Server, building energy management system and building energy management method

Abstract

The server (10) is provided with a processor (11) that executes a calculation process for determining which of the plurality of energy storage devices (30) the generated power of the naturally varying power source (20) is stored in. The processor (11) extracts, from among the plurality of energy storage devices (30), one or more energy storage devices for which the remaining power exceeds a predetermined amount, in a case where the power generated by the naturally varying power source (20) exceeds the power consumed by the building and the remaining power is generated, the time period is longer than the time period for which the energy is required to be continuously stored in accordance with the specification of the device. The processor (11) calculates, for each of the one or more energy storage devices, a reduction amount of electric charge when remaining power is stored in the energy storage device, and determines the energy storage device in which the remaining power is stored on the basis of the reduction amount.

Description

Technical Field

[0001] The present disclosure relates to a server, a building energy management system having the server, and a building energy management method. Background Art

[0002] In recent years, as the importance of renewable energy has been widely recognized, the number of buildings equipped with solar power generation (PV: photovoltaics) equipment has increased. As PV equipment has become more popular, the power generation capacity of PV equipment has also increased. There are also buildings where the primary energy balance in a year reaches zero (or approximately zero) due to the increase in power generation capacity of PV equipment, namely "ZEB (net Zero Energy Building: zero energy building)".

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-295680

[0006] Patent Document 2: Japanese Patent Application Publication No. 2017-79564

[0007] Patent Document 3: Japanese Patent Application Publication No. 2019-88151

[0008] Patent Document 4: International Publication No. 2013 / 168814 Summary of the invention

[0009] Problems to be solved by the invention

[0010] For example, as disclosed in Japanese Patent Application Laid-Open No. 2007-295680 (Patent Document 1), it is being studied to install energy storage equipment that stores energy in the form of electricity or heat in buildings in addition to PV equipment. These energy storage equipments store energy during time periods when power demand is low and electricity rates are low (such as nighttime), and consume energy during time periods when power demand is high and electricity rates are high (such as daytime), thereby achieving energy conservation and reducing electricity rates.

[0011] In buildings such as ZEB, the amount of electricity generated by PV equipment sometimes exceeds the amount of electricity consumed by the building, resulting in surplus power. This surplus power may change over time due to weather changes, etc. In addition, sometimes multiple energy storage devices (combinations of power storage devices and heat storage devices, etc.) are installed in a building. In such cases, how to effectively utilize the surplus power while balancing energy saving and economic efficiency may become a problem.

[0012] The present disclosure is made to solve the above-mentioned problems, and one of the purposes of the present disclosure is to take into account both energy saving and economy in a building.

[0013] Means for solving problems

[0014] A server in one embodiment of the present disclosure manages energy in a building, in which a naturally variable power source whose power generation varies according to meteorological conditions and a plurality of energy storage devices that store energy in the form of electricity or heat are provided. The server has a processor that performs a calculation process for determining in which of a plurality of energy storage devices the power generation of the naturally variable power source is to be stored. In a case where the power generation of the naturally variable power source exceeds the power consumption of the building and surplus power is generated, the processor extracts from the plurality of energy storage devices one or more energy storage devices in which the period during which the surplus power exceeds a prescribed amount is longer than the period during which the energy is required to be continuously stored according to the specifications of the device, calculates, for each of the one or more energy storage devices, the amount of reduction in the electricity bill when the surplus power is stored in the energy storage device, and determines the energy storage device that stores the surplus power based on the reduction amount.

[0015] Another aspect of the building energy management method disclosed herein manages energy in a building, in which a naturally variable power source whose power generation varies according to meteorological conditions and a plurality of energy storage devices that store energy in the form of electricity or heat are provided. The building energy management method includes steps 1 to 4. Step 1 is a step of determining whether the power generation of the naturally variable power source exceeds the power consumption of the building and generates surplus power. Step 2 is a step of extracting, when surplus power is generated, from a plurality of energy storage devices, one or more energy storage devices whose period of surplus power exceeds a prescribed amount is longer than the period during which energy is required to be continuously stored. Step 3 is a step of calculating, for each of the one or more energy storage devices, the amount of reduction in electricity charges when surplus power is stored in the energy storage device, and determining the energy storage device that stores the surplus power based on the amount of reduction.

[0016] Effects of the Invention

[0017] According to the present disclosure, energy saving and economy in a building can be achieved at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing an example of the overall configuration of the building energy management system according to the present embodiment.

[0019] Figure 2 is a diagram showing a typical structure of a server.

[0020] Figure 3 This is a diagram used to explain device specification data.

[0021] Figure 4 This is a schematic diagram used to explain equipment performance data.

[0022] Figure 5 It is a schematic diagram for explaining the first power consumption data.

[0023] Figure 6 It is a schematic diagram for explaining the second power consumption data.

[0024] Figure 7 This is a diagram for explaining an electricity meter.

[0025] Figure 8 This is a functional block diagram of the server in this embodiment.

[0026] Fig. 9 This is a diagram for explaining an example of a method for calculating surplus power.

[0027] Fig.10 This is a diagram for explaining an example of a method for extracting candidates for an energy storage device that stores surplus power.

[0028] Fig.11 This is a diagram for explaining an example of a cost calculation method.

[0029] Fig.12 1 is a flowchart showing a processing procedure of a calculation process related to surplus power in the embodiment.

[0030] Fig.13 It is a diagram for explaining a method of extracting candidates for an energy storage device that stores surplus power in a modified example.

[0031] Fig.14 1 is a flowchart showing a processing procedure of a calculation process related to surplus power in a modification example. DETAILED DESCRIPTION

[0032] Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in the drawings, and their description will not be repeated.

[0033] Implementation method.

[0034] <System Structure>

[0035] Figure 1 This is a diagram showing an example of the overall structure of a building energy management system (BEMS) according to the present embodiment. In the present embodiment, BEMS1 manages the supply and demand of energy (electricity and / or heat) used in an office building. However, facilities to which BEMS1 can be applied are not limited to office buildings, but may also be commercial facilities (shopping centers, etc.), sports facilities (stadiums, etc.), cultural facilities (theaters, etc.), etc., or may be complex facilities thereof.

[0036] The BEMS 1 includes a server 10. The server 10 is a computer that manages each device of the BEMS 1. Figure 2 The hardware configuration of the server 10 will be described. The server 10 is connected to a central server 5 and external servers 6 and 7 via a network 8 such as the Internet so as to be able to communicate with each other.

[0037] The central server 5 is installed in an information center operated by a company that manages a plurality of buildings in an integrated manner. The central server 5 provides the server 10 with various information required for managing each device of the BEMS 1. The central server 5 is configured to be able to remotely control each device in the BEMS 1.

[0038] The external server 6 is operated by the Meteorological Bureau, a private meteorological operator, etc., and provides weather forecasts and weather information (weather, external air temperature, sunshine, wind speed, wind direction, precipitation, precipitation probability, etc.) to the server 10. The external server 6 may also provide the server 10 with forecasts of meteorological disasters (warnings or alarms related to typhoons, heavy rain, floods, heavy snow, strong winds, heat waves, cold waves, lightning strikes, etc.).

[0039] The external server 7 is operated by, for example, an electric power company (which may be a power generation operator or a power transmission / distribution operator), and provides information on electricity charges to the server 10 .

[0040] The BEMS 1 includes one or more naturally variable power sources 20, a plurality of energy storage devices 30, a load 40, and an indoor management system 50 in addition to the server 10. The naturally variable power source 20, the energy storage device 30, and the load 40 are connected to the power system 9, for example.

[0041] One or more naturally variable power sources 20 are power generation equipment whose power generation may vary according to meteorological conditions. In the present embodiment, the naturally variable power source 20 is a solar power generation equipment (PV equipment). However, the naturally variable power source 20 may also be a wind power generation equipment, or a combination of a PV equipment and a wind power generation equipment.

[0042] The multiple energy storage devices 30 are devices that store energy in the form of electricity or heat. In this embodiment, the multiple energy storage devices 30 include an electrical storage device 31, a thermal storage device 32, and a hot water supply device 33. The multiple energy storage devices 30 may include only any one or two types of devices among these devices. The multiple energy storage devices 30 may also include a power-to-gas device (not shown) that uses electricity to produce gas fuel (hydrogen, methane, etc.).

[0043] The power storage device 31 is configured to store the power generated by the naturally variable power source 20. The power storage device 31 is typically a secondary battery (lithium ion battery, nickel metal hydride battery, etc.) or an electric double layer capacitor. The power that the power storage device 31 can store or supply varies depending on the charge and discharge power, charging time, and charging efficiency. The power stored (accumulated) in the power storage device 31 may decrease over time.

[0044] The thermal storage device 32 is configured to store heat generated in conjunction with air conditioning (cooling or heating) in the building. The thermal storage device 32 includes, for example, a thermal storage tank, and stores a liquid medium (typically hot water) in the thermal storage tank in an insulated state. The thermal storage device 32 may be a waste heat recovery system or an ice thermal storage system. The thermal storage device 32 supplies the heat stored in the form of hot water or ice to the load 40 (particularly the air conditioning equipment) of the building. The temperature of the hot water or ice stored in the thermal storage device 32 may change over time.

[0045] The hot water supply device 33 includes a heat exchanger for heating water. The hot water supply device 33 may be various types of hot water suppliers, such as an electric hot water supplier, a heat pump hot water supplier, and a solar hot water supplier. The hot water supply device 33 supplies hot water to the load 40 of the building. The temperature of the hot water stored in the hot water supply device 33 may also change over time.

[0046] In the electrical storage device 31, stored energy refers to the amount of stored electricity, which is represented by, for example, the charge rate (SOC: State Of Charge). In the thermal storage device 32 or the hot water supply device 33, stored energy refers to the amount of stored heat, which is represented by, for example, the temperature of the hot water or water.

[0047] The load 40 is a device that consumes energy (mainly electric power) and includes, for example, air conditioning equipment, lifts (elevators, escalators, etc.), lighting equipment, and various OA (Office Automation) equipment installed in a building.

[0048] The indoor management system 50 is configured to manage data related to the entry and exit of people in each room in the building using technologies such as IC (Integrated Circuit) cards, surveillance cameras, and biometric authentication.

[0049] Hereinafter, the calculation process executed by the server 10 in the BEMS 1 will be described. Although not shown, the central server 5 installed in the information center can also have the same structure as the server 10. Therefore, the central server 5 may execute the following calculation process instead of the server 10.

[0050] <Server Structure>

[0051] Figure 2is a diagram showing a typical structure of the server 10. The server 10 includes a processor 11, a memory 12, an input device 13, a display 14, a communication interface 15, and a database 16.

[0052] The processor 11 is, for example, a CPU (Central Processing Unit), and is configured to perform predetermined calculation processing according to a program. The memory 12 includes a ROM (Read Only Memory) 121, a RAM (Random Access Memory) 122, and a HDD (Hard Disk Drive) 123, and stores a program executed by the processor 11 and various data (mapping diagrams, relational expressions, parameters, etc.) used in the program. The input device 13 is a keyboard, a mouse, etc., and accepts user operations. The display 14 provides various information to the user. The communication interface 15 is configured to communicate with the outside (central server 5, external servers 6, 7, etc.).

[0053] In this example, the database 16 includes a device specification database 161 storing device specification data, a device performance database 162 storing device performance data, a weather database 163 storing first power consumption data, an indoor database 164 storing second power consumption data, and an electricity rate database 165 storing an electricity rate table. Figure 3 to Figure 7 , explain these data or tables.

[0054] <Database>

[0055] Figure 3 It is a schematic diagram for explaining the device specification data. The device specification data refers to the data that records the specifications of each device in order to manage the naturally varying power source 20 and the energy storage device 30 in the BEMS 1. In this example, each device of the naturally varying power source 20 and the energy storage device 30 is assigned an identification number (device ID) of the device. The device specification data includes the type of device, capacity (the maximum energy that can be stored in the device) and rated power (the maximum energy that can be input and output per unit time in the device) for each device ID. The device specification data may also include a manufacturer (not shown), a model (not shown), a location of installation, etc.

[0056] In the present embodiment, regarding the energy storage device 30, the device specification data also includes the required power and the required period. Generally speaking, the power storage device 31 is able to immediately store any amount of electricity within the range of the capacity and the rated power. In contrast, in the thermal storage device 32 and the hot water supply device 33, the conversion from electric energy to thermal energy is performed. More specifically, the generation (reheating) of hot water in the thermal storage tank, the generation of ice in the ice thermal storage system, the generation (reheating) of hot water for hot water supply, etc. are performed. In such energy conversion, it is necessary to continuously supply power exceeding the prescribed amount to the thermal storage device 32 or the hot water supply device 33 for a certain period of time. Therefore, the minimum power and period required for efficient energy conversion are respectively determined as the required power and the required period.

[0057] Figure 4 This is a schematic diagram for explaining the equipment performance data. Equipment performance data refers to data that records the equipment's usage performance (past monitoring results of the server 10). Regarding the naturally variable power source 20, the equipment performance data includes the time and the performance value of the generated power at that time as data associated with the equipment ID. Regarding the energy storage device 30, the equipment performance data includes the time, the performance value of the stored energy at that time, or the performance value of the supplied energy (the amount of stored energy supplied) at that time as data associated with the equipment ID. In addition, the time includes the power generation time, the energy storage time, and the energy supply time.

[0058] Figure 5 1 is a schematic diagram for explaining the first power consumption data. The first power consumption data refers to data that records the power consumption of BEMS 1 (the entire building) in association with weather information. In this example, the first power consumption data includes, for each time, weather information (external air temperature, sunshine, precipitation, various alarms issued, etc.) at that time and the actual value of the power consumption of the entire building generated by the load 40 in the building at that time. In addition, the server 10 obtains weather information from the external server 6.

[0059] Figure 6 2 is a schematic diagram for explaining the second power consumption data. The second power consumption data refers to data that records the power consumption of BEMS1 (the entire building) in association with indoor information. As described above, in BEMS1, the number of people in each room is obtained by the indoor management system 50. In this example, the second power consumption data includes the time, the number of people in each room at that time, and the actual value of the power consumption of the entire building generated by the load 40 in the building at that time.

[0060] Due to the heat generated by people, the more people there are in the room, the higher the room temperature. In addition, there is a trend that the more people there are in the room, the greater the power consumption of the lighting equipment or the greater the power consumption of the OA equipment. The second power consumption data may also be data obtained by finding the correlation between the number of people in the room and the power consumption of each device through multivariate analysis, machine learning, etc.

[0061] Figure 7 Schematic diagram for explaining an electricity rate table. The electricity rate table includes data on electricity rate unit prices (prices per kWh) for different ranges of generated power or consumed power, for example, for each time period. The server 10 acquires the electricity rate table from the external server 7 .

[0062] <Function box>

[0063] Figure 8 1 is a functional block diagram of the server 10 in the present embodiment. The server 10 includes a generated power estimation unit 101 , a power demand estimation unit 102 , a surplus power calculation unit 103 , a candidate extraction unit 104 , a cost calculation unit 105 , and a device determination unit 106 .

[0064] The power generation estimation unit 101 estimates the power generation based on the natural variable power source 20 (in this embodiment, a PV device). In the case where the natural variable power source 20 includes a plurality of devices (e.g., a PV device and a wind power generation device), the power generation estimation unit 101 estimates the power generation for each of the plurality of devices. The power generation is estimated for each predetermined time frame (e.g., 30 minutes) within a predetermined period in the future (which may be 24 hours, 3 days, or 1 week) from the current moment. The power generation estimation unit 101 can estimate the power generation for each time frame based on the weather forecast (weather, outside air temperature, sunshine, wind speed, wind direction, precipitation, precipitation probability, etc.) obtained from the external server 6 and the performance value (history) of the power generation included in the device performance data. The power generation estimation unit 101 outputs the estimation result of the power generation to the surplus power calculation unit 103.

[0065] The power demand estimation unit 102 estimates the power demand (also referred to as power consumption) in the BEMS 1 for each of the above-mentioned time frames during the above-mentioned prescribed period. More specifically, the power demand estimation unit 102 can estimate the power demand for each time frame based on the weather forecast obtained from the external server 6, the indoor management information obtained from the indoor management system 50, and the actual value of power consumption included in the first power consumption data and the second power consumption data.

[0066] The power demand estimation unit 102 may estimate the power demand based on only the first power consumption data. However, the power demand estimation unit 102 uses both the first power consumption data and the second power consumption data, in other words, uses the second power consumption data to correct the first power consumption data, thereby improving the estimation accuracy of the power demand. The power demand estimation unit 102 outputs the estimation result of the power demand to the surplus power calculation unit 103.

[0067] The surplus power calculation unit 103 calculates the surplus power in the BEMS 1 based on the generated power estimated by the generated power estimation unit 101 and the power demand estimated by the power demand estimation unit 102 .

[0068] Fig. 9 2 is a diagram for explaining an example of a method for calculating surplus power. The surplus power calculation unit 103 calculates the difference between the surplus power and the power demand as surplus power for each of the time frames within the predetermined period.

[0069] return Figure 8 The candidate extraction unit 104 extracts one or more devices that can store energy equivalent to the surplus power (ie, devices that can store surplus power or devices that can store heat generated by surplus power) from the plurality of energy storage devices 30 as candidates.

[0070] Fig.10 1 is a diagram for explaining an example of a method of extracting candidates of the energy storage device 30 that stores surplus power. The candidate extracting unit 104 extracts candidates based on two conditions.

[0071] The first condition refers to a condition related to the free capacity of the energy storage device 30 (the remaining energy that can be stored in the device). The free capacity of the energy storage device 30 can be calculated by the difference between the capacity of the device (the maximum energy that can be stored in the device) and the energy stored in the device. The candidate extraction unit 104 can obtain the capacity from the device specification data and obtain the stored energy from the device performance data. When the energy storage device 30 has a free capacity that can store energy equivalent to the remaining power, the candidate extraction unit 104 determines that the device satisfies the first condition.

[0072] exist Fig.10 In the example shown, the plurality of energy storage devices 30 include three devices A, B, and C. Here, it is assumed that the three devices A, B, and C all satisfy the first condition.

[0073] The second condition is Figure 4Conditions related to the required power and required period required for efficient energy conversion described in . The required power of device A is recorded as Pa, and the required period of device A is recorded as Ta. The same is true for devices B and C. In this example, the required period Ta during which the required surplus power exceeds the required power Pa is equivalent to 4 time frames (for example, 2 hours). The required periods Tb and Tc are equivalent to 3 time frames (for example, 1.5 hours). The surplus powers in the four time frames t1 to t4 are recorded as P1 to P4, respectively.

[0074] Regarding device A, in three time frames t1 to t3 among the four time frames t1 to t4 corresponding to the required period Ta, the surplus power P1 to P3 exceeds the required power Pa. However, the surplus power P4 in the time frame t4 does not satisfy the required power Pa. In this case, in the time frame t4, the energy required for the generation of hot water in the thermal storage tank and the generation of ice in the ice thermal storage system is not supplied to device A, and efficient energy conversion may not be achieved. Therefore, device A is not extracted as a candidate.

[0075] On the other hand, regarding device B, in any of the three time frames t1 to t3 corresponding to the required period Tb, the surplus power P1 to P3 exceeds the required power Pb. Similarly, regarding device C, in any of the three time frames t1 to t3, the surplus power P1 to P3 exceeds the required power Pc. In this case, since the energy required for the generation of hot water, the generation of ice, etc. is supplied to devices B and C, efficient energy conversion can be achieved. Therefore, devices B and C are extracted as candidates.

[0076] Refer again Figure 8 The cost calculation unit 105 calculates the cost that is reduced when surplus power (energy equivalent to the surplus power) is accumulated in each of the one or more candidates (devices B and C in this example) extracted by the candidate extraction unit 104.

[0077] Fig.11 : is a diagram for explaining an example of a method for calculating costs. First, the cost calculation unit 105 calculates the cost reduction amount for each device B and C. The cost reduction amount refers to the estimated amount of cost that is reduced when energy is stored in the energy storage device 30. For example, the cost calculation unit 105 uses the unit price included in the electricity rate table to convert the energy (electricity or the amount obtained by converting heat into electricity) stored in the device into an amount, thereby being able to calculate the cost reduction amount based on the device. In this example, the cost reduction amount of device B is 14,000 yen, and the cost reduction amount of device C is 15,000 yen.

[0078] The cost calculation unit 105 calculates the energy loss amount for each device B and C. The energy loss amount refers to the amount obtained by converting the energy loss generated until the energy stored in the energy storage device 30 is supplied to the load 40 into an amount. As described above, the device performance data includes the energy loss generated per unit time (per time frame) in each energy storage device 30. In addition, since the device performance data includes the energy supply time of each energy storage device 30, it is possible to predict the time when each energy storage device 30 will next supply energy to the load 40. Therefore, the cost calculation unit 105 calculates the total amount of energy loss until the energy supply time based on the energy loss per unit time, and uses the unit price included in the electricity rate table to convert the calculated total amount of energy loss into an amount, thereby being able to calculate the energy loss amount. In this example, the energy loss amount of device B is 1,000 yen, and the energy loss amount of device C is 3,000 yen.

[0079] The cost calculation unit 105 calculates the actual cost reduction amount by subtracting the energy loss amount from the cost reduction amount for each device B and C. In this example, the actual cost reduction amount of device B is 14,000 yen - 1,000 yen = 13,000 yen, and the actual cost reduction amount of device C is 15,000 yen - 3,000 yen = 12,000 yen. That is, when comparing device B and device C, the cost reduction amount of device C without considering the energy loss is larger, but the actual cost reduction amount of device B considering the energy loss is larger.

[0080] return Figure 8 The device determination unit 106 selects the candidate (in Fig.10 In the example described in the figure, the device B and C are used to determine the device that stores the surplus power. More specifically, the device determination unit 106 determines the device (in the device B and C) that has the largest actual cost reduction calculated by the cost calculation unit 105. Fig.11 In the example described in , the device B) is determined as the device for storing the surplus power. The device determination unit 106 outputs an energy storage instruction to the determined device.

[0081] <Processing Flow>

[0082] Fig.12 1 is a flowchart showing the processing procedure of the calculation processing related to the surplus power in the embodiment. The processing shown in the flowchart is executed when a predetermined condition is met (for example, at each specified cycle). Each step is implemented by software processing based on the processor 11 in the server 10, but can also be implemented by hardware (circuitry) configured in the server 10. Hereinafter, the step is referred to as S.

[0083] In S11, the server 10 estimates the power generated by the natural variable power source 20 of the entire building for each time frame within a predetermined period in the future. In this embodiment, the power generated by the PV device is estimated. The server 10 can estimate the power generated for each time frame within the predetermined period based on the weather information (e.g., the amount of sunshine) and the performance value of the power generated by each PV device included in the device performance data.

[0084] In S12, the server 10 estimates the power demand of the entire building for each time frame within the above-mentioned predetermined period. For example, the server 10 can estimate the power demand of the entire building based on the first power consumption data based on the meteorological information and the performance value of the power consumption generated by the load 40 included in the equipment performance data. As described above, the server 10 uses the first power consumption data based on the indoor information, thereby improving the estimation accuracy of the power demand.

[0085] In S13, the server 10 calculates the remaining power for each time frame within the above-mentioned prescribed period based on the generated power calculated in S11 and the power demand calculated in S12. Fig. 9 As described in , the power demand is subtracted from the generated power to calculate the surplus power.

[0086] In S14, the server 10 determines whether surplus power is generated. If the power demand is greater than the generated power during the above-mentioned prescribed period and surplus power is not generated ("No" in S14), the server 10 ends a series of processes without executing the following processes. If surplus power is generated during at least a part of the above-mentioned prescribed period ("Yes" in S14), the server 10 advances the process to S15.

[0087] In S15, the server 10 extracts one or more devices that can store surplus power (energy equivalent to the surplus power) from the plurality of energy storage devices 30 as candidates based on the required power and required period determined for each energy storage device 30. Fig.10 The description is described in detail in , so it will not be repeated here.

[0088] In S16, the server 10 calculates the actual cost reduction amount taking into account the energy loss generated from storing energy to supplying energy for each candidate extracted in S15. Fig.11 The detailed description is given in , so it will not be repeated.

[0089] In S17, the server 10 determines the device with the largest actual cost reduction amount from one or more candidates as the storage destination of the surplus power. In addition, for example, when there are multiple candidates, the server 10 can determine other devices with large actual cost reduction amounts (such as the device with the second largest actual cost reduction amount) as the storage destination of the surplus power in addition to the device with the largest actual cost reduction amount. In addition, for example, when the surplus power is large, the server 10 can also determine two or more devices with large actual cost reduction amounts as the storage destination of the surplus power.

[0090] As described above, in the present embodiment, one or more energy storage devices 30 that satisfy the conditions related to the required power and the required period are extracted from the plurality of energy storage devices 30. As a result, the surplus power can be efficiently stored in the extracted energy storage device 30. In more detail, since efficient energy conversion is performed in the extracted energy storage device 30, energy loss is small. Therefore, the stored energy can be increased and the amount of energy loss can be reduced. Therefore, according to the present embodiment, energy saving and economy in a building can be achieved at the same time.

[0091] Variation example.

[0092] In this modification, a configuration for more efficiently storing surplus power by executing energy-saving control of a building will be described.

[0093] Fig.13 This is a diagram for explaining a method of extracting candidates of energy storage devices 30 for storing surplus power in a modified example. The server 10 can perform energy-saving control of a building (load 40 of BEMS 1) by controlling, for example, air conditioning equipment, lighting equipment, or elevators. When the power consumption of the entire building is suppressed by energy-saving control, the surplus power increases accordingly.

[0094] exist Fig.10 In FIG. 1 , it is shown that device A is not extracted as a candidate. This is because the remaining power P4 in time frame t4 does not meet the required power Pa, and efficient energy conversion cannot be achieved. However, if Fig.13 As shown in FIG. 1 , when the surplus power is increased by energy-saving control, the surplus power P4 in the time frame t4 may exceed the required power Pa. Accordingly, since efficient energy conversion can also be achieved in device A, device A is also extracted as a candidate. In this way, by increasing the surplus power by energy-saving control, the number of candidates of one or more energy storage devices 30 that meet the conditions related to the required power and the required period can be increased.

[0095] Fig.14 The flowchart shows the processing procedure of the calculation process related to the surplus power in the modification. The processing of S21 and S22 is similar to the processing of S11 and S12 in the embodiment (see Fig.12 )same.

[0096] In S23, the server 10 determines whether the power generated by the naturally variable power source 20 and / or the power demand of the entire building satisfies the specified conditions. For example, the server 10 may determine that the condition is satisfied when the power generated does not satisfy the first reference amount, or may determine that the condition is satisfied when the power demand exceeds the second reference amount, or may determine that the condition is satisfied when the power generated does not satisfy the first reference amount and the power demand exceeds the second reference amount. When the condition is satisfied ("Yes" in S23), the server 10 causes the processing to enter S24. In addition, when the condition is not satisfied ("No" in S23), the server 10 skips the processing of S24 and causes the processing to enter S25.

[0097] In S24, the server 10 performs energy-saving control of the building (load 40 of BEMS1). Energy-saving control may be the suppression of air volume in air-conditioning equipment, the change of set temperature, or the suppression of irradiation range and light quantity in lighting equipment. Energy-saving control may be, for example, intermittent operation of lifts (elevators, escalators, etc.) or power-saving control of OA equipment. Since the processing after S25 is the same as the processing after S13 in the embodiment, the description will not be repeated.

[0098] In addition, although not shown, the server 10 may also increase the amount of energy stored in the energy storage device 30 in preparation for the occurrence of a meteorological disaster compared to a normal time (a case where a meteorological disaster forecast is not received) when a meteorological disaster forecast (warning or alarm related to typhoons, heavy rain, floods, heavy snow, strong winds, heat waves, cold waves, lightning strikes, etc.) is received from the external server 6. That is, the server 10 causes each of the plurality of energy storage devices 30 to store energy exceeding the first prescribed amount when no meteorological disaster forecast is received. On the other hand, when a meteorological disaster forecast is received, the server 10 causes each of the plurality of energy storage devices 30 to store energy exceeding the second prescribed amount that is larger than the first prescribed amount.

[0099] As described above, in this variant, similarly to the embodiment, one or more energy storage devices 30 that satisfy the conditions related to the required power and the required period are extracted from a plurality of energy storage devices 30. Thus, energy saving and economy in the building can be taken into account. Furthermore, in this variant, the surplus power is increased by energy-saving control of the building. Thus, the candidates for the storage destination of the surplus power can be increased. That is, more efficient energy conversion can be performed, and the possibility of extracting an energy storage device 30 with less energy loss as a candidate is increased. Therefore, energy saving and economy in the building can be taken into account at a higher level.

[0100] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0101] Description of symbols

[0102] 1: BEMS; 5: Central server; 6, 7: External servers; 8: Network; 9: Power system; 10: Server; 11: Processor; 12: Memory; 13: Input device; 14: Display; 15: Communication interface; 16: Database; 161: Equipment specification database; 162: Equipment performance database; 163: Meteorological database; 164: Indoor database; 165: Electricity fee database; 20: Natural variable power source; 30: Energy storage equipment; 31: Power storage equipment; 32: Heat storage equipment; 33: Hot water supply equipment; 40: Load; 50: Indoor management system; 101: Power generation estimation unit; 102: Power demand estimation unit; 103: Remaining power calculation unit; 104: Candidate extraction unit; 105: Cost calculation unit; 106: Equipment determination unit.

Claims

1. A server that manages the energy in a building, in which a natural variable power source whose power generation varies according to meteorological conditions and a plurality of energy storage devices that store energy in the form of electricity or heat respectively are provided. Among them, The server has a processor that executes arithmetic processing for determining which of the plurality of energy storage devices to store the power generation of the natural variable power source. When the power generation of the natural variable power source exceeds the power consumption of the building and surplus power is generated, the processor extracts from the plurality of energy storage devices one or more energy storage devices whose period when the surplus power exceeds a specified amount is longer than the period required to continuously store energy according to the specifications of the devices. The processor calculates, for each of the one or more energy storage devices, the amount of electricity cost reduction when the surplus power is stored in the energy storage device, and determines the energy storage device for storing the surplus power according to the reduction amount.

2. The server according to claim 1, Among them, The processor increases the energy storage devices extracted as the one or more energy storage devices by performing energy-saving control to suppress the power consumption of the building in such a way that the period when the surplus power exceeds the specified amount becomes longer.

3. The server according to claim 1 or 2, Among them, The processor calculates the reduction amount for each of the one or more energy storage devices according to the amount obtained by converting the energy stored in the energy storage device into electricity cost and the amount obtained by converting the energy loss generated until the surplus power stored in the energy storage device is consumed into electricity cost.

4. The server according to any one of claims 1 to 3, Among them, An access management system for managing the indoor information of people in each of a plurality of rooms in the building is further provided in the building. The processor estimates the power consumption of the building using the indoor information.

5. The server according to any one of claims 1 to 4, Among them, When no forecast of a meteorological disaster is received, the processor causes the plurality of energy storage devices to store the power generation of the natural variable power source in such a way that each of the plurality of energy storage devices stores energy exceeding a first specified amount. When the forecast is received, the processor causes the plurality of energy storage devices to store the power generation of the natural variable power source in such a way that each of the plurality of energy storage devices stores energy exceeding a second specified amount for preventing the occurrence of the meteorological disaster, and the second specified amount is larger than the first specified amount.

6. A building energy management system, Among them, The building energy management system includes: The server according to any one of claims 1 to 5; The natural variable power source; and The plurality of energy storage devices.

7. A building energy management method for managing the energy in a building, in which a natural variable power source whose power generation varies according to meteorological conditions and a plurality of energy storage devices that store energy in the form of electricity or heat respectively are provided in the building. Among them, the building energy management method includes the following steps: Determine whether the power generation power of the natural variable power source exceeds the consumption power of the building to generate surplus power; In the case of generating the surplus power, extract one or more energy storage devices from the plurality of energy storage devices, in which the period during which the surplus power exceeds a specified amount is longer than the period during which energy needs to be continuously stored; And For each of the one or more energy storage devices, calculate the reduction amount of electricity charges when the surplus power is stored in the energy storage device, and determine the energy storage device for storing the surplus power according to the reduction amount.

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