Heat exchanger for heat recovery ventilation systems

Abstract

A heat exchanger for ventilation systems with heat recovery made of a quadrangular cross-section and longitudinal channels with a diamond-shaped cross-section formed by interconnected plates, provided with means for distributing exhaust and intake air flows, characterized in that the heat exchanger body is theoretically divided into a central part in which the heat exchanger channels have a wave-like shape along their entire length, and outer parts in which the heat exchanger channels serving as means for distributing exhaust and intake air are internally straight along their entire length, have a zigzag cross-section and are open at the end, while the outer channels (7) adjacent to two opposite side surfaces of the heat exchanger and the end parts of the heat exchanger channels (8) are alternately open and sealed in such a way that each group of open channels (7,8) on one outer part of the heat exchanger is sealed to the opposite outer part, and the heat exchanger body is placed inside a housing containing longitudinal slots corresponding to the size and position of the open channels (7, 8).,

Description

[0001] Heat exchanger for ventilation systems with heat recovery

[0002] Field of technology

[0003] The invention relates to mechanical ventilation technology for rooms, in particular to heat exchangers used in ventilation devices with heat recovery.

[0004] Such heat exchangers, as a component of the ventilation system, are used to transfer thermal energy from the exhaust flow (exhaust air is removed from the room) to the supply flow (fresh air is supplied to the room).

[0005] It is known that modern construction is focused on insulation and sealing of premises to reduce the overall energy costs for heating and cooling the indoor air. Thus, due to the sealing of premises, infiltration (natural supply of outside air due to leaks) is virtually completely stopped, which in turn makes the process of natural ventilation impossible.

[0006] In addition, building codes and regulations require sufficient air exchange in the room to ensure sufficient fresh air and oxygen supply to the room for people to stay in healthy and comfortable conditions. Under these circumstances, mechanical ventilation is a reliable means of achieving the required air exchange. However, mechanical ventilation increases energy costs in the room due to the need to heat / cool the incoming (fresh outside air). The task of ensuring the required air exchange, with the minimum possible energy costs, is performed by ventilation devices with heat recovery.

[0007] In essence, ventilation with recuperation is necessary to remove exhaust air from the room, along with excess moisture, carbon dioxide, other products of human activity with possible internal pollutants, and to supply fresh outside air to the room, with minimal energy costs for its heating due to the exchange of thermal energy occurring in the heat exchanger.

[0008] At the moment, heat exchangers of various sizes and shapes are widespread, used in ventilation systems with heat recovery, which contain longitudinal channels inside, through which air flows move in opposite directions, namely: from the room to the outside - polluted (exhaust) air, and from the outside to the room - fresh (supply) air. Due to the presence of movement of the mentioned air flows, parallel in opposite directions, in the heat exchanger channels, through heating / or / cooling of adjacent channel walls, heat is transferred from one air flow to another, due to which, in turn, recovery is carried out - heat exchange between opposite air flows, which allows using the energy already spent on cooling / heating the supply air into the room again.

[0009] Heat exchangers of this type contain in their design means for distributing exhaust and supply air in the heat exchanger channels; such means can be different types of covers, dampers, plugs on the remote (opposite) sides of the heat exchanger.

[0010] Prior art

[0011] A "Device for cooling and / or heat recovery" is known from the prior art, comprising several heat exchanger modules configured to be connected, each containing one heat exchanger and connected to ensure the operation of their heat exchangers according to a parallel connection scheme, characterized in that each heat exchanger module has a housing surrounding the heat exchanger, which has one inlet and one outlet opening for air on the end faces, as a result of which each of the successive heat exchanger modules has two inlet and two outlet openings for air, and the device comprises a common supply air duct and a common exhaust air duct connected to the heat exchanger modules to ensure the possibility of uniform and parallel supply of the air inlet openings of the successive heat exchanger modules with exhaust air from the common exhaust air duct,as well as uniform and parallel outlet of supply air from the air outlet openings of the heat exchanger modules following one another into a common supply air duct (patent RU0002671766).

[0012] The disadvantages of this device are the complexity of its design, low efficiency and large dimensions;

[0013] Also known are plate heat exchangers containing finned plates assembled into a pack to form channels (Patent UA No. 2254532 C2. Plate heat exchanger. - IPC6 F28D 9 / 00. - Published 2005.06.20; Patent RU36C224. Plate heat exchanger. - IPC6 F28D 9 / 00. - Published 2004.12.10).

[0014] Despite the simpler design than the above-mentioned “Device for cooling and / or heat recovery” (Patent RU0002671766), the disadvantage of these heat exchangers is their low heat exchange intensity.

[0015] The closest analogue to the proposed invention is a heat exchanger, which contains the "Ventilation system with heat recovery" (Patent of Ukraine No. 150073), where the heat exchanger of the mentioned system has a rectangular shape, is made of copper plates connected to each other in the shape of a rhombus, and contains means for distributing supply and exhaust air, which are openings that are alternately open and closed, located on round covers located on the end parts of the heat exchanger.

[0016] In this heat exchanger, the flows of incoming and outgoing air move along the channels formed by its plates, which are connected to each other. The distribution of air flows along the corresponding channels is carried out by means of distributing incoming and outgoing air, which are round covers placed on the end parts of the heat exchanger, containing round openings.

[0017] In such a “Heat Recovery Air Ventilation System”, the heat exchanger is mounted inside the housing, where further air distribution is carried out by means of the structural elements of the device itself (the ventilation system).

[0018] In this case, the intake (pulling) of air into the heat exchanger both from outside the room and from inside the room is carried out through the gaps between the inner surface of the ventilation system body, and the outlet (release) is through cylindrical air ducts (pipes) inside the ventilation system.

[0019] Despite its compactness, ease of manufacture and improved heat exchange performance compared to the above-mentioned heat exchangers, the disadvantage of the closest analogue is its insufficient air contact with the surface area of ​​the heat exchanger channels, due to which heat exchange is insufficient. In addition, the means for distributing exhaust and supply air flows, which are located on its remote sides - covers, as separate design elements are difficult to manufacture, increase the dimensions of the ventilation system and are included in the heat recovery process only as means for distributing air flows. Disclosure of the invention

[0020] The objective of the proposed invention is to improve the heat exchange of the heat exchanger, simplify both its design and the means for distributing exhaust and supply air, and simplify the production of the heat exchanger.

[0021] The stated problem is solved by the fact that in a heat exchanger for ventilation systems with heat recovery, made in a cross-section in the form of a quadrangle, with longitudinal diamond-shaped channels in the cross-section, which are formed from interconnected plates, and equipped with means for distributing flows of exhaust and supply air, it is proposed to make the channels in its middle part wavy along their length, and in the extreme parts, in which the channels serve as means for distributing exhaust and supply air, in the middle to make them straight along the length, zigzag in cross-section and open, wherein the outer channels bordering two opposite side surfaces of the heat exchanger and the end parts of the channels of the heat exchanger are proposed to be made alternately open and sealed in such a way that each group of open channels of one extreme part of the heat exchanger would be sealed on the opposite extreme part of the heat exchanger,the body of the heat exchanger is proposed to be placed in a casing containing longitudinal slots corresponding to the dimensions and location of the open channels of the heat exchanger.

[0022] The technical result of the proposed invention is an improvement in heat exchange performance, a simplification of the heat exchanger design, including means for distributing exhaust and supply air, and the heat exchanger is simpler to manufacture.

[0023] The above is confirmed by tests of the proposed heat exchanger, in particular, comparative results of the proposed heat exchanger and the closest analogue showed that the efficiency coefficient (EC) of the proposed heat exchanger is 10-15% higher than the indicators of the closest analogue.

[0024] Brief description of the invention drawings

[0025] The essence of the invention is explained in the drawings Figures 1-6, where the components of the device are observed, in all the attached graphic materials, namely:

[0026] 4 Fig. 1. Heat exchanger body;

[0027] Fig. 2. A pair of plates that form the heat exchanger channels;

[0028] Fig.3. Top view of the heat exchanger;

[0029] Fig. 4. Schematic representation of the distribution of heat exchanger parts;

[0030] Fig. 5. Schematic representation of the location of the heat exchanger in the ventilation system and the principle of air flow distribution;

[0031] Fig. 6. Heat exchanger casing; where the above-listed Figures of drawings 1-6 show:

[0032] 1 - heat exchanger;

[0033] 2 - heat exchanger plates;

[0034] 3 - middle part of the heat exchanger;

[0035] 4 - heat exchanger channels in the middle part;

[0036] 5 - extreme parts of the heat exchanger;

[0037] 6 - heat exchanger channels in the extreme parts;

[0038] 7 - external channels of the extreme parts of the heat exchanger, bordering the side surfaces of the heat exchanger;

[0039] 8 - end parts of heat exchanger channels;

[0040] 9 - heat exchanger casing;

[0041] 10 - heat exchanger casing partitions;

[0042] 11 - heat exchanger casing gaps;

[0043] 12 - ventilation system supply air fan;

[0044] 13 - exhaust air fan of the ventilation system;

[0045] 14 - ventilation system air duct;

[0046] 15 - external cover of the ventilation system;

[0047] 16 - outer side of the wall;

[0048] 17 - the space between the inner surface of the ventilation system housing and the outer surface of the air duct;

[0049] 18 - central opening of the ventilation system cover from the room side;

[0050] 19 - inner cover of the ventilation system;

[0051] 20 - inner side of the wall;

[0052] 21 - central hole of the ventilation system cover from the outside; As can be seen from the drawings in Figures 1-6, the heat exchanger for ventilation systems with heat recovery (1), made in a cross-section in the form of a quadrangle, with longitudinal diamond-shaped channels in the cross-section, which are formed from interconnected plates (2), the body of the heat exchanger is conditionally divided into a middle part (3) where the channels are wavy along their length (4) and extreme parts (5), in which the channels of the heat exchanger (6), serving as means for distributing exhaust and supply air, are straight along the length inside, zigzag in cross-section and open, and the outer channels (7) bordering two opposite side surfaces of the heat exchanger and the end parts of the channels of the heat exchanger (8) are alternately open and sealed in such a way that each group of open channels (7,8) of one extreme part of the heat exchanger is sealed on the opposite extreme part of the heat exchanger.

[0053] The dimensions of the middle part (3) and the outer parts (5) of the heat exchanger body may be equal or different depending on the technical characteristics of the ventilation system in which the heat exchanger (1) is mounted.

[0054] The body of the heat exchanger is located in the casing (9) and contains longitudinal slots (11) corresponding to the dimensions and location of the open external channels of the heat exchanger (7), bordering the side surfaces of the heat exchanger and the open end parts of the channels of the heat exchanger (8).

[0055] Considering that most decentralized ventilation systems with heat recovery have a rounded casing in cross-section, and the heat exchanger has a quadrangular cross-section, there is a need to prevent mixing of air flows inside the ventilation system casing, as well as air leaks outside the heat exchanger into the process channels of the ventilation system. In the absence of such means in the design of the ventilation system, the heat exchanger casing can be equipped with at least one transverse partition (12) on its outer surface within the middle part of the heat exchanger.

[0056] Also, the transition of the shape of the heat exchanger channels from its middle part (4) (where the channels are wavy in length) to the shape of the channels in its extreme parts (5) (where the channels are straight in length, zigzag in cross-section and open) can have a wedge shape (Fig. 1-3). Such a wedge-shaped transition of the shape of the heat exchanger channels increases the heat exchange area in the heat exchanger without losing the intensity of the movement of air flows when air enters and passes through open external channels bordering two opposite side surfaces of the extreme parts of the heat exchanger (b), and therefore the extreme parts of the heat exchanger perform not only the function of means for distributing supply and exhaust air, but also take part in the heat exchange process.

[0057] Embodiment of the invention

[0058] The device works as follows.

[0059] During operation, the heat exchanger is installed in the housing of the ventilation system, which in turn is installed in the opening in the wall of the room to be ventilated.

[0060] When the working fans (12,13) ​​of the ventilation system are mechanically driven, both the supply and exhaust air passes through the ventilation system itself and through the heat exchanger itself. The end faces of the heat exchanger are in contact with the air ducts (14) of the ventilation system with the supply and exhaust air fans (12, 13) built into them.

[0061] The passage of supply and exhaust air both through the ventilation system and through the heat exchanger itself occurs as follows:

[0062] 1. supply air from outside the room (when the supply air fan (12) is turned on, under the action of its blades, it is drawn in through the slots in the outside air intake of the external cover of the ventilation system (15) located on the outside of the wall (16).

[0063] Then the supply air passes through the space between the inner surface of the ventilation system body and the outer surface of the ventilation system air duct (14), after which the supply air is drawn into the heat exchanger channels through the open external channels (inlet) (7) of the extreme part of the heat exchanger (5) bordering the side surface of the heat exchanger. Passing through the heat exchanger channels, the air is heated / cooled and exits through the open end parts of the channels (outlet) (8) on the opposite side of the heat exchanger and through the ventilation system air duct (14) on the opposite side; the supply air is supplied to the room through the central opening of the ventilation system cover (18) from the room side; 2. simultaneously, the exhaust air from inside the room (when the exhaust air fan (13) is turned on), under the action of its blades, is drawn in through the slots of the internal air intake of the internal cover (19) located on the inner side of the wall (20).Next, the exhaust air passes through the space between the inner surface of the ventilation system housing and the outer surface of the air duct (16), after which, through the open external channels (inlet) (7) of the extreme part of the heat exchanger, bordering the side surface of the heat exchanger (5), the exhaust air is drawn into the channels of the heat exchanger, passing through the channels of the heat exchanger, is heated / cooled and exits through the end parts of the channels (outlet) of the heat exchanger (8) on the opposite side and through the air duct (14) exits outside the room (into the environment) through the central opening of the cover of the ventilation system on the outside (21);.

[0064] Industrial batches are planned for release by Lviv plants in the 4th quarter of 2023.

Claims

Formula 1. A heat exchanger for ventilation systems with heat recovery (1), made in a cross-section in the form of a quadrangle, with longitudinal diamond-shaped channels in the cross-section, which are formed from interconnected plates (2) and equipped with means for distributing the flows of exhaust and supply air, is characterized in that the body of the heat exchanger is conditionally distributed into a middle part (3) where the channels of the heat exchanger (4) are wavy along their length and extreme parts (5), in which the channels of the heat exchanger (b), serving as means for distributing the exhaust and supply air, are straight along the length inside, zigzag in cross-section and open, and the outer channels (7) bordering two opposite side surfaces of the heat exchanger and the end parts of the channels of the heat exchanger (8) are alternately open and sealed in such a way that each group of open channels (7,8) of one extreme part of the heat exchanger is sealed on the opposite extreme part of the heat exchanger,the body of the heat exchanger is placed in a casing (9) containing longitudinal slots (11) corresponding to the dimensions and location of the open channels (7,8)., 2. A heat exchanger for ventilation systems with heat recovery according to paragraph 1. is characterized in that the heat exchanger casing (9) contains at least one transverse partition (10) on its outer surface within the middle part of the heat exchanger.

3. The heat exchanger for ventilation systems with heat recovery according to paragraph 1 is distinguished by the fact that the transition of the shape of the channels (4,6) of the heat exchanger from the middle part (3) of the heat exchanger to the extreme parts (5) of the heat exchanger has a wedge-shaped form. 9