Note: Descriptions are shown in the official language in which they were submitted.
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"Air-conditioning system for rooms"
FIELD OF THE INVENTION
The present invention refers to an air-conditioning
system for rooms according to the pre-characterizing
portion of claim 1.
BACKGROUND OF THE INVENTION
In order to improve the healthiness of the human body
the air of a room within a house should have particu-
lar features, for instance an hygrometric degree of
50% to 60%. As a matter of fact, in such conditions
the human body can adjust its own temperature through
condensing and dissipating mechanisms.
In order to meet such requirements within a house,
i.e. to have pleasant environmental conditions, that
is to feel warm in winter and cool in summer, two
separate independent hydraulic circuits for heating
and cooling are necessary, in the first of which hot
water and in the second one cold water circulates.
In order to heat or cool the house it is therefore
necessary to have a boiler and a cooling unit, each of
which is equipped with its own electric and hydraulic
supply and with its own control system.
The house should be heated during winter in all the
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rooms it is made up of, whereas it should be cooled
during summer only in some rooms, i.e. those which are
used more frequently, leaving aside for instance the
bathroom and the kitchen. This requires quite differ-
s ent operating features in both systems concerning ca-
pacity, pump flow rate, pressure drop during water
supply and so on.
In order to overcome this disadvantage systems have
been developed which can ensure heat and/or cold using
the same hydraulic circuit. Indeed, this type of sys
terns is associated with a cooling unit, which works
during summer in order to circulate within the common
hydraulic circuit cold water bypassing the boiler, and
during winter the cooling unit is bypassed so that hot
water can flow within said hydraulic circuit.
For instance Patents US 2,121,625, US 2,984,460, US
3,425,485, US 3,906,742, US 4,798,240 and DE 2,140,018
describe central heating and cooling installations
comprising a plurality of heat exchangers, each of
which being arranged in a room of the various houses.
In particular, said heat exchangers are connected to a
single boiler and to a single cooling device.
In recent years manufacturers of heating and cooling
systems for block of flats or small detached houses
have introduced integrated or monobloc systems in
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which a single system gathers up the functions of
cooler and boiler using a single unit equipped with
exchangers.
Such type of systems disadvantageously has a high
thermal inertia, which can occur within an air-
conditioning system.
The solution suggested by said manufacturers in order
to overcome such drawback was to use a system compris-
ing a boiler circulating heating water through the
heat exchanging units placed in the rooms to be heated
by means of a hydraulic circuit, a cooling module as-
sociated to said boiler and an inertial reservoir
(also known as storage reservoir).
This inertial reservoir acts as reserve of cooled wa
ter allowing to increase the system capacity and to
obtain a longer life for cooling machines due to a
smaller number of starts of said machines.
The introduction of the storage reservoir therefore
enables a higher flexibility due to the possibility of
operating also at temperatures slightly differing from
design temperature, and above all enables a great op-
erating economy due to the possibility of installing
machines with reduced power.
Therefore, when in air-conditioning systems the prob-
lem of a low thermal inertia arises, it is sufficient
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to place an inertial reservoir between the cooling
group and the system. This type of reservoir thus al-
lows to increase the water content of the whole system
ensuring a longer interval between the stop of the
compressor and a subsequent start, thus highly reduc-
ing the number of starts and improving the life and
performance of said compressor.
However, since the monobloc unit is bulky, cumbersome
and noisy, it should almost always be arranged outside
the house to be conditioned, so that during summer the
removed heat is not dispersed within the room itself.
This however results in that during winter, in
order to avoid the freezing of the water contained
within the storage reservoir, particular contrivances
should be used in order to prevent possibly destruc-
tive damages to the system due to the increase of wa-
ter volume.
One of the most frequently used solutions provides
that the storage reservoir is equipped with a water
inlet/outlet valve, i.e. with a valve allowing the
reservoir to be completely emptied before winter and
with a valve allowing said reservoir to be re-filled
bef ore summer .
This results in long and boring filling/emptying op-
erations of the reservoir to be absolutely carried out
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to prevent the system from being damaged. However,
said solution does not protect the heating and cooling
system in case the user forgets to carry out said op-
erations.
Another solution to prevent water contained in the in-
ertial reservoir from freezing consists in using elec-
tric heaters, which keep water within the reservoir
liquid, thus ensuring that the heating and cooling
system cannot be damaged due to the user's careless-
ness or to a very cold weather.
Electric heaters are for instance electric resistors
that in order to carry out their function must absorb
electric energy and turn it into heat. Obviously, such
a contrivance results in that part of the advantages
obtained with a storage reservoir are erased by the
dissipation of energy necessary to supply said elec-
trio resistors. The dissipation of electric energy
will be higher the greater the reservoir volume and
the colder winter weather is.
SUMMARY OF THE INVENTION
In the light of the described state of the art, the
present invention aims at carrying out an air-
conditioning system for external use without the dis-
advantages of prior art.
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A further aim of the present invention is to supply an
integrated heating and cooling unit that requires the
least possible maintenance by the user.
According to the present invention said aim is
achieved by means of an air-conditioning system for
rooms according to claim 1.
Thanks to the present invention it is possible to
carry out an air-conditioning system that is more ef-
ficient and therefore environmentally friendlier than
systems of prior art.
Moreover, it is possible to carry out an air-
conditioning unit that does not require maintenance
operation during season shifts.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristics and the advantages of the present
invention will be evident from the following detailed
description of one of its practical embodiments, shown
as a mere non-limiting example in the enclosed draw-
ings, in which:
Figure 1 shows schematically a preferred embodi-
ment of the air-conditioning system according to the
present invention;
Figure 2 shows schematically a layout of a compo-
nent of Figure 1, in particular a layout of a gas
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boiler;
Figure 3 shows schematically a first operating
configuration during summer of the air-conditioning
system of Figure 1;
Figure 4 shows schematically a second operating
configuration during winter of the air-conditioning
system of Figure 1.
Figure 1 shows schematically an embodiment of the
present invention consisting of a block 1 comprising a
cooling circuit 2, a control unit 3 and a storage res
ervoir 4, a heating system 8 associated to said block
1 and a plurality of fan-convectors F1, ..., Fn.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The block 1 and the heating system 8 thereto associ-
ated constitute the monobloc system that integrates
all components for heating/conditioning the house.
As can be noted from the diagram in Figure 1, the
cooling circuit 2 is connected by means of a connec
tion pipe A to a three-way switching valve Vi, the
latter being able to connect said cooling circuit 2 to
a plurality of fan-convectors F1, ..., Fn by means of
a intake pipe 5.
Said cooling circuit 2 is further connected by means
of a connection pipe B to a circulation pump P1; said
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circulation pump P1 takes water to circulate in the
cooling system 2 from the storage reservoir 4 by means
of a connection pipe C.
Said storage reservoir 4 is connected in its turn to a
plurality of fan-convectors F1, . . . , Fn by means of a
return pipe 7.
Furthermore, as can be inferred from the diagram of
Figure 1, the storage reservoir 4 has in common with
said plurality of fan-convectors F1, ..., Fn the con-
nection to the heating system 8, which takes place by
means of a connection pipe D.
Therefore, the connection pipe D is the extension of
the return tube 7 of the fan-convectors F1, ..., Fn.
The control of the cooling circuit 2, of the fan-
convectors Fl, . . . , Fn as well as of the heating sys-
tem 8 is in charge of the electronic control unit 3,
said control unit 3 being able to control all devices
by means of a plurality of electric connections 9 in a
per se known way.
By analyzing in further detail what is included within
the cooling circuit 2, the latter consists of a com
pressor 10, of a capacitor 11, of a lamination element
12 (or capillary) and of an evaporator 13, each of
said components being connected to the other by means
of connection pipes E.
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The compressor 10 is the core of the cooling circuit 2
and its function is to compress a cooling fluid, for
instance freon or halogenated fluids, and to bring it
to high pressure by heating it.
In the present invention, for instance, a rotary com-
pressor is used; whose great advantage with respect to
traditional compressors is the absence of alternating
movements and therefore of vibrations, thus ensuring
silence and absence of vibrations to the user's imme
l0 diate comfort.
Downstream from the compressor 10 an exchanger 14 is
connected, on which a fan 15 is axially placed.
Said exchangers 14 are finned-tube exchangers and con
silt for instance of tubes made of scored copper or of
stainless steel. The fins of the exchangers (not shown
in Figure 1) can be made for instance of aluminum,
copper or aluminum treated for environments with ag-
gressive agents.
At the outlet of the exchangers 14 the cooling fluid,
which is 1_iquid, gets through the lamination element
12.
The lamination element 12 (also known as capillary)
enables, as is well known, the expansion of the fluid
and further allows to adjust the flow rate of said
fluid.
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Said lamination element 12 consists for instance of a
copper tube with a length of 1-2 meters, wound on it-
self and having a diameter of some tenths of millime-
ter.
It should also be noted that the lamination element 12
is preceded by a dehydrating filter 12a and is fol-
lowed by a silencer 12b. The function of the dehydrat-
ing filter 12a is to eliminate water residues from the
cooling fluid, thus ensuring the compressor 10 a
longer life, whereas the function of the silencer 12b,
which can be for instance an absorption or resonance
silencer, is to soften noises made by the cooling cir-
cuit 2 as a whole.
The passage of the cooling fluid through the tube con-
stituting the lamination element 12 results in a pres-
sure reduction, without allowing a heat exchange with
outside. The cooling fluid is therefore brought to an
evaporation temperature, which is far lower that room
temperature.
The cooling fluid gets through the evaporator 13,
which is carried out for instance using the technol-
ogy, well known to a technician skilled in the art, of
exchangers with welded-brazed plates.
The evaporator 13 is structurally the same as the ca-
pacitor 11 but has an exactly symmetrical function
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with respect to the latter; here the cooling liquid
changes in opposite direction, i.e. shifts from liquid
to vapor by absorbing heat from the environment.
Therefore, the cooling fluid overheated at a high
pressure gets from the compressor to the capacitor,
then starts giving heat to the colder room air getting
through it, i.e. at first temperature sinks due to the
discharge of sensitive heat, until the state of satu-
rated vapor is reached, i.e. constant pressure P and
temperature T. This stage is followed by the condens-
ing of the fluid, i.e. the state shift, from vapor to
saturated liquid by means of the plate evaporator 13.
To summarize, the working of the cooling circuit 2
provides that the compressor 10 compresses the cooling
fluid (here as gas) at low temperature and pressure,
for instance T = +7°C and P = 5 bar, and brings said
cooling fluid, always as gas, to high temperature and
pressure, for instance T = 100°C, P = 16 bar.
From now on the cooling fluid is sent to the capacitor
14 by means of the connection pipe E, which is also
for instance made of copper, and within said device
take place first the cooling, for instance up to about
T = 40°C, and then the state shift from gas to liquid,
with the consequent heating of outside air.
During this stage the latent heat of condensation is
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given to a colder outside fluid, i.e. air in our case.
After the capacitor 14 the cooling fluid, now liquid,
though always at high pressure, gets through the lami-
nation element 12, which as already described is a
capillary, thus turning from high pressure, for in-
stance P = 16 bar, to low pressure, for instance P = 5
bar, though always liquid.
The cooling fluid, now liquid, at low pressure and low
temperature, for instance P = 5 bar and T = +7°C, gets
out of the condensing unit and is led to the evapora
for 13 through connection pipes.
Within the evaporator 13 evaporation at low pressure
and low temperature takes place, i.e. little below P =
5 bar and T = +7°C, so that the cooling fluid shifts
from vapor to liquid, boiling and absorbing heat. Thus
the fluid with which it is put in contact through the
walls of the evaporator 13 cools down, i.e. the air of
the room, which is thus cooled.
The cooling fluid must turn completely into gas within
this evaporator and then, by getting through the con-
nection pipes in the opposite direction, gets back to
the compressor 10.
It should further be noted that the cooling circuit
described above from the static and dynamic point of
view can also comprise other devices so as to work as
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a heat pump.
In this case the lamination element 12 consists, as is
well known to a technician in the field, of a capil-
lary for cold operation, an additional capillary for
heat pump operation and a unidirectional bypass valve.
A four-way valve for cycle inversion and a storage
reservoir for cooling liquid should also be present.
The cooling circuit 2, as already described, is con-
netted to the fan-convectors F1, ..., Fn through the
three-way switching (or mixing) valve V1 by means of
the intake pipe 5.
The valve V1 is equipped with an electric motor (not
shown in Figure 1), and on the basis of the electric
signals sent by the electronic control unit 3 to said
electric motor (which can be for instance an incre-
mental motor) said three-way valve V1 can be
opened/closed.
This can be obtained thanks to the shifting of a shut-
ter (not shown in Figure 1), so as to create a sort of
narrowing of the fluid pipes with subsequent distribu-
tion of water flows in the intake pipes.
The valve V1 therefore allows the fluid connection
through the intake pipe 5 to the fan-convectors F1,
..., Fn acting as heating/cooling terminals whose ra-
diant kit will be supplied according to the present
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invention with hot water during winter and with cooled
water during summer.
These tan-convectors F1, ..., Fn generate a forced air
flow by means of the fan 16 they are equipped with,
which flow involves the whole room generating an ac
tive air circulation, preventing the formation of
stagnant areas and stratifications and keeping a
pleasant and uniform air movement.
Each fan-convector F1, ..., Fn is equipped with a
thermostat (not shown in Figure 1) so as to adjust
temperature and with a speed variator fox the fans 16
allowing to choose the speed of thermal adjustment for
the room.
Thus this type of installation allows the user to con
trol the air-conditioning wholly independently for
each room, though it is a centralized system.
The three-way switching valve V1 is also connected, as
already described, to the connection tube D acting as
return tube of the heating system 8.
The heating system 8 can be for instance an independ-
ent gas boiler or a centralized installation or a dis-
trict heating system (not shown in Figure 1).
Figure 2 shows the layout of a gas boiler comprising
an inner hydraulic circuit including a heat exchanger
17, a series of burners 18 supplied by a tube 19 in
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which a throttle valve 20 is arranged, a circulation
pump 21, a hot water heater 22 for domestic hot water
getting into the tube 23 and out of the tube 24
through the tap 25, an expansion vessel 26, a three-
s way valve 27 and a throttle valve 28 to bypass the
boiler during summer.
The boiler 8 comprises also the connection pipe D act
ing as intake tube and the connection pipe E acting as
return tube for the connection to the cooling circuit
2.
The three-way valve 27 is controlled by a transducer
29 fitted into the outlet tube 24 of the hot water
heater 22. This transducer 29 automatically switches
the three-way valve 27 so as to put in communication
hot water getting out of the heat exchanger 17 with
the hot water heater 22 whenever the tap 25 is opened
for supplying hot water for domestic use.
Examining now Figures 3 and 4, which show schemati
tally a first and second operating configuration, dur
ing summer and during winter respectively, of the air
conditioning system of Figure 1 according to the pre
sent invention, it can be advantageously noted that
the central branch of the three-way switching valve V1
is always connected to the inlet or intake branch 5 of
the fan-convectors F1, ..., Fn.
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As a matter of fact, referring in particular to Figure
3, i.e. to the working of the installation of Figure 1
during summer, the working of the air-conditioning
system provides that the throttle valve 28 is closed
and that the cooling circuit 2 is operated by the con-
trol unit 3 so as to circulate the cooling fluid
within the heat exchanger in said cooling circuit 2.
The three-way valve V1 is switched by the control unit
3, i.e. by the electronic control unit, so as to con-
nest the connection tube A of the cooling circuit 2,
more precisely the outlet tube of the evaporator 13,
to the fan-convectors F1, ..., Fn through the intake
tube 5.
Simultaneously, the control unit 3 actuates the pump
P1 so that water coming back from the fan-convectors
F1, ..., Fn gets through the evaporator 13 of the
cooling circuit 2 and then reaches the finned-tube ex
changer 14. The refrigerated water is stored in the
storage reservoir 4 before reaching the batteries of
the fan-convectors F1, ..., Fn.
In other words, the storage unit 4 acts in this first
operating configuration as storage unit for cold water
getting out through the connection pipe B in the
evaporator 13 to enter into the intake pipe 5 of the
fan-convectors F1, .., Fn.
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Cold water, after getting through the fan-convectors
F1, ,.., Fn, is led back through the return pipe 7
into the storage reservoir 4 so as to be re-circulated
through the evaporator 13 by means of the pump P1.
Since the fans 16 of the fan-convectors F1, ..., Fn
can be operated separately by the control unit 3, it
is possible to cool during summer either all rooms in
the house or only the rooms chosen by the user.
For instance it is possible to cool during the day
only the living-room by operating the fan 16 of the
fan-convector placed in the living-room, and during
the night only the bedroom by operating the fan 16 of
the fan-convector placed in the bedroom, while cold
water is circulated in all fan-convectors F1., ..., Fn.
Obviously, the cooling circuit 2 includes, as is well
known to a technician in the field, all safety de-
vices, not shown in Figures 1-4, that are required by
the regulations on accident prevention.
Referring now to Figure 4, i.e. to the working of the
installation of Figure 1 during winter, it should be
noted that water coming back from the fan-convectors
F1, ..., Fn through the return pipe 7 is deviated by
the three-way valve V1 so as to reach the boiler 8
through the connection tube C.
The boiler 8 allows to heat the rooms of each detached
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house or block of flats since water within the hydrau-
lic circuit leading to the fan-convectors F1, ..., Fn
(i.e. intake tube 5) is circulated by the pump 21
within the boiler 8.Hot water can thus circulate in
the fan-convectors F1, ..., Fn and therefore heats the
rooms of the house, whereas the cooling circuit 2 ac-
cording to the present invention is bypassed by means
of the three-way valve V1.
As a matter of fact, the control unit 3 does not
switch on the pump 1 and the cooling circuit 2.
Advantageously, in this second operating configuration
the storage reservoir 4 does not act any more as cold
water storage unit but as thermal inertia for water
contained within the evaporator 13.
As a matter of fact, should water heated by the boiler
8 reach directly the evaporator 13, the cooling fluid
therein contained would reach extremely high pressures
that are not compatible with the characteristics of
mechanical and thermal resistances of said evaporator
13.
Since the cooling unit, i.e. the block 1 comprising
the cooling circuit 2, the control unit 3 and the
storage reservoir 4, is placed outside the house, no
problem arises involving the freezing of the connec-
tion tubes during winter, because the latter do not
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contain water but a cooling fluid that does not
free ze .
As far as the storage reservoir 4 is concerned, the
latter does not freeze during winter because hot water
coming back from the fan-convectors F1, ..., Fn heats
by convection the content of said reservoir 4 prevent-
ing its freezing.
This can take place since water Gaming back from the
fan-convectors F1, ..., Fn is at a temperature of
about T = 60°C, and by exploiting the configuration of
the new hydraulic circuit it is possible by means of
the convective effect, convection being a phenomenon
involving typically fluids by means of macroscopic
substance transport, to heat water contained in the
storage reservoir 4 without using auxiliary solutions
and/or devices.
Thus, hot water within the return tube 5 of the fan
convectors F1, ..., Fn by convection can keep water
contained in the storage reservoir 4 liquid (i.e. pre
vents its freezing) also during winter.
Thanks to the present invention it is possible to ob-
tain a storage reservoir 4 without inlet/outlet tap
and/or electric heaters, thus carrying out an air-
conditioning system that is more ef f icient and there-
fore environmentally friendlier than installations of
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prior art, and further carrying out an air-
conditioning system that does not require maintenance
operating during season shifts.
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