JP7594480B2 - Waste heat utilization system - Google Patents

Description

This disclosure relates to a waste heat utilization system.

Technologies are known that reuse the thermal energy contained in exhaust gas, hot water, steam, etc. generated in combustion equipment. For example, Patent Document 1 describes a chip-shaped charcoal manufacturing device that uses part of the exhaust gas discharged from a duct as drying gas when carbonizing wood chips in a furnace and activating them with a mist of spray water and drying them.

JP 2002-088373 A

However, in small and medium-sized boiler turbine generators (BTG) and the like, the cost of installing and maintaining the equipment to recover thermal energy is difficult to justify in relation to the amount of electricity generated, so it has been common to release the waste heat into the atmosphere.

This disclosure was made in consideration of the above problems, and aims to provide a waste heat utilization system that can easily reuse waste heat released into the atmosphere.

To achieve the above object, one embodiment of the waste heat utilization system disclosed herein comprises a building having a roof covering at least the upper part of a combustion facility, a heat receiving pipe arranged in a spiral shape along the side of the roof through which a heat medium flows, and a heat exchanger that extracts heat from the heat medium supplied from the upper end side of the heat receiving pipe and sends the cooled heat medium to the lower end side of the heat receiving pipe.

In a preferred embodiment of the waste heat utilization system, the heat medium vaporizes inside the heat receiving pipe.

A desirable embodiment of the waste heat utilization system includes a windmill that is installed on the upper part of the roof and rotates due to the rising air current inside the building, a generator that generates electricity by the rotation of the windmill, and a circulation pump that is driven by the electricity generated by the generator and supplies the heat medium cooled by the heat exchanger to the lower end side of the heat receiving pipe.

In a preferred embodiment of the waste heat utilization system, the building has a side wall that covers the side of the combustion equipment.

This disclosure provides a waste heat utilization system that can easily reuse waste heat released into the atmosphere.

FIG. 1 is a perspective view that illustrates a schematic diagram of an exhaust heat utilization system according to an embodiment.

The present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to the description of the following embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easy for a person skilled in the art, or those that are substantially the same. Furthermore, the components in the embodiments described below can be omitted, replaced, or modified in various ways without departing from the gist of the present disclosure. In the following embodiments, the components necessary to illustrate the embodiments of the present disclosure will be described, and other components will be omitted.

(Embodiment)
1 is a perspective view showing a waste heat utilization system 1 according to an embodiment. The waste heat utilization system 1 is provided to cover a combustion facility 100 that discharges waste heat Wh to the outside of the facility, and utilizes the waste heat Wh discharged from the combustion facility 100 to the outside of the facility in a heat utilization device. The combustion facility 100 includes, for example, a small- to medium-sized boiler turbine power generation facility that discharges waste heat Wh to the atmosphere, a wood biomass boiler, etc. The heat utilization device includes, for example, a dryer, a chiller, etc. The waste heat utilization system 1 includes a building 10, a heat receiving pipe 20, a high-temperature line Lh, a low-temperature line Ll, a heat exchanger 30, a wind turbine 40, a generator 50, a power transmission line Le, and a circulation pump 60.

The building 10 is provided to cover the combustion equipment 100. The building 10 has a roof section 12, a side wall section 14, and a ventilation section 16. The roof section 12 is provided to cover at least the upper part of the combustion equipment 100. In other words, the roof section 12 is provided in an area where waste heat Wh, such as radiant heat, ascending heat, and radiant heat, emitted from the combustion equipment 100 rises. In this embodiment, the roof section 12 is a quadrangular prism with a rectangular bottom, but in this disclosure, it is not limited to a polygonal pyramid shape, and may be a cone shape, a pyramid shape, a dome shape, a column shape, or the like.

The sidewall portion 14 is provided so as to cover the side of the combustion equipment 100. In the embodiment, the sidewall portion 14 supports the roof portion 12 from below. With the roof portion 12 covering the top of the combustion equipment 100 and the sidewall portion 14 covering the side of the combustion equipment 100, the building 10 can retain the waste heat Wh emitted from the combustion equipment 100 within the building 10. In the present embodiment, the sidewall portion 14 covers the entire side of the building 10, but in the present disclosure, it may cover only a portion, a portion may be openable and closable, or no portion may be provided. In other words, the sidewall portion 14 may be designed appropriately according to the amount of thermal energy of the waste heat Wh to be used in the heat utilization device.

The ventilation section 16 includes an opening provided at the top of the roof section 12. In the ventilation section 16, an ascending air current Ud generated by waste heat Wh emitted from the combustion equipment 100 flows from the inside to the outside of the building 10. A wind turbine 40, which will be described later, is provided in the ventilation section 16.

The heat receiving pipe 20 is provided in a spiral shape along the side of the roof portion 12 of the building 10. The heat receiving pipe 20 has an upper end 22, which is one end in the longitudinal direction and the upper end of the spiral, arranged at a predetermined position on the upper part of the roof portion 12. The heat receiving pipe 20 has a lower end 24, which is the other end in the longitudinal direction and the lower end of the spiral, arranged at a predetermined position on the lower part of the roof portion 12. The heat receiving pipe 20 can be provided inside or outside the roof portion 12 of the building 10. The heat receiving pipe can be built into the roof portion 12 of the building 10. In the embodiment, the heat receiving pipe 20 is provided in a right-handed spiral shape, but in the present disclosure, it may be provided in a left-handed spiral shape. The heat receiving pipe 20 is heated by waste heat Wh discharged from the combustion equipment 100 in the building 10. A heat medium Hm flows inside the heat receiving pipe 20.

The heat medium Hm is a fluid that flows from the lower end 24 to the upper end 22 of the heat receiving pipe 20. As the heat medium Hm flows from the lower end 24 to the upper end 22 of the heat receiving pipe 20, it receives heat from the waste heat Wh emitted from the combustion equipment 100 in the building 10. That is, the temperature of the heat medium Hm increases as it flows from the lower end 24 to the upper end 22 of the heat receiving pipe 20.

The heat medium Hm is preferably, for example, ammonia, which vaporizes inside the heat receiving pipe 20. The heat medium Hm is vaporized inside the heat receiving pipe 20 by the waste heat Wh, which makes it easier to flow inside the heat receiving pipe 20. In the heat receiving pipe 20, the temperature of the heat medium Hm increases toward the upper end 22 (downstream side), so when it vaporizes inside the heat receiving pipe 20, it vaporizes on the upper end 22 side of the heat receiving pipe 20. This reduces the flow resistance of the heat medium Hm on the upper end 22 side, so the heat medium Hm on the lower end 24 side (upstream side) is sucked up to the upper end 22 side, further promoting the flow of the heat medium Hm.

The high-temperature line Lh is a pipe that connects the upper end 22 of the heat receiving pipe 20 to the heat exchanger 30 described below. In the high-temperature line Lh, the heat medium Hm that has been heated by passing through the heat receiving pipe 20 flows from the upper end 22 of the heat receiving pipe 20 toward the heat exchanger 30.

The low-temperature line Ll is a pipe that connects the heat exchanger 30 described below and the lower end 24 of the heat receiving pipe 20. In the low-temperature line Ll, the heat medium Hm cooled in the heat exchanger 30 flows from the heat exchanger 30 toward the lower end 24 of the heat receiving pipe 20.

The heat exchanger 30 is mounted on a heat utilization device including, for example, a dryer, a chiller, etc. The heat exchanger 30 is supplied with a heat medium Hm from the upper end 22 side of the heat receiving pipe 20 through the high temperature line Lh. The heat medium Hm supplied from the high temperature line Lh is in a heated state in the heat receiving pipe 20. The heat exchanger 30 introduces cold air Ac from the outside. The heat exchanger 30 exchanges the heat amount of the sensible heat and latent heat held by the heat medium Hm with the heat amount of the sensible heat held by the cold air Ac. The heat exchanger 30 extracts heat from the heat medium Hm by cooling the heat medium Hm with the cold air Ac. The heat exchanger 30 sends out the cooled heat medium Hm to the lower end 24 side of the heat receiving pipe 20 through the low temperature line Ll. The heat exchanger 30 generates hot air Ah by heating the cold air Ac with the heat medium Hm. In this embodiment, the heat exchanger 30 includes a heat receiving chamber 32 and a heat transfer passage 34.

The heat receiving chamber 32 is connected to the outside of the heat exchanger 30. The heat receiving chamber 32 introduces cold air Ac from the outside. The cold air Ac introduced into the heat receiving chamber 32 is heated by the heat medium Hm passing through the inside of the heat transfer passage 34 provided in the heat receiving chamber 32, and becomes hot air Ah.

The heat transfer passage 34 is provided so as to pass through the inside of the heat receiving chamber 32. The heat medium Hm flows through the inside of the heat transfer passage 34. The upstream end of the heat transfer passage 34 is connected to the high temperature line Lh. The downstream end of the heat transfer passage 34 is connected to the low temperature line Ll. The heat medium Hm passing through the heat transfer passage 34 is cooled by the cold air Ac in the heat receiving chamber 32.

The heat medium Hm passes from the upper end 22 of the heat receiving pipe 20 through the high temperature line Lh, the heat transfer passage 34 of the heat exchanger 30, and the low temperature line Ll, and returns to the lower end 24 of the heat receiving pipe 20. That is, the heat medium Hm circulates through the heat receiving pipe 20, the high temperature line Lh, the heat exchanger 30, and the low temperature line Ll. When the heat medium Hm passes through the heat receiving pipe 20, it is heated by the waste heat Wh emitted from the combustion equipment 100. The heat medium Hm passing through the high temperature line Lh is in a high temperature state. The heat medium Hm passing through the heat transfer passage 34 heats the cold air Ac to generate hot air Ah, and is cooled by the cold air Ac. The heat medium Hm passing through the low temperature line Ll is in a low temperature state.

In the embodiment, the heat exchanger 30 is a shell-tube type in which the heat transfer passage 34 is provided in a serpentine manner inside the heat receiving chamber 32, but this disclosure is not limited to this. In the embodiment, the heat exchanger 30 heats the cold air Ac to hot air Ah using the heat medium Hm, but in the present disclosure, cold water may be heated to hot water, or cold water or hot water may be heated and vaporized to generate hot air Ah.

The windmill 40 is installed in the ventilation section 16 on the upper part of the roof section 12 of the building 10. The windmill 40 includes, for example, a vertical main shaft and a plurality of blades that can rotate integrally with the main shaft around the axis of the main shaft. The windmill 40 rotates by the updraft Ud inside the building 10. More specifically, when the updraft Ud generated by the waste heat Wh discharged from the combustion equipment 100 flows from the inside to the outside of the building 10 through the ventilation section 16, the blades of the windmill 40 receive the updraft Ud in a direction parallel to the main shaft, causing the blades and the main shaft to rotate. That is, the windmill 40 obtains a rotational driving force by the updraft Ud of the waste heat Wh. The main shaft of the windmill 40 is connected to the generator 50, and the rotational driving force is output to the generator 50.

The generator 50 is a well-known generator that includes, for example, a rotor and a stator, and generates an induced current by rotating the rotor relative to the stator due to a rotational driving force input from the outside. The rotor of the generator 50 is connected to the main shaft of the wind turbine 40 directly or indirectly via a transmission, belt, etc. The rotational driving force is transmitted from the main shaft of the wind turbine 40 to the rotor. In other words, the generator 50 generates electricity by the rotation of the wind turbine 40.

The power transmission line Le is a power transmission system that electrically connects the generator 50 and the circulation pump 60 described below. The power transmission line Le supplies the power generated by the generator 50 to the circulation pump 60.

In the embodiment, the circulation pump 60 is provided in the low-temperature line Ll. The circulation pump 60 draws in the heat medium Hm from the upstream side of the low-temperature line Ll and sends it out to the downstream side of the low-temperature line Ll. That is, the circulation pump 60 sends the heat medium Hm cooled by the heat exchanger 30 to the lower end 24 side of the heat receiving pipe 20. The circulation pump 60 is supplied with power from the generator 50 via the power transmission line Le. The circulation pump 60 is driven by the power generated by the generator 50.

As described above, the waste heat utilization system 1 of the embodiment includes a building 10 having a roof portion 12 that covers at least the upper part of the combustion equipment 100, a heat receiving pipe 20 that is arranged in a spiral shape along the side of the roof portion 12 and through which the heat medium Hm flows, and a heat exchanger 30 that extracts heat from the heat medium Hm supplied from the upper end 22 side of the heat receiving pipe 20 and sends the cooled heat medium Hm to the lower end 24 side of the heat receiving pipe 20.

In the waste heat utilization system 1, waste heat Wh generated in the combustion equipment 100 is received by a heat medium Hm flowing inside a heat receiving pipe 20 arranged in the roof section 12. The heated heat medium Hm is cooled in a heat exchanger 30, and then returns to the heat receiving pipe 20 to circulate. The heat exchanger 30 also extracts heat from the heat medium Hm heated in the heat receiving pipe 20 by the waste heat Wh, and can reuse the extracted heat. In addition, the building 10 with the roof section 12 can be installed on an existing combustion equipment 100, so that waste heat Wh that was previously released into the atmosphere from the combustion equipment 100 can be easily reused.

In the waste heat utilization system 1 of the embodiment, the heat medium Hm vaporizes inside the heat receiving pipe 20. When the heat medium Hm vaporizes inside the heat receiving pipe 20 due to the waste heat Wh, the resistance of the heat medium Hm when it flows through the heat receiving pipe 20 is reduced. This can promote the circulation of the heat medium Hm between the heat receiving pipe 20 and the heat exchanger 30. The heat medium Hm in the heat receiving pipe 20 vaporizes at a higher temperature on the downstream upper end 22 side than on the upstream lower end 24 side. This reduces the flow resistance of the heat medium Hm on the upper end 22 side, so the heat medium Hm on the lower end 24 side is sucked up to the upper end 22 side, further promoting the flow of the heat medium Hm.

The waste heat utilization system 1 of the embodiment also includes a windmill 40 that is installed on the upper part of the roof 12 and rotates due to the rising air current Ud inside the building 10, a generator 50 that generates electricity by the rotation of the windmill 40, and a circulation pump 60 that is driven by the electricity generated by the generator 50 and supplies the heat medium Hm cooled by the heat exchanger 30 to the lower end 24 of the heat receiving pipe 20.

Inside the building 10, an updraft Ud is constantly generated by the waste heat Wh released from the combustion equipment 100. In the waste heat utilization system 1, the updraft Ud rotates the windmill 40, and the generator 50 uses the rotational driving force to generate electricity to drive the circulation pump 60. In other words, the updraft Ud can be used to assist the circulation of the heat medium Hm between the heat receiving pipe 20 and the heat exchanger 30, thereby realizing the reuse of the waste heat Wh while reducing the use of external electricity.

In addition, in the waste heat utilization system 1 of the embodiment, the building 10 has a side wall portion 14 that covers the side of the combustion equipment 100. This allows the waste heat Wh emitted from the combustion equipment 100 to be retained within the building 10, thereby reducing waste of the waste heat Wh.

REFERENCE SIGNS LIST 1 waste heat utilization system 10 building 12 roof 14 side wall 16 ventilation section 20 heat receiving pipe 22 upper end 24 lower end 30 heat exchanger 32 heat receiving chamber 34 heat transfer passage 40 windmill 50 generator 60 circulation pump 100 combustion equipment Lh high temperature line Ll low temperature line Le power transmission line Hm heat medium Ac cold air Ah hot air Wh waste heat Ud rising air current

Claims (3)

A building having a roof portion covering at least the upper portion of the combustion equipment;
a heat receiving pipe provided in a spiral shape along a side surface of the roof portion and through which a heat medium flows;
a heat exchanger that extracts heat from the heat medium fed from an upper end side of the heat receiving pipe and sends the cooled heat medium to a lower end side of the heat receiving pipe;
A windmill provided on an upper portion of the roof portion and rotated by an updraft inside the building;
A generator that generates electricity by rotation of the wind turbine;
a circulation pump that is driven by the electric power generated by the generator and that supplies the heat medium cooled by the heat exchanger to a lower end side of the heat receiving pipe;
A waste heat utilization system. The heat medium is vaporized inside the heat receiving pipe.
The waste heat utilization system according to claim 1 . The building has a side wall portion covering a side of the combustion equipment.
The waste heat utilization system according to claim 1 or 2 .

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