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US3608818A - Heating system control - Google Patents

Heating system control Download PDF

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Publication number
US3608818A
US3608818A US830993A US3608818DA US3608818A US 3608818 A US3608818 A US 3608818A US 830993 A US830993 A US 830993A US 3608818D A US3608818D A US 3608818DA US 3608818 A US3608818 A US 3608818A
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Prior art keywords
pump
feed line
line
way valve
valve
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Expired - Lifetime
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US830993A
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English (en)
Inventor
Jost Eduard Von Fellenberg
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Priority claimed from CH890668A external-priority patent/CH501192A/de
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00—Details
    • F24D19/10—Arrangement or mounting of control or safety devices
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1009—Arrangement or mounting of control or safety devices for water heating systems for central heating
    • F24D19/1012—Arrangement or mounting of control or safety devices for water heating systems for central heating by regulating the speed of a pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D3/00—Hot-water central heating systems
    • F24D3/02—Hot-water central heating systems with forced circulation, e.g. by pumps

Definitions

  • a variable-speed pump is provided in a liquid feed line between a boiler and a heat exchanger, while a bypass line extends from a return line between the heat exchanger and boiler to a three-way valve in the feed line upstream from the pump.
  • the pump speed is varied as a function of temperature changes and liquid pressure variations in the feed line under varying pump speeds actuate a control for the three-way valve.
  • the pump speed is constant and liquid pressure variations in the feed line are produced by a temperature-responsive: throttle valve.
  • This invention relates to a control of heating systems working with liquid heat medium and having at least one circulating pump in the heat medium circulation system and further having a device for the admixture of returning cooled liquid to the forward flow, with the object of attaining and maintaining a control quantity, in particular the forward-line or room temperature, wherein the adjustment of the return admixture device is effected with the aid of a pressure difference developed by the circulating pump.
  • Central heating systems with liquid heat media and constant temperature in the heat reservoir are normally provided with a bypass line which bypasses the heat reservoir or heat source and which passes into the forward line through a three-way mixing element.
  • This three-way mixing element may be operated by a setting motor, for instance, controlled by a controller.
  • the controller in its turn receives its signals from temperature probes arranged in the heat medium forward line and in a room, for instance.
  • the controller ensures that by suitable setting of the mixing element the heat medium flows from the forward-line to the radiators with the appropriate mixing temperature, so that the heat emission of the radiators has a stationary pattern at the planned or preset temperature or the target temperatures.
  • the forward line temperature is regulated by means of the controller.
  • This con trol is termed atmospheric control, wherein the outside temperature constitutes the reference quantity, and the forwardline temperature the control quantity.
  • Temperature control systems could be based on room temperature or constant forward-line temperature alone.
  • a thermal drive such as one operated by a bimetallic element, bringing the mixing element into the position required by the controller.
  • the object of the present invention is to provide a system which avoids the aforesaid drawbacks and permits the construction of a heating system which keeps the rooms to be heated at practically constant temperatures.
  • the said system is characterized in that at least part of the pressure difference is varied by way of control action
  • the heating system in which a pressure-differential-controlled flow control element each is arranged between the heat source and the junction of the bypass line with the forward line and also in the bypass line itself for the purpose of developing a preset forward-line mixing temperature, is characterized in that it has a controller controlling the means for varying the pressure difference.
  • FIG. 1 shows a diagram of a central heating system according to the invention
  • FIGS. 2 and 3 show diagrams of control elements in the forward-line and in the bypass line of the heating system, with a circulating pump diagrammatically indicated
  • FIG. 4 shows a circuit diagram of an automatic control device for a mixed water pump heating system
  • FIG. 5 shows a circuit diagram of a heating system representing one embodiment of the invention
  • FIG. 6 shows a variant circuit of a heating system analogous to that in FIG. 5;
  • FIG. 7 shows a set of characteristics with operating point of the circulating pump according to FIG. 41;
  • FIG. g shows a set of pump characteristics for fixed total resistance of the system and variable speed of the circulating pump
  • FIG. 9 shows a set of pump characteristics for variable pump speed and variable system resistance.
  • a boiler forward-line 3 leads through a pump forward-line 5 to a circulating pump 7. From this, a supply line 9 conducts the heat medium to a radiator ill. After dissipating part of its heat, the heat medium returns through a return line 13 to boiler ll.
  • a bypass line 15 permits the boiler 1 to be bypassed and cooler return water to be admixed to the hot heat medium in the boiler forward-line 3.
  • a pressure-differential control 116 of known type with a setting motor 17 and a valve 119, whose construction is described more closely below.
  • the valve 19 is provided on its stem 22 with a valve disk 20 which, when closed, rests either on the seat of a valve seat plate 1% or on the end of the bypass pipe 15 designed as a valve seat.
  • the connection of the pump intake line 5 with one side of the diaphragm 27 is by a line 24, while that of the pump delivery line or supply line 9, with the other side of the diaphragm 27 is by a line 26.
  • An outside temperature probe 21 and a forward water temperature probe 23 act on a controller 25, which in its turn influences the speed of the circulating pump 7, so that the flow of heat medium circulating in the heating system can be increased and the delivery rate of the circulating pump also rises according to the pump characteristics as a result of the rising resistances in the system.
  • the diaphragm 27 is fixed around its periphery, and its resetting power is based on its elasticity and can, if necessary, be assisted by an adjustable recovery spring (not shown).
  • the system is so designed that when the outside temperature falls and, accordingly, the temperature near the radiator ill falls, the target value of the temperature of the forward water rises and the required forward water temperature is reached by variation of the pump speed.
  • the controller 25 increases the speed of the circulating pump 7, thus increasing the pressure difference developed by the pump, the delivery rate, between intake and delivery sides and also increasing the throughput.
  • This in crease in the differential pressure affects the control 16 in such a way that the forward line 3 opens to a corresponding degree and the bypass line 15 closes to a corresponding degree, in other words, is adjusted towards the closing position.
  • the valve disk 20 moves towards the junction of the bypass line 115.
  • the outside thermometer it is of course also possible to install a room thermometer, which acts on the controller 25 accordingly.
  • the controller 25 is adapted to the requirements of the circulating pump 7 and the drive motor of the pump 7.
  • the control 16 is so arranged that in extreme operating conditions it fully opens the forward-line 3 and fully closes the bypass line 15, or vice versa.
  • FlG. 2 shows a diagram of a section of the heating system in the range of the circulating pump 7 and the forward-line 3 as well as the bypass line 15.
  • the forward-line 3 and the bypass line 15 are connected to the side of the valve housing 50.
  • the outflow is through the circulating pump intake line 5 which is followed by the circulating pump 7.
  • Arranged in the valve housing 56) are two cages 52 and 54k
  • a valve stem 56 is provided with valve disks 59 and 60 for the forward-line 3 and for the bypass line 15, respectively.
  • a spring 63 supported on the cage 54 develops the particular resetting power for the valve stem 56.
  • a floating plunger 65 Arranged at one end of the valve stem 56 and facing the pump 7 is a floating plunger 65.
  • the setting force is varied in correlation with the pump speed and the pump delivery rate and the delivery pressure by means of the floating plunger 65.
  • the floating plunger 65 moves towards the pump 7 and thus opens the valve disk 59 for the boiler forward-line 3 and moves the valve disk 60 towards the seat of the cage 54, i.e. with closing effect.
  • the forward-line mixing temperature increases, as was intended by the increase of the speed of the circulating pump 7.
  • the spring 63 provides the counterforce to the drag on the floating plunger 65. This spring 63 acts as a recovery spring.
  • the embodiment shown in FIG. 3 again comprises two cages 71 and 72 in a valve housing 70, and also a valve stem 74 with the valve disks 77 and 78.
  • the free end of the valve stem 74 is attached to a diaphragm 81, representing the setting motor.
  • it divides the valve housing 70 into an intake chamber and a delivery chamber.
  • the valve stem 74 and the disks 77 and 78 are moved by the difference, acting on the diaphragm 81, of the pressure-produced forces. This movement also produces the necessary resetting power.
  • the diaphragm is pushed to the left when the pressure differential rises.
  • the orifice of the mixing valve for the boiler forward-line is opened by the valve disk 77 moving away from its seat in the cage 71.
  • the orifice of the mixing valve for the bypass line is closed by the valve disk 78 moving towards the seat of its cage 72.
  • the circulating pump may be a displacement pump, an impeller pump or a centrifugal pump. It is preferably driven by a speed-controllable electric motor, possibly fed by the controller as a power source.
  • valves For the resetting of the valves, it is also possible to use means other than springs, such as pneumatic elements, which can be set by suitable means, such as vanes, etc. If necessary, central operation may be provided for the resetting elements. It is also possible to interconnect several quantity control elements rigidly, as described, or elastically, as by a spring.
  • the spring forces and their interrelation it is possible to set the heating characteristics of the heating system in relation to the object to be heated (building, building section, room, etc.). Likewise, it is possible by the choice of the spring forces to determine the capacity range, in other words, the working range, within which the circulating pump is controlled.
  • outside temperature and forward-line temperature i.e. the quotient thereof
  • gradient The correlation of outside temperature and forward-line temperature, i.e. the quotient thereof, is termed gradient.
  • the controller together with all its setting and operating means and, where required, with a clock for the time program, can be designed to form a unit with circulating pump and control elements.
  • the simplest practice is to provide the pump with an adjustable throttle-valve which can be fixed and set when the system is installed and which can be used to adjust the resistance parabola of the whole system for a particular pump type to the target parabola.
  • an adjustable throttle-valve which can be fixed and set when the system is installed and which can be used to adjust the resistance parabola of the whole system for a particular pump type to the target parabola.
  • throttle-valve is closed to a greater or lesser degree. This permits the pump with its predetermined variable speed range to be supplied irrespective of the particular system, as it always runs on the same curve section of the resistance parabola.
  • Another solution which, while more complicated, is possible cheaper in operation, consists in tuning the variable speed range by setting the corresponding pump speed for the purpose of obtaining a preset normal throughput per radiator. This speed-setting can be achieved by the connecting of electric resistances. However, owing to the changed target value of the control pressure difference for the mixing element, this solution also requires tuning of this mixing element.
  • a basic idea as was described with reference to the embodiments, consists in having an arrangement wherein a primary control function mainly influences the admixing ratio, while a secondary control function, derived therefrom, mainly influences the circulating quantity. This thus involves two mutually sup:
  • FIG. 4 shows the diagram of a known system, comprising a boiler 85, one or several radiators 87, an admixing valve 89 and a circulating pump 90 with a pump motor 91.
  • a boiler forward-line 93 leads from the boiler to the admixing valve 89, while a supply line 95 from the circulating pump supplies the radiator or radiators 87 with forward-line hot water.
  • a return line 97 passes the cooled water from the radiator 87 either to the boiler 85 or through a bypass line 98 to the admixing valve 89.
  • the admixing valve 89 is controlled by a room thermostat 103, which controls a solenoid valve 101 in a pressure line 100 in such a way that the solenoid valve, when open, permits the full pressure from the delivery side of the pump 90 to act on the admixing valve 89 or, when closed, keeps the admixing valve 89 pressureless.
  • the radiators 87 are supplied either with water circulating through the boiler 85 or with the water through the bypass line 98, in which case the boiler 85 is completely bypassed.
  • This arrangement basically keeps the temperature and the throughput of the heat medium in the system constant, as the resistance relations in the system in bypassing as well as in passing through the boiler are approximatelyequal, i.e. equalized.
  • FIG. 5 shows part of the circuit of the system according to FIG. 1.
  • the forward water temperature probe 23 acts on the controller 25, which in its turn controls the drive motor SM of the circulating pump 7 in this variant and varies its speed.
  • This varies, according to the pump characteristics (FIG. 8), 82 the pressure difference delta p which exists in the lines 24 and 26 and which adjusts the control 16 accordingly.
  • the latter controls the quotas of the hot water coming from the boiler forward-line 3 and the quotas of the colder return water coming from the return line 13 through the bypass line 15.
  • the control process can be easily seen from the pump characteristics in FIG. 8.
  • the system resistance W is constant.
  • Varying the normal speed n to n or n 2 varies the working point 6 to 6, or 6 as according to the resistance parabola W of the whole heating system a greater throughput Q implies a correspondingly greater pressure drop delta p
  • Analogous considerations apply to the operating point (1
  • the object of this control is to vary the control quantity of the mixing valve 16, and with it, the ratio between the quantity of hot water and that of returned water by varying the value of delta p. This results in a variation of the total throughput Q according to the pump characteristics, as may be seen from FIG. 8. This throughput variation has the positive effect of assisting the control process started.
  • the quantity of water flowing through the heating system is smaller, as part of it is continually extracted after the pump and returned through the bypass line 110 to the pump intake side, so that this control can achieve the same effect as regards the heating aspect as can the speed control towards lower speeds n
  • the bypass control is achieved at the price of lower efficiency, as the total circulation quantity is increased and the power input of the pump rises accordingly, despite the smaller water quantity put through the heating system.
  • FIG. 6 shows a circuit according to the invention in which the speed of the circulating pump 7 is constant.
  • a throttle-valve 114 in the form of a flap or a control valve, whose position is influenced by the forward water temperature probe 23 through the controller 25.
  • Such a throttle-valve 114 permits the total resistance W of the heating system to be varied, which shows in the position of the resistance parabolas given in Fig. 9 for instance, where the parabola W represents a mean value, W, the total resistance with throttle-valve 114 open, and W the total resistance of the system under heavy throttling.
  • the differential pressure delta p developed by the pump 7 and used to control the mixing valve 16 is varied.
  • the whole circuit can be so arranged that the varying total throughput varies in accordance with the intended variation, i.e. so that with increasing heat supply to the consumer the total throughput rises by the throttle-valve 1141 opening, in which process the mixing valve 16 influences the boiler forward-line 3 with opening effect and the return water line with closing effect.
  • a heating system to the total through-flow system is preferably achieved by speed control of the pump or then with the aid of a throttle device as shown in Figs. 5 and 6.
  • the idea of the invention can also be implemented by an arrangement in which the pressure difference developed by the circulating pump and acting on the return admixture device is controlled by a throttle-valve 118 in a connecting line 119 between the pressure extraction lines 24 and 26, in a continuously controllable manner, for instance.
  • a throttle-valve 118 in a connecting line 119 between the pressure extraction lines 24 and 26, in a continuously controllable manner, for instance.
  • the subject matter of the invention involves a further sim plification of the electric installation:
  • the usual practice of also switching off the circulating pump when the heating is turned off necessitates, in an automatic system, an additional switch or a contact in the program selection device and its electric connecting line to the circulating pump.
  • the circulating pump is turned off in order to turn off the heating.
  • the pump pressure becomes zero, the valve in the boiler forward-line closes, and that in the bypass line opens.
  • a heating system the combination of a liquid boiler, a heat exchanger, a closed liquid circuit including a feed line and a return line between said boiler and said heat exchanger, a three-way valve in said feed line, a bypass line from said return line to said three-way valve, a variable-speed circulating pump in said feed line between said three-way valve and said heat exchanger, and control apparatus comprising a temperature-sensing device, a speed control responsive to said temperature-sensing device for varying the speed of said pump so that the pump speed is increased when the temperature sensed by said device decreases and vice versa, and means responsive to liquid pressure variations in said feed line under the varying speed of said pump for actuating said threeway valve, so that less liquid is circulated through said bypass line when the feed line pressure increases and vice versa.
  • said means responsive to liquid pressure variations in said feed line comprise a pressure-differential controller including a diaphragm and a pair of chambers at opposite sides of said diaphragm connected to said feed line at points respectively upstream and downstream from said pump, and means operatively connecting said diaphragm to said three-way valve.
  • said means responsive to liquid pressure variations in said feed line comprise a drag-actuated control member movable in upstream and downstream directions in the feed line and operatively connected to said three-way valve, and means biasing said control member in the upstream direction, increasing speed of said pump and resultant increasing pressure of the pumped liquid producing increasing drag to move said control member downstream against the upstream biasing means.
  • control system as defined in claim 1 together with a pump bypass connected to said feed line at points upstream and downstream from said pump and downstream from said three-way valve, and a throttle valve in said pump bypass, said throttle valve being actuated by said temperature-sensing device.
  • a heating system the combination of a liquid boiler, a heat exchanger, a closed liquid circuit including a feed line and a return line between said boiler and said heat exchanger, a three-way valve in said feed line, a bypass line from said return line to said three-way valve, a circulating pump in said feed line between said three-way valve and said heat exchanger, and control apparatus comprising a temperaturesensing device, a throttle valve in said feed line between said pump and said heat exchanger, said throttle valve being responsive to said temperature-sensing device for varying the back pressure against said pump, and means responsive to pump back pressure variations in the feed line for actuating said three-way valve.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Steam Or Hot-Water Central Heating Systems (AREA)
  • Multiple-Way Valves (AREA)
  • Reciprocating Pumps (AREA)
US830993A 1968-06-15 1969-06-06 Heating system control Expired - Lifetime US3608818A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH890668A CH501192A (de) 1968-06-15 1968-06-15 Verfahren zum Regeln von Heizungsanlagen und Heizungsanlage zur Ausführung des Verfahrens
CH778569A CH510237A (de) 1968-06-15 1969-05-22 Verfahren zum Regeln von Heizungsanlagen und Heizungsanlage zur Ausführung des Verfahrens

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US3608818A true US3608818A (en) 1971-09-28

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US830993A Expired - Lifetime US3608818A (en) 1968-06-15 1969-06-06 Heating system control

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US (1) US3608818A (xx)
BE (1) BE734567A (xx)
CH (1) CH510237A (xx)
DE (2) DE1928575B2 (xx)
FR (1) FR2010967A1 (xx)
GB (1) GB1233647A (xx)
NL (1) NL6909026A (xx)
SE (1) SE351482B (xx)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873022A (en) * 1972-06-14 1975-03-25 Tour Agenturer Ab Regulating station
US3999598A (en) * 1974-02-22 1976-12-28 Suddeutsche Kuhlerfabrik, Julius Fr. Behr Water temperature regulator
US4050626A (en) * 1975-04-18 1977-09-27 Awalt Jr Thomas Y Supplemental heat and heat transfer subsystems for solar air conditioning systems
US4207866A (en) * 1977-09-15 1980-06-17 Boyd Rodney E Solar heating system including freeze protection
US4388964A (en) * 1979-10-11 1983-06-21 Arthur D. Little, Inc. Thermal control system
US4700548A (en) * 1986-03-05 1987-10-20 Ontario, Inc. Control apparatus for ice rink refrigeration equipment
EP0374424A1 (en) 1988-11-30 1990-06-27 General Electric Company Silicon infiltrated porous polycrystalline diamond compacts and their fabrications
DE4002502A1 (de) * 1989-02-02 1990-08-09 Vaillant Joh Gmbh & Co Wasserheizungsanlage
US6732791B2 (en) * 1999-12-31 2004-05-11 Stac, Inc. Hydraulic oil cooler and supplying vessel pressure stabilizer
US20100212604A1 (en) * 2007-05-10 2010-08-26 Kyungdong Navien Co., Ltd. Hot water supplying system
CN101922760A (zh) * 2010-09-01 2010-12-22 余志锋 热水器出水管路冷水回用装置
US20100329650A1 (en) * 2008-06-24 2010-12-30 Yong-Bum Kim Hot water supply system for constantly maintaining temperature of hot water
US20100326646A1 (en) * 2008-06-27 2010-12-30 Yong-Bum Kim Method for controlling a hot water temperature using low flux in hot water supply system
US20150136377A1 (en) * 2013-11-19 2015-05-21 Grundfos Holding A/S Method for a heat transfer system and heat transfer system
US20160305671A1 (en) * 2013-12-05 2016-10-20 Zonealone Limited A domestic hot water installation
CN108139084A (zh) * 2015-10-02 2018-06-08 格兰富控股联合股份公司 液压系统
US10830458B2 (en) 2015-10-02 2020-11-10 Grundfos Holding A/S Hydraulic system
US20230109989A1 (en) * 2021-10-07 2023-04-13 Accademia Europea Bolzano - Eurac Research Regulation system for a thermo-hydraulic circuit and control method

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FR2211108A5 (xx) * 1972-12-20 1974-07-12 Pont A Mousson
IT1036636B (it) * 1975-07-25 1979-10-30 Ve Ma Elettropompe Spa Perfezionamento nei mezzi per la regolazione della temperatura di ambienti particolarmente per impianti di riscaldamento a circo lazione forzata di fluido
DE2940790C1 (de) * 1979-10-09 1982-03-18 Fa. Rud. Otto Meyer, 2000 Hamburg Verfahren zur energiesparenden Temperaturregelung von Waermeversorgungsanlagen
CH641889A5 (de) * 1980-02-04 1984-03-15 Landis & Gyr Ag Heizungsanlage.
DE3036640A1 (de) * 1980-09-29 1982-05-13 Georg Dipl.-Ing. 2000 Hamburg Clasen-Schulz Energiesparende schaltung von umwaelzpumpen bei heizungsanlagen
US4556077A (en) * 1983-12-20 1985-12-03 Allied Corporation Switching valve for a fuel supply system
SE457671B (sv) * 1984-02-17 1989-01-16 Lampert Heinz Anordning foer maetning av den vaermemaengd som avges till ett rum och reglering av rumstemperaturen
DE3701439C3 (de) * 1987-01-20 1994-07-28 Rolf Bommer Verfahren zum Betreiben eines Heizkessels und nach diesem Verfahren betriebener Heizkessel
GB9014386D0 (en) * 1990-06-28 1990-08-22 Electricity Ass Services Ltd Controlling air conditioning systems
DE4426401A1 (de) 1994-07-26 1996-02-08 Baelz Gmbh Helmut Warmwasserheizungssystem
DE102008028375A1 (de) 2008-06-13 2009-12-17 Solarnext Ag Verfahren und Einrichtung zum Regeln des Volumenstroms eines Übergabemediums einer Heiz- oder Kühlanlage

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US2344555A (en) * 1941-12-31 1944-03-21 Honeywell Regulator Co Heating and cooling system
US2490932A (en) * 1945-05-31 1949-12-13 Honeywell Regulator Co Control apparatus
US3236292A (en) * 1962-11-15 1966-02-22 Hupp Corp High temperature heating apparatus

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US2344555A (en) * 1941-12-31 1944-03-21 Honeywell Regulator Co Heating and cooling system
US2490932A (en) * 1945-05-31 1949-12-13 Honeywell Regulator Co Control apparatus
US3236292A (en) * 1962-11-15 1966-02-22 Hupp Corp High temperature heating apparatus

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3873022A (en) * 1972-06-14 1975-03-25 Tour Agenturer Ab Regulating station
US3999598A (en) * 1974-02-22 1976-12-28 Suddeutsche Kuhlerfabrik, Julius Fr. Behr Water temperature regulator
US4050626A (en) * 1975-04-18 1977-09-27 Awalt Jr Thomas Y Supplemental heat and heat transfer subsystems for solar air conditioning systems
US4207866A (en) * 1977-09-15 1980-06-17 Boyd Rodney E Solar heating system including freeze protection
US4388964A (en) * 1979-10-11 1983-06-21 Arthur D. Little, Inc. Thermal control system
US4700548A (en) * 1986-03-05 1987-10-20 Ontario, Inc. Control apparatus for ice rink refrigeration equipment
EP0374424A1 (en) 1988-11-30 1990-06-27 General Electric Company Silicon infiltrated porous polycrystalline diamond compacts and their fabrications
DE4002502A1 (de) * 1989-02-02 1990-08-09 Vaillant Joh Gmbh & Co Wasserheizungsanlage
US6732791B2 (en) * 1999-12-31 2004-05-11 Stac, Inc. Hydraulic oil cooler and supplying vessel pressure stabilizer
US20100212604A1 (en) * 2007-05-10 2010-08-26 Kyungdong Navien Co., Ltd. Hot water supplying system
US8117998B2 (en) * 2007-05-10 2012-02-21 Kyungdong Navien Co., Ltd. Hot water supplying system
US8285129B2 (en) * 2008-06-24 2012-10-09 Kyungdong One Corporation Hot water supply system for constantly maintaining temperature of hot water
US20100329650A1 (en) * 2008-06-24 2010-12-30 Yong-Bum Kim Hot water supply system for constantly maintaining temperature of hot water
US20100326646A1 (en) * 2008-06-27 2010-12-30 Yong-Bum Kim Method for controlling a hot water temperature using low flux in hot water supply system
CN101922760A (zh) * 2010-09-01 2010-12-22 余志锋 热水器出水管路冷水回用装置
CN101922760B (zh) * 2010-09-01 2012-11-28 余志锋 热水器出水管路冷水回用装置
US20150136377A1 (en) * 2013-11-19 2015-05-21 Grundfos Holding A/S Method for a heat transfer system and heat transfer system
RU2675438C2 (ru) * 2013-11-19 2018-12-19 Грундфос Холдинг А/С Способ управления для системы передачи теплоты, а также такая система передачи теплоты
US10690423B2 (en) * 2013-11-19 2020-06-23 Grundfos Holding A/S Method for a heat transfer system and heat transfer system
US20160305671A1 (en) * 2013-12-05 2016-10-20 Zonealone Limited A domestic hot water installation
US10527297B2 (en) * 2013-12-05 2020-01-07 Systemlink Aquaeco Limited Domestic hot water installation
CN108139084A (zh) * 2015-10-02 2018-06-08 格兰富控股联合股份公司 液压系统
US10830458B2 (en) 2015-10-02 2020-11-10 Grundfos Holding A/S Hydraulic system
US20230109989A1 (en) * 2021-10-07 2023-04-13 Accademia Europea Bolzano - Eurac Research Regulation system for a thermo-hydraulic circuit and control method
US12140977B2 (en) * 2021-10-07 2024-11-12 Accademia Europea Bolzano—Eurac Research Regulation system for a thermo-hydraulic circuit and control method

Also Published As

Publication number Publication date
GB1233647A (xx) 1971-05-26
DE1965938A1 (de) 1970-11-12
CH510237A (de) 1971-07-15
NL6909026A (xx) 1969-12-17
BE734567A (xx) 1969-12-15
DE1928575B2 (de) 1971-03-11
SE351482B (xx) 1972-11-27
DE1928575A1 (de) 1970-02-05
FR2010967A1 (xx) 1970-02-20

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