RU2737668C1 - Greenhouse for growing vegetables - Google Patents

Abstract

FIELD: agriculture.SUBSTANCE: invention relates to the field of agricultural structures. Greenhouse for growing vegetables is arranged in the form of an air closed chamber located on the ground surface. From above it is limited by a convex transparent cover. Greenhouse can be single-section and multi-section. Outer walls are continuous. Internal walls at multisection structure are not solid and are made of separate posts embedded in soil and combined in transverse tightening, and in longitudinal - by crossbars. Device for reducing air temperature in air closed chamber of greenhouse is combined with roof and is made in the form of double-glazed window from two parallel glass with cavity between them, filled with water, if necessary flowing. In the daytime the cavity of the air chamber of the greenhouse is heated by solar radiation. At the same time part of solar radiation is absorbed by double-glazed window water, and part is reflected. From the chamber, excess heat is diverted into the water from the double-glazed window. Air temperature inside greenhouse cavity is set proceeding from rational temperature mode for vegetables growing. Water temperature in the double-glazed window cavity is calculated proceeding from the heat balance estimation. Glazing unit can be quite powerful. Then water is cooled at night due to heat exchange with external air. But it is more effective and reliable to equip the water cooling system, which is connected to the double-glazed window cavity by means of pipes. Efficiency of the proposed technical solution consists in the fact that in conditions of a hot climate it is possible to provide a normal temperature mode of an air chamber, using the whole light day without artificial obscurity.EFFECT: proposed design can be widely used for other premises in hot climate, for example, various public buildings, cafes, etc.1 cl, 3 dwg

Description

The invention relates to the field of agricultural facilities.

A greenhouse for growing vegetables is known, made in the form of an air closed chamber located on the natural surface of the soil and bounded from the sides and ends by external walls, and from above with a transparent convex roof upward (V.I. Nazarova, Modern greenhouses and hotbeds. ISBN: 978-5 -3860-3061-2. Publishing house: Ripol Classic, 2011, p. 17).

The disadvantage of such a greenhouse is that when heated by the sun, a greenhouse effect is created, and overheating of the air inside the greenhouse takes place, which leads to the death of plants. Ventilation by providing communication between the interior space and the outside air has an effect as long as the outside air temperature does not exceed certain values. Otherwise, the desired effect is not achieved.

A greenhouse for growing vegetables is known, made in the form of an air closed chamber located on the natural surface of the soil and limited from the sides and ends by external walls, and from above with a transparent convex roof upward, and equipped with a device for lowering the air temperature within the chamber (Guidelines for the design of greenhouses and greenhouses (to SNiP 2.10.04-85), GiproNIISelProm. - M .: Stroyizdat, 1988, p. 22). This greenhouse contains a curtain that provides periodic shading.

The disadvantage of such a greenhouse may be the harmful effect of shading in terms of a lack of light for plants.

The purpose of the proposed design is to eliminate periodic shading while ensuring the normal temperature regime of the closed air chamber of the greenhouse.

This goal is achieved by the fact that the greenhouse for growing vegetables includes an air closed chamber located on the natural surface of the soil and bounded from the sides and ends by external walls, and from above with a transparent convex roof upward. The greenhouse is equipped with a device for lowering the air temperature within the chamber, while the device to lower the air temperature and the roof are combined and made in the form of a double-glazed unit of two parallel glasses with a cavity between them filled with water. The greenhouse for growing vegetables is equipped with a water cooler connected to the cavity of the glass unit of the roof with supply and discharge pipes, which contain end sections within the roof, and the end section of the outlet pipe is located on the ridge of the upwardly convex roof, and the end section of the outlet pipe is located in the lower part of the roof. while the end sections of the pipes are made perforated and located within the cavity of the glass unit.

In addition, a greenhouse for growing vegetables can be made from a series of adjacent sections with self-contained roofs and common internal walls made of separate racks united by a common crossbar.

The essence of the invention is illustrated by drawings, where:

- in Fig. 1 schematically shows a cross section of the proposed greenhouse for growing vegetables;

- in Fig. 2 shows a diagram of heat flows in the proposed greenhouse during the day;

- in Fig. 3 shows a diagram of heat flows in the proposed greenhouse at night.

A greenhouse for growing vegetables (Fig. 1) is arranged in the form of an air closed chamber located on the surface of 1 soil 2. From above it is bounded by a convex transparent roof 3. The rational form of the bulge is a gable profile. In this case, the angle 4 of the slope of the roof parts "a" can be determined in the range of 30-60 ° C. The greenhouse can be single-section or multi-section, as shown in FIG. 1. External walls 5 are solid, which is necessary to ensure the closedness of the air chamber. Their geometric invariability is ensured by buttresses 6. The inner walls are not solid and are made of separate racks 7 embedded in the ground 2 and united in the transverse direction by puffs 8, and in the longitudinal direction - by crossbars 9. In this technical solution, a device for lowering the air temperature in an air closed the greenhouse chamber is combined with the roof and is made in the form of a double-glazed unit of two parallel glasses with a cavity between them filled with water.

A greenhouse for growing vegetables can be equipped with a water cooling system, which consists of a water tank 10, a water cooler 11, a fence 12, inlet and outlet pipes 13, 14, connected to the glass roof units 3.

The supply pipes 13 end with a section 15 located on the roof ridge within the cavity of the glass unit filled with water. The outlet pipes 14 begin with a section 16 located in the lower part of the roof, also within the cavity of the glass unit filled with water.

The outlet pipes 14 begin with a section 16 located in the lower part of the roof, also within the cavity of the glass unit filled with water. Both pipe sections 15 and 16 are made perforated for the input and output of water into the cavity (from the cavity) of the glass unit.

The height "h" of the posts 5 and 7 and the distance "b" between the posts are determined depending on a number of local conditions, incl. on the type of plants (vegetables) 17. In the upper part of the greenhouse cavity, small fans 18 can be located, blowing over the inner surface of the glass units to increase heat transfer.

The proposed design can be widely used for other premises in hot climates (various public buildings, cafes, etc.).

FIG. 2 and 3 introduced the following additional designations:

t _inside - air temperature inside the cavity;

t _soil - _soil temperature at a depth of zero amplitudes (i.e. at a depth of 10-20 m);

t _air - outside air temperature;

t _water - the temperature of the water in the glass unit;

"Sun" - solar radiation;

q ₁ - heat flow into the air chamber of the greenhouse due to solar radiation;

q ₂ - heat flow from the air chamber of the greenhouse into the water of the glass unit of the roof 3;

q ₃ - heat flow from the air chamber of the greenhouse into the ground;

q ₄ - heat flow from the outside air into the water of the glass unit;

q ₅ - heat flux into the water of the glass unit due to solar radiation.

A greenhouse for growing vegetables works as follows.

In the daytime (Fig. 2), the cavity of the greenhouse air chamber is heated by solar radiation (heat flow q ₁ ). In this case, part of the solar radiation (heat flux q ₅ ) is absorbed by the water of the glass unit, and part is generally reflected, therefore it is not indicated here. Excess heat from the chamber is discharged into the water of the glass unit (heat flow q ₂ ) and into the ground (heat flow q ₃ ). The water in the glass unit is also heated by the heat flow q ₄ from the outside air. The temperature t _{inside the} inside of the greenhouse cavity is set based on the rational temperature regime for growing vegetables (i.e. t _inside is the initial data). The temperature of the surface 1 with sufficient accuracy in a stationary mode can be taken equal to t _int . The water temperature in the cavity of the glass unit is calculated based on the assessment of the heat balance. A double-glazed window can be quite powerful (10 cm or more). Then the water is cooled at night by heat exchange with the outside air. But it is more efficient and reliable to equip a system for cooling water (see Fig. 1), which is connected to the cavity of the glass unit using perforated pipes 15 (inlet) and 16 (outlet). Then the thickness of the cavity can be about 1.0 cm, which makes the roof much lighter. Cold water is constantly pumped. Through the holes in the pipe 15, it enters the cavity of the glass unit, and the heated one enters the outlet pipes 16 through the holes in these pipes.

At night (Fig. 3), the water temperature in the glass unit t _water should be maintained by the cooling system equal to the air temperature in the cavity t _inside . In this case, the cooling system must compensate only for the effect of the heat flux q ₄ .

The calculation method is based on the following assumptions (Fig. 1, Fig. 2 and Fig. 3):

1) the air temperature in the greenhouse cavity in a stationary mode must be ensured equal to “t _int. »This temperature is set based on the most rational mode for growing plants;

2) the temperature on the ground surface in the stationary mode is equal to the air temperature in the greenhouse "t _int. ";

3) the air temperature outside the greenhouse is equal to “t _air. ".

4) water in the glass unit of the roof cuts off the thermal effect of the outside air “t” of the _air. "On the temperature in the cavity of the greenhouse, since the water is flowing, and the temperature of its" t _water "is regulated by the cooler and supplied through the pipe 15 to the glass units 3;

5) heat flow "q ₁ " enters the greenhouse cavity due to solar radiation "t of the _sun ". Excess heat is taken away by water (heat flux "q ₂ "). In addition, part of the heat goes into the ground (heat flux "q ₃ ") due to the temperature difference t _inside and t of the _ground at a depth of 10-20 m;

6) a stationary temperature regime (that is, constant in time) can be provided only with the equality "q ₁ ", on the one hand, and "q ₂ + q ₃ ", on the other. Thus, in the daytime (Fig. 2), the heating of the air in the greenhouse cavity is carried out by the heat flow and the selection of excess heat is carried out by the heat flow "q ₂ ". Heat flux "q ₃ " due to its smallness can be neglected. Thus, the water temperature should be less than the air temperature in the cavity: t _water <t _int . In this case, the water is heated due to the flows q ₂ , q ₄ , and q ₅ . This heat must be removed by the cooler.

Heat flow q ₁ is formed by heating by the sun. The resulting indicator is the radiation balance "Q" (kcal / (m ² ⋅ hour)), which is determined from climatological reference books for each region.

Part of the radiation balance goes to heating the surface 1 (Fig. 2) of the soil with an area F ₁ (m ² ):

q ₁ -k⋅Q⋅F ₁ , kcal / hour,

where k is a coefficient that determines the size of the part that goes to heat the soil surface.

Heat flow q ₂ is determined by the formula:

термическое сопротивление;Where

thermal resistance;

A is the heat transfer coefficient on the inner

roof surface, kcal / (m ² ⋅chas⋅grad);

F ₂ - roof surface area, m ² .

The heat flux q _{3 is} not taken into account (in reserve) due to its smallness.

Then, to ensure a steady state:

q ₁ = q ₂ ,

those. k⋅Q⋅F ₁ = (t _internal -t _water ) ⋅А⋅F ₂ ,

whence the water temperature required to ensure a stationary regime is

At night (Fig. 3), the outside air temperature (t _air ) can be higher than t _inside or below t _inside . Then this will cause a change in the temperature of the water, and after that the temperature of the water in the cavity will become equal to t of the _cavity , which will not be equal to t _int . In this case, the water must be provided with a temperature equal to t _internal .

In the daytime, the water will be heated (Fig. 2) due to heat flows q ₂ , q ₄ , q ₅ .

Heat flux q _{2 is} defined higher.

Heat flow q ₅ will be equal to:

q ₅ = Q⋅F ₁ ⋅ (1⋅k), kcal / hour.

Heat flow q ₄ will be equal to:

q ₄ = (t _air -t _water ) ⋅A ₁ ⋅F ₂ , kcal / hour,

where A ₁ is the heat transfer coefficient on the outer surface of the greenhouse roof.

At night, the water will be heated or cooled only by the heat flow q ₄ , and t _water will be equal to t _int .

The initial data for the calculation are:

1) sizes F ₁ and F ₂ (m ² ) - by 1 linear meter. m greenhouses;

2) radiation balance Q (kcal / (m ² ⋅hour));

3) air temperature t _air (° С);

4) the required air temperature in the greenhouse cavity t _inside (° С);

5) heat transfer coefficient A (kcal / (m ² ⋅ hour⋅grad));

6) heat transfer coefficient A1 (kcal / (m ² ⋅ hour⋅grad));

7) coefficient k (b / r).

Dimensions F ₁ and F ₂ are taken in accordance with the design data. Radiation balance Q, air temperature are taken according to climatological reference books. Coefficient A is taken equal to 7.5 with stationary air and equal to 20.0 - when the roof is blown with a small fan from the inside (item 18 in Fig. 1). Coefficient А _{1 is} taken equal to 20, coefficient k - according to experimental data.

The result of the calculation is the water temperature t _water , which provides the required temperature in the greenhouse cavity t _int .

This invention is based on the solution of the following technical contradiction:

on the one hand, the roof must be transparent in order to transmit light, on the other, it must not transmit light so as not to overheat the cavity.

The solution to the technical contradiction is the use of a layer of water in the composition of the roof, structurally made in the form of double-glazed windows filled with water. Water is transparent and transmits light, but at the same time it perceives excess heat from the cavity.

The first significant feature of this technical solution is a closed air chamber located on the natural ground surface and bounded from the sides and ends by external walls, and from above by a transparent convex roof upwards.

The second essential feature of this technical solution is the presence of a device for lowering the air temperature within the air chamber.

The third significant feature of this technical solution is that the device for lowering the air temperature and the roof are combined and made in the form of a double-glazed unit of two parallel (equidistant) glasses with a cavity between them filled with water.

The fourth essential feature of this technical solution is that the greenhouse is equipped with a water cooler connected to the cavity of the glass unit of the roof with supply and discharge pipes, which contain end sections within the roof, and the end section of the supply pipe is located on the ridge of the convex roof, and the end section of the outlet pipe located in the lower part of the roof, while the end sections of the pipes are perforated and located within the cavity of the glass unit.

All four main essential features are interrelated, necessary and sufficient to achieve the claimed technical result. All these features are reflected in clause 1 of the formula.

The fifth additional essential feature of this technical solution is that the greenhouse is made of a series of adjacent sections with autonomous roofs and common internal walls made of separate posts united by a common crossbar.

The fifth essential feature is reflected in the second paragraph of the formula.

The effectiveness of the proposed technical solution lies in the fact that it is possible to ensure the normal temperature regime of the air chamber in hot climates, using the entire daylight hours without artificial shading.

Claims (2)

1. A greenhouse for growing vegetables, including a closed air chamber located on the natural surface of the soil and bounded from the sides and ends by external walls, and from above by a transparent convex roof upward, and equipped with a device for lowering the air temperature within the chamber, characterized in that the device for lowering the air temperature and the roof are combined and made in the form of a double-glazed unit of two parallel glasses with a cavity between them filled with water, and the greenhouse is equipped with a water cooler connected to the cavity of the glass unit of the roof with supply and discharge pipes, which contain end sections within the roof, and the end section the supply pipe is located on the ridge of the upwardly convex roof, and the end section of the discharge pipe is located in the lower part of the roof, while the end sections of the pipes are made perforated and are located within the cavity of the glass unit. 2. A greenhouse for growing vegetables according to claim 1, characterized in that it is made of a series of adjacent sections with autonomous roofs and common internal walls made of separate racks united by a common crossbar.

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