U.S. patent application number 14/440858 was filed with the patent office on 2015-11-12 for a heat exchanger and a ventilation assembly comprising it.
This patent application is currently assigned to ANDRI ENGINEERING AB. The applicant listed for this patent is ANDRI ENGINEERING AB. Invention is credited to Peter Wallin.
Application Number | 20150323216 14/440858 |
Document ID | / |
Family ID | 50685340 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150323216 |
Kind Code |
A1 |
Wallin; Peter |
November 12, 2015 |
A HEAT EXCHANGER AND A VENTILATION ASSEMBLY COMPRISING IT
Abstract
A heat exchanger includes two sets of channels arranged adjacent
to each other, for beat exchange between a first and a second air
stream. Each of the sets of channels includes at least one
transversal drainage channel for drainage of condensate, and a
ventilation assembly including such a heat exchanger.
Inventors: |
Wallin; Peter; (Kalmar,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ANDRI ENGINEERING AB |
Kalmar |
|
SE |
|
|
Assignee: |
ANDRI ENGINEERING AB
Kalmar
SE
|
Family ID: |
50685340 |
Appl. No.: |
14/440858 |
Filed: |
November 7, 2013 |
PCT Filed: |
November 7, 2013 |
PCT NO: |
PCT/SE2013/051315 |
371 Date: |
May 5, 2015 |
Current U.S.
Class: |
62/314 ; 165/41;
165/71 |
Current CPC
Class: |
F28D 5/00 20130101; F25D
21/14 20130101; F28F 17/005 20130101; F24F 12/002 20130101; F24F
5/0035 20130101; F28D 9/0031 20130101; F28D 21/0014 20130101; F28F
3/046 20130101; F28F 2245/04 20130101; F24F 13/222 20130101 |
International
Class: |
F24F 12/00 20060101
F24F012/00; F24F 5/00 20060101 F24F005/00; F25D 21/14 20060101
F25D021/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2012 |
SE |
1251263-8 |
Claims
1. A heat exchanger comprising two sets of channels arranged
adjacent to each other for heat exchange between a first and a
second air stream, wherein each of the sets of channels comprise at
least one transversal drainage channel for drainage of
condensate.
2. The heat exchanger according to claim 1, wherein the drainage
channels are substantially vertical.
3. The heat exchanger according to claim 1, wherein the channels
have inside surfaces with a hydrophobic surface layer.
4. The heat exchanger according to claim 3, wherein the surface
layer has a nanostructure.
5. The heat exchanger according to claim 1, wherein each set of
channels for the air streams form an angle with the horizontal
plane of 0 to 30.degree..
6. The heat exchanger according to claim 1 , wherein the drainage
channels are connected to a collecting vessel.
7. A ventilation assembly comprising a heat exchanger according to
claim 1.
8. The ventilation assembly according to claim 7, wherein the first
and the second air streams are intake air and exhaust air,
respectively, and in that means are arranged for evaporative
cooling of the exhaust air before it is led into the channels of
the heat exchanger.
9. The ventilation assembly according to claim 7, wherein means are
arranged for shifting between evaporative cooling of the intake air
and the exhaust air, respectively.
10. The ventilation assembly according to claim 7, wherein a mist
generator is arranged in order to obtain the evaporative cooling.
Description
BACKGROUND AND SUMMARY
[0001] The present invention relates according to an aspect thereof
to a heat exchanger comprising two sets of channels arranged
adjacent, to each other for heat exchange between a first and a
second air stream. The invention also relates according to an
aspect thereof to a ventilation assembly.
[0002] In order to obtain maximum heat recovery from outgoing
in-house air when having a balanced housing ventilation most often
heat exchangers are used having parallel, vertically arranged
plates, e.g. made from thin plastic or aluminum, and wherein the
heat exchanging surface is maximized by designing the plates with
channels with outgoing in-house air (exhaust air) and incoming air
from the outside (intake air) in counter-now. A usual geometry is a
plate thickness of 0.1-0.5 mm, a distance between the plates 1.5-5
mm and a channel width (channel height) of 2-5 mm.
[0003] When the outside temperature is substantially lower than the
room temperature the moisture of the room air will condense in the
exhaust air channels of the heat exchanger and will sometimes cause
clogging of water droplets resulting in an increase of the air
resistance at the exhaust air side of the heat exchanger. At
outside temperatures below -2.degree. to -4.degree. C. the
condensate will freeze in the room air channels of the heat
exchanger so that efficiency deteriorating measures have to be
taken, such as introducing additional electric heating in the heat
exchanger.
[0004] During winter time the outside air contain in absolute
numbers (grams water/kilogram, air) very little moisture, which
results in that the indoor climate will be dry. Moistening of the
heated air will lower its temperature, which means either a too low
blowing-in temperature with supply of heat of vaporization from the
room air, or in that the supply air has to be post-heated before
blowing it into the room. The problem with too dry air during the
winter time is advantageously solved by integrating an aerosol
generator in order to increase the moisture content of the supply
air in the construction with the technique that is described in the
Swedish patent No. SE 534 398 C2.
[0005] In the summer time, when sometimes there is a need of
cooling, the heat exchanger may give an undesired heating of the
intake air through heat transfer from warm exhaust air, which has
been heated by people and equipment indoors. A frequent solution to
this problem is to arrange a thermostatically or manually operated
by-pass channel for the exhaust air, internally in the ventilation
assembly or as an addition to the assembly. This will, however,
result in a more complicated and thus more bulky and mote cost
demanding construction, while at the same time the need for
occasional cooling of the intake air, if the temperature outside is
high, remains. Further, during certain temperature and moisture
conditions a clogging of water droplets might occur on the intake
air side of the heat exchanger with accompanying increase of the
air resistance.
[0006] Thus, there is a desire to provide a heat exchanger and a
ventilation assembly lacking the above drawbacks, not least
regarding the undesired increase of the air resistance.
[0007] According to an aspect of the invention, an exchanger is
characterized, in that each of the sets of channels comprise at
least one cross-directional drainage channel for draining off
condensate.
[0008] A ventilation assembly can comprise a heat exchanger
according to the above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention will now be described with reference to the
accompany in g drawings, on which;
[0010] FIG. 1A shows a partly cut up view in perspective of a heat
exchanger according to one embodiment of the invention;
[0011] FIG. 1B shows a view corresponding to the view in FIG. 1A of
a second embodiment of the heat exchanger according to the
invention;
[0012] FIG. 2 shows a cross-sectional view along a horizontal plane
through a pan of the heat exchanger;
[0013] FIG. 3A shows a partly cut up view of the heat exchanger
according to the invention;
[0014] FIG. 3B shows a view corresponding to the view in FIG. 3A of
one detail of the heat exchanger; and
[0015] FIG. 4 shows a principal outline of a ventilation assembly
according to the invention.
DETAILED DESCRIPTION
[0016] FIG. 1A shows a first embodiment of a heat exchanger 25,
which comprises a number of pleated plates 1, which are mounted
between smooth plates 2. The pleated plates 1 can in principal also
be comprised of a larger number of thin ribs, being arranged to
form an angle in relation to each other, in order to build up the
pleated structure. Hereby are formed two sets of adjacent channels
5, 6 for outgoing room air (exhaust air) and incoming outside air
(intake air).
[0017] The pleated plate 1 has according to a preferred, embodiment
of the invention at least one flattening 26 forming drainage
channels 4 for condensation water, one on each side of the
flattening 26, for the two sets of channels 5,6. The drainage
channels 4 might have varying designs, having in common that the
two sets of channels 5, 6 remain closed in relation to each other,
so that the two air streams with exhaust air and intake air,
respectively, are not mixed.
[0018] The object of the drainage channels 4 is that condensed
moisture from the respective air stream shall be led from the
channels 5, 6 to the respective drainage channel 4, and flow to a
collecting vessel 19. The drainage channels 4 are therefore
advantageously upright, preferably substantially vertical, while
the channels 5, 6 preferably form an angle with a horizontal plane,
so that droplets of condensed moisture in the channels 5,6 are made
to flow in a direction towards one or the drainage channels 4. When
the condensate droplets arrive at some of the drainage channels 4
they will flow downwards along the flattening 26 or some of the
other walls in the drainage channel 4, and finally be guided down
into a collecting vessel 19 (see FIG. 4), Condensate will fall out
both in contact with the walls of the channels 5, 6 and in contact
with the walls of the drainage channels 4, but irrespective of
where the condensation takes place, the condensate shall be guided
to the collecting vessel 19.
[0019] FIG. 1B shows a second embodiment of the invention with
plates 1 with pleats or cavities, mounted in such a way that
channels 5 for outgoing room air and 6 for incoming outside air
lying adjacent to each other are formed between the plates. The
plates 1 according to the invention shown here also have a
flattening 4 forming vertical drainage channels for condensed
water. The pleated plate or plates 1 are surrounded by external,
smooth plates 2, which are not shown in FIG. 1B.
[0020] FIG. 2 shows a cross section in a horizontal plane through,
the area around the flattening 4 and shows how the room air
(exhaust air) 5A, and the incoming outside air (intake air) 6A in
counter flow are fed on either side of the flattened part 26 of the
heat exchanger plate 1. For the sake of clarity it should be noted
that the two air streams 5A, 6A are somewhat displaced in view of
each other in a direction perpendicular to the plane of the
drawing, and they are separated so that the air streams 5A, 6A are
not mixed with each other. In that way an efficient transport of
two air volumes take place, so that an exchange of the air in the
ventilated space takes place.
[0021] However, a transfer of heat can take place from one of the
air streams 5A to the other 6A, through the thin walls of the
pleated plate 1, which are manufactured in such a material and with
such a thickness that heat transfer is favored.
[0022] FIG. 3 A shows a planar view of the room air side (exhaust
air side) of a heat exchanger plate 1. The upper and lower edges 8,
27 and the channels 5, 6 of the plate 1 form an angle in relation
to a horizontal plane, so that condensate in the channels 5, 6
under the gravitational effect is brought to flow in a direction
towards the flattened parts 26, being parts of the drainage
channels 4A, 4B and 4C. In their upper edge 9 all heat exchanger
plates 1 are sealed against the surroundings, in the lower edge 27
on the room air side there is a water collecting channel 9 with an
outlet opening 10 between the plates, and on the intake side there
is a corresponding water collecting channel 11 with an outlet
opening 12 between the plates 1. The outlet openings 10 and 12 are
connected to transversal collecting channels 13, 14. The condensate
flows down into a water collecting channel 9 at the lower edge 27
of the plate 1 and finally out through, a channel 13.
[0023] FIG. 3B shows a corresponding detail of the intake side with
a channel 11 for water collecting and a channel 14, which are
separate from corresponding details of the exhaust side in order to
guarantee that the air streams 5A, 6A do not get mixed with each
other.
[0024] With this suggested design of the heat exchanger plates the
condense water of the room air will be removed from the air
channels before the water reaches zones where there is a risk that
the water freezes.
[0025] The heat exchanger plates 1 have completely or partly been
given a hydrophobic surface structure, which facilitates the
drainage, since the adherence of the condensed water to the
surfaces decreases, and in that droplets are more easily formed.
The surface of the condensed water towards the surrounding air is
also reduced and the risk for the condensed water to vaporize anew
is reduced, which in turn leads to a more efficient
dehumidification of the air streams 5A, 6A, which move through the
heat exchanger. Further, the heat exchanger has been designed with
one or several vertical drainage channels 4 for leading away of the
condensed water, in that way the need of additional heating in the
beat exchanger can be avoided completely or partly and the total
efficiency of the heat exchanger will be higher.
[0026] The hydrophobic surface structure can be achieved in a
number of different ways. One way is to give the surface a
nanostructure by coating the surfaces with a suitable agent. For
plastic surfaces it could be an agent containing silicon compounds
so that silicon crystals are formed, which clog microscopic pores
which could exist in the surface of a plastic material. Another way
to achieve a nanostructure is to emboss it in the surface during
the manufacture of the walls of the channels 4, 5, 6.
[0027] FIG. 4 shows a cross-section (principal view) of a
ventilation assembly 28 according to the invention, wherein heat
exchanger plates 1 according to the above are comprised. The room
air (exhaust air) 5A is filtered in the filter 15 and the incoming
outside air (intake air) in the filter 16.
[0028] Condensed water from the exhaust air 5A is collected in the
channel 13 and any condensate from the outside air 6A (in a warm,
moist climate) is collected in the channel 14. From the channels 13
and 14 condensed water is fed through pipes or hoses 17, 18 down so
far under the surface in a water vessel 19 that air passage between
the pipes 17 and 18 is prevented.
[0029] The vessel 19 is assembled with a water vessel 20 in which
are arranged piezoelectric ultrasound generators 21 and 22, which
in the preferred embodiment are two in number. The ultrasound
generators 21 and 22 can be operated separately each on their own
(50 % capacity) or both together (100 % capacity). The water
aerosol which is formed in the collector 23 can, according to the
Swedish patent No. SE 534 398 C2, be conducted to the intake air
inlet 29 or the heat, exchanger 25 between the heat exchanger 25
and a filter 16, wherein the aerosol with the aid of the cold air
stream 6A is transported into the heat exchanger 25 in order to be
able to be evaporated therein with the aid of heat from the exhaust
air 5A.
[0030] In the ventilation assembly 28 according to an aspect of the
invention is optionally also used an evaporative cooling of the
exhaust air 5A by supplying a water aerosol to the exhaust air 5A
between the heat exchanger 25 and a filter 15. The object of this
is to accomplish drainage of heat from too hot intake air 6A, for
example during the summer months. In addition to the reduction of
the intake air 6A temperature, also its humidity can be lowered by
the deposit of condensate on the inner surfaces of the channels 6
and which is led from the heat exchanger 25 and down into the
collecting vessel 19 in the above described way
[0031] The aerosol from the ultrasound generators 21 and 22 are fed
to the exhaust air inlet 30 by change-over of a control valve 24,
wherein it is evaporated and accordingly cools down, the exhaust
air 5A flowing into the heat exchanger 25.
[0032] With a ventilation assembly 28 according to an aspect of the
invention the problem with too dry air is avoided during wintertime
by the integration of the ultrasound, generators 21, 22, which
establish an aerosol for humidifying the intake air 6A, in the
construction with the technology described in the Swedish patent
No. SE 534 398 C2.
[0033] Novel features of the ventilation assembly 28 according to
an aspect of the invention, include that the ultrasound generators
21,22 here are also used for evaporative cooling of the exhaust air
5A with the evaporation heat taken from the condensation heat of
the exhaust air. Condensate in the channels 5,6 is led out to the
drainage channels 4, and clogging of the channels because of water
droplets, or freezing of the condensate in the channels 5, 6 is
prevented thereby.
[0034] In one connection part 7A the room air (exhaust air) 5A
corning to the heat exchanger 25 is distributed over all the
channels of the heat exchanger plate 1 on its front side to be
conducted through these to the opposite connection part 7B.
Incoming outside air (intake air) 6A is distributed to the channels
on the backside of the plate and is conducted out in the connection
part 7A. The connection parts 7A, 7B are so designed that room air
5A flowing in to and outside air 6A flowing out from the heat
exchanger 25 exchange heat in cross flow like the room air 5A
flowing out and the outside air 6A flowing in.
[0035] If condensate has formed in the room air channels 5 it will
flow down onto the flattened part 26 or the heat exchanger plate 1
and will thus not be transported further to colder parts of the
heat exchanger plate. If continued condensation occurs at the
further transport of room air towards the connection part 7B, this
condensed water can be drained in several drainage channels 4B and
4C, closer to the outlet of the room air. If condensation occurs on
the intake air side of the heat exchanger plates 1, this condensed
water can be drained in the corresponding way.
[0036] The condensed water in the channels 4 can on the room air
side freely flow out through the opening 10 down into the
transversal collecting channel 13. During summertime, at
evaporative cooling of the exhaust air 5A, moisture in the incoming
outside air 6A condenses on the intake air side of the heat
exchanger plates 1 and there it flows out through the opening 12,
and down into the transversal collecting channel 14.
[0037] Discharge of condensed water down, into the channels 4 is
facilitated if the surface of the heat exchanger plate 1,
especially at the channels 4 have hydrophobic properties, e.g. with
the aid of nanotechnology, as has been discussed above. Quicker and
more complete drainage of condensed water front all air channels 5,
6 of the heat exchanger plate 1 is facilitated if the whole heat
exchanger plate 1 has corresponding hydrophobic properties. Tests
have proven that the drainage from the heat exchanger plates 1 can
be further improved it the plates 1 can be vibrated with
aerodynamic or mechanical appliances.
* * * * *