Note: Descriptions are shown in the official language in which they were submitted.
CA 02260228 1998-12-30
Air-conditioning installation
The present invention relates to an air-
conditioning installation according to the preamble of
claim 1.
An air-conditioning installation of this type
is known, for example, from GB Patent No. 601023. This
air-conditioning installation has a heat exchanger with
two flow channel systems, one flow channel system
having a first fluid stream flowing through it and, at
the same time, the other flow channel system having a
second fluid stream flowing through it. The first fluid
stream is formed by used-up waste air which is
withdrawn from a room. The second fluid stream is
outside air which is taken in from the surroundings and
is heated by the first fluid stream in the heat
exchanger. Downstream of the heat exchanger, as seen in
the direction of flow of the first fluid stream, part
of the first fluid stream, which is controlled by a
flap, is redirected and mixed with the heated, second
fluid stream on the room side of the heat exchanger in
order to be supplied to the room therewith. An air-
conditioning installation of this type, which acts as a
recuperator, is suitable, in particular, for air-
conditioning rooms in a Central European climate inbetween seasons. Furthermore, the bypass connection
allows the installation to be regulated easily to this
effect. However, it has been found that air-
conditioning installations of this type are not
optimally suitable for use in the case of low and
relatively high ambient temperatures.
An air-conditioning installation of a different
type is known from DE-A-26 34 449 and the corresponding
GB Patent No. 155 505. This air-conditioning
installation has two heat accumulators each with a flow
channel system. Controlled by a flap system, the first
fluid stream flows through the flow channel system of
one heat accumulator for a specific period of time and
then flows through the flow channel system of the other
heat accumulator for a further period of time, this
CA 02260228 1998-12-30
alternating with the second fluid stream. The fluid
stream with the higher temperature thus heats the heat
accumulator which it flows through, and this heat
accumulator then discharges said heat to the fluid
stream with the lower temperature, in order to heat the
same. Such air-conditioning installations, also
referred to as regenerators, have an extremely good
efficiency and are suitable, in particular, for use in
the case of cold and relatively high ambient
temperatures, for the purpose of air-conditioning
rooms. In between seasons, these installations have the
disadvantage, in particular, that moisture is also
recovered when it is not desired.
Furthermore, EP-A-0 167 938 discloses a heat-
exchanger and/or heat-accumulator body for use either
in accordance with the recuperator principle or in
accordance with the regenerator principle. The body
comprises a stack of hollow-chamber plates, it being
the intention for successive plates to be arranged in
each case with mutually perpendicular channels for use
in accordance with the recuperator principle and with
mutually parallel channels for use in accordance with
the regenerator principle.
Taking this prior art as the departure point,
an object of the present invention is to provide an
air-conditioning installation of the generic type which
can be used with optimum efficiency in a large ambient-
temperature range.
This object is achieved by an air-conditioning
installation which has the features of claim 1.
The air-conditioning installation according to
the invention can be operated both with recuperative
action and with regenerative action. In the two modes
of operation, use is made of the same heat-recovery
units, which in one case serve as a heat exchanger and
in the other case serve as a heat accumulator. An air-
conditioning installation which, from low to high
ambient temperatures, can be used optimally for room
air-conditioning is provided by way of just an
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CA 02260228 1998-12-30
extremely small amount of additional outlay, in
relation to the known air-conditioning installations.
Preferred embodiments of the air-conditioning
installation according to the invention are specified
in the dependent claims.
The invention will now be explained in more
detail with reference to an exemplary embodiment
illustrated in the drawing, in which, purely
schematically:
Figure 1 shows a view of an air-conditioning
installation according to the invention with the front
wall of the housing assumed as being transparent;
Figure 2 shows a plan view of the air-
conditioning installation shown in Figure 1, with the
top wall assumed as being transparent;
Figure 3 shows a view of the air-conditioning
installation shown in Figures 1 and 2, with a chain-
dotted representation of the progression of the fluid
streams in recuperative operation;
Figure 4 shows a plan view of the air-
conditioning installation shown in Figures 1 and 2,
with a chain-dotted representation of the progression
of the fluid streams in recuperative operation;
Figure 5 shows, in an illustration which is the
same as Figure 1, the air-conditioning installation in
regenerative operation, with a chain-dotted
representation of the progression of one fluid stream
through one heat-recovery unit during one operating
phase;
Figure 6 shows, in an illustration which is the
same as Figure 5, the air-conditioning installation
with a chain-dotted representation of the progression
of the other fluid stream through the other heat-
recovery unit during the same operating phase; and
Figure 7 shows, in an illustration which is the
same as Figure 2, the air-conditioning installation
with a chain-dotted representation of the progression
of the two fluid streams during the same operating
phase as in Figures 5 and 6.
CA 02260228 1998-12-30
-- 4
The air-conditioning installation shown in
Figures 1 and 2 has two heat-recovery units 10, 12 each
comprising two cross-flow plate heat exchangers 10',
10'' and 12', 12'' respectively, which are arranged
directly one behind the other, as seen in the
longitudinal direction L of the air-conditioning
installation. Each heat-recovery unit 10, 12 thus has a
first flow channel system 14 which runs through the two
plate heat exchangers 10', 10'' and 12', 12'' in the
longitudinal direction L, and a second flow channel
system 16. The latter comprises channels 16' which run,
in each plate heat exchanger 10', 10'', 12', 12'' at
right angles to the first flow channel system 14, it
being the case that the channels 16' of the cross-flow
plate heat exchangers 10', 10'', 12', 12'', which are
respectively assigned to a heat-recovery unit 10, 12,
are connected in series by means of an intercepting and
deflecting basin 18 arranged therebeneath, with the
result that the corresponding fluid stream is routed in
the form of a V through the heat-recovery unit 10 or
12.
The air-conditioning installation has a
cuboidal housing 20 which lies horizontally and of
which the interior, as seen in the longitudinal
direction L, is subdivided, by a first transverse wall
22 and a second transverse wall 24, into two end
sections 26, 28 and a central section 30, arranged
between the transverse wall 22, 24. The central section
is subdivided into two adjacent central parts 34, 34'
by a vertical central-section intermediate wall 32,
which runs in the longitudinal direction L. The heat-
recovery unit 10 is arranged in the first central part
34 and the heat-recovery unit 12 is arranged in the
second central part 34'. Each of the two end sections
26, 28 is subdivided into in each case two end chambers
38, 38' and 40, 40', which are arranged one above the
other, by a horizontal end-section intermediate wall
36.
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CA 02260228 1998-12-30
The end wall 42 of the housing 20, said end
wall bounding the first end section 26, has a through-
passage 44, which serves as a connection for the
outside air AU and opens out into an air filter 46,
which is arranged in the end chamber 38. Above the
connection 44, the end wall 42 has a further through-
passage, which serves as an expulsion-air connection 48
in order for the expulsion air FO flowing through the
end chamber 38' to be directed, by way of a channel
system (not shown) into the surroundings.
Similarly, the opposite end wall 42' has a
through-passage which serves as a supply-air connection
50 in order for the supply air ZU flowing out of the
end chamber 40 to be directed, by a further channel
system (not shown either), to the interior of a
building which is to be air-conditioned. Coming from
the interior of the building is a further channel
system (not shown either), which is connected to a
waste-air connection 52 which connects this channel
system to the end chamber 40'. Arranged in this end
chamber 40' are further air filters 46', which are
intended for filtering dust particles out of the waste-
air stream AB.
A ventilator 54, 54' is arranged in each of the
end chambers 40 and 40', these ventilators being
intended for feeding an outside-air/supply-air stream
56 and/or waste-air/expulsion-air stream 58 (see
Figures 3 to 7) through the heat-recovery units 10, 12.
The two heat-recovery units 10, 12 are connected to the
end chambers 38, 38' and 40, 40' via flap systems such
that they can be operated both with recuperative action
and with regenerative action. In recuperative
operation, the heat-recovery units 10, 12 serve as heat
exchangers, it being the case that the outside-
air/supply-air stream 56 is routed through the first
flow channel system 14 and, at the same time, the
waste-air/expulsion-air stream 58 is routed through the
second flow channel system 16. In regenerative
operation, the outside-air/supply-air stream 56 is
. . ~, , . , ~
CA 02260228 1998-12-30
routed such that it flows through in each case the
first and second flow channel systems 14, 16 of just
one heat-recovery unit 10 or 12 during one operating
phase lasting a specific period of time and flows
through the flow channel systems 14, 16 of just the
other heat-recovery unit 12, 10 during a following
operating phase lasting a specific period of time,
whereas the waste-air/expulsion-air stream 58 is routed
conversely. In this case, the heat-recovery units 10,
12, through which one air stream 56 and the other air
stream 58 flow alternately, serve as a heat
accumulator.
Arranged in the first transverse wall 22, on
both sides of the central-section intermediate wall 32,
is a first flap system 60, 60', which is of dynamic
design and connects the end chamber 38 to a
corresponding first connection chamber 62 or 62',
respectively, as long as the pressure in the end
chamber 38 is greater than that in the relevant first
connection chamber 62, 62'. One end of the first flow
channel system 14 of the relevant heat-recovery unit
10, 12 opens out into the first connection chamber 62,
62'. The other end of the first flow channel system 14
opens out into a second connection chamber 64 or 64'.
Located in the second transverse wall 24, between said
connection chambers 64 and 64' and the end chamber 40,
is a second flap system 66, 66' which is designed to be
motor-controlled.
On both sides of the central-section
intermediate wall 32, the end chamber 40' can be
connected to a third connection chamber 70 or 70'
respectively via a third flap system 68, 68', which is
arranged in the second transverse wall 24 and is
likewise designed to be motor-controlled. One end of
the second flow channel system 16 of the heat-recovery
unit 10 or 12 opens out into the third connection
chamber 70 or 70', respectively. At the other end, the
second flow channel systems 16 open out into a fourth
connection chamber 72 or 72' in each case. Located in
. ... .. . . . . . ...
CA 02260228 1998-12-30
the first transverse wall 22, between said fourth
connection chambers 72, 72' and the end chamber 38', is
a fourth flap system 74 or 74', respectively, which is
of dynamic design. The fourth flap systems 74, 74' are
located in the open position when the pressure in the
fourth connection chamber 72, 72' is higher than the
pressure in the end chamber 38'.
The first connection chambers 62, 62i are
separated off from the corresponding fourth connection
chambers 72, 72' by a partition wall 76 and can be
connected to one another via a further flap system 78,
which is arranged in said partition wall 76 and is
designed to be motor-controlled. In the same way, the
second connection chambers 64, 64' are separated off
from the corresponding third connection chambers 70,
70' by a further partition wall 76' and can be
connected via a further flap system 80 or 80',
respectively, which is arranged in said partition wall
76'.
20Finally, the third connection chambers 70, 70'
are separated off from the corresponding fourth
connection chambers 72, 72' by a further partition wall
82. In each case are bypass flap system 84, 84', which
is designed to be motor-controlled, is arranged in said
partition wall 82.
Located in the interior of the trough-like
intercepting and deflecting basin 18, and above the
plate heat exchangers 10'', 12'' are nozzle bars 86
which are intended for spraying with water, for
adiabatic cooling, the plate heat exchangers 10', 10''
and 12', 12'' from beneath, and the plate heat
exchangers 10'', 12'' from above in addition, as well
as the fluid stream routed through the second flow
channel system 16. The water which is not taken up by
the fluid stream flows back into the intercepting and
deflecting basin 18, where it is removed by means of a
pump 88 and supplied to the nozzle bars 86 again.
90 designates a compressor which is connected
to evaporator/condenser units 92 in the end chambers
CA 02260228 1998-12-30
38' and 40. The compressor 90 and said
evaporator/condenser units 92 form an integrated,
additional heating and cooling assembly, which can be
switched over and is designed in the manner of a heat
pump with reversible operating-fluid circulation. It
should be mentioned that, depending on the purpose for
which the air-conditioning installation is used, it is
possible to dispense with the additional heating and
cooling assembly 90, 92 or to provide a heating or
cooling assembly which cannot be switched over.
Likewise, the device for adiabatic cooling is not
essential, but it is advantageous if one is provided.
Instead of a built-in heating and/or cooling assembly,
it is also conceivable to use external heating and/or
cooling assemblies.
The way in which the air-conditioning
installation which has been described above and is
shown in Figures 1 and 2 functions will now be
described, in the different modes of operation, with
reference to Figures 3 to 7. These figures correspond
to Figures 1 and 2, and the same parts of the air-
conditioning installation are provided with the same
designations and are only included in Figures 3 to 7
insofar as is necessary to aid understanding.
Assuming that a temperature of approximately
20~C is to be maintained inside a room or building
which is to be air-conditioned, the air-conditioning
installation according to the invention is
advantageously operated as follows: in the case of
outside temperatures of approximately -20~C to
approximately +5~C in regenerative operation, from
approximately 5~C to approximately 15~C in recuperative
operation preferably with regulated heat recovery, from
approximately 15~C to approximately 25~C and, depending
on humidity, up to 32~C in recuperative operation with
adiabatic cooling, and in the case of higher
temperatures additionally with a built-in cooling
assembly; in the case of very high tropical
temperatures with high levels of humidity in the
CA 02260228 1998-12-30
outside air in regenerative operation with cold
recovery and with a built-in cooling assembly. In the
case of very low outside temperatures, or in the case
where only minimal additional quantities of heat are
released in the air-conditioned room, an additional
heating assembly may be provided. If necessary, it is
possible to install an additional heating and cooling
assembly which can be switched over.
The routing of the outside-air/supply-air
stream 56 and waste-air/expulsion-air stream 58 in
recuperative operation is shown in Figures 3 and 4. The
second and third flap systems 66, 66' and 68, 68',
respectively, are located in the open position, whereas
the further flap systems 78, 78' and 80, 80' as well as
the bypass flap system 84, 84' are located in the
closed position. If the ventilators 54, 54' are set in
operation, the first and fourth flap systems 60, 60'
and 72, 72', respectively, open automatically. The
ventilator 54 takes in outside air AU, which passes
through the air filter 46 into the end chamber 38 and,
from there, through the two first flap systems 60, 60'
into the first connection chambers 62 and 62'. From
there, the outside air flows through the first flow
channel system 14 of the heat-recovery units 10 and 12
and emerges into the second connection chambers 64,
64'. From there, the air stream passes through the
second flap systems 66, 66', which are open, into the
end chamber 40, where it flows through the ventilator
54 and is supplied, as supply-air stream ZU to the room
which is to be air-conditioned. At the same time, the
ventilator 54' removes waste air AB from the room which
is to be air-conditioned, said waste air passing
through the air filter 46' into the end chamber 40'.
The third flap systems 68, 68', which are open, allow
the waste-air stream to pass into the two third
connection chambers 70, 70' from where, deflected by
the second flow channel system 16 of the heat-recovery
units 10 and 12 and in the intercepting and deflecting
basin 18, it passes into the fourth connection chambers
CA 02260228 1998-12-30
- 10 -
72, 72'. From here, the air stream flows, as expulsion
air FO, through the fourth flap systems 74, 74' into
the end chamber 38' and, from there, into the
surroundings.
If the ambient temperature is lower than the
temperature of the room whlch ls to be alr-condltloned,
in the heat-recovery units 10 and 12, whlch then act as
a heat exchanger, heat ls removed from the waste-
alr/expulslon-air stream 58 and transferred to the
outside-air/supply-air stream 56, as a result of which
the latter is heated up. If, on the other hand, the
outslde temperature is hlgher than the desired
temperature in the room which is to be alr-condltioned,
heat is transferred from the outslde-alr/supply-alr
stream 56 to the waste-alr/expulslon-alr stream 58,
which results in the supply alr ZU belng cooled. At the
same time, it is possible to cool the waste-
air/expulsion-air stream adiabatically and the heat-
recovery units 10, 12 by spraying them with water by
means of the nozzle bars 86, as a result of whlch the
outslde-alr/supply-alr stream 56 ls cooled lndirectly.
For temperature regulation in the room whlch ls
to be alr-condltloned, lt ls posslble to regulate the
bypass flap systems 84, 84'. As a result, part of the
waste-alr/expulsion-alr stream is routed past the heat-
recovery units 10, 12.
It is also conceivable to open the further flap
systems 80, 80', as required, in order to supply part
of the waste-air/expulsion-alr stream 58, before lt
flows through the heat-recovery unlts 10, 12, to the
outslde-alr/supply-alr stream 56 and to dlrect it,
mlxed wlth the latter stream 56, to the room whlch ls
to be alr-condltloned.
The routlng of the outside-alr/supply-alr
stream 56 and waste-alr/expulslon-alr stream 58 ln
regeneratlve operatlon is shown in Figures 5 to 7. In a
first operatlng phase, during a speclflc perlod of
tlme, the outslde-alr/supply-alr stream 56 ls routed
just through one heat-recovery unlt 10 or 12, whereas,
CA 02260228 1998-12-30
at the same time, the waste-air/expulsion-air stream 58
is routed just through the other heat-recovery unit 12
or 10, respectively. In a following, second operation
phase, during a specific period of time, the two
streams 56, 58 are then routed through the respectively
other heat-recovery unit 10 or 12. This periodic
alternation takes place at a frequency of approximately
30 to approximately 60 seconds.
Figures 5 to 7 show that operating phase in
which the outside-air/supply-air stream 56 is routed
through the heat-recovery unit 12 and the waste-
air/expulsion-air stream 58 is routed through the heat-
recovery unit 10. As can be gathered from Figures 6 and
7, the second flap system 66', which is assigned to the
heat-recovery unit 12, and the further flap systems 78'
and 80', which are likewise assigned to said heat-
recovery unit 12, are located in the open position,
whereas the third, fourth and bypass flap systems 68',
74' and 84', which are assigned to said heat-exchange
unit 12, are located in the closed position. If
ventilator 54 is in operation, the corresponding first
flap system 60' is automatically in the open position,
and the outside air AU taken in by the air filter 46
passes from the end chamber 38 into the first
connection chamber 62'. From here, part of the fluid
stream flows through the first flow channel system 14,
while the rest of the fluid stream passes through the
further flap system 78' into the fourth connection
chamber 72' and, from here, flows through the second
flow channel system 16. The latter part of the fluid
stream passes into the third connection chamber 70'
and, from this, passes through the open flap system 80'
into the second connection chamber 64', where the two
part-streams combine and pass through the second flap
system 66 into the end chamber 40, from where they are
supplied by means of the ventilator 54, as supply-air
stream ZU, to the room which is to be air-conditioned.
As a result of the negative pressure in the fourth
connection chamber 72' in relation to the pressure in
CA 02260228 1998-12-30
the end chamber 38', the fourth flap system 74' is
closed automatically.
At the same time, as is shown in Figures 5 and
7, the waste-air/expulsion-air stream 58 is routed just
through the heat-recovery unit 10. For this purpose,
the first and second flap systems 60, 66, which are
assigned to the heat-recovery unit 10, are closed and
the third and fourth flap systems 68, 74 and the
corresponding further flap systems 78, 80 are open. The
waste air AB taken in by the ventilator 54' and passing
through the air filter 46' into the end chamber 40'
passes, from here, into the third connection chamber
70, where the fluid stream divides up. Part of the
fluid stream flows through the second flow channel
system 16 in the form of a U and passes directly into
the fourth connection chamber 72, whereas the rest of
the fluid stream passes through the further flap system
80 into the third connection chamber 70 and, from here,
flows through the first flow channel system 14. The
latter part of the fluid stream then passes from the
first connection chamber 62 through the further flap
system 78, which is open, likewise into the fourth
connection chamber 72, where the two part-streams
combine to form an expulsion-air stream FO, which
passes through the automatically opened, fourth flap
system 74 into the end chamber 38' and, from the
latter, into the surroundings. Since the pressure in
the first connection chamber 62 is higher than in the
end chamber 38, the first flap system 60 is closed
automatically.
Following completion of one operating phase,
the flap systems assigned to one heat-recovery unit 10
are displaced into that position which, in the previous
operating phase, was assumed by the flap systems
assigned to the other heat-recovery unit 12, and vice
versa. This results in the situation where, during one
operating phase, the warmer air stream, be this the
outside-air/supply-air stream 56 or waste-
air/expulsion-air stream 58, heats up the corresponding
CA 02260228 1998-12-30
heat-recovery unit 10 or 12, which then acts as a heat
accumulator, while the other air stream removes heat
from the previously heated-up heat-recovery unit 12 or
10, respectively.
Since the air-conditioning installation is
operated with regenerative action in particular in the
case of extreme outside temperatures, it is possible,
if necessary and if a built-in heating and cooling
assembly 90, 92 is provided, either additionally to
withdraw heat from the waste-air/expulsion-air stream
58 and supply said heat to the outside-air/supply-air
stream 56, for additional heating, or to use the
additional heating and cooling assembly 90, 92 to
withdraw heat from the outside-air/supply-air stream
56, in order to cool the latter, and supply said heat
to the waste-air/expulsion-air stream.
It should also be mentioned in conjunction with
regenerative operation that it is possible, by means of
control of the bypass flap systems 84, 84', for part of
the outside-air/supply-air stream 56 and/or of the
waste-air/expulsion-air stream 58 to be directed past
the corresponding heat-recovery unit 10, 12. This
permits extremely efficient regulation.
Of course, it is conceivable for the heat-
recovery units and the flap systems and ventilators tobe arranged differently from the arrangement shown in
the figures. It is, of course, also conceivable for
each heat-recovery unit to have just a single plate
heat exchanger, or more than two plate heat exchangers,
or heat exchangers which are constructed differently
and are also suitable for heat accumulation.
For the sake of completeness, it should also be
mentioned that the end chambers 38, 38', 40, 40' are
not essential. It is conceivable for pipelines to be
routed directly to the transverse walls 22, 24, and
thus for the transverse walls to form the end walls of
the air-conditioning installation.
It is also conceivable to allow the air
streams, in recuperative operation, to flow just
CA 02260228 l998-l2-30
- 14 -
through one of the two heat-recovery units. In this
case, however, greater flow speeds and a higher flow
resistance have to be accepted. The same applies if, in
regenerative operation, the air streams were to be
routed through in each case one of the flow channel
systems.
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