Field of the Invention
[0001] The present invention generally relates to cooling systems, and in particular a fluid
cooling heat exchanger in which fluid is cooled substantially by convective heat transfer.
The invention is particularly suited to cooling systems for relatively large volumes
such as; for example, a part of an air conditioning system in large office buildings
or commercial refrigeration systems.
Background of the Invention
[0002] Heating and cooling systems are used in most modern premises to maintain the temperature
in those premises within predetermined limits. One type of system for the cooling
of large buildings is a cooling system that incorporates a roof top mounted heat exchanger.
In this type of system, the thermal energy from air in the building is transferred
through one or more interconnected heat exchange units within the building to a roof
mounted heat exchange unit. In the building, a refrigerant is used to cool air as
the air passes through a heat exchange unit (an evaporator). The heated refrigerant
is then passed to another heat exchange unit (a condenser) wherein heat is extracted
from the refrigerant using a heat exchange fluid such as water. The heated water is
usually then transferred to the roof top mounted heat exchanger which uses ambient
air at the roof of the building to cool the water in preparation for further use.
The most commonly installed roof top mounted heat exchanger is a type known as an
"open" system that incorporates many disadvantages, such as the propensity to generate
and transmit sufficient levels of the bacterium known as
legionella pneumophilia to cause Legionnaire's disease in people that inhale the bacterium.
[0003] Large buildings typically require the removal of a large heat load particularly during
the height of summer. Accordingly, roof top mounted heat exchangers are generally
configured to provide a sufficient heat exchange capacity to cope with the largest
expected heat load.
[0004] In view of the problems associated with "open" roof top mounted heat exchangers,
there is an increasing trend for building owners to consider "closed" roof top mounted
heat exchangers or heat exchanger arrangements wherein the cooling fluid remains within
a closed circuit and is not exposed to the atmosphere. A closed circuit heat exchanger
avoids the problems associated with generating and transmitting the legionella pneumophilia
bacterium. However, closed circuit heat exchangers suffer a range of different problems
including a substantially reduced heat exchange capacity as compared with an open
roof top mounted heat exchanger of similar dimension and weight.
[0005] Closed circuit heat exchangers typically use large planar tube and fin modules that
include fluid carrying passages with fan arrangements to pass air through and/or over
the planar modules to meet the desired heat exchange requirement. Construction of
these types of heat exchangers necessitate specialised equipment to move, mount and
assemble the structure. Further, specialised structural support members are generally
required on a building roof to distribute the weight of a closed circuit heat exchanger
across the roof surface and a significant amount of space on the roof of the building
is required to accommodate the relatively large size. Typically, closed circuit heat
exchangers are constructed "off site", transported to the installation site on a large
truck and lifted by crane from the truck to the rooftop for installation and commissioning.
The cost and inconvenience of arranging transport and cranes is significant and increases
the cost of the overall installation.
[0006] Closed circuit heat exchangers may also include microchannel heat exchangers and
US Application Number 2006/0130517 discloses a unit cooler including a housing adapted to be positioned within a refrigerated
environment and at least one microchannel evaporator coil supported by the housing.
US Application Number 2006/0130517 describes that prior to the invention disclosed therein, microchannel evaporator
coils had not been used in large-scale refrigeration systems due to the high cost
and difficulty associated with manufacturing a microchannel evaporator coil of sufficient
size to accommodate the required refrigeration capacity of a large-scale refrigeration
system.
[0007] In the instance of installing a large closed circuit heat exchanger, it is sometimes
necessary to situate a large crane on a street next to the building to lift the tower
to the building roof top. This may require the street to be closed during the installation
which generally restricts installation to periods of time of relatively low street
usage. Of course, this generally relates to night times or weekends which increase
the rate of pay for any installation staff and hence increases the overall cost of
installation.
[0008] Accordingly, it is desirable to provide an alternative closed circuit heat exchanger
that is more compact than existing arrangements and avoids, or at least ameliorates,
the cost and difficulty associated with transporting, installing and supporting a
closed circuit heat exchange system.
Summary of the Invention
[0009] In one aspect, the present invention provides a modular heat exchange system comprising
at least two heat exchange units each having at least one first heat exchanger having
a closed circuit for cooling the fluid therein, at least one air cooler located upstream
of the at least one first heat exchangers located in each of the at least two heat
exchange units, at least one first fan arrangement operable to cause air to pass through
the at least one air coolers and the at least one first heat exchangers, characterised
in that the at least one air coolers include moisture absorbent material, and the
at least one first heat exchangers of each of the at least two heat exchange units
are micro-channel heat exchangers in fluid communication allowing flow of cooling
fluid therebetween.
[0010] In one embodiment, the air cooler, when in use, has air passing through it caused
by a fan arrangement, which may be the first fan arrangement. In this embodiment the
air that passes through the air cooler is cooled. The cooled air then passes through
and/or over the closed circuit heat exchanger.
[0011] In another embodiment, the first closed circuit heat exchanger is configured in a
substantially cross sectional tubular arrangement wherein the first fan arrangement
is operable to cause air to pass longitudinally through the internal space of the
substantially tubular arrangement of the first closed circuit heat exchanger. Of course,
air may also pass through the walls of the substantial tubular arrangement thereby
assisting the heat exchange process.
[0012] In a further embodiment, a second heat exchanger having a closed circuit for cooling
fluid is arranged with the first closed circuit heat exchanger such that they form
a substantially cross sectional tubular arrangement with an internal space through
which air can pass.
[0013] The fan arrangement can be situated in various locations relative to the first closed
circuit heat exchanger. However, in one exemplary embodiment, the direction of the
air flow resulting from the operation of the first fan arrangement is in a direction
that is substantially aligned with the longitudinal axis of the tubular arrangement,
or is substantially aligned with the longitudinal axis of the arrangement of the first
and the second closed circuit heat exchangers.
[0014] Of course, a modular heat exchange system according to the present invention may
include one or more fan arrangements that cause air to pass through the first heat
exchanger. In those embodiments including two or more fan arrangements, the direction
of air flow of each fan arrangement may be substantially aligned. In exemplary embodiments
of the present invention, the modular heat exchange system includes a single fan arrangement
at one end of the tubular arrangement for forcing air through the first closed circuit
heat exchanger.
[0015] When the first closed circuit heat exchanger is formed in a substantially tubular
arrangement, it may have various cross-sectional shapes perpendicular to its nominal
longitudinal axis. Suitable shapes include substantially square, hexagonal, octagonal,
star-shaped, triangular or similar. In one embodiment, the tubular arrangement has
a generally circular or oval cross-section perpendicular to its nominal longitudinal
axis. In another exemplary embodiment, the substantially tubular arrangement has a
generally square or rectangular cross-section perpendicular to the longitudinal axis.
In this embodiment, the generally square or rectangular cross-section has one or more
arcuate corners.
[0016] The structure of the tubular arrangement can circumferentially extend wholly or partially
around the longitudinal axis of the tubular arrangement. Of course, in some arrangements
the tubular arrangement forms a continuous body around the longitudinal axis. This
forms an enclosed tube around the longitudinal axis of the tubular arrangement. In
other exemplary embodiments, the first closed circuit heat exchanger could operate
with the substantially tubular arrangement and a heat exchange body forming the wall
of the tubular arrangement extending partially around its longitudinal axis. This
would provide a circumferential gap in the body of the tubular arrangement. As can
be appreciated, the greater the tubular arrangement of the heat exchange body extends
around the longitudinal axis, the more efficiently the configuration utilises the
air flow from the fan arrangement for cooling the cooling fluid contained in the fluid
passages in the walls of the tubular arrangement. It is therefore preferable that
the tubular arrangement of the heat exchange body extends around its longitudinal
axis to the greatest extent possible to substantially form an enclosure around the
longitudinal axis. Of course, two or more separate closed circuit heat exchangers
could be substantially butted together, or situated in close proximity, to form a
generally tubular enclosure through which air passes.
[0017] The inclusion of a gap in the circumference of the tubular arrangement could occur
for numerous reasons. In one embodiment, a gap is provided for the provision of a
header arrangement through which cooling fluid enters and exits the closed circuit
forming the walls of the tubular arrangement. The header may be provided at one or
both of two spaced apart longitudinal ends each of which extend generally parallel
to the longitudinal axis of the tubular arrangement. The closed circuits for the cooling
fluid circumferentially extend between these ends. In some arrangements, only one
of the longitudinal ends includes a header, the other end having connecting sections
having a closed end. In other arrangements, each of the longitudinal ends includes
a header thereby allowing fluid to flow between the headers or in separate sections
of the heat exchange body connected to the respective headers.
[0018] In one exemplary embodiment, cooling fluid flows through the first closed circuit
heat exchanger by entering the header arrangement at the top end of the first closed
circuit heat exchanger and exiting the header arrangement at the base end of the first
closed circuit heat exchanger. In this embodiment, the fan arrangement is preferably
configured to cause air to flow first from the bottom and through the substantially
enclosed space within the tubular heat exchanger unit oriented vertically with the
air being caused to flow axially upwardly to exit from the top end of the first closed
circuit heat exchanger. In another exemplary embodiment a fan arrangement is located
proximate to, or at the top of, the first closed circuit heat exchanger. Either of
these embodiments provides a counter current heat exchange arrangement where the air
flow and cooling fluid flow are in different directions.
[0019] A large variety of types of fluid carrying passages for the first closed circuit
heat exchanger could be used including plate, plate-fin, spiral, tube, double pipe,
coil or similar. In one exemplary embodiment, the heat exchanger includes a closed
circuit formed by a plurality of circumferentially arranged passages that are generally
laterally arranged in the heat exchange body relative to the longitudinal axis.
[0020] The cooling fluid used in the first closed circuit heat exchanger can vary depending
on the particular cooling requirements. In some applications, the cooling fluid is
water or oil. In other applications, the cooling fluid is selected from a refrigerant
gas such as ammonia, Freon or carbon dioxide.
[0021] In yet another embodiment, the first closed circuit heat exchanger is a microchannel
heat exchanger with fluid passages that are substantially smaller than those of standard
tube and fin closed circuit heat exchangers. In one exemplary arrangement having a
closed circuit microchannel heat exchanger, the cooling fluid is supplied through
a substantially horizontal supply header and is passed from the closed circuit microchannel
heat exchanger through another substantially horizontal return header. In one arrangement
the supply header is located at or near the top of the closed circuit microchannel
heat exchanger and the return header is located at or near the bottom of the closed
circuit microchannel heat exchanger such that cooling fluid passes into the closed
circuit microchannel heat exchanger at or near the top and passes once through the
closed circuit microchannel heat exchanger by the action of gravity and subsequently
passing out through the return header, at or near the bottom.
[0022] In another embodiment the supply header and the return header are located at or near
the vertical sides of the closed circuit microchannel heat exchanger. Typically, cooling
fluid flows in through the supply header and passes through the fluid passages of
the closed circuit microchannel heat exchanger to the return header where the cooling
fluid may flow out of the return header.
[0023] In a further exemplary embodiment, a closed circuit microchannel heat exchanger includes
a first and second closed circuit microchannel heat exchange modules arranged such
that the surfaces of the first module are substantially parallel to the surfaces of
the second modules and aligned such that the flow of cooled air passes through the
first module and subsequently through the second module. In this embodiment cooling
fluid is arranged to flow through the first module and subsequently through the second
module.
[0024] It should be noted that the at least one first heat exchanger of the present invention
has a closed circuit for the cooling fluid to ensure that the cooling fluid is prevented
from exposure to the atmosphere, and in particular, to the air passing through the
cooling fluid heat exchanger. In instances where water is used as the cooling fluid,
this separation of cooling fluid as it passes through the heat exchanger (referred
to as a "closed circuit" heat exchanger) from the air passing through the heat exchanger
removes the risk of the distribution of airborne legionella bacterium. In practice,
the closed circuit is likely to form part of a loop within a cooling system where
the cooling fluid is transported from a location where the fluid is used to absorb
thermal energy and subsequently transported to the cooling fluid heat exchanger in
order to remove the absorbed thermal energy from the cooling fluid.
[0025] In some environments where the ambient external temperature can exceed 30° Celsius,
the use of a closed circuit heat exchanger system cooled with ambient air is unable
to remove sufficient thermal energy for the air conditioning system to form a commercially
viable configuration. In these arrangements, convective cooling is therefore only
possible by providing an impractically large primary heat exchanger which is usually,
a commercially non-viable prospect.
[0026] In high ambient temperature environments, cooling the ambient air prior to passing
same through a heat exchanger results in a commercially viable configuration.
[0027] In order to cool air flowing through the first heat exchanger, the air cooler may
be located over or proximate to one or more air inlets through which the fan arrangement
causes cooled air to pass through the first closed circuit heat exchanger. In one
embodiment, the fan arrangement draws cooled air through the walls of the first closed
circuit heat exchanger. In this embodiment, at least one air cooler is arranged radially
outwardly of the walls of the first closed circuit heat exchanger.
[0028] The air cooler may have a number of arrangements. In one exemplary embodiment, the
air cooler includes a moisture absorbent material in the form of moisture absorbent
pads, that are, in use, maintained moist such that air passing through the cooler
is cooled by the action of evaporation prior to passing over a portion of the closed
circuit in the first heat exchanger. It has been found that the use of an air cooler
with moisture absorbent material significantly improves the cooling capacity of the
heat exchange unit. Accordingly, the same cooling capacity can be produced from a
substantially smaller heat exchange unit, as compared with a heat exchange unit without
an air cooler, thereby reducing the capital cost of the heat exchange unit for a particular
thermal load.
[0029] In one embodiment, the moisture absorbent material includes a plurality of fluted
apertures and is arranged generally parallel to one or more of the walls of the body
of the first closed circuit heat exchanger. In this arrangement, the air cooler may
include a fluid dispenser that dispenses moisture onto the moisture absorbent material
thus maintaining it moist during operation of the heat exchange unit.
[0030] In another embodiment, the heat exchange unit includes a moisture recirculation system
for evaporatively cooling air, the system including a moisture distribution arrangement
which, in use, distributes moisture to an upper portion of the moisture absorbent
material in the air cooler; a trough disposed below the lower most portion of the
moisture absorbent material in the air cooler for initially collecting moisture run-off;
a sump in fluid communication with the trough for collecting and storing said run-off;
and a pump in fluid communication with the sump which, in use, transfers moisture
from the sump to the moisture absorbent material.
[0031] In an embodiment, the moisture absorbent material supports an adiabatic process when
it is maintained moist with water. Although water is inexpensive and generally in
plentiful supply, in recent times the need to conserve water as much as possible has
become well known particularly in view of water restrictions that have been imposed
in many parts of the world that are experiencing extended drought conditions. Of course,
the water may include additives such as anti-microbial agents and/or any other additives
to improve the operation of the water recirculation system.
[0032] In another embodiment, the trough disposed below the lower most portion of the moisture
absorbent material is dimensioned such that per unit length the trough will collect
and/or hold substantially less run-off as compared with existing trough arrangements
that act as the run-off collection and storage means. The trough may act as a temporary
and intermediate storage location for run-off water until such time that the water
collected in the trough can be transferred to the sump. As the sump is not required
to extend the full length of the moisture absorbent material, it may be substantially
smaller and hold substantially less water as compared with existing trough arrangements
whilst still maintaining a positive head of pressure at the pump intake.
[0033] In this particular embodiment, a reduced sump size (as compared with usual arrangements)
assists in reducing the operational weight of the heat exchange unit which is a factor
requiring consideration with respect to providing adequate structural support for
the heat exchange unit.
[0034] In an embodiment of the invention, an external source of make-up water (to replace
water that is evaporated during the air cooling process) is in fluid communication
with the moisture recirculation system. In this embodiment, the supply of make-up
water is controlled by a valve which is activated and deactivated in accordance with
a control system that determines the requirement for make-up water. The make-up water
may be supplied to the sump. Alternatively, and preferably, the make-up water is supplied
directly to the moisture absorbent material and as run-off water is collected and
passed to the sump, the level of stored water in the sump increases.
[0035] In one embodiment, the pump transfers moisture from the sump to the moisture absorbent
material by pumping moisture from the sump to the moisture distribution arrangement.
[0036] In this latter embodiment, when water is used as the moisture, a standard float valve
arrangement is used to monitor the water level in the sump thus ensuring that a positive
head of pressure is maintained at the pump intake. The external water is not supplied
to the sump but rather is applied directly to the moisture absorbent material of the
air cooler and may be transferred through the water distribution arrangement that
distributes water to the upper portions of the moisture absorbent material. As a result
of by-passing the sump, the make-up water is directly deposited where it is needed
without the normal delay associated with filling the sump and then transferring the
make-up water from the sump, through the pump and subsequently to the water distribution
arrangement. Of course, the time required to increase the water level in a relatively
small sump is substantially less as compared with existing trough arrangements. However,
applying external make-up water directly to the moisture absorbent material reduces
the time required to saturate the moisture absorbent material.
[0037] Of course, opening the float valve which allows the ingress of external (make-up)
water into the water recirculation system ultimately increases the sump contents as
water runs off the moisture absorbent material which in turn fills the sump and eventually
acts to close the float operated valve.
[0038] Of course, this supply of external water by the valve to the moisture absorbent material
may occur through a separate water distribution system as compared with the water
distribution system that is in fluid communication with the sump and pump arrangement.
However, there is no reason why the same water distribution arrangement could not
be used for both recirculated water and external make-up water and in an embodiment
of the invention, the make-up water is introduced into the water conduit that extends
from the pump outlet to the water distribution system disposed above the moisture
absorbent material.
[0039] Embodiments of the invention that incorporate intermediate and temporary run-off
water collection arrangements with any collected run-off water being directed to a
sump for subsequent transfer by pump to a water distribution arrangement disposed
above the moisture absorbent material may substantially reduce the amount of wasted
water particularly where the dimensions of the sump and trough are substantially reduced
as compared with existing trough arrangements. In particular, by using a trough as
an intermediate run-off water collection arrangement below the moisture absorbent
material and subsequently transferring run-off water to a sump, the sump may be dimensioned
significantly smaller than standard trough arrangements whilst still maintaining the
necessary head of pressure at the pump intake.
[0040] Of course, where it is possible to operate a water recirculation system with a smaller
sized sump, in addition to the reduced operational weight of the system, the amount
of wasted water is commensurately reduced as the regular dumping cycle will only result
in the dumping of a smaller quantity of water.
[0041] In an embodiment of the invention that directs make-up water to a point in the water
recirculation system subsequent to the outlet of the pump and prior to the inlet of
the water distribution arrangement, the amount of time required to saturate the moisture
absorbent material from a dry condition is reduced as compared with an arrangement
where the make-up water is directed into a sump or trough in the first instance and
subsequently pumped to the water distribution arrangement. Therefore, where make-up
water is directed to a point between the outlet of the pump and the inlet of the water
distribution arrangement, the time required to transition a cooling apparatus from
dry mode tu wet mode is substantially reduced as compared with existing systems. Where
this delay is sufficiently reduced, the requirement to pre-emptively commence operation
of the water recirculation system in anticipation of worsening climatic conditions
is obviated. A more responsive water recirculation system that can transfer from dry
to wet mode as quickly as possible has the associated benefit of avoiding more instances
of false priming of the air cooling system and hence avoiding the wastage of water
in those instances where a false priming would otherwise occur.
[0042] According to a further aspect, the present: invention provides a method of circulating
moisture for evaporatively cooling air in the moisture recirculation system, the method
including the steps of applying the moisture to the upper portion of the moisture
absorbent material, initially collecting the moisture run-off in the trough disposed
below the moisture absorbent material, transferring the run-off moisture from the
trough to the sump for storage, transferring the moisture from the sump to the moisture
absorbent material, and monitoring the moisture level in the sump and in the event
that the moisture level in the sump falls below a predetermined threshold, activating
supply from an external source of make-up moisture and supplying said make-up moisture
directly to the moisture absorbent material.
[0043] According to another aspect of the present invention, there is provided a modular
heat exchange system including at least two heat exchange units each having a first
heat exchanger having a closed circuit for cooling fluid, at least one air cooler
forming a second heat exchanger located upstream of the first heat exchanger, and
at least one first fan arrangement operable to cause air to pass through the at least
one air cooler and the first heat exchanger, wherein the first heat exchangers of
each of the at least two heat exchanger units are micro-channel heat exchangers and
in fluid communication allowing flow of cooling fluid therebetween.
[0044] In some embodiments, from a cooling fluid flow perspective, the first heat exchanger
is arranged in parallel or in series with one or more further first heat exchangers.
In this exemplary embodiment, each of the first closed circuit heat exchangers effectively
forms a heat exchange unit and one, or a small number, of heat exchange units can
be designed and constructed. Each heat exchange unit will have a predetermined heat
exchange capacity. One or more heat exchange units can therefore be used in a modular
heat exchange system to accommodate the heat loading for a selected application or
use. For example, when used in a cooling system for a building, a number of heat exchange
units could be selected to accommodate the maximum heat loading from the building
during the maximum temperature period during summer, based upon the heat exchange
capacity of each unit.
[0045] In another embodiment, the heat exchange unit includes a second heat exchanger aligned
substantially in series with the first heat exchanger from an air flow perspective
thereby forming a heat exchanger stack. In this embodiment, an increased heat exchange
capacity is achieved by use of a stack of heat exchangers although placing two or
more heat exchangers in air flow series to form a stack is expected to increase the
resistance of air flow through the stack and hence require a substantially greater
supply of air. This in turn increases the electrical energy consumption of the fan
arrangement as it is required to cause air to pass through an arrangement presenting
greater air flow resistance as compared with a single heat exchanger.
[0046] In yet another aspect, the present invention provides a method of installation of
a modular heat exchange system including transporting one or more heat exchange units
to an installation location, connecting the one or more heat exchange units to a cooling
fluid supply, connecting the one or more heat exchange units to a power supply, and
activating the modular heat exchange system.
[0047] Typically, a heat exchange unit would be relatively small in size as compared with
roof top mounted heat exchangers using planar tube and fin heat exchangers. In one
embodiment, heat exchange units are sized to fit into the goods lift of a building.
In this way, each individual heat exchange unit could be transported to the roof of
the building via the goods lift and thereafter the modular heat exchange system could
be assembled on the rooftop by connecting each of the individual heat exchange units.
In this respect, each heat exchange unit would be connected during installation to
provide the overall required heat exchange capacity for that building.
[0048] Maintenance of such a modular system is more flexible than existing systems as any
faulty heat exchange unit could be isolated and replaced without de-commissioning
the remaining heat exchange units. Isolating a faulty unit and replacing or repairing
the damaged heat exchange unit whilst the remaining heat exchange units continue to
function provides a significant benefit with respect to the convenience with which
repairs to a heat exchange system may be effected.
[0049] Roof top mounted heat exchangers are generally custom constructed to meet the heat
demand of a particular building. Accordingly, each component part such as the first
heat exchanger, fan arrangement or the like can in some instances be custom fabricated
for that particular building. As will be appreciated, this can lead to very large
structures being constructed on building rooftops. The present invention can in some
embodiments be custom constructed.
Brief Description of the Drawings
[0050] The present invention will now be described with reference to the figures of the
accompanying drawings, which illustrate exemplary embodiments of the present invention,
wherein:
Fig. 1 is schematic diagram illustrating the main components of a closed circuit cooling
system incorporating an air-cooled roof top mounted heat exchanger.
Fig. 2 is a schematic diagram illustrating a further form of a closed circuit cooling
system incorporating an air-cooled roof top mounted heat exchanger having air cooler
including moisture absorbing pads.
Fig. 3 is a plan view of a closed circuit heat exchanger coil according to one exemplary
embodiment of the present invention.
Fig. 4 is a front elevation view of the closed circuit heat exchanger coil of Fig.
2.
Fig. 5 is a right side elevation view of the closed circuit heat exchanger coil of
Fig, 2.
Fig. 6 is a perspective view of a header arrangement and coil ends of the closed circuit
heat exchanger coil of Fig. 2.
Fig. 7 is a front elevation view of a first exemplary embodiment of a heat exchange
unit according to the present invention.
Fig. 8 is a front elevation view of a second exemplary embodiment of a heat exchange
unit according to the present invention.
Fig. 9 is plan view of a single heat exchange unit of a modular heat exchange system
according to an exemplary embodiment of the present invention.
Fig. 10 is plan view of a modular heat exchange system having two heat exchange units
according to an exemplary embodiment of the present invention.
Fig. 11 is plan view of a modular heat exchange system having three heat exchange
units according to another exemplary embodiment of the present invention.
Fig. 12 is plan view of a modular heat exchange system having four heat exchange units
according to a further exemplary embodiment of the present invention.
Fig. 13 is a plan view of a heat exchange unit according to one exemplary embodiment.
Fig. 14 is a plan view of a heat exchange unit according to another exemplary embodiment
shown without air coolers.
Fig. 15 is a front elevation view of an embodiment, of the heat exchange unit with
a duplex heat exchanger arrangement.
Fig. 16 is a view of the heat exchange unit according to Fig. 13 shown with a different
orientation.
Fig. 17 is a view of the heat exchange unit according to Fig. 14 shown with a different
orientation.
Fig. 18 is a front elevation view of an embodiment of the heat exchange unit.
Fig. 19 is a view of an embodiment of a closed circuit heat exchanger showing a planar
side of the heat exchanger body.
Fig. 20 is a side view of the closed circuit heat exchanger of Fig. 19.
Fig. 21 is a top view of a modular heat exchange system with eight heat exchange units.
Fig. 22 is a diagrammatic representation of an embodiment, of a heat exchange unit
incorporating an existing moisture recirculation system;
Fig. 23 is a diagrammatic representation of an embodiment of a cooling system including
a moisture recirculation arrangement according to an embodiment of the invention;
and
Fig. 24 is a diagrammatic representation of the cooling system of Fig. 23 providing
a perspective view of some of the components detailed in Fig. 23.
Detailed Description
[0051] Referring to Fig. 1, there is shown a schematic diagram of a conventional closed
circuit cooling system arrangement (18) which provides cooled air to a building (20).
This closed circuit cooling system arrangement (18) includes a rooftop mounted heat
exchanger (23) which typically includes substantially planar primary heat exchange
plates (27, 27A).
[0052] The illustrated closed circuit cooling system arrangement (18) comprises a heat exchanger
system (21) located at the base of the building (20). designed for exchanging thermal
load between an enclosed loop of refrigerant fluid (22) and a water circuit (30).
The water circuit (30) is linked to the internal air conditioning system of the building
(not shown). Air in the building (20) is generally cooled by drawing air through a
duct in which a portion of the chilled water circuit (30) resides. Thermal energy
from the air is transferred to the chilled water circuit (30) cooling the air in the
building (20). The enclosed loop of refrigerant fluid (22) is used to cool the water
circuit (30). This is achieved by passing the refrigerant fluid through a heat exchanger
(28) where it absorbs thermal energy from the water circuit (30) which is also moving
through the heat exchanger (28) in a counter-current flow, The flow of refrigerant
fluid through the circuit (22) is driven by a compressor (24) and regulated by expansion
valve (26).
[0053] A roof top mounted heat exchanger (23) is situated on the roof of the building (20).
The illustrated roof top mounted heat exchanger (23) consists of air cooled condensers
(27, 27A), which are configured with electrically driven fans (29 and 31) located
at the top of the condensers (27, 27A), which draws air through the condenser coils
of (27, 27A) via side air inlets (not illustrated) and expelling the drawn air through
the fans (29 and 31) and out above the roof top mounted heat exchanger (23). It is
usual for roof top mounted, heat exchanger (23) to be placed upon the roof of a building
(10) as heat exchangers are usually large and due to the use of large fans, (29, 31)
emit a substantial amount of noise during operation. The refrigerant fluid is pumped
from the basement of the building (20) up to the rooftop of the building (20) and
passed through the condenser coils, (27, 27A) where heat is transferred from the refrigerant
fluid to the air drawn through the coils, (27, 27A) by the fans (29 and 31).
[0054] The illustrated air cooled condenser uses induced draught counter-flow to draw air
through the tower (23). In this configuration, the fans ((29), 30) are located at
the air outlet of the condensers (27, 27A). Air enters the tower (23) and is drawn
vertically through the condenser (27) in a direction opposite to the flow of cooling
fluid through the condensers (27, 27A).
[0055] Referring now to Fig. 2 there is shown a second form of closed circuit cooling system
arrangement (32) which provides air conditioned air to a building (34). This cooling
system arrangement (32) can include a roof top mounted heat exchanger (35) with a
closed circuit cooling arrangement.
[0056] The illustrated cooling system arrangement (32) is similar to that described in relation
to Fig. 1, in that it includes an enclosed circuit of refrigerant fluid (36) that
is passed through a condenser (38) and an evaporator (40) by a compressor (42). The
flow of fluid through the enclosed circuit (36) is controlled by an expansion valve
(44). The evaporator (40) includes an enclosed water circuit (46) which has thermal
energy removed therefrom in order for the enclosed water circuit (46) to be used to
effect cooling of the air in the building (34) in a similar manner as described previously.
The condenser (38) operates as a heat exchanger to extract thermal energy from the
closed loop of refrigerant fluid (36).
[0057] The removal of thermal energy from the enclosed loop of refrigerant fluid (36) in
the condenser (38) is effected by the use of cooling fluid which is drawn into the
condenser (38) through tubing (50) and carried out of the condenser (38) through tubing
(48). Cooling fluid is drawn into the condenser (38) and passed through it under the
control of pump (51). Cooling fluid emitted from the condenser (38) is carried by
tubing (48) to the rooftop of the building (34) where it enters a rooftop mounted
closed circuit heat exchanger (52) of the closed circuit roof top mounted heat exchanger
(35). The closed circuit roof top mounted heat exchanger (35) includes electrically
driven fans (54 and 56) that operate to draw air therethrough.
[0058] The tubing (not illustrated in any detail in Figs. 1 and 2) of the closed circuit
heat exchanger (52) is generally thermally conductive and formed in a tortuous path
disposed in a region that will be subject to air flow as air is drawn through the
closed circuit heat exchanger (52). As can be appreciated, sections of the tubing
can include thermally conductive extensions to improve the convective heat transfer
efficiency as air passes over the tubing. Usually, thermally conductive extensions
comprise heat fins that are usually formed from a suitably thermally conductive material.
Having passed through the portion of tubing formed in a tortuous path, the water is
then carried out of the rooftop mounted closed circuit heat exchanger (52) through
down pipe (50) and is pumped into the condenser (38) using the pump (51).
[0059] In addition to passing cooling fluid through a portion of tubing subject to forced
airflow, the roof top mounted heat exchanger (35) also includes an air cooler (57).
The air cooler (57) includes moistened water absorbent material located upstream of
the air inlets of the closed circuit heat exchanger (52). Operation of the fans (54,
56) draws air through the moistened water absorbent material of the air cooler (57)
causing moisture in the water absorbent material to evaporate. The energy required
to evaporate the moisture is extracted from the air, thus cooling the air prior to
passing same through the closed circuit heat exchanger (52). The resulting cooler
air allows for a greater temperature change when passing through the closed circuit
heat exchangers (52) and therefore increases the effectiveness of roof top mounted
heat exchanger (35) in removing thermal energy from the water flowing through the
closed circuit heat exchanger (52).
[0060] Figs, 3 to 6 show one exemplary form of a first closed circuit heat exchanger (60)
of a heat exchange unit which can be used in closed circuit roof top mounted heat
exchangers (23). As illustrated, the closed circuit heat exchanger (60), in this embodiment,
is configured in a generally tubular shaped coil with a nominal longitudinal axis
(62) X-X (best shown in Figs. 4 and 5). The tubular coil (62) is configured with a
generally square lateral cross-sectional area (i.e. perpendicular to the axis X-X)
as best shown in Fig. 3. The square lateral cross-section has rounded corners. The
tubular coil (62) does not extend completely around the longitudinal axis X-X, but
rather has a longitudinal gap (64) at one corner thereof At the longitudinal gap (64)
there is positioned a longitudinally arranged header arrangement (66) (best seen in
Fig. 6) which includes inlet (68) and outlet (70) ports to the heat exchange coil
(60). The header arrangement (66) comprises two longitudinally orientated headers
(72) and (73), the supply header (72) having an upper side mounted inlet tube (74)
and the return header (73) having a lower side mounted outlet tube (75). Of course,
in other embodiments, the inlet tube (74) and outlet tube (75) may be connected by
a common header arrangement. The heat exchange coil (60) and header arrangement are
mounted on a square base platform (78), which is typically constructed from galvanised
steel, reinforced concrete or the like.
[0061] The gap (66) in the first heat exchanger (60) forms two longitudinal ends (76) and
(77) of the heat exchange coil (60) between which a plurality of circumferentially
arranged thermally conductive tubing (79) extend. The ends of each circumferential
portion of tubing (79) is interconnected at various parts at each end using a U-bend
junction (80) to form a tortuous path carrying water from the supply header (72) to
the return header (73). The tubing (79) is mounted on a frame structure (82) mounted
in the base platform 78 which provides a predetermined spacing between each circumferential
length of tubing (79). This spacing is selected to allow air cooled by the air cooler
to flow from the outside of the first closed circuit heat exchanger (60) through the
sides of the closed circuit heat exchanger (60) and over the tubing (79).
[0062] In operation, a cooling fluid such as water, ammonia or Freon enters the closed circuit
heat exchanger (60) through the supply header (72) via inlet tube 74 and flows through
the tubing (79). Cooled air is forced over the tubing (79) through the action of fans
(for example fans (29 and 31)) in the embodiment shown in Fig. 1 or fans (54 and 56)
in the embodiment shown in Fig. 2 transferring heat from the water in the tubing (79)
to the tubing (79) (generally conductive heat transfer) through to the air (generally
convective heat transfer). The water in the tubing (79) is cooled and then is emitted
from the first closed circuit heat exchanger (60) through the return header (73) via
outlet tube (75).
[0063] Figs, 7 and 8 show two preferred embodiments of a heat exchange unit (82) and (84)
incorporating a closed circuit heat exchanger according to the present invention,
[0064] Referring first to the embodiment shown in Fig. 7, there is shown a front elevation
view of a low noise heat exchange unit (82). The heat exchange unit (82) is a self
contained unit which can be used individually or be coupled together with similar
heat exchange units (82) to form a heart exchange system for use in a roof top mounted
heat exchanger structure (23, 35) on a roof of a building (20, 34), such as is illustrated
in Figs. 1 and 2. The heat exchange unit (82) includes a first closed circuit heat
exchanger (60) as previously described. The first closed circuit heat exchanger (60)
is mounted on a base plate (85) constructed from sheets and sections of galvanised
steel. Vertically above the first closed circuit heat exchanger (60) is positioned
a centrally mounted electrically driven fan (86) arranged to draw cooled air through
the sidewalls of the first closed circuit heat exchanger (60). The fan (86) is centrally
mounted with its fan blade (87) rotatable about an axis which in turn is substantially
aligned with the longitudinal axis X-X of the closed circuit heat exchanger (60).
The fan (86) is orientated with the fan blades (87) directed downwardly away from
the fan motor (87A) toward the interior of the closed circuit heat exchanger (60).
In order to reduce vibration and noise caused by the operation of the fan (86), the
fan (86) is mounted in a cylindrical attenuating drum (88) formed from a dampening
material such as rubber or the like.
[0065] Arranged at two sides outward of the side walls of the closed circuit heat exchanger
(60) are located two substantially planar air coolers (89 and 90). The air coolers
(89, 90) are formed from moisture absorbent material which, which in one embodiment,
retains water when moisture is drip fed onto the air coolers (89 and 90) using a distribution
arrangement (not illustrated). The air coolers (89 and 90) are suspended over the
side walls, which form the air inlets of the closed circuit heat exchanger (60) such
that cooled air passing over the tubing (79) of the heat exchange coil (62) is required
to pass first through the air coolers (89 and 90). As described previously, evaporation
of the moisture extracts thermal energy from the air passing through the air coolers
(89 and 90) and therefore cools this air. The extent to which air is cooled, depends
upon the ambient temperature and humidity of the external air.
[0066] In an embodiment, a water absorbent material pad comprising a plurality of fluted
apertures of a size less than 7mm in diameter is used for the air coolers (89 and
90).
[0067] It should be understood that the air coolers (89 and 90) are typically moistened
by the application of water to the top of each of the air coolers (89 and 90) using
a moisture distributor (not illustrated) such as for example a control valve or the
like. The water applicator typically dispenses water over the top of air coolers (89
and 90). The water applied by the water applicator eventually trickles down through
the air coolers (89 and 90) substantially wetting the entire material of the air coolers
(89 and 90). In the event that the air coolers (89 and 90) do not fully absorb water
applied to them, run-off from the bottom of each air cooler (89 and 90) may be collected
in a tank (not illustrated) that may be returned to the water applicator via a pump
(also not illustrated). In some exemplary embodiments, the run-off from the bottom
of the air coolers is not recirculated to the top of the air cooler.
[0068] Referring now to the embodiment shown in Fig. 8, there is shown a front elevation
view of a standard configuration heat exchange unit (84). Like the heat exchange unit
shown in Fig. 7, this unit (84) is a self contained heat exchange unit which can be
used individually or be fluidly connected together with similar heat exchange units
(such as that shown in Fig. 7 or 8) to form a heat exchange system with a greater
heat exchange capacity as compared with a single self-contained heart exchange unit.
A structure such as that detailed in Fig 7 or 8 may be constructed on a roof of a
building, such as is illustrated in Figs. 1 and 2. The structure of the heat exchange
unit (84) is very similar to that described for the heat exchange unit (82) shown
in Fig. 7 and includes a closed circuit heat exchanger (60) as previously described,
a fan (92), air coolers (93 and 94) mounted on a base plate (85A). The difference
between the two embodiments shown in Figs. 7 and 8 relate to the orientation of the
fan (92) and the configuration of the mounting section (91) in which the fan (92)
is located. In this embodiment, the fan (92) is still centrally mounted with its fan
blade (95) rotatable about an axis which is substantially aligned with the longitudinal
axis X-X of the closed circuit heat exchanger (60). However, the fan (92) is not mounted
in a cylindrical attenuating drum (88), but rather a' cavity having a larger diameter
D than the internal diameter E of the closed circuit heat exchanger (60). This allows
the fan (92) to have a wider blade (95) and therefore draw a higher volumetric flow
rate through the closed circuit heat exchanger (60) as compared to the smaller fan
(86) of the heat exchange unit (82) shown in Fig. 7. In addition, the fan (92) is
orientated with the fan blades (95) directed upwardly away from the fan motor (95A)
and the interior of the closed circuit heat exchanger (60).
[0069] The heat exchange unit (82 and 84) shown in Figs. 7 and 8 can be connected with other
similar heat exchange units (82, 84) to form a modular heat exchange system. Figs.
9 to 12 shows the plan views of various modular arrangements of the heat exchange
units (82, 84), which will be referred to with reference to the reference numbers
of heat exchange unit (82) for ease of description. It should be understood that these
figures could equally be applicable to the heat exchange unit shown in Fig. 8.
[0070] Fig. 9 shows a plan of a single heat exchange unit (82), the heat exchange unit (82)
includes a circular tubular closed circuit heat exchanger (60'). It should be understood
that this tubular closed circuit heat exchanger (60') has all the same elements as
the closed circuit heat exchanger (60) illustrated in Figs. 3 to 6 but has a generally
circular lateral cross-section rather than a generally square lateral cross-section.
Figs. 10, 11 and 12 show the heat exchange unit (82) being interconnected into a series
of two, three and four heat exchange units (82) respectively.
[0071] The heat exchange units (82, 84) can be connected in series or parallel, and in one
embodiment, have an isolation circuit or fixtures between each heat exchange unit
(82, 84) allowing each individual heat exchange unit to be isolated and taken off
line for maintenance or replacement, while allowing the remaining heat exchange units
to still function. Accordingly, during such maintenance periods the roof top mounted
heat exchanger having these heat exchange units (82, 84) could still operate with
a reduced capacity.
[0072] In a particular application, the number of heat exchange units (82, 84) would be
selected to meet the maximum heat loading of a particular building or structure. In
this respect, the individual thermal capacity of the heat exchange units (82, 84)
would be known, and the maximum total thermal load from the air conditioning system
of the building can be estimated. The maximum capacity would generally be estimated
for the peak temperature loadings in summer. The number of heat exchange units (82,
84) used on the building would be selected to satisfy this maximum capacity.
[0073] In an exemplary embodiment, the size of the each heat exchange unit. (82, 84) shown
in Figs. 7 to 12 is dimensioned to allow that heat exchange unit (82, 84) to fit into
a standard goods lift. Typical dimensions would be for example 1420mm wide, 1420mm
long and 2015 mm high. These dimensions would allow the heat exchange unit (82, 84)
to be installed by loading the heat exchange unit (82, 84) in to a goods lift in a
building to move the heat exchange unit (82, 84) from the ground floor to the roof
of the building to where it is to be located. This can reduce installation costs as
compared with existing heat exchange systems, which are generally large apparatus
which need to be lifted onto the roof of a building using specialised lifting equipment
such as cranes. As can be appreciated, this can be an expensive exercise due to the
hiring of the crane and permits and compliance formalities involved in positioning
the crane at the base of a building, blocking roads and the like and lifting equipment
therefrom.
[0074] As can be seen in Figs. 7 to 12, each heat exchange unit (82, 84) has its own base
structure (85, 85A) and accordingly in most applications it is not necessary to construct
a new mounting structure on the roof the building, but rather the heat exchange unit
can be bolted or otherwise fixed to the existing roof structure.
[0075] In some embodiments, the air coolers (89 and 90) of each heat exchange unit (82,
84) are only operable when the ambient air temperature surrounding the heat exchange
unit is above a predetermined temperature. In these embodiments, the heat exchange
units (82 and 84) can include a controller that activates the use of the air coolers
(89 and 90). For example, the control methodology could wet the air coolers (89 and
90) for a short period of time on a regular or periodic basis when the temperature
of the cooling fluid emitted from the closed circuit heat exchanger rises above a
first predetermined limit. For example, the first predetermined limit could be 24
°C. The air coolers (89 and 90) would be wetted when cooling fluid temperature is
above the first limit until such time that the temperature of the cooling fluid emitted
from the closed circuit heat exchanger drops below a second predetermined limit. The
second predetermined limit is preferably at least 2 °C below the first predetermined
limit temperature to avoid the dispensers being constantly activated and deactivated
in response to small fluctuations in the temperature of the cooling fluid around the
predetermined limits.
[0076] Alternative control methodologies could be employed with the objective being to operate
the air coolers (89 and 90) for the least required time to accommodate the requirement
for an increased cooling capacity for the period of time that the increased cooling
capacity is required.
[0077] In other embodiments, variable pitch fans are used to draw air through the first
closed circuit heat exchanger and the air coolers.
[0078] A range of cooling fluids other than water could be used in the closed circuit of
a heat exchanger. In one alternative embodiment, the cooling fluid comprises highly
concentrated ammonia with a first closed circuit heat exchanger comprising stainless
steel or aluminium tubing effecting passage of the ammonia through the closed circuit
heat exchanger. Further, a range of materials could be used to form the passages for
the cooling fluid such as mild steel. As is understood in the art, the improved cooling
effect of a heat exchanger according to the present invention enables the construction
of a heat exchanger, comprising an ammonia cooling fluid, of a reduced physical size
with a similar cooling capacity as that for larger sized conventional heat exchangers.
As a result, closed circuit heat exchangers using ammonia as the cooling fluid become
a more economically feasible option for relatively small installations.
[0079] Fig. 13 shows an embodiment of the heat exchange unit (102) with the closed circuit
heat exchanger having four heat exchanger bodies (104) which comprises first, second,
third and fourth heat exchangers. The closed circuit heat exchangers are in fluid
communication through connecting channels (106). In this embodiment each of the heat
exchanger bodies (104) has next to it an air cooler (112) located upstream of the
closed circuit heat exchanger (104). Also shown is a fan arrangement (110) which causes
air to pass through the closed circuit heat exchangers and the air coolers. In this
embodiment, the fan arrangement has one fan (108) which is a six bladed fan.
[0080] Fig. 14 shows a detail of the heat exchange unit of Fig. 13 where an supply header
(114) is shown above one of the closed circuit heat exchangers for the inflow of cooling
fluid to the closed circuit heat exchanger (104).
[0081] Fig. 15 is a side view of one embodiment of a heat exchange unit (102). , In this
embodiment the closed circuit heat exchanger (104) is a duplex closed circuit heat
exchanger which has a first heat exchanger body (116) and a second heat exchanger
body (118) which are substantially parallel to each other so that air which is caused
to pass through the closed circuit heat exchanger passes over both the heat exchanger
bodies. Cooling fluid flows in at a first supply header (120) which then flows up
the first heat exchanger body (116) until it reaches a first outlet header (122).
This first outlet header (122) is in cooling fluid communication with a second supply
header (124) for the second heat exchanger body (118). The second supply header (124)
allows cooling fluid to flow down through the second heat exchanger panel until it
reaches a return header (126). The cooling fluid may then flow to another closed circuit
heat exchanger in the heat exchanger unit (102), alternatively it may flow to another
closed circuit heat exchanger in another heat exchanger unit (not shown), further
alternatively it may flow out to another part of the cooling system arrangement shown
in Fig. 1.
[0082] Fig. 16 shows a different orientation of the heat exchanger unit shown in Fig. 13.
[0083] Fig. 17 shows a different orientation of the detail of the heat exchange unit as
shown in Fig. 14.
[0084] The different orientations of the heat exchange units may be used to enhance exposure
of the heat exchangers and/or the air coolers to ambient air. This may enhance the
inflow and cooling characteristics of the heat exchange unit, especially when used
as a module in a modular heat exchange system of heat exchange units.
[0085] Fig. 18 is a side cross sectional view of a heat exchange unit (102) showing a fan
arrangement (110) at the top of the heat exchange unit and two closed circuit heat
exchangers (104) and two air coolers (112) at sides of the heat exchange unit.
[0086] Fig. 19 shows an embodiment of a closed circuit heat exchanger showing a planar side
(130) of the heat exchanger body (131).
[0087] Fig. 20 is a side view of the heat exchanger body (131) as shown in Fig. 19 with
planar sides facing both left (132) and right (130) relative to the page.
[0088] Fig. 21 shows a plan view of a modular heat exchange system (160)) with eight heat
exchange units (102). Cooling fluid is supplied to the modular heat exchange system
via a heat exchange system supply pipe (140). Each heat exchange unit (102) has an
inflow of cooling fluid from the heat exchange system supply pipe (140) via a heat
exchange unit supply pipe (142). The cooled cooling fluid flows out from each of the
heat exchange units (102) via a heat exchange unit return pipe (152). Each of the
heat exchange unit return pipes (152) allows the cooled cooling fluid to flow into
the heat exchange system return pipe (150). In the figure the direction of flow of
the cooling fluid has been marked on the pipes with arrows.
[0089] With reference to Figure 22, a diagrammatic representation of a modular heat exchange
system arrangement is provided wherein cooling fluid is passed through closed circuit
heat exchangers (225, 230) through an supply pipe (215) and subsequent to passing
through the closed circuit heat exchangers (225, 230) is emitted through an return
pipe (220), The cooling fluid may be water or a refrigerant fluid that is used to
transfer thermal energy such as Freon. Further, where the cooling fluid is water,
additives such as Glycol may be added to attempt to prevent freezing of the cooling
fluid. The cooling fluid is supplied to the closed circuit heat exchangers (225, 230)
through the supply pipe (215) for the purpose of cooling the cooling fluid and during
the passage through the closed circuit heat exchangers (225, 230) thermal energy is
extracted from the cooling fluid such that the fluid emitted through the return pipe
(220) has a substantially lower temperature and hence may be returned to a part of
the cooling system that uses the fluid for the purpose of absorbing and transferring
thermal energy.
[0090] During periods where the ambient air temperature is sufficiently low, air is drawn
through the closed circuit heat exchangers (225, 230) without the operation of the
air cooler. In this instance, the modular heat exchange system (210) is described
as running in the "dry" mode and thermal energy is extracted from the cooling fluid
solely by the action of passing air through the closed circuit heat exchangers (225,
230) as the cooling fluid (water/refrigerant) passes through the closed circuit heat
exchangers (225, 230).
[0091] However, during periods where the ambient air temperature is not sufficiently low,
or an increased heat exchange capacity is required that may not be effected by operating
a closed circuit heat exchanger in the "dry" mode, moisture absorbent material in
the form of air coolers (35, 40) are moistened by a moisture (preferably with water)
in order to effect evaporative cooling of the air prior to the passage of same through
the closed circuit heat exchangers (25, 30).
[0092] In the event that the air cooler is completely dry and has no water in the troughs
(255, 260) then the water make-up solenoid valve (270) is opened in order to introduce
external make-up water into the troughs (255, 260) through conduits (267, 265). The
external make-up water is provided to the water make-up solenoid valve (270) through
an inlet conduit (272). A back pressure flow prevention device (273) may be included
depending upon local installation regulations,
[0093] The troughs (255, 260) include a water level monitoring device generally in the form
of a flotation device that monitors the water level in the troughs (255, 260). Once
there is a sufficient water level in the troughs to maintain a positive head of pressure
to the inlet of the pump (245) then the pump may be operated to pump water through
a conduit (246) and provide same to water distribution arrangements (247, 250) for
distribution of the water to the upper portions of the air coolers (235, 240).
[0094] Of course, as water trickles down through the air coolers (235, 240) under the action
of gravity the moisture absorbent material in the air cooler absorbs the water and
once saturated any additional water provided to the air coolers (235, 240) will run-off
the moisture absorbent material. Ultimately, any run-off water will be collected in
the troughs (255, 260). The troughs (255, 260) have an overflow mechanism (280, 285)
in the event that there is a continuing supply of run-off water entering the troughs
(255, 260) despite the float monitoring device detecting a sufficient water level
in the trough and deactivating the water make-up solenoid valve (270). Over time,
as the evaporative cooling system operates, water is evaporated as it cools the ambient
air passing through the air coolers (235, 240) and any water lost through vaporization
is replaced by operation of the water make-up solenoid valve (270) in conjunction
with the float monitoring device in the troughs (255, 260). The moisture recirculation
system continues to operate as long as the modular heat exchange system (210) is required
to operate in "wet" mode.
[0095] A water dump valve (275) is also connected to the troughs (255, 260) by a conduit
(265). The water dump valve is operated on a regular basis for the purpose of dumping
the contents of the troughs (255, 260) to reduce the potential for the generation
and growth of bacteria that may result from an increase in concentration of sediment
and/or impurities in the troughs (255, 260). This is particularly the situation when
water is used as the moisture.
[0096] The particular arrangement of a recirculation system detailed in Figure 22 is very
common and has been used successfully for many decades. However, this standard arrangement
of a moisture recirculation system has disadvantages including a relatively large
trough capacity. In this respect, Figure 22 is an end perspective and the troughs
(255, 260) extend the entire length of the air coolers (235, 240). In the event that
the closed circuit heat exchanger is relatively long, the sump capacity is commensurably
large and in order to maintain a positive head of water pressure at the inlet side
of the pump (245) it is necessary to maintain a minimum depth of water in the troughs
(255, 260). For a relatively long trough, maintaining the minimum depth may represent
a substantial amount of water. Further, a separate disadvantage of existing arrangements
is the relatively long period of time that is required to transition the modular heat
exchange system (210) from "dry" to "wet" mode as a result of the supply of external
make-up water to the troughs (255, 260).
[0097] An embodiment of the present invention with a moisture recirculation system for wetting
the air coolers is detailed in Figure 23 which provides a diagrammatic representation
from a similar end perspective as that of Figure 22.
[0098] With reference to Figure 23, a cooling fluid that requires cooling is provided to
closed circuit heat exchangers (325, 330) through a supply pipe (315). As the fluid
passes through the closed circuit heat exchangers (325, 330) thermal energy is extracted
therefrom and cooled cooling fluid is emitted from the bottom of the closed circuit
heat exchangers (325, 330). Cooled cooling fluid is returned through a return pipe
(320). Just as for the arrangement detailed in Figure 22, the modular heat exchange
system (300) extracts thermal energy from the cooling fluid by passing same through
the closed circuit heat exchangers (325, 330) whilst passing ambient air through the
closed circuit heat exchangers. In the event that the ambient air temperature is not
sufficiently low, or an increased heat exchange capacity is required, the device detailed
in Figure 23 is transitioned from "dry" mode to "wet" mode by the application of moisture
(preferably water) to the air coolers (335, 340) such that the air coolers evaporatively
cool the ambient air. The cooled air then passes through the closed circuit heat exchangers
(325, 330).
[0099] In the arrangement detailed in Figure 23, when seeking to transition the arrangement
to "wet" mode, the water make-up solenoid valve (370) is activated to allow external
water that is supplied through conduit (372) to pass through conduits (346 and 349)
until the external make-up water reaches and passes through the water distribution
arrangements (348, 350). The external make-up water then trickles down through the
moisture absorbent material of the air coolers (335, 340) and is absorbed by same.
As ambient air passes through the air coolers (335, 340) the air is cooled by the
action of evaporation as the water that was initially absorbed by the moisture absorbent
material is then vapourised and converted from liquid to gaseous form.
[0100] In order to ensure that the air coolers (335, 340) are completely saturated, a sufficient
amount of water is provided to the water distribution arrangements (348, 350) such
that water, trickles down through the evaporative air coolers (335, 340) and runs-off
the air coolers into the respective collecting troughs (355, 360). The collecting
troughs (355, 360) act as a temporary and intermediate collection of run-off water
which is then provided, through conduits to the sump (365). The sump does not need
to extend the full length of the air coolers (335, 340) and may be dimensioned to
have a capacity that is substantially smaller as compared with the standard trough
capacity (as detailed in Figure 22). The sump (365) collects the run-off water from
the collecting troughs (355, 360) and upon collecting enough run-off water to provide
a sufficient head of pressure to the intake of the pump (345) then the pump may be
activated to pump run-off water up through conduits (346, 349) and re-distribute the
water collected in the sump (365) to the water distribution arrangements disposed
above the air coolers (348, 350). A back pressure flow prevention device (347) may
be included.
[0101] The water make-up solenoid valve (370) may be activated as a result of a water level
monitoring device in the form of a flotation device in the sump (365). A back pressure
flow prevention device (371) may be included. In any event, as water is depleted from
the evaporative air cooling system, the water level in the sump (365) decreases and
when sufficiently low (such that a positive head of pressure will not be maintained
at the pump intake) the make-up solenoid valve (370) is activated to introduce replacement
make-up water into the system. In the embodiment of Figure 23, the make-up water is
deposited directly onto the top of the air coolers where it is most directly needed.
As run-off is collected in the collecting troughs (355, 360) and passed to the sump
(365), the water level in the sump increases.
[0102] Again, as for the apparatus detailed in Figure 22, upon expiry of a period of time
the water dump valve (375) is activated to release the entire contents of the sump
(365) to reduce the likelihood of the generation and growth of bacteria and slime
in the sump (365). However, as the sump (365) is dimensioned to have a substantially
lower capacity as compared with the sump of a standard arrangement, the amount of
water that is discharged as a result of a dumping operation is commensurately substantially
less.
[0103] In embodiments where the make-up water is provided directly to the water distribution
arrangements (348, 350) thus effectively by-passing the sump (365), the arrangement
provides even less delay in achieving fully saturated air coolers (335, 340) as compared
with the existing arrangements.
[0104] With reference to Figure 24, a perspective view of the cooling system of Figure 23
is provided. The same parts in Figures 23 and 24 are identified by use of the same
identification number.
[0105] Figure 24 details various parts of the cooling system in perspective and of particular
importance is the extension of the collecting troughs (355, 360) extending the entire
length of the air coolers (335, 340), Further, the water collected by the collecting
troughs, (355, 360) is subsequently passed to the sump (365) for collection and storage.
As will be noted in Figure 24, the dimensions of the sump (365) are substantially
smaller as compared with the dimensions of the collecting troughs (355, 360) and therefore,
the sump (365) has a significantly reduced volumetric capacity as compared with the
collecting troughs (355, 360). Accordingly, if the troughs (355, 360) were used to
collect and store run-off, it would require substantially more water (as compared
with the sump (365)) to maintain a minimum head of pressure at the intake of a pump.
[0106] In industrial and commercial applications, the air coolers (335, 340) can be relatively
large. In these applications, it is not unusual for the air coolers (335, 340) to
comprise a number of smaller cooling pads that are placed in abutment with one another
thus forming a wall that extends for a sufficient length and height to substantially
conform with the dimensions of the closed circuit heat exchangers (325, 330). Accordingly,
the collecting troughs (355, 360) must extend along the full length of the air coolers
(335, 340) in order to collect any water run-off from the air coolers (335, 340).
[0107] However, in the embodiment, of Figures 23 and 24, the collecting troughs (355, 360)
may act as a temporary collection and storage means for water run-off and may pass
run-off water to the sump (365) for collection and storage. As a result, the volumetric
water holding capacity of the collecting troughs (355, 360) can be substantially reduced
as compared with existing collection and storage troughs that must both collect and
store run-off water and maintain a sufficient head of pressure at a pump intake.
[0108] Having passed run-off water to the sump (365) the water is pumped (345) up through
backflow pressure prevention device (347) and through the conduits to the water distribution
arrangements (348, 350) whereby water is distributed to the upper portion of the air
coolers (335, 340).
[0109] Those skilled in the art will appreciate that the invention described herein is susceptible
to variations and modifications other than those specifically described. It is understood
that the invention includes all such variations and modifications which fall within
the scope of the appended claims.
[0110] The reference to any prior art in this specification is not, and should not be taken
as, an acknowledgment or any form or suggestion that the prior art forms part of the
common general knowledge of persons skilled in the relevant field of technology at
the priority date of the claims herein.
1. A modular heat exchange system (160) comprising:
at least two heat exchange units (102) each having at least one first heat exchanger
(104) having a closed circuit for cooling the fluid therein;
at least one air cooler (112) located upstream of the at least one first heat exchangers
located in each of the at least two heat exchange units;
at least one first fan arrangement (110) operable to cause air to pass through the
at least one air coolers (112) and the at least one first heat exchangers (104);
wherein the at least one air coolers (112) include moisture absorbent material; and
the at least one first heat exchangers (104) of each of the at least two heat exchange
units (102) are micro-channel heat exchangers in fluid communication allowing flow
of cooling fluid therebetween.
2. A modular heat exchange system (160) according to claim 1 comprising:
a first heat exchange unit (102) including:
at least one first heat exchanger (104) having a closed circuit for cooling the fluid
therein;
at least one air cooler (112) located upstream of the first heat exchanger;
at least one fan arrangement (110) operable to cause air to pass through the at least
one air cooler (112) and the at least one first heat exchanger (104);
at least one further heat exchange unit including:
at least one further heat exchanger having a closed circuit for cooling the fluid
therein;
at least one further air cooler located upstream of the at least one further heat
exchanger;
at least one further fan arrangement operable to cause air to pass through the at
least one further air cooler located upstream of the at least
one further heat exchanger;
characterised in that
the at least one air cooler (112) and the at least one further air cooler include
moisture absorbent material; and the modular heat exchange system comprises:
at least one channel providing cooling fluid interconnection between the first heat
exchanger (104) located within the first heat exchange unit (102) and the further
heat exchanger located within the further heat exchange unit, wherein the first heat
exchanger (104) and further heat exchanger are microchannel heat exchangers.
3. A heat exchange system (160) according to either claim 1 or claim 2, wherein the at
least one first heat exchanger (104) includes at least one fluid carrying passage,
and wherein the fluid carrying passage type is any one of plate, plate-fin, spiral,
tube, double-pipe or coil arrangement.
4. A heat exchange system (160) according to any one of claims 1 to 3, wherein the at
least one first heat exchanger (104) includes at least one first and at least one
second microchannel heat exchanger modules.
5. A heat exchange system according to claim 4, wherein the at least one first and second
heat exchanger modules are arranged such that surfaces of the first module are substantially
parallel to surfaces of the second module, and the first module and the second module
are aligned such that flow of the air passes through the first module and subsequently
through the second module, and wherein the cooling fluid is arranged to flow through
the first module and subsequently through the second module.
6. A heat exchange system (160) according to any one of claims 1 to 5, wherein the at
least one first heat exchanger (104) includes fluid carrying passages extending between
vertical sides of the at least one first heat exchanger (104).
7. A heat exchange system (160) according to any one of claims 1 to 6, wherein the cooling
fluid is any one or more of water, oil, ammonia, Freon and carbon dioxide.
8. A heat exchange system (160) according to any one of claims 1 to 7, wherein the at
least one first heat exchanger (104) is configured such that it forms a substantially
cross-sectional tubular arrangement with an internal space through which the air can
pass.
9. A heat exchange system (160) according to claim 9, wherein the tubular arrangement
has a substantially cross-sectional shape including any one of: generally square,
generally hexagonal, generally octagonal, generally star-shaped, generally triangular,
generally circular, generally rectangular and generally oval.
10. A heat exchange system (160) according to either claim 8 or claim 9, wherein the tubular
arrangement has a structure which extends circumferentially wholly around the longitudinal
axis of the tubular arrangement.
11. A heat exchange system (160) according to any one of claims 8 to 10, wherein the tubular
arrangement has a structure which extends circumferentially partially around the longitudinal
axis of the tubular arrangement.
12. A heat exchange system (160) according to any one of claims 1 to 11, wherein the moisture
absorbent material in air cooler (112) is in the form of moisture absorbent pads,
and wherein the air cooler (112), when in use, is maintained moist with moisture such
that the air passing through the air cooler is cooled by the action of evaporation
prior to passing over a portion of the at least one first heat exchanger (104).
13. A heat exchange system according to claim 12, wherein the moisture absorbent material
includes a plurality of fluted apertures.
14. A method of installation of a modular heat exchange system according to any one of
claims 1 to 13 wherein the method comprises:
transporting one or more heat exchange units (102) to an installation location;
connecting the one or more heat exchange units (102) to a cooling fluid supply;
connecting the one or more heat exchange units (102) to a power supply; and
activating the modular heat exchange system.
1. Modulares Wärmetauschsystem (160), umfassend:
mindestens zwei Wärmetauscheinheiten (102) mit jeweils mindestens einem ersten Wärmetauscher
(104) mit einem geschlossenen Kreislauf zum Kühlen des Fluids darin;
mindestens einen Luftkühler (112), der sich stromaufwärts der mindestens einen ersten
Wärmetauscher befindet, die sich in jeder der mindestens zwei Wärmetauscheinheiten
befinden;
mindestens eine erste Lüfteranordnung (110), die so betrieben werden kann, dass Luft
durch die mindestens einen Luftkühler (112) und die mindestens einen ersten Wärmetauscher
(104) strömt; wobei
die mindestens einen Luftkühler (112) feuchtigkeitsabsorbierendes Material enthalten;
und die mindestens einen ersten Wärmetauscher (104) jeder der mindestens zwei Wärmetauscheinheiten
(102) Mikrokanal-Wärmetauscher in Fluidverbindung sind, die einen Fluss von Kühlfluid
dazwischen ermöglichen.
2. Modulares Wärmetauschsystem (160) nach Anspruch 1, umfassend:
eine erste Wärmetauscheinheit (102), enthaltend:
mindestens einen ersten Wärmetauscher (104) mit einem geschlossenen Kreislauf zum
Kühlen des Fluids darin;
mindestens einen Luftkühler (112), der sich stromaufwärts des ersten Wärmetauscher
befindet; mindestens eine Lüfteranordnung (110), die so betrieben werden kann, dass
Luft durch den mindestens einen Luftkühler (112) und den mindestens einen ersten Wärmetauscher
(104) strömt;
mindestens eine weitere Wärmetauscheinheit, enthaltend:
mindestens einen weiteren Wärmetauscher mit einem geschlossenen Kreislauf zum Kühlen
des Fluids darin;
mindestens einen weiteren Luftkühler, der sich stromaufwärts des mindestens einen
weiteren Wärmetauschers befindet;
mindestens eine weitere Lüfteranordnung, die so betrieben werden kann, dass Luft durch
den mindestens einen weiteren Luftkühler, der sich stromaufwärts des mindestens einen
weiteren Wärmetauschers befindet, strömt; dadurch gekennzeichnet, dass
der mindestens eine Luftkühler (112) und der mindestens eine weitere Luftkühler feuchtigkeitsabsorbierendes
Material enthalten; und das modulare Wärmeaustauschsystem umfasst:
mindestens einen Kanal, der eine Kühlfluidverbindung zwischen dem ersten Wärmetauscher
(104), der sich in der ersten Wärmetauscheinheit (102) befindet, und dem weiteren
Wärmetauscher, der sich in der weiteren Wärmetauscheinheit befindet, bereitstellt,
wobei der erste Wärmetauscher (104) und der weitere Wärmetauscher Mikrokanal-Wärmetauscher
sind.
3. Wärmetauschsystem (160) nach Anspruch 1 oder Anspruch 2, wobei der mindestens eine
erste Wärmetauscher (104) mindestens einen Fluidtransportkanal enthält und wobei der
Fluidtransportkanaltyp einer von einer Platten-, Rippenplatten-, Spiral-, Röhren-,
Doppelrohroder Spulenanordnung ist.
4. Wärmetauschsystem (160) nach einem der Ansprüche 1 bis 3, wobei der mindestens eine
erste Wärmetauscher (104) mindestens ein erstes und mindestens ein zweites Mikrokanal-Wärmetauschermodul
enthält.
5. Wärmetauschsystem nach Anspruch 4, wobei das mindestens eine erste und das zweite
Wärmetauschermodul so angeordnet sind, dass die Oberflächen des ersten Moduls im Wesentlichen
parallel zu den Oberflächen des zweiten Moduls sind und das erste Modul und das zweite
Modul so ausgerichtet sind, dass der Luftstrom durch das erste Modul und anschließend
durch das zweite Modul strömt, und wobei das Kühlfluid so angeordnet ist, dass es
durch das erste Modul und anschließend durch das zweite Modul strömt.
6. Wärmetauschsystem (160) nach einem der Ansprüche 1 bis 5, wobei der mindestens eine
erste Wärmetauscher (104) Fluidtransportkanäle enthält, die sich zwischen vertikalen
Seiten des mindestens einen ersten Wärmetauschers (104) erstrecken.
7. Wärmetauschsystem (160) nach einem der Ansprüche 1 bis 6, wobei das Kühlfluid eines
oder mehrere von Wasser, Öl, Ammoniak, Freon und Kohlendioxid ist.
8. Wärmetauschsystem (160) nach einem der Ansprüche 1 bis 7, wobei der mindestens eine
erste Wärmetauscher (104) so konfiguriert ist, dass er eine im Wesentlichen querschnittsröhrenförmige
Anordnung mit einem Innenraum bildet, durch den die Luft strömen kann.
9. Wärmetauschsystem (160) nach Anspruch 8 wobei die röhrenförmige Anordnung eine im
Wesentlichen Querschnittsform aufweist, einschließlich einer von: im Allgemeinen quadratisch,
im Allgemeinen sechseckig, im Allgemeinen achteckig, im Allgemeinen sternförmig, im
Allgemeinen dreieckig, im Allgemeinen kreisförmig, im Allgemeinen rechteckig und im
Allgemeinen oval.
10. Wärmetauschsystem (160) nach Anspruch 8 oder Anspruch 9, wobei die röhrenförmige Anordnung
eine Struktur aufweist, die sich in Umfangsrichtung vollständig um die Längsachse
der röhrenförmigen Anordnung erstreckt.
11. Wärmetauschsystem (160) nach einem der Ansprüche 8 bis 10, wobei die röhrenförmige
Anordnung eine Struktur aufweist, die sich in Umfangsrichtung teilweise um die Längsachse
der röhrenförmigen Anordnung erstreckt.
12. Wärmetauschsystem (160) nach einem der Ansprüche 1 bis 11, wobei das feuchtigkeitsabsorbierende
Material in dem Luftkühler (112) in der Form von feuchtigkeitsabsorbierenden Kissen
vorliegt und wobei der Luftkühler (112), wenn er verwendet wird, mit Feuchtigkeit
so feucht gehalten wird, dass die durch den Luftkühler strömende Luft durch die Wirkung
einer Verdampfung gekühlt wird, bevor sie über einen Teil des mindestens einen ersten
Wärmetauschers (104) strömt.
13. Wärmetauschsystem nach Anspruch 12, wobei das feuchtigkeitsabsorbierende Material
mehrere geriffelte Öffnungen enthält.
14. Verfahren zur Installation eines modularen Wärmetauschsystems nach einem der Ansprüche
1 bis 13, wobei das Verfahren umfasst:
Transportieren einer oder mehrerer Wärmetauscheinheiten (102) zu einem Installationsort;
Verbinden der einen oder mehreren Wärmetauscheinheiten (102) mit einer Kühlfluidversorgung;
Verbinden der einen oder mehreren Wärmetauscheinheiten (102) mit einer Stromversorgung;
und
Aktivieren des modularen Wärmetauschsystems.
1. Système modulaire d'échange de chaleur (160) comprenant :
au moins deux unités d'échange de chaleur (102) comportant chacune au moins un premier
échangeur de chaleur (104) possédant un circuit fermé pour refroidir le fluide en
son sein ;
au moins un aéroréfrigérant (112) situé en amont dudit au moins un premier échangeur
de chaleur se trouvant dans chacune desdites au moins deux unités d'échange de chaleur
;
au moins un premier ensemble ventilateur (110) servant à faire passer de l'air à travers
ledit au moins aéroréfrigérant (112) et ledit au moins premier échangeur de chaleur
(104) ;
ledit au moins un aéroréfrigérant (112) comprenant un matériau absorbant l'humidité
; et
ledit au moins un premier échangeur de chaleur (104) de chacune desdites au moins
deux unités d'échange de chaleur (102) étant des échangeurs de chaleur à micro-canaux
en communication fluidique permettant l'écoulement d'un fluide de refroidissement
entre eux.
2. Système modulaire d'échange de chaleur (160) selon la revendication 1 comprenant :
une première unité d'échange de chaleur (102) comportant :
au moins un premier échangeur de chaleur (104) possédant un circuit fermé pour refroidir
le fluide en son sein ;
au moins un aéroréfrigérant (112) situé en amont du premier échangeur de chaleur ;
au moins un ensemble ventilateur (110) servant à faire passer de l'air à travers ledit
au moins un aéroréfrigérant (112) et ledit au moins un premier échangeur de chaleur
(104) ;
au moins une unité d'échange de chaleur supplémentaire comportant :
au moins un échangeur de chaleur supplémentaire possédant un circuit fermé pour refroidir
le fluide en son sein ;
au moins un aéroréfrigérant supplémentaire situé en amont dudit au moins un échangeur
de chaleur supplémentaire ;
au moins ensemble ventilateur supplémentaire servant à faire passer de l'air à travers
ledit au moins un aéroréfrigérant supplémentaire situé en amont dudit au moins échangeur
de chaleur supplémentaire ;
caractérisé en ce que
ledit au moins un aéroréfrigérant (112) et ledit au moins un aéroréfrigérant supplémentaire
comporte un matériau absorbant l'humidité ; et
le système modulaire échangeur de chaleur comprend :
au moins un canal assurant l'interconnexion du fluide de refroidissement entre le
premier échangeur de chaleur (104) se trouvant dans la première unité d'échange de
chaleur (102) et l'échangeur de chaleur supplémentaire se trouvant dans l'unité d'échange
de chaleur supplémentaire, ledit premier échangeur de chaleur (104) et ledit échangeur
de chaleur supplémentaire étant des échangeurs de chaleurs à micro-canaux.
3. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 ou
2, ledit au moins un premier échangeur de chaleur (104) comportant au moins un passage
de transport de fluide et le type de passage de transport de fluide étant l'un quelconque
parmi un plateau, à plaques-ailettes, un serpentin, un tube, un double-tube ou un
ensemble bobine.
4. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 à 3,
ledit au moins un premier échangeur de chaleur (104) comportant au moins un premier
et au moins un second module échangeur de chaleur à micro-canaux.
5. Système d'échange de chaleur selon la revendication 4, lesdits au moins un premier
et second modules échangeurs de chaleur étant agencés de sorte que les surfaces du
premier module soient pratiquement parallèles aux surfaces du second module, et ledit
premier module et ledit second module étant alignés de sorte que l'écoulement d'air
traverse le premier module et ensuite traverse le second module, et ledit fluide de
refroidissement étant conçu pour s'écouler à travers le premier module et ensuite
à travers le second module.
6. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 à 5,
ledit au moins un premier échangeur de chaleur (104) comportant des passages de transport
de fluide s'étendant entre des côtés verticaux dudit au moins un premier échangeur
de chaleur (104).
7. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 à 6,
ledit fluide de refroidissement étant l'un quelconque ou plusieurs parmi l'eau, l'huile,
l'ammoniac, le fréon et le dioxyde de carbone.
8. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 à 7,
ledit au moins un premier échangeur de chaleur (104) étant conçu de sorte qu'il forme
un agencement tubulaire pratiquement transversal avec un espace interne à travers
lequel l'air peut passer.
9. Système d'échange de chaleur (160) selon la revendication 8, ledit agencement tubulaire
ayant une forme pratiquement transversale comportant l'une quelconque parmi : globalement
carrée, globalement hexagonale, globalement octogonale, globalement en forme d'étoile,
globalement triangulaire, globalement circulaire, globalement rectangulaire et globalement
ovale.
10. Système d'échange de chaleur (160) selon l'une quelconque des revendications 8 ou
9, ledit agencement tubulaire ayant une structure qui s'étend circonférentiellement
complètement autour de l'axe longitudinal de l'agencement tubulaire.
11. Système d'échange de chaleur (160) selon l'une quelconque des revendications 8 à 10,
ledit agencement tubulaire ayant une structure qui s'étend circonférentiellement en
partie autour de l'axe longitudinal de l'agencement tubulaire.
12. Système d'échange de chaleur (160) selon l'une quelconque des revendications 1 à 11,
ledit matériau absorbant l'humidité dans l'aéroréfrigérant (112) se présentant sous
la forme de tampons absorbant l'humidité, et ledit aéroréfrigérant (112), lors de
son utilisation, étant maintenu humide avec l'humidité de sorte que l'air traversant
l'aéroréfrigérant soit refroidi par l'action de l'évaporation avant de passer sur
une partie dudit au moins un premier échangeur de chaleur (104).
13. Système d'échange de chaleur selon la revendication 12, ledit matériau absorbant l'humidité
comportant une pluralité d'ouvertures cannelées.
14. Procédé de montage d'un système modulaire d'échange de chaleur selon l'une quelconque
des revendications 1 à 13, ledit procédé comprenant :
le transport d'une ou plusieurs unités d'échange de chaleur (102) vers le lieu de
montage ;
le raccordement desdites une ou plusieurs unités d'échange de chaleur (102) à une
alimentation de fluide de refroidissement ;
le branchement desdites une ou plusieurs unités d'échange de chaleur (102) à une alimentation
électrique ; et
l'activation du système modulaire d'échange de chaleur.