RU2350853C2 - Domestic solar water heater - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: domestic solar water heater is made in the form of triangular prism the volume whereof represents water storage tank, and an inclined prism face made of plate metal coated with black mat paint, and having plate-glass coating, is heat-receiving surface (heat collector). Besides inside storage tank, parallel to heat-receiving surface there installed is special dividing panel used as deflector and made of rigid heat-insulating material (e.g. solid-foamed material). Dividing panel is adjacent to side (triangular) faces of the tank and has gaps with other surfaces in order to provide convection flows. All water storage tank surfaces, except heat-receiving surface, have heat-insulation. On one of the storage tank faces there fixed are branch pipes used for supplying cold water and discharging hot water. At that hot water discharge branch pipe is located at the same level or a bit higher than upper edge of dividing panel, by means of which convection water cooling is restricted.

EFFECT: invention provides improvement of service and application performance (packaged design, easy manufacturing, erection and operation, and low cost), and effective use of solar radiation energy by decreasing heat losses during cloudy weather and at night.

1 dwg

Description

The invention relates to the field of use of solar energy, in particular to devices for converting the energy of light radiation into heat, and is intended to produce hot water for domestic use using solar radiation.

A typical design of an industrial solar water heater (www.Mensh.ru. "Solar water heater designs", Fig. 3), consisting of an inclined glazed heat collector, a separate, well insulated, water storage tank and heat-insulated pipes connecting these elements, is adopted . The bottom of the battery tank is at least 300 mm above the top of the collector. This arrangement eliminates the cost of additional energy for the circulation of water in the system. Circulation occurs only due to natural convection. When heated, the water in the collector expands, becomes less dense, rises up the collector and through the pipe enters the upper part of the storage tank. As a result, cooler water at the bottom of the tank is forced out and flows through another pipe to the lower part of the collector. This water, in turn, is heated and rises into the tank. While the sun is shining, water will constantly circulate along this circuit, becoming more and more heated. Due to the fact that the tank is raised above the collector, the effect of overturning circulation as a result of nightly cooling of the coolant in the collector is nullified, since cold water simply accumulates at the lower point of the system (at the bottom of the collector), while warm water remains in the buck.

Such a system has the following disadvantages:

- sophisticated manufacturing technology of sealed thermal collector;

- manufacture of a separate battery tank with good thermal insulation;

- the manufacture of special load-bearing structures for installing the heat collector at a certain angle to the horizon and the storage tank above the heat collector;

- the need for design and installation work with reference to specific operating conditions and customer requirements, which can only be performed by specialists.

Signs of an analogue common with the proposed design of a domestic solar water heater (BSVN) are as follows:

- flat glazed thermal collector;

- water storage tank with thermal insulation.

The known design of a solar water heater, adopted for the prototype [www.Mensh.ru. "Designs of solar water heaters", Fig. 2], in which the heat collector is placed in a flat metal container, painted black and coated with sheet glass. On one side, the container has a protruding water tank. The deflector inside the container provides thermosiphon circulation, as a result of which heated water from the collector compartment enters the battery compartment, and cold water from the bottom of this compartment enters the collector. The battery compartment heats up during the day and is thermally insulated at night to reduce heat loss.

The disadvantages of the prototype are:

- a significant decrease in the effectiveness of its use in the middle and high latitudes due to the need to use it in a horizontal position;

- Significant heat loss in cloudy weather and at night;

- inconvenience of operation, which consists in the fact that in order to maintain hot water on the heat collector in the evening, it is necessary to install external thermal insulation and remove it in the morning.

The features of the prototype, common with the proposed design of a domestic solar water heater (BSVN), are as follows:

- flat thermal collector;

- a coating of sheet glass;

- water storage tank;

- deflector (dividing panel) inside the heat collector;

- nozzles for supplying cold water and draining hot water.

The technical result achieved in the proposed design of the BSVN is to increase the efficiency of its use in the middle and high latitudes due to the location of the heat collector at an optimal angle (close to the geographical latitude of the area), to reduce heat loss in cloudy weather and at night, and to eliminate the need use of temporary thermal insulation.

This is achieved by the fact that the domestic solar water heater is made in the form of a trihedral prism, the volume of which is a water storage tank, and the heat collector is an inclined face made of sheet metal coated with matt black paint and having a sheet of glass coating, in addition, inside the tank -accumulator, parallel to the heat collector, a special separation panel is installed that plays the role of a deflector and is made of rigid heat-insulating material (for example, rigid foam). The separation panel is adjacent to the side (triangular) sides of the tank and has gaps with other surfaces to provide convective flows. On one of the faces of the storage tank are fixed pipes for supplying cold and draining hot water. In this case, the pipe for draining hot water is located at the same level or slightly higher than the upper edge of the separation panel, which limits the convective cooling of the water. All surfaces of the water storage tank, except for the heat collector, are insulated.

In cloudy weather and at night in such structures, intense cooling of water occurs due to reverse convection. In the proposed design, this process is significantly limited, since when cooling the water level decreases and when it reaches the upper edge of the separation panel, convective processes cease. At the same time, the heat-insulating material from which the separation panel is made practically eliminates diffuse cooling of the bulk of the water (except for that which is located in a limited space between the separation and heat-receiving panels of the BSVN).

Distinctive features that determine the conformity of the proposed design BSVN to the criterion of "novelty", the following:

- manufacture of a water storage tank in the form of a trihedral prism;

- the use of a large facet of the prism as a thermal collector;

- manufacture of a dividing panel (deflector) from a rigid heat-insulating material;

- thermal insulation of all surfaces except the heat collector;

- the location of the pipe for draining hot water at the level of the upper edge of the separation panel.

To prove the conformity of the proposed design BSVN to the criterion of "inventive step" was analyzed the whole set of features and separately distinguishing features. It was found that the use of the above distinctive features, which, together with the known features, give a technical result consisting in improving operational and consumer properties (compactness, ease of manufacture, installation and operation), was not found in literary sources. Thus, according to the authors, the proposed design BSVN meets the criterion of "inventive step".

The proposed design BSVN (see figure 1) consists of a storage tank 1 in the form of a trihedral prism, a large side face 2 of which is a heat-receiving surface, and the necessary structural rigidity is given by a power frame made of metal corners 3. Inside the storage tank 1, parallel to the heat-receiving panel 2, there is a dividing panel 4 adjacent to the side faces of the storage tank 1. On top of the heat-receiving panel 2, glass 6 is fixed using a special aluminum profile 5. On one of the faces of the storage tank is closed prison pipes 7 for supplying cold and draining hot water. On all surfaces of the storage tank 1, with the exception of the heat-receiving panel 2, thermal insulation 8 is installed.

An example of a specific implementation is shown in figure 1.

BSVN consists of a storage tank 1 in the form of a trihedral prism made of sheet metal, the large side face 2 of which is a heat-receiving surface coated with a matte black paint or having a selective coating. The required structural rigidity is provided by a power frame made of metal corners 3. Inside the storage tank 1, parallel to the heat-receiving panel 2, there is a dividing panel 4 adjacent to the side faces of the storage tank 1 and made of rigid heat-insulating material (for example, rigid foam). The presence of panel 4 provides thermosiphon circulation, as a result of which heated water from the gap between panels 2 and 4 enters the upper part of the storage tank 1, and cold water from the bottom of the tank 1 enters the gap between panels 2 and 4 and is heated. To reduce heat loss over the heat-receiving panel 2, a glass 6 is fixed using a special aluminum profile 5. On one of the faces of the storage tank, nozzles 7 are fixed for supplying cold and removing hot water. In this case, the pipe for draining hot water is located at the level of the upper edge of the separation panel 4.

All surfaces of the storage tank 1, with the exception of the heat-receiving panel 2, are thermally insulated, and the thermal insulation 8 can be located both on the external and internal sides of the structure. When the insulation is located on the inside, the external metal painted surfaces exclude the possibility of damage to the BSVN during transportation, installation and operation, thereby significantly improving its consumer and aesthetic properties. When the insulation is located on the outside, the metal consumption of the structure can be significantly reduced.

The only condition ensuring the preservation of hot water at night is to provide a level of analysis of hot water below the level of the "hot water" pipe in the BSVN. The supply of hot water to the consumer is ensured by the supply of tap water through the pipe "cold water".

The proposed design allows you to install BSVN on virtually any surface, fix it on the wall of the house, embed in the slope of the roof of the building.

Claims (1)

Domestic solar water heater, consisting of a water storage tank made in the form of a trihedral prism, in which one of the faces is a heat-receiving surface made of sheet metal coated with matt black paint and having a sheet of glass coating, in addition, inside the storage tank in parallel a heat-absorbing surface has a dividing panel adjacent to the side faces of the storage tank and made of rigid heat-insulating material, while in the storage tank there are patras bki for supplying cold and hot tap water, and all surfaces of the storage tank, besides heat-receiving, heat-insulated from the inside or from the outside, characterized in that the pipe for discharging the hot water is at the upper edge of the divider panel.