Note: Descriptions are shown in the official language in which they were submitted.
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BOILER CONDENSATION MODULE
The present invention relates to a boiler condensation module.
More specifically, the invention reiates to a device of the above
kind that, when installed inside, or connected with, a methane- or G.P.L.-,
or Diesel oil- fed heating boilers, or with another kind of boiler, picks up
the
exhaust fumes from the combustion, positively exploiting the residual heat.
At present, most used boilers are the so-called "high-efficiency
boilers". These apparatuses can exploit up to a 95% of the combustible
calorific power, loosing only 5% of the total heat. They are used for
feeding high temperature systems, i.e. systems employing standard
radiators and/or fan coils, i.e. elements requiring, for a proper operation, a
thermal vector (water) with temperatures above 70 C. Said boilers cannot
recover combustion latent heat of vaporisation, i.e. heat that would be
recovered transforming vapour produced during the combustion into liquid
form.
Some of the most important gas boiler manufacturers produce
the "condensation boilers", i.e. particular boilers that, by a normally upset,
particular burner, and one increased efficiency smoke/water heat
exchanger, can bring the combustion fumes under the so-called "dew
point" varying between 25 C and 55 C (that can vary on the basis of the
combustible, of the air-combustible mixture and of the CO2 emitted); under
said temperature, vapour contained within the fumes starts condensing,
thus yielding a great amount of heat. It is important underlying that latent
condensation heat is equal to 11 % of the total heat from the methane
combustion. For this reason, without any dispersion, a condensation boiler
can theoretically have a calorific efficiency of 111 % with respect to the
caiorific power (100% sensitive heat + 11 % condensation latent heat).
However, these apparatuses reach very high efficiencies of
103% - 106% only if employed in low temperature systems (floor coils)
with a temperature of the circulating thermal vector (water) of 35 C -
C, or applying some specific solutions (reducing the temperature
and/or flow rate of the thermal vector, limiting the boiler power). Anyway, if
the temperature of these boilers is kept at a value of 60 C - 80 C
35 (necessary to make a system with radiators or fan coils working properly)
the condensation boiler does not succeed recovering the vaporisation
latent heat since water inlet temperature is higher or too close to the fume
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dew temperature: in this case, condensation boiler operates as a standard
high efficiency boiler (efficiency 85% - 95%).
In view of the above, it is suggested according to the present
invention an apparatus permitting to recover part of the sensitive heat and
part of the condensation latent heat (also known as vaporisation latent
heat) contained within the large vapour amounts produced by the
combustion.
Heat recovered by the described apparatus will be used to pre-
heat the thermal vector contained within the tubes of the heating system
(usually water) that, from the final users (radiators, ventilation -
convectors, radiating tubes, ecc) enters again within the boiler to be then
heated and sent again to the final users (but it is also possible use the
same for other applications). This permits that the boiler uses less energy
to increase the thermal vector at the set temperature, thus obtaining a
saving of fuel with the same energy obtained from the system.
Apparatus according to the invention employs a water/fume
exchanger with a compression thermodynamic cycle allowing recovering a
high amount of heat until cooling the fumes (even up to about +35 C) and
transferring said heat to the thermal vector with a different temperature
(even beyond + 80 C).
It is therefore specific object of the present invention a boiler
condensation module, characterised in that it comprises a water/fume heat
exchanger and a closed circuit compression thermodynamic frigorific
apparatus, said module being communicated with a boiler intercepting the
flow of the fumes and the flow of the water, in order to subtract sensitive
heat and vaporisation latent heat to the fumes of the boiler to yield the
same as heat to the system water thus improving the combustion
efficiency.
Preferably, according to the invention, said heat exchanger is of
the water/fume plate or laminar unit type.
Furthermore, according to the invention, said frigorific
apparatus is a compression thermodynamic frigorigen apparatus,
particularly, comprised of a fume-refrigerant or evaporator heat exchanger,
of an exchanger, of a refrigerant compressor, of a expansion or lamination
member, of a control electric - electronic system.
Still according to the invention, said closed circuit compression
thermodynamic frigorific apparatus provides an evaporation temperature
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included between 12 C and 20 C and a condensation temperature
variable between 50 C and 95 C.
Particularly, said frigorigen machine comprises one or more
water - refrigerant heat exchanger of the plate and/or laminar unit and/or
tube bundle type; one or more fume - refrigerant heat exchangers of the
plate and/or laminar unit and/or tube bundle type; one or more
compressors, even of the inverter type, suitable to compress R12, R134,
R404, R407, R410, R125 refrigerant fluids and like as heat; one or more
lamination members of the capillary and/or thermostatic expansion valve
type, with or without pressure equaliser and/or calibrated choke; metallic
tubes connecting the various components.
Furthermore, according to the invention, parts that can be
directly in touch with the fume condensate are comprised of material
resisting to the acid corrosion due to the same condensate, e.g. AISI 316L
stainless steel, or other suitable materials.
Still according to the invention, one or more water/fume plate or
laminar unit type heat exchangers are provided, with or without the
thermal exchange with the carburant air.
Further, according to the invention, said water - fume heat
exchanger and said fume - refrigerant heat exchanger (evaporator for the
frigorific circuit) are installed inside a metallic room within which fumes
circulate, realised in such a way that condensate produced by the two heat
exchangers can easily outflow outside said metallic room, avoiding that a
mixing of air, environment, water and fumes occurs.
Furthermore, protection and control fittings are provided, that
are usually used in frigorific circuits such as: pressure switches,
thermostats, flow-meters, manometers, thermometers, transducers, fume
extractors, passage indicators, fans, liquid injection systems, liquid
receivers and dividers, filters, electric/electronic boards, pressure
equalisers and reducers, interception and adjustment valves, mixing
valves, condensate exhaust siphons.
Particularly, fluid R134A is employed as refrigerant fluid, or, as
alternative, various refrigerant fluids can be employed (R404, R407, R410,
R125) circulating within the frigorific circuit.
Still according to the invention, a volumetric or centrifugal
compressor of the hermetic, semi-hermetic or open type is provided.
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Always according to the invention, another fluid or a mixture
comprising glycol or another anti-freezing liquid is used instead of water as
thermal vector of the system.
Furthermore, according to the invention, transfer (transmission)
of the heat recovered from the fumes occurs to the fluid of another system
not directly connected with the system of the main water, for example for
heating the sanitary heat water and/or for feeding another heating system
and/or for directly heating air.
Finally, according to the invention, counter current flow heat
exchangers can be used.
"Condensation boiler module" according to the present
invention aims obtaining for a standard high efficiency boiler (not a
condensation boiler) the same advantages of a condensation boiler (low
consumption, very high efficiency and low emissions), and at the same
time solving the two main drawbacks: high costs and good operation only
with low water temperature within the system.
Apparatus according to the invention permits recovering
condensation latent heat, even maintaining a high temperature of the
thermal vector (60 C - 80 C). This permits avoiding expensive
modifications of the system for delivering the thermal vector and of the
final devices (radiators - fan coils) that would be necessary in case of
installation of a condensation boiler on an already existing heating system.
Only a small percentage of the existing heating systems is realised with a
floor diffusion, while at present 95% of systems are provided with cast iron
or aluminium radiators, where the provision of a condensation boiler is not
convenient.
The present invention will be now described, for illustrative but
not limitative purposes, according to its preferred embodiments, with
particular reference to the figures of the enclosed drawings, wherein:
figure 1 is a schematic view of a boiler provided with a
condensation module according to the invention; and
figure 2 particularly shows the condensation module of figure 1.
Observing the enclosed figures, it is shown a boiler 1, with a
condensation unit 2 according to the invention. As shown in figure 1 for
exemplificative purposes, module according to the invention can be
applied as outer component according to the scheme boiler 1, boiler
condensation module 2, radiators 3, water delivery tubes 4 to the users,
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water return tubes 5 from the users, boiler fume exit 6, flue 7, condensate
exhaust 8.
Observing particularly figure 2, it is shown a condensation
module 2 for a boiler according to the invention, substantially comprising a
5 water/fume plate or laminar unit type heat exchanger E and a frigorific
apparatus of the compression thermodynamic type.
Said frigorigen apparatus is comprised of a fume-refrigerant or
evaporator heat exchanger G(evaporator), of a refrigerant compressor H,
of an expansion or lamination member L, of a control electric - electronic
system and of various functional fittings usually used in the frigorific
systems, that are not specific object of the present invention.
Fumes arriving from the boiler (not shown), enter within the
boiler condensation module 2, into the metallic room P through the hole C,
at a temperature of about 150 C, meeting in sequence the fume/water
heat exchanger E, where, due to the thermal exchange with water, cools
up to 90 C, and then, the fume-refrigerant heat exchanger G, where they
are further cooled, since refrigerant circulates at a temperature lower than
C.
Fumes cool in this heat exchanger G up to about 35 C, thus
20 permitting that vapour contained in the same condenses with the
consequent recover of the vaporisation latent heat.
Finally, fumes exit from the metallic room P through the hole D,
possibly pushed by the fan/extractor N compensating the higher flow
resistance and the lack of draft due to the low temperature.
Water coming from the system at about 60 C enters through
joint A, passes first within the water - refrigerant heat exchanger F, thus
being pre-heated up to about 62 - 64 C due to the high temperature of the
refrigerant (about 110 C), and then passes within the water - fume heat
exchanger E, further heating (possibly up to 64 C - 67 C), since it
exchanges heat with fumes up to 150 C.
Finally, water exits from the boiler condensation module by joint
B through tube Q. Under standard conditions, said pre-heated water is
destined to go back into the boiler, that will require less fuel to increase
the
temperature just for the previous pre-heating.
Refrigerant (usually R134A or a similar fluid) is contained in a
watertight circuit. Compressor H compresses fluid as vapour at a pressure
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(16 - 22 bar) necessary to obtain that the vapour has the water
temperature when entering again within the final users.
Overheated vapour enters within the water - refrigerant heat
exchanger F through the high-pressure tube I; refrigerant yields heat to
water, said water heating while refrigerant cools under its saturation
temperature (referred to its specific pressure) changing state and
becoming in liquid form. Now, refrigerant meets the lamination member L,
aiming to reduce its pressure (about 3.5 - 4.5 bar) in order to lower its
saturation temperature (12 C - 13 C) and at the same time its real
temperature.
Thus, refrigerant is in a liquid - vapour saturated mixture state
and, through the low pressure tube M, enters within the fume - refrigerant
heat exchanger G; here, refrigerant receives heat from fumes (cooling up
to 35 C - 40 C) permitting state passage into vapour of the remaining
liquid part of the refrigerant. Refrigerant is thus sucked by compressor H to
start again the cycle.
"Boiler condensation module" according to the invention can be
installed within a forced draught boiler or into a blown air burner during its
manufacturing or it can be provided in an already existing heating system,
intercepting boiler fumes and the boiler inlet water tube.
Condensation of fumes occurs only inside the module 2 thus
preserving boilers with respect to damages due to the condensate acidity.
It is well evident that . recovered heat can be used for different
objects with respect to that or pre-heating water for the boiler.
"Boiler condensation module" according to the invention can be
realised for different powers in order to be suitable for boilers having
different sizes and employing different fuels. In fact, also the type of fuel
influences the power of the inventive solution since, with the same lower
calorific power, the upper calorific power is not the same.
"Boiler condensation module" according to the invention has the
advantage of transforming a standard boiler into a very high efficiency
boiler thanks to the almost complete recover of the heat (sensitive and
latent heat) usually dispersed into the atmosphere. In fact, without wasting
energy, consumption of fuel is reduced at the minimum level, as well as
the emissions are proportionally reduced with respect to the reduction of
fuel consumption.
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Polluting substances are further kept into the condensation
water formed during the operation both because some components are
soluble and because of the specific surface-active power of the same
condensation water.
By the operation of the system with inlet water warmer than
35 C, boiler provided with "boiler condensation module" has efficiency
higher than the traditional condensation boilers. Boiler condensation
module is cheap and simple to realise and allows obtaining a very
interesting performance/price ratio.
The present invention has been described for illustrative but not
limitative purposes, according to its preferred embodiments, but it is to be
understood that modifications and/or changes can be introduced by those
skilled in the art without departing from the relevant scope as defined in
the enclosed claims.
