HEAT TRANSFER ARRANGEMENT FIELD OF THE INVENTION [0001] The invention relates to a heat transfer device for changing the temperature inside a vehicle, comprising at least one heat transfer element having at least one fluid channel for the flow of a fluid medium; at least one pump connected to the fluid channel for circulating the fluid medium through the heat transfer element ; at least one heating/cooling unit for changing the temperature of the fluid medium; a cover which surrounds the heat transfer element and inside which cover there is at least one air channel; at least one blower for generating an air flow in the air channel ; at least one flow opening through which air flowing in the air channel is arranged to discharge to the outside of the cover; and at least one narrow opening through which the air flowing from the air channel to the flow opening is arranged to flow.

[0002] Further, the invention relates to a heat transfer element for changing the temperature inside a vehicle, which heat transfer element comprises: at least one fluid channel; a cover surrounding the heat transfer element; at least one longitudinal air channel for conducting the air flow of the air channel from a first end of the heat transfer element to a second end thereof; at least one flow opening connected to the air channel, allowing at least partial discharge of the air flow to the outside of the cover; and at least one narrow opening, which is arranged between the flow opening and the air channel and through which the discharging air flow is arranged to flow.

[0003] Furthermore, the invention relates to a heat transfer method for a vehicle, which method utilizes a heat transfer device comprising at least one heat transfer element, at least one pump, and at least one heating/cooling unit, the method comprising circulating a fluid medium by means of the pump in a fluid channel in the heat transfer element; affecting the temperature of the fluid medium by means of the heating/cooling unit; generating an air flow in an air channel inside the cover of the heat transfer element ; and conducting at least part of the air flow through at least one narrow opening in the heat transfer element and further through at least one flow opening connected to the narrow opening to the outside of the cover.

BACKGROUND OF THE INVENTION [0004] Radiators are typically used for adjusting the temperature of passenger cabins in vehicles, such as buses, which radiators comprise a fluid

channel for conducting a heating fluid through the radiator, and fins arranged around the fluid channel to increase the heat-transferring surface of the radiator. A flow may be conducted through the radiator either in one direction, or the heating system may be connected as a closed loop in such a way that also the returning fluid flow travels through the radiator. In a bus, radiators of this type are usually arranged below the windows, in the passenger legroom.

The problem is that in the cold weather the heat does not rise sufficiently to heat wall and window surfaces, whereby the cold wall surface feels uncomfortable, and water vapour may gather on the vehicle windows. Raising the radiator temperature is not a solution, because hot radiators feel uncomfortable in the passenger legroom and can even cause injuries. In addition, dust and other dirt smoke on the surface of a hot radiator.

BRIEF DESCRIPTION OF THE INVENTION [0005] An object of the present invention is to provide an improved heat transfer arrangement of a new type.

[0006] A heat transfer device according to the invention is characterized in that the heat transfer element comprises a labyrinth-like structure having several successive narrow openings of different directions through which the air flowing from the air channel to the flow opening is arranged to flow ; and that the narrow openings of the labyrinth-like structure are dimensioned in such a way that the flow velocity of the air flow discharging from the flow opening is higher than the flow velocity in the air channel.

[0007] A heat transfer element according to the invention is characterized in that the heat transfer element comprises a labyrinth-like structure having several successive and narrow openings of different directions.

[0008] A heat transfer method according to the invention is characterized by directing at least part of the air flow through the successive narrow openings of different directions in the labyrinth-like structure in the heat transfer element; and directing the discharging air flow from the flow opening to the wall surface, the wall surface being arranged to function as a heat-radiating surface.

[0009] An essential idea of the invention is that a fluid medium flow is conducted through at least one fluid channel in the heat transfer element, and an air flow is conducted through an air channel in the heat transfer

element in the longitudinal direction of the element. The heat transfer element further comprises at least one flow opening, through which air heated or cooled in the element is allowed to flow out of the space limited by the element cover.

The flow opening directs the discharging air flow in a desired manner. The air flow to be conducted from the air channel to the flow opening is arranged to flow through at least one narrow opening in such a way that the air discharging out of the flow opening has a higher flow velocity than the air flowing in the air channel. When the flow velocity increases, the heat transfer from the surfaces limiting the narrow opening becomes more efficient.

[0010] The heat transfer element according to the invention may be rather small with regard to its outer dimensions, but it can still be very efficient.

Owing to its small size, it is easier than before to arrange in vehicle structures, for example. Further, the heat transfer element according to the invention is light, which is an important feature in vehicle constructions. By means of an air jet heat can be transferred farther away from the element than previously.

Thus, the air jet can be directed from the flow opening to the wall surface of a vehicle body, for instance, whereby the wall is heated and functions thus as a comfortable and large heat-transferring surface. Since the outer surface of the heat transfer element is not heated significantly when the inside of the vehicle is heated, the element according to the invention is comfortable to the passengers. Further, for instance compared with previous radiators constructed of several fin plates, the heat transfer element according to the invention has a simple structure, owing to which it is easier and cheaper to manufacture.

[0011] An essential idea of an embodiment of the invention is that there are fins inside the cover of the heat transfer element, which fins increase the surface area and form a labyrinth-like structure. The air flow to the flow opening is arranged to travel through several successive narrow openings in the labyrinth-like structure. Thus, the flow velocity of the air flow increases in the labyrinth-like structure, making the heat transfer between the air flow and the fins more efficient. Further, the fins are arranged in such a way that the labyrinth-like structure changes the direction of the air flow, generating turbulence in the flow, which further improves the heat transfer.

[0012] An essential idea of an embodiment is that a large number of very small openings have been formed in the cover of the heat transfer element by means of a laser, for instance, the discharging air flow being

conducted through the openings. The openings can be positioned in such a way relative to each other that they form a desired blow pattern.

[0013] An essential idea of an embodiment of the invention is that the size of the flow opening can be adjusted. Hereby, the air flow discharging out of the heat transfer element can be adjusted over the length of the heat transfer element in such a way that a discharging air flow of precisely the correct size is provided for the desired objects, for example windows. At some points, mere heat radiation through the element cover is sufficient, whereby the flow openings can at these points be completely closed. Further, when the heat transfer line is long, and limited blowing output is supplied to it, controlling the discharging air flow makes it possible to ensure that a sufficient air flow is achieved also through the flow openings far away from the air supply point.

[0014] An essential idea of an embodiment of the invention is that the flow opening is an elongated discharge opening in the longitudinal direction of the heat transfer element. Thus, the discharging air flow generates a broad air curtain, which allows, for instance, effective prevention of vapour generation on the window surface of a vehicle or reduction of draught.

[0015] An essential idea of an embodiment of the invention is that the heat transfer element is an integrated part formed in one step by extruding, comprising at least a cover, fins, a fluid channel and an air channel.

Manufacturing such a profile by extruding is cost-effective. It is not necessary to have separate components in the element structure. Upon installation of the heat transfer device, it is quick and handy to cut elements according to the needs of the object of use from the extruded profile and to connect them to the supply channels of the fluid medium and air.

[0016] An essential idea of a sixth preferred embodiment of the invention is that the heat transfer element is extruded in one piece in an open form, whereby the extrusion tool can be simpler. In addition, the extrusion process is easier to implement. A hinge member, such as a thinned portion, is provided in the cover of the heat transfer element, which member joins the opened halves to each other and allows closing of the halves against each other after the extrusion.

[00171 An essential idea of a seventh preferred embodiment of the invention is that the heat transfer element comprises a first half and a second half manufactured separately, the halves being connectable to each other to form a continuous cover. A fluid channel has been integrated in at least one of

the halves. Further, the first and the second half together limit the air channel.

Assembling the element from halves manufactured separately facilitates extrusion. In addition, halves having different structures and appearances can be formed, and combining such halves allows manufacturing of elements having different properties. For instance, the number of fins and the number and position of fluid channels may vary. Thus, the elements may have the advantages of a module structure.

BRIEF DESCRIPTION OF THE FIGURES [0018] The invention will now be described in more detail with reference to the attached drawings, of which [0019] Figure 1 is a schematic view of a heat transfer device according to the invention; [0020] Figure 2 is a schematic view of a second heat transfer device according to the invention; [0021] Figure 3 is a schematic cross-sectional view of a heat transfer element according to the invention; [0022] Figure 4 is a schematic end view of a second heat transfer element according to the invention, the parts being drawn apart; [0023] Figure 5 is a schematic end view of an element half which can be applied to the structure of Figure 4; [0024] Figure 6 is a schematic end view of a third heat transfer element according to the invention; [0025] Figure 7 is a schematic top view of a heat transfer element according to Figure 3; [0026] Figure 8 is a schematic top view of a heat transfer element according to the invention; [0027] Figure 9 is a schematic cross-sectional view of a detail of a heat transfer element according to the invention; [0028] Figure 10 is a schematic side view of a joint between two heat transfer elements; [0029] Figure 11 is a schematic view of a heat transfer element, cut open and seen from the longitudinal direction; and [0030] Figure 12 is a schematic top view of a heat transfer element.

[0031] For the sake of clarity, the invention is shown simplified in the figures. Similar parts are denoted with the same reference numerals.

DETAILED DESCRIPTION OF THE FIGURES [0032] The heat transfer element shown in Figure 1 comprises three heat transfer elements 1a to 1c connected in series, which together with a heating/cooling unit 2, connecting pipes 3 and a pump 4 form a closed a loop.

In the loop, the same fluid medium flow circulates through each heat transfer element 1a to 1c. Typically, the fluid medium is water, into which required additives, such as anti-corrosives, have been mixed, but also other suitable mediums can naturally be used. In the heating/cooling unit 2 located before the first heat transfer element 1 a, the temperature of the fluid medium is adjusted as desired, after which it starts its circulation through the heat transfer elements 1a to 1c. The fluid channels of the heat transfer elements 1a to 1c are connected to each other with connecting pipes 3, or alternatively, the heat transfer elements 1 a to 1 c are arranged successively on each other's extension. The fluid medium is circulated in the heat transfer device by means of one or more pipes 4. Further, there is a blower 5a to 5c connected to each heat transfer element 1 a to 1 c, the air flows generated with the blowers being supplied to longitudinal air channels in the heat transfer elements 1a to 1c.

Thus, a pressure higher than the atmospheric pressure prevails in the air channels. Flow openings have been formed in the heat transfer elements 1 a to 1 c, through which openings an air flow A heated or cooled by the fluid medium can discharge. In the element 1a of Figure 1, the flow opening is a discharge opening in the longitudinal direction of the element, whereby the discharging air flow A is a broad jet. In the element 1b, several substantially point-like openings have been formed, whereby the air flows A discharging out of the element 1b have a beam-like shape. The flow opening of the element 1c is adjusted to be closed, whereby no air flow is discharged out of it, but the element 1 c heats the environment only by heat radiation.

[0033] Further, the system can be arranged in such a way that the fluid medium circulates in a closed cycle through a channel 45. Thus, the control unit 30 controls a valve 46, which lets, according to the need, some fluid medium from the heating/cooling unit to the fluid circulation.

[0034] Figure 2 shows an alternative solution, in which the heat transfer element 1 comprises two fluid channels, whereby the flow supplied from the pump 4 flows in one direction in one channel and returns in the opposite flowing direction along another channel back to the pump 4. At the far end of the heat transfer element 1, the first and the second fluid channel are

combined with a connecting pipe 3, for example. It is obvious that also in this case several heat transfer elements may be arranged successively. An air flow is supplied with two blowers 5a and 5b to the air channel of the heat transfer element shown in Figure 2. The blowers 5a and 5b are arranged at distances from the ends of the heat transfer element 1, because the intention is to distribute the air flow as evenly as possible over the whole length of the heat transfer element 1. The number and efficiency of blowers 5 are naturally determined as required in each case. In some cases, the required blowing can be achieved by using only one efficient blower 5d, from which the air flow is conducted along supply channels 6a and 6b to a desired point in the heat transfer element 1, as indicated by broken lines in Figure 2. Correspondingly, an air flow can be conducted from the blower 5d along appropriate supply channels to several heat transfer elements. Such a centralized blower 5d can be positioned and also insulated efficiently, so that it does not cause significant noise in the passenger cabin of a vehicle, for instance.

[0035] The heat transfer element 1 of Figure 3 comprises a cover 7, which is substantially airtight, except for a flow opening 8 in the upper part of the element 1. Thus, part of the air flow supplied to an air channel 9 in the heat transfer element 1 can discharge out of the element 1 through the flow opening 8. Further, the element 1 comprises a longitudinal fluid channel 10, along which the fluid medium flow is conducted. The cover 7 of the heat element 1 functions as a heat-radiating surface, so that the heat output transferred from the element 1 by radiation can be controlled by changing the dimensioning, colouring and surface quality of the cover 7. The element 1 is preferably shaped in such a way that it narrows towards the upper end. In addition, the upper part of the element 1 is provided with fins, which are heated by the effect of the heat conducted from the fluid channel 10. Fins 11 are arranged on both sides of the inner surface of the cover 7. Heat is conducted along the cover 7 also to the fins 11 opposite to the fluid channel 10. Further, the fins 11 are arranged in such a way that before the flow opening 8 they form a narrow labyrinth-like structure, through which the air flowing from the air channel 9 to the flow opening 8 must travel in such a way that its direction of flow varies.

The flow velocity of the air flowing in the labyrinth-like structure increases due to the narrow openings. The increase in the flow velocity makes the heat transfer from the fins to the air flow more efficient. Further, when the flow discharging out of the flow opening 8 has a high velocity, the effect of the

outgoing air flow extends farther away from the flow opening 8, which is advantageous for instance in removing vapour from vehicle windows. Further, the amount of discharging air can be maintained relatively small, whereby it is comfortable to the passengers. The size B of the flow opening 8 is selected in such a way that the desired air flow is achieved. The width of the discharge opening can be about 0.5 mm. It is naturally clear that the element 1 may comprise several flow openings 8, which may further be directed in different directions.

[0036] The heat transfer element 1 of Figure 3 is preferably made of metal, such as an aluminium alloy, by extruding. Thus, an elongated piece having a desired cross-sectional profile can be extruded in advance, and portions of required sizes can be cut out of such a profile as late as upon the assembly of the heat transfer device.

[0037] Figure 4 shows a second structural alternative for the heat transfer element 1. In this case, the element 1 contains two parts, i. e. the first half 1 a and the second half 1 b, which are manufactured separately by extruding, for instance. As regards the manufacturing technique, manufacturing such halves may be easier than manufacturing a continuous structure shown in Figure 3. In addition, simpler tools can be used in extrusion.

The first half 1a comprises in the lower part of the cover 7 a wedge-shaped opening 12, into which the wedge-shaped connecting surface 13 in the lower part of the second half 1b can be tightly inserted when the element 1 is assembled. The connection can further be secured by welding, soldering, an adhesive or another appropriate manner. The connection can also be a crimp connection or a shape-locked connection. Further, the upper ends of the halves 1a and 1b can be connected to each other at given distances, for instance with screws. There is preferably a good contact surface between the halves 1a and 1b to allow efficient conduction and even distribution of heat between the halves. The element 1 assembled of the halves 1a and 1b is substantially according to the continuous element shown in Figure 3. The element 1 is mounted on a wall or the like mounting surface in the room to be heated, such as a vehicle cabin, by means of a mounting part 22 integrated in the outer surface of the second half 1 b, for example, whereby the second half 1 b is on the side of the mounting surface and the first half 1a forms the visible surface of the element 1.

[0038] Figure 5 shows a half 1 c, which can be connected to the half 1b instead of the half 1 a shown in Figure 4. Such a module structure allows versatile modification of the element 1. The half 1c comprises a second fluid channel 15, along which the return flow of the fluid medium can be conducted.

The fluid medium in the second fluid channel 15 makes heat radiation transfer from the half 1 c more efficient. Further, the outer surface of the half 1 c may be provided with protrusions 16, owing to which scattering of the heat radiation to the environment is made more efficient.

[0039] Figure 6 shows still another option for manufacturing the heat transfer element 1 according to the invention. The element 1 is extruded in an open form, whereby sides 17a and 17b of the element are at the upper end at a distance from each other. The sides 17a and 17b are connected to each other at the lower end of the element 1 with a hinge member 18. The hinge member 18 can, at its simplest, be a thinned portion, which allows the sides 17a and 17b to be bent against each other around the hinge member 18.

Such a construction facilitates manufacturing.

[0040] Figure 7 is a top view of a part of an element 1 according to the invention. As can be seen, the flow opening 8 is in this case an elongated opening in the longitudinal direction of the element 1, whereby the air flow generated by it is a relatively thin but broad air curtain. A similar effect is achieved by using several successive and parallel elongated flow openings.

[0041] Figure 8 is a top view of a part of an element 1 according to the invention. In this case, there are several flow openings 8 located at distances from each other. The air flow discharging from point-like flow openings 8 forms a beam-like jet. The properties of the element 1 can be arranged as desired by affecting the number and size of the flow openings 8.

[0042] Figure 9 shows a part of the upper end of a heat transfer element 1 according to the invention. The element comprises a control member 19, such as an adjusting screw, with which the size B of the flow opening can be adjusted. Thus, the adjusting screw is arranged to bend the right cover plate 20 relative to the left cover plate 21. When required, the flow opening 8 can be adjusted with a control member 19 to be completely closed at desired points. Further, the adjustment of the flow opening 8 can in some cases be performed by bending the cover plates 20 and 21 in such a way relative to each other that they remain permanently in the desired position. It is also possible to arrange the adjustment of the flow opening to be performed

with an actuator controlled by a control unit 30 of the heat transfer device.

Such a control unit 30 can control in a centralized manner the size of the flow openings, the blowing efficiency and the temperature of the fluid flow in all elements of the heat transfer device.

[0043] Figure 10 shows one way to connect heat transfer elements according to the invention to each other. Thus, a seal 23, for instance a sealing strip, is arranged between the first element 1a and the second element 1b.

Further, the fluid channels 10 of the elements 1a and 1b are connected to each other by means of an adapter tube 24 sealed against the inner surface of the fluid channels.

[0044] The heat transfer element shown in Figure 11 does not comprise a labyrinth-like structure, but a large number of openings 40 having small diameters have been formed in the cover 7, the air flow being conducted through them from the air channel 9 to the flow openings 8 on the outer surface of the cover 7. In the narrow openings 40, the flow velocity increases, whereby heat transfer from the cover 7 heated or cooled by the fluid channel 10 is made more efficient. Further, the length of the openings 40 is determined in such a way that the required heat transfer is achieved. The diameter of the openings 40 is typically less than 1 mm, preferably 0.5 mm. It is relatively easy and inexpensive to make such openings with a beam machining method, such as a laser, for instance, after manufacturing a preform. In such a case, it is very simple to manufacture the preform by extruding, for example. Adjacent openings 40 do not have to be parallel, but the openings 40 can be directed in a desired manner.

[0045] Figure 12 shows that the position of the openings 40 can be arranged in such a way that they form a desired blow pattern. The openings 40 can be arranged in a line-like manner 41, in which case the formed blow pattern is curtain-like, or alternatively, openings 40 can be arranged in limited areas 42, in which case the formed blow pattern is point-like. On the other hand, a very narrow longitudinal opening 43 may be machined in the cover 7 with a laser, which opening forms a curtain-like blow pattern.

[0046] The drawings and the related specification are only intended to illustrate the idea of the invention. The details of the invention can vary within the scope of the claims.