JP2008191056A - Snowfall sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a snowfall sensor having a simple configuration, low energy consumption, and high detection accuracy. <P>SOLUTION: The snowfall sensor includes an outside air temperature sensor 12 for detecting an outside air temperature, a snow-receiving plate temperature sensor 18 for detecting the temperature of a snow-receiving plate 14, and a heater 20 for heating the snow-receiving plate 14. The snowfall sensor is provided with a control device 24 that controls the heater 20 so that the temperature of the snow receiving plate 14 becomes substantially equal to the outside air temperature or a predetermined plus snowfall temperature due to the heater 20. With the control device 24, supply energy corresponding to the fusion latent heat of snow adhering to the snow receiving plate 14 is detected, and thus, the snowfall intensity is detected. The snow receiving plate temperature sensor 18 is covered with a heat insulating material 22 on the back surface side. The front surface side of the snow receiving plate temperature sensor 18 contacts with the snow receiving plate 14 formed of a metallic plate in contact with the heater 20 and the snow receiving plate temperature sensor 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a snowfall sensor that is used to control a snowmelt device or other equipment that supports snowfall and that electrically detects snowfall.

  Conventionally, as a snowfall detection device, a snow receiving plate having a pair of electrodes on the surface, a moisture detecting unit that detects moisture adhering to the snow receiving plate by each electrode, an outside air temperature sensor that detects outside air temperature, and a snow receiving Some have a snow receiving plate temperature sensor for detecting the temperature of the plate and a heater for heating the snow receiving plate. When the detected temperature of the outside air temperature sensor is below the temperature at which snow can fall, and when it is detected that snow has fallen on the snow receiving plate and the electrodes are electrically connected to each other by the moisture of the snow, a predetermined snow melting device is installed. It is to be operated. This snowfall detecting device drives the heater when the temperature detected by the outside air temperature sensor becomes a predetermined reference temperature or lower, or when each electrode of the snow receiving plate detects moisture. This prevents snow from accumulating on the snow receiving plate.

  In addition, as a snowfall sensor, there exist some which are disclosed by patent document 1, for example. This snowfall sensor is designed to keep the temperature of the snow receiving plate at a predetermined temperature even when external conditions such as outside air temperature and wind strength change, and detects the temperature of the snow receiving plate. Snow receiving plate temperature detecting means, heating amount controlling means for controlling the heating amount of the heating means, and when the outside air temperature is lower than a predetermined reference temperature and moisture of the snow receiving plate is not detected, The heating temperature is set to the first set temperature, and when the outside air temperature is lower than the reference temperature and moisture of the snow receiving plate is detected, the heating temperature of the snow receiving plate is set to the second set temperature, Control means for controlling the heating amount of the heating means based on the detected temperature of the snow receiving plate temperature detecting means so that the heating temperature of the snow receiving plate becomes each set temperature. As a result, the heating amount of the heating means is controlled based on the detected temperature of the snow receiving plate temperature detecting means, so that the snow receiving plate can be heated even when external conditions such as the outside air temperature and wind strength change. The temperature is controlled to be constant at each set temperature.

In addition, as disclosed in Patent Document 2, it has been proposed to determine the snowfall intensity based on the signals of the electrode pairs provided at a plurality of locations on the snow receiving plate.
Japanese Patent Laid-Open No. 11-52065 JP 2001-27679 A

  However, each of the above conventional techniques includes a heater that heats the snow receiving plate, and detects snowfall when the electrode pair of the snow receiving plate is conducted. The structure of the snow receiving plate is complicated, and snow melting There was a problem that the power consumption for use was large. In addition, there is a possibility that the electrical resistance changes due to the wetting of the snow receiving plate, which may cause erroneous detection, and that rain and snow must be distinguished from each other depending on the outside temperature.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a snowfall sensor having a simple configuration, low energy consumption, and high detection accuracy.

  The present invention relates to an outside air temperature sensor that detects an outside air temperature, a snow receiving plate that is installed with its surface facing substantially upward and on which snow falls, a snow receiving plate temperature sensor that detects the temperature of the snow receiving plate, and the snow receiving plate And a controller for controlling the heater connected to the output of the snow-receiving plate temperature sensor, supplying energy to the snow-receiving plate by the heater, and Control is performed by the control device so as to be substantially equal to a reference temperature which is a predetermined plus snowfall temperature slightly higher than 0 ° C., and supply energy corresponding to the melting latent heat of the snow attached to the snow receiving plate is controlled by the control device. It is a snowfall sensor that detects snowfall intensity by calculating.

  The snow receiving plate temperature sensor is covered with a heat insulating material on the back side, and the surface side is in contact with a snow receiving plate made of a metal plate in contact with the heater and the snow receiving plate temperature sensor.

  When the outside air temperature becomes 0 ° C. or lower, the control device sets the snow receiving plate temperature to a positive constant value slightly higher than 0 ° C. Further, the surface of the snow receiving plate may be provided with a titanium oxide film.

  The present invention also provides a photovoltaic power generation panel that generates power with light, a snow receiving plate that is integrally formed with the protective glass on the surface of the photovoltaic power generation panel and that snows on the surface, and detects the temperature of the snow receiving plate. A snow receiving plate temperature sensor, a heater for heating the snow receiving plate, and a control device for controlling the heater connected to the output of the snow receiving plate temperature sensor, and supplying energy to the snow receiving plate by the heater The snow receiving plate is controlled by the control device so that the snow receiving plate is substantially equal to a reference temperature which is a predetermined plus snowfall temperature slightly higher than an outside air temperature or 0 ° C., and melting of snow adhering to the snow receiving plate is performed. The snowfall sensor detects the snowfall intensity by calculating supply energy corresponding to latent heat by the control device.

  The snowfall sensor of the present invention does not require an electrode pair for detecting conduction by snowmelt water, and has a simple structure. Furthermore, since the heater is maintained at a temperature equal to the outside air temperature or a temperature close to a predetermined 0 ° C., the heater consumes less energy and is economical.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of the present invention. A snowfall sensor 10 according to this embodiment is in contact with the outside air at a position where no snow adheres to the outside air temperature sensor 12 for detecting the outside air temperature, and the surface is almost upward. And a snow receiving plate 14 that is installed facing the snow and on which snow falls, and a snow receiving plate temperature sensor 18 that detects the temperature of the snow receiving plate 14. A heater 20 that heats the snow receiving plate 14 is provided on the back surface side of the snow receiving plate 14, and the heater 20 is controlled by the heater 20 so that the temperature of the snow receiving plate is substantially equal to the outside air temperature or a predetermined snowfall temperature. A control device 24 such as a computer is connected.

  The snow receiving plate temperature sensor 18 is surrounded by a heater 20, the back side is covered with a heat insulating material 22, and the front side is a snow receiving plate 14 made of a metal plate in contact with the heater 20 and the snow receiving plate temperature sensor 18. It touches. The snow receiving plate 14 is installed at an inclination, and the snowfall is quickly melted on the snow receiving plate 14 and remains as water droplets on the surface. When the water droplets become larger, the snow receiving plates 14 are discharged by the inclination of the snow receiving plate 14.

  The control device 24 controls the heater 20 so that the temperature of the snow receiving plate 14 by the snow receiving plate temperature sensor 18 is equal to the temperature of the outside air temperature sensor 12. When the outside air temperature is 0 ° C. or lower, the temperature of the snow receiving plate 14 is set to a reference temperature that is a constant value close to 0 ° C., for example, 1 ° C. The controller 24 detects the supply energy corresponding to the melting latent heat of the snow adhering to the snow receiving plate 14, controls the temperature of the snow receiving plate 14, and detects the snowfall intensity from the energy necessary for this control. The snow receiving plate 14 is provided with a titanium oxide film 16.

  In the control method in the snowfall sensor 10, first, the temperature of the snow receiving plate 14 is controlled by the heater 20 so as to coincide with the outside air temperature. In a state without snowfall, the outside air temperature by the outside air temperature sensor 12 and the temperature by the snow receiving plate temperature sensor 18 of the snow receiving plate 14 are equal even if the heater 20 is not energized. The back surface of the snow receiving plate 14 is thermally insulated by a heat insulating material 22. And the heat balance of the snow receiving board 14 is represented like Formula (1) roughly.

Here, T is the temperature of the snow receiving plate, T _A is the outside air temperature, T _Q is the temperature of the snow (rain), q is the heater power, q _I and q _B are the solar radiation energy and radiation energy, respectively. Light receiving area, C is the heat capacity of the snow receiving section, h is the heat transfer coefficient between the snow receiving section and the outside air, LH is the latent heat of fusion of water, Cp is the specific heat of water, Q is the amount of snowfall (rainfall) [g / m ² s].

  The surface temperature of the snow receiving plate 14 is warmed by solar radiation and cooled by snowfall. That is, by controlling q as shown in Expression (2), the heat radiation amount of the snow receiving plate 14 and the energy supplied by the heater 20 become equal, and the temperature matches the outside air temperature. Actually, proportional control shown in the following formula (3) is performed so that the temperature of the snow receiving plate 14 and the outside air temperature are matched.

Here, K is a proportional sensitivity. In an equilibrium state, the snowfall amount Q can be calculated from the calorific value q '. Specifically, the heater 20 uses an AC power supply and performs PWM control by zero crossing. For the control, digital proportional control based on the equation (3) is performed by the control device 24, and the sampling period is, for example, about 1 second.

  Next, an example of use of the snowfall sensor 10 will be described below with reference to FIG. In this usage example, the snowfall sensor 10 is used for melting snow on the photovoltaic power generation panel 11. As shown in FIG. 2, the photovoltaic power generation panel 11 is a rectangular plate-shaped body having a predetermined size, and is provided with a solar cell module including a solar cell, a circuit board, and the like. A protective glass for the surface of the solar cell module is provided on the surface side of the solar cell module, and a snow receiving plate 14 that is also used as the protective glass and is flush with the solar cell module is integrally provided in contact with the solar cell module. 10 is formed integrally with the photovoltaic power generation panel 11.

  As shown in FIG. 2, the photovoltaic power generation panel 11 is provided with a plurality of photovoltaic power generation panels 11 arranged flat on one slope of the roof 30 of the house 28. An eave ridge 32 is provided at the eaves end of the roof 30, and a water collecting channel 34 that collects rainwater is connected downward at a corner of the eaves 樋 32, and a lower end portion of the water collecting channel 34 is connected to a water storage tank 36. Has been. In addition, the snowfall sensor 10 should just be integrally formed in one sheet | seat of the some photovoltaic power generation panel 11. FIG.

  Between the ridge portion 38 and the photovoltaic power generation panel 11 of the roof 30, a plurality of water spray nozzles 40 are provided along the ridge portion 38 substantially in parallel with each other, and four here are provided at substantially equal intervals. Each water spray nozzle 40 is connected to a water supply path 42 for taking rainwater.

  The water supply channel 42 is bent downward from the corner of the roof 30 and is connected to the water storage tank 36. A supply pump 44 that sends rainwater in the water storage tank 36 to the watering nozzle 40 is provided in the middle of the water supply path 42. A pump controller 46 having a control unit is connected to the supply pump 44, and the pump controller 46 is connected to the control device 24. The pump controller 46 drives and controls the supply pump 44 according to a signal from the control device 24. The supply pump 44 is also provided with a manual switch.

  In addition to the watering nozzle 40, a supply pipe 52 connected to water supply equipment such as a flush toilet 48 and a faucet 50 is branched and provided in the water supply path 42. Each supply pipe 52 may be provided with a supply pump or a valve. More preferably, a filter or a sedimentation tank for removing dust or the like is provided on the inlet side or the outlet side of the water storage tank 36.

  The water tank 36 is provided with a water supply device for a water pipe and a float that is a water level sensor that detects the water level floating on the water surface in the water tank 36. And when there is little rainfall and the water level in the water storage tank 36 falls below a certain limit, the float moves downward together with the water level, and tap water is automatically replenished from this water supply device. In order to detect the water level, a sensor other than the float may be provided.

  Next, the operation of the snowfall sensor 10 of this embodiment will be described. First, at the time of snowfall, a difference between the temperature measured by the snow receiving plate temperature sensor 18 of the snowfall sensor 10 and the temperature of the outside air measured by the outside air temperature sensor 12 is detected, and the snowfall sensor whose temperature is lower than the outside air due to snow accumulation. The 10 snow receiving surfaces 14 are brought into a state equal to the temperature of the outside air by energization of the heater 20. And in order to set it as this state, the electric power consumed by the heater 20 is calculated by the control apparatus 24, and is converted into snowfall intensity. Further, the controller 24 sets a water spray amount necessary for melting the snow amount based on the converted snowfall intensity, sends a signal to the pump controller 46, and drives the supply pump 44. Then, rainwater in the water storage tank 36 is sprinkled from the watering nozzle 40. Thereby, snow melting on the surface of the solar power generation device 11 is performed to prevent the sunlight from being blocked, and power generation is continued.

  The snowfall sensor 10 can be used as a temperature sensor for the photovoltaic power generation panel 11 in summer and the like. First, when there is rain, rainwater that has fallen on the roof 30 is received by the eaves wall 32, and the rainwater passes through the water collection channel 34 and is collected in the water storage tank 36. And in the situation where there is much solar radiation and the temperature of the photovoltaic power generation panel 11 rises, the temperature of the photovoltaic power generation panel 11 is measured by the outside air temperature sensor 12 of the snowfall sensor 10, and the control device 24 lowers it to the target temperature. A necessary watering amount is set and a signal is sent to the pump controller 46 to drive the supply pump 44. And the rainwater in the water storage tank 36 is sent to the watering nozzle 40 with the supply pump 44, and water is sprayed from the watering nozzle 40 to the surface of the photovoltaic power generation panel 11 and cooled. Thereby, the temperature rise of the solar power generation panel 11 is suppressed, and high photoelectric conversion efficiency is maintained.

  The electric power generated by the solar power generation panel 11 may be used for the electric power of the supply pump 44 and the home appliance 54, or may flow to the commercial power supply system via the power conditioner 60 and the distribution board 58, resulting in insufficient power. In this case, it is better to purchase electricity from a commercial power system.

  The snowfall sensor 10 of this embodiment does not require an electrode pair for detecting conduction by snowmelt water on the snow receiving surface, and has a simple structure. Furthermore, since the heater 20 may be maintained at a temperature equal to the outside air temperature or a reference temperature close to a predetermined 0 ° C., energy consumption by the heater 20 is small and economical.

  The snowfall sensor of the present invention can also be used for snow removal on roads and other areas, or other devices that operate in response to snowfall, in addition to the snow removal of the photovoltaic power generation panel of the above embodiment. .

  Moreover, the snowfall sensor may be located above the water spray nozzle above the photovoltaic power generation panel. In this case, snow can be detected without being affected by water spray.

Next, an example in which an operation experiment of the snowfall sensor of the present invention was conducted will be described. Here, the snow receiving plate temperature, the outside air temperature, and the output to the heater were taken in from the snowfall sensor 10 at a sampling time of 1 second, and at the same time, the snow mass on a certain area was measured with an electronic balance. An example of the measurement result is shown in FIGS. 3 and 4 show the change over time of the output to the heater, which is converted to snowfall intensity [g / m ² s] using water solidification latent heat 334 [J / g]. The thick line in the figure shows the average snowfall intensity by the electronic balance that is being measured simultaneously. FIG. 4 is a comparison between the integrated value and the measured value (thick line) of the amount of snow by an electronic balance. Here, the experiments shown in FIGS. 3 to 6 are performed at night, and are not affected by solar radiation, and are considered to be during snowfall and have little influence of radiation.

  As shown in FIG. 3, the output to the heater 20 is larger than the actual amount of snowfall. This is because the temperature of the snow receiving plate is higher than the outside air temperature (average of this time zone is about 0.5 ° C.), and the snow receiving plate is cooled by heat transfer with the outside air.

  Since the snowfall sensor 10 creates an equilibrium state between the snow receiving plate temperature and the outside air temperature, the amount of snowfall cannot be measured when the outside air temperature falls below the freezing point. Therefore, when the outside air temperature was below 1 ° C., the snow receiving plate temperature was measured by a method of controlling to 1 ° C. which is a positive reference temperature. The results are shown in FIGS. As in the experimental results of FIGS. 3 and 4, the output to the heater 20 is larger than the actual amount of snowfall, but because the snow receiving plate temperature is higher than the outside air temperature, it is cooled by heat transfer. . However, the error is relatively small compared to the experiments of FIGS.

It is a longitudinal cross-sectional view of the snowfall sensor of this invention. It is a perspective view which shows the usage method of the photovoltaic power generation panel using the snowfall sensor of one Embodiment of this invention. Snow falling on a snowfall sensor according to an embodiment of the present invention, converted to snowfall intensity using the solidification latent heat of water (thin line) at an outside air temperature of 1.3 ° C., and average snowfall by an electronic balance simultaneously measured It is a graph which shows intensity | strength (thick line). An electronic balance that simultaneously measures a time integral value (thin line) of snow falling on a snowfall sensor according to an embodiment of the present invention, converted to snowfall intensity using solidification latent heat of water at an outside air temperature of 1.3 ° C. It is a graph which shows the time integral value (thick line) of the average snowfall intensity by. The average of the snow falling on the snowfall sensor of one embodiment of the present invention, converted into snowfall intensity using the solidification latent heat of water at an outside air temperature of -0.5 ° C (thin line), and the electronic balance simultaneously measured It is a graph which shows snowfall intensity (thick line). The time integral value (thin line) of the snow falling on the snowfall sensor according to one embodiment of the present invention, converted into snowfall intensity using the solidification latent heat of water at an outside air temperature of −0.5 ° C., and the electron simultaneously measured It is a graph which shows the time integral value (thick line) of the average snowfall intensity | strength by a balance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Snowfall sensor 11 Solar power generation panel 12 Outside temperature sensor 14 Snow receiving plate 16 Titanium coat layer 18 Snow receiving plate temperature sensor 20 Heater 22 Heat insulating material 24 Controller

Claims (5)

  An outside air temperature sensor that detects the outside air temperature, a snow receiving plate that is installed with its surface facing almost upward, and on which snow falls, a snow receiving plate temperature sensor that detects the temperature of the snow receiving plate, and a heater that heats the snow receiving plate And a control device for controlling the heater connected to the output of the snow receiving plate temperature sensor, supplying energy to the snow receiving plate by the heater, and the snow receiving plate is slightly less than an outside air temperature or 0 ° C. Is controlled by the control device so as to be substantially equal to a reference temperature, which is a predetermined high snowfall temperature, and the control device calculates a supply energy corresponding to the latent heat of melting of the snow adhering to the snow receiving plate. A snowfall sensor characterized by detecting intensity.   The back surface of the snow receiving plate temperature sensor is covered with a heat insulating material, and the front surface is in contact with a snow receiving plate made of a metal plate in contact with the heater and the snow receiving plate temperature sensor. Item 1. A snowfall sensor according to item 1.   2. The snowfall sensor according to claim 1, wherein when the outside air temperature becomes a temperature of 0 ° C. or lower, the control device sets the snow receiving plate temperature to a constant value slightly higher than 0 ° C.   The snowfall sensor according to claim 1, wherein a surface of the snow receiving plate is provided with a titanium oxide film. A photovoltaic power generation panel that generates electricity with light, a snow receiving plate that is integrally arranged with the protective glass on the surface of the photovoltaic power generation panel and on which snow falls, and a snow receiving plate temperature sensor that detects the temperature of the snow receiving plate A heater for heating the snow receiving plate, and a control device for controlling the heater connected to an output of the snow receiving plate temperature sensor, supplying energy to the snow receiving plate by the heater, Supply corresponding to the melting latent heat of snow adhering to the snow receiving plate, which is controlled by the control device so that the snow plate is substantially equal to a reference temperature which is a predetermined plus snowfall temperature slightly higher than the outside air temperature or 0 ° C. A snowfall sensor, wherein energy is calculated by the control device to detect snowfall intensity.

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