FIELD OF THE INVENTION
[0001] The invention relates to heat exchangers for air conditioning and heat pump applications.
In particular, it relates to heat exchangers for use in automotive industry.
BACKGROUND OF THE INVENTION
[0002] There are known heat exchangers adapted to work in so-called AC mode (air conditioning
mode). In AC mode, the heat exchanger works as an ordinary condenser. The refrigerant
at the inlet at a typical operation point is in gaseous state and needs to be cooled
inside the core in order to deliver liquid, subcooled refrigerant at outlet. For this
mode, the cores are usually configured in manner ensuring that number of tubes in
first pass is significantly greater than number of tubes in second pass. Number of
tubes in second pass may be usually 8-12 when total number of tubes may be equal or
above 60 for some specific application. This solution is beneficial, because it allows
decrease in pressure drop in first pass, where density of refrigerant is small and
consequently the volumetric flow is significant. At inlet to the second pass the refrigerant
is condensed, i.e. it is fluid or mostly fluid, while its density is significantly
higher and in connection to that volumetric flow is also significantly lower.
[0003] Such configuration allows a decent compromise in terms of size/performance ratio.
[0004] There are also known heat exchangers adapted to work in a so-called HP mode (heat
pump mode). In the HP mode, the temperature of refrigerant at inlet is lower than
temperature of air flowing through the core. Refrigerant is heated inside core and
in the second pass temperature of refrigerant is higher and due to that density is
smaller than in the first pass.
[0005] While it is preferable to enable flow from top to bottom within the heat exchanger
adapted for AC mode, it is preferable to enable flow from bottom to top within the
heat exchanger adapted for HP mode.
[0006] It is possible to use a single heat exchanger, in particular an evapo-condenser,
which operates alternatively in the AC and HP mode. For such application, the flow
through this heat exchanger can be reversed between the modes, or can be maintained
common for both. From the system point of view, it may be preferable to have a common
direction of flow in both modes. An example of such system is described in
EP2933586.
[0007] Consequently, it is clear that there may be a conflict between the requirements posed
by the system and those related to optimal performance during operation in each of
the modes.
[0008] It would be desirable to provide a heat exchanger adapted to work both in the AC
mode and the HP mode in an effective manner, without requiring the reversal of the
direction of the fluid flow.
SUMMARY OF THE INVENTION
[0009] The object of the invention is, among others, a heat exchanger comprising a first
manifold and a second manifold connected by a bundle of tubes, configured to provide
an inlet pass, an outlet pass and an intermediate pass for a heat exchange fluid,
characterized in that the heat exchanger comprises controlling means adapted to switch
between a first state, in which co-flow of the heat exchange fluid in the outlet pass
and the intermediate pass with counterflow in the inlet pass is enabled, and a second
state in which co-flow of the heat exchange fluid in the inlet pass and the intermediate
pass with counterflow in the outlet
[0010] Preferably, the heat exchanger is further comprising an inlet port associated with
the inlet pass and an outlet port associated with an outlet pass, wherein both are
located on the first manifold.
[0011] Preferably, the flow between the inlet pass, the intermediate pass and the outlet
pass is blocked within the second manifold, wherein the heat exchanger further comprises
an outside channel, the outside channel being adapted to receive the fluid from and
distribute the fluid to the inlet pass, intermediate pass and the outlet pass.
[0012] Preferably, the outside channel is adapted to receive the fluid from and distribute
the fluid to the inlet pass, intermediate pass and the outlet pass at places which
promote the flow through and from specific tubes within the pass, while hindering
the flow through and from the remaining ones.
[0013] Preferably, the outside channel is fluidly connected to the second manifold such
that there is a first opening at the level of the inlet pass, a second opening at
the level of the intermediate pass, and a third opening at the level of the outlet
pass to enable flow between the passes and the manifold.
[0014] Preferably, each of the openings is located in the lower section of respective pass.
[0015] Preferably, the heat exchanger further comprises a tubular body connected fluidically
to the first manifold so that it can receive the fluid from and distribute the fluid
to the inlet pass, intermediate pass and the outlet pass, wherein the tubular body
comprises the controlling means.
[0016] Preferably, the controlling means comprise a valve assembly, the valve assembly comprising
two baffles connected to each other and adapted to cooperate with the tubular body
so that in the first state they block fluid flow between the inlet pass and the intermediate
pass, and in the second state they block fluid flow between the intermediate pass
and the outlet pass.
[0017] Preferably, the controlling means are adapted to switch between the first state and
the second state based on temperature of the core and/or environment of the heat exchanger.
[0018] Another object of the invention is an air conditioning circuit comprising a heat
exchanger as described above.
BRIEF DESCRITPTION OF DRAWINGS
[0019] Examples of the invention will be apparent from and described in detail with reference
to the accompanying drawings, in which:
Fig. 1 shows the heat exchanger in heat pump mode;
Fig. 2 shows the heat exchanger in air conditioning mode.
DETAILED DESCRIPTION OF EMBODIMENTS
[0020] Figs. 1 and 2 present heat exchanger according to the invention, wherein Fig. 1 shows
the heat exchanger in heat pump mode, while Fig. 2 shows the heat exchanger in air
conditioning mode.
[0021] A heat exchanger 1 comprises a first manifold 2 and a second manifold 3 connected
by a bundle of tubes 4. The heat exchanger is configured to provide an inlet pass
5, an outlet pass 6 and an intermediate pass 7 for a heat exchange fluid, the intermediate
pass 7 being located between the inlet pass 5 and the outlet pass 6. The tubes 4 within
the bundle are spaced with respect to each other to enable heat exchange with a second
fluid, for example air, travelling through the spaces between the tubes. Said spaces
may comprise fins for facilitating the heat exchange. The heat exchanger 1 further
comprises an inlet port 8 associated with the inlet pass 5 and an outlet 9 port associated
with an outlet pass 6, wherein both are located on the first manifold 2. The heat
exchanger 1 further comprises controlling means 50 adapted to switch between a first
state, in which co-flow of the heat exchange fluid in the outlet pass 6 and the intermediate
pass 7 with counterflow in the inlet pass 5 is enabled, and a second state in which
co-flow of the heat exchange fluid in the inlet pass 5 and the intermediate pass 7
with counterflow in the outlet pass 5 is enabled. This may be done by selectively
blocking the flow between the passes by the controlling means 50.
[0022] The controlling means 50 are adapted to receive the fluid from and distribute the
fluid to the inlet pass 5, intermediate pass 7 and the outlet pass 6. One example
of implementation of controlling means adapted for switching between the first state
and the second state may be integrating them into or with a tubular body 10 connected
fluidically to the first manifold 2 so that it can receive the fluid from and distribute
the fluid to the inlet pass 5, intermediate pass 7 and outlet pass 6. The controlling
means 50 may comprise a valve assembly with two baffles 41, 42 connected to each other
(for example by a rod 43), and adapted to cooperate with the tubular body 10 so that
in the first state they block fluid flow between the inlet pass 5 and the intermediate
pass 7, and in the second state they block fluid flow between the intermediate pass
7 and the outlet pass 6. The switching between the first and second states may be
controlled automatically or manually. Other ways of effecting the blocking and enabling
the flow as explained above are also possible as long as they allow to execute reliably
the functioning of the heat exchanger.
[0023] The flow between the inlet pass 5, the intermediate pass 7 and the outlet pass 6
may be blocked within the second manifold 3. The heat exchanger then further may comprise
an outside channel 11, the outside channel 11 being adapted to receive the fluid from
and distribute the fluid to the inlet pass 5, intermediate pass 7 and the outlet pass
6. The outside channel 11 then is fluidly connected to the second manifold 3 such
that there is a first opening 31 at the level of the inlet pass 5, a second opening
32 at the level of the intermediate pass 7, and a third opening 33 at the level of
the outlet pass 6. Preferably, the outside channel 11 is adapted to receive the fluid
from and distribute the fluid to the inlet pass 5, intermediate pass 7 and the outlet
pass 6 at places which promote the flow through and from specific tubes within the
pass, while hindering the flow through and from the remaining ones of said pass. For
example, each of the openings 31, 32, 33 is located in the lower section of respective
pass 5, 7, 6.
[0024] For the heat exchanger according to the invention, in HP mode the controlling means
50 are set to the first state. The refrigerant enters the heat exchanger through the
inlet port 8 and then travels through the inlet pass 5. The fluid then is turned and
flows in the intermediate pass 7 as well as the outlet pass 6, as allowed by the controlling
means 50, both in a direction opposite to the direction within the inlet pass 5. The
fluid then may exit the heat exchanger through the outlet port 9.
[0025] In AC mode the controlling means are set in the second state. The refrigerant enters
the heat exchanger through the inlet port 8 and then travels through the inlet pass
5, as well as the intermediate pass 7 in the same direction, as allowed by the controlling
means 50. The fluid then is turned and flows in the outlet pass 6 in a direction opposite
to the direction within the inlet and intermediate passes 5, 7. The fluid then may
exit the heat exchanger through the outlet port 9.
[0026] In both AC and HP mode, the switching between the first state and the second state
allows to achieve optimal performance, connected to the amount of tubes within passes,
without reversing the flow within the same heat exchanger.
[0027] The controlling means 50 can be driven based on temperature, e.g. thermostatic valve
or pressure e.g. pressure valve. Thermostatic valve can be beneficial due to fact
that with system in a switch of state, it will adjust its position according to more
probable position. For example, it will switch to AC mode in summer when temperature
of the environment and/or core will be high, or HP mode when temperature of the environment
and/or the core will be low, for example in winter.
[0028] Others configurations of valves e.g. rotating valve, actuators e.g. driven by various
factors, including solenoid, core, repartition of tubes, number of passes etc. can
be used.
[0029] It is also envisaged for the invention to pertain to heat exchangers with more than
three passes as explained above. In such scenarios, the inlet, intermediate and outlet
passes may be neighbored by further passes, and necessarily be directly connected
to inlet and/or outlet ports. Nevertheless, the general concept can still be applicable.
[0030] Other variations to the disclosed embodiments can be understood and effected by those
skilled in the art in practicing the claimed invention, from a study of drawings,
the disclosure, and the appended claims. The mere fact that certain measures are recited
in mutually different dependent claims does not indicate that a combination of these
measures cannot be used to the advantage.
1. A heat exchanger 1 comprising a first manifold 2 and a second manifold 3 connected
by a bundle of tubes 4, configured to provide an inlet pass 5, an outlet pass 6 and
an intermediate pass 7 for a heat exchange fluid, characterized in that the heat exchanger 1 comprises controlling means 50 adapted to switch between a first
state, in which co-flow of the heat exchange fluid in the outlet pass 6 and the intermediate
pass 7 with counterflow in the inlet pass 5 is enabled, and a second state in which
co-flow of the heat exchange fluid in the inlet pass 5 and the intermediate pass 7
with counterflow in the outlet pass 5 is enabled.
2. A heat exchanger according to claim 1, further comprising an inlet port 8 associated
with the inlet pass 5 and an outlet 9 port associated with an outlet pass 6, wherein
both are located on the first manifold 2.
3. A heat exchanger according to any preceding claim, wherein the flow between the inlet
pass 5, the intermediate pass 7 and the outlet pass 6 is blocked within the second
manifold 3, wherein the heat exchanger further comprises an outside channel 11, the
outside channel 11 being adapted to receive the fluid from and distribute the fluid
to the inlet pass 5, intermediate pass 7 and the outlet pass 6.
4. A heat exchanger according to claim 3, wherein the outside channel 11 is adapted to
receive the fluid from and distribute the fluid to the inlet pass 5, intermediate
pass 7 and the outlet pass 6 at places which promote the flow through and from specific
tubes within the pass, while hindering the flow through and from the remaining ones.
5. A heat exchanger according to claim 4, wherein the outside channel 11 is fluidly connected
to the second manifold 3 such that there is a first opening 31 at the level of the
inlet pass 5, a second opening 32 at the level of the intermediate pass 7, and a third
opening 33 at the level of the outlet pass 6 to enable flow between the passes and
the manifold 3.
6. A heat exchanger according to claim 5, wherein each of the openings 31, 32, 33 is
located in the lower section of respective pass 5, 7, 6
7. A heat exchanger according to any preceding claim, wherein it further comprises a
tubular body 10 connected fluidically to the first manifold 2 so that it can receive
the fluid from and distribute the fluid to the inlet pass 5, intermediate pass 7 and
the outlet pass 6, wherein the tubular body comprises the controlling means 50.
8. A heat exchanger according to any preceding claim, wherein the controlling means 50
comprise a valve assembly, the valve assembly comprising two baffles 41, 42 connected
to each other and adapted to cooperate with the tubular body 10 so that in the first
state they block fluid flow between the inlet pass 5 and the intermediate pass 7,
and in the second state they block fluid flow between the intermediate pass 7 and
the outlet pass 6.
9. A heat exchanger according to any preceding claim, wherein the controlling means 50
are adapted to switch between the first state and the second state based on temperature
of the core and/or environment of the heat exchanger.
10. An air conditioning circuit comprising a heat exchanger according to any preceding
claim.