CZ20011199A3 - Heat accumulator containing heat-exchange apparatus - Google Patents

Abstract

The arrangement comprises a thermal store (1) containing a heat exchanger (2) which is characterised by the heat exchanger (2) being provided with at least one divider wall (3) inside the vessel of the thermal store (1) to form a discharge flow channel (5). This arrangement raises the coefficient of heat transfer of the immersed heat exchanger (2) by accelerating the gravity flow over the heat exchanger (2).

Description

Technical field

The invention relates to heat exchangers placed in containers, for example heat accumulators.

BACKGROUND OF THE INVENTION

The prior art solutions of exchangers housed in vessels, mostly heat accumulators, require considerable heat exchange surfaces and relatively bulky vessels. This is particularly pronounced in cases where there is a high consumption of heat energy by means of exchangers relative to the stored energy in the vessel. The size of the exchanger required to provide the required power is given both by the low coefficient of free, the exchanger on the side immersed in the undesired temperature drop, ie the natural heat transfer in the liquid in the vessel and the accumulated liquid caused by disturbed stratification. With a considerable consumption of thermal energy, convection currents are created which disrupt the stratification and cause thermal homogenization of the water content. The present solution, due to the homogenization of the temperature state of the accumulated liquid, has a limited possibility of pumping useful energy from the accumulator, defined by the temperature drop of the liquid flowing from the exchanger below the minimum required value. For example, this is an important factor in utilizing the thermal energy of low temperature sources. The prices of exchangers and accumulators designed this way are relatively high. In addition, bulky accumulators result in greater heat loss, enhanced by convective currents flowing on the inner surface of the accumulator and increasing heat transfer.

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SUMMARY OF THE INVENTION

These disadvantages are overcome by the arrangement of the exchanger and the vessel, for example a heat accumulator, according to the invention. Its essence is that it comprises at least one partition wall forming with the accumulator wall at least one discharging flow channel. The duct may be shaped, starting at the top and ending at the bottom of the vessel in which the exchanger is located. The exchanger is preferably located at the top of the channel and is arranged for smooth tube exchangers in at least two spirals so as to minimize the effect of the boundary layer formed on the surface of the exchanger, using a single row using shaped tubes.

In a preferred embodiment, the exchanger is designed so that the resistance of the individual coils of the exchanger is the same. Preferably, at least one internal heat source, for example an electric heating element or heat exchanger, is disposed in the lower part of the vessel.

The supply from an external heat energy source, such as a boiler, is preferably situated at the upper end of the discharge channel. It is also suitable that the return line of the charging and discharging circuit, for example a heating circuit, is located at the bottom of the vessel.

Preferably, on the pipeline through which the liquid enters the vessel is placed a device reducing the inlet flow rate to prevent disruption of stratification.

In a preferred embodiment, the volume of the vessel and heat transfer surface is divided into two or more portions or vessels so that they are connected in series, both exchangers and portions of the vessel or individual vessel.

The advantage of the solution is, in particular, that it increases the critical coefficient of the free, i.e. natural heat transfer, of the exchanger on the side immersed in the liquid in the vessel by disturbing its arrangement.

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The emerging boundary layer on the surface of the exchanger on the liquid-immersed side and also by accelerating the gravity flow of the liquid contained in the vessel through the exchanger by means of the discharge channel with the exchanger located in its upper part. When designing the exchanger arrangement, it is necessary to take into account the temperature of the accumulated liquid, the temperature of the liquid entering and leaving the exchanger, the flow rate and the geometric shape of the accumulator.

The exchanger in the flow channel cools the liquid and fills the flow channel with the cooled liquid which creates a column of cooled liquid and results in a driving force that accelerates the flow through the exchanger and thereby increases the heat transfer coefficient above those common for exchanger submerged in vessels.

The use of a flow channel results in a separation of the flow of the cooled liquid from the accumulated liquid, which allows vertical piston movement of the accumulated liquid upon the withdrawal of thermal energy and thereby maintaining stratification, i.e. thermal stratification, increasing the efficiency of the accumulator.

The exchangers and vessels designed in this way are smaller than hitherto used and thus cheaper.

The heat loss of the accumulators so designed is lower, on the one hand, and also because the circumference of the vessel formed by the discharge channel is at a temperature lower than the accumulated liquids.

A further improvement in the efficiency of the solution can be achieved by dividing the volume of the vessel and the heat exchange surface into two or more portions or separate vessels so that they are interconnected in series, both exchangers and portions of the vessel or individual vessel. This will increase the efficiency of storage and allow more useful energy to be drawn from a given volume, while allowing the use of different energy levels of heat sources and the supply of thermal energy

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Various temperature levels as needed while maintaining all the advantages of the invention.

Heat exchangers and accumulators designed in this way are capable of using up to 30% more useful energy (defined by decreasing the temperature of the liquid flowing from the exchanger below the minimum required value) when using low-temperature sources than conventional solutions while saving 20% of heat exchange surface. Higher energy efficiency, lower heat losses and the possibility to save on investment costs is a significant benefit for the use of environmentally friendly low-temperature alternative

sources of heat and can decide economically advantageous. BRIEF DESCRIPTION OF THE DRAWINGS whether it is their deployed Exemplary thermal design battery according to this The invention will be described in more detail p using the attached drawings.

Fig. 1 shows a schematic vertical section of an accumulator with a double-row heat exchanger and a flow discharge channel. FIG. 2 shows two connected accumulators in a schematic vertical section. Fig. 3 is a vertical schematic sectional view of a three-part accumulator with multiple thermal energy sources and power consumption at different heat levels.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an accumulator 8 formed by a cylindrical body. In the upper part of the accumulator 6 there is a two-row heat exchanger 2 consisting of two separate coils connected at the upper and lower ends of the exchanger 2. The spirals are spaced apart from each other and the partition 3 and the outer casing of the accumulator. φφφ φ φ · φφφ · Φ Φ · · · · · 9 * *

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-5the required heat transfer coefficient. The accumulator 1 is provided with either a circular shaped partition 3 or a straight circular partition 3, which forms a flow discharge channel 5 with the outer casing of the accumulator 1. The purpose of the shaped partition 3 is inside the battery compartment 1.

The heated liquid inlet 7 is located at the bottom of the exchanger 2 and the heated liquid outlet 8 is located at the top of the exchanger

2. The liquid supply from the external heat source 9 is located in the upper part of the accumulator 9. The deflector 10 prevents disturbance of the thermal stratification and directs the supplied liquid to the flow discharge channel 5, thereby further increasing the heat transfer coefficient. The charging circuit return line 11 is connected at the bottom of the accumulator 1. Alternatively or additionally, the accumulator 6 may be provided with an internal heat source 15, for example an electrical heating element located at the bottom of the battery body 1. If necessary, the discharge to the discharge circuit 12 is located in the upper part of the accumulator 6 and the return line 13 is located in the lower part of the accumulator 1 at the end of which the device 14 for reducing the input speed is located.

FIG. 2 schematically shows the connection of two accumulators 6 in series. The first accumulator 6 is connected to the second accumulator 6 by a connecting line 6. The accumulators 6 may be in close proximity or possibly form a single container and the connecting line 6 may be formed by an intermediate wall. The heated liquid is supplied to the lower part of the exchanger 2 of the lower accumulator 1. The heated liquid then flows through the connecting line 6 from the upper part of the exchanger 2 of the lower accumulator 1 to the lower part of the exchanger 2 of the upper accumulator 1. In the upper part of the accumulator 8 there is a liquid supply from an external heat source 9. The return line 13 of the charging circuit is connected in the lower part. φ φ · φ φ φ · ·

The lower battery 1 and the discharge circuit 12 are located in the upper part of the upper battery 6.

FIG. 3 shows a three-part accumulator according to the invention with a plurality of thermal energy sources and energy consumption at different thermal levels. The accumulator 1 is divided between the compartments 22 and 23 into three compartments 9, 20 and 21. The heated liquid supply is to the lower part of the exchanger 2 of the lower compartment 19 and the heated liquid then flows through the connecting auxiliary pipe 4 from the upper part of the exchanger 2 of the lower compartment 19 to the lower compartment. exchanger 8 of the central space 20, from whose upper part it further flows through another auxiliary line 8 to the lower part of the exchanger 9 of the upper space 21 of the accumulator 1 and the heated liquid then exits through the outlet.

In the lower part of the lower space 19 there is an internal heat source 15 with the lowest energy level. In the upper part of the central space 20 there is a liquid supply from the heat source 9 of a higher energy level and the return line 11 of this charging circuit is connected in the lower part of the central space 20. In the upper part of the upper space 21 and the return line 11 is at the bottom of the upper space 21.

Discharge circuits according to the desired temperature level are connected to the appropriate compartments of the accumulator 1. The outlet to the discharge circuit 12 requiring the highest temperature level is located at the top of the upper space 21 and the return line 13 is located at the bottom of the upper space 21. a lower heat level is located at the top of the central space 20 and a return line 13 at the bottom of the central space 20. If the temperature of the liquid returning from the discharge circuit 12 is lower than the energy level in the lower space? connect at the bottom of the bottom space 19.

Claims (8)

PATENTOVÉ N O R O KY A heat accumulator (1) comprising a heat exchanger (2), characterized in that the heat exchanger (2) is provided with at least one partition (3) inside the accumulator body (1) to form a discharge flow discharge channel (5), A heat exchanger (2) formed of at least two cascade-shaped spirals and / or one shaped pipe is arranged in the flow discharge channel (5). Thermal accumulator according to claim 1, characterized in that at least one internal heat source (15) is located in the lower part of the accumulator container (1). Heat accumulator according to claim 1, characterized in that at least one external heat source (9) is located in the upper part of the accumulator (1) above the exchanger (2) and in the lower part of the accumulator body (1) is a return pipe (11). ) of the charging circuit. Thermal accumulator according to claims 1 to 3, characterized in that it comprises at least one internal thermal energy source and at least one external thermal energy source. Thermal accumulator according to claims 1 to 4, characterized in that at least one discharge circuit (12) is connected to the upper part of the accumulator (1) and the discharge circuit return line (13) is connected to the lower part of the accumulator body (1). Heat accumulator according to claims 1 to 5, characterized in that it consists of at least two accumulator containers (1) arranged in series, their internal spaces being interconnected by a connecting line (6) and the actual exchangers (2 ', 2' ') are connected in series with an auxiliary pipe (4). Heat accumulator according to one of Claims 1 to 5, characterized in that the accumulator (1) and the exchanger (2) are divided into at least two compartments (19, 20, 21) of a separate partition (22, 23), , 20, 21) are connected in series. Heat accumulator according to claim 7, characterized in that the heat sources have different energy levels in the individual spaces (19, 20, 21), wherein in the lower space (19) there is a source with the lowest energy level and in the upper space (21). is the source with the highest energy level.