Crop phytotron capable of accurately and uniformly controlling temperature of cyclone airflow

Abstract

The invention provides a crop phytotron capable of accurately and uniformly controlling temperature of cyclone airflow. According to the crop phytotron capable of accurately and uniformly controllingthe temperature of cyclone airflow, at least two air supply ports, two air return ports and two auxiliary fans are diagonally arranged to form a cyclone airflow field of the phytotron. According to the temperature control, two-stage heat balance and two-variable temperature control measures are adopted: in the first-stage energy balance, cold water and hot water are prepared firstly; and in the second stage, cold water or hot water is used for balancing the heat exchange capacity between the phytotron and the outside. Two variables for adjusting energy are the water inlet flow and the water inlet temperature of an air heat exchanger. According to the crop phytotron, a temperature control model of the crop phytotron is derived, and a theoretical basis is provided for accurate temperature control of the crop phytotron; three signals need to be utilized for temperature control are provided and include solar radiation, enclosure structure heat transfer flow and indoor temperature, and corresponding temperature difference values are provided; embodiments are described; and the innovation of the theory and the technology has important significance and practical value.

Description

technical field [0001] The invention relates to the field of climate chambers, in particular to an artificial plant climate chamber with precise and uniform temperature-controlled whirlwind air flow. Background technique [0002] Plant growth is affected by a variety of environmental factors: light, temperature, relative humidity, carbon dioxide, etc. In order to speed up the progress of modern agriculture, crop artificial climate chambers are widely used, a kind of artificial control, change and reproduction of various meteorological conditions in a closed system The experimental equipment is used to study the relationship between the growth, flowering and fruiting of crops and these factors; the current artificial climate chamber can be divided into three types according to the structure: box type, room type and mixed type: box type, small in size, adjustable Good performance, but the working area is generally only a few square meters, which cannot simulate the production ...

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Problems solved by technology

[0002] Plant growth is affected by a variety of environmental factors: light, temperature, relative humidity, carbon dioxide, etc. In order to speed up the progress of modern agriculture, crop artificial climate chambers are widely used, a kind of artificial control, change and reproduction of various meteorological conditions in a closed system The experimental equipment is used to study the relationship between the growth, flowering and fruiting of crops and these factors; the current artificial climate chamber can be divided into three types according to the structure: box type, room type and mixed type: box type, small in size, adjustable Good performance, but the working area is generally only a few square meters, which cannot simulate the production of large-scale crops, and is not suitable for the selection of improved rice varieties; the house type is a large-scale complete building, which consists of a machine room, a control center and several different sizes. The working area can be tens to hundreds of square meters; the mixing room is to place several chambers in the room-type artificial climate room;

[0003] In the research of rice selection and breeding, high temperature has caused harm to the growth and yield of rice, especially in the stage of rice heading and flowering; in recent years, extreme weather has occurred frequently, and high temperature and heat damage have seriously affected rice production; In 2013 and 2016, the high-temperature weather in the Jianghuai and Yangtze River basins in China significantly reduced the seed setting rate of some rice varieties, causing great production losses; different rice varieties have different sensitivities to high temperatures. Individual population quality, physiological characteristics, photosynthesis, quality and yield formation have obvious effects; flower organs and physiological characteristics are significantly different between heat-resistant and heat-intolerant varieties; screening and identification of rice heat-resistant varieties is of great significance to ensure food security ; In order to speed up the progress of rice seed selection, it is necessary to build an artificial climate chamber for identifying the heat resistance of rice, which can only be a chamber artificial climate chamber with a larger area; The room air conditioning method is mostly used, through the refrigerator and the air circulation system in the artificial climate room, according to the difference between the room temperature signal and the set temperature, the speed of the radiator fan is controlled, or the refrigerator is turned on and off, to achieve high temperature in the artificial climate room Air temperature adjustment; the indoor air circulates between the air heat exchanger of the refrigerator and the crops in the artificial climate room; when the indoor temperature is too high, the air heat exchanger of the refrigerator is an evaporator, and the evaporation temperature of the refrigerant is between 3- At about 8°C, the high-temperature gas in the artificial climate room will condense and precipitate a lot of moisture in the air on the surface of the low-temperature evaporator, reducing the humidity in the artificial climate room; in addition, according to the design requirements of the refrigerator, the temperature difference between the inlet and outlet of the air heat exchanger is 8°C or above, and the artificial climate chamber for identifying the heat resistance of rice requires that the temperature uniformity in the rice panicle layer be within 1°C; the existing artificial climate chamber is used as an artificial climate chamber, and the usual artificial climate chamber refers to the air supply and return of the room air conditioner. The wind mode only arranges a single air supply port, the air supply port is arranged above one side of the artificial climate chamber, and the return air is on the back side of the air supply port of the heat exchanger; this air supply method compares the temperature difference on the air streamline in front of the air supply port Large, cold or hot air is difficult to spread evenly in the room, and the wind at the air outlet will be short-circuited and reflowed before fully exchanging heat with the indoor air because the air pressure of the air outlet is higher than that of the air inlet, and it is difficult to achieve a uniform indoor temperature field. The four corners of the rice panicle layer are the dead corners of the air flow, which cannot fully exchange heat, and the temperature at the four corners will be quite different from that in the central area; it is also reported that in order to improve the indoor air flow in the artificial climate chamber of crops in Japan, the upper air supply and the trench are used. The way of return air; if there are enough air outlets and trenches on the top of this air supply mode, the uniformity of air flow can be improved to a certain extent, but the indoor air temperature still has a difference in the height layer, and the trenches are linear. The wind speed far away from the trench on both sides of the trench is small, and the temperature uniformity of the plane layer is difficult to be high. In addition, the way of return air from the trench also reduces the effective area of ​​the crop artificial climate laboratory.

[0004] According to the temperature control method of the above-mentioned crop artificial climate chamber, three existing problems are attributed: (1) the airflow has a dead angle, and it is difficult to obtain a uniform temperature field; (2) a single room temperature signal is used as the start and stop of the temperature control system, and the response lags behind the outside world Changes in the heat transfer of the artificial climate chamber, especially the change of solar radiation; (3) Direct temperature control by the refrigerator, the temperature difference is too large, and the temperature of the evaporator of the refrigerator is too low, it is easy to reduce the humidity of the artificial climate chamber

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