Field of technology

The invention concerns a construction solution of compact evaporator with closed loop to receive heat from the heat source which is in close contact with the evaporator by means of the heat pipes and heat exchanger, through which the heat flows to delivery point. The invention belongs to the field of heat technology and heating systems.

Prior state of the art

In the prior state of art, the commonly produced heat pipes with back loop are constructed by welding of the steel pipes into a single functional whole. Such construction solution requires high precision of the individual components, a lot of preparations with ability to highly precisely position a set of pipes, the wielding aggregates, etc. With each increasing number of the joints the risk of leakage increases; such risk is a limiting factor in the case of pressure equipments, which affects the functionality and lifetime of the equipment. Large amount of joints and switches diminishes the lifetime of the equipment, especially when the temperature gradient increases and when deformations and uneven tensions result from uneven horizontal distribution of a permeating heat.

In the field of computer technology such cooling systems intended for cooling the power sections of the computers also use the specially constructed heat pipes, such as the ones disclosed in European patent application EP 2 157 391 Al, where the heat pipe contains a semipermeable material membrane separating the liquid component of the working medium from its gas component.

Next, a cooling system working on the principle of a heat pipe working with high temperatures and high pressures from the working medium is known, as disclosed in published international application WO 2011/121819. It is a dual-chamber heat pipe with relatively complicated construction. The deficiencies of the abovementioned constructions of the cooling systems with heat pipes and difficult production of evaporators suggested creation of such evaporator which works on the principle of heat pipe which production will be easy. This resulted in the further disclosed construction solution of a compact evaporator with closed looped to receive heat from the source which is in close contact with the evaporator by means of heat pipes and heat exchanger, through which the heat flows to delivery point, which is the subject matter of this invention.

Subject matter of the invention

Abovementioned deficiencies are remedied by the construction solution of a compact evaporator with closed looped to receive heat from the source which is in close contact with the evaporator by means of heat pipes and heat exchanger, through which the heat flows to delivery point. The essence of the invention lies in the fact the technical solution describes a device which can be used, for example, for heat recovery in various systems and devices. The main member of the device is a metal panel which in its internal arrangement contains a set of vertically oriented openings alongside the upper and lower horizontal opening. The metal panel can be advantageously made of steel or cast iron or aluminum alloy. Other suitable materials are not excluded. The metal panel can be equipped by anchor element, too. The holes can be created, for example, by drilling through the openings, or the channels. In another approach, the inner channels can be created during casting of the panel. In a preferable arrangement the cross-section of the openings or channels will be circular or elliptical, which creates conditions for coping with high pressure inside the panel. By this the invention differs significantly from the extruded panels where the channels with angular cross-section are used for carrying the heat carrying medium. In case of high pressure the angular cross-sections cause uneven deformations, which leads to leakage and even to system failure. The lower horizontal opening, which functions as a distributor of the liquid medium, and/or the upper horizontal opening, which functions as an accumulator of the evaporated medium, can be construed as blind. If the lower horizontal opening and/or the upper horizontal opening is through, then one entry to the opening is produced as nonfunctional - it can be, for example, permanently blinded, equipped by seal, and so on.

If both horizontal openings are produced as through, which can be a result of technological reasons during drilling (more efficient machining) or during casting (holding the core in the template), the opposite sides of the openings will be blinded. The connection of distributor and accumulator from the metal panel to the heat exchanger will be usually led on the opposite sides in order to achieve a uniform flow in the vertical channels, but for specific applications a different connection can be used as well.

The crucial advantage of the solution according to this invention is a usage of a monoblock construction of the metal panel of the evaporator, especially the one with the flat contact surface. The metal panel is produced in one piece as a single compact component. The contact surface will be usually flat; when needed, the panel can have different contact surface, for example with round or crooked shape, which will better correspond to the outer shape of the heat source. With this arrangement we achieve excellent heat transfer from the cooled surface to the surface of the panel and subsequently an optimal heat transfer to the liquid medium in the heat pipes without the resistance of unnecessary boundary layers, which would be required if multilayer or multipart construction is used.

The heat carrying medium in contact with inner circuit of the vertical circular channel has, according to respective position, various lengths of paths of transfer of the heat from the contact surface; however, such path is always created by a compact block from a metal material, that is, a material with good thermal conductivity. The channel with circular cross-section is resistant to high pressure and the integrity of the monoblock of the panel diminishes possible uneven temperature distribution, too. This all is achieved synergistically by a simple construction of the evaporator with only two outer joints, which is essentially a physical minimum necessary for connection with the loop and the capacitor.

Both sides, that is, both surface of the metal panel can be used for contact with the source of heat; however, preferable arrangement is possible, where one surface is intended for the contact with the heat source and the second surface is equipped by heat isolation in order to prevent heat loss. First surface can be machined for achieving high flatness, which results in good adhesion to the heat source; alternatively, this surface can be equipped by heat transfer sealant. The opposite side can be untreated (e.g. in the state after casting), or it can be equipped by heat isolation suitable for particular temperature conditions.

Vertically arranged openings are filled by the strictly defined amount of the filling, which is liquid working medium. This working medium is contained in the lower horizontal opening. Liquid working medium can be water, water- based liquids, liquid hydrocarbons such as ethanol, and so on. The set of vertically arranged openings alongside the upper horizontal opening form evaporating part of the heat pipes. The device works with the heat transfer by changing the phase of the substance from liquid to gaseous in the hermetically closed tubes - in this case openings - of the heat pipes on the principle of heating of the working medium by the thermosiphon effect. During the operation of this device there is the retrieval of the heat from the heat source; the heat is subsequently transferred by heat pipes and by doing so the energy is transferred through heat exchanger to the delivery point. The working medium is subsequently cooled and the condensate runs through the return pipe back to the heat pipes.

The heat exchanger is located on the same level or above the level of the upper horizontal opening. By doing so the circulation of the liquid working medium by means of thermosiphon effect is achieved. Within this arrangement the liquid working medium evaporates in vertical openings and ascends to the heat exchanger. There it condensates and descends through return pipe back to the metal panel.

The heat exchanger will usually be of the liquid/liquid type. Secondary circuit with the liquid will lead the heat out of the heat exchanger. The heat exchanger can have tubes with the oppositely oriented secondary circulation or it can have plate heat exchange surfaces.

The benefits of such device are clear from its outward effects. These effects lie mainly in the fact that the circulation of the working medium is ensured without the circulation pump, that is, by means of thermosiphon effect. Usage of the heat pipes in the device ensures that the device as such is of low weight; the device has quick thermal effect and the costs for production and maintenance of the heat pipe are low. The device has long lifetime and it is environmentally friendly.

The solution according to our invention replaces the set of heat pipes, which would have otherwise been needed to be connected by welding of the steel pipes into one functional whole. The invention significantly simplifies the production technology of the heat pipes (a lot of preparations with high precision of positioning of the set of pipes is no longer necessary, as is the realization of welds, or necessity to use the welding aggregates, etc.). Moreover, with regard to the fact that there is a monoblock, the risk of leakage - a limiting factor affecting the functionality and lifetime of the device - is eliminated. From the point of view of operating parameters, such produced device is mechanically more resistant to the internal pressure and to the high temperatures from the heat source. It can work in high temperatures, too (e.g. above 400°C). The steel plate from the monoblock can be directly attached to the heat source without the necessity to use another panel, which would otherwise have to encircle the weldment comprising of set of heat pipes from the steel tubes. The device itself has low weight, fast thermal effect, and low production and maintenance costs of the heat pipe. Brief description of drawings

Construction solution of the compact evaporator with the closed loop to retrieve heat from the source, whereby the evaporator is in close contact with the source by the means of heat pipes, is present on the attached drawings. Fig. 1 depicts the evaporator with closed loop in three views. Fig. 2 depicts axonometric view on the whole arrangement of the evaporator with the closed loop.

Examples of realization

It is obvious that individual realizations of the invention are presented for the illustration purposes only, and cannot be interpreted as limiting the scope of technical solutions. A person skilled in art can find many equivalents to the specific realizations hereby described by routine experimentation only. Such equivalents fall within the scope of protection of subsequent patent claims. The dimensioning of the device, as well as the choice of suitable materials and construction arrangements, present no challenges to a person skilled in art, and therefore they are not analyzed in detail.

It is also obvious that modifications stemming from the essence of the invention can be many.

Example 1

This solution of compact evaporator with closed loop to receive the heat from the surfaces of the heat source with high temperature potential, which is in close contact with the heat source by means of the heat pipes according to this invention, is in this example introduced by following description and it is depicted on fig. 1 and 2. The main member of the compact evaporator is a metal panel 1_, which in its internal arrangement contains a set of vertically oriented openings 2 alongside the upper and lower horizontal opening 4, 3. The metal panel \ is made of steel. The metal panel 1 is equipped by anchoring elements which are not depicted. The vertical openings 2 and upper and lower horizontal openings 4, 3 are in the form of blind drilled holes. Vertically arranged openings 2 are filled with precisely set amount of filler, which is a liquid medium - water in this case. This liquid medium is contained in lower horizontal opening 3, too. The set of vertically arranged openings 2 alongside the upper horizontally oriented opening 4 are the evaporating part of the heat pipes. The working medium is subsequently cooled in the heat exchanger 5 and the condensate flows through return pipe 6 back to the heat pipes in the metal panel L

For the purposes of clarity, the inner construction of heat exchanger 5 is not depicted on figures 1 and 2. The heat exchanger 5 can have different arrangement; it can include plate exchanger, oppositely running pipes and so on.

In alternative realization, if the lower horizontal opening 3 and upper horizontal opening 4 are through, then its nonfunctional outlets are equipped by a seal, which is not depicted.

Example 2

This solution of compact evaporator with closed loop to receive the heat from the surfaces of the heat source with moderately high temperature potential, which is in close contact with the heat source by means of the heat pipes according to this invention, is in the alternative arrangement introduced by following description and it is depicted on fig. 1. The main member of the compact evaporator is a metal panel J_, which in its internal arrangement contains a set of vertically oriented openings 2 alongside the upper and lower horizontal opening 4, 3. The metal panel 1 is made of cast iron. The metal panel

1 is equipped by anchoring elements which are not depicted. The vertical openings 2 and upper and lower horizontal openings 4, 3 are here in the form of inner channels produced while casting of panel L Vertically arranged openings

2 are filled with precisely set amount of filler, which is a liquid medium - liquid hydrocarbon, ethanol, in this case. This liquid medium is contained in lower horizontal opening 3, too. The set of vertically arrange openings 2 alongside the upper horizontally oriented opening 4 are the evaporating part of the heat pipes. The working medium is subsequently cooled in the heat exchanger 5 and the condensate flows through return pipe 6 back to the heat pipes in the metal panel 1.

Industrial applicability

Compact evaporator with closed loop to receive the heat from the surfaces of the heat source, whereby the evaporator is in close contact with the heat source according to this invention, can be used for all devices that produce moderately and highly potential waste heat and it can operate without a circulation pump.

List of related symbols

1 - metal panel

2 - vertical opening

3 - lower horizontal opening

4 - upper horizontal opening

5 - heat exchanger

6 - return pipe

I - primary circuit (with evaporation of the heat carrying medium)

II - secondary circuit (which leads the heat from the heat exchanger)