[0001] Method to control the flow rate and of a heat exchanging fluid medium to a riser
in a one-pipe system being a typical pipe set up in for example building cooperatives
for supplying heat to the radiators of the flats. The method being to regulate the
temperature of the supplied heat exchanging fluid medium in response to changes in
external parameters (temperature) and the flow rate in response to the temperature
of the heat exchanging fluid medium in an return line.
BACKGROUND
[0002] Typical set ups of the pipes supplying radiators in e.g. housings or building cooperatives
are either two-pipe systems or one-pipe systems. In the following there shall be referred
in general to 'houses' meaning housings comprising a plural of flats, or any other
places where such setups are typical.
[0003] In traditional two-pipe systems a set of parallel pipes forms supply pipes (or 'lines'
in more general) and return pipes (or 'lines') to a collection of heat exchanging
devices such as radiators. The pipes associated with each such collection of heat
exchanging devices is referred to as risers, and in two-pipe systems the flow rates
at each riser are in traditional systems regulated individually, thus giving dynamic
flow rates in each riser matching the present loads.
[0004] In one-pipe systems, however, the supply line system feeds some heat exchanging fluid
medium (typically water) and a supply temperature (typically water) at a flow rate
to a collection of heat exchanging devices. The individual radiators are connected
in series with one after the other, such that the return line of one radiator is the
feeding line of a next radiator.
[0005] The flow rates of the heat exchanging fluid medium to each radiator are usually controlled
by thermostats being set by the users of the radiators, but the overall flow in the
supply and return lines is in traditional systems substantially permanent, meaning
it is not reacting to changes in the load.
[0006] For example on a hot day , or simply when internal gains in the room cause the radiator
thermostat to close, the radiator thermostats in general is closed letting most of
the heat exchanging fluid medium flow through the bypass lines, such a setup leads
to an undesired high temperature of the heat exchanging fluid medium in the return
line(s). A high temperature of the return heat exchanging fluid medium is not desired,
since it leads to an uncontrolled heating of the living spaces and further to unnecessary
losses of heat of the heat exchanging fluid medium in the lines, since the lines will
continue to deliver heat though, the radiators are closed. This is especially the
case where the lines are not well insulated. This would be a further discomfort to
the inhabitants.
[0007] In two-pipe systems the valve actuator regulating the flow is placed centrally. This
is not possible in a one-pipe-system, since it will cause underflow in parts of the
system still having high load, and overflow in parts / risers with low load.
[0008] The present invention relates to introducing a solution giving a highly energy-efficient
and load dependent one-pipe system.
SUMMARY OF THE INVENTION
[0009] The present invention solves the problems of one-pipe systems by introducing a two-part
control, one being to regulate, or control, the temperature of the supplied heat exchanging
fluid medium, the supply temperature, and another to control flow through a collection
of heat exchanging devices in relation to the temperature of the heat exchanging fluid
medium in the return line. The control of flow and return temperature is done "de-centrally"
in each riser.
[0010] The supply temperature control is based on external conditions comprising conditions
influencing the system that cannot be influenced by the system itself, this preferably
includes, for example, the weather by introducing a weather compensator (more especially
the external temperature, being e.g. the outdoor temperature of a housing), but could
also include other factors that would influence the expected needed heat to be supplied
to the houses. The main, but not exclusive, embodiment is especially related to the
external temperature, the system thus optionally including an external temperature
sensor. In an even more advanced embodiment the system is coupled to a weather forecast
system such as through the internet.
[0011] The present invention thus introduces a method of regulating a system according to
claim 1.
[0012] To ensure an optimized set point of the system, the supply temperature is regulated
according to a supply set point temperature depending on parameters external to the
system, and the flow rate is regulated according to a return set point temperature
depending on a temperature of the heat exchanging fluid medium downstream of the first
heat exchanging device in the collection. The return set point temperature is regulated
in response to a regulation of the supply set point temperature.
[0013] To ensure that the system comprises the means to perform the regulation of the flow
in relation to the temperature of the heat exchanging medium in the return line, the
method in a further embodiment applies to a system further comprising
- a flow controller connected to a return line, the flow controller being adapted to
control the flow rate through the return line,
- an actuating device operating the flow controller, and
- a temperature sensor positioned in heat exchanging connection to the heat exchanging
fluid in the return line.
[0014] To ensure a permanent flow despite frequent changes in the loads to each of the heat
exchanging devices, e.g. as they are adjusted by the users, the flow controller is
further adapted to maintain a constant flow despite changes in the pressure in the
main supply line.
[0015] To avoid feeding unnecessarily much energy into the system by rather meeting external
conditions in advance, the system in one embodiment may comprise an external temperature
sensor positioned to measure a temperature external to the system.
[0016] Especially, but not exclusively, to ensure regulation of the return temperature at
set point depending on different parameters, the system in one embodiment may comprise
an electronic controller connected to the actuating devices and the temperature sensors
connected to the return lines. The electronic controller is optionally connected to
a temperature sensor connected to the main supply line, and optionally also to the
external temperature sensor.
[0017] In one embodiment the actuating device is pulse actuated, such as where the actuating
device is an electro-magnetic, pneumatic, hydraulic or electrostrictive actuator.
[0018] To ensure an optimized set point of the system, in an embodiment the supply temperature
is regulated according to a supply set point temperature depending on parameters external
to the system, and the flow rate is regulated according to a return set point temperature
depending on a temperature of the heat exchanging fluid medium downstream of the first
heat exchanging device in the collection. The return set point temperature is preferably
regulated in response to a regulation of the supply set point temperature.
[0019] In an alternative embodiment to the electronic controller, the actuating devices
are connected directly to the temperature sensors and are self-acting and include
means to adjust the return temperature set point. A natural choice is that the actuating
device is a thermostat.
FIGURES
[0020]
- Fig. 1
- Illustration of a standard one-pipe, or one-line, set up whereto the present invention
would be suitable.
- Fig. 2
- Illustration of a number of parallel risers each associated with a collection of heat
exchanging devices, and where each riser is controlled according to one embodiment
of the present invention.
- Fig. 3
- Illustration of a flow controller used in one embodiment of the present invention,
the flow controller being adapted to maintain a constant flow despite pressure changes.
- Fig. 4
- Illustration of set point dependences on external conditions.
- Figs. 5A and 5B.
- Illustrations of how the present invention relates the flow rate to better match the
actual load in the system.
- Fig. 6.
- Illustration of the system introducing an electronic controller according to an embodiment
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Fig. 1 illustrates a typical set up of a one-pipe system, where a supply line (3)
system feeds some heat exchanging fluid medium (typically water) at a supply temperature
and at a flow rate, to a collection of heat exchanging devices (6), such as e.g. radiators,
and adapted to heating up a number of living spaces. In the following, with out loss
of generality, such heat exchanging devices (6) are frequently referred to as radiators.
The individual radiators (6) are connected in series, one after the other, such that
the return line (4) of one radiator (6) is the feeding line (3) of a next radiator
(6). The feeding line (3) and return line (4) of each radiator (6) is additionally
connected by a bypass line (5). A main supply line (1) is connected to the feeding
line (3) of the first of the radiators (6) in the collection, seen in the flow direction,
and a main return line (2) is connected to the return line (4) of last of the radiators
(6) in the collection, seen in the flow direction.
[0022] Such a setup is in some places typical in houses comprising a number of rooms and
flats, where e.g. a number of parallel risers are each connected to a number rooms
/ flats. In this text each of these rooms / flats is regarded as one heat exchanging
device, the rooms / flats associated with a riser then comprising a 'collection' of
heat exchanging devices, or radiators (6).
[0023] The individual radiators (6) within each room / flat may be connected according to
a similar or a very different setup.
[0024] In houses comprising a plural of risers the system thus comprises a corresponding
plural of collections of radiators in series and connected to the common main supply
line (1) and the main return line (2), the flow through each of the collections being
regulated individually.
[0025] The heat exchanging medium may be supplied directly to the radiators (6) (in the
following referred to as the direct supply setup), or the system may introduce a substation
comprising a heat exchanger separating the supplier lines from e.g. a house (in the
following referred to as the substation setup), thus forming a closed loop for the
heat exchanging fluid to circulate to the individual radiators (6). The flow rates
of the heat exchanging fluid medium to each radiator (6) are controlled by flow regulating
means (7), in the following being, without loss of generality, referred to as a the
radiator thermostats.
[0026] The regulation of the flow rates to the radiators (6) in addition influences the
flow in the bypass lines (5), by changing the flow to the radiators (6), the flow
through the bypass lines (5) being changed accordingly.
[0027] On for example a hot day, or just when internal gains in the room cause the radiator
thermostat (7) to close, the radiator thermostats (7) in general being closed to let
most of the heat exchanging fluid medium flow through the bypass lines (5), such a
setup leads to an undesired high temperature of the heat exchanging fluid medium in
the return line(s) (4). A high temperature of the return heat exchanging fluid medium
is not desired, since it leads to an uncontrolled heating of the living spaces and
further to un-necessary losses of heat of the heat exchanging fluid medium in the
lines, since the lines will continue to deliver heat though the radiators are closed.
This is especially the case where the lines are not well insulated. This would be
a further discomfort to the inhabitants.
[0028] The present invention solves this problem by introducing a two part control, one
being to regulate, or control, the temperature of the supplied heat exchanging fluid
medium, the supply temperature, and another to control the flow through a collection
of heat exchanging devices (6) in relation to the temperature of the heat exchanging
fluid medium in a return line (3).
[0029] The supply temperature control is based on external conditions comprising conditions
influencing the system that cannot be influenced by the system itself, this preferably
includes such as the weather (more especially the external temperature, being e.g.
the outdoor temperature of a housing), by introducing a weather compensator, but could
also include other factors that would influence the expected needed heat to be supplied
to the houses. The main, but not exclusive, embodiment is especially related to the
external temperature, the system thus optionally including an external temperature
sensor (8). In an even more advanced embodiment the system is coupled to a weather
forecast system such as through the internet.
[0030] The regulation of the flow to the risers in this manner are based on the actual demand(s),
or load (2), in the riser(s), in that a changing demand changes the temperature of
the heat exchanging fluid medium in the return line(s) (4).
[0031] Fig. 2 illustrates a set up according to the present invention, where a flow controller
(9) is connected to a return line (4) associated with a collection of radiators (6)
for controlling the flow of heat exchanging fluid in the lines supplying these radiators)6).
[0032] The flow controller (9) in one preferred but not limiting embodiment has two operations
in that both a flow control valve and a pressure independent balancing valve. The
flow controller (9) in this embodiment includes means to set a desired flow rate,
and means to ensure this substantially constant flow rate despite pressure changes
in the flow system. Such valves are available in the market, where examples are the
AB-QM product series provided by Danfoss A/S, and disclosed in e.g. the patent
DE 103 23 981.
[0033] Fig. 3 illustrates such a valve (9), or flow controller, consisting of two parts,
a differential pressure controller and a control valve. The differential pressure
controller maintains a constant differential pressure across the control valve (9).
The control valve (9) comprises a spindle (31), stuffing box (32), plastic ring (33),
control valve's cone (34), membrane (35), main spring (36), hollow cone (pressure
controller) (37) and vulcanized seat (pressure controller) (38). The pressure difference
ΔPcv (P2 - P3) on the membrane (35) is balanced with the force of the spring (36).
Whenever the differential pressure across the control valve (9) changes (due to a
change in available pressure, or movement of the control valve) the hollow cone (37)
is displaced to a new position that brings a new equilibrium and therefore keeps the
differential pressure at a constant level. The control valve (9) has a linear characteristic.
It features a stroke limitation function that allows adjustment of the Kv value. The
stroke limitation is changed by lifting the blocking mechanism and turning the top
of the valve (9) to the desired position. A blocking mechanism automatically prevents
unwanted changing of the setting.
[0034] Introducing such a flow controller (9) has one further advantage, in that, for example,
the flow in the risers is regulated / controlled mutually independently, despite being
connected to common main supply (1) and return (2) lines.
[0035] Returning to Fig. 2, the figure shows the flow controller attached to the return
line (4) of the last of the radiators (6) seen in the direction of flow, an actuating
device (10) being connected to the flow controller (9), optionally by the use of an
adapter. Further seen is a temperature sensor (11) adapted to be positioned in thermal
exchange connection to the return line (4).
[0036] The actuating devices (10) may be actuators, and may be self-acting or controlled,
and operating in any manner as known in the arts, such as electro-magnetic, pneumatic,
hydraulic, electroactive etc.
[0037] Fig. 2 thus shows a system where the control is based on two parts, one being related
to regulating the supply temperature in dependence of external conditions, such as
the external temperature, the second being to regulate the flow associated with each
collection of heat exchangers (6), in dependence of the return temperature, the temperature
of the heat exchanging fluid medium in a return line (4). The system thereby becomes
a variable flow system with individual flow control for each riser depending on the
load on each of the individual risers.
[0038] Fig. 4 shows two curves illustrating the regulation according to the present invention.
The upper curve (12) illustrates a regulation dependence of the supply temperature
to the external temperature. Or at least illustrates how a set point of the supply
temperature changes with changing external temperature. The exact curve and dependence
would depend on a number of factors, such as e.g. the state of insulation of the housing,
and would typically be optimized to the conditions of the actual system.
[0039] It is an advantage to change the temperature set point of the return temperature
according to the changing of the set point of the supply temperature for several reasons,
such as problems caused by excess heat.
[0040] In the same manner the lower line (13) therefore illustrates a dependence of the
regulation of the return temperature set point, the curve being an update of basic
return temperature control where the return temperature set point actively follows
the result of the control of the supply temperature based on the external temperature.
It is therefore a control of the set point of the return temperature. The aim is that
the performance of control where flow is adjusted to load in each riser remains perfect
throughout the heating season.
[0041] The lower curve (13) thus changes based on two factors, supply temperature and load
in riser(s), as the load in the risers is unpredictable and changes from 100% to 0%,.
[0042] The system of the present invention thus introduces a 'super' control being the control
of the supply temperature set point in relation to external conditions, and a 'sub'
control correcting the system by changing the flow according to the return temperature,
being related to the load in the riser(s), and where the set point of the return temperature
in embodiments of the present invention actively changes according to the change of
the set point of the supply temperature.
[0043] Fig 5A shows a graphic representation of flow to load relation in a traditional one-pipe
system without any regulation according to the present invention, where the dashed
line (14) illustrates the actual flow rate fluctuating unpredictably since these systems
are dynamic due to the radiator thermostat (7) actions. The wavy line (16) is the
actual load clearly seen to be uncorrelated to the actual flow rate.
[0044] The straight line (15) is caused by the introduction of the pressure independent
flow controller (9) according to the present invention.
[0045] Fig. 5B shows the situation according to the present invention, where the flow is
controlled in dependence of the return temperature, thus controlling the flow according
to the demand, or load. This gives a flow rate (17) much more matching the actual
demand, and thus giving a much more efficient system.
[0046] The illustrated system in Fig. 2 shows a simple setup of the present invention, where
the actuating device (10) operating flow rate setting of the flow controller (9) is
a thermostat of any kind as known in the arts, the system thus being self acting.
The temperature sensor (11) being directly connected to the actuating device (10).
[0047] Such a setup has the advantage of not needing any additional energy source for operation,
and each riser may be regulated individually. Using a standard thermostat as actuating
device (10) as known in the arts, further gives the advantages that such devices often
include means to set a temperature set point, the set point of the return temperature
therefore being adjustable according to a dependence as, for example, illustrated
in Fig. 4.
[0048] Fig. 6 shows an embodiment where all sensors (8), (9) and (19) (temperature sensor
measuring the temperature of the heat exchanging medium in the main supply line (1))
and flow controllers (9), or alternatively the actuating devices (10) are connected
to an electronic controller (18) adapted to individually regulate the flows in response
to the measured temperatures. Introducing such an electronic controller (18) gives
a number of advantages in relation to the self acting actuating device.
[0049] The electronic controller (18) comprises the needed means for electronic controllers
(18) as they are well known in the arts of electronic controllers.
[0050] The set point of the return temperature is automatically adjustable according to
the actual conditions by the electronic controller (18), whereas in the self-acting
embodiment the set point of the return temperature is usually set manually. This gives
a huge potential in saving energy, since the system would optimize the set point of
the return temperature according to an optimized curve (13) as illustrated in Fig
4.
[0051] In this electronic version principle, the supply temperature is controlled by the
external temperature measurement (the 'super control'). Based on these 'super'-control
actions the return temperature set point is controlled to appropriate setting that
makes it possible to optimize the system performance throughout the year, the performance
therefore not depending on system load (outside temperature). The 'sub'-controls of
the flows in the risers is related to the individual collection of radiators (6) /
riser loads, and thus correlates flow to heat demand, and thereby converts this one-pipe
system from a traditional constant flow system into a highly energy efficient variable
flow system.
[0052] Another advantage is that the electronic controller (18) allows monitoring and registering
temperatures and flows for control and system monitoring, in order to actively optimise
the system parameters over time.
[0053] For protection of the pump of the system, in the case that all risers are dosed,
the electronic controller (18) may in one embodiment automatically open valves / flow
controllers (9) located in at least one of the risers to ensure minimum flow.
[0054] The illustrated system comprises an external temperature sensor (8) for measuring
outdoor temperature. The regulation of the supply temperature in the main supply line
(1) may be done in any manner as it would be obvious according to the actual set up.
In the illustrated substation setup system this could be by regulating the primary
flow of fluid to the primary side of the heat exchanger (20) of the substation.
[0055] The electronic controller (18) is connected to the individual actuating devices (10),
and is adapted to induce an actuation. In one embodiment the state of the actuating
devices (10) is further registered by the electronic controller (18).
[0056] The electronic controller (18) is further connected to the temperature sensors (9)
(19) measuring the supply temperature of the main supply line (1) and the return of
the individual risers. Optionally it could also be connected to the external condition
/ temperature sensor (8).
[0057] In one embodiment, the actuating device (10) attached to the flow controller (9)
is pulse actuated. Pulse width modulation as mean of control uses pulses at some frequency
to modulate control the flow precisely. The actuating device (10) is adapted to slowly
close or open the flow controller (9) in that it closes off or opens for the flow
in the riser, a pulse making the actuating device (9) open or close a little for the
flow. The frequency of the pulses then defines the opening status of the flow controller
(9). The more frequent the pulses, the more open a flow controller (9) or alternatively
the more closed a flow controller (9). The situation where the pulses make the actuating
member (10) close the flow controller (9) is preferred since, in the case of a failure
of the system, there would still be a flow, but the present invention is not limited
to this.
1. Method of regulating a system comprising;
- a collection of heat exchanging devices (6) connected in series, such that a return
line (4) of one heat exchanging device (6) is a feeding line (3) of a next heat exchanging
device (6),
- a main supply line (1) connected to the feeding line (3) of a first of the heat
exchanging devices (6) seen in the flow direction,
- a main return line (2) connected to the return line (3) of the last of the heat
exchanging devices (6) seen in the flow direction,
where a heat exchanging fluid medium with a supply temperature is fed from the main
supply line (1) to the collection of heat exchanging devices (6) at a flow rate, wherein
the flow rate is regulated according to a return set point temperature depending on
a temperature of the heat exchanging fluid medium downstream of the first heat exchanging
device (6) in the collection,
characterised in that the supply temperature is regulated according to a supply set point temperature depending
of parameters external to the system,
wherein the return set point temperature is regulated in response to a regulation
of the supply set point temperature.
2. Method according to claim 1, wherein the flow rate is regulated according to a set
point temperature of the return temperature of the heat exchanging fluid medium after
the last of the heat exchanging devices (6) seen in the flow direction.
3. Method according to claim 1 or 2, wherein the supply set point temperature is regulated
in dependence of an external temperature to the system.
4. Method according to any of the preceding claims, wherein the system further comprises
- a flow controller (9) connected to a return line (4), the flow controller (9) being
adapted to control the flow rate through the return line (4),
- an actuating device (10) operating the flow controller (9), and
- a temperature sensor (11) positioned in a heat exchanging connection to the heat
exchanging fluid in the return line (4).
5. Method according to claim 4, wherein each flow controller (9) is further adapted to
maintain a constant flow despite changes in the pressure in the main supply line (1).
6. Method according to one of claims 4 or 5, wherein an external temperature sensor (8)
is positioned to measure a temperature external to the system.
7. Method according to claim 6, wherein an electronic controller (18) is connected to
each actuating devices (10) and the temperature sensor (11) is connected to the return
line (4) of the heat exchanging device (6) where it is positioned in heat-exchange
connection.
8. Method according to claim 7, wherein the electronic controller is connected to a temperature
sensor (19) connected to the main supply line (1).
9. Method according to one of claims 7 or 8, wherein each actuating device is pulse actuated.
10. Method according to claim 9, wherein at least one actuating device (10) is an electro-magnetic,
pneumatic, hydraulic or electrostrictive actuator.
11. Method according to claim 4 or 5, wherein each actuating device (10) is connected
directly to a temperature sensor (11) and is self-acting and includes means to adjust
the return temperature set point and where the actuating device (10) is a thermostat.
12. Method according to any preceding claim, wherein the feeding line and return line
(4) of each heat exchanging device (6) are additionally connected by a bypass line
(5).
1. Verfahren zum Regulieren eines Systems, das umfasst:
- eine Sammlung von Wärmetauschervorrichtungen (6), die in Reihe miteinander derart
verbunden sind, dass eine Rückführungsleitung (4) von einer Wärmetauschervorrichtung
(6) eine Zufuhrleitung (3) einer nächst folgenden Wärmetauschervorrichtung (6) ist,
- eine Hauptzufuhrleitung (1), die mit der Zufuhrleitung (3) einer ersten der Wärmetauschervorrichtungen
(6) verbunden ist, wobei der Verbindungsfluss in Strömungsrichtung betrachtet ist,
- eine Hauptrückführungsleitung (2), die mit der Rückführungsleitung (3) der letzten
der Wärmetauschervorrichtungen (6) verbunden ist, wobei der Verbindungsfluss in Strömungsrichtung
betrachtet ist,
wobei ein Wärmetauschfluidmedium mit einer Zufuhrtemperatur von der Hauptzufuhrleitung
(1) zu der Sammlung von Wärmetauschervorrichtungen (6) mit einer Durchflussmenge zugeführt
wird, wobei die Durchflussmenge gemäß einer Sollwerttemperatur für die Rückführung
in Abhängigkeit von einer Temperatur des Wärmetauschfluidmediums stromabwärts der
ersten Wärmetauschervorrichtung (6) in der Sammlung reguliert wird,
dadurch gekennzeichnet, dass die Zufuhrtemperatur gemäß einer Sollwerttemperatur für die Zufuhr in Abhängigkeit
von Parametern außerhalb des Systems reguliert wird,
wobei die Sollwerttemperatur für die Rückführung als Reaktion auf eine Regulierung
der Sollwerttemperatur für die Zufuhr reguliert wird.
2. Verfahren nach Anspruch 1, wobei die Durchflussmenge gemäß einer Sollwerttemperatur
der Rückführungstemperatur des Wärmetauschfluidmediums nach dem letzten der Wärmetauschervorrichtungen
(6) reguliert wird, wobei der Verbindungsfluss in Strömungsrichtung betrachtet ist.
3. Verfahren nach Anspruch 1 oder 2, wobei die Sollwerttemperatur für die Zufuhr in Abhängigkeit
von einer Temperatur außerhalb des Systems reguliert wird.
4. Verfahren nach einem der vorhergehenden Ansprüche, wobei das System ferner umfasst:
- eine Durchflusssteuereinheit (9), die mit einer Rückführungsleitung (4) verbunden
ist, wobei die Durchflusssteuereinheit (9) dafür ausgelegt ist, um die Durchflussmenge
durch die Rückführungsleitung (4) zu steuern,
- eine Betätigungsvorrichtung (10), die die Durchflusssteuereinheit (9) betreibt,
und
- einen Temperatursensor (11), der in einer Wärmeaustauschverbindung mit dem Wärmetauschfluid
in der Rückführungsleitung (4) positioniert ist.
5. Verfahren nach Anspruch 4, wobei jede Durchflusssteuereinheit (9) ferner dafür ausgelegt
ist, um trotz der Druckveränderungen in der Hauptzufuhrleitung (1) eine konstante
Strömung aufrechtzuerhalten.
6. Verfahren nach einem der Ansprüche 4 oder 5, wobei ein externer Temperatursensor (8)
positioniert ist, um eine Temperatur außerhalb des Systems zu messen.
7. Verfahren nach Anspruch 6, wobei eine elektronische Steuereinheit (18) mit jeder Betätigungsvorrichtung
(10) verbunden ist und der Temperatursensor (11) mit der Rückführungsleitung (4) der
Wärmetauschervorrichtung (6) verbunden ist, in der er in der Wärmetauscherverbindung
positioniert ist.
8. Verfahren nach Anspruch 7, wobei die elektronische Steuereinheit mit einem Temperatursensor
(19), der mit der Hauptzufuhrleitung (1) verbunden ist, verbunden ist.
9. Verfahren nach einem der Ansprüche 7 oder 8, wobei jede Betätigungsvorrichtung mit
Impulsen betätigbar ist.
10. Verfahren nach Anspruch 9, wobei mindestens eine Betätigungsvorrichtung (10) ein elektromagnetischer,
pneumatischer, hydraulischer oder elektrostriktiver Antrieb ist.
11. Verfahren nach Anspruch 4 oder 5, wobei jede Betätigungsvorrichtung (10) direkt mit
einem Temperatursensor (11) verbunden ist und selbsttätig ist und Mittel enthält,
um den Sollwert der Rückführungstemperatur anzupassen, und wobei die Betätigungsvorrichtung
(10) ein Thermostat ist.
12. Verfahren nach einem vorhergehenden Anspruch, wobei die Zufuhrleitung und die Rückführungsleitung
(4) jeder Wärmetauschervorrichtung (6) zusätzlich durch eine Umgehungsleitung (5)
verbunden sind.
1. Procédé de régulation d'un système comprenant :
- un ensemble de dispositifs échangeurs de chaleur (6) reliés en série, de telle sorte
qu'une conduite de retour (4) d'un dispositif échangeur de chaleur (6) est une conduite
d'alimentation (3) d'un dispositif échangeur de chaleur suivant (6),
- une conduite d'alimentation principale (1) reliée à la conduite d'alimentation (3)
d'un premier des dispositifs échangeurs de chaleur (6), vu dans la direction d'écoulement,
- une conduite de retour principale (2) reliée à la conduite de retour (3) du dernier
des dispositifs échangeurs de chaleur (6), vu dans la direction d'écoulement,
où un milieu fluide d'échange de chaleur avec une température d'alimentation est introduit
depuis la conduite d'alimentation principale (1) dans l'ensemble de dispositifs échangeurs
de chaleur (6) à un débit, le débit étant régulé selon une température de consigne
de retour dépendant d'une température du milieu fluide d'échange de chaleur en aval
du premier dispositif échangeur de chaleur (6) dans l'ensemble,
caractérisé en ce que la température d'alimentation est régulée selon une température de consigne d'alimentation
dépendant de paramètres externes au système,
dans lequel la température de consigne de retour est régulée en réponse à une régulation
de la température de consigne d'alimentation.
2. Procédé selon la revendication 1, dans lequel le débit est régulé selon une température
de consigne de la température de retour du milieu fluide d'échange de chaleur après
le dernier des dispositifs échangeurs de chaleur (6), vu dans la direction d'écoulement.
3. Procédé selon la revendication 1 ou 2, dans lequel la température de consigne d'alimentation
est régulée en fonction d'une température externe au système.
4. Procédé selon l'une quelconque des revendications précédentes, dans lequel le système
comprend en outre
- un régulateur de débit (9) relié à une conduite de retour (4), le régulateur de
débit (9) étant adapté pour réguler le débit à travers la conduite de retour (4),
- un dispositif d'actionnement (10) faisant fonctionner le régulateur de débit (9),
et
- une sonde de température (11) positionnée en connexion d'échange de chaleur avec
le fluide d'échange de chaleur dans la conduite de retour (4).
5. Procédé selon la revendication 4, dans lequel chaque régulateur de débit (9) est en
outre adapté pour maintenir un débit constant malgré des changements de pression dans
la conduite d'alimentation principale (1).
6. Procédé selon une des revendications 4 ou 5, dans lequel une sonde de température
externe (8) est positionnée pour mesurer une température externe au système.
7. Procédé selon la revendication 6, dans lequel un contrôleur électronique (18) est
relié à chacun des dispositifs d'actionnement (10) et la sonde de température (11)
est reliée à la conduite de retour (4) du dispositif échangeur de chaleur (6) où elle
est positionnée en connexion d'échange de chaleur.
8. Procédé selon la revendication 7, dans lequel le contrôleur électronique est relié
à une sonde de température (19) reliée à la conduite d'alimentation principale (1).
9. Procédé selon une des revendications 7 ou 8, dans lequel chaque dispositif d'actionnement
est actionné par impulsions.
10. Procédé selon la revendication 9, dans lequel au moins un dispositif d'actionnement
(10) est un actionneur électromagnétique, pneumatique, hydraulique ou électrostrictif.
11. Procédé selon la revendication 4 ou 5, dans lequel chaque dispositif d'actionnement
(10) est directement relié à une sonde de température (11) et est automatique et comporte
des moyens pour ajuster la consigne de température de retour et dans lequel le dispositif
d'actionnement (10) est un thermostat.
12. Procédé selon une quelconque revendication précédente, dans lequel la conduite d'alimentation
et la conduite de retour (4) de chaque dispositif échangeur de chaleur (6) sont également
reliées par une conduite de dérivation (5).