Greenhouses - heating networks, electrification

Introduction

Modern agricultural production is a large consumer of fuel and energy resources.

The further development of agriculture and its intensification imply an even wider introduction of electricity into agricultural production and automation of technological processes.

Due to the growth of energy capacities in the agro-industrial complex, as well as the rapid increase in prices for electricity and energy resources, the question of their savings, the creation of energy-saving, environmentally friendly technologies is increasingly being raised.

A significant place in the successful development of integrated electrification is played by the issues of proper design, that is, the choice of the most economical and technologically advanced equipment.

The purpose of the degree design is to consider the issues of electrification of a greenhouse with an area of ​ ​ 1500m2 with a study of the stress state of plants in fruit ratio.

The main task of designing the greenhouse electrification is to minimize manual labor, automate the main technological processes, as well as the safety of maintenance personnel, the requirement of civil defense and the cost-effectiveness of decisions.

1. rationale for the topic of the diploma project

The development of the diploma project is carried out with the aim of finding ways to radically increase labor productivity, reduce the cost of electric energy, choose the optimal composition of the electrical service, as well as the introduction of new technological solutions and equipment that will make it possible to constantly monitor the state of the plant, which can significantly affect their growth, and as a result, the profit of the enterprise.

Control of the microclimate to achieve plant growth optimum determines approximately 90% of the crop. The main components of the microclimate for plant growth are temperature, light, carbon dioxide, relative humidity, water vapor pressure deficit and substrate. The plant needs each of them, but in a combination of their optimal balance to obtain maximum yields and reduce stresses in the plant.

In order to better implement the food programme, it is necessary to find opportunities for maximizing harvests, saving energy consumption by choosing the right equipment, choosing PZA and much more.

This diploma project is considering ways to resolve these issues.

2. Production and economic characteristics of TK Zavyalovsky.

2.1 Characteristics of TC "Zavyalovsky."

The Zavyalovsky greenhouse plant in Udmurtia, with an area of ​ ​ 12 hectares, was built in order to provide the population of Izhevsk with vegetables in the off-season period. The greenhouse plant was organized on the basis of the formation of the Council of Ministers of the Udmurt Autonomous Soviet Socialist Republic of December 9, 1974 under number 383, the order of the Council of Ministers of September 16, 1974 N 597R, the decree of the Presidium of the Udmurt Republican Council of collective farms of November 4, 1974 No. 27 and the task of the Zavyalovsky District Council of collective farms.

The mill consists of two zones: the main production zone and the auxiliary production zone. The first includes: four blocks of winter hangar soil greenhouses, with an area of ​ ​ 3 hectares each, made according to the standard design of TP 810-78, a central heat station, as well as a recently built block of film greenhouses and household premises. The auxiliary zone includes: buildings and structures of transport, mechanical, energy, agricultural and administrative - household groups.

Zavyalovsky greenhouse plant is located on the northern outskirts of the city of Izhevsk, near the village of Khokhryaki. The area occupied by the farm is 96 hectares.

According to climatic conditions, the territory on which the farm is located belongs to the medium moderately - warm, moderately - humid agroclimatic region of our republic. Average temperature itself

cold month - 15 wasps, the warmest +18os. The average annual rainfall is 399 mm. The terrain belongs to the hilly type.

From the northern and eastern borders, the garage massif adjoins the enterprise, from the western there is the village of Khokhryaki, from the southern - the ring road of the city of Izhevsk.

The main production direction in the economy is the cultivation of vegetables and greens. The main industry is crop production.

2.2 Characteristics of the design object in TC "Zavyalovsky."

The design object is a greenhouse with an area of ​ ​ 1500 m2, which is included in the block of winter hangar greenhouses made according to the typical design of TP 810-78.

In this section, I used the data of the model project and its explanations.

The operation of the main production areas is provided for in one shift with a five-day working week. Treatment of plants with poisonous chemicals is produced in the second shift at a 6-hour working day.

Vegetables are grown in greenhouses: cucumbers, tomatoes, green crops. Collected products are transported to the expedition, where they are sorted by quality, packed in boxes, weighed, loaded and sent to the retail network for sale.

Seedlings for winter and autumn planting of cucumbers and tomatoes are grown in seedlings.

For growing vegetables, winter hangar greenhouses with an area of ​ ​ 3000 m2 are adopted. With a connecting corridor, vegetable greenhouses are divided into two independent rooms with an area of ​ ​ 1500m2.

To move plant care mechanisms, transport crops, fertilizers, plant residues along the side fence, an asphalt path with a width of 1.5 m is designed in each greenhouse. At the ends are a gate measuring 3.38 by 2.6 m, which provides entry to the greenhouse T-16M.

Greenhouse heating is a combined heating system (water pipe and air), as well as a underground heating system.

The temperature-wet mode in the greenhouse is maintained automatically according to a given program, depending on the culture, growth period, plant development, degree of illumination. For example, for cucumbers during the onset of fruiting, the air temperature at night should be 18-19C, during the day in inclement weather 24C, in the sun 24-26C.

The optimal humidity for growing cucumbers is 80-90%, tomatoes 60-65%.

Ventilation is natural, carried out through windows in the roof and on the side fences of the greenhouse. Irrigation of plants and humidification of air in greenhouses is carried out using sprinkling systems, which have manual and automatic control.

As a backup, hose watering is provided. Through the sprinkling system, together with irrigation water, are introduced into the soil

mineral fertilizer solutions. To remove excess water during irrigation and soil washing, a drainage system is provided, which includes a drainage layer of sand with a thickness of 200 mm.

2.6 Analysis of causes of electrical equipment failure.

In greenhouses for year-round growing of vegetables, there may be several reasons for the failure of electrical equipment: high humidity, up to 9598%, the use of chemical aggressive drugs and various toxic chemicals. Together, both causes have a significant effect, since a chemically active medium leads to faster breakdowns of control equipment and isolation of other electrical equipment.

Another reason is the lack of money to replace obsolete electrical equipment with better and better quality, as well as, sometimes, a complete lack of operational maintenance of the equipment during its operation.

A device for determining the stress state of plants.

Control of the microclimate to achieve plant growth optimum determines approximately 90% of the crop. To maximize the yield and improve the quality of fruits, the crop grower should create an optimal microclimate in the greenhouse. The main components of the microclimate for plant growth are: temperature, light, carbon dioxide, relative humidity, water vapor pressure deficit and substrate.

The most modern greenhouses regulate the needs of plants using a computer. The microclimatic computer allows for more even control of these changes as opposed to the start and end of the cycle control of earlier "mechanical" microclimate systems. Planned uniform control of microclimate levels fluctuations in microclimate conditions, reducing plant growth rate and maximum yield.

However, even though the computer is microclimatic, its sensors only indirectly measure the state of plants and what the plant needs in turn. For example, air temperature is an indirect measurement of the temperature of plant tissues. On hot sunny days, the tissue temperature of the upper leaves can be 810 ° C higher than the air temperature or the tissue temperature of the leaves located in the lower tiers. The accuracy of the sensors, calibration, location, and microclimate inside the greenhouse can also affect the accuracy of the microclimate readings in the greenhouse.

For example, a temperature difference of 1 ° C with respect to a given daily temperature in the early stages of tomato cultivation may result in a loss of 1 kg/m2 of crop. Thus, the plant grower must rely on their ability to perceive the plant and regulate the microclimate based on what the plant expresses.

The key to managing plant yields is maintaining the "plant balance." The balance of the plant is the balance between flowering and fruiting (generativity) and leaf and root formation (vegetation), based on the growing medium at a certain stage in the growing cycle. For example, in low light conditions in early spring, it was important to maintain average daily temperatures in order to be able to provide sufficient photo-synthetic assimilates (sugars) and direct them to fruit formation, but also to maintain strong plant development (leaves and roots). The decrease in average daily temperatures limits the formation of assimilates produced with reduced illumination during the day, leads to the preservation of both vegetative and generative needs. This leads to the fact that the "speed of the plant" or the intensity of development slows down. The lack of adjustment of the plant imbalance can lead to a decrease in the yield and low quality of fruits. The microklimate of the greenhouse should also be taken into account in terms of the development of insect and disease control strategies, as well as strategies for the health of workers: their without danger and labor efficiency.

In some cases, the microclimate for these factors may be counterproductive to plant needs and thus a trade-off must be achieved.

5.2.Base the necessity of co-movement control.

Most vegetable growers believe that the plant should have a good turgor in the morning. During the day, the plant must cool and intensively evaporate moisture. When the plant's need for water increases so that the plant root system cannot satisfy it, the plant begins to take moisture from the cells. When a plant cannot restore turgor at night, problems arise. Also, specialists should be very careful about ventilation in cold weather, and when the temperature difference is 10110. The movement of juice in the plant depends on the amount of light that enters the plant. R. Chrotsholton believes that a higher temperature is preferable, in which case the juice movement will be more uniform.

Changes in the diameter of the main stem indicate to the vegetable grower that it is preferable for the leom to increase the temperature earlier. Uniform heating conditions shall correspond to the amount of solar radiation.

To the same extent, evaporation is highly dependent on solar radiation, and the plant reacts poorly to heating. The sun defines everything. In January - February, the plant is not yet under full load. In the evening during this period, heating is used to accelerate the staining of fruits.

It was possible to establish a strong dependence of the plant's CO2 consumption on relative air humidity. With a relative humidity of more than 80%, CO2 absorption by the plant increases by almost 100% compared to a relative humidity of 70%. Therefore, the question arises as to what extent it is useful in summer to dose a large amount of CO2 at low relative air humidity and vent.

The juice motion meter has hitherto been fixed to the pa-son or shoot at the top of the plant so that the sensor can measure a small flow of juice. In this case, it is impossible to determine when the roots begin to actively pump water through the main stem. In addition, the sun causes deviations at the top of the plant, since the measurement process occurs for low amounts of heat. Therefore, the sensor will be placed on the main stem at the bottom of the plant.

Safety measures for greenhouse works

Greenhouses belong to raw rooms with conductive floors, that is, to especially dangerous rooms. For the purpose of safe maintenance of electrical installations, all metal non-current-carrying parts that are not normally energized, but which may be due to pro-battle insulation, must be grounded. The supply cable trays shall be grounded and shall be electrically inseparable over the entire length.

Earthing shall be used for de-energizing operations. The electrician is allowed to replace fuse inserts without de-energizing. Replacement of lamps without de-energizing, do not perform any work directly on current-carrying parts. Electrified machines powered by a flexible cable used in the greenhouse farm must have devices for monitoring the integrity of the busbar in the supply cable, as well as protective current disconnection in the zero wire. It is advisable to use protective disconnection by leakage current.

7.5 Safety measures during operation of the device for determination of stress state of plants by movement.

The plant stress detection device includes an electromagnetic sensor powered by a 5V source equipped with a low frequency rectangular pulse generator, which does not pose a danger to the life of operators.

The device meets the following requirements:

1. According to the degree of protection against electric shock, it belongs to protection class 1 in accordance with the requirements of GOST 2610489.

2. Clamp of protective grounding of the device for determination of stressful co-standing of plants must be made in accordance with GOST 12209194 .

3. The sensor must have the inscription: "ATTENTION! Before any connection, the protective grounding clamp shall be connected to the protective conductor. "

4. Connect the protective grounding clamp of the sensor to the protective grounding bus before other connections to the sensor and the 80MC51GB board, and disconnect after all disconnections.

5. Breaking the 80MC51GB analog channel ground circuit and signal source can damage the 80MC51GB input multiplexers.

6. When repairing the sensor, replace any element, install or remove the 80MC51GB board only when the power is off.

7.6 Fire Safety at Zavyalovsky Greenhouse Plant

During a fire in electrical installations it is forbidden to extinguish the fire with water, liquid fire extinguishers. Dry sand, powder or carbon dioxide extinguishers should be used to extinguish the fire. Two fire protection panels, four fire extinguishers OU - 10, 5 fire extinguishers OKhP10, as well as 2 boxes with sand should be installed in the greenhouse.

It is forbidden to use household appliances in production premises.