JP2005009781A - Output control device and output control method for cogeneration system - Google Patents

Output control device and output control method for cogeneration system Download PDF

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JP2005009781A
JP2005009781A JP2003174975A JP2003174975A JP2005009781A JP 2005009781 A JP2005009781 A JP 2005009781A JP 2003174975 A JP2003174975 A JP 2003174975A JP 2003174975 A JP2003174975 A JP 2003174975A JP 2005009781 A JP2005009781 A JP 2005009781A
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energy saving
amount
heat
cogeneration
time zone
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JP2003174975A
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Japanese (ja)
Inventor
Iwao Azuma
Hiroshi Yamamoto
啓 山本
岩男 東
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Chofu Seisakusho Co Ltd
株式会社長府製作所
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Priority to JP2003174975A priority Critical patent/JP2005009781A/en
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00Combustion technologies with mitigation potential
    • Y02E20/10Combined combustion
    • Y02E20/14Combined heat and power generation [CHP]
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/16Energy recuperation from low temperature heat sources of the ICE to produce additional power
    • Y02T10/166Waste heat recovering cycles or thermoelectric systems

Abstract

<P>PROBLEM TO BE SOLVED: To provide an output control technology for maximizing the energy saving performance of the whole cogeneration system including energy loss at the start or stop of a cogeneration device. <P>SOLUTION: This output control device is provided with a power generation plan storage means 34 for storing an energy saving amount or an energy saving degree, and a stop section determining means 35 for determining the stop of the cogeneration device in a continuous time zone section when the sum total of the energy saving amount or energy saving degree in the time zone section out of the continuous time zone section within a power generation planning period is smaller than the sum total of the energy saving amount or energy saving degree in the case of stopping the cogeneration device in the same time zone section. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an output control technique for performing output control of a cogeneration device so as to enhance energy saving in a cogeneration system that consumes electric power and heat output from a cogeneration device by an electric power load, a heating load, and a hot water supply load. .
[0002]
[Prior art]
In recent years, cogeneration systems have attracted attention as clean energy supply systems. A cogeneration system is an energy-saving system that generates heat that can be used effectively simultaneously with electricity and uses energy in multiple stages.
[0003]
At present, gas engine cogeneration systems, fuel cell cogeneration systems, and the like have been developed as cogeneration systems for general households, and some of them have already been put into practical use. A gas engine cogeneration system is a cogeneration system composed of a gas engine power generation unit, which is a cogeneration system, and a hot water heating / heating unit that uses exhaust heat, and exhaust heat exhausted from the gas engine that generates electricity. Is the main heat source of the waste heat utilization hot water supply / heating unit. The fuel cell cogeneration system generates hydrogen from a city gas supplied to each household using a fuel processing device, and uses this hydrogen to generate power in a fuel cell that is a cogeneration device. The exhaust heat is recovered and used for hot water supply and heating. Currently, a polymer electrolyte fuel cell (PEFC) has been developed as a fuel cell, and can generate power at a low temperature of 90 ° C. or lower.
[0004]
In such a cogeneration system, how to improve energy saving is an important issue. The cogeneration apparatus outputs energy in the form of electric power and heat. And since the output amount of this electric power and the amount of heat is uniquely determined by the amount of energy consumed by the cogeneration device, the output power and the output heat amount cannot be adjusted independently. Therefore, when the balance between the power demand and the heat demand in a certain time zone does not coincide with the balance between the output power and the output heat amount of the cogeneration apparatus, the excess heat amount is adjusted by storing heat. However, if the amount of stored heat is excessive, the amount of heat is not effectively used. Therefore, a cogeneration system output control technique is required to maximize the energy saving performance of the cogeneration system.
[0005]
As an output control technique of a conventional cogeneration apparatus, for example, the one described in Patent Document 1 is known. The cogeneration system described in Patent Document 1 includes a cogeneration device, a power distribution unit, a heat distribution unit, a measurement unit, a control unit, and a storage unit. The cogeneration apparatus outputs electric power and heat. This power is supplied to the facility by the power distribution means together with the received power from the power plant. The heat is supplied to the facility after the heat distribution means stores the heat. The measuring means measures the power and heat supplied to the facility, and stores them in the storage means such as a hard disk as the past power load record and heat load record of the facility.
[0006]
In such a cogeneration system, first, the predicted power load and predicted heat load of the facility at the planning target time of the operation plan are predicted from the past power load record and heat load record of the facility stored in the storage means. To do. Next, the thermal output of the cogeneration apparatus when the main operation of the cogeneration apparatus is performed on the predicted power load is derived. Here, “main operation” refers to rated operation when the predicted power load is sufficiently larger than the power output during the cogeneration rated operation, and the power output is always the power output in other cases. An operation method in which power follow-up operation is performed that is a certain amount smaller than the load.
[0007]
Then, the predicted integrated heat load, which is the integrated value at the planning target time of the predicted heat load, is compared with the integrated heat output, which is the integrated value during the operation time zone of the heat output, and the electric generator of the cogeneration system is compared at the planning target time. Determine the operating hours for driving. That is, the operation control means determines an operation time zone in which the main operation of the cogeneration apparatus is performed so that the predicted integrated heat load and the integrated heat output are equal at the planning target time.
[0008]
In this way, by operating the cogeneration apparatus as a main operator, the power output is controlled so as to always receive more than a certain amount of power from the power supplier, and reverse power flow to the power system is prevented. At the same time, the heat output from the cogeneration apparatus can be consumed as much as possible in the facility, and energy saving and economic efficiency can be improved.
[0009]
[Patent Document 1]
JP 2003-61245 A
[0010]
[Problems to be solved by the invention]
In the operation method of the conventional cogeneration apparatus, it is necessary to stop and start the cogeneration apparatus so that the predicted integrated heat load and the integrated heat output are equal at the planning target time of the operation plan.
[0011]
However, normally, when the cogeneration apparatus is stopped and started, extra energy used for stopping and starting operations is required. That is, for example, in the case of a fuel cell, electric power is generated by decomposing natural gas into hydrogen and carbon dioxide using a reformer and reacting the extracted hydrogen with oxygen (air). This reformer uses a catalyst to promote the decomposition reaction of natural gas, but it takes a relatively long time until the catalyst is sufficiently heated and the temperature is stabilized. Therefore, during this time, the fuel cell cannot generate power, and the operation only consumes energy. Further, after the power generation is stopped, it is necessary to cool the temperature of the catalyst of the reformer. For this cooling, it is necessary to operate a cooling pump for circulating the refrigerant for a certain period. Therefore, during this time, the operation is only to consume energy.
[0012]
Thus, when the cogeneration apparatus is stopped and started, the cogeneration apparatus becomes an energy load. Therefore, if the cogeneration apparatus is stopped only for a short time or if the operation and stop of the cogeneration apparatus are frequently repeated, the energy saving performance is deteriorated.
[0013]
On the other hand, in the conventional operation method of the cogeneration apparatus, since the energy loss at the time of starting or stopping of such a cogeneration apparatus is not considered, there is a problem that the result of improving the energy saving property is not always obtained. There is.
[0014]
Accordingly, an object of the present invention is to provide an output control technique for a cogeneration system that can maximize the energy saving performance of the entire cogeneration system, including energy loss when the cogeneration apparatus is started or stopped. There is.
[0015]
[Means for Solving the Problems]
The first configuration of the output control device of the cogeneration system according to the present invention consumes the electric power output by the cogeneration device that outputs electric power by power generation and outputs the amount of heat generated by the power generation, and the cogeneration device. A cogeneration system comprising: an electric power load; a heat storage device that stores the amount of heat output from the cogeneration device; and a heat load that consumes the amount of heat output from the cogeneration device or the amount of heat stored in the heat storage device. In the output control device for controlling the output of the cogeneration device, the power generation amount of the cogeneration device scheduled in each time zone within the power generation plan formulation period, and the power generation amount in each time zone Of the electricity and heat output by the cogeneration system That is, the value obtained by subtracting the effective energy consumption, which is the amount of power and heat that can be used by the power load and the heat load, from the primary energy consumption required when the effective energy consumption is covered by a commercial power source or a normal water heater. A power generation plan storage means for storing an energy saving amount, or an energy saving degree that is a value obtained by dividing the energy saving amount by the primary energy, or an energy saving index similar thereto (hereinafter referred to as “energy saving amount”); Among the continuous time zone sections within the power generation plan formulation period, the sum of the energy saving amount in the time zone section is more than the sum of the energy saving amount when the cogeneration device is stopped in the same time zone section. If it is smaller, a stop section determining unit that determines to stop the cogeneration apparatus in the continuous time zone section. Characterized in that it comprises a.
[0016]
With this configuration, when it is more advantageous from the standpoint of energy saving etc. to stop the cogeneration device in a continuous time zone within the power generation plan formulation period, it is more advantageous in terms of energy savings, etc. Decide to stop. Therefore, it is possible to improve the energy saving performance of the entire cogeneration system.
[0017]
Here, as the “heat storage device”, a stratified hot water storage tank, a latent heat storage tank using phase change, or the like is used. The “heat load” includes a hot water supply load by a hot water supply device, a heating load by a heater, and the like. The “power generation plan formulation period” refers to a period for formulating a plan for the power generation amount of the cogeneration system, and is usually one day, but is not limited thereto.
[0018]
According to a second configuration of the output control device of the cogeneration system according to the present invention, in the first configuration, the stop section determining means is a time slot in the time slot section in the power generation plan formulation period. A minimum energy saving section selecting means for selecting a minimum energy saving section that is a time zone section in which a total sum of the energy saving amount in the section is a minimum, and a total energy saving amount in the minimum energy saving section, and the lowest energy saving section The sum of the energy saving amount, etc., and the sum of the energy saving amount, etc. when the cogeneration device is stopped in the minimum energy saving interval are compared. If the former is smaller than the latter, the Stop determination means for determining to stop the generation device.
[0019]
Due to this configuration, the stop determination means saves energy by stopping the cogeneration system for continuous operation in the time zone where the total amount of energy savings, etc. is the smallest among the time zone within the power generation plan formulation period. When it is advantageous from the viewpoint of quantity or the like, the stop section determining means determines to stop the cogeneration apparatus. Therefore, frequent stop / start of the cogeneration apparatus is prevented. Therefore, it is possible to avoid a failure of the cogeneration apparatus due to frequent stop / start.
[0020]
In addition, if the power generation plan formulation period is set to one day (24 hours), it is more advantageous to execute either continuous operation of the cogeneration system or DSS (Daily Start and Stop) operation. It is possible to make a reasonable decision based on the predicted amount.
[0021]
The first configuration of the output control method of the cogeneration system according to the present invention consumes the electric power output by the cogeneration apparatus that outputs electric power by power generation and outputs the amount of heat generated by the power generation, and the cogeneration apparatus. An electric power load, a heat storage device that stores the amount of heat output by the cogeneration device, a heat load that consumes the amount of heat output by the cogeneration device or the heat stored in the heat storage device, and each of the power generation plan formulation periods Of the power generation amount of the cogeneration device scheduled in the time zone and the electricity and heat output by the cogeneration device for the power generation amount of each time zone, the power load and the heat load can be used. The effective energy consumption, which is the amount of power and heat, is converted into the effective energy consumption for commercial power. Or the energy saving amount that is the value that is deducted from the primary energy consumption required when covered by a normal water heater, or the energy saving degree that is the value obtained by dividing the energy saving amount by the primary energy, or a similar energy saving index ( (Hereinafter referred to as “energy-saving amount etc.”) in a cogeneration system comprising: a power generation plan storage means for storing the power generation plan storage means for storing output within the power generation plan formulation period. If the sum of the energy saving amount, etc. in the continuous time zone section is smaller than the sum of the energy saving amount when the cogeneration device is stopped in the same time zone section, the Deciding to stop the cogeneration device in consecutive time periods .
[0022]
The second configuration of the output control method of the cogeneration system according to the present invention is, in the first configuration, among the time zone sections in the power generation plan formulation period, such as the energy saving amount in the time zone section. The lowest energy saving interval that is the time zone interval in which the total sum is minimum, and the sum of the energy saving amount and the like in the lowest energy saving interval are selected, and the sum of the energy saving amount and the like in the lowest energy saving interval and the cogeneration device are The sum of the energy saving amount and the like when stopped at is compared, and when the former is smaller than the latter, it is determined that the cogeneration apparatus is stopped in the lowest energy saving section.
[0023]
The output control program of the cogeneration system according to the present invention includes a cogeneration apparatus that outputs electricity by power generation and outputs exhaust heat accompanying power generation, a power load that consumes power output by the cogeneration apparatus, and A heat storage device that stores the exhaust heat output from the cogeneration device, a heat load that consumes the exhaust heat output from the cogeneration device or the exhaust heat stored in the heat storage device, and a computer that controls the cogeneration device A cogeneration system comprising: the computer is operated as an output control device according to claim 1 by being read and executed by the computer.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a configuration diagram of a cogeneration system according to Embodiment 1 of the present invention. The cogeneration system 1 according to the present embodiment includes, as main components, a fuel cell (hereinafter referred to as “FC”) 2, an inverter 3, an exhaust heat exchanger 4, a surplus power heater 5, an FC controller 6, It has a heating heat exchanger 7, a stratified hot water tank 8, an auxiliary heat source 9, and a hot water controller 10. In addition, in this embodiment, it has a heating load and a hot water supply load as a heat load.
[0025]
FC2 is supplied with natural gas and air as fuel. The FC 2 creates hydrogen from the supplied natural gas, generates power from the hydrogen and air, and outputs heat generated during power generation (hereinafter referred to as “exhaust heat”). The inverter 3 receives electricity output from the FC 2 and electricity transmitted from a commercial power source. And the inverter 3 supplies the electric power output from FC2 to electric power loads, such as an electric equipment in a facility, according to the electric power requested | required by an electric power load. In addition, when the electric power output from FC2 is insufficient with respect to the electric power requested | required by electric power load, the inverter 3 covers the shortage with the electric power supplied from a commercial power source.
[0026]
The exhaust heat generated during power generation in FC2 is taken out by the cooling water of FC2. The exhaust heat extracted by the cooling water is heat-exchanged with the circulating water supplied from the stratified hot water tank 8 as a heat storage device in the exhaust heat exchanger 4. This circulating water is taken out from the lower part of the stratified hot water tank 8 by the circulation pump 11 and sent to the exhaust heat exchanger 4. The circulating water supplied with the exhaust heat in the exhaust heat exchanger 4 is returned to the upper part of the stratified hot water tank 8 through the surplus power heater 5 and the heating heat exchanger 7.
[0027]
The FC controller 6 detects the current supplied to the power load by the current sensor 12 and the current supplied from the commercial power source by the current sensor 13. Thereby, the FC controller 6 can detect the power consumed in the power load and the power supplied from the commercial power source.
[0028]
When the power output from the FC 2 is larger than the power required from the power load, a reverse power flow from the FC 2 to the commercial power source occurs. In order to prevent such reverse power flow, the FC controller 6 converts part of the power output from the inverter 3 into electrothermal conversion when the current value detected by the current sensor 13 exceeds a predetermined threshold value. It turns to the surplus electric power heater 5 which is an apparatus. Then, surplus power is consumed in the surplus power heater 5 to prevent reverse power flow from the FC 2 to the commercial power source. The surplus power heater 5 converts the supplied power into heat, and supplies the heat generated by the electrothermal conversion to the circulating water. Thereby, surplus electric power is collect | recovered as heat with circulating water.
[0029]
The heating heat exchanger 7 exchanges heat supplied to the circulating water with a heat medium circulated to a heating load (not shown) such as a heating device. The heat medium of the heating load is sent from the heating load to the heating heat exchanger 7 by the heat medium circulation pump 14 and then returned to the heating load again through the auxiliary heat source 9.
[0030]
The stratified hot water tank 8 stores hot water having a temperature gradient from high to low from the top to the bottom. When hot water is supplied to a hot water supply load such as a kitchen or a bath, the hot water in the upper layer of the stratified hot water tank 8 is fed through the auxiliary heat source 9. And the decrease in the water in the stratified hot water tank 8 due to hot water supply is compensated by the water supply from the bottom of the stratified hot water tank 8. This water supply amount is detected by the flow sensor 15. Further, the temperature of the water at the time of water supply is detected by the temperature sensor 16.
[0031]
The stratified hot water tank 8 is provided with a plurality of temperature sensors 17a to 17e in the vertical direction. The temperature of each layer of hot water stored in the stratified hot water tank 8 can be detected by the temperature sensors 17a to 17e.
[0032]
Moreover, temperature sensors 18 and 19 for detecting the temperature of the heat medium are provided in the return pipe and the forward pipe from the heating load. Furthermore, a temperature sensor 20 for detecting a hot water supply temperature is provided in the hot water supply pipe to the hot water supply load.
[0033]
The controller 10 for hot water supply includes the temperature detected by the temperature sensors 16, 17 a to 17 e, 18, 19, 20, the amount of water supplied by the flow sensor 15, the amount of heat generated by the auxiliary heat source 9, and the heat of the heat medium circulation pump 14. The amount of heat actually consumed in the heating load or hot water supply load or the heat radiation loss in the stratified hot water tank 8 is detected from the medium circulation flow rate or the like. Further, the FC controller 6 and the hot water controller 10 cooperate to control the cogeneration system 1.
[0034]
FIG. 2 is a block diagram showing the configuration of the output control device of the cogeneration system according to the first embodiment of the present invention. In FIG. 2, FC2, inverter 3, surplus power heater 5, auxiliary heat source 9, circulation pump 11, and heat medium circulation pump 14 are the same as those in FIG.
[0035]
The output control device 30 according to this embodiment includes a load consumption prediction unit 31, a load storage unit 32, a power generation plan formulation unit 33, a power generation plan storage unit 34, a stop section determination unit 35, a minus energy saving amount storage unit 38, and a system. Control means 39 is provided. Further, the stop section determination means 35 includes a minimum energy saving section selection means 36 and a stop determination means 37, and the system control means 39 includes an FC operation control means 40.
[0036]
The output control device 30 according to the present embodiment is realized by the cooperation of the FC controller 6 and the water heater controller 10. Further, the load consumption amount prediction unit 31 includes a power consumption amount of the power load detected by the power consumption detection unit 41, a heat consumption amount of the heating load detected by the heating load heat amount detection unit 42, and a hot water supply load heat amount detection unit 43. Based on the detected amount of heat consumed by the hot water supply load, each time zone n (nε {0, 1,..., 23}), where time zone n is a time zone from n o'clock to n + 1 o'clock. The predicted value W of the power consumption or heat consumption of the power load, heating load, and hot water supply load.p(N), Qh(N), Qs(N) is determined and stored in the load storage means 32. Here, the power consumption detection means 41 is realized by the current sensors 12 and 13. The heating load heat amount detection means 42 is realized by the temperature sensors 18 and 19 and the hot water supply controller 10. The hot water supply load heat amount detecting means 43 is realized by the temperature sensors 16 and 20 and the flow rate sensor 15.
[0037]
The power generation plan formulation means 33 is the predicted value W of the power consumption or heat consumption of the power load, heating load, and hot water supply load in each time zone n stored in the load storage means 32.p(N), Qh(N), QsBased on (n), energy saving amount E within the power generation plan formulation periodsavThe power generation amount W of FC2 in each time slot n so that the sum of (n) is maximizedp(N) is determined and stored in the power generation plan storage means 34. In the present invention, the power generation amount W of FC2 in the time zone n by the power generation plan formulation means 33.pThe method for determining (n) is not particularly limited. Energy saving EsavThe method of calculating (n) will be described in detail later.
[0038]
The stop section determination unit 35 saves energy E in each time zone n (= 0,..., 23) within the power generation plan formulation period stored in the power generation plan storage unit 34.savReferring to (n), continuous time zone intervals [nstart, Nstop] (Nstart<Nstop, Nstart∈ {0, ..., 23}, nstop∈ {0,..., 23}), the total amount of energy savings in the time zone is defined as FC2 in the same time zone [nstart, Nstop], The power generation of the FC2 is determined to be stopped in this continuous time zone.
[0039]
The system control means 39 controls the operation of the FC 2 of the cogeneration system 1, the inverter 3, the surplus power heater 5, the auxiliary heat source 9, the circulation pump 11, the heat medium circulation pump 14, and the like. The system control means 39 has FC operation control means 40. The FC operation control means 40 generates the power generation output {W within the power generation plan formulation period stored in the operation plan storage means 34.p(N); n = 0,..., 23} and the control of the power generation output of the FC2 and the power generation stop and start control according to the operation stop time zone determined by the stop section determination means 35.
[0040]
The operation of the output control device of the cogeneration system according to this embodiment configured as described above will be described below. Here, first, an energy saving amount calculation model as a basis for calculating effective energy consumption and energy saving amount will be described. Then, details of the operation of the output control device will be described.
[0041]
[1] Energy saving calculation model
(1) Calculation model of effective energy consumption of cogeneration system
FIG. 3 shows a calculation model of the energy saving amount of the cogeneration system used in this embodiment. Here, first, FC power generation {Wfc(N); n∈ {0, 1,..., 23}}, load power consumption {Wp(N); n∈ {0, 1,..., 23}}, heating load heat quantity {Qh(N); n∈ {0, 1,..., 23}} and hot water supply load heat quantity {Qs(N); n∈ {0, 1,..., 23}} is a known value. Here, “FC power generation amount” refers to the amount of power generated by FC2. “Load power consumption” refers to a predicted value of power consumed by a power load. The “heating load heat amount” refers to a predicted value of the heat amount consumed by the heating load. The “hot water load heat amount” refers to a predicted value of the heat amount consumed by the hot water load.
[0042]
The power generation efficiency of FC2 is εefcThen, FC consumption gas quantity Q in time zone nfc(N) is represented by (Equation 1). Here, the “FC consumption gas amount” refers to a value obtained by converting the total amount of gas consumed by the FC 2 for power generation by the amount of heat.
[Expression 1]
[0043]
(1.1) Power consumption
FC power generation W in time zone nfcOf (n), the power that can actually be used in the power load is the FC power generation amount Wfc(N) to auxiliary machine power consumption WLElectricity amount W minusfc(N) -WLIt is. Here, “auxiliary power consumption” refers to the amount of power consumed in equipment (for example, auxiliary equipment such as an exhaust heat recovery pump) that must be operated in order for the FC 2 to generate power. It is also necessary to prevent the power generated by FC2 from flowing backward to the commercial power source. Therefore, it is necessary to consider separately the following two cases.
[0044]
(A) Wfc(N) -WL≦ WpIn the case of (n)
In this case, Wfc(N) -WLIs the load power consumption WpSince it is lower than (n), all the electric power generated by FC2 is consumed in the electric power load, and no reverse power flow to the commercial power source occurs. Therefore, effective load power consumption Weff(N) is expressed by (Expression 2). Here, “effective load power consumption” refers to the power consumed in the power load among the power output by the FC 2. In this case, insufficient power Wp(N) -Weff(N) is supplemented by electric power supplied from a commercial power source.
[Expression 2]
[0045]
(B) Wfc(N) -WL> WpIn the case of (n)
In this case, Wfc(N) -WLIs load power consumption WpSince (n) is exceeded, not all of the electric power generated by FC2 is consumed in the electric power load. Therefore, surplus power is consumed in the surplus power heater 5 in order to prevent reverse power flow to the commercial power source side. Therefore, the effective load power consumption W in this caseeff(N) is expressed by (Equation 3).
[Equation 3]
[0046]
Where Wsup(N) represents the power consumed in the surplus power heater 5 in the time zone n, and can be calculated by (Equation 4).
[Expression 4]
This heater power consumption Wsup(N) is recovered as heat by circulating water. The heat generation efficiency of the surplus power heater 5 is ηsupThen, the amount of heat Q recovered by the surplus power heater 5sup(N) is represented by (Equation 5).
[Equation 5]
[0047]
(1.2) Heat consumption
FC consumption gas quantity Q by (Equation 1)fcWhen (n) is determined, FC exhaust heat quantity QeThe value of (n) is determined by (Equation 6). Here, “FC exhaust heat amount” refers to the amount of heat that FC2 supplies to the circulating water as exhaust heat. In (Expression 6), hfcRepresents the thermal efficiency of the FC 2 and the exhaust heat exchanger 4 (hereinafter referred to as “FC thermal efficiency”).
[Formula 6]
[0048]
At this time, the heat output of the entire cogeneration system 1 (hereinafter referred to as “system heat output”) Q.sys(N) is represented by (Equation 7). As mentioned above, Wfc(N) -WL≦ WpIn the case of (n), Qsup(N) = 0.
[Expression 7]
[0049]
(A) The amount of heat consumed by the heating load
Heating load heat quantity Q in time zone nhIf the value of (n) is not 0, the system thermal output Qsys(N) is preferentially used for the heating load. However, in practice, the temperature of the circulating water supplied to the heating heat exchanger 7 is generally not so high as compared with the temperature required in the heating load. Therefore, heating load heat quantity QhSystem heat output Q for all (n)sysIt is difficult to cover with (n), and usually the heating load heat quantity QhPart of (n) is system thermal output QsysProvided by (n). The amount of heat Q supplied by the auxiliary heat source 9hsubThe remaining amount of heat is covered by (n).
[0050]
So, on average, the heating load heat quantity QhSystem thermal output Q in (n)sysThe rate at which (n) is used (hereinafter referred to as “heating load exhaust heat utilization rate”) is RhAnd At this time, system thermal output QsysOf (n), the amount of heat used for the heating load (hereinafter referred to as “heating consumption heat output”) Qheff(N) is represented by (Equation 8). Usually, RhThe value of is about 0.1.
[Equation 8]
[0051]
(B) Heat consumed by hot water supply load
The remaining amount of heat not used in the heating load in time zone n (hereinafter referred to as “heat storage supply heat amount”) Qt(N) = Qsys(N) -Qheff(N) is used in a hot water supply load. However, hot water supply load heat quantity Q in time zone nsSince (n) is determined, the hot water supply heat quantity QtNot all (n) are used for hot water supply loads. Accordingly, the remaining amount of heat not used for the hot water supply load in the time zone n is once stored in the stratified hot water storage tank 8 and then used for the hot water supply load in the later time zone.
[0052]
However, when heat is stored in the stratified hot water tank 8, a part of the heat stored over time is lost due to heat dissipation. Therefore, hot water supply heat quantity QtOf (n), the total amount of heat lost due to the heat radiation of the stratified hot water tank 8 in the later time zone is the heat radiation loss Ql(N). And the amount of heat actually used by the hot water supply load is converted into the effective hot water storage amount Q.seffIf (n), the effective hot water storage quantity Qseff(N) can be calculated by (Equation 9).
[Equation 9]
[0053]
Where heat dissipation loss QlHow to estimate (n) is a problem, but in this embodiment, as an example, the estimation is performed using the following simple model. First, the hot water supply heat quantity Q supplied to the stratified hot water tank 8 in the time zone n.tIn (n), the amount of heat remaining in the stratified hot water tank 8 in the time zone n + i that has passed i time zones from the time zone n is Qr(N; i). Then, the final heat dissipation loss Ql(N) can be expressed by (Equation 10). In (Equation 10), the sum of the right-hand side is Q while I takes a value from 0 to 23.rIt means that the sum is taken when (n; i) is not 0. R represents a heat dissipation coefficient.
[Expression 10]
[0054]
The amount of heat Q remaining in the hot water tank in time zone nr(N; 0) is represented by (Equation 11).
## EQU11 ##
[0055]
In addition, the amount of heat Q remaining in the hot water tank in the time zone n + i (i> 0)r(N; i) is estimated by (Equation 12) in order to simplify the calculation.
[Expression 12]
[0056]
(2) Energy saving calculation model
In the cogeneration system 1 as described above, the total energy consumed in the time zone n is the FC consumption gas amount Q.fcEqual to (n). The energy E that is effectively consumed out of all the energy supplied in the time zone n in the cogeneration system 1.eff(N) (hereinafter referred to as “effective energy consumption”) is the effective load power consumption Weff(N) Heating consumption heat output Qheff(N) and effective hot water storage calorie Qseff(N). Therefore, the energy use efficiency η of the cogeneration system 1sys(N) is represented by (Equation 13).
[Formula 13]
[0057]
On the other hand, the “energy saving amount” means the energy consumption when the effective power consumption in the time zone n in the cogeneration system is covered by the commercial power source and the conventional gas water heater, and the time zone n in the cogeneration system. The difference with the effective energy consumption.
[0058]
The power generation efficiency of the power plant is εp (0)[HHV], h energy efficiency of conventional general heating equipmenth (0)[HHV], h energy efficiency of conventional general water heaterss (0)[HHV]. At this time, the effective load power consumption WeffWhen (n) is covered by power supply from the power plant, the converted value W of primary energy consumed at the power planteff (0)(N) is expressed by (Expression 14).
[Expression 14]
[0059]
Similarly, heating consumption heat output Qheff(N), Effective hot water storage quantity QseffWhen (n) is covered by the heat output from the conventional general heating equipment, the converted value Q of the primary energy consumed in the conventional general heating equipment and water heaterheff (0)(N), Qseff (0)(N) is expressed by (Equation 15) and (Equation 16).
[Expression 15]
[Expression 16]
[0060]
Therefore, the energy consumption E when the effective energy consumption in the time zone n in the cogeneration system 1 is covered by the power supply from the power plant and the conventional gas water heater, etc.eff (0)(N) is expressed by (Equation 17).
[Expression 17]
Therefore, energy saving amount Esav(N) can be calculated by (Equation 18). In addition, energy saving degree ηsav(N) is defined by (Equation 19).
[Formula 18]
[Equation 19]
[0061]
In addition, although the case where there was a heating load was described here, in the case of a cogeneration system that does not have a heating load, QhBy setting (n) = 0, this model can be applied as it is.
[0062]
[2] Details of operation of output control device
FIG. 4 is a flowchart showing the output control method of the cogeneration system according to the first embodiment of the present invention.
[0063]
First, the power generation plan formulation means 33 calculates the FC power generation amount {W within the power generation plan formulation period.fc(N); n = 0,..., 23} are determined, and the energy saving amount {E for the determined FC power generation amountsav(N); n = 0,..., 23} is calculated. And these FC power generation amount {Wfc(N)} and energy saving {Esav(N)} is stored in the power generation plan storage means 34 (S1).
[0064]
Next, the minimum energy saving section selection means 36 is a time zone section (minimum energy saving section) [n of energy saving amount among the time zone sections within the power generation plan formulation period [nstart, Nstop]. And this minimum energy saving section [nstart, Nstop] Of total energy saving amount (hereinafter referred to as “minimum section energy saving amount”) EsavminIs calculated (S2). The details of the processing in step S2 (hereinafter referred to as “minimum energy saving section selection processing”) will be described in detail later.
[0065]
Next, the stop determination means 37 is the minimum section energy saving amount E.savminValue and minus energy saving Esavdss(S3) and Esavmin≦ EsavdssIn the case of the minimum energy saving interval [nstart, Nstop], The power generation stop of FC2 is determined (S4). Here, the “minus energy saving amount” refers to energy consumed by the FC2 before or after the start of power generation when the FC2 is started and stopped.
[0066]
And FC operation control means 40 is the lowest energy saving section [nstart, Nstop], The FC power generation amount {W stored in the power generation plan storage means 34fc(N)} and continuously operating while controlling the power generation amount of FC2, the lowest energy saving interval [nstart, Nstop], Operation control of FC2 is performed so as to stop FC2 (S5).
[0067]
On the other hand, in step S3, Esavmin> EsavdssIn the case of the minimum energy saving interval [nstart, Nstop], It is determined to continuously operate the FC2 within the power generation plan formulation period without stopping the power generation of the FC2. The FC operation control means 40 then calculates the FC power generation amount {W stored in the power generation plan storage means 34.fc(N)} Continuous operation is performed while controlling the power generation amount of FC2.
[0068]
Here, the “minus energy saving amount” refers to the total energy loss that occurs when the FC2 is started and stopped. Negative energy savings include the amount of gas and power consumed for preheating the reformer at FC2 startup, the power consumption of the reformer cooling pump and cooling fan before and after FC2 power generation is started, etc. Is included.
[0069]
The above is the overall flow of the output control method according to the present embodiment. Next, the minimum energy saving section selection process will be described in detail.
[0070]
FIG. 5 is a flowchart showing the minimum energy saving section selection process.
In the minimum energy saving section selection process, first, the stop section determining means 35 performs the energy saving amount section minimum value E.savminIs initialized to 0 (S1). Next, the value of the parameter s representing the beginning of the time zone interval is set to 0 (S12), and the value of the parameter s representing the end of the time zone interval is set to 0 (S13).
[0071]
Next, it is determined whether or not s ≠ e (S14). Here, in the case of s ≠ e, first, the sum E of energy saving amounts in the time zone [s, e].savIs initialized to 0 (S15), and it is determined whether or not s <e (S16).
[0072]
Here, in the case of s <e, the energy saving amount E in the time zone s to esav(S) -EsavThe value of (e) is the sum of energy savings EsavTo obtain the total energy saving amount of the time zone [s, e] (S17 to S19).
[0073]
On the other hand, in step S16, when s ≧ e, the energy saving amount E in time zones 0 to e and time zones s to 23 is set.sav(0) to Esav(E), Esav(S) -EsavThe value of (23) is the sum of energy savings EsavTo obtain the total energy saving amount of the time zone [0, e], [s, 23] (S20 to S25). That is, in this case, the sum of energy saving amounts in the time zone [s, e] = {s, s + 1,..., 23, 0,.
[0074]
Next, the sum E for the time zone interval [s, e]savIs the minimum section E of the current energy saving amountsavminIt is determined whether it is smaller than (S26). Where Esavmin<EsavIn the case of, energy saving amount section minimum value EsavminThe value of Esav(S27), time zone n at the front end of the minimum sectionstartThe value of s, the time zone n at the end of the minimum intervalstopIs replaced with e (S28, S29).
[0075]
When s = e in step S14, the front end and the rear end of the section are in the same time zone, so the operations from S15 to S29 are not performed.
[0076]
The operations from steps S14 to S29 are repeated while changing the values of time zones s and e from 0 to 23 (S30, 31), and the process is terminated.
[0077]
By this minimum energy saving interval selection process, the time zone interval [nsta rt, Nstop] And energy saving amount section minimum value EsavminThe value of is obtained.
[0078]
FIG. 6 is a diagram showing an example of the time change of the energy saving amount per day. In the example of FIG. 6, the total amount of energy saving is the minimum in the time zone from 22:00 to 5:00 on the next day. Therefore, the total amount E of energy savings in the time zone [22, 5]savminValue and minus energy saving EsavdssTo the value of Esavmin≦ EsavdssIn this case, the operation of FC2 is stopped.
[0079]
As described above, according to the present embodiment, the time period [n in which the energy saving amount is minimizedstart, Nstop] The minimum section E of energy saving amountsavminThe value of minus energy saving amount EsavdssIf the former is smaller than the time zone [nstart, Nstop], It is possible to further improve the energy saving performance as compared with the case of continuous operation.
[0080]
In this embodiment, the energy saving amount is used as a reference value for determining whether or not to stop the operation of the FC 2. However, in the present invention, the energy saving degree can be used instead of the energy saving amount.
[0081]
In this embodiment, the FC controller 6 and the hot water controller 10 are configured by microcomputers, and the microcomputer executes the output control program of the cogeneration system, thereby realizing the output control device. Also good.
[0082]
【The invention's effect】
As described above, according to the present invention, when it is more advantageous from the viewpoint of energy saving or degree of energy saving than to continuously operate the cogeneration device in a continuous time zone section within the power generation plan formulation period. The stop section determining means determines to stop the cogeneration apparatus. Therefore, it is possible to maximize the energy saving performance of the entire cogeneration system including the energy loss at the time of starting or stopping the cogeneration apparatus.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a cogeneration system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the output control device of the cogeneration system according to the first embodiment of the present invention.
FIG. 3 is a diagram showing a calculation model of energy saving amount of the cogeneration system used in the present embodiment.
FIG. 4 is a flowchart showing an output control method of the cogeneration system according to the first embodiment of the present invention.
FIG. 5 is a flowchart showing a minimum energy saving section selection process.
FIG. 6 is a diagram illustrating an example of a temporal change in the amount of energy saved per day.
[Explanation of symbols]
1 Cogeneration system
2 Fuel cell (FC)
3 Inverter
4 Waste heat exchanger
5 Surplus power heater
6 FC controller
7 Heating heat exchanger
8 Stratified hot water tank
9 Auxiliary heat source
10 Hot water controller
11 Circulation pump
12,13 Current sensor
14 Heating medium circulation pump
15 Flow sensor
16, 17a-17e, 18, 19, 20 Temperature sensor
30 Output control device
31 Load consumption prediction means
32 Load storage means
33 Power generation plan formulation means
34 Power generation plan storage means
35 Stop section determination means
36 Minimum energy saving section selection means
37 Stop determination means
38 Minus energy saving means
39 System control means
40 FC operation control means
41 Power consumption detection means
42 Heating load calorie detection means
43 Hot water supply load calorie detection means

Claims (5)

  1. A cogeneration device that outputs power by power generation and outputs the amount of heat generated by power generation;
    A power load that consumes the power output by the cogeneration device;
    A heat storage device that stores the amount of heat output by the cogeneration device, and
    A heat load that consumes the amount of heat output by the cogeneration device or the amount of heat stored in the heat storage device; and
    A cogeneration system comprising: an output control device that performs output control of the cogeneration device,
    Of the power generation amount of the cogeneration device scheduled in each time zone within the power generation plan formulation period, and the electricity load and the heat output from the cogeneration device with respect to the power generation amount in each time zone, the power load and An energy saving amount that is a value obtained by subtracting from the primary consumption energy required when the effective consumption energy is provided by a commercial power source or a normal water heater, for the amount of power and the amount of heat that can be used by the heat load, or A power generation plan storage means for storing an energy saving degree which is a value obtained by dividing the energy saving amount by the primary energy, or an energy saving index similar thereto (hereinafter referred to as "energy saving amount");
    Among the continuous time zone sections in the power generation plan formulation period, the sum of the energy saving amount in the time zone section is more than the sum of the energy saving amount when the cogeneration device is stopped in the same time zone section. If it is smaller, the output control device further comprises stop section determining means for determining that the cogeneration apparatus is stopped in the continuous time zone section.
  2. The stop section determining means is
    Among the time zone sections in the power generation plan formulation period, select the lowest energy saving section that is the time zone section in which the total sum of the energy saving amounts, etc. in the time zone section is the minimum, and the energy saving amount in the lowest energy saving section A minimum energy saving section selection means for calculating the sum of
    The total energy saving amount in the minimum energy saving section is compared with the total energy saving amount in the case where the cogeneration apparatus is stopped in the minimum energy saving section. When the former is smaller than the latter, the minimum energy saving Stop determination means for determining to stop the cogeneration device in a section;
    The output control apparatus according to claim 1, further comprising:
  3. A cogeneration device that outputs power by power generation and outputs the amount of heat generated by power generation;
    A power load that consumes the power output by the cogeneration device;
    A heat storage device that stores the amount of heat output by the cogeneration device, and
    A heat load that consumes the amount of heat output by the cogeneration device or the amount of heat stored in the heat storage device; and
    Of the power generation amount of the cogeneration device scheduled in each time zone within the power generation plan formulation period, and the electricity load and the heat output from the cogeneration device with respect to the power generation amount in each time zone, the power load and An energy saving amount that is a value obtained by subtracting from the primary consumption energy required when the effective consumption energy is provided by a commercial power source or a normal water heater, for the amount of power and the amount of heat that can be used by the heat load, or A power generation plan storage means for storing an energy saving degree which is a value obtained by dividing the energy saving amount by the primary energy, or an energy saving index similar thereto (hereinafter referred to as "energy saving amount");
    In the cogeneration system comprising: an output control method for controlling the output of the cogeneration apparatus,
    Among the continuous time zone sections in the power generation plan formulation period, the sum of the energy saving amount in the time zone section is more than the sum of the energy saving amount when the cogeneration device is stopped in the same time zone section. If it is smaller, it is determined to stop the cogeneration apparatus in the continuous time zone section.
  4. Among the time zone sections in the power generation plan formulation period, select the lowest energy saving section that is the time zone section in which the total sum of the energy saving amounts, etc. in the time zone section is the minimum, and the energy saving amount in the lowest energy saving section And so on,
    The total energy saving amount in the minimum energy saving section is compared with the total energy saving amount in the case where the cogeneration apparatus is stopped in the minimum energy saving section. When the former is smaller than the latter, the minimum energy saving The output control method according to claim 3, wherein the cogeneration apparatus is determined to be stopped in a section.
  5. A cogeneration device that outputs electricity by power generation and outputs waste heat from power generation;
    A power load that consumes the power output by the cogeneration device;
    A heat storage device for storing exhaust heat output from the cogeneration device;
    A heat load that consumes exhaust heat output by the cogeneration device or exhaust heat stored in the heat storage device; and
    A computer for controlling the cogeneration apparatus;
    In the cogeneration system with
    An output control program for a cogeneration system, wherein the computer is operated as the output control device according to claim 1 by being read and executed by the computer.
JP2003174975A 2003-06-19 2003-06-19 Output control device and output control method for cogeneration system Pending JP2005009781A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006250471A (en) * 2005-03-11 2006-09-21 Osaka Gas Co Ltd Energy supply system
JP2006269275A (en) * 2005-03-24 2006-10-05 Osaka Gas Co Ltd Fuel cell system
JP2006275479A (en) * 2005-03-30 2006-10-12 Osaka Gas Co Ltd Energy supply system
JP2007247968A (en) * 2006-03-15 2007-09-27 Osaka Gas Co Ltd Cogeneration system
JP2008190755A (en) * 2007-02-02 2008-08-21 Osaka Gas Co Ltd Cogeneration system
JP2011149433A (en) * 2011-02-25 2011-08-04 Tokyo Gas Co Ltd Cogeneration system and operation control method for the same
JP2017048996A (en) * 2015-09-04 2017-03-09 大阪瓦斯株式会社 Cogeneration system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006250471A (en) * 2005-03-11 2006-09-21 Osaka Gas Co Ltd Energy supply system
JP4516862B2 (en) * 2005-03-11 2010-08-04 大阪瓦斯株式会社 Energy supply system
JP2006269275A (en) * 2005-03-24 2006-10-05 Osaka Gas Co Ltd Fuel cell system
JP2006275479A (en) * 2005-03-30 2006-10-12 Osaka Gas Co Ltd Energy supply system
JP4516875B2 (en) * 2005-03-30 2010-08-04 大阪瓦斯株式会社 Energy supply system
JP2007247968A (en) * 2006-03-15 2007-09-27 Osaka Gas Co Ltd Cogeneration system
JP2008190755A (en) * 2007-02-02 2008-08-21 Osaka Gas Co Ltd Cogeneration system
JP2011149433A (en) * 2011-02-25 2011-08-04 Tokyo Gas Co Ltd Cogeneration system and operation control method for the same
JP2017048996A (en) * 2015-09-04 2017-03-09 大阪瓦斯株式会社 Cogeneration system

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