Agricultural greenhouse heating system using unused heat from a power-generating wind turbine

Abstract

An agricultural greenhouse heating system is provided that uses unused heat generated by a power-generating wind turbine as a heat source to heat an agricultural greenhouse. [Solution] The system comprises an excess heat recovery means for recovering excess heat generated from a converter 21 and an inverter 22 in electrical equipment 2 installed inside the tower 1 of a power-generating wind turbine, a heat transfer means for transferring the recovered heat to an agricultural greenhouse, and a heat dissipation means for dissipating heat into the agricultural greenhouse and / or the soil inside the greenhouse. When the wind conditions in the farmland are good, heat can be supplied at low cost, making it possible to cultivate high-value-added crops in facilities that can enjoy the heat supply from wind power generation, thereby realizing wind power generation that is in harmony with agriculture and contributes to the healthy development of agriculture.

Description

[Technical Field]

[0001] This invention relates to a system for heating agricultural greenhouses using unused heat generated by wind turbines for power generation as a heat source, and more specifically to a system for heating agricultural greenhouses using excess heat generated by the converters and inverters of wind turbines for power generation, and geothermal heat extracted from holes excavated during the installation of wind turbine foundations. [Background technology]

[0002] The installed capacity of wind power generation in Akita Prefecture, where the applicant resides, was approximately 355,000 kW as of the end of fiscal year 2017, and is expected to increase further due to future offshore wind power generation plans, etc. However, on land, there are few locations with suitable wind conditions remaining near the coast, which has been the main installation location for onshore wind power generation to date. Therefore, it is expected that future onshore wind power generation will shift to inland areas seeking suitable locations with excellent wind conditions, but when suitable sites are agricultural land, restrictions under the Agricultural Land Act become an obstacle, and this shift has not progressed nationwide. In this context, there has been a growing movement in various regions to use agricultural land for generating electricity using renewable energy.

[0003] Against this background, the Agriculture, Mountain and Fishing Villages Renewable Energy Act was enacted with the aim of revitalizing agricultural, mountain and fishing villages and contributing to the diversification of energy sources by taking measures to promote renewable energy power generation in harmony with the healthy development of agriculture, forestry and fisheries in agricultural, mountain and fishing villages. This law requires that efforts to contribute to the healthy development of agriculture be made when installing wind power generation on farmland.

[0004] Meanwhile, in greenhouse horticulture in cold regions, including Akita Prefecture, fuel costs are high in winter, making it an issue to provide low-cost heat during the winter. In response to this issue, the use of geothermal energy has been proposed and research and development is underway (Patent Document 1). However, because heat needs to be extracted from a depth where a constant temperature can be maintained, the cost of equipment and the running costs of heat exchangers are an issue, and this method has not yet become widespread. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-156820 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, when installing wind power generation on agricultural land, efforts are required to contribute to the healthy development of agriculture. The purpose of this invention is to provide an equipment system that will enable the installation of power-generating wind turbines to contribute to the healthy development of agriculture. [Means for solving the problem]

[0007] After much research into achieving the above objectives, the inventor discovered that by utilizing the surplus heat generated by converters, inverters, etc. from the power-generating wind turbines and the geothermal heat extracted from the holes drilled when installing the wind turbine foundations, it would be possible to supply heat to agricultural greenhouses at low cost, thereby realizing a system that would allow the installation of wind power generation to contribute to the development of agriculture. 1. (1) A converter and an inverter of a power-generating wind turbine are installed in a tower, and an excess heat recovery means is provided to recover excess heat generated from the converter and the inverter. (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) A heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system. 2. (1) A means for recovering excess heat generated from (I) a converter and inverter installed in the tower of a power-generating wind turbine, (II) a transformer installed in the tower, (III) a speed increaser, and (IV) friction of bearings, which recovers (I) and recovers one or more of (II) to (IV). (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) A heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system. 3. (1-1) A converter and an inverter of the power-generating wind turbine are installed in the tower, and an excess heat recovery means recovers excess heat generated from the converter and the inverter; (1-2) a geothermal heat recovery means for recovering geothermal heat from a hole excavated when installing a foundation for a power-generating wind turbine; (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) A heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system. 4. (1-1) A means for recovering excess heat that recovers (I) and one or more of (II) to (IV) from excess heat generated by (I) a converter and inverter installed in the tower of a power-generating wind turbine, (II) a transformer installed in the tower, (III) a speed increaser, and (IV) friction of bearings. (1-2) a geothermal heat recovery means for recovering geothermal heat from a hole excavated when installing a foundation for a power-generating wind turbine; (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) A heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system. [Effects of the Invention]

[0008] According to this invention, when the wind conditions in farmland are good, heat can be supplied at low cost, making it possible to cultivate high-value-added crops in facilities that can enjoy heat supply from wind power generation, thereby realizing wind power generation that contributes to the healthy development of agriculture and is in harmony with agriculture. As a result, the introduction of wind power generation on agricultural land will also progress, leading to the creation of a local energy industry. [Brief explanation of the drawings]

[0009] [Figure 1] The device configuration of the agricultural greenhouse heating system of this invention is shown. [Figure 2]The basic structure of a propeller-type wind turbine is shown (A), and the circuit diagram of the electrical equipment 2 is also shown (B). DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0011] 1. Overview of the agricultural greenhouse heating system of this invention Figure 1 shows an example of an agricultural greenhouse heating system of the present invention that uses both surplus heat generated by a converter and inverter and geothermal heat. The surplus heat generated by the converter and inverter in the electrical equipment 2 installed in the tower 1 of a propeller-type wind turbine, and the geothermal heat collected from a hole excavated during the installation of the wind turbine foundation 3, are recovered in a heat transfer medium 31 and supplied to an agricultural greenhouse 41. By using unused surplus heat and geothermal heat, low-cost heat supply can be achieved.

[0012] 2. Utilizing excess heat from power-generating wind turbines (1) The wind turbine of this invention is a wind turbine for generating electricity. Power-generating wind turbines can be of any type, including propeller, Savonius, and Darrieus types. In the case of a propeller-type wind turbine, its basic components consist of rotor blades 11, nacelle 12, tower 1, and foundation 3 (Figure 2). The rotor blades 11 rotate due to the force of the wind, and the rotation speed is increased by a gear step-up gear 13 inside the nacelle 12, turning a generator 14. The generated AC is converted to DC by a converter 21 in the electrical equipment 2, and then converted back to AC by an inverter 22, and then connected to the grid via a transformer 23. Once converted to DC, the passing power can be freely controlled. The energy loss from a power-generating wind turbine before it is connected to the grid is estimated to be around 2.5% of the amount of electricity generated, most of which is energy loss in the converters and inverters, which becomes excess heat. In this invention, the converter and inverter, which are usually installed outside the tower, are installed inside the tower to reduce heat radiation to the outside air. Furthermore, the excess heat generated by the converter and inverter is not dissipated by a heat dissipation fan, but is instead used as a heat source for the agricultural greenhouse. In addition to the converter and inverter, other sources of excess heat in the tower include, for example, the gearbox, friction generated by bearings, and the transformer, and these may all be used as heat sources. In this case, the transformer is installed inside the tower. (2) The means for recovering excess heat in the tower may be a means for recovering heat by laying heat transfer medium pipes around each device such as the converter and inverter, or a means for recovering heat from exhaust heat to the heat transfer medium using a gas / liquid heat exchanger.Furthermore, these means may be combined. For example, in the case of excess heat from the converter and inverter, a heat medium may be passed through a conventional water-cooled path to recover the heat to the heat medium. (3) In the case of a large wind turbine with a generating capacity of 4,000 kW, 2.5% (100 kW) of excess heat is generated, which is equivalent to one-third of the monthly consumption of an average household (300 kWh) in one hour, and this heat can be used in agricultural greenhouses. Furthermore, on the Sea of ​​Japan side of the Tohoku region, winds are stronger in winter and more electricity is generated, so even more excess heat is generated, which can perfectly complement greenhouse horticulture, which requires a heat source in winter.

[0013] 3. Use of geothermal energy Geothermal heat is underground heat that is found anywhere relatively shallow underground (up to about 100 meters underground). To install the wind turbine foundation, an excavation is performed to a depth of about 3 to 10 meters, more preferably 5 to 6 meters. Heat can be extracted from the bottom of this foundation. When installing the wind turbine foundation, deeper holes are also excavated to install foundation piles 4 (Figure 1). Heat can also be extracted from these holes. For example, hollow foundation piles can be used to extract heat from them (Reference 1: "Example of a steel pipe pile-type geothermal heat utilization system http: / / www.geohpaj.org / old_information / doc / nakamura.pdf"). Heat can also be extracted from both. More specifically, as a means of recovering underground heat, a hose-shaped underground heat exchanger 5 (Fig. 1) may be installed horizontally on the bottom surface of the wind turbine foundation to extract heat, or a hose-shaped underground heat exchanger may be installed vertically on a hollow foundation pile to extract heat. By using the holes excavated when installing the wind turbines, there is no need to excavate new holes to collect geothermal heat, making it possible to supply heat at low cost.

[0014] 4. Heat transfer There are no particular restrictions on the means of heat transfer. For example, heat can be transferred using a heat transfer medium. In this case, a heat pump can be used to extract more heat. Furthermore, since geothermal heat is around 10 to 15°C and the exhaust temperature of the transformer is higher, a system can be configured in which the heat transfer medium is preheated using geothermal heat, and then further heated using the surplus heat from the transformer. Furthermore, the system may use a fan to blow excess heat or geothermal heat directly into an agricultural greenhouse. In this case, the fan serves as both the heat recovery means and the heat dissipation means, and the air serves as the heat transfer means.

[0015] 5. Heat dissipation to agricultural greenhouses The agricultural greenhouse may be made of any material, such as resin such as polyvinyl chloride, or glass. The heat dissipation means may heat the air inside the agricultural greenhouse, but since surplus heat from a transformer and geothermal heat are low-temperature heat sources, it is more preferable to lay a heat dissipation pipe underground inside the agricultural greenhouse to directly heat the ground.

[0016] The idea of ​​utilizing unused heat from wind turbines as described above, specifically the idea of ​​using excess heat from inverters, converters, etc. and geothermal heat from the wind turbine foundations for agriculture, is a completely new idea, and this invention is the pioneer of it. [Industrial Applicability]

[0017] This invention is useful for agriculture, as it provides a low-cost heat source for agricultural greenhouses. It is also useful for the wind power industry, as it helps secure locations for wind turbines in areas with suitable wind conditions. [Explanation of symbols]

[0018] 1. Tower 2. Electrical equipment 3 Basics 4 Foundation piles 5 Geothermal heat exchanger 11 rotor blades 12 Nacelle 13 Gearbox 14. Generator 15 Power Lines 21 Inverter 22 Converter 23 Transformer 31 Heat Transfer Medium 41 Agricultural greenhouses

Claims

1. (1) A converter and an inverter of a power-generating wind turbine are installed in the tower, and an excess heat recovery means recovers excess heat generated from the converter and the inverter. (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) a heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system.

2. (1) A surplus heat recovery means for recovering surplus heat generated from (I) a converter and inverter installed in the tower of a power-generating wind turbine, (II) a transformer installed in the tower, (III) a speed increaser, and (IV) friction of bearings, and recovering surplus heat generated from (I) and one or more of the surplus heat generated from (II) to (IV). (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) a heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system.

3. (1-1) A converter and an inverter of a power-generating wind turbine are installed in a tower, and an excess heat recovery means recovers excess heat generated from the converter and the inverter; (1-2) a geothermal heat recovery means for recovering geothermal heat from a hole excavated when installing a foundation for a power-generating wind turbine; (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) a heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system.

4. (1-1) A surplus heat recovery means for recovering surplus heat generated from (I) a converter and inverter installed in the tower of a power-generating wind turbine, (II) a transformer installed in the tower, (III) a speed increaser, and (IV) friction of bearings, and recovering surplus heat generated from (I) and one or more of the surplus heat generated from (II) to (IV). (1-2) a geothermal heat recovery means for recovering geothermal heat from a hole excavated when installing a foundation for a power-generating wind turbine; (2) a heat transfer means for transferring the recovered heat to the agricultural greenhouse; (3) a heat dissipation means for dissipating heat to an agricultural greenhouse and / or the soil in the greenhouse; This is an agricultural greenhouse heating system.

5. The agricultural greenhouse heating system of any one of claims 1 to 4, wherein the excess heat recovery means is a means for recovering heat from waste heat to a heat medium using a gas / liquid heat exchanger, or a means combining this with a means for recovering heat by running heat medium piping to each device such as a converter and an inverter.

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