Greenhouse heating system using duct hose provided with exhaust dampers

Abstract

To enable precise temperature control in an agricultural greenhouse, to make uniform heating without temperature gradients possible, and further to make it possible to heat a specific area inside the greenhouse to an arbitrary temperature without using partitions such as curtains.SOLUTION: Multiple exhaust dampers that can be opened and closed are provided in a duct hose, and are opened and closed arbitrarily by electromagnetic valves or the like to make the temperature of the entire greenhouse uniform. A closed-branch duct hose having a closed tip is connected to the exhaust dampers, and heating is performed by surface radiant heat. When an exhaust damper is closed, supply of warm air to the closed-branch duct hose is stopped and radiant heat is not generated, so that temperature control becomes possible by opening and closing the exhaust dampers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a heating system using a combustion-type hot air heater used in greenhouse cultivation. It is a dynamic temperature control system that makes it possible to maintain a uniform temperature throughout the greenhouse or to locally set a desired temperature in a specific area, and it also reduces heating costs, and it can be implemented at the lowest possible cost. [Background technology]

[0002] In greenhouse cultivation, it is common to use heaters to maintain a constant temperature throughout the greenhouse, but in order to grow crops evenly, various measures are taken to systematically control the temperature and ensure an even temperature distribution throughout the greenhouse, and there is a need to minimize the cost-effectiveness of these measures.

[0003] The conventional heating method is to connect multiple vinyl ducts to the heater's air outlet, exhaust hot air from the duct's outlet and circulate it throughout the greenhouse, or heat it by radiant heat from the duct surface.The heater's operation is then controlled to maintain a constant temperature by intermittent operation using a temperature sensor inside the greenhouse.

[0004] Temperature gradients occur inside the greenhouse depending on the orientation of the greenhouse and the location of the heater, so to prevent this, fans must be installed separately to mix the air inside the greenhouse and exhaust the air outside, resulting in additional costs.

[0005] It would be desirable to precisely control the temperature by controlling the amount of fuel supplied to the burner and controlling the combustion temperature, but due to cost, maintenance, etc., such heaters with variable combustion temperatures are not widely used at present. Also, measures to prevent temperature gradients have been taken, such as using curtains as partitions.

[0006] Patent Document 1 uses a burner that controls the amount of fuel injected and thereby controls the combustion temperature of the heater, but no matter how precisely the combustion temperature can be controlled, in order to distribute this warm air throughout the greenhouse and maintain a uniform temperature, it is necessary to adjust the amount of warm air discharged from each duct and take into account the radiant heat from the duct surface, thereby achieving comprehensive temperature control, which Patent Document 1 does not take into account.

[0007] In Patent Document 2, a specific area is divided into individual areas using partitions, etc., and not only is the temperature uniform throughout the area, but the temperature of each area is also dynamically controlled individually. However, this has the drawback of increasing costs due to the need for materials, etc. used for the partitions, etc.

[0008] [Patent Document 1] Patent Publication No. 01-184327 [Patent Document 2] Patent Publication No. 03-133320 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention was made to eliminate the drawbacks mentioned above, and aims to dynamically control the temperature by using a general heater that does not have a variable combustion temperature, making the heating temperature uniform throughout the greenhouse, and making it possible to set any specific area to any temperature without physically separating it with curtains or the like. [Means for solving the problem]

[0010] Each of the plurality of ducts connected to the heater is equipped with an exhaust damper that can be freely controlled to open and close by pressure difference or electromagnetic force, and the opening and closing of each of the plurality of exhaust dampers is controlled based on data from temperature sensors appropriately arranged in the greenhouse, and the operation of the heater is intermittently controlled to dynamically manage the greenhouse in each area within the greenhouse.

[0011] Exhaust dampers that can be freely opened and closed are already available on the market at relatively low cost, and by remotely opening and closing them using an electromagnetic valve or the like, it is possible to minimize the temperature gradient inside a greenhouse, or conversely, to control the temperature by creating individual temperature differences in specific areas without partitions.

[0012] In the conventional method of heating using exhaust air from a duct hose (hereinafter referred to as exhaust heating), an exhaust damper attached to the main duct hose is opened and closed to directly discharge warm air into the greenhouse.

[0013] In the method that utilizes the radiant heat from the surface of the duct hose (hereinafter referred to as radiant heating), a closed branch duct with a closed end is connected to the main duct hose via an exhaust damper, and heating is performed using the radiant heat from the surface of this duct. [Effects of the Invention]

[0014] In exhaust heating, the area around the exhaust dampers is directly heated with hot air from multiple exhaust dampers, allowing the set temperature to be reached quickly and precisely. Radiant heating does not exhaust hot air into the greenhouse, so heat damage to crops is less likely to occur. Also, by recirculating part of the hot air in the duct, heating with high combustion efficiency is possible.

[0015] It is possible to maintain a uniform temperature throughout the greenhouse at minimal cost, and also to cultivate different types of crops in the same greenhouse by controlling the temperature of specific areas of the greenhouse. [Brief explanation of the drawings]

[0016] [Figure 1] Diagram of exhaust air being heated by exhausting it from the exhaust dampers of each duct [Figure 2] Diagram of the layout of each exhaust damper and temperature sensor [Figure 3] Heat is radiated from all closed branch duct hoses to heat the entire greenhouse. [Figure 4] The closed branch duct hose expands and contracts due to the opening and closing of the exhaust damper. [Figure 5]A diagram showing a specific area being heated using a specific closed branch duct hose DETAILED DESCRIPTION OF THE INVENTION

[0017] An example of the above-mentioned exhaust heating will be explained below. As shown in Fig. 1, exhaust dampers 210-232 are arranged on main duct hoses 110-150 connected to parent duct hose 100, and these are opened or closed as desired using solenoid valves or the like to control the exhaust or stop of hot air from heater 500, thereby controlling the temperature of the entire greenhouse by exhaust heating.

[0018] When the heater 500 starts operating, the exhaust temperature of the exhaust dampers 210, 220, 230, 240, and 250 near the exhaust port 510 is high, while the exhaust temperature of the exhaust dampers 212, 222, 223, 224, and 225 far from the heater is low, so a temperature gradient occurs in the greenhouse.

[0019] The temperature data from each temperature sensor 300-390 suspended from the ceiling is analyzed by an agricultural computer 400 to analyze the temperature difference between each zone, and the exhaust damper closest to the zone that has reached the set temperature is closed to cut off the supply of hot air, and in zones where the temperature has dropped below the set temperature, the exhaust damper is opened to continue or resume the supply of hot air.

[0020] The above process is repeated, gradually heating each zone until the entire greenhouse reaches the installation temperature, providing uniform heating without temperature gradients.

[0021] When the exhaust damper is closed, the amount of hot air discharged to the open exhaust damper increases, and this increased amount of hot air is sent to other areas that have not yet reached the set temperature, further increasing the temperature and promoting uniformity of the temperature throughout the greenhouse.

[0022] As shown in Figure 2, in the above example, signal lines wired to each duct are used to identify each exhaust damper, open / close, identify temperature sensors, and collect data, but this can also be done wirelessly.

[0023] Next, a description will be given of the radiation heating method shown in Figures 3 to 5. In the radiation heating method, closed branch duct hoses 111 to 152 with closed ends are connected to the duct hoses 110 to 150 via exhaust dampers.

[0024] Figure 3 shows all exhaust dampers open and warm air from a heater being supplied to all closed branch duct hoses. The entire greenhouse is heated by the radiant heat emitted from the outer surfaces of all of these closed branch duct hoses.

[0025] Then, based on data from the temperature sensors, the agricultural computer determines that one of the areas has reached the installation temperature and closes the corresponding exhaust damper, cutting off the supply of warm air. As a result, the temperature inside the blocked branch duct hose drops, the static pressure also drops, and the hose collapses, stopping heat radiation from its surface.

[0026] If many exhaust dampers are closed, the pressure inside the duct hose will rise excessively. To avoid this, and to prevent the heater from overheating or overloading, the pressure-adjusting exhaust dampers 113, 123, and 133 are opened to exhaust a certain amount of air and stabilize the entire system.

[0027] FIG. 4 shows an example in which hot air is coupled to the closed branch hose duct 111 via the exhaust damper 110, causing it to expand due to static pressure, while the closed branch duct hose 112 is deflated because hot air is not supplied to it due to the closed exhaust damper 111.

[0028] An expanded duct hose radiates radiant heat from its surface, warming the surrounding area, while a deflated duct hose radiates less heat and is unable to heat up, causing the temperature to drop.

[0029] Figure 5 shows that by selectively opening and closing each exhaust damper as needed, warm air can be supplied only to a specific group of closed branch duct hoses, allowing high-temperature heating of the relevant area locally.

[0030] Only the exhaust dampers 240, 241, 250, 251 of the closed branch duct hoses 141, 142, 151, 152 near the specific areas indicated by the dotted lines are opened to supply hot air, and the exhaust dampers 210, 211, 220, 221, 230, 231 in other areas are closed to not supply hot air to the closed branch duct hoses 111, 112, 121, 122, 131, 132. This allows the specific areas to be heated by radiant heat from the branch duct surfaces only, raising the temperature of those areas, while the other areas are not heated because no radiant heat is emitted, making it possible to raise the temperature of only those specific areas.

[0031] As explained above, it is possible to heat agricultural greenhouses with minimal temperature gradients using currently available general greenhouse heaters without controlling the burner combustion temperature or using partitions, and it is also possible to control the temperature of specific areas as desired.

[0032] In the radiant heating method, heating is performed only by radiant heat from the outer surface of the duct hose, so almost no warm air is discharged into the greenhouse (although some air is discharged to adjust the pressure inside the duct hose), and by circulating the heat-exchanged exhaust air again to the intake port 520 of the heater 500 in the exhaust circulation duct 190, further improvement in heating efficiency is possible. [Explanation of symbols]

[0033] 100 Main duct hose 110~150 Main duct hose 111~151 Blocked branch duct hose 190 Exhaust circulation duct 210~252 Exhaust damper 310~390 Temperature sensor 500 heater 510 Heater vent 520 Heater air intake

Claims

1. This greenhouse heating system allows the temperature in each zone in the greenhouse to be freely controlled by appropriately arranging openable and closable exhaust dampers at a plurality of locations on a duct hose connected to a heater, and controlling the opening and closing of the exhaust dampers and the airflow rate of the heater based on temperature data from a plurality of temperature sensors installed in the greenhouse.

2. This greenhouse heating system has exhaust dampers that can be opened and closed suitably arranged at a plurality of locations on a duct hose connected to a heater, and connected to the dampers are closed branch duct hoses, and based on temperature data from a plurality of temperature sensors installed in the greenhouse, the exhaust dampers are controlled to be opened and closed and the amount of air sent from the heater is controlled, thereby making it possible to arbitrarily control the temperature in each zone in the greenhouse.

3. 3. A greenhouse heating system according to claim 1, wherein the exhaust air after heat exchange via each duct hose is returned to the intake port of the heater via the duct hose.

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