FR2461220A1 - THERMAL EXCHANGER COMBINED WITH A HEAT ACCUMULATOR - Google Patents

Abstract

THE INVENTION CONCERNS A HEAT EXCHANGER. IT IS COUPLED TO A THERMAL ACCUMULATOR DIVIDED INTO SEVERAL ZONES 11 TO 16 ISOLATED, CROSSED ONE AFTER THE OTHERS BY THE HEATED DUCT 9. THE HEATING DUCT 17 IS SEPARATED FROM THESE ZONES BY AN INSULATING BULKHEAD 18. A THERMAL TRANSFER LINK SINGLE IS PROVIDED FROM THE HEATING DUCT 17 TO EACH ACCUMULATION ZONE, THE ACCUMULATION ZONES BEING PLACED IN A DECREASING ORDER OF TEMPERATURE. WE CAN THUS WORK WITH HEAT SOURCES THAT DO NOT WORK WITH WELL DETERMINED TEMPERATURE DROPS.

Description

The invention relates to a heat exchanger

  than isolated against heat loss in the environ-

  combined with a heat accumulator, including

  both a heated duct and, separated from it, a heating duct, these two ducts being in heat exchange connection with a heat accumulating mass. Heat exchangers and accumulators of this category are practically used on all domestic water supply systems and in many other cases of use. A certain volume of drinking water stored in a tank is maintained at a storage temperature determined by reheat coils subjected to a source of

  heat, the focus of a heating system for example.

  When hot water is stored, the temperature of

  The temperature is lowered due to the addition of cold water in the storage tank, so that the heat source must again supply heat. As mentioned above, the heat source is normally a home for which a temperature drop can be assumed at all times.

  determined for heat transfer.

  However, when the heat source is a solar collector battery or, for example, the heat evacuated by any device (domestic wastewater for example), it is no longer possible to count, on the heat source side or the primary side, on a constant temperature level or a definite temperature drop in the direction of

  on the heat absorber or secondary side of the sample

  thermal gage. If, for such employment cases,

  exchangers and heat accumulators of conventional type

  that could be used, could

  a thermal reflux from the secondary side to the primary side. In case this reflux occurs

  in a period when available heat is particularly

  reduced, it could result in a cooling

consumption side.

  The object of the invention is to give a storage heat exchanger a structure such that in case of fluctuations in the temperature level on the heat supply side and / or on the heat consumption side, a heat reflux from the secondary to the primary

  can be avoided, even if the temperature drop is

  pour, structure through which also the heat available on the supply side of heat can

  be widely used on the consumer side.

  The provisions of the invention

  solve this problem by the fact that

  heat generator is divided into several areas of

  thermally insulated thermal cumulation of each other, to each of which is assigned a level

  of different temperatures, areas of thermal accumulation

  crossed one after the other, in a

  dre increasing corresponding to the following various temperature levels, by the heated conduit, by the fact that the heating conduit is separated from the thermal accumulation zones by a thermosolante partition, and by the fact that between the heating channel and each of the different areas of thermal accumulation, is

  provided a heat transfer link acting ex-

  in one direction, namely from the heating duct to the corresponding thermal accumulation zone of

  heat accumulator, heated parts, food

  heated ducts, different connections

  heat transfer sounds being achieved by the

  heated one after the other in the order

  corresponding increase in the sequence of the various

  temperatures of the corresponding heat accumulation zones. Thanks to the invention, are introduced

  in the heat accumulator and in the heat exchanger

  a forced temperature range and a thermal anti-reflux barrier. The one-way thermal transfer link can be provided by a cooling coil system with stop valves between the supply side

  heat and heat removal, valves will close

  automatically when there is a temperature drop. These valves do not react to the height of the temperature level but to the direction

  a temperature gradient between two different points

  ent. A simpler provision than this possibility

  solution consists in using ducts from each

  vertically arranged, their side of pre-

  heat removal being placed at the bottom and their heat supply side at the top, the return of the condensate taking place largely by gravity

  The heat pipes are well known.

  This expression must be understood to mean a hermetically sealed, watertight, tube-shaped or

  plate, made up at least in the sampling area

  heat and / or heat supply of a good heat conducting material, for example copper or aluminum, this chamber being filled

  a vaporizable heat transport medium and

  densable. The choice of medium is based on the temperature level at which the heat transport can be done. The heat pipe is normally provided with partly inside a capillary structure

  for the return of the condensed heat transport medium

  from the heat transfer side to the heat extraction side; this can for example be in the form of a striated texture of the tube or a

  groove structure of the inner surface of the tube.

  With this capillary structure, the condensate can be returned to the heat extraction side of the

  tube on a small level difference even at the

  - against the force of gravity.

  In the present use, this capillary structure must as far as possible, to prevent reflux of the condensate against gravity, be avoided, at least in the transition zone between the heated portion and the heating portion of the tubes. In this application, the condensate must only be transferred downwards, so that in case of reversal of the temperature drop, can not occur between the ends

  of the thermal tube a thermal transfer in the opposite direction

  se (assuming a high flow of condensate), that is,

  say on the secondary side to the primary side. Inside

  of the heated part of the thermal tube which

  tends to differ in level, the use of

  tion of an internal capillary structure is favorable;

  it makes it possible to moisten condensate the largest

  possible of the internal surface of the wall of the

  heated part, even when it is only

  filled with condensed liquid. This increases the heat transfer capacity. It is advantageous that between the heated portion and the heating portion of the tube is interposed a transition zone 25 cm long, vertical and free of any function. This sector of the tube must be well insulated thermally. he

  represents a safe distance between the two

  active transfer parts of the thermal tube, distance o can not be crossed in the direction of the top, according to

  the lessons learned so far, through the conden-

  sat. The filling of the heat pipes can be done

  by choice with ammonia, water or with a

  alcohol and water. At the hot point of the tube to which the thermal energy is brought, the fluid introduced

  vaporizes and relaxes quickly inside the

  be. At the points of the tube that yield heat, the vaporized fluid precipitates and condenses by yielding its heat to the wall of the tube. The condensate returns (here exclusively by gravity) to the points of the tube where the heat is brought. The amount of heat transferred by

  the fluid at the condensate-side tube partition is trans-

  placed on the outside, by thermal conductibility

  and convection, to the heat accumulating fluid.

  Given that at the heated or heated points of the

  tube, a change of state of the heat-exchange fluid takes place

  the transformation energy necessary for the change of state is transmitted for the most part under

  form of heat. The transformative energies

  brought to the mass of the coolant being significant-

  higher than the quantities of energy stored in

  by reheating a fluid, it is possible

  the transfer of quantity of coolant relative to

  small, to transmit a large amount of heat even at great distances and for relatively small temperature drops. By applying a determined pressure inside the thermal tube,

  it is also possible to ensure that the heat transfer

  that can take place for a temperature level

perfectly determined.

  The dam effect exerted by tubes of this conformation on a thermal reflux directed by

  secondary side to the primary side of the heat exchanger

  That accumulation is caused by preventing, as already said, the flow of condensate from heading in the direction of undesirable heat transfer. when

  there is a reversal of the temperature drop in the sample.

  For the thermal transfer inside the tube, the condensate should move, against gravity, from the primary side at the bottom to the secondary side at the top.

  can do without a capillary structure, we can not succeed

  only a negligible proportion. It is advan-

  tageux that the inner face of the tube is coated, in the transition zone, a hydrophobic lining; the

  thus minimally dampens the face

  and, therefore, does not tend to

  sector, to move upwards on the inter-

  do not against gravity. A slight tendency to moisten

  The transition between the condensate and the inner wall in the transition zone also leads, moreover, to a particularly rapid passage of the condensate in the primary part in the desired direction, with gravity.

  on the inner wall of the tubes. This promotes a trans-

  significant thermal fertility in the direction of transmission

  desired despite a neutral-function tube sector possibly

  interposed.

  condensate damping can be carried out

  chromium plating of the inner face or application thereon of a layer of polytetrafluoroethylene (ITFE). In the heating part of the tube however,

  the surface condition must favor pelvic condensation

  licular, as opposed to condensation in

  your. According to the lessons learned, a conden-

  pellicle allows, for small temperature differences between the inner atmosphere of the tube

  and its outer face, better heat transfer.

  As accumulating fluid, the water of consumption

  mation or industrial to heat secondary side can be used, the different accumulator zones

  of heat forming at the same time the heating duct

  of the storage heat exchanger. As flui-

  accumulation, one can however also use a

  material permanently enclosed in the accumulation zones

  lation, in particular a latent heat storage material. With such a configuration, a

  heat exchange between the heated duct and the material

  areas of thermal accumulation is to be expected

  through the duct partition. With the material

  latent heat exchanger also, phase transformation energy between liquid phase and phase

  solid or, on cold latent heat accumulators

  the enthalpy of reaction is practically

  waste gas and, to a lesser degree, thermal energy

  - corresponding to the warming. We obtain

  significantly higher accumulation densities

  high or, for a predefined volume of construction,

  higher accumulation capacities than

  during storage depending purely on the temperature.

  As a latent heat storage material, it is possible to

  use different substances or combinations of

  such as categories of temperature waxes,

  different forms of employment, in particular for

  melting points, depending on the differences

  temperature levels of accumulation zones

heat.

  Another advantage of battery accumulators

  their latent is that the heat exchange is always effected

  days at a certain temperature regardless of the capacity of accumulation, especially at the temperature of use and melting of the stored material. Thus, even when the storage capacity is partially discharged, relatively high temperature drops and therefore large thermal flows. This also contributes in a known way to a reduction of the built volume and

expenses.

  In what follows, the invention is still

  briefly explained with the help of three examples of

  illustrated by figures. These represent: - Figure 1, in longitudinal section, a first example of execution of a heat exchanger to

  accumulator according to the invention, with water

  as an accumulating agent.

  - Figure 2, in section, another embodiment of an accumulator heat exchanger, with as storage agent a storage material

latent heat.

  - Figure 3, in longitudinal section, a fragment of a thermal tube of the transition zone, as used in heat exchangers to

  accumulation shown in Figures 1 or 2.

  - Figure 4, in section, another example of

  the production of a heat exchanger with accumula-

  me to the invention, with the resistant thermal zones

with pressure.

  The heat exchangers with accumulators in accordance with the invention and represented in FIGS. 1 and 2 have an accumulation tank 2 subdivided by thermo-insulating intermediate partitions 7 and

  7 ', in several zones of heat accumulation repre-

  from 11 to 16 and from 11 'to 16'. The storage tank

  mulation 2 is also provided, in order to avoid

  from the heat to the external environment, equipped with thermal insulation 1. Below the storage tank 2, is disposed a conduit 17 inserted in

  thermal insulation 1 and separated from the storage tank

  The purpose of this thermosolant device is to prevent thermal reflux from gaining, in the event of reversal of the temperature drop, and from the secondary side of the heat exchanger with accumulation, the primary side

  (17). The heat supply duct located next to the

  It is expanded into a room and is equipped, with its two ex-

  tremities, connectors 5 and 6 serving respectively for feeding and return. It will be discussed further from the internal parts of the duct bearing pins 21, 23 and 24. The accumulation tank 2 is crossed

  by the heat-absorbing duct 9 (on the secondary side

  dary) or 10 (Figure 1 or 2). In the exemplary embodiment of FIG. 1, the intermediate partitions 7 are provided, between the different heat zones, with a passage opening 8 reserved for industrial water stored as accumulation mass. The passage openings of two adjacent intermediate partitions are arranged with a certain offset with respect to each other; it results in the constitution of a conduit

  a heat absorber whose meanders pass through

  areas of thermal accumulation from 11 to 16,

  equipped at its ends, at the level of the areas of

  thermal cumulation 11 and 16 occupying the extreme positions, an inlet connection (3) and a return connection (4). In the embodiment of FIG. 2, the two intermediate partitions 7 'are closed; the 11 'to 16' thermal accumulation zones thus totally compartmentalized with respect to each other contain as latent heat mass at different temperature levels. The heat-absorbing duct 10, equipped with the inlet connection (3) and the return connection (4), is traversed, as a particular channel, by all the thermal accumulation zones from 11 'to 16' and is in communication with each of them by heat-exchanging ribs 19. At the different heat accumulation zones of 11 to 16 and 11 'to 16', different temperature levels (from T1 to T6) are affected. as shown in Figure 1 the dashed lines to

  diagram form. The different accumulation zones

  heat are reached by the absorber duct

  of heat 9 or 10 one after the other in the

  increasing temperature levels, that is to say

  that the heat accumulation zone 16 or 16 'associates

  at the lowest temperature level T6 is reached

  the first by the heat-absorbing channel 9 or and the heat accumulation zone II or 11 'associated with the highest temperature level T1 the last. On the accumulation heat exchanger

  according to Figure 1, which uses industrial water

  the like accumulating mass of heat, staging

  temperatures occur on its own during the operation of

  this heat exchanger. On the example of execu-

  of Figure 2, which includes accumulated material

  latent heat in the different zones

  cumulative heat, the melting point of the

  materials intended for the accumulator zones of

  heat is to be chosen according to the temperature levels

  erations sought, the temperature

  so here predetermined by the choice of materials of ac-

cumulation.

  To be able to transmit the heat of the con-

  duit 17 heat absorber to different areas

  accumulators of heat on the secondary side of the sample

  thermal storage unit, taking into account the

  temperature, it is provided for each heat accumulator zone at least one heat pipe (from

  a to 20b) each corresponding to a temperature level

  erase (from T% to T6). Each of the different heat pipes

  there is a heat-absorbing portion 21 extending into the heat-conducting conduit 17,

  another part 22 of the thermal tube, also

  heat sink, plunging deep into the corresponding heat storage area. To make the transmission of heat more favorable, inside the primary duct 17, to the heat-absorbing part there is

  21 of the thermal tube, a relatively short part, that

  the latter is equipped with several heat exchange ribs 23. Moreover, in the primary channel are provided, to avoid flow turbulence, in relation to the position of the intermediate partitions

  7 or 7 'of the secondary part of the heat exchanger

  than flow accumulation, flow deflecting plates ensuring a flow through the primary channel

  meanders of the heat-generating fluid. Thus, the

  duit 17 heat debtor is in communication, by

  a heat transfer chain acting unilaterally

  towards the secondary side of the storage heat exchanger, with the different zones

  of heat accumulation at various temperature levels

  these different zones being reached by the heat-inducing duct (indirectly) in a

  descending order corresponding to the temperature level

  tures. The coolant yielding the heat therefore reaches

  the thermal tube 20a belonging to the accumulation zone

  heat 11 or 11 'having the temperature level

  highest T1 level first, and lastly the highest

  20f of the heat storage zone 16 or 16 'having the lowest temperature level T6.

  The operation of the heat accumulator

  Figure 1 is as follows: Heat transfer fluid

  yielding the heat and coolant absorbing the heat

  they come into contact with heat exchange according to the principle of the countercurrent, the heat pipes and the heat-insulating partition 18 making sure, however, that the heat transfer takes place only in one direction, namely on the primary side on the secondary side. The

  storage tank being divided into several

  of thermal accumulation, isolated from each other

  thermally, it occurs in the heat

  on the secondary side, provided that the

  poured from the storage tank takes place in

  stagnation, a temperature rise in the tank

  see accumulation, so that at each accumulated zone

  latrice of heat, is assigned a level of

  different temperature. The higher temperature level

  T1 is very slightly below the

  coolant temperature giving up heat during the time when the higher temperature level could

  form. If, for any reason, the temperature

  inlet of the heat-carrying coolant of

  reaches below the temperature level T1 in the heat accumulating zone 11 and stabilizes, for example, at a level slightly above the temperature level T3 of the heat accumulating zone 13, then the temperature drop compared to the first two heat accumulator zones 11 and 12, it is reversed from the secondary side to the primary side of the storage heat exchanger. The

  heat pipes 20a and 20b are more strongly heated up

  in their upper part than in their lower part. Moreover, the partition of the storage tank 2 is hotter in the sector of the first two accumulator zones than the coolant

  heat sink in duct 17. Isolation wall

  Lante 18 prevents heat flow from the secondary side to the primary side through the tank wall. As the heat pipes are coated, on their smooth inner face in the transition zone, with a chromium lining 26 or hydrophobic PT E 27, any condensate could only flow downwards by gravity. A rise of the condensate in the upper parts 22 of the heat pipes is prevented by the absence of a structure

  capillary. In reversed temperature fall, the condensa-

  sat is therefore concentrated entirely in the lower part of

  absorbing the heat of the capillary tube and

  remains; the coolant circuit allowing a trans-

* Thermal fertility inside the thermal tube is then interrupted. A thermal reflux from the first two thermal accumulation zones II and 12

  on the primary side of the exchanger is therefore ex-

  clu. Only when there is consumption of water stored in thermal accumulation zones

  their temperature gradually decreases until

  Calf of highest temperature finally fed

  primary school (in the example chosen, the tempera-

  T ^). It is also only when, in zones 11 and 12, there is a lower temperature than at the entrance to the heating duct 17, that can again occur in the sector of the heating parts of the

  20a and 20b, a condensation of the transmission fluid

  thermal vapor phase inside the tubes,

  and therefore a heat transfer on the primary side

  to the secondary side of the exchanger. Temperature

  of entry continuing to fall in the fluid calopor

  heater on the primary side of the heat exchanger, this

  process is renewed accordingly; areas of

  thermal cumulation whose temperature is

  above the inlet temperature on the primary side can still be "used empty" without intervening from the secondary side, a thermal reflux towards the

  primary side. Only when the areas of

  the temperature of service above the inlet temperature are reduced,

  by appropriate consumption, at the temperature of

  a new thermal transfer of the

  primary tee at the secondary side. The accumulation zones

  temperature are thus stabilized on the temperature

  the highest corresponding primary side input.

  When there is a lowering of the temperature on the

  mayor, there is still some

  lume stored, volume at the highest ni-

  temperature calf finally obtained.

  The operation of the storage heat exchanger of Figure 2, which uses a material

  latent heat accumulator, is quite ana-

  logue. The different temperature layers and thermal accumulation zones are also here, if one

  exception of some unavoidable thermal bridges

  isolated between them in the heat exchange plan.

  - The different areas of the secondary side may, from

  water consumption and when the temperature is

  Primary re-decline, one after the other, starting with the accumulator having the highest service temperature, being "used idle", the temperature level, however, staying at the phase transformation point as long than

  liquid material still remains, when cooling

  in the thermal accumulation zone. It's not

  when the heat accumulating material laten-

  has passed entirely into the solid phase

  erature begins to fall within a thermal accumulation zone. The temperature range predetermined by the selection of the material is thus maintained longer than with the example of execution of the

  figure 1; Moreover, with equal

  truction, the accumulation capacity is greater inside a thermal accumulation zone, since the phase transformation energy is stored

as an important contribution.

  The storage heat exchanger in the pressure-resistant embodiment shown in FIG. 4 is constituted on the model of the exchanger of FIG. 1; the accumulating mass of heat is here a liquid of common use, water for example. The

  different heat accumulation zones (only two

  are shown in Figure 4) are

  killed, in the secondary part of the exchanger, in a pressure tank 30 in the form of a bottle which can withstand the pressure of

  industrial water. On the representative execution example

  The single-way heat exchange link between the primary side and the secondary side of the storage heat exchanger is constituted by a bundle of tubes 31 which can be introduced into the pressure tank via an opening 32 relatively widely. sized. The different pressure tanks are connected to each other by a pipe 34 which can be connected to the upper part of a pressure tank and opening to

  the lower part of the neighboring pressure tank.

  Below the insertion opening 32 is provided

  as the primary part of the heat exchanger

  mulation a box-shaped heat exchanger in which absorbs heat-absorbing side, the tubular bundle. The various heat exchangers 35 of the

  primary side associated with thermal accumulation zones

  or pressure vessels are connected to each other by short pipes 36. To prevent heat loss to the outside and a fortuitous heat exchange between secondary side and primary side, the pressure tanks 30 and the

  box-shaped heat exchangers 35 are

  with thermal insulation 37 or 38; the coins

  may be insulated with foam in the

  for example, appropriate formwork. Each meeting

  pressure vessel-may be installed vertically on supports 39, which, however, must as far as possible be mechanically connected

  pressure tank without forming thermal bridges

  nomic. The tubular bundle distribution of the heat pipes (third example of execution) was

  intended to increase the thermal transmitting

  of the heat accumulating mass and the heating sector of the tubes in the secondary part of the storage heat exchanger. In the

  secondary part, one can not count on the ex-

  tubes, only on a weak convection, so on a weak heat transfer. On latent heat accumulators, in particular, which comply

  model in Figure 2, a large area of trans-

  Heat mission in the heating part of the tubes is important because in these use cases, the latent heat accumulator materials are temporarily or partially solid, or at least of a very viscous consistency, so that a free convection can not take place; heat transfer takes place

  here almost exclusively by conductivity. To increase

  the heat exchange, it is therefore useful that the tubes describing meanders and / or be divided into

  beam, and / or be equipped with ribs or protectors

  beries facilitating the thermal exchange. -

Claims (7)

  1) Heat exchanger insulated against heat poets in the environment and combined with   a heat accumulator, including a heating duct   and separated therefrom, a heating duct, these two ducts being in heat exchange connection with a heat accumulating mass, characterized in that the heat accumulating mass is divided into several zones of thermal accumulation ( 11 to 16, 11 'to 16') thermally insulated from one another,   each of which is assigned a temperature level   different (from T1 to T6), thermal accumulation zones crossed one after the other, in   an increasing order corresponding to the sequence of   temperature levels (from T1 to T6), by   heated (9, 10) by the fact that the heating duct   phantom (17) is separated from the thermal storage zones (11 to 16, 11 'to 16') by a thermally insulating partition (18), and by the fact that between the heating channel (17)   and each of the different thermal accumulation zones   that (11 to 16, 11 'to 16') is provided a heat transfer link acting exclusively in one direction,   i.e. heating conduit (17) to the charging zone   corresponding thermal melt (11 to 16, 11 'to 16') of the heat accumulator, the heated portions (21), fed by the heating duct (17), of the various heat transfer bonds (20a to 20f) being reached by the heated duct one after the other in descending order corresponding to the following of the different temperature levels (of T1   at T6) corresponding heat accumulation zones (11 to 16, 11 'to 16').   2) Heat exchanger according to the claim   1, characterized in that the connection of   thermal transfer is carried out each time by a   be thermal (from 20a to 20f) designed according to the temperature level (T1 to T6) of the corresponding thermal accumulation zone (from 11 to 16, from 11 'to 16'), thermal tube oriented at least approximately vertically close, the heating duct (17) being arranged lower than the zones of heat accumulation in the exchanger   thermal and thermal tubes (from 20a to 20f) penetrate   in heating tubes (22) in the storage areas   thermal insulation (11 to 16, 11 'to 16') and heat pipes.   (21) in the heating duct (17).   3) Heat exchanger according to one of the   I or 2, characterized in that each zone of thermal accumulation (from 11 to 16) is filled with a liquid of common use, in particular water, playing the role of mass accumulating heat, by the neighboring accumulation zones (11 and   12, 12 and 13, etc.) are in communication with one   verture (8) allowing the passage of the flow and that the succession of zones of thermal accumulation (from 11 to 16) is thus itself, at the same time, led me heated (9) (Figure 1).   4) Heat exchanger according to one of the   I or 2, characterized by the fact that   The heat exchanger (10) is, in the flow plane, distinct from the different zones of heat accumulation (from 1 to 16 ') and, by its good heat-conducting partition (19), is in exchange connection. with the heat accumulating mass of each of the thermal accumulator zones (from 11 'to 16') taken on one after the other.   ) Heat exchanger according to the claim   4, characterized by the fact that each accumulated zone   thermal latrice (from 11 to 16) is filled with a   latent heat accumulator of a different temperature level (from T1 to T6), material playing the   heat accumulating mass rale.   6) Heat exchanger according to one of   claims I to 5, characterized in that   the heat pipes (from 20a to 20f) have, at least in the transition zone between the heated portion (21) and the heating portion (22), a face   smooth interior (25) and without mounting element.   7) Heat exchanger according to the claim   6, characterized in that the heat pipes   are, in the transition zone, equipped with a gasket (26, 27), preferably made of chromium (26) or PTFE (27), which repels the condensation liquid (28). stored heat transfer fluid.   8) Heat exchanger according to one of   claims I to 7v characterized by the fact that   the different areas of heat accumulation are   shaped into different reservoirs, shaped like   dies or other form, resistant to pressure (Figure 4).