RU2023383C1 - Device for storing farm products - Google Patents

Abstract

FIELD: storage of agricultural products. SUBSTANCE: device has chamber with heat-insulated cover, chamber cooling arrangement made in form of heat pipes laid into chamber through ground, and removable heat insulation. Heat pipes have liquid-filled housings with volume change compensators made in form of flexible diaphragms and low heat transfer inserts placed inside heat pipes at ground-to-atmosphere border. EFFECT: enhanced quality of storing of farm products. 1 tbl, 2 dwg

Description

 The invention relates to agricultural machinery, namely to the storage of agricultural products.

 A device for storing agricultural products, including a chamber for products with a ventilation system and a casing filled with water, is known.

 The known device due to convection of water in the casing allows to achieve a relative uniformity of the temperature distribution over the chamber, however, it does not contain cooling means capable of accumulating cold in the device.

 This disadvantage is partially eliminated in the device for storing agricultural products, containing a chamber placed in the ground with a heat-insulated lid, a chamber cooling means made in the form of heat pipes passing from the atmosphere through the ground into the chamber, and removable thermal insulation.

 The disadvantage of this device is the relatively small amount of accumulated cold, since in this case the cold accumulates in the soil through which the heat pipes pass, and the soil has insufficient specific cold storage. In addition, continuous high-conductivity heat pipes facilitate the penetration of heat into the food chamber in the summer, which reduces the stability of the storage temperature.

 The aim of the invention is to increase the amount of cold accumulated by the season and the duration of storage by using the liquid-ice phase transition and increasing the storage temperature stability.

 The goal is achieved in that in a device including a chamber with a thermally insulated lid, cooling means in the form of heat pipes passing from the atmosphere through the soil into the chamber, and removable heat insulation, heat pipes are equipped with liquid-filled casings with expansion joints made in the form of flexible membranes, as well as low heat conducting pipe inserts at the soil – atmosphere interface.

 It is known to supply a food chamber with a casing filled with water. It is also known to use heat pipes passing from the atmosphere through the soil into the food chamber to seasonal freeze the soil around it. A significant difference of the proposed device is the supply of heat pipes with liquid-filled casings with compensators for volume changes made in the form of flexible membranes, as well as low heat conductive pipe inserts at the soil – atmosphere interface. The use of this combination of distinctive features is unknown.

 The first device has a rather cold-consuming storage medium - water in the casing and does not contain an effective cooling means that allows you to turn water into ice. The second device has an effective means of cooling - heat pipes and insufficient cold storage medium - soil. The proposed device makes it possible to accumulate cold in the soil and use the liquid-ice phase transition for this, and thus obtain a greater effect than the sum of the effects of using the known devices separately.

 In FIG. 1 schematically shows a device, a cross section; in FIG. 2 is a top view in section.

 A device for storing agricultural products consists of a chamber 1 for products located in the soil 2, a thermally insulated cover 3, heat pipes 4 partially filled with coolant 5 (ether, alcohol, ammonia, etc.), with evaporation zones 6 and condensation 7, finning 8 low heat-conducting pipe inserts 9 (carpet, milchior, etc.), casings 10 with compensators for volume changes in the form of flexible membranes 11 filled with liquid 12, for example, water or other. The chamber 1 is separated from the casings 10 by removable thermal insulation 13.

 The device operates as follows.

 In winter, removable thermal insulation 13 was dismantled. The condensation zones 7 of the heat pipes are washed by cold atmospheric air, as a result of which they are kept cold, and the evaporation zones 6 are kept warm due to the heat of the soil 2. The heat carrier 5 evaporates in zone 6, taking heat from the liquid 12 and soil, rises to zone 7, where it condenses, giving this heat to the atmosphere, and flows by gravity into the evaporation zone. Thus, the circulation circuits in the heat pipes are closed. As a result of the operation of the heat pipes, the liquid 12 passes into the solid state by phase transformation, the change in the volume of the casing 10 is compensated by the deflection of the flexible membranes 11 surrounding the heat pipes, the soil is also frozen, and a large amount of cold accumulates around the chamber 1.

 At the end of winter, when the average air temperature rises, removable thermal insulation 13 is installed. Due to this, the losses of accumulated cold are reduced. Before loading the chamber, part of the insulation 13 is dismantled depending on the required storage temperature of the products. In the summer period, zones 7 of the heat pipes have a temperature higher than zones 6, as a result of which the circulation of the heat carrier 5 stops. The excess heat from the chamber 1 is gradually spent on defrosting the soil and melting the frozen liquid 12. The penetration of heat from the atmosphere into the soil and the cold accumulators through the casing of the heat pipes is impeded by low-heat pipe inserts 9. Thus, the required temperature is stably maintained in the chamber 1.

 Providing heat pipes with liquid-filled casings allows one to accumulate cold not only in soil with a relatively low cold-resistance, but also to use a liquid-ice phase transition for this, which increases the accumulated cold supply and storage time and thereby improves storage temperature stability. Compensators of volume changes make it possible to compensate for a change in the volume of casings during a phase transition and thus carry out phase transitions of a liquid without violating the integrity of the structure.

 The supply of heat pipes with low-conductivity inserts at the soil – atmosphere boundary prevents the leakage of cold from the soil and casings into the atmosphere through the body of the heat pipes and thus increases the storage temperature stability.

PRI me R. Accept: the dimensions of the chamber for products 10x10x1 m ³ , the number of heat pipes N = 80 pcs, the heat output of one heat pipe W = 500 W, the cross-section of the casings of the heat pipes 0.5x1 m ² , the total volume of casings V = 130 m ³ , the contact surface S casings with soil 350 m ² ; contact surface S ^{I of} casings with removable thermal insulation 260 m ² ; filling the casings liquid - the water with a freezing point of ⁰ ° C, _a heat of freezing τ = 300 ˙ March ¹⁰ J / kg = 29.7 ˙ October ⁷ J / m ³ and the specific heat _C ˙ = 4.19 10 ⁶ J / m ³ K, the thickness of removable thermal insulation δ = 0.1 m made of foam with a coefficient of thermal conductivity λ = 0.2 W / m ˙ K, the heat capacity of the soil C _gr = 2.09 ˙ 10 ⁶ J / m ³ K, the thermal conductivity of the soil λ _gr = 0.81 W / micron, soil freezing heat r _g = 6.3 ˙ 10 ⁷ J / m ³ , the temperature gradient in the soil g _g = 5 K / m, the volume of the cooled soil V _g = 330 m ³ , the heat capacity of the product C _n = 2,47x10 ⁶ J / m ³ K, the temperature difference and to products Ukhov Δ T = 5 ° ^C.

The amount of cold accumulated during the winter for the proposed device
Q = Q _og + Q _sg + Q _ov + Q _sv = 3.4 ˙ 10 ⁹ +20.8 ˙ 10 ⁹ +2.72 ˙ 10 ⁹ +38.61 ˙ 10 ⁹ = 65.53 ˙ 10 ⁹ J ,
wherein Q _og = V ˙ C _c T _c = 330 ˙Δ 2.09 ˙ ˙ June ¹⁰ x 5 = 3,4 ˙ September ¹⁰ J - cold accumulated in chilled 5 to 0 ^C. the ground; Q _zg = V _gr ˙ r _gr = 330 ˙ 6.3 ˙ 10 ⁷ = 20.8 ˙ 10 ⁹ J - accumulated cold of frozen soil; Q _ov = V ˙C _in ˙Δ Т = 130 ˙ 4.19 ˙ 10 ⁶ x 5 = 2.72 ˙ 10 ⁹ J - cold accumulated in water cooled from 5 to 0 ^о С; Q _sv = V ˙ r _in = 130 ˙ 29.7 ˙ 10 ⁷ = 38.61 ˙ 10 ⁹ J - cold accumulated in frozen water.

=

= 18,8 сут.The required time of accumulation of cold in the winter for the proposed device
t _a =

=

= 18.8 days

=

= где Q_n= 100 ˙ 2,47 ˙ 10⁶ ˙ 20^оС=4,94 ˙ 10⁹ Дж - холод, необходимый для охлаждения продукта до температуры хранения.The duration of storage of the product for the proposed device (the time during which it is maintained in the chamber no more than 5 ^° C)

=

= where Q _n = 100 ˙ 2.47 ˙ 10 ⁶ ˙ 20 ^о С = 4.94 ˙ 10 ⁹ J is the cold required to cool the product to storage temperature.

The amount of cold accumulated during the winter for the prototype
Q '= Q _og + Q _sg + Q _ov = 3.4 ˙10 ⁹ +
+ 20.8 ˙ 10 ⁹ + 2.72 ˙ 10 ⁹ = 26.92 ˙ 10 ⁹ J.

=

=

= 7,78 сут.The necessary time for accumulating cold in the winter for the prototype
t

=

=

= 7.78 days

=

=
Преимущество предлагаемого решения по сравнению с известными подтверждается данными, приведенными в таблице.Duration of product storage for prototype

=

=
The advantage of the proposed solution in comparison with the known is confirmed by the data given in the table.

Number and duration of the cold accumulated by storing the product at a temperature not exceeding 5 ^{° C} solution of the present embodiment in comparison with sharing distinguishing features over known devices respectively 2.43 and 2.71 times.

Claims (1)

 A DEVICE FOR STORING AGRICULTURAL PRODUCTS, comprising a chamber with a thermally insulated lid, means for cooling the chamber, made in the form of heat pipes passing from the atmosphere through the soil into the chamber, and removable heat insulation, characterized in that the heat pipes are equipped with liquid-filled casings with compensators for volume changes, made in the form of flexible membranes, and low-heat-conducting inserts placed in heat pipes at the soil – atmosphere interface.

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