SOLAR HEAT ACCUMULATING GREENHOUSES

Abstract: A solar heat accumulating greenhouse has a heat accu­ mulating tank (5B) buried in the ground within the green­ house, an air discharge pipe (504) open towards the lower portion in the greenhouse and an air suction pipe (505) open towards the upper portion of the greenhouse having an air circulating fan (506) on the way. A large number of air blast pipes (521) extending through a cover (502) of heat conduct­ ing material are buried in the ground. Since the plant culture soil is thereby heated simultaneously with the air within the greenhouse, growth of plants is expedited.

Description: SOLAR HEAT ACCUMULATING GREENHOUSES This invention relates to solar heat accumulating greenhouses. Conventionally, in greenhouses such as shown in Japanese Patent Kokai 54-91444, double roofs constructed with two glass panes, solar heat receiving panels arranged in the double roofs, a water storage tank storing hot water from the panels and an air conditioner using the hot water from the tank are provided. In another example as shown in Japanese Utility Model Kokai 55-56570, a heat collector and a heat accumulating tank connected to the heat collector via a fan are provided. The former has the disadvantage that the double roof is necessary for arranging panels having wide heat receiving area near the roof of the greenhouse, and is thus costly to manufacture. In both of them only the air in the greenhouse is warmed, not the soil itself directly. According to the present invention there is provided a solar heat accumulating greenhouse having a heat accumulating tank buried in the ground within the greenhouse, an air discharge pipe open towards the lower portion in the greenhouse and an air suction pipe open towards the upper portion of the greenhouse having an air circulating fan on the way; characterised in that a large number of air blast pipes extending through a cover of heat conducting material are buried in the ground. In this greenhouse, during sun shining hours in the day time, an extremely high heat collecting efficiency is achieved so as to accumulate extra heat, which may be discharged during night time or in rainy weather, and therefore, the temperature within the greenhouse can be maintained at a required level, without employment of other heating facilities and therefore avoiding fuel cost and thus contributing to energy saving and saving of expense. Particularly, since the plant culture soil is also heated simultaneously with the air within the greenhouse, growth of plants may be expedited still further as compared with greenhouses conventionally proposed. For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example,to the accompanying drawings in which: Figure l is a front view, partly broken away, of a solar heat accumulating greenhouse, and Figure 2 is a front view in section showing, on an enlarged scale, part of the greenhouse of Figure 1. The greenhouse 5A has,buried in the ground within the greenhouse 5A, a latent heat accumulating tank 5B including a heat insulating box-like member 501 having a corrosion-resistance surface, and a cover member 502 made, for example, of a metallic material having superior corrosion resistance and heat conduction applied on the upper surface of the box-like member 501. The cover member 502 is provided with a large number of blast pipes 52i extending upwardly from the cover member 502, each of which blast pipes 521 is further covered by a hood member 522 having a plurality of through holes 522a directed in a horizontal direction as is most clearly seen in Figure 2. The cover member 502 is provided with a plurality of shallow water discharge grooves 523 arranged in parallel relation to each other. The interior of the latent heat accumulating tank 5B is partitioned into a plurality of sections 5B1, sub2 , and 5B by partition members 503 n of a coarse mesh-like structure. In the latent heat accumulating tank 5B a large number of heat accumulating members 5S each being a capsule, for example, of a spherical shape or tetrapod-like configuration, or being a spherical container or capsule of any other desired shape, having a heat conducting body with a fill of latent heat accumulating substance, are accommodated under the state where a large amount of gaps are provided therebetween. To the latent heat accumulating tank 5B an air discharge pipe 504 open towards the lower portion in the greenhouse 5A and an air suction pipe 505 open at the upper central portion in the greenhouse are connected in a symmetrical relation with each other. At the lower portion on the way of the air suction pipe 505, there is provided an air circulating fan 506. At the south side outside the greenhouse, an air collector 5C made of glass or metallic material having sufficient solar heat absorbing ability and corrosion resistance is installed, and is connected, as a by-pass, to the upstream side suction pipe 505 along the air flow of the air circulating fan 506. In the course of the suction pipe 505 and an air collector lead-in pipe 507, air plugs 505a and 507a are respectively inserted for change-over of the air passage. The upper portion of the latent heat accumulating tank 5B is covered by plant culture soil 508 to such an extent as the blast pipe hoods 522 are buried therein. For the culture soil provided around the blast pipe hoods 522, soil of coarse particles is particularly employed so that the soil may not enter the interior of the hoods via the throughholes 522a of the hoods 522. In the plant culture soil 508, plants 5D are raised. By the above arrangement, during sun shining hours in the day time, heated air in the greenhouse is led into the air collector Sc through the suction pipe 505, and is further heated by the solar heat in the tank. The warm air is then drawn by the air circulating fan 506 into the latent heat accumulating tank 5B for heat accumulation in the heat accumulating substance 5S in the tank, and is blasted into the greenhouse through the air discharge pipe 504, with heat inertia still contained therein. Meanwhile, part of the warm air is pushed out of the blast pipes 521 for penetration into the culture soil so as to warm up side soil so as to expedite the growth of the plants. During night time and rainy weather, the air valve 505a at the side of the suction pipe is opened, and the air valve 507a at the side of the air collector is closed as to form the air circulating system between the interior of the greenhouse and the latent heat accumulating tank 5B, and thus, the air within the greenhouse drawn in from the air suction pipe 505 is introudced into the latent heat accumulating tank 5B to be heated, in the tank, by receiving the heat radiating action of the heat accumulating members 5S, and is discharged into the greenhouse and the soil for heating in the similar manner as in the day time. The heat radiation into the culture soil 508 may also be effected through the heat conduction by the cover member 502. The water discharge grooves 523 are arranged to collect surplus water for discharging it out of the greenhouse during irrigation. By the above arrangement, there is no possibility that water enters from the blast pipes 521 into the heat accumulating tank 5B. The fill of latent heat accumulating substance in the heat accumulating members 5S can be CaCl26H2O; Na2SO4 10H2O; Na2SO3 5H2O; paraffin etc.

Claims: CLAIMS 1. A solar heat accumulating greenhouse having a heat accumulating tank (5B) buried in the ground within the greenhouse, an air discharge pipe (504) open towards the lower portion in the greenhouse and an air suction pipe (505) open towards the upper portion of the greenhouse having an air circulating fan (506) on the way; characterised in that a large number of air blast pipes (521) extending through a cover (502) of heat conducting material are buried in the ground. 2. A solar heat accumulating greenhouse as claimed in claim 1, wherein the heat accumulating tank (5B) has a large number of heat accumulating members 5S each comprising a heat conducting substance and a filling of latent heat accumulating substance in the interior thereof, a large amount of gaps being provided between these members. 3. A solar heat accumulating greenhouse as cla med in claim 1 or 2, wherein each air blast pipe (521) is covered by a hood member (522) buried in the ground and having a plurality of through-holes (522a) directed in a horizontal direction.

Inventors: ITO, HAJIME, YANO, NAOMICHI
Applicants: KUBOTA LTD.
Application year: 1982
Main classification: F24J2
IPC codes: A01G7, A01G9, F28D20, F24D11, F24J2