Combined solar liquid and gaseous heat-transfer agent heater

The invention relates to heliotechnics, namely to devices for converting solar energy into thermal energy and can be used to supply the industrial and domestic use technique with hot and heated water.

An air-water preheater is known, which carries out the passage of the different thermal agents (liquids and gases - water, air) on the same path from the account of the change from one thermal agent to another. The device indicated contains a metal housing, in which a mixed-use manifold is located in the form of a sinusoidal metal pipe with inlet and outlet ports for advancing the thermal agent. The device case is hermetically sealed with a transparent cover. As a heat accumulator, a о two-layer structure is used, in which the lower layer is made of gravel, and the upper layer - of sand. Air or water passes through the metal pipe, located on the surface of the heat accumulator and partially submerged in its layer of sand. At the entrance of the pipe is installed a valve for changing the heat agent [1].

The disadvantage of this device is the comparatively low efficiency, conditioned by the possibility of concomitant heating only of a thermal agent, which not only increases the duration of the process, but also decreases the efficiency of the air-water preheater.

Also known is a combined solar air / water collector, which contains a rectangular parallelepiped body with a transparent cap installed on it and with a heat-insulated bottom, an absorber located inside the body, which consists of a row of parallel pipes placed with each other play, fixed with the possibility of flow in them of the fluid thermal agent in the ports of the terminal collectors, one of them having a connection for the intake of the cold liquid thermal agent, and the other - with a connection for the evacuation of the heated liquid thermal agent, at the same time the pipes are parallel to the heater cap. In the absorber are provided two rows of parallel pipes, placed one below the other and joined by means of a means that ensures the thermal transfer between them. The pipes of a row are provided for the passage of the fluid thermal agent, and the pipes of the second row for the passage of the gaseous thermal agent. The pipes of each row are fixed in the corresponding manifolds. The light reflecting layer, located at the body, creates thermal convective fluxes that heat the absorber pipes [2].

The disadvantages of this collector are that it is complicated after construction, it is uncomfortable for assembly and installation, it has considerable weight, it is insufficiently energy efficient and it is an expensive device.

The problem solved by the invention is to design a simple and effective device from a constructive point of view with the use of accessible and inexpensive materials, to ensure the separate or simultaneous heating of liquid and gaseous thermal agents, in particular water and air, and comfortable in operation.

The device according to the invention removes the disadvantages mentioned above in that it contains a rectangular parallelepiped body with a transparent lid installed on it and with a thermally insulated bottom, an absorber located inside the body, which consists of a series of parallel pipes, placed with each other playfully, fixed with the possibility to flow into them the liquid thermal agent from the terminal collectors, one of them being equipped with a connection for the flow of the cold liquid thermal agent, and the other - with a connection for the discharge of the heated liquid thermal agent, the pipes being placed parallel to the lid. The walls of the heater body are made cavities, the cavities of three of them are united with the possibility of circulation of the gaseous thermal agent, and the cavity of the fourth wall is divided by a horizontal dividing wall of a whole into two channels. The upper channel cavity is joined to the adjacent wall cavities and the lower channel cavity is closed, with a thermal insulation layer on the outer wall and a connection for the exhaust of the heated gaseous thermal agent. In the upper part of the inner walls, up to the absorber, holes are made, and in the lower part of the outer wall of one of the three side walls! an orifice is executed for the flow in the communicating cavities of the cold gaseous thermal agent. The absorber pipes are located practically parallel to the side wall with two channels. The outer surface of the absorber pipes is covered with light absorbent material. At the bottom of the body between the opposite side walls, perpendicular to the absorber pipes, are installed with the possibility of placing on them at least two elongated support elements, practically parallel to each other, in the form of three-dimensional hollow geometric figures, with holes pierced in the lateral faces for circulation. of the gaseous thermal agent. The front ends of the supporting elements on one side are executed closed, and on the other side - open and conjugated with the holes executed for fixing them in the inner wall of the lower channel of the fourth side wall. The absorber pipes are oval in shape and are located at an angle of 10 ... 20? compared to the body cover. The absorber pipes are rectangular in shape and are located parallel to the body cover. The absorber pipes are located at the level of the horizontal partition wall of the fourth side wall. The side walls are made of heat-insulating material. The absorber pipes are made of metal, polymeric materials or composites. As a heat-absorbing material for the absorber pipes, black matte paint is used. The cross-section of the support elements has a triangular, rectangular or trapezoidal shape.

The result of the claimed invention consists in improving the operating conditions, reducing the heat losses of the heater, as well as enhancing the safety and simplifying the construction.

MD 135 Y 2010.01.31

Coating the absorber pipes with heat absorbing material, which accumulates the thermal energy of the solar radiation, ensures the direct heating of the liquid passing through them.

The cold air, penetrating into the communicating cavity walls, spreads on the perimeter of the body and, passing through the holes in the inner walls inside the body, envelops with a uniform flow the pipes of the absorber heating from them.

At the same time, the heated air, which passes into the body below the absorber, through the holes through the support elements, fixed in the holes in one of the interior walls conjugated with their front ends, penetrates into the closed insulated channel formed in the given wall and then continues. deliver to the consumer.

As a result, in the proposed device, the thermal energy is practically spent only for heating the thermal agents, which essentially increases its efficiency from reducing heat losses to the minimum.

To achieve the given effect also contributes the execution of the bottom and the walls of the body of thermal insulation material, and in the case of the use of the oval-shaped pipes - their placement at an angle of 10 ... 20 ° to the body lid, which corresponds to the optimal position of the surface that it is warmed by the incident sunlight during daylight.

The traditional positioning of the pipes of the parallel absorber with the walls of the heater and their placement on the elongated support elements caves, installed at the bottom of the body perpendicular to the axis of the pipes, ensures the construction of the device stability and safety in operation.

The standardized geometrical shape of the cavity support elements (triangular, rectangular or trapezoidal), the front ends closed on one side and open on the other, form channels that ensure the passage of the heated air flow in the required direction and make these elements convenient in preparation and assembly.

The use of accessible and inexpensive elements to make the absorber pipes, the heater body and the support elements conditions the low price of the device as a whole.

Thus, the introduction of the new elements allows to reach high operating conditions for simple and constructively safe solar heaters that ensure the simultaneous heating of liquid and gaseous thermal agents.

The invention is explained by the drawings in FIG. 1-3, which represents:

FIG. 1, the cross section of the combined solar heater;

FIG. 2, the longitudinal section of the combined solar heater;

FIG. 3, top view of the combined solar heater absorber.

The device confines a body 1 in the form of a rectangular parallelepiped with a thermal insulated bottom 2 and the side walls of the cavities 3, cavities 4 which, created by the outer and inner walls, form channels for moving cold air masses. The cavity of one of the side walls is divided by a horizontal partition wall of a whole 5 into two parts, which forms an upper channel 6 for moving cold air and a lower channel 7 for moving heated air. At the same time, the cavity of the lower channel 7 is closed, with a thermal insulation layer 8 on the outer wall and with a connection for the evacuation of the heated gaseous thermal agent (shown in the figure). The cavities 4 of the three side walls 3 and the upper channel 6 of the fourth wall communicate with each other.

The heater body 1 is closed with a transparent cover 9, which seals tightly to the front ends of the side walls 3.

Inside the body is located an absorber 10, which consists of a series of parallel pipes 11, placed with each other playfully and fixed with the possibility to flow into them the liquid thermal agent from the terminal collectors 12 and 13 (figs. 2, 3 ). The manifold 12 is provided with a connection 14 for the flow of the cold liquid thermal agent. The manifold 13 is provided with a connection 15 for the evacuation of the heated liquid thermal agent.

In the upper part of the inner walls 19, up to the absorber 10, the holes 16 are executed, and in the lower part of the outer wall of one of the three side walls an hole is executed for the flow in the communicating cavities 4 of the cold gas thermal agent (in the figures not shown).

At the bottom 2 of the body between the opposite side walls 3, perpendicular to the pipes 11 of the absorber 10, are installed with the possibility of placing on them of the pipes 11 at least two elongated support elements 17, practically parallel to each other, in the form of three-dimensional hollow geometric figures, with holes 18 in the lateral faces for the circulation of the gaseous thermal agent. The front ends of the support elements 17 on one side are executed closed, and on the other side - open and conjugated with the holes executed for their fixing of the fourth side wall (in the figures not shown), in the inner wall 19 of of the lower channel 7.

In the assembly process of the device claimed at the bottom 2 of the body, the supporting elements 17, which are from one side wall to the other, are located at a distance equal to and parallel to one another. The ends of the pipes 11 are fixed in the corresponding holes of the collectors 12 and 13, forming о rigid construction, which are installed on the support elements 17. In the body 1 there are provided technological gaps for fixing the protruding ends of the collectors and holes for the location of the connections 14 and 15. Above the body is fixed the transparent cover 9, through which the solar radiation enters the absorber 10.

MD 135 Y 2010.01.31

Various embodiments of the invention can be obtained by arbitrarily joining such parts forming the proposed construction, such as pipes and supporting elements, namely - as pipes of the absorber can be used pipes of oval or rectangular shape, and as supporting elements - articles, the cross-section of which may have a triangular, rectangular or trapezoidal shape.

The described constructive solution of the solar heater combined with liquid and gaseous thermal agents determines the following possible firing modes:

- heating only water;

- heating only the air;

- concurrent heating of water and air.

When heating only the water, the heater does not supply air and the walls of the body 3 of the body 1 serve as thermal insulation. The water enters through the connection 14 and the manifold 12 in the pipes 11 of the absorber 10. The walls of the pipes 11 of the absorber 10, oriented towards the transparent cover 9, are heated by the solar rays and transfer the heat of the water flowing through these pipes. The heated water is transported through the collector 13 and the connection 15 in the hot water insulated pipe for its subsequent use.

When heating only the air, the heater is not supplied with water, and the air activated by the fan, through the hole in the lower part of the outer wall of one of the three side walls 3 penetrates into the communicating cavities 4, including in the channel 6 of the the fourth side wall. From the cavities 4 the air passes through the holes 16 inside the body and heats up passing the pipes 11 of the absorber 10, heated by the sun's rays.

further the heated air flows through the holes 18 inside the support elements 17 and, under the action of the air masses that penetrate continuously through holes in the inner wall 19, it moves into the insulated channel 7, from which through the exhaust connection it goes into the air duct. and to consumers.

At the simultaneous heating of the liquid and gaseous thermal agents the corresponding connections are supplied with water and air, and the heating processes take place in parallel.

In terms of the flow of each of the thermal agents and the intensity of the solar radiation, certain temperatures of water and air are reached when leaving the collector. If in the composition of the solar heating system flow regulators of thermal agents and temperature sensors are introduced, then by changing the flow rates can be ensured the heating of each of the thermal agents to the prescribed level.

Research has shown that, depending on the intensity of the solar radiation, due to the proposed construction of the solar heater combined with liquid and gaseous thermal agents, it can be obtained heated water up to 3O ... 5O ° C and heated air up to 40 ... 50 ° C.

Example of concrete implementation

In the process of designing the claimed technical solution, an experimental model of the solar heater combined with liquid and gaseous thermal agents was made, which had a rectangular parallelepiped shape.

Heater dimensions:

base surface - 2 m², height of side walls - 0,15 m, width of opposite side walls of one pair - 1 m, width of opposite side walls of another pair -2 m, width of cavities of side walls 0,03 m.

The side walls were made of low conductive waterproof plywood of type OSB3. The body lid was made of cellular polycarbonate with a thickness of 8 mm. As a thermal insulation material for the bottom and the exhaust air duct, expanded polyethylene (IZOLON) with a thickness of 6 mm was used.

The pipes of the absorber in 16 pieces, having in section oval shape and the ratio of axes of 1: 6, were installed at an angle of 15 ° to the lid and fixed in the rectangular shaped manifold at a distance of 0.015 m from the lid. The pipes were made of black polyethylene with a wall thickness of 1.6 mm.

The support elements were made of plywood with a thickness of 4 mm and had a triangular cross-section with side dimensions of 0.08 m.

Rainwater was used as a liquid thermal agent, and as a gaseous water - air.

During the work process, the heater is supplied with water by free flowing from the tank with flow control by means of a holy valve, and the air is pumped by means of a fan В12.

During sunny weather and at a water flow of 0.01 1 / s the water in this device is heated to a temperature of 50 ° C and the air at a flow of 0.005 m³/ s up to 70 ° C.

Usually, these heaters are installed in a sector that is under the sun from 8 to 17 hours.

MD 135 Y 2010.01.31