Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
COMPACT HEAT EXCHANGER UNIT WITH MULTIPLE CIRCUITS
Document Type and Number:
WIPO Patent Application WO/2019/073322
Kind Code:
A1
Abstract:
The invention is an exchanger unit (1) with plates (10, 10'), comprising a single pack of plates (10, 10') facing and welded to one another, provided with ridges and depressions and passage holes so as to define a first circuit (11) for a primary fluid (C) suited to transfer heat, a second circuit (12) for a first secondary fluid (W) and at least one third circuit (139) for a second secondary fluid (H), said first secondary fluid (W) and said second secondary fluid (H) both being suited to receive heat from said primary fluid (C), wherein each one of said second circuit and third circuit (12, 13) is limited to a corresponding area (A, B) of said pack of plates (10), said first, second and third circuit (11, 12, 13) being hydraulically isolated from one another.

Inventors:
BENETTOLO, Ugo (C/O ZILMET SPA, Via del Santo 242, LIMENA, 35010, IT)
PIROVANO, Michele (C/O ZILMET SPA, Via del Santo 242, LIMENA, 35010, IT)
Application Number:
IB2018/057101
Publication Date:
April 18, 2019
Filing Date:
September 17, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ZILMET SPA (Via del Santo, 242, LIMENA, 35010, IT)
International Classes:
F28D9/00
Domestic Patent References:
WO2004113815A12004-12-29
WO2009151399A12009-12-17
Foreign References:
DE102016101677A12017-08-03
FR3000187A12014-06-27
DE102012105115A12013-05-29
Attorney, Agent or Firm:
ROCCHETTO, Elena (UFFICIO VENETO BREVETTI SRL, Via Sorio 116, PADOVA, 35141, IT)
Download PDF:
Claims:
CLAIMS

1. Exchanger unit (1) with plates (10, 10'), comprising a single pack of plates (10, 10') facing and welded to one another, provided with ridges and depressions and passage holes so as to define a first circuit (11) for a primary fluid (C) suited to transfer heat and circulating between alternating pairs of said plates (10, 10') facing each other of the entire pack of plates (10, 10'),

characterized in that in said pack of plates (10, 10') also the following are defined:

• a second circuit (12) for a first secondary fluid (W) suited to receive heat from said primary fluid (C), wherein said second circuit (12) is limited to a first area (A) of said pack of plates (10), in which the exchange between said primary fluid

(C) and said first secondary fluid (W) takes place;

• at least one third circuit (13) for a second secondary fluid (H) suited to receive heat from said primary fluid (C), wherein said third circuit (13) is limited to a second area (B) of said pack of plates (10) different from said first area (A), in which the exchange between said primary fluid (C) and said second secondary fluid (H) takes place,

said first, second and third circuit (11, 12, 13) being hydraulically isolated from one another.

2. Exchanger unit (1) with plates (10, 10') according to claim 1, characterized in that said two areas (A, B) are adjacent to each other, wherein said circuits (11, 12, 13) are defined between different pairs of plates (10, 10'), and wherein each plate (10, 10') has one side intended to be placed in contact with said primary fluid (C) and an opposite side in turn divided into two adjacent areas (10a, 10b), a first area (10a) intended for the circulation of said first secondary fluid (W) and a second area (10b) intended for the circulation of said second secondary fluid (H), wherein said areas in any case are hydraulically isolated from each other.

3. Exchanger unit (1) with plates (10, 10') according to claim 2, characterized in that said first area (10a) and said second area (10b) of each plate (10') are separated from each other by an axis (X) which lies crosswise with respect to the longitudinal development of the plate (10'), and wherein said plate (10') is provided with passage holes (111, 112) for said primary fluid (C), further passage holes (121, 122) for said first secondary fluid (W) created in said first area (10a), and further passage holes (131, 132) for said second secondary fluid (H) created in said second area (10b).

4. Exchanger unit ( ) with plates (10, 10') according to claim 1, characterized in that said two areas (Α', Β') are superimposed over each other, and wherein said two areas (Α', Β'), each constituted by a pack of plates (10) facing each other, are separated by a partition plate (20) provided with passage holes (21) for the passage only of the primary fluid (C) from the first area (Α') to the second area (Β').

5, Exchanger unit (1) with plates (10, 10') according to claim 4, characterized in that said plates (10) are of the known type, provided with holes arranged in such a way as to create said three hydraulically isolated circuits (1 Γ, 12', 13').

6. Exchanger unit (1) with plates (10, 10') according to any of the preceding claims, characterized in that said circuits (11, 12, 13) are arranged in such a way that the heat exchange between said primary fluid (C) and said first secondary fluid (W) takes place first and the heat exchange between said primary fluid (C) and said second secondary fluid (H) takes place thereafter.

7. Exchanger unit (1) with plates (10, 10') according to any of the preceding claims, characterized in that it comprises opening/closing means suited to open/close at least one of said circuits (12, 13), in such a way that the heat exchange between said primary fluid

(C) and said first secondary fluid (W) takes place at the same time as or alternatively to the heat exchange between said primary fluid (C) and said second secondary fluid (H).

8. Exchanger unit (1) with plates (10, 10') according to any of the preceding claims, characterized in that it comprises, for each one of said circuits (11, 12, 13), at least one inlet area (Hi, 12i, 13i) for the introduction of the fluid (C, W, H) coming from a hydraulic system and at least one outlet area (l lu, 12u, 13u) for the return of said fluid (C, W, H) into said hydraulic system.

9. Exchanger unit (1) with plates (10, 10') according to any of the preceding claims, characterized in that the circulation of said primary fluid (C) takes place in the same direction with respect to said first secondary fluid (W) in said first area (A) and in the opposite direction with respect to said second secondary fluid (H), or vice versa.

10. Exchanger unit (1) with plates (10, 10') according to any of the preceding claims, characterized in that said plates (10, 10') are designed in such a way that the exchange surface between said primary fluid (C) and said first secondary fluid (W) is equal to or different from the exchange surface between said primary fluid (C) and said second secondary fluid (H), and wherein each one of said areas (A, B) intended for the heat exchange between said primary fluid (C) and each one of said secondary fluids (W, H) has such specific and predetermined performance characteristics as to optimize the performance of said circuits (11, 12, 13).

Description:
COMPACT HEAT EXCHANGER UNIT WITH MULTIPLE CIRCUITS

DESCRIPTION

The present patent relates to plate heat exchangers and in particular concerns a new compact multi-circuit exchanger unit, particularly for the installation of units of the HIU ("Heat Interface Unit") type.

HIUs are interface units normally installed in large complexes where there are numerous separate users or residential units.

Each user, instead of being served by its own dedicated boiler, is connected to a central boiler, or central heating plant, which supplies thermal energy to the entire complex both for heating and for the production of domestic hot water. An interface unit connects the central heating plant with the domestic hot water and heating systems of each user. Therefore, it is not necessary to equip each user with its own energy source, rather, on the contrary, a single supply between the heating plant and each user is sufficient.

Moreover, it is no longer necessary to install a network of gas pipes in the building leading to each of the residential units and therefore it is not obligatory to provide ventilation openings for possible gas leaks in the premises of each user. As a result, the entire system is structurally simpler, that is, the installation and subsequent maintenance operations are simplified.

The use of these interface units in high efficiency energy systems that use energy sources of various types such as solar energy, heat pump, district heating, etc. is well known in the prior art.

The interface units generally comprise a plate exchanger to transfer energy from a primary system fluid, which for example is sent and used in the building heating system, and a secondary fluid, normally used in the domestic hot water supply system.

The domestic hot water is therefore produced in an indirect way and sent to the users instantly, upon request, without requiring any storage of hot water.

Interface units are known where the water for heating is also produced indirectly by a specially dedicated plate heat exchanger, with the advantage of completely separating each user's system from the central system. For example, there are known interface units comprising two separate exchangers, comprising a first exchanger, for the exchange between the primary fluid of the system and the fluid to be sent to the heating, and a second exchanger physically separate and independent of the first, for the exchange between the same primary fluid of the system and the water to be sent to the domestic hot water system.

Thus the primary fluid coming from the thermal power plant enters this unit and, through dedicated valves, is normally sent to the first exchanger for heating, while, at the request of the user, it is totally or partially diverted towards the second exchanger for the production of domestic hot water.

Generally, an electronic regulator controls the opening/closing of the valves.

The interface units of the known type with two exchangers have some drawbacks: given the need to install two separate exchangers, both individually served by the main manifold, it is also necessary to install valves and regulators which, in addition to making the unit technically and hydraulically complex, involve delays in the instantaneous supply of domestic hot water.

Prior art includes plate heat exchangers comprising at least two separate circuits respectively for the circulation of a primary fluid and a secondary fluid, where those circuits are defined by a plurality of exchange plates with facing surfaces, featuring ridges and grooves, generally distributed in a herringbone pattern.

The object of the present patent is a new compact multi-circuit exchanger unit, especially for the installation of HIU type units.

The main object of the present invention is to have a compact shape which requires, compared to known systems, a smaller space for its installation inside the interface unit, since it integrates the function of at least two exchangers in a single body, one for the heating system and one for the domestic hot water system.

Another object of the present invention is the use of a smaller number of pipes connecting the exchanger with respect to the currently known systems.

Yet another object of the present invention is a single regulation of the primary fluid entering the exchanger, thus reducing the number of regulating valves normally present in a HIU unit.

Still another object of the present invention is to reduce to a minimum the waiting times for the supply of domestic hot water.

A further object of the present invention is to be dimensioned and shaped according to the installation requirements, such as position, dimensions, and so on.

One advantage of the present invention is that it is able to be sized according to the plant requirements, for example in a symmetrical way, that is, where the exchange surface to heat the heating fluid is substantially equal to the exchange surface to heat the domestic hot water system fluid, or asymmetrically.

It is in fact also possible for the exchange surface between the primary fluid and the heating fluid to be different from the exchange surface between the primary fluid and the domestic hot water system fluid.

The two distinct areas of the heat exchanger designated for the heat exchange between the primary system fluid and each of the fluids of the heating and domestic hot water systems may have specific and predetermined performance characteristics, with regard to thermal yield, hydraulic resistance, or pressure loss.

The exchanger plates may also be specially shaped so that the primary fluid circuit has different characteristics than the two secondary fluid circuits of the systems.

It is therefore possible to combine the plates forming the exchanger so as to optimize the performances relative to the circuits of the three fluids.

One advantage of the present invention is that it maximizes energy efficiency.

These and other aims, direct and complementary, are achieved by the new compact multi-circuit exchanger unit, particularly for the installation of units of the HIU ("Heat Interface Unit") type.

The new exchanger unit is of the plate type and comprises a single plate pack facing each other and welded in a manner known in the prior art and with passage holes to define: • a first circuit of a primary fluid, for example coming from a thermal source, suited to yield heat, which circulates between alternating pairs of the facing plates of the entire plate pack; • a second circuit of a first secondary fluid, suited to receive heat from the primary fluid, wherein the second circuit is limited to a first area of the plate pack, that is, the first secondary fluid circulates between a part of pairs of the facing plates, alternating with the pairs between which the primary fluid circulates;

• a third circuit of a second secondary fluid, suited to receive heat from the primary fluid, wherein the third circuit is limited to a second area of the plate pack different from the first area, that is, the second secondary fluid circulates between a part of pairs of the facing plates alternating with the pairs between which the primary fluid circulates;

the first, second and third circuits being hydraulically isolated from each other.

In a preferred embodiment, the second and third circuit can be arranged side by side or adjacent to each other, where the plates for the circulation of the fluids are in turn divided into two adjacent areas, one destined for the circulation of the first secondary fluid, where the exchange with the primary fluid occurs, and one destined for the circulation of the second secondary fluid, where the exchange with the primary fluid takes place, and where the areas are in any case hydraulically isolated from each other.

In a possible alternative embodiment, the second and third circuit can be arranged on top of each other in the exchanger assembly, that is so that in a first area of the plate pack the exchange between the primary fluid and the first secondary fluid occurs, while in a the second area of the plate pack the exchange between the primary fluid and the second secondary fluid takes place.

This second embodiment is ideally obtainable from the first configuration by rotating the second area by 180° and superimposing it on the first area, thus obtaining a different geometry with the same functionality.

This configuration is especially obtainable with plates of the known type.

The new exchanger unit therefore enables the use of a single primary exchange fluid to disperse heat, inside a compact exchanger body, to two separate secondary fluids, wherein no heat exchange takes place between the first and second secondary fluids.

In particular, the circuits may be arranged so that the thermal exchange, for example in countercurrent, takes place first between the primary fluid and the first secondary fluid, for example intended to then be sent/used in a domestic hot water system, then the heat exchange, for example in countercurrent, between the first primary fluid and the second secondary fluid, for example destined to then be sent/used in a heating system.

The characteristics of the new system will be better clarified by the following description with reference to the drawings, attached by way of a non-limiting example.

Figure 1 schematically shows the new exchanger unit (1) in a first embodiment with adjacent areas (A, B).

Figure 2 schematically shows the two plates (10, 10') of the new exchanger unit usable for the embodiment with adjacent areas in Figure 1, with ridges and depressions inverted between one plate and the other.

Figure 3 schematically shows the new exchanger unit (Γ) in a second embodiment with superimposed areas (Α', Β') or as a "pack".

The new exchanger unit (1) is of the type with plates (10, 10') facing each other, provided with ridges and depressions, generally distributed in a herringbone pattern, welded in a manner known in the prior art and provided with holes for the passage of system fluids, and where in the spaces between pairs of plates (10, 10') facing each other the circuits or paths (11, 12, 13) for the circulation of the system fluids (C, W, H) are identified. These circuits (11, 12, 13) are hydraulically isolated from each other.

Said at least three circuits (11, 12, 13) of the new exchanger unit (1) are integrated in a single pack of pairs of facing plates (10, 10'), having ridges and depressions arranged so as to identify the areas where the exchange occurs and where it does not.

In particular, between said plates (10, 10') a first circuit (11) of a primary fluid (C) is identified, for example coming from a thermal source, able to transfer heat. This primary fluid (C) comes, for example, from a district heating plant.

Said primary fluid (C) circulates in said first circuit (11) identified between alternate pairs of the facing plates (10, 10') of the entire plate pack.

Said first circuit (11) comprises at least one inlet area (Hi) for the introduction of said primary fluid (C), coming from a source plant, and at least one outlet area (l lu) for the return of the primary fluid (C) to said source plant.

In the embodiments shown in Figures 1 and 2, the new exchanger assembly (1) comprises two types of plates (10, 10') arranged alternately, such that, as shown in Figure 2, the first circuit (11) is formed from their coupling which involves the entire surface of the plates, and a second and a third circuit (12, 13) which involve two adjacent areas (A, B) of the plates, these adjacent areas (A, B) being hydraulically isolated from each other. In particular, the second and third circuits (12, 13) are obtained by coupling two different plates (10, 10') where one face of one of said plates (10') comes in contact with said primary fluid (C), which runs through the inner surface, while the opposite face is in turn divided into two adjacent areas (10a, 10b) as shown in Figure 2: a first area (10a) intended for the circulation of the first secondary fluid (W) and a second area (10b) intended for the circulation of the second secondary fluid (H), where the adjacent areas (10a, 10b) are in any case hydraulically isolated from each other.

Said plates (10, 10') can have dimensions, geometries and hydraulic characteristics such as to be able to differentiate the performance of each circuit (11, 12, 13) according to the needs of the system. This therefore makes it possible to construct a single exchanger assembly in which the three hydraulic circuits each have the required characteristics. In the embodiment in Figures 1 and 2, the two areas (A, B) of the exchanger (1) and said two adjacent areas (10a, 10b) of each plate (10') are substantially symmetrical. Alternatively, it is in any case possible for said two areas (A, B) of the exchanger (1) and said two areas (10a, 10b) of each plate (10') to be asymmetric.

In said second circuit (12) a first secondary fluid (W) circulates, suited to receive heat from said primary fluid (C). Said first secondary fluid (W) is, for example, water directed to a domestic hot water system.

Said second circuit (12) is limited to the first area (A2) of said plate pack (10, 10'), that is, said first secondary fluid (W) circulates between the facing plates (10, 10'), alternating with said pairs between which said primary fluid (C) circulates, only in correspondence with the first area (10a) of each plate (10').

Said second circuit (12) comprises at least one inlet area (12i) for the introduction of said first secondary fluid (W), for example coming from a domestic hot water system, and at least one outlet area (12u) for the return of said first secondary fluid (W) to the domestic hot water system.

Thus in said first area (A) there is the thermal exchange between said primary fluid (C), which enters at high temperature in the first circuit (11), and said first secondary fluid

(W) which, during circulation in said second circuit (12) absorbs heat.

In the embodiment shown in Figure 1, the circulation of said primary fluid (C) and of said first secondary fluid (W) is co-current, but may also be counter-current.

A second secondary fluid (H) circulates in said third circuit (13), suited to receive heat from the primary fluid (C). Said second secondary fluid (H) is, for example, water directed to a heating system.

Said third circuit (13) is limited to said second area (B) of said plate pack (10, 10'), that is, said first secondary fluid (W) circulates between said facing plates (10, 10'), alternating with said pairs between which said primary fluid (C) circulates only at said second area (10b) of each plate (10').

Said third circuit (13) comprises at least one inlet area (13i) for the introduction of said second secondary fluid (H), for example coming from a heating system, and at least one outlet area (13u) for the return of said second secondary fluid (H) to said heating system. In said second area (B) the heat exchange takes place between said primary fluid (C), which comes from said first area (A), and said second secondary fluid (H) which, during circulation in said third circuit (13) absorbs heat.

In the embodiment shown in Figure 1, the circulation of said primary fluid (C) and of said second secondary fluid (H) is counter-current, but it may also be co-current.

Each of the plates (10, 10') of the new exchanger assembly (1) therefore comprises a first face destined to come into contact with said primary fluid (C), where the ridges and depressions are arranged so that the contact substantially affects the entire surface of the first face. For this purpose, said plates (10, 10') comprise passage holes (111, 112) for said primary fluid (C), for example, arranged near the edges of the plate (10, 10'), normally at the corners. Each plate (10, 10') then comprises the opposite face intended to come into contact with said first secondary fluid (W) in said first area (10a) and with said second secondary fluid (H) in said second area (10b). Said first area (10a) and said second area (10b) are for example two areas separated from each other by a transverse axis (X) with respect to the overall length of the plate (10, 10').

Said ridges and depressions on the plates (10, 10') are then arranged so that said second circuit (12') of said first secondary fluid (W) and said third circuit (13') of said second secondary fluid (H) remain hydraulically isolated from each other. For this purpose, said plates (10, 10') comprise further passage holes (121, 122) for said first secondary fluid (W) arranged on the first area (10a), and further passage holes (131, 132) for said second secondary fluid (H) arranged on said second area (10b).

In the embodiment shown in Figure 2, said two areas (10a, 10b) are substantially symmetrical with respect to the central transverse axis (X) of said plate (10, 10'). However said areas (10a, 10b) may have different dimensions, geometries and hydraulic characteristics, depending on the needs of the plant.

In the embodiment shown in Figure 3, said two areas (Α', Β') are superimposed on each other and the first circuit (1 Γ) involves both of said areas (Α', Β'): these two areas (Α', Β') are subdivided by means of a partition plate (20) provided with passage holes (21) for the passage of the primary fluid (C) from the first area (Α') to the second area (Β').

In this case, the plates (10) used may suitably be of the known type, with holes arranged so as to form the three hydraulically isolated circuits (1 Γ, 12', 13').

Said first circuit (1 Γ) comprises at least one inlet area (l l'i) for the introduction of said primary fluid (C), coming from a source plant, and at least one outlet area (l l'u) for the return of the primary fluid (C) to the source plant.

In said exchanger assembly (Γ) a second circuit (12') of a first secondary fluid (W) is also identified, suitable to receive heat from the primary fluid. Said first secondary fluid (W) is, for example, water directed to a domestic hot water system.

Said second circuit (12') is limited to the first area (A) of said plate pack (10), that is, said first secondary fluid (W) circulates between said pairs of facing plates (10) of said first area (Α'), alternating with the pairs between which said primary fluid (C) circulates. Said second circuit (12') comprises at least one inlet area (12'i) for the introduction of said first secondary fluid (W), for example coming from a domestic hot water system, and at least one outlet area (12'u) for the return of said first secondary fluid (W) to the domestic hot water system.

In said first area (Α') the heat exchange takes place between said primary fluid (C), which enters said first circuit (1 Γ) at a high temperature, and said first secondary fluid (W) which, during circulation in said second circuit (12') absorbs heat.

In the embodiment shown in Figure 3, the circulation of said primary fluid (C) and of said first secondary fluid (W) is co-current, but it may also be in counter-current.

In said exchanger assembly (Γ) a third circuit (13') of a second secondary fluid (H) is also identified, suitable to receive heat from said primary fluid (C). Said second secondary fluid (H) is, for example, water directed to a heating system.

Said third circuit (13') is limited to said second zone (Β') of the plate pack (10), that is, said second secondary fluid (H) circulates between the pairs of facing plates (10) of the second zone (B), alternating with the pairs between which the primary fluid (C) circulates.

Said third circuit (13') comprises at least one inlet area (13'i) for the introduction of said second secondary fluid (H), for example coming from a heating system, and at least one outlet area (13'u) for the return of said second secondary fluid (H) to the heating system. In said second zone (Β') there is the thermal exchange between the primary fluid (C), which comes from said first zone (Α'), and the second secondary fluid (H) which, during circulation in said third circuit (13') absorbs heat.

In the embodiment shown in Figure 3, the circulation of said primary fluid (C) and of said second secondary fluid (H) is counter-current, but it may also be co-current.

The exchanger assembly (1, Γ), both in the embodiment shown in Figure 1 and in the embodiment shown in Figure 3, is also suitably provided with means suited to open/close at least one of the circuits according to the requirements of the plants.

Under normal conditions, said second circuit (12) may be normally closed, when there is no demand for domestic hot water, that is, there is no heat absorption in said first zone (A) of the exchanger (1). Said primary fluid (C) therefore releases heat only to said second secondary fluid (H), in said second zone (B).

Upon request for hot water, said second circuit (12) is opened, so that said primary fluid (C) releases heat first to said first secondary fluid (W) and then to said second secondary fluid (H).

It is also possible that when said second circuit (12) is open, said third circuit (13) may be closed.

These specifications are sufficient for the expert person to construct the assembly of the invention, as a result, in the practical application there may be variations without prejudice to the substance of the innovative concept.

Therefore, with reference to the preceding description and the attached drawings the following claims are made.