Regulating method for a heating and/or cooling system with at least one load circuit
09851163 · 2017-12-26
Assignee
Inventors
Cpc classification
G05D23/1951
PHYSICS
Y02B30/00
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F28F27/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24D19/1009
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F24D3/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24F11/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F13/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24D3/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24D19/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F27/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A regulating method for a heating and/or cooling system uses at least one load circuit (6), through which a fluid as a heat transfer medium flows and switches the at least one load circuit (6) on and off in dependence on a room temperature in a room to be thermally regulated by the at least one load circuit (6). A feed temperature (T.sub.mix) of the fluid fed to the at least one load circuit (6) is set in dependence on the relative switch-on duration (D) of the at least one load circuit (6). A manifold device is also provided for a heating and/or cooling system with a control device for carrying out such a regulating method.
Claims
1. A regulating method for a heating and/or cooling system, the regulating method comprising the steps of: providing at least one load circuit, through which a fluid as a heat transfer medium flows; switching the at least one load circuit on and off in dependence on a room temperature in a room to be thermally regulated by the load circuit; and setting a feed temperature of the fluid fed to the at least one load circuit in dependence on the relative switch-on duration of the at least one load circuit, the relative switch-on duration corresponding to a ratio of the switch-on duration to a time interval between a switching-on of the at least one load circuit and a subsequent, renewed switching-on of the at least one load circuit.
2. A regulating method according to claim 1, wherein the load circuit is used for heating the room and at least one of: the feed temperature is increased if the relative switch-on duration exceeds a predefined limit value; and the feed temperature is lowered if the switch-on duration falls short of a predefined limit value.
3. A regulating method according to claim 2, wherein the feed temperature is changed by a proportional amount on falling short of or exceeding the predefined limit value.
4. A regulating method according to claim 1, wherein the load circuit is used for cooling the room and at least one of: the feed temperature is lowered if the relative switch-on duration exceeds a predefined limit value; and the feed temperature is increased if the relative switch-on duration falls short of a predefined limit value.
5. A regulating method according to claim 4, wherein the feed temperature is changed by a proportional amount on falling short of or exceeding the predefined limit value.
6. A regulating method according to claim 1, further comprising the steps of: providing a mixing device; using the mixing device for setting the feed temperature such that fluid fed to the at least one load circuit is mixed with fluid from the return of the at least one load circuit.
7. A regulating method according to claim 1, wherein several load circuits are provided and the relative switch-on duration of that load circuit having the longest relative switch-on durations forms the basis for setting the feed temperature of a fluid fed to all load circuits.
8. A regulating method according to claim 1, wherein the room temperature is detected in the room to be thermally regulated by the load circuit, and the load circuit is switched off by way of interrupting the volume flow if the room temperature reaches a temperature setpoint.
9. A regulating method according to claim 1, wherein an entry temperature of the fluid at an entry of the load circuit and an exit temperature of the fluid at an exit of the load circuit are detected, a temperature difference between the entry temperature and the exit temperature is determined, and a volume flow of the fluid through this load circuit is set in dependence on the temperature difference.
10. A regulating method according to claim 1, further comprising the steps of: providing a circulation pump, wherein several load circuits are provided and the circulation pump is provided for the several load circuits; delivering fluid with the circulation pump; regulating a speed of the circulation pump in a manner such that a differential pressure across the circulation pump corresponds to a predefined pressure difference setpoint.
11. A regulating method according to claim 10, wherein the pressure difference setpoint for the differential pressure across the circulation pump is set in dependence on the opening degree of at least one of the regulating valves for setting the volume flow in the load circuits.
12. A regulating method according to claim 11, wherein for setting the pressure difference setpoint for the differential pressure across the circulation pump, a regulating valve which is open the furthest is considered, wherein an opening degree of said regulating valve which is open the furthest is compared to a desired opening degree, and the pressure difference setpoint is increased on exceeding the desired opening degree, and the pressure difference setpoint is reduced on falling short of the desired opening degree.
13. A manifold device for a heating and/or cooling system, the manifold device comprising: at least one load circuit through which a fluid as a heat transfer medium flows; a control device configured for carrying out a regulating method, the regulating method comprising the steps of: switching the at least one load circuit on and off in dependence on a room temperature in a room to be thermally regulated by the load circuit; and setting a feed temperature of the fluid fed to the at least one load circuit in dependence on the relative switch-on duration of the at least one load circuit, the relative switch-on duration corresponding to a ratio of the switch-on duration to a time interval between a switching-on of the at least one load circuit and a subsequent, renewed switching-on of the at least one load circuit.
14. A manifold device according to claim 13, further comprising a feed temperature setting device comprising a mixing device in which fluid fed to the at least one load circuit is mixed with fluid from a return of the at least one load circuit.
15. A manifold device according to claim 13, wherein the mixing device comprises a fluid feed or a mixing conduit connecting the return of the load circuit to the entry of the at least one load circuit and a valve regulating the flow, wherein a valve opening degree is settable by the control device.
16. A manifold device according to claim 13, further comprising another load circuit such that several load circuits are provided, wherein the feed temperature setting device sets the feed temperature of a fluid fed to all load circuits.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(6) Referring to the drawings,
(7) The heating system shown in
(8) Moreover, a mixing device is arranged upstream of the circulation pump assembly 8. The mixing device comprises a mixing conduit 12 which connects a return 14 from the load circuits 6 to a mixing point 16 in the flow path from the inlet 2 to the circulation pump 8. I.e. fluid from the inlet 2 is mixed with fluid from the return 14, at the mixing point 16, in order to be able to set the feed temperature. A regulating valve which forms a mixing valve 18 is arranged in the return 14, downstream of the branching 17 of the mixing conduit 12 in the return 14, for the regulation of the mixing ratio. This is likewise signal-connected to the control device 10 for its activation. Moreover, a check valve 20 is arranged in the mixing conduit 12 and prevents the backflow of fluid from the mixing point 16 into the return 14. The volume flow which flows out of the return 14 to the outlet 4 changes in a manner depending on the opening degree of the mixing valve 18. If the volume flow is reduced by way of a reduction of the opening degree of the mixing valve 18, a greater share of the fluid flows through the mixing conduit 12 to the mixing point 16. If the opening degree of the mixing valve 18 increases, the volume flow through the outlet 4 increases and accordingly a smaller share of the fluid flow flows from the return 14 through the mixing conduit 12 to the mixing point 16. Thus, the share of fluid from the return 14 and which is admixed at the mixing point 16 to the fluid out of the inlet 2 changes. The feed temperature of the fluid from the inlet 2 can be lowered by way of the mixing of the fluid from the return 14 and which is colder in the case of a heating system, with the warmer fluid from the inlet 2. In the case of a cooling system, vice versa warmer fluid from the return 14 is admixed to the colder fluid from the inlet 2, in order to increase the feed temperature. The circulation pump 8 delivers the fluid from the mixing point 16 to the load circuits 6 arranged in parallel.
(9) In each case, a regulating valve 24 is arranged at the exits 22 of the load circuits, i.e. in their returns, and this valve is designed as an electromotorically driven regulating valve 24 and is activated by the control device 10. The regulating valves 24 can be varied in their opening degree and also be completely closed, in order to set the flow or volume flow through each individual load circuit 6. Thereby, the regulating valves 24 can be individually activated by the control device 10, so that an adaptation of the flow through each individual load circuit 6 is possible independently of the remaining load circuits.
(10) Moreover, temperature sensors are provided in the shown system. A first temperature sensor is a feed temperature sensor 26 and detects the feed temperature of the fluid which is fed to the load circuits 6. Moreover, temperature sensors 28 are arranged at the exits 22 of the load circuits 6 and detect the exit temperatures of the fluid from the individual load circuits 6. The temperature values which are detected by the feed temperature sensor 26 and the temperature sensors 28 are led via suitable communication connections likewise to the control device 10.
(11) The circulation pump assembly 8 is moreover designed to determine a differential pressure H.sub.pu between the entry side and the exit side of the circulation pump assembly 8 and which simultaneously corresponds to the differential pressure between the entries 30 and the mixing point 16, i.e. which corresponds to the pressure drop via each branches between these points which are defined by the load circuit 6. Moreover, the circulation pump assembly 8 is designed to determine the flow through the circulation pump assembly 8. These values detected by the circulation pump assembly 8 are likewise led via a signal connection to the central control device 10. Alternatively, suitable pressure sensors and flow sensors could be arranged additionally to the circulation pump assembly 8, in order to determine the pressure difference between the entry and exit of the load circuits 6 as well as the flow through all load circuits 6.
(12) On basis of the differential pressure H.sub.pu, i.e. the pressure drop via the load circuit can be used in regard to the characteristic of the valves lying in the flow path, particularly of the check valve 20 and the regulating valve 24, moreover, the volume flow through each load circuit 6 depending on the opening degree of the per-respective valve 24 can be determined. Since the controller 10 controls the opening degree of the regulating valves 24, the control device 10 can determine the flow rate or volume flow rate through the associated load circuit 6 from the said values.
(13) Thus, as described below, a desired flow rate can be adjusted by the load circuit 6.
(14) The control device 10 is moreover provided with a communication interface 32 which is designed to communicate with one or more room thermostats 34 or room temperature probes 34. Such a room thermostat 34 is preferably provided in each room which is to be thermally regulated by a load circuit 6. In the shown example, the communication interface 32 is designed as a radio interface which communicates with corresponding radio interface 36 of the room thermostat 34. Alternatively, a lead connection via a separate signal lead, a bus system or a powerline communication could be provided. The room thermostats 34 detect the room temperatures in the rooms to be thermally regulated. Moreover, a desired temperature for the room to be thermally regulated can be set by the user in each case in the known manner via the room thermostats 24.
(15) The control device 10 is designed for the use of different regulating methods. Thus, according to a first regulating method, the control device 10 effects a volume flow regulation for the individual load circuits 6. For this, the temperature difference ΔT between the entry 30 and the exit 22 of each load circuit 6 is detected. This is effected via the feed temperature sensor 26 as well as the temperature sensor 28 belonging to the respective load circuit 6. The volume flow is regulated or set by the control device 10 by changing the opening degree V.sub.pos,n of the regulating valve 24 in dependence on this temperature difference ΔT, via the regulating valve 24 of this load circuit 6, so that the temperature difference ΔT corresponds to a predefined setpoint which is stored in the control device 10, i.e. that ΔT is kept constant. This is effected independently for each load circuit 6, so that all load circuits can be adapted by the volume flow regulation to the actual energy requirement. The setpoint can be the same for all load circuits 6 or different setpoints can be defined for individual load circuits. The setpoints are stored in the control device 10.
(16) Thereby, the circulation pump assembly 8 is regulated by the control device 10 such that it maintains a predefined pressure difference setpoint between the entry and exit of the circulation pump assembly. This differential pressure is thus regulated to a pressure difference setpoint which is likewise set or defined by the control device 10. The pressure difference setpoint H.sub.ref is set by the control device 10 in dependence on the opening degree of the regulating valves 24. For this, all opening degrees of all regulating valves 24 are considered by the control device 10. That regulating valve which is presently open the furthest, i.e. has the greatest opening degree, then forms the basis of the setting of the pressure difference setpoint by the control device 10. Thus, the opening degree of the regulating valve which is open the furthest, is compared to a desired opening degree V.sub.pos,ref. If the present or current opening degree V.sub.pos,n of the regulating valve 24 with the greatest opening degree exceeds the desired opening degree V.sub.pos,ref, then the pressure difference setpoint H.sub.ref is increased. If the desired opening degree V.sub.pos,ref is fallen short of by the actual opening degree V.sub.pos,n, then the pressure difference setpoint H.sub.ref is accordingly lowered. The increase or lowering is preferably effected proportionally to the deviation from the desired opening degree V.sub.pos,ref.
(17) A further control loop or a further regulating method which is carried out by the control device 10 relates to the regulation of the feed temperature T.sub.mix at the entry 30 of the load circuits 6 and which is detected by the feed temperature sensor 26. The feed temperature T.sub.mix can be changed or set by the control device 10 by way of activation of the mixing valve 18. For this, the control device 10 forms a feed temperature setting device which sets the feed temperature T.sub.mix, i.e. its setpoint in dependence on the switch-on duration, i.e. the relative switch-on duration D of the load circuits 6. The significance of the relative switch-on duration D is described in more detail by way of
(18) The feed temperature T.sub.mix and its setpoint is the same for all load circuits 6 and is set by the control device 10 in dependence on that load circuit 6 which has the longest relative switch-on duration D, i.e. the relatively largest load cycle. This is the load circuit 6 with the greatest thermal or cooling requirement, so that it is useful to adequately set the feed temperature T.sub.mix for this load circuit 6. The remaining load circuits 6 which have lower relative switch-on durations D accordingly have a lower energy requirement, so that the set feed temperature T.sub.mix for these load circuits is likewise sufficient. The setting of the feed temperature T.sub.mix is effected in a manner such that the relative switch-on duration D is compared to a limit value or a desired switch-on duration D.sub.ref. If the relative switch-on duration D exceeds the desired switch-on duration D.sub.ref, the feed temperature T.sub.mix respectively at first its setpoint is increased in the case of a heating, and the feed temperature T.sub.mix respectively its setpoint is reduced in the case of a cooling system. Vice versa, for the case that the relative switch-on duration D falls short of the desired switch-on duration D.sub.ref, the feed temperature T.sub.mix respectively its setpoint is reduced in the case of a heating, and increased in the case of a cooling system. This is preferably effected proportionally to the deviation of the switch-on duration D from the desired switch-on duration D.sub.ref. Alternatively, a change can also be effected in fixed steps. The desired switch-on duration D.sub.ref is stored as a preset value in the control device 10.
(19) It is shown in
(20) A second control loop R.sub.2 which is represented in
(21) A third control loop R.sub.3 and a fourth control loop R.sub.4 which are shown in
(22) The four shown control lops R.sub.1, R.sub.2, R.sub.3, R.sub.4 are differently quick and differently sluggish, so that they preferably do not interact with one another, i.e. they do not mutually influence one another. The quickest control loop is the control loop R.sub.4 which regulates the pressure difference H.sub.pu across the circulation pump assembly 8 to the pressure difference setpoint H.sub.ref. The next slower control loop is the control loop R.sub.1 which regulates the volume flow through the individual load circuits 6. Even slower is the control loop R.sub.3 which regulates the pressure difference setpoint H.sub.ref. This control loop is so slow that this regulation preferably does not influence the control loop R.sub.1. In
(23) Apart from the regulation method described above, the control device 10 can also assume further functions. It is possible to store certain priorities for the individual load circuits 6 in the control device 10, since this control device communicates with room thermostats 34 and switches on the load circuits 6 by way of opening the regulating valves 24, in dependence on the signals from the room thermostats 34. Thus, with a heating system and when very cold, it is possible for example to not simultaneously activate all load circuits 6 in the case that the heat quantity made available by the boiler would not be sufficient. For heating, firstly prioritised heating circuits such as for example living rooms or bath can be switched on, and less important load circuits 6, for example for heating bedrooms can firstly remain switched off. Thereby, the control device 10 can automatically detect that the heating power available is not sufficient, specifically when all regulating valves 34 are opened, i.e. have the maximal opening degree and despite this the temperature difference ΔT between the entry 30 and the exit 22 becomes too large. This functions in a corresponding manner also with a cooling system, but in reverse. The priority of the load circuits 6 can be preset and be stored in the control device 10. Moreover, the control device 10 can also be designed such that for heating rooms, it increases the feed temperature T.sub.mix for a certain time above the usually sought setpoint resulting from the previously described regulation, in order to permit a rapid heating of the rooms.
(24) Finally, the control device 10 can also have a diagnosis function or diagnosis module which diagnoses the correct function of the regulating valves 24 as well as of the load circuits 6. Thus, the control device 10 in a diagnosis mode can individually open the regulating valves 24 of the load circuits 6 or increase or reduce the opening degree of the regulating valves 24, ideally to the maximum. Thereby, in each case only one regulating valve 24 is opened and closed further departing from an initial opening degree, whilst the other regulating valves 24 remain unchanged or closed. Preferably the regulating valve 24 of the load circuit 6 which has to be rechecked is further opened. Subsequently, the flow through the circulation pump assembly 8 as well as the differential pressure across the circulation pump assembly 8 is detected and the hydraulic resistance of the system respectively a change of the hydraulic resistance is determined from this. The control device 10 also receives information or signals from the circulation pump assembly 8 which specifies the flow and the differential pressure. The control device 10 compares the determined hydraulic resistance with a maximum hydraulic resistance with is predefined for the system and which is stored in the control device 10. If the detected hydraulic resistance exceeds the predefined maximum hydraulic resistance, this indicates an error and the control device 10 signalises this error, so that the system can be subsequently examined. If the hydraulic resistance before and after the opening of the regulating valve 24 are compared to one another, then the correction function of the regulating valve 24 can be determined from this. Moreover, the hydraulic resistance can also be compared to a minimal value in the control device 10. If a stored minimal value is fallen short of, then likewise a malfunction can be deduced from this.
(25) The diagnostic function described above can be also realized so that the pressure loss and hence, the hydraulic resistance is taken into account only the individual load circuits 6 or determined by the control device 10. This can also be done by knowing the characteristics of the valves lying in the flow path, especially the check valve 20 and the regulating valve 24 taking into account the known opening degree of the valves 24. If the pressure losses of the valves are known in the given operating state, then the proportion of the total pressure loss of the circulation pump 8 which is provided between input and output can be determined, which is caused by the respective load circuit 6 itself. Accordingly, the permissible limits for the pressure loss and the hydraulic resistance of the load circuit 6 itself can be parked. I.e., it will only take into account the hydraulic resistance of the load circuit in the comparison with the permissible limits, the limits are limits for the hydraulic resistance of the load circuit.
(26) The essential components of the heating system shown in
(27) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
APPENDIX
List of Reference Numerals
(28) 2—inlet 4—outlet 6—load circuits 8—circulation pump assembly 10—control device 12—mixing conduit 14—return 16—mixing point 17—branching 18—mixing valve 20—check valve 22—exits 24—regulating valve 26—feed temperature sensor 28—temperature sensors 30—inputs 32—communication interface 34—room thermostat 36—radio interface 38—detection device 40—heating manifold 42—pump housing 44—stator housing 46—electronics housing 48—manifold R.sub.1, R.sub.2, R.sub.3, R.sub.4—control loops T.sub.mix—feed temperature T.sub.ret,n—exit temperature ΔT—temperature difference ΔT.sub.ref—temperature difference setpoint H.sub.pu—differential pressure H.sub.ref—pressure difference setpoint V.sub.pos,ref—desired opening degree V.sub.pos,mix—opening degree of mixing valve 18 V.sub.pos,n—opening degree of regulating valve 24 D—relative switch-on duration D.sub.ref—desired switch-on duration t.sub.z—cycle time t.sub.on—switch-on time t.sub.off—switch-off time S.sub.pu—speed P.sub.pu—power