storage tank 12 rises, and the water other than the heat supply pipe 3 When damage occurs on the cooling water passage, the cooling water flows out of the cooling water passage, the cooling water stored in the storage tank 12 flows out into the cooling water passage, and Since the surface of the stored cooling water descends,
By detecting the water level of the cooling water stored in the storage tank 12 by the water level sensor 13, it is possible to detect that the cooling water passage including the heat supply pipe 3 is damaged.

Further, for example, when the pressure in the hot water supply tank 7 is lower than the pressure in the cooling water passage, the heat supply pipe 3
When damage occurs on the cooling water passages other than the above, the cooling water stored in the storage tank 12 flows out into the cooling water passage, and the water surface of the cooling water descends, similarly to the above.
Even when damage occurs on the heat supply pipe 3, the cooling water in the cooling water passage flows out into the hot water supply tank 7, and the storage tank 12
Since the cooling water stored therein flows out into the cooling water passage and the water surface of the cooling water descends, the pressure in the hot water supply tank 7 may be higher than the pressure in the cooling water passage. It is not possible to determine whether the damaged portion is on the heat supply pipe 3 or on the cooling water passage other than the heat supply pipe 3, but the storage tank 12 including the water level sensor 13 is provided. Is provided on the cooling water passage, and the water level detected by the water level sensor 13 makes it possible to detect the occurrence of damage on the cooling water passage including the heat supply pipe 3.

Further, according to the present invention, a storage tank 1 provided with a water level sensor 13 on the cooling water passage of the internal combustion engine 1.
2 is provided, and the detection means for detecting the water level at the water level sensor 13 to detect the damage on the cooling water channel is provided in the exhaust heat utilizing hot water supply system 100 using the heat supply pipe 3 described in FIG. Not limited to this, the cooling water of the internal combustion engine described as a conventional example is circulated to the primary side of the water heat exchanger, and the water stored in the hot water supply tank is circulated to the secondary side of the water heat exchanger by a circulation pump. It is also possible to detect the breakage on the cooling water passage by providing it to the hot water supply system utilizing exhaust heat for which heat recovery is performed.

In the present embodiment, as an example, as described above, the storage tank 12 is provided with the primary pipe 14 connected to the cooling water passage and the secondary pipe 15 open to the atmosphere. However, not limited to this, an opening is provided near the bottom of the storage tank 12, a pipe is connected from this opening to the cooling water passage, and the cooling water circulating in the cooling water passage is described. The surplus may be stored in the storage tank 12, and the storage tank 12 is used as a tank.
Instead of an independent form, it may be a storage unit for storing the cooling water on the cooling water passage.

A water level sensor 13 provided in the storage tank 12 for detecting the water level of the cooling water is constituted by a plurality of reed switches 18a and 18b and a float 16 having a permanent magnet 17 built therein. However, the present invention is not particularly limited to this, and a plurality of paired electrodes are provided at different height positions in the storage tank 12 to detect the conductivity between each pair of electrodes. The water level of the cooling water stored in the storage tank 12 may be detected.

[0035]

According to the above description, the pressure in the cooling water passage of the internal combustion engine and the pressure in the hot water supply tank of the hot water supply system utilizing exhaust heat are set to different pressures, and the water level sensor is provided on the cooling water passage of the internal combustion engine. By providing a storage tank and detecting the water level with this water level sensor, it is possible to detect damage to the cooling water channel in the unlikely event of an emergency stop of this hot water supply system using exhaust heat,
And because it will be possible to make this notification,
In addition to ensuring safety, there is no need to use expensive double pipes for the heat supply pipes provided in the hot water supply tank, and it is possible to use inexpensive single pipes, so costs are suppressed and heat recovery efficiency is also improved. It becomes possible.

Particularly, by making the pressure in the hot water supply tank higher than the pressure in the cooling water passage, the flow of the cooling water flowing through the cooling water passage into the hot water supply tank when the heat supply pipe is damaged. Since it is also possible to prevent this, a hot water supply system using exhaust heat with even higher safety can be provided.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a waste heat utilization hot water supply system in which a hot water supply pipe is provided in a hot water supply tank, and a storage tank having a water level sensor is provided on a cooling water passage.

FIG. 2 is a schematic diagram showing the storage tank of FIG. 1 and a water level sensor.

[Explanation of symbols]

1 Internal combustion engine 2 cooling water pump 3 heat supply pipes 7 hot water supply tank 11 Control unit 12 Storage tank 13 Water level sensor 14 Primary tube 15 Secondary pipe 16 floats 17 permanent magnet 18a, 18b Reed switch 19 pipes 20 stopper 21 wiring

Claims (4)

[Claims] 1. An exhaust heat utilization hot water supply system in which cooling water of an internal combustion engine is circulated by a cooling water pump to recover heat from the cooling water to a hot water supply tank, the pressure in a cooling water passage through which the cooling water flows, and A hot water supply system using exhaust heat, characterized in that a pressure different from the pressure in the hot water supply tank is provided, and a storage section provided with a water level sensor for storing the cooling water is provided on the cooling water passage. 2. A detection means for detecting breakage of the cooling water channel based on a water level position signal detected by the water level sensor, and further an informing means for informing this. Hot water supply system using waste heat. 3. The method according to claim 1, wherein the means for detecting damage to the cooling water channel detected by the water level sensor is set to be performed after a predetermined time has passed from the start of operation of the cooling water pump. Hot water supply system using waste heat. 4. A cooling water passage through which the cooling water circulates is provided inside the hot water supply tank, and the cooling water is circulated by the cooling water pump. Exhaust heat utilization hot water supply system.