CA2244064C - Regenerative heat recovery unit comprising heat accumulators tiltably movable to have a valve function - Google Patents
Regenerative heat recovery unit comprising heat accumulators tiltably movable to have a valve function Download PDFInfo
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- CA2244064C CA2244064C CA 2244064 CA2244064A CA2244064C CA 2244064 C CA2244064 C CA 2244064C CA 2244064 CA2244064 CA 2244064 CA 2244064 A CA2244064 A CA 2244064A CA 2244064 C CA2244064 C CA 2244064C
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- heat recovery
- recovery unit
- heat accumulator
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- Y02B30/16—
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- Y02B30/563—
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Abstract
The invention relates to a heat recovery unit comprising a casing (1), which encloses at least one regenerative heat accumulator (5), whereby the casing (1) has a supply air opening (10), an exhaust air opening (15), an exterior air opening (20) and a used-air opening (25), and whereby exhaust air and supply sir alternately pass through the heat accumulator (5). The heat accumulator (5) has, by means of a rotational movement, a valve funciton which opens respectively closes said openings (10-25) when the heat accumulator (5) rotates from a first position for exhaust air throughflow to a second position for exterior air throughflow.
Description
WO 97l284I2 I PCT/SE97/00153 Regenerative heat recovery unit comprising heat accumulators tiltably movable to have a valve function The present invention relates to a heat recovery unit, particularly a heat recovery unit having movable heat accumulators.
Heat recovery units are used in. amongst others, ventilation systems for e.g.
venti-lating buildings and at the same time returning the heat out of the extlaust air which is ventilated out from the building to the e:cterior air which is fed into the building in the form of inlet air.
A heat recovery assembly which is present on the market has iZVO plate housings which each surround their own regenerative plate package which fonts the heat accumulators. Each plate housing is mutually joined with two valve housings.
Each valve housing comprises a valve leaf which are each influenced by their own valve 1 ~ motor. One of the valve housings is equipped with a supply air fan which is connec-ted to a supply air channel on the valve housing. and with an e.~chaust air fan which is connected to an e,~chaust channel on the valve housing. the valve housing itself is connected to each and all of the plate housings via a supply air opening and respectively an exhaust air opening on the respective plate housings. The second valve housing is equipped with a used-air channel and an exterior air channel and is connected ?0 to each of the plate housings via a used-air opening and respectively an exterior air opening of the respective plate housings.
Exhaust air and respectively exterior air passes alternately through the plate packages.
When one of the plate packages has warmed up and the other has cooled, the valve leaves in the valve housings are switched over, whereby the exhaust and respectively exterior air change plate package and have the opposite direction of flow compared with the air which previousiv flowed in the respective plate packages.
Heat recovery units are used in. amongst others, ventilation systems for e.g.
venti-lating buildings and at the same time returning the heat out of the extlaust air which is ventilated out from the building to the e:cterior air which is fed into the building in the form of inlet air.
A heat recovery assembly which is present on the market has iZVO plate housings which each surround their own regenerative plate package which fonts the heat accumulators. Each plate housing is mutually joined with two valve housings.
Each valve housing comprises a valve leaf which are each influenced by their own valve 1 ~ motor. One of the valve housings is equipped with a supply air fan which is connec-ted to a supply air channel on the valve housing. and with an e.~chaust air fan which is connected to an e,~chaust channel on the valve housing. the valve housing itself is connected to each and all of the plate housings via a supply air opening and respectively an exhaust air opening on the respective plate housings. The second valve housing is equipped with a used-air channel and an exterior air channel and is connected ?0 to each of the plate housings via a used-air opening and respectively an exterior air opening of the respective plate housings.
Exhaust air and respectively exterior air passes alternately through the plate packages.
When one of the plate packages has warmed up and the other has cooled, the valve leaves in the valve housings are switched over, whereby the exhaust and respectively exterior air change plate package and have the opposite direction of flow compared with the air which previousiv flowed in the respective plate packages.
Another exisnne heat recovery assembly is the rotation heat exchan~er where a continuous airflow flows through a rotating cylinder. The axis of rotation of the cylinder extends into a plane which coincides with a wall. On one side of the wall, warm air flows and on the other side cold air flows_ By letting the warm air pass through the cylinder, the part of the cylinder which is on the ''waxen" side is warmed up. When the cylinder rotates, the warmed up pan of the cylinder will go over to the ''cold" side. whereby the cold air which flows throu4h the cylinder is warmed up.
A problem with conventional heat recovery units is the need for a cross-over valve. In addition, the arrangement of elements in conventional heat-recovery units can create undesirable noise when the ventilation system switches over from exterior air to exhaust air or vice-versa.
It is an object of the present invention to obviate or mitigate the problems associated with conventional heat recovery units.
The present invention relates to a heat recovery unit comprising a casing which contains at Ieast one regenerative heat accumulator, whereby the casing has an inlet air opening, an exhaust air opening, an exterior air opening and a used-air opening, and whereby the exhaust air and the exterior air alternately pass through the heat accumulator.
A main object of the present invention is to achieve a heat recovery unit which is-cquipped wirii at least one regenerative heat accumulator. which eliminates the need of a separate cross-over valve, which controls the e.~chaust air and the e:~terior air which pass through the heat accumulators. Preferably two heat accumulators are coupled together to a heat recovery unit.
Anotr'~er object of the present invention is to provide a heat recovery unit which has a very low sound change in the ventilation system when the switching over occurs from the exterior air to the exhaust air, and vice versa, in the heat accumulators.
2a A further object of the present invention is to provide possibility of recirculatory operation with the heat recovery unit. which recirculates the exhaust,air through the supply air opening under special operating conditions.
A further object of the present invention is to provide that the air flows in the same to direction through the openings in the casino, irrespective of the direction of the air through the heat accumulators.
A further object of the present invention is to provide a low pressure drop across the heat recovery unit.
A further object of the present invention is to provide a high degree of temperature exchange in the heat recovery unit.
A further object of the present invention is to provide a heat recovery unit which permits simple cleaning.
According to the invention these objects are achieved by a heat recovery unit in which the heat accumulator, by means of a rotating movement, has a valve function which opens and respectively closes said openings when the heat accumulator moves from a first position for exhaust air throughflow to a second position for exterior air throughflow.
According to an aspect of the present invention there is provided a heat recovery unit, comprising a casing, a pair of exhaust airflow openings provided in the casing, a pair of supply airflow openings provided in the casing, a regenerative heat accumulator having two parallel end faces, the regenerative heat accumulator being housed by the casing, and the regenerative heat accumulator rotatable about an axis of rotation perpendicular to a normal direction of the end 2o faces from a first position in which the end faces cover the pair of exhaust airflow openings and leave open the pair of supply airflow openings to a second position in which the end faces cover the pair of supply airflow openings and leave open the pair of exhaust airflow openings.
According to a preferred embodiment the pair of supply airflow openings comprises a supply air opening and an exterior air opening.
According to another aspect of the present invention there is provided a heat recovery assembly comprising two regenerative heat recovery units as discussed in the previous paragraph, the regenerative heat recovery units being coupled together so that the openings of the respective heat 3o recovery unit are joined to each other and wherein rotational movements of the regenerative heat accumulators are controlled so that when the regenerative heat accumulator in one of the heat recover units is in the first position, the regenerative heat accumulator in the other heat recovery unit is in the second position and vice versa.
Wo 97r18412 4 PCT/SE97l00153 The invention will be described in more detail below by means of examples of embodiments with reference to the appended drawings.
Figure 1 shows a perspective view of a heat recovery unit according to a first embodiment.
Figure 2 shows a view from above of two heat recovery units which are coupled together to form a heat recovery assembly.
Figure 3 shows a perspective view of a heat recovery unit according to a second embodiment.
Figure ~ shows a side view of a heat recovery unit according to the second embodiment.
Figure ~ shows an example of the application of a heat recovery unit according to the second embodiment.
Figure 6 shows a side view of a heat recovery unit according to the second embodiment in a third position.
Figures 7-8 show side views of a heat recovery unit according to a third embodiment in two different positions.
Figure 1 shows a perspective view of a heat recovery unit according to a first embodiment. The heat recovery unit comprises a casino 1 which forms a space 2, which contains a regenerative heat accumulator ~. according to this embodiment the casing I is elongated with a length which is Greater than its width and height.
The heat accumulator ~ which is placed inside the casino 1 has a length and a width which are somewhat less than the length and width of the space 2 which is formed by the casing I so that a clearance is formed betvueen the inner surface of the casing 1 and the heat accumulator ~. The thickness of the heat accumulator ~ is less than the height of the space 2. This allows the heat accumulator ~ to rotate forwards and backwards inside the casing I . The swinGing movement takes place as a tipping movement around a shaft 34 which carries the heat accumulator ~. The shaft 30 passes through a hole in the casing 1 and is mounted in bearings in the casing 1 on both sides of the heat accumulator ~. In Fiwre 1 the shaft 30 is imagined to be horizontal.
The casing i has ends at which a supple air opening 10, an exhaust air opening 1 ~, - an e:ctenor air opening 20 and a used-air opening ~~ are arranged. which each cooperate with end faces 3~ of the heat accumulator 5. The end faces 35 are prefer-ably parallel with the shaft 30 and planar and lie against the inside of the inner surfaces of the casing 1 around the openings 10-?~. The supply air opening 10 ~d ~e used-air opening 25 and respectively the exhaust air opening 15 and the exterior air opening 20 are separated by means of a wall part 27 and respectively 28, which can be formed by part of the casing l . In the embodiment shown, both of the end faces 35 have sealing strips 36 along their upper and lower edges. In a first position, shown in Figure l, the upper strip 36 of the iefthand end face 3~ seals against the upper side of the casino i . and the lower strip against the lower edge of the wall pan ?
8. at the same time as the upper strip ~6 of the riQhthand end face 3~ seals against the upper edge of the wall pan ?7 and its lower strip seals against the inside of the bottom of the casing i .
The heat accumulator can be built up from a number of plates 37 (Figure 4) which form a plurality of throughflow channels 38 for air. The throughflow channels 38 are preferably directed in the direction of the thickness of the heat accumulator S. The plates 37 consequently form a large heat-absorbing and respectively heat-emitting surface.
The heat recovery unit can be used in a ventilation system for ventilating a building, e.g. an appartment house or an office building. The air which leaves rooms in the building by the ventilation is called e:chaust air and the air which is supplied to the i ~ rooms is called supply air.
By means of its forwards and backwards rotating movement the heat accumulator has a valve function which opens and respectively closes said openings 10-25 when the heat accumulator 5 rotates from a first position for exhaust air throughflow to a second position for supply air throughflow.
?0 With e,Yhaust air throuahflow. when the heat accumulator ~ is positioned in the first position, e:chaust air at room temperature flows in through the e~chaust air opening 1 ~ and into the space ? in which the heat accumulator ~ is positioned. The exhaust ?5 air room temperature flows subsequently through the heat accumulator ~ in a direc-lion which substantially corresponds to the direction of its thickness. The heat accu-mulator ~ is thereby heated up by the throuohflowin~ exhaust air. The exhaust air then flows out through the used-air opening 2~ in the form of used air and subse-quently leaves the space ? in which the heat accumulator p is placed. The used air which leaves the used-air opening ?5 can subsequently suitabtv flow into a channel ~2 (Figure ~). which transports the used air out of the building.
A first sensor >j senses the temperature of the used air which leaves the used-air openin~ 2~. A reference sensor ~6 can. for e;cample, be placed in the building which is to be ventilated. whereby the reference temperature will correspond to the room - temperature in the buildin~. The first sensor » and the reference sensor ~6 are connected to a control unit 60. When the difference between the temperature which the first sensor » senses and the temperature which the second sensor ~6 senses decreases to a predetermined value, the control unit 60 gives a sisal to a stepping motor 6?. which is connected to the shaft 30. whereby the motor 63 rotates the heat accumulator p to the second position for supply air throughflow_ Instead of a step-ping motor it is conceivable to use another power generating means such as a hydraulic or pneumatic cylinder.
During exterior air throuehflow, exterior air flows in through the exterior air opening ?0 and into the space 2 in which the heat accumulator ~ is positioned.
The exterior air then flows throush the heat accumulator p in a direction which substantially corresponds to the direction of its thickness. T'he exterior air is thereby heated up by the heat accumulator ~ warmed, up by the e.~chaust air. 'ihe air then flows out through the supply air openin' I O in the form of supply air and conse-quently leaves the space 2 in which the heat accumulator ~ is positioned. The supply air which leaves the supply air opening 10 then flows either directly into the build-ing or into a duct system (not shown) which distributes the air into the different 2~ rooms of the building.
A second sensor ~7. which is placed by the supply air opening 10 and connected to the control unit 60 senses the temperature of the warmed up supply air.
When the difference between the temperature which the second sensor ~ r senses and the WO 97/28412 7 PCT/SE9'7100~53 temperature which the reference sensor ~6 senses increases to a predetermined value, the control unit 60 gives a signal to the stepping motor 62. whereby the motor 62 tips the heat accumulator ~ to the first position for exhaust air throuQhflow.
A fan part 6~ which comprises two fans 66.67 (Figure 4) can be connected to the supply air opening 10 and the used-air opening 2~. and a filter pan 70 which comprises twa filters 71,7? can be connected to the e.~chaust air opening 1 ~
and the exterior air opening 10.
When the heat accumulator ~ is heated up by the exhaust air throu~hflow, the e~chaust air at room temperature will first meet one side, in Figure 4 the lower side, of the heat accumulator ~. This first side of the heat accumulator ~ will have a higher temperature than the second side. if the heat accumulator ~ is rotated to the second position before the second side of the heat accumulator ~ has been able to 1 ~ achieve the same temperature as the first side.
According to the first embodiment in Figure 1. the e.Yhaust air and the supply air flow in opposite directions through the heat accumulator ~. This means that the exterior air fast will meet the side of the heat accumulator ~ which has the lowest temperature. The exterior air will consequently be successively warmed up along its flow path through the heat accumulator ~, which increases ttie total efficiency of the heat recovery unit_ Figure ? shows a view from above of two heat recovery units according to Figure 1, 2~ which are connected to form a heat recovery assembly. The e:cterior air openings 20 on each unit are coupled together by a tube 31. the exhaust air openings 15 are coupled together by a tube 31 (not shown). the used-air openings ?~ are coupled together by a tube 32 and the supply air openings 10 are coupled together by a tube 3? (not shown). The tube 31. which is connected. to the exterior air openings ?0.
wo 97J28412 ~ PCTISE97l00153 discharges into an e.~cterior air channel 33 in which a filter 7I is arranged_ The tube 31, which is connected to the exhaust air openings 1 ~ discharges in an exhaust air channel 33. in which a filter 72 is arranged (not shown). The tube 32 which is connected to the used-air openings 26 discharges into a common used-air channel 34, in which a fan 66 is arranged. The tube 32 which is connected to the supply air openings 10 discharges into a common supply air channel 3~. in which a fan 67 is arranged (not shown).
The rotational movement of the heat accumulators ~ are so controlled that when the heat accumulator ~ of one of the heat recovery units is in the first position for exhaust air throughflow, the heat accumulator ~ of the second heat recovery unit is in the second position for exterior air throuahflow, and vice versa.
In this way the ventilation in for example a building can be increased compared with I ~ only one heat recovery unit, whereby a nearly continuous ventilation of the building is achieved. Each ofthe heat recovery units can be equipped with its own stepping motor 62 which brings about the rotationary movement of the respective heat accu-mulator 5. In this case the motors 62 should be synchronized so that when one of the heat accumulators ~ is in the first position. the second heat accumulator ~
should be in the second position. This synchronization can be performed with a control means 7~. Alternately, the heat recovery assembly can be equipped with only one motor, whereby the rotational movement of the motor is transferred to each of the shafts 30 on the heat accumulators a by a gear or a link mechanism (not shown).
Each of the heat recovery units can be equipped with sensors W -~7 which sense the temperature as described above in cormection with Figure I. However, it is also appropriate that common sensors ~~-~7 and a single control unit 60 are arranged for both of the heat recovery units in order to give control signals to the electric motors 62 or the electric motor. The control unit 60 can be connected to the control means W~ 97/28412 9 PCTlSE97I00153 It is also possible to couple together more than nvo heat recovery units to make a larger heat recovery assembly.
Figure 3 shows a perspective view of a heat recovery unit according to a second embodiment. The casing 1 contains in this second embodiment two heat accumu-lators ~,~', which are placed side by side in each of their own chambers 40,45. The chambers 40,4 are separated from each other by means of a wall ~0. The casing has a supply air opening 10. an exhaust air opening 1~, an exterior air opening 20 and a used-air opening 2~, which each cooperate with the end faces 3~ of the heat accumulator ~ and ~'. respectively. Each of the openings 10-2~ is connected to both chambers 40.4, which means that each opening 10-2~ extends from the first chamber 40 to the second chamber 4~. The supply air opening 10 and the used-air opening 25 and respectively the exhaust air opening 1 S and the exterior air opening 20 are separated by means of the wall part 27 respectively 28, which can be formed as part 1 ~ of the casing 1.
A fan part 6~ which comprises two fans 66,67 (Figure 4) can be connected to the supply air opening 10 and the used-air opening 2~. and a filter part 70 which comprises two filters 71.72 (Figure ~) can be connected to the exhaust air opening 15 and the exterior air opening 20.
Precisely as in the heat recovery assembly according to Figure ?. the rotational movements of the heat accumulators ~,~' are so controlled that when the first heat accumulator ~ is in the first position for e.~chaust air throuQhflow, the second heat accumulator ~' is in the second position for exterior air throughflow, and vice versa.
Consequently, the ventilation in, for e.~campIe. a building can be increased whereby a near enough continuous ventilation of the building is achieved. Each of the heat accumulators ~.~' can, as in Figure 2. be equipped with its own stepping motor WO 97!18412 10 PCTISE9?/OOI53 62.62'. which brins about the rotational movement of each heat accumulator ~.~'.
The motors 6'_'.6?' shall in this case be synchronized so that when the first heat accumulator ~ i~ in the first position, the second heat accumulator ~' shall be in the second position and vice versa This synchronization can take place by a control unit 60. Alternatively, the heat recovery unit can be equipped with only one motor, where the rotational movement of the motor is transmitted to each of the shafts of the heat accumulators by a gear or a link mechanism (not shown).
During exhaust air throuehflow when the first heat accumulator ~ is set in the first position. air at room temperature in the form of e.~chaust air flows in through the exhaust air opening 1~ and into the first chamber 40, in which the first heat accu-mulator ~ is positioned. The exhaust air flows subsequently through the heat accu-mulator 5 in a direction which substantially corresponds to the direction of its thick-ness. the heat accumulator ~ is thereby heated up by the throuQhflowing exhaust air. The air then flows out through the used-air opening ?~ in the form of used air och consequenti~- leaves the first chamber =10. The used air which leaves the used-air opening 25 can then suitably flow into a channel 82 (Figure ~), which transports the air out of the building.
At the same time as e.~chaust air throughflow takes place in the first chamber 40.
exterior air throu~hflow takes place in the second chamber 4~, in which the second heat accumulator ~' is set in the second position far exterior air throuQhflow. Durine exterior air throuQhflow exterior air flows in through the exterior air opening 20 and into the second chamber ~~. The exterior air then flows through the second heat 2~ accumulator ~~ in a direction which essentially coincides with the direction of its thickness. The e~cterior air is thereby heated up by the second heat accumulator ~' which earlier has been warmed up by exhaust air during exhaust air throuahflow.
The air then flows out through the supply air opening 10 in the form of supply air and consequently leaves the second chamber ~1~. The supply air which leaves the supply air opening 10 then flows either directly into the building or into a tube system which distributes the air to the different rooms in the building (not shown).
According to this embodiment according to Figure 3, a control means for control-Tina the heat recovery unit can be constructed so that a first sensor >j senses the temperature of the exterior air which is flowing into the exterior air opening 20.
This first sensor 5~ is connected to a control unit 60, and is compensated.
which means that it gives signals to the control unit 60 which signals are the basis for how the heat recovery unit is to be regulated at different exterior temperatures.
A second i0 sensor ~7 whi~h i.s placed by the supply air opening 10 and connected to the control unit 60 senses the temperature of the warmed up supply air which leaves the supply air openings 10 ~f the respective chamber ~0,4~. This second sensor ~7 is regulated.
which means that it gives sisals to the control unit 60 which signals are a basis for how the heat recovery unit should be reeulated with respect to a suitably installed 1 ~ desired value which is programmed into the control unit. Vtrhen the supply air temperature is below the desired value of the second sensor ~7, the control unit 60 gives a sisal to the respective stepping motor 62,62', which are connected to the respective shafr 30,30' of the heat accumulators ~.~', whereby the first motor rotates the first heat accumulator ~ to the second position for exterior air throuah-20 flow. At the same time the second stepping motor 62' rotates the second heat accumulator ~' to the first position for exhaust air throughflow.
As an alternative the f rst sensor 5~ senses the temperature of the used air which leaves the used-air openings 2~ of the respective chamber 40.4. A reference sensor can. for example, be placed in the building which is to be ventilated, in order to sense the room temperature in the building. The first sensorp3 and the reference sensor are connected to the control unit 60. The second sensor p7 is placed by the supply air openings 10 of the respective chamber X0,45 and is connected to the control unit 60. whereby the second sensor ~7 senses the temperature of the warmed W('? 97/28412 I 2 PCT/SE97/00153 up supply air. When the difference between the temperatures sensed by the first and second sensors 55 and respectively 57 and the temperature sensed by the reference sensor 56 reaches a predetermined value, the control unit 60 gives a signal to the first and second stepping motors 62.62'. whereby the first motor 62 rotates the first heat accumulator ~ to the second position for exterior air throughflow. At the same time the second stepping motor 62' rotates the second heat accumulator ~' to the first position for exhaust air throughflow.
Figure ~ shows a lateral view of a heat recovew unit according to the second I O embodiment. The first heat accumulator ~ is shown with a plurality of parallel lines which extend in the direction of thickness of the first heat accumulator ~.
The parallel lines symbolize that the first heat accumulator ~ is built up by a plurality of plates 37. The solid arrows show exhaust air flows through the heat recovery assembly. The first heat accumulator 6 is set in the first position for the exhaust air 16 throuQhflow, wherein exhaust air flows through the exhaust air opening I S
into the first chamber X10, through the first heat accumulator ~ and out through the used-air opening ?5 in the form of used air.
The second heat accumulator ~' is hidden behind the wall SO which separates the 20 first and second chambers X0,45. thus the contours of the second heat accumulator are only shown with dashed lines. The second heat accumulator 5' is set in the second position for exterior air throughflow which is shown with dashed arrows.
A fan part 66 which comprises two fans 66_67 is connected to the supply air opening 25 10 and the used-air opening 35, and a filter part 70 which comprises two filters 71.
72 is connected to the exhaust air opening 1 ~ and the exterior air opening 20.
Figure ~ shows an example of the application of a heat recovery unit according to the second embodiment. The heat recovery unit can_ for example. be placed in an WO 97!28412 1 ~ PGT/5E9?!00153 isolated place in a building 79. However. it is also possible to place the heat reco-ven~ unit outside the building 79. Exhaust air F in the form of the interior air of the building 79 is led through an exhaust air channel 80 into the filter part 70 of the heat recoven~ unit and further in through the e,Yhaust air opening 15 to one of the two s chambers 40 alt. 4~; which each contain a heat accumulator ~,~'. The exhaust air passes through one of the heat accumulators 5,5' and out through the used-air opening 2~ in the form of used air A which is led through a used-air channel 82 in order to be let out outside the building 79. At the same time. exterior air U
is led through an exterior air channel 84 into the filter part 70 of the heat recovery unit and further in through the exterior air opening ?0 to the second one of the two chambers 40 alt. 4~. The e:cterior air passes through the second of the two heat accumulators ~
,5' and out through the supply air opening 10 in the form of supply air T, which is led through a supply air channel 86 in order to be let into the building 79.
1~ Figure 6 shows a heat recovery unit according to Figure 4 where both the first and the second heat accumulators ~,~' are in a third position, in which position neither of the openings 10-2S in the casino 1 of the heat recovery unit are closed by means of the end faces 3 ~ of the heat accumulators ~.~'. On the other hand both the exterior openings 20 and the used-air openings 2~ are closed by means of valve leaves 90 which prevent exterior air to flaw from the exterior air opening 20 and the exhaust air opening 25 to the supply air opening 10. In the third position, exhaust air can flow from the exhaust air opening 1S to the supply air opening without passing through the heat accumulators S,S', whereby an internal air circu-lotion in, for example, a building can be achieved. The third position can be taken ?S during, for example. a power cut or during night or weekend stoppages. when the stepping motors which bring about the rotational movement of the heat accumula-tors ~.~' can be so designed that they automatically rotate the heat accumulators S.S' to the third position during shutdowns.
Fieure 7 shows a lateral view of a heat recovery unit according to a third embodi-ment. The first heat accumulator ~ here is tipped into the second position for exterior air throughflow. At the same time the second heat accumulator ~' is tipped into the first position for exhaust air throughflow. Each of the heat accumulators ~.~' is partitioned with a dividing wall 9~. which e;ctends in the direction of thick-ness of the heat accumulators ~,~', whereby this dividing wall 9~ cooperates with valve leaves 96, which are synchronized with the rotational movement of the asso-ciated heat accumulator ~.~'. This synchronization can. for example. be achieved by means of a link system (not shown). The dividing wall 95 and the valve iPaves 96 can together cooperate in order to minimize the losses in the heat recovery when the heat accumulators ~,~' rotatate from the first to the second position. and vice versa. Another object of the dividing wall 95 and the valve leaves 96 will be explained in connection with Figure 8.
1 ~ Figure 8 shows a heat recovery unit according to Figure 7, where both the first and the second heat accumulators ~.~' are in a third position, in which position none of the openings I 0-25 in the casing I of the heat recovery unit are closed by means of the end faces 3~ of the heat accumulators ~.~'. By means of the dividing wall 95 and the valve leaves 96, however, two, from each other separated. substantially airtight ?0 spaces are formed on each side of the dividing wall 95 and the valve leaves 96.
Consequently. e.chaust air can flow through the e;chaust air opening 1 ~ and out throu~ll the supply air opening 10, whereby a recycle air function in the form of an intemaI air circulation is achieved in, for example, a building. As described in connection with Figure 6, the third position can be taken during, for example, 25 power failures.
In the summer months when the e;cterior air temperature is relatively high.
the accumulators ~,~' in the heat recovery unit can remain in either the first or the second position for a long time. A time function built into the control unit 60 can WO 97/28412 I 7 PCTISE9'7100153 then ''exercise' the rotational function at regular time intervals. for example one rotation or tipping per day. whereby the movable parts of the heat recovery unit are brought into motion in order to prevent them from sticking. -An advantage of the heat recovery unit according to the invention is that it can be applied at a long distance from an outer wall in a building, as the air the whole time flows in the same direction in the channels 80-86 which are connected to the heat recovery unit.
14 Another advantage of the heat recovery unit is that if the rotating shafr 30 of the heat accumulator ~.~' is placed horizontally, exhaust air will flow substantially upwards through the heat accumulator ~_~'. This means that water which condenses on the heat absorbing surfaces of the heat accumulator 5,~' will stay there and in the second position of the accumulator will be absorbed by the exterior air which flows 1 ~ through the heat accumulator 5.~'. Consequently, no thaw water piping for the heat recovery unit is required. The efficiency of the heat recovery unit is also increased in this way because latent heat. which from the beginning is contained in the water vapour, is recovered.
20 Yet another advantage of the heat recovery unit according to the invention is that the heat accumulator ~,~' is easy to clean because the throuahflow direction of the air through the heat accumulator 5,5' occurs substantially in the direction of its thickness which is considerably less than its length and width, so that the throughflow channels are short and easy to clean by e.g. by rinsing with water.
Yet another advantage of the heat recovery unit according to the present invention is that the sound change during the change from the exterior air throuahflow to the exhaust air throuehflow and vice versa is very low. According to the invention, air flows the whole time in the same direction through the openings 10-?~ in the casino I and in the channels 80-86 which are connected thereto. which means that the sound chance is low because no large air volume has to chance direction of flow.
Yet another advantage of the heat recovery unit according to the present invention is that the pressure drop over the heat accumulator ~.~' is low because the path of the air through the heat accumulator ~,~' is relatively short. 'This means that a Lower fan capacity is required in order to produce the flow of the air and it also means a lower sound level.
It has been described above how heat can be recovered by the heat recovery unit according to the invention. It is: however, possible by means of the heat recovery unit to shut out warm air from, for example, a building in which the indoor tempera-ture should be less than the outdoor temperature. The heat recovery unit will then 1 ~ work the other way round, whereby warm exterior air will give off its heat to the heat accumulator 5,5' which has been cooled by the .exhaust air throughflow.
The exterior air will thus be cooled down and flow into the rooms of the building in the. form of cool supply air.
The foregoing description of the preferred embodiments of the present invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application. Many modifications, variations and adaptations are possible without departing from the scope of the invention.
A problem with conventional heat recovery units is the need for a cross-over valve. In addition, the arrangement of elements in conventional heat-recovery units can create undesirable noise when the ventilation system switches over from exterior air to exhaust air or vice-versa.
It is an object of the present invention to obviate or mitigate the problems associated with conventional heat recovery units.
The present invention relates to a heat recovery unit comprising a casing which contains at Ieast one regenerative heat accumulator, whereby the casing has an inlet air opening, an exhaust air opening, an exterior air opening and a used-air opening, and whereby the exhaust air and the exterior air alternately pass through the heat accumulator.
A main object of the present invention is to achieve a heat recovery unit which is-cquipped wirii at least one regenerative heat accumulator. which eliminates the need of a separate cross-over valve, which controls the e.~chaust air and the e:~terior air which pass through the heat accumulators. Preferably two heat accumulators are coupled together to a heat recovery unit.
Anotr'~er object of the present invention is to provide a heat recovery unit which has a very low sound change in the ventilation system when the switching over occurs from the exterior air to the exhaust air, and vice versa, in the heat accumulators.
2a A further object of the present invention is to provide possibility of recirculatory operation with the heat recovery unit. which recirculates the exhaust,air through the supply air opening under special operating conditions.
A further object of the present invention is to provide that the air flows in the same to direction through the openings in the casino, irrespective of the direction of the air through the heat accumulators.
A further object of the present invention is to provide a low pressure drop across the heat recovery unit.
A further object of the present invention is to provide a high degree of temperature exchange in the heat recovery unit.
A further object of the present invention is to provide a heat recovery unit which permits simple cleaning.
According to the invention these objects are achieved by a heat recovery unit in which the heat accumulator, by means of a rotating movement, has a valve function which opens and respectively closes said openings when the heat accumulator moves from a first position for exhaust air throughflow to a second position for exterior air throughflow.
According to an aspect of the present invention there is provided a heat recovery unit, comprising a casing, a pair of exhaust airflow openings provided in the casing, a pair of supply airflow openings provided in the casing, a regenerative heat accumulator having two parallel end faces, the regenerative heat accumulator being housed by the casing, and the regenerative heat accumulator rotatable about an axis of rotation perpendicular to a normal direction of the end 2o faces from a first position in which the end faces cover the pair of exhaust airflow openings and leave open the pair of supply airflow openings to a second position in which the end faces cover the pair of supply airflow openings and leave open the pair of exhaust airflow openings.
According to a preferred embodiment the pair of supply airflow openings comprises a supply air opening and an exterior air opening.
According to another aspect of the present invention there is provided a heat recovery assembly comprising two regenerative heat recovery units as discussed in the previous paragraph, the regenerative heat recovery units being coupled together so that the openings of the respective heat 3o recovery unit are joined to each other and wherein rotational movements of the regenerative heat accumulators are controlled so that when the regenerative heat accumulator in one of the heat recover units is in the first position, the regenerative heat accumulator in the other heat recovery unit is in the second position and vice versa.
Wo 97r18412 4 PCT/SE97l00153 The invention will be described in more detail below by means of examples of embodiments with reference to the appended drawings.
Figure 1 shows a perspective view of a heat recovery unit according to a first embodiment.
Figure 2 shows a view from above of two heat recovery units which are coupled together to form a heat recovery assembly.
Figure 3 shows a perspective view of a heat recovery unit according to a second embodiment.
Figure ~ shows a side view of a heat recovery unit according to the second embodiment.
Figure ~ shows an example of the application of a heat recovery unit according to the second embodiment.
Figure 6 shows a side view of a heat recovery unit according to the second embodiment in a third position.
Figures 7-8 show side views of a heat recovery unit according to a third embodiment in two different positions.
Figure 1 shows a perspective view of a heat recovery unit according to a first embodiment. The heat recovery unit comprises a casino 1 which forms a space 2, which contains a regenerative heat accumulator ~. according to this embodiment the casing I is elongated with a length which is Greater than its width and height.
The heat accumulator ~ which is placed inside the casino 1 has a length and a width which are somewhat less than the length and width of the space 2 which is formed by the casing I so that a clearance is formed betvueen the inner surface of the casing 1 and the heat accumulator ~. The thickness of the heat accumulator ~ is less than the height of the space 2. This allows the heat accumulator ~ to rotate forwards and backwards inside the casing I . The swinGing movement takes place as a tipping movement around a shaft 34 which carries the heat accumulator ~. The shaft 30 passes through a hole in the casing 1 and is mounted in bearings in the casing 1 on both sides of the heat accumulator ~. In Fiwre 1 the shaft 30 is imagined to be horizontal.
The casing i has ends at which a supple air opening 10, an exhaust air opening 1 ~, - an e:ctenor air opening 20 and a used-air opening ~~ are arranged. which each cooperate with end faces 3~ of the heat accumulator 5. The end faces 35 are prefer-ably parallel with the shaft 30 and planar and lie against the inside of the inner surfaces of the casing 1 around the openings 10-?~. The supply air opening 10 ~d ~e used-air opening 25 and respectively the exhaust air opening 15 and the exterior air opening 20 are separated by means of a wall part 27 and respectively 28, which can be formed by part of the casing l . In the embodiment shown, both of the end faces 35 have sealing strips 36 along their upper and lower edges. In a first position, shown in Figure l, the upper strip 36 of the iefthand end face 3~ seals against the upper side of the casino i . and the lower strip against the lower edge of the wall pan ?
8. at the same time as the upper strip ~6 of the riQhthand end face 3~ seals against the upper edge of the wall pan ?7 and its lower strip seals against the inside of the bottom of the casing i .
The heat accumulator can be built up from a number of plates 37 (Figure 4) which form a plurality of throughflow channels 38 for air. The throughflow channels 38 are preferably directed in the direction of the thickness of the heat accumulator S. The plates 37 consequently form a large heat-absorbing and respectively heat-emitting surface.
The heat recovery unit can be used in a ventilation system for ventilating a building, e.g. an appartment house or an office building. The air which leaves rooms in the building by the ventilation is called e:chaust air and the air which is supplied to the i ~ rooms is called supply air.
By means of its forwards and backwards rotating movement the heat accumulator has a valve function which opens and respectively closes said openings 10-25 when the heat accumulator 5 rotates from a first position for exhaust air throughflow to a second position for supply air throughflow.
?0 With e,Yhaust air throuahflow. when the heat accumulator ~ is positioned in the first position, e:chaust air at room temperature flows in through the e~chaust air opening 1 ~ and into the space ? in which the heat accumulator ~ is positioned. The exhaust ?5 air room temperature flows subsequently through the heat accumulator ~ in a direc-lion which substantially corresponds to the direction of its thickness. The heat accu-mulator ~ is thereby heated up by the throuohflowin~ exhaust air. The exhaust air then flows out through the used-air opening 2~ in the form of used air and subse-quently leaves the space ? in which the heat accumulator p is placed. The used air which leaves the used-air opening ?5 can subsequently suitabtv flow into a channel ~2 (Figure ~). which transports the used air out of the building.
A first sensor >j senses the temperature of the used air which leaves the used-air openin~ 2~. A reference sensor ~6 can. for e;cample, be placed in the building which is to be ventilated. whereby the reference temperature will correspond to the room - temperature in the buildin~. The first sensor » and the reference sensor ~6 are connected to a control unit 60. When the difference between the temperature which the first sensor » senses and the temperature which the second sensor ~6 senses decreases to a predetermined value, the control unit 60 gives a sisal to a stepping motor 6?. which is connected to the shaft 30. whereby the motor 63 rotates the heat accumulator p to the second position for supply air throughflow_ Instead of a step-ping motor it is conceivable to use another power generating means such as a hydraulic or pneumatic cylinder.
During exterior air throuehflow, exterior air flows in through the exterior air opening ?0 and into the space 2 in which the heat accumulator ~ is positioned.
The exterior air then flows throush the heat accumulator p in a direction which substantially corresponds to the direction of its thickness. T'he exterior air is thereby heated up by the heat accumulator ~ warmed, up by the e.~chaust air. 'ihe air then flows out through the supply air openin' I O in the form of supply air and conse-quently leaves the space 2 in which the heat accumulator ~ is positioned. The supply air which leaves the supply air opening 10 then flows either directly into the build-ing or into a duct system (not shown) which distributes the air into the different 2~ rooms of the building.
A second sensor ~7. which is placed by the supply air opening 10 and connected to the control unit 60 senses the temperature of the warmed up supply air.
When the difference between the temperature which the second sensor ~ r senses and the WO 97/28412 7 PCT/SE9'7100~53 temperature which the reference sensor ~6 senses increases to a predetermined value, the control unit 60 gives a signal to the stepping motor 62. whereby the motor 62 tips the heat accumulator ~ to the first position for exhaust air throuQhflow.
A fan part 6~ which comprises two fans 66.67 (Figure 4) can be connected to the supply air opening 10 and the used-air opening 2~. and a filter pan 70 which comprises twa filters 71,7? can be connected to the e.~chaust air opening 1 ~
and the exterior air opening 10.
When the heat accumulator ~ is heated up by the exhaust air throu~hflow, the e~chaust air at room temperature will first meet one side, in Figure 4 the lower side, of the heat accumulator ~. This first side of the heat accumulator ~ will have a higher temperature than the second side. if the heat accumulator ~ is rotated to the second position before the second side of the heat accumulator ~ has been able to 1 ~ achieve the same temperature as the first side.
According to the first embodiment in Figure 1. the e.Yhaust air and the supply air flow in opposite directions through the heat accumulator ~. This means that the exterior air fast will meet the side of the heat accumulator ~ which has the lowest temperature. The exterior air will consequently be successively warmed up along its flow path through the heat accumulator ~, which increases ttie total efficiency of the heat recovery unit_ Figure ? shows a view from above of two heat recovery units according to Figure 1, 2~ which are connected to form a heat recovery assembly. The e:cterior air openings 20 on each unit are coupled together by a tube 31. the exhaust air openings 15 are coupled together by a tube 31 (not shown). the used-air openings ?~ are coupled together by a tube 32 and the supply air openings 10 are coupled together by a tube 3? (not shown). The tube 31. which is connected. to the exterior air openings ?0.
wo 97J28412 ~ PCTISE97l00153 discharges into an e.~cterior air channel 33 in which a filter 7I is arranged_ The tube 31, which is connected to the exhaust air openings 1 ~ discharges in an exhaust air channel 33. in which a filter 72 is arranged (not shown). The tube 32 which is connected to the used-air openings 26 discharges into a common used-air channel 34, in which a fan 66 is arranged. The tube 32 which is connected to the supply air openings 10 discharges into a common supply air channel 3~. in which a fan 67 is arranged (not shown).
The rotational movement of the heat accumulators ~ are so controlled that when the heat accumulator ~ of one of the heat recovery units is in the first position for exhaust air throughflow, the heat accumulator ~ of the second heat recovery unit is in the second position for exterior air throuahflow, and vice versa.
In this way the ventilation in for example a building can be increased compared with I ~ only one heat recovery unit, whereby a nearly continuous ventilation of the building is achieved. Each ofthe heat recovery units can be equipped with its own stepping motor 62 which brings about the rotationary movement of the respective heat accu-mulator 5. In this case the motors 62 should be synchronized so that when one of the heat accumulators ~ is in the first position. the second heat accumulator ~
should be in the second position. This synchronization can be performed with a control means 7~. Alternately, the heat recovery assembly can be equipped with only one motor, whereby the rotational movement of the motor is transferred to each of the shafts 30 on the heat accumulators a by a gear or a link mechanism (not shown).
Each of the heat recovery units can be equipped with sensors W -~7 which sense the temperature as described above in cormection with Figure I. However, it is also appropriate that common sensors ~~-~7 and a single control unit 60 are arranged for both of the heat recovery units in order to give control signals to the electric motors 62 or the electric motor. The control unit 60 can be connected to the control means W~ 97/28412 9 PCTlSE97I00153 It is also possible to couple together more than nvo heat recovery units to make a larger heat recovery assembly.
Figure 3 shows a perspective view of a heat recovery unit according to a second embodiment. The casing 1 contains in this second embodiment two heat accumu-lators ~,~', which are placed side by side in each of their own chambers 40,45. The chambers 40,4 are separated from each other by means of a wall ~0. The casing has a supply air opening 10. an exhaust air opening 1~, an exterior air opening 20 and a used-air opening 2~, which each cooperate with the end faces 3~ of the heat accumulator ~ and ~'. respectively. Each of the openings 10-2~ is connected to both chambers 40.4, which means that each opening 10-2~ extends from the first chamber 40 to the second chamber 4~. The supply air opening 10 and the used-air opening 25 and respectively the exhaust air opening 1 S and the exterior air opening 20 are separated by means of the wall part 27 respectively 28, which can be formed as part 1 ~ of the casing 1.
A fan part 6~ which comprises two fans 66,67 (Figure 4) can be connected to the supply air opening 10 and the used-air opening 2~. and a filter part 70 which comprises two filters 71.72 (Figure ~) can be connected to the exhaust air opening 15 and the exterior air opening 20.
Precisely as in the heat recovery assembly according to Figure ?. the rotational movements of the heat accumulators ~,~' are so controlled that when the first heat accumulator ~ is in the first position for e.~chaust air throuQhflow, the second heat accumulator ~' is in the second position for exterior air throughflow, and vice versa.
Consequently, the ventilation in, for e.~campIe. a building can be increased whereby a near enough continuous ventilation of the building is achieved. Each of the heat accumulators ~.~' can, as in Figure 2. be equipped with its own stepping motor WO 97!18412 10 PCTISE9?/OOI53 62.62'. which brins about the rotational movement of each heat accumulator ~.~'.
The motors 6'_'.6?' shall in this case be synchronized so that when the first heat accumulator ~ i~ in the first position, the second heat accumulator ~' shall be in the second position and vice versa This synchronization can take place by a control unit 60. Alternatively, the heat recovery unit can be equipped with only one motor, where the rotational movement of the motor is transmitted to each of the shafts of the heat accumulators by a gear or a link mechanism (not shown).
During exhaust air throuehflow when the first heat accumulator ~ is set in the first position. air at room temperature in the form of e.~chaust air flows in through the exhaust air opening 1~ and into the first chamber 40, in which the first heat accu-mulator ~ is positioned. The exhaust air flows subsequently through the heat accu-mulator 5 in a direction which substantially corresponds to the direction of its thick-ness. the heat accumulator ~ is thereby heated up by the throuQhflowing exhaust air. The air then flows out through the used-air opening ?~ in the form of used air och consequenti~- leaves the first chamber =10. The used air which leaves the used-air opening 25 can then suitably flow into a channel 82 (Figure ~), which transports the air out of the building.
At the same time as e.~chaust air throughflow takes place in the first chamber 40.
exterior air throu~hflow takes place in the second chamber 4~, in which the second heat accumulator ~' is set in the second position far exterior air throuQhflow. Durine exterior air throuQhflow exterior air flows in through the exterior air opening 20 and into the second chamber ~~. The exterior air then flows through the second heat 2~ accumulator ~~ in a direction which essentially coincides with the direction of its thickness. The e~cterior air is thereby heated up by the second heat accumulator ~' which earlier has been warmed up by exhaust air during exhaust air throuahflow.
The air then flows out through the supply air opening 10 in the form of supply air and consequently leaves the second chamber ~1~. The supply air which leaves the supply air opening 10 then flows either directly into the building or into a tube system which distributes the air to the different rooms in the building (not shown).
According to this embodiment according to Figure 3, a control means for control-Tina the heat recovery unit can be constructed so that a first sensor >j senses the temperature of the exterior air which is flowing into the exterior air opening 20.
This first sensor 5~ is connected to a control unit 60, and is compensated.
which means that it gives signals to the control unit 60 which signals are the basis for how the heat recovery unit is to be regulated at different exterior temperatures.
A second i0 sensor ~7 whi~h i.s placed by the supply air opening 10 and connected to the control unit 60 senses the temperature of the warmed up supply air which leaves the supply air openings 10 ~f the respective chamber ~0,4~. This second sensor ~7 is regulated.
which means that it gives sisals to the control unit 60 which signals are a basis for how the heat recovery unit should be reeulated with respect to a suitably installed 1 ~ desired value which is programmed into the control unit. Vtrhen the supply air temperature is below the desired value of the second sensor ~7, the control unit 60 gives a sisal to the respective stepping motor 62,62', which are connected to the respective shafr 30,30' of the heat accumulators ~.~', whereby the first motor rotates the first heat accumulator ~ to the second position for exterior air throuah-20 flow. At the same time the second stepping motor 62' rotates the second heat accumulator ~' to the first position for exhaust air throughflow.
As an alternative the f rst sensor 5~ senses the temperature of the used air which leaves the used-air openings 2~ of the respective chamber 40.4. A reference sensor can. for example, be placed in the building which is to be ventilated, in order to sense the room temperature in the building. The first sensorp3 and the reference sensor are connected to the control unit 60. The second sensor p7 is placed by the supply air openings 10 of the respective chamber X0,45 and is connected to the control unit 60. whereby the second sensor ~7 senses the temperature of the warmed W('? 97/28412 I 2 PCT/SE97/00153 up supply air. When the difference between the temperatures sensed by the first and second sensors 55 and respectively 57 and the temperature sensed by the reference sensor 56 reaches a predetermined value, the control unit 60 gives a signal to the first and second stepping motors 62.62'. whereby the first motor 62 rotates the first heat accumulator ~ to the second position for exterior air throughflow. At the same time the second stepping motor 62' rotates the second heat accumulator ~' to the first position for exhaust air throughflow.
Figure ~ shows a lateral view of a heat recovew unit according to the second I O embodiment. The first heat accumulator ~ is shown with a plurality of parallel lines which extend in the direction of thickness of the first heat accumulator ~.
The parallel lines symbolize that the first heat accumulator ~ is built up by a plurality of plates 37. The solid arrows show exhaust air flows through the heat recovery assembly. The first heat accumulator 6 is set in the first position for the exhaust air 16 throuQhflow, wherein exhaust air flows through the exhaust air opening I S
into the first chamber X10, through the first heat accumulator ~ and out through the used-air opening ?5 in the form of used air.
The second heat accumulator ~' is hidden behind the wall SO which separates the 20 first and second chambers X0,45. thus the contours of the second heat accumulator are only shown with dashed lines. The second heat accumulator 5' is set in the second position for exterior air throughflow which is shown with dashed arrows.
A fan part 66 which comprises two fans 66_67 is connected to the supply air opening 25 10 and the used-air opening 35, and a filter part 70 which comprises two filters 71.
72 is connected to the exhaust air opening 1 ~ and the exterior air opening 20.
Figure ~ shows an example of the application of a heat recovery unit according to the second embodiment. The heat recovery unit can_ for example. be placed in an WO 97!28412 1 ~ PGT/5E9?!00153 isolated place in a building 79. However. it is also possible to place the heat reco-ven~ unit outside the building 79. Exhaust air F in the form of the interior air of the building 79 is led through an exhaust air channel 80 into the filter part 70 of the heat recoven~ unit and further in through the e,Yhaust air opening 15 to one of the two s chambers 40 alt. 4~; which each contain a heat accumulator ~,~'. The exhaust air passes through one of the heat accumulators 5,5' and out through the used-air opening 2~ in the form of used air A which is led through a used-air channel 82 in order to be let out outside the building 79. At the same time. exterior air U
is led through an exterior air channel 84 into the filter part 70 of the heat recovery unit and further in through the exterior air opening ?0 to the second one of the two chambers 40 alt. 4~. The e:cterior air passes through the second of the two heat accumulators ~
,5' and out through the supply air opening 10 in the form of supply air T, which is led through a supply air channel 86 in order to be let into the building 79.
1~ Figure 6 shows a heat recovery unit according to Figure 4 where both the first and the second heat accumulators ~,~' are in a third position, in which position neither of the openings 10-2S in the casino 1 of the heat recovery unit are closed by means of the end faces 3 ~ of the heat accumulators ~.~'. On the other hand both the exterior openings 20 and the used-air openings 2~ are closed by means of valve leaves 90 which prevent exterior air to flaw from the exterior air opening 20 and the exhaust air opening 25 to the supply air opening 10. In the third position, exhaust air can flow from the exhaust air opening 1S to the supply air opening without passing through the heat accumulators S,S', whereby an internal air circu-lotion in, for example, a building can be achieved. The third position can be taken ?S during, for example. a power cut or during night or weekend stoppages. when the stepping motors which bring about the rotational movement of the heat accumula-tors ~.~' can be so designed that they automatically rotate the heat accumulators S.S' to the third position during shutdowns.
Fieure 7 shows a lateral view of a heat recovery unit according to a third embodi-ment. The first heat accumulator ~ here is tipped into the second position for exterior air throughflow. At the same time the second heat accumulator ~' is tipped into the first position for exhaust air throughflow. Each of the heat accumulators ~.~' is partitioned with a dividing wall 9~. which e;ctends in the direction of thick-ness of the heat accumulators ~,~', whereby this dividing wall 9~ cooperates with valve leaves 96, which are synchronized with the rotational movement of the asso-ciated heat accumulator ~.~'. This synchronization can. for example. be achieved by means of a link system (not shown). The dividing wall 95 and the valve iPaves 96 can together cooperate in order to minimize the losses in the heat recovery when the heat accumulators ~,~' rotatate from the first to the second position. and vice versa. Another object of the dividing wall 95 and the valve leaves 96 will be explained in connection with Figure 8.
1 ~ Figure 8 shows a heat recovery unit according to Figure 7, where both the first and the second heat accumulators ~.~' are in a third position, in which position none of the openings I 0-25 in the casing I of the heat recovery unit are closed by means of the end faces 3~ of the heat accumulators ~.~'. By means of the dividing wall 95 and the valve leaves 96, however, two, from each other separated. substantially airtight ?0 spaces are formed on each side of the dividing wall 95 and the valve leaves 96.
Consequently. e.chaust air can flow through the e;chaust air opening 1 ~ and out throu~ll the supply air opening 10, whereby a recycle air function in the form of an intemaI air circulation is achieved in, for example, a building. As described in connection with Figure 6, the third position can be taken during, for example, 25 power failures.
In the summer months when the e;cterior air temperature is relatively high.
the accumulators ~,~' in the heat recovery unit can remain in either the first or the second position for a long time. A time function built into the control unit 60 can WO 97/28412 I 7 PCTISE9'7100153 then ''exercise' the rotational function at regular time intervals. for example one rotation or tipping per day. whereby the movable parts of the heat recovery unit are brought into motion in order to prevent them from sticking. -An advantage of the heat recovery unit according to the invention is that it can be applied at a long distance from an outer wall in a building, as the air the whole time flows in the same direction in the channels 80-86 which are connected to the heat recovery unit.
14 Another advantage of the heat recovery unit is that if the rotating shafr 30 of the heat accumulator ~.~' is placed horizontally, exhaust air will flow substantially upwards through the heat accumulator ~_~'. This means that water which condenses on the heat absorbing surfaces of the heat accumulator 5,~' will stay there and in the second position of the accumulator will be absorbed by the exterior air which flows 1 ~ through the heat accumulator 5.~'. Consequently, no thaw water piping for the heat recovery unit is required. The efficiency of the heat recovery unit is also increased in this way because latent heat. which from the beginning is contained in the water vapour, is recovered.
20 Yet another advantage of the heat recovery unit according to the invention is that the heat accumulator ~,~' is easy to clean because the throuahflow direction of the air through the heat accumulator 5,5' occurs substantially in the direction of its thickness which is considerably less than its length and width, so that the throughflow channels are short and easy to clean by e.g. by rinsing with water.
Yet another advantage of the heat recovery unit according to the present invention is that the sound change during the change from the exterior air throuahflow to the exhaust air throuehflow and vice versa is very low. According to the invention, air flows the whole time in the same direction through the openings 10-?~ in the casino I and in the channels 80-86 which are connected thereto. which means that the sound chance is low because no large air volume has to chance direction of flow.
Yet another advantage of the heat recovery unit according to the present invention is that the pressure drop over the heat accumulator ~.~' is low because the path of the air through the heat accumulator ~,~' is relatively short. 'This means that a Lower fan capacity is required in order to produce the flow of the air and it also means a lower sound level.
It has been described above how heat can be recovered by the heat recovery unit according to the invention. It is: however, possible by means of the heat recovery unit to shut out warm air from, for example, a building in which the indoor tempera-ture should be less than the outdoor temperature. The heat recovery unit will then 1 ~ work the other way round, whereby warm exterior air will give off its heat to the heat accumulator 5,5' which has been cooled by the .exhaust air throughflow.
The exterior air will thus be cooled down and flow into the rooms of the building in the. form of cool supply air.
The foregoing description of the preferred embodiments of the present invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application. Many modifications, variations and adaptations are possible without departing from the scope of the invention.
Claims (16)
1. A heat recovery unit, comprising:
a casing;
a pair of exhaust airflow openings provided in the casing;
a pair of supply airflow openings provided in the casing;
a regenerative heat accumulator having two parallel end faces, the regenerative heat accumulator being housed by the casing, and the regenerative heat accumulator rotatable about an axis of rotation perpendicular to a normal direction of the end faces from a first position in which the end faces cover the pair of exhaust airflow openings and leave open the pair of supply airflow openings to a second position in which the end faces cover the pair of supply airflow openings and leave open the pair of exhaust airflow openings.
a casing;
a pair of exhaust airflow openings provided in the casing;
a pair of supply airflow openings provided in the casing;
a regenerative heat accumulator having two parallel end faces, the regenerative heat accumulator being housed by the casing, and the regenerative heat accumulator rotatable about an axis of rotation perpendicular to a normal direction of the end faces from a first position in which the end faces cover the pair of exhaust airflow openings and leave open the pair of supply airflow openings to a second position in which the end faces cover the pair of supply airflow openings and leave open the pair of exhaust airflow openings.
2. The heat recovery unit of claim 1, wherein the pair of exhaust airflow openings comprises an exhaust air opening and a used air opening.
3. The heat recovery unit of claim 2, wherein the pair of supply airflow openings comprises a supply air opening and an exterior air opening
4. The heat recovery unit of claim 1, wherein the regenerative heat accumulator has a length, a width and a thickness, the thickness being substantially less than the length and wherein air passes through the regenerative heat accumulator in a direction of the thickness.
5. The heat recovery unit of claim 4, wherein the axis of rotation is substantially perpendicular to a direction of thickness and substantially perpendicular to a direction of length.
6. The heat recovery unit of any one of claims 1 to 5, wherein the end faces of the regenerative heat accumulator are substantially planar.
7. The heat recovery unit of any one of claims 1 to 6, wherein the casing has first and second substantially planar ends, the first end including one exhaust airflow opening and one supply airflow opening and the second end including the remaining exhaust airflow opening and the remaining supply airflow opening.
8. The heat recovery unit of any one of claims 1 to 6, wherein the end faces of the regenerative heat accumulator have sealing strips cooperating with ends of the casing.
9. The heat recovery unit of claim 3, further comprising valve leaves and wherein the regenerative heat accumulator can be placed in a third position in which exhaust air can flow from the exhaust air opening to the air supply opening and the valve leaves prevent airflow through the exterior air opening and the used air opening.
10. The heat recovery unit of any one of claims 1 to 9, wherein exhaust airflow and exterior airflow are arranged to flow in opposite directions through the regenerative heat accumulator.
11. The heat recovery unit of claim 4, further comprising: valve leaves which are synchronized with rotational movement of the regenerative heat accumulator;
and a dividing wall extending in the direction of the thickness of the regenerative heat accumulator, the dividing wall cooperating with the valve leaves so that when the regenerative heat accumulator is in a third position, two separate substantially airtight spaces are formed on each side of the dividing wall and the valve leaves.
and a dividing wall extending in the direction of the thickness of the regenerative heat accumulator, the dividing wall cooperating with the valve leaves so that when the regenerative heat accumulator is in a third position, two separate substantially airtight spaces are formed on each side of the dividing wall and the valve leaves.
12. The heat recovery unit of claim 3, further comprising a first sensor provided at the used air opening for sensing a temperature of the used air, a second sensor provided at the supply air opening for sensing a temperature of the supply air and a reference sensor provided in an air volume to be ventilated for sensing a temperature of the air volume, and wherein the first and second sensors and the reference sensor each are connected to a control unit that controls rotational movement of the regenerative heat accumulator based on the temperature which each of the sensors senses.
13. The heat recovery unit of claim 3, further comprising a second regenerative heat accumulator and wherein the casing comprises a wall defining two chambers inside the casing, each chamber contains one regenerative heat accumulator, each of the openings is connected with both chambers and wherein rotational movement of the regenerative heat accumulators is controlled so that when the first regenerative heat accumulator is in the first position, the second regenerative heat accumulator is in the second position and vice versa.
14. The heat recovery unit of claim 2, further including a fan part comprising two fans, the fan part being connected to the supply air opening and to the used air opening.
15. The heat recovery unit of claim 3, further including a filter part comprising two filters, the filter part being connected to the exhaust air opening and the exterior air opening.
16. A heat recovery assembly comprising two regenerative heat recovery units as defined in claim 3, the regenerative heat recovery units being coupled together so that the openings of the respective heat recovery unit are joined to each other and wherein rotational movements of the regenerative heat accumulators are controlled so that when the regenerative heat accumulator in one of the heat recovery units is in the first position, the regenerative heat accumulator in the other heat recovery unit is in the second position and vice versa.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9600390-0 | 1996-02-02 | ||
| SE9600390A SE508957C2 (en) | 1996-02-02 | 1996-02-02 | Regenerative heat recovery unit comprising a heat accumulator which, through a pivotal movement, exhibits a damper function and heat recovery unit with two connected heat recovery units |
| PCT/SE1997/000153 WO1997028412A1 (en) | 1996-02-02 | 1997-01-31 | Regenerative heat recovery unit comprising heat accumulators tiltably movable to have a valve function |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2244064A1 CA2244064A1 (en) | 1997-08-07 |
| CA2244064C true CA2244064C (en) | 2006-01-24 |
Family
ID=29422560
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2244064 Expired - Fee Related CA2244064C (en) | 1996-02-02 | 1997-01-31 | Regenerative heat recovery unit comprising heat accumulators tiltably movable to have a valve function |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2244064C (en) |
-
1997
- 1997-01-31 CA CA 2244064 patent/CA2244064C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2244064A1 (en) | 1997-08-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20140131 |