Classifications

• • 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
  • F24D12/00—Other central heating systems
  • F24D12/02—Other central heating systems having more than one heat source
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
  • F01K17/00—Using steam or condensate extracted or exhausted from steam engine plant
  • F01K17/02—Using steam or condensate extracted or exhausted from steam engine plant for heating purposes, e.g. industrial, domestic
• • 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
• • 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
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/04—Gas or oil fired boiler
  • F24D2200/043—More than one gas or oil fired boiler
• • Y—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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
• • Y—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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

• the present disclosure generally relates to modulation control of various systems utilizing one or more energy sources for a particular purposes, such as, for example, systems utilizing natural gas, oil, coal, gasoline, steam, water and/or electricity for purposes of providing heating, cooling, pumping, current output and/or mechanical energy.
• the present invention specifically relates to a load based modulation control of such systems.
• thermonic heating systems are used in buildings to supply heat via hot water that is circulated by a pump.
• One type of traditionally common heating system utilizes non-condensing boilers in which a portion of the input heat is lost via the boiler flue.
• a more modern type of heating system increases overall efficiency by employing condensing boilers.
• a condensing boiler recovers a large amount of heat from exhaust gases that would otherwise be lost via the flue.
• the temperature of the gases exiting the flue may be reduced from a range of 300° F-450° F to a range of 90° F- 130° F.
• Figure 1 is a schematic and block diagram of an embodiment of the present disclosure, illustrating a hybrid heating system having two boilers.
• Figure 2 is a schematic and block diagram of an embodiment of the present disclosure, illustrating a hybrid heating system having four boilers.
• Figure 3 is a schematic and block diagram of the main control circuit used in a heating system constructed in accordance with an embodiment of this disclosure.
• Figure 4 is a schematic and block diagram of condensing boiler control circuitry used in a heating system constructed in accordance with an embodiment of this disclosure.
• Figure 5 is a schematic and block diagram of non-condensing boiler control circuitry used in a heating system constructed in accordance with an embodiment of this disclosure.
• Figure 6 is a schematic and block diagram of a pH measurement control circuit used in a heating system constructed in accordance with an embodiment of this disclosure.
• Figure 7 is a schematic and block diagram illustrating a number of temperature sensor circuits, as well as a user interface circuit used in a heating system constructed in accordance with an embodiment of this disclosure.
• Figure 8 is a flowchart representative of a process modulation algorithm in accordance with an embodiment of this disclosure.
• Figure 9 is a flowchart representative of a rate-of-change modulation scheme in accordance with an embodiment of this disclosure.
• Figure 10 is a schematic and block diagram of a single system controller for a plurality of devices constructed in accordance with an embodiment of this disclosure.
• Figure 11 is a schematic and block diagram of a system administrator and corresponding device controllers for a plurality of devices constructed in accordance with an embodiment of this disclosure.
• FIG. 1 there is shown a hydronic (i.e., hot water) heating system 20 that includes boilers 21 and 22 for heating water that is circulated in order to heat a building.
• a hydronic heating system 20 that includes boilers 21 and 22 for heating water that is circulated in order to heat a building.
• Boilers 21 and 22 may both be condensing or non- condensing boilers, or one boiler may be a condensing boiler while the other is a non-condensing boiler. Boilers 21 and 22 are respectively associated with pumps 23 and 24 that act to provide circulation of the heated water throughout the building. Controller 36 is operably connected to boilers 21 and 22 via connectors 42 and 43 respectively. Connectors 42 and 43 are illustratively shown as being a cable or wire, but connectors 42 and 43, as well as other connectors described and shown herein, may take the form of an apparatus or functionality consistent with any technology known to those skilled in the art and appropriate for the purpose and application described (e.g., wireless transmission technology).
• Controller 36 provides signals that control the operation of boilers 21 and 22, including the operation of their respective boiler pumps 23 and 24.
• a temperature sensor 25 is located to measure the water temperature in boiler inlet or return water line 27 of boiler 21. Temperature sensor 25 is operably connected to controller 36 via connector 32. Temperature sensor 26 is located to measure the water temperature in outlet or system supply water line 28 of boiler 21 and is operably connected to controller 36 via connector 33. Similarly, a temperature sensor 29 is located to measure the water temperature in inlet or return water line 31 of boiler 22. Temperature sensor 29 is operably connected to controller 36 via connector 34. Temperature sensor 30 is located to measure the water temperature in outlet or system supply water line 32 of boiler 22 and is operably connected to controller 36 via connector 35.
• Water lines 27, 28, 31 and 32 are connected to the main circulating water line 37 that circulates heated water through heat transmission devices 18 and 19 (e.g., heat exchangers, radiators, or air handlers) located at various points throughout the building to heat the building.
• heat transmission devices 18 and 19 e.g., heat exchangers, radiators, or air handlers
• Auxiliary pumps 38 and 39 are connected to main water line 37 to assist the water flow. Pumps 38 and 39 are connected via connectors 40 and 41, respectively, to controller 36 to provide control of pumps 38 and 39.
• Water flow direction in heating system 20 is indicated by arrows 95 in Figure 1.
• Additional temperature sensors 44, 45, and 46 are located along main water line 37 to measure the temperature of the water at that location, and return the temperature data via data lines 47, 48, and 49, respectively, to controller 36, although it is understood that temperature data may be returned in a non- wired manner, e.g., wireless transmission, as would be known to those skilled in the art.
• Sensor 44 is illustratively shown as being located in the vicinity of the outgoing heated water from boilers 21 and 22, respectively.
• Sensor 45 is illustratively shown as being located in between boilers 21 and 22 to measure water temperature in the return portion of main water line 37.
• Sensor 46 is illustratively shown as being located in the return water flow from heat transmission devices 18 and 19 to boilers 21 and 22.
• An outside air temperature sensor 50 is connected to controller 36 via data line 51 to provide measurements of outside air temperature to controller 36 of heating system 20.
• Air temperature sensors 80 and 81 are illustratively shown as being connected to controller 36 via connectors 82 and 83, respectively. Air temperature sensors 80 and 81 are illustratively located in rooms or areas of the building to be heated, and provide data to controller 36 regarding the ambient temperature of those rooms or areas.
• Dampers 52 and 53 are illustratively shown as being controlled via connectors 54 and 55, respectively, by controller 36 for controlling outside air flow to boilers 21 and 22, respectively, in order to provide free air make-up to boilers 21 and 22.
• Flow valves 56, 57, 58, and 62 are illustratively shown as being connected to and controlled by controller 36 via connectors 59, 60, 61, and 63, respectively.
• the rate and quantity of soft or conditioned water supplied to flush by-pass or sidestream water line 64 via incoming water line 70, in order to maintain calibration of pH meter 67 located in sidestream water line 64, is controlled by way of flow valves 57 and 58.
• Water is drained from main water line 37 via drain line 17 by way of flow valves 56 and 58.
• pH meter 67 measures the pH of the water within main water line 37.
• Main valve 75 is located within main water line 37 and is illustratively shown as being connected to controller 36 by connector 76 to force water flow through sidestream water line 64.
• Connector 71 connects pH meter 67 to controller 36.
• Flow measuring device 65 is mounted to main water line 37 and provides flow data via connector 66 to controller 36.
• a user interface 90 e.g., computer input screen, is illustratively shown as being connected to controller 36 by way of connector 91.
• Heating system 120 illustratively includes non-condensing boilers 121 and 122 and condensing boilers 123 and 124 connected to a main water circulation line 147 by inlet or boiler return water lines 126, 127, 128, and 129, respectively and outlet or system supply water lines 130, 131, 132, and 133, respectively.
• Boilers 121, 122, 123, and 124 are respectively associated with pumps 134, 135, 136, and 137 which are mounted on the boiler return water lines 126, 127, 128, and 129, respectively.
• Pumps 134, 135, 136, and 137 are preferably enabled with variable frequency drive circuitry that allows the pumps to be operated at variable speeds, i.e., pumping rates.
• heating system 120 of Figure 2 includes temperature sensors 138, 140, 142, and 144 mounted on the outlet or system supply water lines 130, 131, 132, and 133, respectively, and temperature sensors 139, 141, 143, and 145 mounted on the inlet or return water lines 126, 127, 128, and 129, respectively.
• Boilers 121, 122, 123, and 124 are operably connected to controller 146 via connectors 221, 222, 223, and 224, respectively.
• Pumps 134, 135, 136, and 137 are operably connected to controller 146 via connectors 234, 235, 236, and 237, respectively.
• Temperature sensors 138, 139, 140, 141, 142, 143, 144, and 145 are operably connected to a controller 146 via connectors 238, 239, 240, 241, 242, 243, 244, and 245, respectively.
• Figure 2 shows controller 146 connected to the various components herein described via hard wired control or connection lines or wires, it will be understood that various wireless connections are envisioned including, but not limited to, IR, RF, and optical links.
• Boilers 121, 122, 123, and 124 include air dampers 148, 149, 150, and 151, which are also operably connected to controller 146 via connectors 248, 249, 250, and 251, respectively.
• Controller 146 may independently control the operation of air dampers 148, 149, 150, and 151 via switching or control signals, e.g., digital signals, sent to dampers 148, 149, 150, and 151 via connectors 248, 249, 250, and 251 to control the outside or free air make-up to boilers 121, 122, 123, and 124, respectively.
• Auxiliary pumps 152 and 153 pump or circulate water through secondary water line 154 of main water line 147 and are operated by controller 146 via connectors 252 and 253, respectively.
• Auxiliary pumps 155 and 156 pump or circulate water through secondary water line 157 and are operated by controller 146 via connectors 255 and 256, respectively.
• Water flow direction through system 120 is illustratively shown by arrows 200.
• Valves 167 and 170 are connected to and controlled by controller 146 via connectors 267 and 270, respectively, to provide soft or conditioned water via inlet line 168 to flush sidestream 185 as necessary to maintain the calibration of pH meter 172.
• Controller 146 is also operably connected to sidestream valves 166 and 169 via connectors 266 and 269, respectively, to control the flow of water from main water line 147 to a pH measurement sidestream water line 185.
• a pH meter 172 is provided to measure the pH of the water circulating throughout system 120. pH meter 172 is shown as being mounted in pH measurement sidestream 185 and operably connected to controller 146 via connector 272.
• Main valve 165 is mounted within main water line 147 and is also operably connected to controller 146 via connector 265.
• Controller 146 operates main valve 165 to force the flow of water through pH measurement sidestream 185.
• a weak acid pump 195 and a weak base pump 196 are illustratively shown as being coupled into main water line 147.
• Acid pump 195 and base pump 196 are shown as being operably connected to controller 146 via connectors 295 and 296, respectively. Controlling the pH of the water circulating through main water line 147 is important to prevent premature failure or wear with respect to the components of heating system 120 due to overly acidic or basic water.
• valves 165, 166, 167, 169, and 170 by controller 146 by signals via connectors 265, 266, 267, 269, and 270, respectively, periodic checks of the pH of the water in main water line 147 can be made by diverting some water into sidestream 185 and measuring its pH by pH measurement sensor 172 and returning that data to controller 146 via connector 272. If the water requires an adjustment of its pH, controller 146 can initiate the operation of weak acid pump 195 or weak base pump 196 by signals sent via connectors 295 or 296, respectively, as needed to restore the pH of the water in main water line 147 to a satisfactory level.
• Temperature sensors 160, 161, and 162 are mounted to main water line 147 to measure the temperature of the circulating water at various locations along main water line 147. Sensors 160, 161, and 162 are shown as being operably connected to controller 146 via connectors 260, 261, and 262, respectively. A flow measuring device 163 is shown as being mounted on main water line 147 to provide water flow information to controller 146 via connector 263. An outdoor air temperature sensor 164 is mounted outside the building and is operably connected to controller 146 via connector 264. Air temperature sensors 180 and 181 are located in rooms or areas of the building and are also operably connected to controller 146 via connectors 280 and 281, respectively, to provide information with respect to the ambient temperature of the rooms or areas in which the sensors are located.
• Figure 2 illustratively shows heat transmission devices 201 and 202 located within system 120.
• Devices 120 may be end user heat distribution apparatus, such as radiators, heat exchangers, or air handlers, for only a few examples.
• a user interface device 190 is also operably connected to controller 146 via connector 290 to allow a user of heating system 120 to select or change various input criteria, e.g., desired room temperature, or the manner in which heating system 120 is operated.
• User interface device 190 also provides a means for information regarding the status or condition of the components of system 120 to be communicated to the user.
• main water line 37 shown in Figure 1 and main water line 147 shown in Figure 2 locates the condensing boilers 123 and 124 upstream from the non-condensing boilers 121 and 122 such that during the time the condensing boilers are enabled, their operation will pre-heat the water flowing to the non-condensing boilers, thereby increasing the efficiency of the non- condensing boilers and acting to prevent the non-condensing boilers from condensing, thereby protecting the non-condensing boilers from the detrimental effects of condensation.
• the present disclosure does not limit the number or types of boilers that can be used within a heating system.
• Figures 3-7 which, for example only, illustrate elements of a hydronic heating system that includes two condensing and two non-condensing boilers in an arrangement such as that shown in Figure 2.
• Figure 2 Reference will therefore be made primarily to Figure 2, although it is understood that the principles of operation to be described apply equally to heating systems having different numbers of boilers, including but not limited to the system of Figure 1.
• Figures 3 illustrates the presence of a main system controller and its associated input and output signals and functions.
• Figure 4 illustrates the presence of a condensing boiler controller and its associated input and output signals and functions.
• Figure 5 illustrates a non-condensing boiler controller with its associated input and output signals and functions, and
• Figure 6 illustrates a pH measurement controller and its associated input and output signals and functions.
• a unitary controller such as controller 36 or 146, may comprise the functionality of each of the controller elements shown in Figures 3-6 in the physical embodiment of a single device. Therefore, for purposes of simplifying the following explanation, each of the controller devices in Figures 3-6 will be identified by reference number 146.
• Figures 3-7 may illustrate elements that contain language that suggests a function or type of information, that element may be identified by a reference number that corresponds to the physical device shown in Figure 2 that performs such function or provides such information.
• Figure 7 illustrates a representation of the functionality within heating system 120 of user interface 190 as well as a number of representative temperature sensors, e.g., sensors 160, 164, 180, and 181. Through the use of user interface device 190, the type of each boiler 121-
• the outdoor air temperature switch point i.e., the temperature above which a condensing-type boiler is initially selected, may also be provided to system 120 via user interface device 190.
• controller 146 Using data provided by interface device 190, and the outdoor air temperature provided by sensor 164 via connector 264, controller 146 will enable at least one of pumps 134-137 via their respective connectors 234-237. After a user defined delay (e.g., 1 to 10 minutes), a flow reading using flow sensor 163 in the main water line 147 will be taken.
• controller 146 uses this flow data provided via connector 263, as well as other initializing data, controller 146 calculates an initial building heating load for system 120. Based on this calculated load and the outdoor air temperature switch point, controller 146 will determine which type of boiler (e.g., condensing or non-condensing) to initially enable. For example, if the outdoor air temperature calls for a condensing boiler and there is more than one condensing boiler available in system 120, then the first boiler selected can be based on which one has accumulated the least hours of operation. This may be done by comparing timers linked with each boiler's respective output enable circuits, unless a particular boiler in the system has been designated a dedicated lead boiler, in which case it will always be enabled or fired first.
• type of boiler e.g., condensing or non-condensing
• controller 146 may also select for operation the boiler having an output that is most closely matched to the building load. If the condition should exist that a particular boiler is in an alarm state (i.e., the boiler is not working properly), controller 146 will not enable that boiler until the condition causing the alarm is remedied. For purposes of this example, condensing boiler 124 is initially enabled by controller 146 via connector 224. After an initial period of low fire output of boiler 124, the building heating load will be recalculated to obtain a real-time heating load.
• This low fire time delay e.g., 30 minutes, is used to ensure that the initial calculated heating load is accurate so as to avoid overshooting the desired building temperature by overfiring the initially enabled or fired boiler or boilers. If the recalculated heating load indicates that heat is still required, the initially enabled boiler 124 will thereafter by operated in its normal or real-time mode, e.g., via proportional- integral-derivative (PID) control, by controller 146 via connector 224. The operation of the PID mode of controller 146 will be constantly monitored.
• PID proportional- integral-derivative
• controller 146 causes the output of boiler 124 to remain above a user defined output percentage (e.g., 25%-100%) for a given user defined time period (e.g., 5-60 minutes), then a second boiler, e.g., condensing boiler 123, will be enabled via connector 223 and controller 146 will split the real time heating load between the two enabled boilers 124 and 123 in a manner that operates both boilers as efficiently as possible.
• the heating load distribution between boilers 124 and 123 is monitored often (e.g., once per second) to ensure boilers 124 and 123 continue to be operated as efficiently as possible.
• boilers 124 and 123 have been operating at a user defined maximum output for a user defined period of time and a user defined heating load percentage (e.g., 1- 10%) has not been reached, a non-condensing boiler, e.g., boiler 122 will then be enabled by an enabling signal via connector 222.
• a non-condensing boiler e.g., boiler 122 will then be enabled by an enabling signal via connector 222.
• non-condensing boiler 122 Once non-condensing boiler 122 has been enabled, condensing boilers 124 and 123, that are still enabled, will be reset to cover that portion of the heating load that still allows non-condensing boiler 122 to maintain its minimum recommended return water temperature. Non- condensing boiler 122 will operate under PID control to cover the balance of the heating load. Should the heating load increase, the non-condensing boilers will follow the same sequencing control described above to enable and control additional non-condensing boilers, e.g., boiler 121, and boiler pumps, e.g., pump 134.
• additional non-condensing boilers e.g., boiler 121
• boiler pumps e.g., pump 134.
• building zone temperatures will be polled by network temperature devices, e.g., sensors 180 and 181, to determine if the output (i.e., supply temperature) of system 120 is meeting the heating load. Based on this information, boiler reset temperatures will be increased to supply more heat if needed, decreased to increase efficiency of boiler operation, or left the same.
• This polling enables controller 146 to know how much energy has been used to heat the building and, based on the calculated heating load, enable only the boiler or boilers needed to most efficiently meet the remaining heating load.
• condensing boilers 124 and 123 will be shut down by controller 146 by signals provided via connectors 224 and 223, respectively.
• Condensing boilers 124 and 123 will be enabled again only if the return water temperature of non- condensing boilers 121 and 122 (if enabled) falls below a user defined limit (e.g., 130 0 F) and remains there for more than a user defined period of time (e.g., 5-30 minutes), or if the outdoor air temperature rises above the condensing/non- condensing switch point, or if all the non-condensing boilers, in this case boilers 121 and 122, are operating at a user defined maximum output for a user defined period of time (e.g., 15-60 minutes) and have failed to adequately satisfy the heating load.
• a non-condensing boiler will be shut down by controller 146.
• Boiler operating regulations require that a boiler must be shut down at least once every 24 hours.
• system 120 operates such that each boiler 121-124 is shut down at least once every six hours.
• This process allows controller 146 to regularly compare hours of accumulated operation and enable or fire the boiler of a given type with the least operating hours first. If the heating load of the building is determined to be less than the minimum operating range of all the available boilers 121-124 on system 120, controller 146 will select and enable the boiler having the lowest operating range. This functionality of controller 146 will help to eliminate as much as possible the efficiency losses and significant wear effects of short cycling on boilers 121-124.
• any condensing boilers e.g., boiler 123 or 124
• any condensing boilers e.g., boiler 123 or 124
• the total load will then be assigned to the running non-condensing boiler and the reset of the supply or output temperature will be defined by an equation having a slope which is designated for non-condensing boilers.
• the inlet and outlet temperature difference i.e., ⁇ T
• ⁇ T is a user defined value (e.g., 10° F-45° F or within the boiler manufacturer's limits) that can be selected via user interface device 190.
• This ⁇ T measured by temperature sensors 144 and 145 for boiler 124, for example, is maintained to the extent possible via operation of controller 146 by providing control signals to the variable frequency drives of the boiler's respective pump, e.g., pump 137 in the above example.
• Pump 137 for example, will then be modulated or operated to increase or decrease water flow so as to maintain the measured ⁇ T with the user selected value.
• the pumps can put out less water at higher temperatures, thereby increasing boiler efficiency.
• system 120 provides microprocessor control of differing types of boilers in a heating system through the use of a variety of sensor inputs to optimally sequence and operate each boiler in the heating system to maximize efficiency of the boilers.
• the system is suitable for controlling multiple boilers of different sizes and of different types within the same heating system. By calculating real time heating load and using that information to select and operate boilers, efficiency losses and detrimental effects on equipment life due to short-cycling of boilers are prevented or eliminated.
• the system disclosed herein effectively prevents non-condensing boilers from condensing while condensing boilers are allowed to condense.
• the system offers the ability to reset and control both condensing and non-condensing boilers on the same system. With two unique and user definable reset temperature slopes, both types of boilers can be utilized seamlessly.
• FIGS. 3-6 were described in the context of implementing a PID version of a process modulation algorithm of the present invention for purposes of controlling a hybrid boiler system.
• the process modulation algorithm is applicable to many types of systems including, but not limited too, systems employing devices using energy sources (e.g., natural gas, oil, coal, gasoline, steam, water and electricity) for any purpose (e.g., heating, cooling, pumping, current output and mechanical energy).
• energy sources e.g., natural gas, oil, coal, gasoline, steam, water and electricity
• any purpose e.g., heating, cooling, pumping, current output and mechanical energy.
• a description will now be provided herein of a flowchart 300 representative of the process modulation algorithm as shown in FIG. 8 and a description of a flowchart 400 representative of the rate-of-change modulation version of the process modulation algorithm as shown in FIG. 9.
• a stage S302 of flowchart 300 encompasses a system load calculation that is dependent upon one or more operational conditions (e.g., temperature, pressure, power consumption, motion, etc.) of an applicable system (e.g., heating, cooling, pumping, current output and mechanical energy).
• operational conditions e.g., temperature, pressure, power consumption, motion, etc.
• an applicable system e.g., heating, cooling, pumping, current output and mechanical energy.
• the following equations [1] and [2] can be utilized for purposes of calculating a system load for the hybrid heating system that is dependent upon a set-point temperature of the hybrid heating system:
• L ((T SP -T R )+(T SP -T S )+(CTL-T R ))*(GPM*WLG*MPH) [2]
• L is a calculated system load (BTU/H) for the hybrid heating system
• T S p is the set-point temperature ( 0 F) of the hybrid heating system
• Ts is the supply water temperature ( 0 F) of the hybrid heating system
• T R is the return water temperature ( 0 F) of the hybrid heating system
• GPM is the number of gallons per minute flowing through the hybrid heating system past a flow sense point
• WLG is the pounds of water per gallon within the hybrid heating system
• MPH is the minutes per hour the hybrid heating system is expected to be operational for an hour time period
• CTL is a condensing temperature limit ( 0 F) of the hybrid heating system.
• Equation [1] is utilized for all condensing operations and for non- condensing operations whereby the return water temperature T R is equal to or greater than the condensing temperature limit CTL.
• equation [2] is utilized for non-condensing operations whereby the return water temperature T R is less than the condensing temperature limit CTL.
• a hybrid heating system can be switched between condensing operations and non- condensing operations based on a comparison of the outdoor air temperature to a switch temperature point whereby condensing operations primarily occur above the switch temperature point and non-condensing operations primarily occur below the switch temperature point.
• a determination of the set-point temperature is also dependent upon whether the hybrid heating system is in condensing operations or non-condensing operations.
• a condensing reset temperature slope is derived from a graph of a water temperature range and output air temperature range for the condensing boiler(s). For this slope, one endpoint is plotted as the maximum water temperature/minimum outdoor air temperature and the other endpoint is plotted as the minimum water temperature/maximum outdoor air temperature whereby the set-point temperature is the water temperature on the slope corresponding to a sensed outdoor air temperature.
• a non-condensing reset temperature slope is derived from a graph of a water temperature range and output air temperature range for the non-condensing boiler(s).
• a stage S304 of flowchart 300 encompasses a device load assignment that is dependent upon the output capacities of the device(s) (e.g., boilers, chillers, pumps, dampers, etc.) of the applicable system (e.g., heating, cooling, pumping, current output and mechanical energy).
• the device(s) e.g., boilers, chillers, pumps, dampers, etc.
• the applicable system e.g., heating, cooling, pumping, current output and mechanical energy
• BY IL is a load assignment (BTU/H) for a particular boiler Y
• OY MAX is the maximum output (BTU/H) for a particular boiler Y
• ⁇ OX MAX is a summation of all maximum outputs (BTU/H) for the enabled boilers X
• OY MIN is the minimum output (BTU/H) for a particular boiler Y
• ⁇ OX MIN is a summation of all minimum outputs (BTU/H) for the enabled boilers X
• Equation [3] is utilized whenever all of the control signal(s) (e.g., analog or digital, voltage or current) of the enabled boiler(s) X are to be modulated as subsequently described herein.
• equation [4] is utilized whenever less than all of the control signal(s) (e.g., analog or digital, voltage or current) of the enabled boiler(s) X are to be modulated as subsequently described herein.
• the determination of which boiler(s) to enable at any given moment is a function of the operational state of the system (i.e., condensing or non-condensing) as well as the operational state of each boiler in terms of at least an online/offline status of the boiler, and an operational time status of the boiler.
• Stages S302 and S304 are initially executed prior to the conclusion of the low fire time delay of the hybrid heating system and thereafter are continually executed on a periodic basis to maintain a dynamic efficient control of the hybrid heating system. Still referring to FIG. 8, a stage S306 of flowchart 300 encompasses a device output error calculation that is based on a comparison of an assigned device load and a device output for each enabled device (e.g., boiler, chiller, pump, damper, etc.) of the applicable system (e.g., heating, cooling, pumping, current output and mechanical energy).
• enabled device e.g., boiler, chiller, pump, damper, etc.
• BYsp is the boiler output set-point temperature (BTU/H) for a particular boiler Y
• BY 1L is the previously calculated load assignment (BTU/H) for a particular boiler Y
• BY HL is a high limit for the boiler output set-point temperature BY S p
• BY LL is a low limit for the boiler output set-point temperature BYsp
• OY MAX is the maximum output (BTU/H) for a particular boiler Y
• OY MIN is the minimum output (BTU/H) for a particular boiler Y
• DB is a deadband based on an output percentage factor OPF of a particular boiler Y whereby the output percentage factor OPF can be designed to range from 1 to 100,
• O BY is a calculated heat output (BTU/H) for a particular boiler Y
• VcoN is an analog control voltage signal for a particular boiler Y that controls the fire level of that boiler Y
• V MAX is a maximum of the analog control voltage signal V CON (e.g., 10
• V MIN is a minimum of the analog control voltage signal V CON (e.g., 0 volts)
• E ⁇ is the calculated error for a particular boiler Y. While equations [5]-[10] can be executed during the low fire time delay of the hybrid heating system, it is only essential for equations [5]-[8] to be executed or processed during the flow fire time delay and all of the equations [5]-[10] to be executed continually on a periodic basis upon completion of the low fire time delay.
• the boiler output set-point temperature BY S p is a function of the calculated load assignment BY IL that can dynamically vary between the low limit BY LL and the high limit BY HL - AS such, those having ordinary skill in the art will appreciate the purpose of utilizing the deadband DB to establish the low limit BY LL and the high limit BY HL is to limit the dynamic variable nature of the calculated load assignment BY IL .
• the output percentage factor OPF is preferably 1 for stage S306.
• stage S308 encompasses a modulation of an output of a device
• a modulation scheme chosen for an applicable system e.g., heating, cooling, pumping, current output and mechanical energy.
• a modulation of an output of an enabled boiler based on a calculated device output error of that enabled boiler is in accordance with PID modulation scheme previously described herein.
• the chose modulation scheme is a rate- of-change modulation scheme as represented by the flowchart 400 shown in FIG. 9.
• a stage S402 of flowchart 400 encompasses a calculation of a modulation control variable.
• CV Y is the modulation control variable for a particular boiler Y that varies between a low limit CV LL and a high limit CV HL (initially equal to low limit CV LL upon the enablement of the boiler)
• E ⁇ is the calculated error for a particular boiler Y
• ADCF is an analog-to-digital conversion factor corresponding to a number bit states of a digital analog voltage signal AN Y divided by the maximum voltage V MAX for the analog control voltage signal V CON -
• the purpose of utilizing the deadband DB to control the calculation for the modulation control variable CV Y is to limit the dynamic variable nature of the calculated error E ⁇ , which is a function of the dynamic variable nature of calculated load assignment BY IL .
• the output percentage factor OPF is preferably 1 for stage S402.
• the following equation [18] can be utilized to prevent an oversaturation of the modulation control variable CV Y :
• a stage S404 of flowchart 400 encompasses a calculation of a control signal for each enable device (e.g., boiler, chiller, pump, damper, etc.) of the applicable system (e.g., heating, cooling, pumping, current output and mechanical energy) as a function of the previously calculated modulation control variable CVy.
• each enable device e.g., boiler, chiller, pump, damper, etc.
• the applicable system e.g., heating, cooling, pumping, current output and mechanical energy
• R PG1 is the base biased ramp down variable for a particular boiler Y
• V G is the water volume of a particular boiler Y in gallons
• B E is a maximum rated efficiency of a particular boiler Y
• OY MAX is the maximum output (BTU/H) for a particular boiler Y
• R PG2 is the amplified biased ramp down variable for a particular boiler Y.
• the output percentage factor OPF for deadband DB is 5 for the biased ramp down of digital control voltage signal AN Y .
• the following equation [28] can be utilized to control a timer gate that counts up to allow a calculation of digital control voltage signal ANy and is thereafter reset to begin a new count up sequence for the next calculation of digital control voltage signal ANy:
• TPGVY is a timer gate preset value
• PA is a process acceleration scale value
• TGF is a time gate factor inversely correlated to a chosen output percentage factor OPF for deadband DB.
• the inverse correlation of the timer gate factor TGF and the output percentage factor OPF is a function of the timing specification of the timer gate and one or more designed output percentage factors OPF for deadband DB.
• the following table illustrates an inverse correlation designed output percentage factors to a timer gate factor TGF in terms of the number times per second the timer gate should allow for a calculation of the digital control voltage signal ANy
• Equation [28] The benefit of equation [28] is as the calculated error Ey of stage 306 decreases, the rate-of-change of the modulation of the digital control voltage signal ANy is decelerated in view of a corresponding increase in the timer gate preset value TPGVY. Conversely, as the calculated error Ey of stage 306 increases, the rate-of-change of the modulation of the digital control voltage signal ANy is accelerated in view of a corresponding decrease in the timer gate preset value TPGVY.
• flowchart 400 is designed to execute digital calculations of the modulation control variable and digital control voltage signal and thus the requirement for equations [16] and [17].
• the digital control voltage signal has to be converted back into the analog control voltage signal.
• FIGS. 8 and 9 those having ordinary skill in the art will appreciate the benefits of the process modulation algorithm and various modulation schemes of the present invention.
• Those having ordinary skill in the art of the present invention will further appreciate how to apply equations [l]-[28] to various systems, in particular how to design the various variables of equations [l]-[28] in view of the particular type of devices to be controlled in accordance with the present invention. For example, FIG.
• FIG. 10 illustrates a system controller 500 for implementing flowcharts 300 (FIG. 8) and 400 (FIG. 9) via a wireline or wireless network with an X number of devices 600 of any type (e.g., boilers, chillers, pumps, dampers, etc.).
• FIG. 11 illustrates a system administrator 501 for executing stages S302 and S304 of flowchart 300 (HG. 8) via a wireline or wireless network to device controllers 502 for executing stages S306 and S308 of flowchart 300 as well as flowchart 400 (FIG. 9) on behalf of devices 600 (e.g., boilers, chillers, pumps, dampers, etc.).
• administrator 501 can partially or entirely execute stage S306.

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• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Control Of Steam Boilers And Waste-Gas Boilers (AREA)
• Steam Or Hot-Water Central Heating Systems (AREA)

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• 2007
  • 2007-12-03 US US11/949,314 patent/US20080179416A1/en not_active Abandoned
• 2008
  • 2008-01-24 EP EP08713951A patent/EP2109740A4/de not_active Withdrawn
  • 2008-01-24 WO PCT/US2008/051846 patent/WO2008091970A2/en active Search and Examination
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