Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The invention relates to a heating unit for hot water room hea ing
systems.
In this context a hot water room heating system is defined as any
heating system in which a liquid heat medium is constantly circulated in a
closed pipe system and is supplied to heat radiators. The heat medium is
generally water but can also be oil or some other suitable fluid.
It is a substantial disadvantage of known room heating systems
that a large proportion of the thermal energy generated in the room-heat_ng
combustion system escapes unused together with the exhaust gases of the
combustion system. This disadvantage applies both to combination heating
systems in which a boiler containing the heat medium is heated by a central
combustion system to supply an entire house, and individual heating systems
in which a separate combustion system is provided for each room that is to
be heated. This disadvantage exists irrespective of whether coal, oil, gas
or some other fuel is used in t:he combustion system.
The unutilized escape at high temperature of the exhaust gases
of the combustion system result:s in an unnecessary waste of energy which is
exceptionally inefficient in view of the high energy costs and the limited
energy reserves. Moreover, the exhaust gases which escape at elevated
temperature lead to serious environmental pollution, particularly in densely
populated areas.
It is therefore the object of the invention to reduce such energy
waste and to utilize the thermal energy produced in room-heating combustion
systems more completely in an efficient manner.
The invention provide~s a heating unit for hot water heating sys~ems
comprising: a heat exchanger to be heated by the hot exhaust gases of a heat-
ing combustion system, an equalizing vessel connected in series with the heat
exchanger, whereby an independent, closed heating system is formed by the
series connection of heat exchanger, equalizing vessel and a plurality of
heat radiators, said equalizing vessel having an additional inlet through
which return water from the heat radiators is passed directly to the equaliz-
ing vessel, bypassing the heat exchanger 16.
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According to the invention the thermal energy of the hot exhaust
gases of a conventional room-heating combustion system ls utilized by an
additional heating unit which abstracts heat from the hot exhaust gases via
the heat exchanger. The supplementary heating unit operates a hot water
room heating system with its own pipe system and its own heat radiators,
completely separate of the remaining heating system. The equalizing vessel
functions as a vessel for making available an adequate reserve of hot water
for this separate heating system.
Considerations of construction on the one hand and considerations
of heat technology on the other hand define the arrangement of the heat
exchanger. For example, the heat exchanger advantageously comprises a copper
tube coil, can project into the combustion chamber of the firing system or
into the exhaust gas pipe so that it is in contact all round with the hot
combustion gases. This results on the one hand in good thermal transfer from
the hot gases to the heat exchanger but on the other hand this system is less
suited for subsequent installation and it is also possible for the heat
exchanger to detrimentally reduce the cross-section of the exhaust gas pipe.
If the heat exchanger is mounted on the external circumference of
the exhaust gas pipe, more particularly as a copper tube coil which is wound
in helical configuration on the exhaust gas pipe, the flow cross-section
thereof will not be reduced and subsequent attachment ~o an existing heating
system is possible without difficulty. If the copper tube is also addition-
ally soldered to the exhaust gas pipe this will also provide a very good
thermal transfer from the exhaust gas pipe ~o the heat exchanger to permit
good utilization of the heat energy contained in the exhaust gases.
This embodiment also offers the advantage that the heating unit
according to the invention can be supplied by the manufacturer in completely
prefabricated form. To this end the heat exchanger and, where appropriate,
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the equalizing vessel, is supplied already fixedly mounted on a pipe section
and to install the heating unit it is merely necessary to replace a corre-
sponding portion of the exhaust gas pipe by the pipe portion which is pro-
vided with the heat exchanger.
The water which is heated in the heat exchanger is collected in
the equalizing vessel and passes from there by gravity or by means of a
pump through the pipe system to the heat radiators. Advantageously the
equalizing vessel also bears upon the exhaust gas pipe so that this can also
transfer heat into the equalizing vessel to prevent any reduction in the
temperature of the water. The cooled return water from the heat radiators
passes again into the equalizing vessel after being heated by the heat
exchanger. The duct which bypasses the heat exchanger and enables the cooled
return water to be conducted directly into the equalizing vessel, after being
metered by means of a valve enables the equalizing vessel to be used as mixing
vessel for adjusting the temperature of the heated water for the heat radi-
ators.
In another embodiment of the invention the heat exchanger comprises
a vessel through which the water of the room heating system flows and through
which extend several heat pipes which conduct the exhaust gases of the room
heating firing system.
This embodiment is also ideally suited for subsequent installation
into an existing heating system in the manner already described above. The
heat exchanger is of exceptionally simple construction because an inexpensive-
ly constructed vessel is used to contain the water which is to be heated.
An adequate area of contact for heat transfer is provided because the hot
exhaust gases of the combustion system are conducted in a plurality of heat
pipes through the water in the vessel.
The heat exchanger is particularly simple if the heat pipes extend
rectilinearly through the water container. To this end it is advantageous
to provide at least four heat pipes so as to ensure an adequately large area
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of contact between the heat pipes and the water that is to be heated, even
if the heat pipes extend rectilinearly.
The heat exchanger can be insertable into the exhaust gas pipe
of the room-heating combustion system and can be provided with an inlet
socket which can be connected to the exhaust gas pipe and branches into the
heat pipes and can also have an exit socket which can be connected to the
exhaust gas pipe and in which said exit socket the heat pipes are combined.
In a further development of this embodiment the heat exchanger
can be placed on the combustion chamber of a room-heating combustion system
and the exhaust gases of the firing system can directly enter the heat pipes
which are combined in an exit socket that can be connected to the exhaust
gas pipe.
This embodiment leads to particularly compact external dimensions
because the heating unit according to the invention directly adjoins the
combustion chamber of the firing system.
Particularly good heat utilization is also achieved since the
water container of the heating unit is in direct thermal contact with one
wall of the combustion chamber of the firing system.
An additional equalizing vessel is not necessary in many cases
since the water container of the heat exchanger is able to hold a relatively
large volume of water and instead the water container itself can also func-
tion simultaneously as equalizing vessel which makes available an adequate
quantity of water for the heat radiators that are to be supplied. However,
it is a disadvantage that the entire return water of the space heating
system flows via the heat exchanger so that it is not possible for part of
the cold return water to be fed directly via a mixing valve to the equal-
izing vessel, while bypassing the heat exchanger, in order to adjust the
temperature of the feed water which is supplied to the room-heating system.
The heating unit according to the invention can be employed in
conjunction with any conventional room-heating combustion system. If the
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heating unit is attached to the exhaust gas pipe of the boiler combustion
system of a combination heating system it is possible for such a post-
heating unit to supply between two and three heat radiators of average size.
Tests have shown that in this wav it is possible to properly heat a room
area of 40 to 45 m at normal room height. If the heating unit according
to the invention is already planned when the conventional heating system is
installed it is possible for the latter to be constructed with corre-
spondingly smaller dimensions. If on the other hand the heating unit accord-
ing to the invention is only subsequently installed it is possible for the
heat-rating of the conventional system to be reduced. A saving of approx-
imately 15 to 30% of the heating costs is possible in each case as has been
shown by tests. Subsequent installation of the heating unit according to
the invention is also exceptionally simple. This merely calls for the
removal in the above-described manner of part of the exhaust gas pipe of
the existing room-heating system and the insertion of the corresponding
pipe section with a heat exchanger and the equalizing vessel. The heat and
return pipes of the two to three heat radiators which are to be supplied
by the heating unit according to the invention are separated from the ex-
isting room-heating circulation and are connected to the heating unit ac-
cording to the invention.
The heating unit according to the invention can also be used inan exceptionally advantageous manner in conjunction with an individual
heating system for heating a flat on one floor. To this end a coal, oil
or gas furnace is arranged so that it simultaneously and directly heats two
or three adjoining rooms. Such a furnace is provided with a heating unit
according to the invention the heat exchanger of which surrounds the exhaust
gas pipe of the furnace and can also be mounted on said furnace. The heat
exchanger can of course also be disposed in the combustion chamber of the
furnace. Such a heating unit supplies the hot water heat radiators which
are provided in the rooms that do not adjoin the furnace. In this way it
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is possible for three to four rooms, each having a size of approximately
15 to 18m , to be heated in addition to the two to three rooms which are
directly heated by the furnace. This combination of a furnace which direct-
ly heats two to three rooms by radiation heat and a heating unit which
supplies the remaining rooms with hot water heating permits an entire flat
on one floor to be heated from a single fireplace. The embodiment of the
heating unit in which the heat exchanger is mounted directly on the com-
bustion chamber of the furnace is particularly suitable for this application
because of the compact construction.
Installing this kind of heating for a flat on one floor is
substantially simpler and less expensive than conventional kinds of heating
for flats on one floor. Moreover, optimum utilization of the exhaust gas
heat also achieves a substantial reduction of heating costs. Finally, it
is possible in this way to combine the advantages of hot water heating with
those of furnace heating. It is frequently sufficient, particularly during
the spring and autumn season, to fire a furnace for only brief periods which
results in rapid heating by radiation heat of the rooms which are heated by
such a furnace. Such rapid brief heating-up is not possible with conven-
tional hot water room heating systems.
Embodiments of the invention will now be explained, by way of
example only, with reference to the accompanying drawings, in which:
Figure 1 is a heating unit according to the invention attached to
the combustion system of a central heating system;
Figure 2 shows a second embodiment of the heating unit attached
to the combustion system of an individual heating system;
Figure 3 shows in diagrammatic form the means of heating an apart-
ment by means of heating units according to the invention;
Figure 4 shows a third embodiment of heating unit; and
Figure 5 shows a fourth embodiment of heating unit.
The use of a heating unit in conjunction with the boiler firing
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system of a central heating system is illustrated in diagrammatic form in
Figure 1.
The numeral 10 refers to the combustion chamber of a conventional
combination heating system, for example fired by means of an oil burner 12.
The hot exhaust gases of the combustion system discharge through an exhaust
gas pipe 14. The heat medium boiler and the pipelines of this conventional
central room--heating system are not shown in the drawing.
An additional heating unit is attached to the exhaust gas pipe
14 and comprises a heat exchanger in the form of a copper tube 16 wound
helically around the exhaust gas pipe 14, and an equalizing vessel 18. The
copper tube 16 is soldered to the surface of the exhaust gas pipe 14 in
order to provide good therrnal contact. Advantageously the copper pipe 16
is mounted on a separate portion of the exhaust gas pipe 14 50 that the
heating unit can also be subsequently installed in a simple manner in an
existing room heating system.
The equalizing vessel 18 is a half`-shell of semi-cylindrical
form and bears upon the exhaust gas pipe 14.
The heat exchanger 16 and the equalizing vessel 18 are connected
in series in a totally enclosed pipe system of a hot water room-heating
system. The pipe system comprises a feed pipe 20 which extends from the
equalizing vessel 18 and can also incorporate a circulating pump 22 when
necessary. Two hot water radiators 24 are fed by the feed pipe 20. A
return pipe 26 extends to the heat exchanger 16. The hot water pipe system
is also provided in conventional manner with an expansion vessel 28, a
pressure gauge 30, a safety valve 32 and a drain cock 34.
The return water can be conducted directly from the return pipe
26 via an additional inlet 36 into the equalizing vessel 18 bypassing the
heat exchanger 16. A mixer valve, not shown, permits metering of the cold
return water which is introduced directly via the inlet socke-t 36 into the
equalizing vessel 18.
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The equalizing vessel 18 is also provided with an inlet, not
shown, which permits the addition of fresh water for topping up the pipeline
system.
The method of operation of the heating unit is as follows:
The hot exhaust gases of the combustion system 10 passing through
the exhaust gas pipe 14 to a chimney, heat the water in the heat exchanger
]6. The heated water passes into the equalizing vessel 18 which also func-
tions as a storage vessel for the pipeline system. Contact between the
equalizing vessel 18 and the exhaust gas pipe 14 prevents the water in the
equalizing vessel 18 from cooling. The equalizing vessel 18 feeds the heat
radiators 24 via the feed pipe 20. The water, cooled in the heat radiators
24, returns via the return pipe to the heat exchanger 16 where it is again
heated. Part of the cooled return water can be supplied in metered form
directly to the equalizing vessel 18 via the inlet 36 for the purpose of
adJusting the temperature of the feed water. The water in the pipeline
SyBtem can be circulated by gravity or by means of the pump 22.
Figure 2 shows another example of the heating unit. To the ex-
tent to which the details of the system illustrated in Figure 2 correspond
to those illustrated in Figure l they have the same referer.ce symbols and
reference should be made to the description relating to Figure 1.
The important difference of the system illustrated in Figure 2
with respect to that shown in Figure l is that the heating unit is not
attached -to the combustion sys-tem of a conventional central room-heating
system but is attached to the combustion system of an individual space
heating system. The individual heating system comprises a heater insert
38 which is fired ~y an oil or gas burner. Coal-firing of the insert 38
is of course also possible. The heat exchanger 16 of the heating unit is
directly inserted into the heater inser-t 38. The heat exchanger 16 is
therefore in direct contact with the hot combustion gases in the heater
insert.
, .
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The heater insert 38 is used for directly heating rooms,
predominantly by radiation. With the exception of the inserted heat ex-
changer 16 the heater insert 38 can correspond substantially to convention-
al individual furnaces. Advantageously the insert is provided with cladding,
for example in mesh form, to permit unobstructed passage of the radiation
heat and to prevent contact with the hot surface of the insert. Cladding
of wrought iron bars can also be selected in place of a steel plate in mesh
form. The insert can also be provided with a heat-storing cladding, such
as tiles or the like.
The heat exchanger 16 need not of course be mounted directly in
the combustion chamber of such a heating insert 38. The heat exchanger 16
can surround the exhaust gas pipe 14 of the heater insert 38 in the marmer
described in Figure l.
Since the heater insert 38 heats the surrounding space mainly by
laterally radiated heæt it is also possible to mount the heat exchanger of
the heating unit directly on the top surface of the heater insert 38.
Figure 3 illustrates an example of heating an apartment in opti-
mum manner by using the heating unit according to the invention. It makes
use of a heater insert 38 which stands on the floor 42 of the apartment.
20 The insert extends into two rooms, for example a living room 44 and a nur-
sery 46. The two rooms 44 and 46 as well as the floor 42 are thus directly
heated by the insert 38 through radiation heat. The remaining rooms of the
flat are heated by hot water heating obtained from heating units according
to the invention. Two such heating units are provided in the example il-
lustrated in Figure 3. The heat exchanger 16 of one heating unit can be
mounted in the interior of the combustion chamber of the heater insert 38,
as illustrated in Figure 2. This heating unit can supply the heat radiators
24 of two further bedrooms 48. The heat exchanger 16 of the second heating
unit can for example surround the exhaust gas pipe 14 as illustrated in
30 Figure 1 or it can be mounted on the top surface of the heater insert 38.
,
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The second heating unit can heat the heat radiators 24 of the remaining
rooms, for example bedroom 50, dining room 52 and kitchen 54.
In this way it is possible for the entire apartment as illustrated
in Figure 3 to be heated by a single heating system which can also be fired
from the floor.
In the embodiment illustrated in Figure 4 a heat exchanger in the
form of a compact structural unit is inserted into the exhaust gas pipe 14.
The heat exchanger has an inlet socket 56 which is connected to the exhaust
gas pipe 14. The inlet socket 56 branches into at least four heat pipes 58
which extend in parallel rectilinear manner in the upward direction where
they again merge into a common exit socket 60. The extension of the exhaust
gas pipe 14 adjoins the exit socket 60. The heat pipes 58 are surrounded by
a vessel which is filled with ~he water of the room-heating system so that the
water is in all-round contact with the heat pipes 58.
The vessel 58 is connected through a bottom connector 26 to the
return pipe of the heat radiators which are to be supplied thereby. A top
connector 20 leads to an equalizing vessel (not shown) to which is connected
the feed pipe of the heat radiators to be supplied thereby, or leads direct-
ly to the feed pipe if no equalizing vessel is provided.
Figure 5 shows a fourth embodiment of the heating unit. In this
embodiment the vessel 62 is mounted directly on the combustion chamber 10
of the combustion system and foTms its top wall. The rectilinear, vertical-
ly extending heat pipes 58 emerge directlr from the combustion chamber 10,
extend through the vessel 62 and at the top end thereof extend into a com-
mon exit socket 60 which adjoins the exhaust gas pipe 14.
By contrast to the embodiment illustrated in Figure 4 the water
in the embodiment accord~ng to Figure 5 is heated in the vessel 62 not only
by the hot exhaust gas which flows through the heat pipes but also by the
hot combustion gases in the combustion chamber 10 which are in contact with
the bottom wa]l of the vessel 62.
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As shown in the drawing, the embodiment of Figure ~ is partic-
ularly suited for addition as a modification in an existing room-heating
system because the heat exchanger can be readily fitted into the exhaust
gas pipe of the existing combustion system. The embodiment of Fi.gure 5 on
the other hand leads to a substantially more compact construction of the
arrangement comprising the combustion system and the heating unit so that
this embodiment is particularly suitable f'or room-heating systems for
apartmentsand the like in which the combustion system and the heating unit
are visibly housed in the rooms which are to be heated.
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