AIR CONDITIONING CONTROL DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of PCT Application No. PCT/JP2024/009090, filed Mar. 8, 2024 and based upon and claiming the benefit of priority from Japanese Patent Application No. 2023-113812, filed Jul. 11, 2023, the entire contents of all which are incorporated herein by reference.

FIELD

An embodiment of the present invention relates generally to an air conditioning control device.

BACKGROUND

In offices and other buildings, air conditioning-related energy consumption accounts for approximately 40% of the energy consumed by the entire facilities. For this reason, promoting energy saving related to air conditioning contributes greatly to energy saving in the entire facilities. As a result, a large number of air conditioning control devices for promoting energy saving related to air conditioning have been proposed.

For example, for air conditioning systems in which outside air intake air conditioners and return air intake air conditioners are combined as air conditioning in medium-sized or larger buildings, a method of controlling an air conditioning system to promote energy saving in the entire air conditioning system including the heat source unit while considering the comfort of occupants in a room has been proposed. More specifically, the operations of the air conditioners and heat source units are controlled such that energy consumption is minimized within a predetermined comfort range, under a plurality of conditions when controlling the air conditioning system.

However, energy consumption may be reduced during the entire operation period by pre-cooling or pre-heating, depending on the future increase or decrease in the heat load on the room. To achieve further energy savings, it is necessary to create an operation plan that reflects changes over time in set values for the operation controls of air conditioners and heat source units.

The present invention has been made based on this, and aims to provide an air conditioning control device capable of achieving energy savings for the entire air conditioning system over a specific period of time in the future, for an air conditioning system which, after performing latent heat treatment in an outside air intake air conditioner, mixes the treated air with return air from inside the room, and performs sensible heat treatment on the mixed air in a return air intake air conditioner.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically showing a configuration of an air conditioning system according to an embodiment.

FIG. 2 is a block diagram schematically showing a functional configuration of the air conditioning control device according to the embodiment.

FIG. 3 is a psychrometric chart showing an example of state values of air controlled by the air conditioning control device according to the embodiment.

FIG. 4 is a flowchart showing a flow of an operation plan determination process performed in the air conditioning control device according to the embodiment.

FIG. 5 is a table showing an example of output of predicted values of heat load at each time in each indoor space (control zone) in a case where state fluctuation information from time 1 to N in a predetermined future period is input in the air conditioning control device according to the embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, an air conditioning control device according to one embodiment controls the air conditioning of an air conditioning system comprising at least one or more first air conditioners, at least one or more second air conditioners, a first air conditioner control device, and a second air conditioner control device. The first air conditioner performs a latent heat treatment on air including outside air for each indoor space controlled to be air conditioned. The second air conditioner performs a sensible heat treatment on mixed air obtained by mixing the treated air after the latent heat treatment with return air from the indoor space. The first air conditioner control device controls operations of the first air conditioner. The second air conditioner control device controls operations of the second air conditioner.

The air conditioning control device comprises an optimal operation plan function creation unit, a load fluctuation value calculation unit, an operation plan determination unit, and an operation plan transmission unit. The optimal operation plan function creation unit calculates in advance, by optimization calculation, an operation plan that represents changes in set values for controlling the air conditioning system so as to satisfy a range of a comfort index representing comfort of the indoor space and minimize the total energy consumption of the entire air conditioning system in the predetermined period for each combination of a value indicating the state of outside air under a plurality of conditions in a future predetermined period and a value indicating the indoor heat load for each indoor space under the plurality of conditions, for a plurality of types of the set values, and creates an optimal operation plan function, which is a function for determining the operation plan under all of the plurality of conditions for each type of the set values. The load fluctuation value calculation unit calculates a fluctuation value of the indoor heat load of the indoor space for the predetermined period, based on state fluctuation information including weather information. The operation plan determination unit specifies the set value corresponding to the fluctuation value of the indoor heat load for the predetermined period calculated by the load fluctuation value calculation unit, based on the optimal operation plan function created by the optimal operation plan function creation unit. The operation plan transmission unit transmits the set value specified by the operation plan determination unit to the first air conditioner control device and the second air conditioner control device.

An embodiment of the present invention will be described hereinafter with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing a configuration of an air conditioning system 1 according to a present embodiment. The air conditioning system 1 controls air conditioning of space to be air conditioned (hereinafter referred to as a room) 10 such as an office building. In recent years, office buildings have good insulation and are equipped with a large number of OA devices such as personal computers and printers, and air conditioning is often controlled in a cooling mode throughout the year. For this reason, in the present embodiment, as an example, it is assumed that the air conditioning system 1 controls air conditioning of the room 10 in a cooling (cool) mode. However, the air conditioning system 1 can also control air conditioning of the room 10 in a heating (heating) mode, and air conditioning control can be performed by appropriately switching between the cooling mode and the heating mode.

As shown in FIG. 1, the air conditioning system 1 comprises an air conditioning control device 100, and the air conditioning of the room 10 is controlled by the air conditioning control device 100. The air conditioning control device 100 includes, for example, a CPU, a memory, a storage device (nonvolatile memory), an input/output circuit, a timer, a display, and the like, and performs predetermined calculation processing. In the present embodiment, the air conditioning control device 100 assigns predetermined setting values to an outside air intake air conditioner control device 201, a heat source unit control device 301, and a return air intake air conditioner control device 401. Although details will be described later, the predetermined setting values are values which are preset to optimally operate the air conditioning devices 200, 300, and 400 controlled by the outside air intake air conditioner control device 201, the heat source unit control device 301, and the return air intake air conditioner control device 401, respectively. The air conditioning device is an air conditioner, a heat source unit, or the like that constitutes the refrigeration cycle in the air conditioning system 1.

Similarly to the air conditioning control device 100, these control devices 201, 301, and 401 include, for example, a CPU, a memory, a storage device (nonvolatile memory), an input/output circuit, a timer, a display, and the like, and perform predetermined calculation processing. Details of the calculation process according to the present embodiment, which is performed by the air conditioning control device 100, will be described later.

The outside air intake air conditioner control device (first air conditioner control device) 201 controls the operations of the outside air intake air conditioner (first air conditioner) 200, which cools and dehumidifies the outside air. The heat source unit control device 301 controls the operations of the heat source unit 300 which generates cold or hot water (cold water in the present embodiment) to be used by the outside air intake air conditioner 200. The return air intake air conditioner control device (second air conditioner control device) 401 controls the operations of the return air intake air conditioner (second air conditioner) 400 which introduces air (indoor air) in the room 10 to air condition the room 10.

For example, in a large office building or the like, since the room is large and the room is divided into a plurality of spaces such that air-conditioning is performed to correspond to each of the spaces (control zones), a plurality of air conditioners are installed. In the following descriptions, for convenience, each of the plurality of control zones obtained by dividing the room in this manner will also be treated as a room 10. The control zone is a space whose air conditioning is controlled by the return air intake air conditioner 400.

The outside air intake air conditioner control device 201 obtains a blowing temperature set value (hereinafter referred to as an outside air intake air conditioner blowing temperature set value) and an air volume set value (hereinafter referred to as an outside air intake air conditioner air volume set value) of the outside air intake air conditioner 200 from the air conditioning control device 100. The outside air intake air conditioner blowing temperature set value is a value which is set as the temperature of the air blown out from the outside air intake air conditioner 200. The outside air intake air conditioner blowing air volume set value is a value which is set as the volume of the air blown out from the outside air intake air conditioner 200.

The outside air intake air conditioner control device 201 controls the blowing temperature of the outside air intake air conditioner 200 by adjusting the opening of a cold water valve 203, based on the outside air intake air conditioner outlet temperature set value and a value measured by a first supply air thermometer 202. The first supply air thermometer 202 measures the temperature of the air blown out from the outside air intake air conditioner 200 and supplied to the return air intake air conditioner 400. The cold water valve 203 adjusts the flow rate of cold water guided from the heat source unit 300 to the outside air intake air conditioner 200.

The outside air intake air conditioner 200 mainly comprises a water heat exchanger 200a and a fan (hereinafter referred to as a supply air fan) 200b, and performs latent heat treatment on the outside air for each room 10 and, in the present embodiment, cools and dehumidifies the outside air. The outside air intake air conditioner 200 is connected to the heat source unit 300 and the return air intake air conditioner 400 by predetermined liquid pipes and gas pipes. Incidentally, the outside air intake air conditioner 200 may also perform a latent heat treatment on the air which contains outside air, for example, mixed air of the air returned from the room 10 and the outside air. In addition, at least one outside air intake air conditioner 200 may be installed for each room 10. The water heat exchanger 200a performs heat exchange (latent heat treatment) between the cold water guided from the heat source unit 300 and the outside air. The supply air fan 200b draws the outside air into the outside air intake air conditioner 200 through the water heat exchanger 200a, and blows the air subjected to the latent heat treatment out of the outside air intake air conditioner 200 and supplies the air to the return air intake air conditioner 400. Incidentally, the air inside the outside air intake air conditioner 200 is supplied to the return air intake air conditioner 400, and is also exhausted to the outside by, for example, an exhaust fan (not shown).

In the present embodiment, the outside air intake air conditioner 200 supplies the air subjected to the latent heat treatment (cooled and dehumidified air) to the return air intake air conditioner 400, based on the outside air intake air conditioner air volume set value. In the example shown in FIG. 1, air is supplied from the outside air intake air conditioner 200 to the return air intake air conditioner 400 via a variable air volume (VAV) 500. However, air may also be supplied directly from the outside air intake air conditioner 200 to the return air intake air conditioner 400 without passing through the VAV 500.

The air volume of the VAV 500 is adjusted by controlling the opening of the VAV 500 based on a VAV air volume set value acquired by a VAV control device 501 from the air conditioning control device 100. At this time, the air volume of the VAV 500 can also be adjusted by controlling the damper opening of the VAV 500 such that the CO₂ concentration in the room 10 is constant. Incidentally, the air volume of the air blown from the outside air intake air conditioner 200 to the VAV 500 by the supply air fan 200b is controlled based on the outside air intake air conditioner air volume set value acquired from the air conditioning control device 100 by the outside air intake air conditioner control device 201. However, such an air volume may be controlled to a constant value or may be controlled according to the air volume of the VAV 500.

The heat source unit control device 301 acquires a generated water temperature set value or, in the present embodiment, a cold water temperature set value, from the air conditioning control device 100. The cold water temperature set value is a value which is set as the temperature of the cold water (heat medium) supplied from the heat source unit 300 to the outside air intake air conditioner 200. The heat source unit 300 adjusts capacity of a compressor (not shown) of the heat source unit 300 based on the cold water temperature set value to control the cold water temperature, and generates cold water to be used for the latent heat treatment of the outside air in the outside air intake air conditioner 200. The generated cold water is sent to the outside air intake air conditioner 200 by, for example, a pump device (not shown) of the heat source unit 300. Incidentally, in the present embodiment, since it is assumed that the air conditioning system 1 controls air conditioning in the cooling (cooling) mode, the heat source unit 300 generates cold water. However, when the air conditioning system 1 controls air conditioning in heating (heating) mode, the heat source unit 300 generates hot water.

The return air intake air conditioner control device 401 obtains the blowing temperature set value (hereinafter referred to as a return air intake air conditioner blowing temperature set value) and the air volume set value (hereinafter referred to as a return air intake air conditioner air volume set value) of the return air intake air conditioner 400 from the air conditioning control device 100. The return air intake air conditioner blowing temperature set value is a value which is set as the temperature of the air blown out from the return air intake air conditioner 400. The return air intake air conditioner air volume set value is a value which is set as the air volume of the air blown out from the return air intake air conditioner 400.

The return air intake air conditioner 400 comprises an air heat exchanger 400a and a fan (hereinafter referred to as a return air fan) 10b as its main elements, and performs a sensible heat treatment on the air (hereinafter referred to as mixed air) that is a mixture of air returned from the room 10 (hereinafter referred to as indoor return air) and the supply air from the outside air intake air conditioner 200, i.e., the processed air subjected to the latent heat treatment, for each room 10. At least one return air intake air conditioner 400 may be installed for each room 10. In the example shown in FIG. 1, the air heat exchanger 400a is mounted on the return air intake air conditioner 400, and the return air fan 10b is provided in the room 10. Instead of this or in addition to this, a fan may be provided in the return air intake air conditioner 400. The return air intake air conditioner 400 is connected to the return air intake air conditioner outdoor unit 404 by a predetermined liquid refrigerant pipe and a gas refrigerant pipe. The return air intake air conditioner outdoor unit 404 comprises, for example, a compressor, an air heat exchanger, and a fan (all not shown), as its components, and exchanges heat between the refrigerant and the outside air.

In the present embodiment, the return air intake air conditioner 400 draws in indoor return air based on the return air intake air conditioner air volume set value, and mixes the air with the supply air from the outside air intake air conditioner 200, for example, in the return air duct of the return air intake air conditioner 400. The return air intake air conditioner control device 401 adjusts an opening of a refrigerant valve 403, based on the return air intake air conditioner blowing temperature set value and the value measured by the second supply air thermometer 402. The second supply air thermometer 402 measures the temperature of the air (supply air) blown out from the return air intake air conditioner 400 and supplied to the room 10. The refrigerant valve 403 adjusts the amount of the refrigerant guided from the return air intake air conditioner outdoor unit 404 to the return air intake air conditioner 400 by the opening. The refrigerant guided to the return air intake air conditioner 400 exchanges heat with the mixed air in the air heat exchanger 400a.

The return air intake air conditioner control device 401 controls the temperature of the air blown from the return air intake air conditioner 400 towards the room 10 by the degree of the heat exchange between the mixed air and the refrigerant in the air heat exchanger 400a, for example, the opening of the refrigerant valve 403. Incidentally, the return air intake air conditioner control device 401 may control the room temperature by, for example, acquiring an indoor temperature set value from the air conditioning control device 100 and adjusting the opening of the refrigerant valve 403 based on an indoor temperature sensor installed in the room 10.

In addition to the configuration described above, when the return air intake air conditioner 400 and the return air intake air conditioner outdoor unit 404 are connected in a one-to-one relationship, the refrigerant valve 403 may not be provided, and the return air intake air conditioner control device 401 may be connected to the return air intake air conditioner outdoor unit 404. In this case, the indoor temperature may be controlled by, for example, controlling the return air intake air conditioner outdoor unit 404 to adjust the refrigerant temperature, pressure, flow rate, and the like.

The outside air intake air conditioner control device 201, the heat source unit control device 301, the return air intake air conditioner control device 401, and the VAV control device 501 may control the start/stop state, the operation mode, and the like of each air conditioner that they control.

Next, functions of the air conditioning control device 100 will be described.

FIG. 2 is a block diagram schematically showing a functional configuration of the air conditioning control device 100. The air conditioning control device 100 is configured as an information processing device such as a personal computer or a server. For example, the air conditioning control device 100 reads various data with an input/output circuit, and performs an operation plan determination process in a CPU using a program read from a storage device to a memory. The operation plan determination process is a process performed to determine an operation plan for the air conditioning system 1 in the present embodiment. Then, the air conditioning control device 100 assigns predetermined set values to the outside air intake air conditioner control device 201, the heat source unit control device 301, the return air intake air conditioner control device 401, and the VAV control device 501 for operating each of the air conditioners controlled by them, according to the result of the performed operation plan determination process.

In the present embodiment, as an example, the air conditioning control device 100 is assumed to assign the outside air intake air conditioner outlet temperature set value to the outside air intake air conditioner control device 201, the cold water temperature set value to the heat source unit control device 301, the return air intake air conditioner outlet temperature set value and the return air intake air conditioner air volume set value to the return air intake air conditioner control device 401, and the VAV air volume set value to the VAV control device 501. Incidentally, when the air conditioning system 1 controls air conditioning in the heating (heating) mode, the air conditioning control device 100 assigns the hot water temperature set value to the heat source unit control device 301 as the generated water temperature set value. In addition, the air conditioning control device 100 may also assign a value indicating the on/off state of the outside air intake air conditioner 200 to the outside air intake air conditioner control device 201, and a value indicating the on/off state of the return air intake air conditioner 400 to the return air intake air conditioner control device 401.

As shown in FIG. 2, the air conditioning control device 100 includes an offline processing unit 101 and an online processing unit 102. When performing the operation plan determination process, the air conditioning control device 100 creates an optimal operation plan function to be described later, in the offline state. The offline state is a state in which the air conditioning control device 100 does not input or output (send or receive) data via the communication unit 103 or the input unit 104. In other words, in the offline state, the outside air intake air conditioner 200, the heat source unit 300, the return air intake air conditioner 400, the VAV 500, and the other external devices are disconnected in terms of data communication from the air conditioning control device 100.

The offline processing unit 101 operates even when the air conditioning control device 100 is offline, and includes an air conditioning model storage unit 105, an optimization calculation unit 106, an optimal operation plan function creation unit 107, and an optimal operation plan function storage unit 115. In the present embodiment, as an example, the offline processing unit 101 is assumed to operate when the air conditioning control device 100 is in an offline state, but can operate when the air conditioning control device 100 is in an online state, and the condition for operation is not limited to the offline state. The online state is a state in which the air conditioning control device 100 inputs and outputs (transmits and receives) data via the communication unit 103 and the input unit 104 as described below.

The air conditioning model storage unit 105 is, for example, a nonvolatile memory, and stores information related to the air conditioning model. The air conditioning model is a model which can calculate possible values of parameters such as the power consumption and air conditioning load calculated when the air conditioning system is operated with predetermined set values, for example, the outside air intake air conditioner outlet temperature set value, the cold water temperature set value, the return air intake air conditioner outlet temperature set value, the return air intake air conditioner air volume set value, and the VAV air volume set value, for the device configuration of the air conditioning system 1 and the state values inside and outside the room 10. The air conditioning model storage unit 105 functions as a database which stores these air conditioning models.

A model of the power consumption of the outside air intake air conditioner 200 is expressed by, for example, the following equation (1). Incidentally, in the equation (1), {circumflex over ( )} indicates a power (and also in equation (3)).

Power ⁢ consumption ⁢ of ⁢ outside ⁢ air ⁢ intake ⁢ air ⁢ conditioner ⁢ fan = fan ⁢ rated ⁢ power ⁢ consumption × ( supply ⁢ air ⁢ volume / fan ⁢ rated ⁢ air ⁢ volume ) ^ 3 ( 1 )

A model of the power consumption of the heat source unit 300 is expressed by, for example, the following equations (2) and (3).

Power ⁢ consumption ⁢ of ⁢ heat ⁢ source ⁢ device ⁢ cooling = outside ⁢ conditioning ⁢ unit ⁢ system ⁢ cooling ⁢ heat ⁢ amount / heat ⁢ source ⁢ device ⁢ cooling ⁢ efficiency ( 2 ) Power ⁢ consumption ⁢ of ⁢ heat ⁢ source ⁢ pump = pump ⁢ rated ⁢ power ⁢ consumption × ( pump ⁢ flow ⁢ rate / pump ⁢ rated ⁢ flow ⁢ rate ) ^ 3 ( 3 )

A model of the power consumption of the return air intake air conditioner 400 is expressed by, for example, the following equation (4).

Power ⁢ consumption ⁢ of ⁢ return ⁢ air ⁢ intake ⁢ air ⁢ conditioner = outdoor ⁢ unit ⁢ rated ⁢ power ⁢ consumption × load ⁢ factor × outdoor ⁢ unit ⁢ efficiency + power ⁢ consumption ⁢ of ⁢ indoor ⁢ unit ( 4 )

The efficiency values, the rated values, and the like in these equations (1) to (4) may be catalog values for each air conditioning device or may be values calculated based on state information such as the outside air temperature. For example, values such as a coefficient of performance (COP) can be applied as the efficiency.

FIG. 3 is a psychrometric chart showing an example of state values of air according to the present embodiment. As shown in FIG. 3, first, the outside air intake air conditioner 200 cools and dehumidifies the outside air based on the outside air intake air conditioner outlet temperature set value (t1). Next, the processed air (air supplied from the outside air intake air conditioner 200 to the return air intake air conditioner 400) and the indoor return air (air returning from the room 10 to the return air intake air conditioner 400) are mixed to become mixed air. At this time, a dry bulb temperature and an absolute humidity of the mixed air can be calculated from the supply air state of the outside air intake air conditioner 200 and the return air state of the room 10, based on the VAV air volume set value and the return air intake air conditioner air volume set value.

Finally, the return air intake air conditioner 400 cools the mixed air based on the return air intake air conditioner outlet temperature set value (t2) and supplies the air to the room 10. In the air conditioning system 1 of the present embodiment, the temperature and the humidity of the air supplied to the room 10 can be controlled to a predetermined value by providing any combination of the outside air intake air conditioner outlet temperature set value, the chilled water temperature set value, the return air intake air conditioner outlet temperature set value, the return air intake air conditioner air volume set value, and the VAV air volume set value.

Moreover, the air conditioner sensible heat load for the room 10 is expressed by, for example, the following equation (5).

Air ⁢ conditioner ⁢ sensible ⁢ heat ⁢ load = ( room ⁢ temperature - return ⁢ air ⁢ intake ⁢ air ⁢ conditioner ⁢ supply ⁢ air ⁢ temperature ) × air ⁢ specific ⁢ heat × supply ⁢ air ⁢ volume ( 5 )

In equation (5), the sensible heat load caused by the air supplied by the return air intake air conditioner 400 is calculated, but the latent heat load can also be calculated using an air conditioning model in a similar manner. By using these air conditioning models, it is possible to calculate the energy consumption of the air conditioning system 1 for the specified set values for the outside air temperature, outside air humidity, heat load of the room 10, and each air conditioning device, as well as the inflow amounts of air, moisture, and heat amount into the room 10.

The optimization calculation unit 106 calculates a predetermined set value at each time within a predetermined period by using the air conditioning models. The set value is calculated for each combination of a plurality of conditions, more specifically, a plurality of input conditions inside and outside the room 10 (hereinafter simply referred to as input conditions), such that the total energy consumption of the entire air conditioning system 1 becomes minimum, while maintaining the range of the indoor condition values of the room 10. The predetermined period is a period which is continuous in a predetermined length in the future, and is arbitrarily set, for example, on an hourly or daily basis. The input conditions are prerequisite conditions for calculating the set values, and are set for each time within a predetermined period (hereinafter simply referred to as each time), for example, as a combination of a value indicating the outside air state under a plurality of conditions and a value indicating the indoor heat load for each room 10 under the plurality of conditions. The outside air temperature and the outside air humidity are applied as values indicating the outside air state.

In the present embodiment, the optimization calculation unit 106 calculates the optimal combination at each time of the outside air intake air conditioner blowing temperature set value, the cold water temperature set value, the return air intake air conditioner blowing temperature set value, the return air intake air conditioner air volume set value, and the VAV air volume set value, for a plurality of input conditions. The optimal combination is a combination which minimizes the total energy consumption of the entire air conditioning system 1.

As regards the input conditions for each time inside and outside the room 10, all combinations of values within a specified range for the outdoor temperature and the outdoor humidity of the room 10 and the heat load (indoor heat load) of the room 10 may be used, or fluctuations in outdoor conditions based on past weather data or the heat load pattern of the room 10 may be used. The heat load pattern of the room 10 can be created by changing the heat load value for each time within an arbitrary range based on, for example, the time series changes in the maximum daily heat load of the room 10 listed in a heat load calculation sheet or changes in the past heat load. In addition, the indoor heat load represents, as an example, the total heat load on the room 10 excluding the air conditioning load. The indoor heat load represents, for example, the total of the through load, outdoor load, solar radiation load, and other internal heat generation loads due to heat from the human body and OA devices.

For example, the change in state quantity of the room 10 and the energy consumption of the entire air conditioning system 1 in a case where a predetermined set value corresponding to each time is given to a specific combination of the outside air temperature fluctuation value, the outside air humidity fluctuation value, and the heat load fluctuation value can be calculated using an air conditioning model. The change ΔT in the indoor temperature of the room 10, which changes sequentially for each time step Δt, for the input conditions and the specific set value at each time is expressed by, as an example, the following equation (6).

Δ ⁢ T = ( ( indoor ⁢ sensible ⁢ heat ⁢ load + air ⁢ conditioner ⁢ sensible ⁢ heat ⁢ load ) × Δ ⁢ t ) / indoor ⁢ heat ⁢ capacity ( 6 )

Regarding the amount of heat flowing into the room 10, the indoor temperature in the room 10 at each time for the heat load and the air conditioning load can be obtained by obtaining the thermodynamic thermal equilibrium state using the equation (6) and the air conditioning model. At this time, similarly to the amount of air and moisture, the change in the state quantity in the room 10 at each time can be calculated by searching for the equilibrium state of the refrigerant in the room 10.

In addition, the total energy consumption of the entire air conditioning system 1 in the present embodiment is expressed by the following equation (7). In other words, as shown in the equation (7), the total energy consumption of the entire air conditioning system 1 is a value obtained by summing up the amounts of power of the outside air intake air conditioner 200, the heat source unit 300, and the return air intake air conditioner 400 at each time during a predetermined period.

[ Equation ⁢ 7 ] Energy ⁢ consumption ⁢ of ⁢ entire ⁢ air ⁢ conditioning ⁢ system = ∑ Time Predetermined ⁢ period ( Power ⁢ consumption ⁢ of ⁢ outside ⁢ air ⁢ intake ⁢ air ⁢ conditioner + power ⁢ consumption ⁢ of ⁢ heat ⁢ source ⁢ unit + power ⁢ consumption ⁢ of ⁢ return ⁢ air ⁢ intake ⁢ air ⁢ conditioner ) ( 7 )

As described above, the optimization calculation unit 106 calculates an optimal combination of set values at each time, which minimize the total energy consumption of the entire air conditioning system 1 under a plurality of input conditions. In this case, the set values at each time which minimize the total energy consumption of the entire air conditioning system 1 in the equation (7), can be searched for by any method. For example, a simulation may be performed in which all set values at each time are changed within a predetermined range to find the combination of the set values at which the energy consumption becomes minimum or a publicly known combined optimization algorithm may be used.

A comfort index of the room 10, the amount of outside air intake, and the like are included in the condition values in the room 10 among the input conditions. The comfort index is an index determined from the temperature, humidity, and wind speed in the room 10, i.e., an index which indicates the comfort of the room 10 and, for example, a discomfort index can be applied. In the present embodiment, an index of comfort corresponding to at least the temperature and humidity in the room 10 is used as the comfort index. In this case, in the calculation of the state quantities in the room 10 using the air conditioning model, since the state quantities related to the air and moisture in the room 10 at each time are calculated, it is possible to determine whether the room 10 satisfies a predetermined range of discomfort index. However, the comfort index is not limited to the discomfort index and, for example, a predicted mean vote (PMV) based on the air volume calculated by the air conditioning model or the like, an effective temperature, and the like, may be used. In addition, in the present embodiment, the amount of outside air intake in the room 10 is equal to the air volume of the VAV 500.

The optimal operation plan function creation unit 107 creates an optimal operation plan function. The optimal operation plan function is a function which passes through the set values at each time, and is created for all combinations of optimal set values for the input conditions calculated by the optimization calculation unit 106.

More specifically, for each combination of the fluctuation value of the value indicating the outside air state among a plurality of input conditions in a predetermined period (a period continuing for a predetermined length in the future) with the fluctuation value of the value indicating the indoor heat load for each room 10 of the input conditions, the optimal operation plan function is created so as to satisfy the range of the comfort index of the room 10. In addition, the optimal operation plan function is a function for determining the operation plan of the air conditioning system 1 calculated in advance by optimization calculation. The operation plan of the air conditioning system 1 represents the change in the set values which control the air conditioning system 1 such that the total energy consumption of the entire air conditioning system 1 becomes minimum in a predetermined period, and is defined simply as a set of the set values. The operation plan is calculated for a plurality of types of set values. The optimal operation plan function creation unit 107 creates an optimal operation plan function for each type of set value.

For example, the optimal operation plan function is created to satisfy at least a first condition among a first condition that is satisfied when the comfort index for the room 10 is within a range of an appropriate value, and a second condition that is satisfied when a predetermined outside air intake amount set value is within a range of an appropriate value. In other words, the optimal operation plan function only needs to satisfy the first condition alone or to satisfy both the first and second conditions. However, the optimal operation plan function may be created for a combination of optimal set values for condition values in the room 10, among the plurality of input conditions.

The optimal operation plan function creation unit 107 writes the created optimal operation plan function to the optimal operation plan function storage unit 115. The optimal operation plan function storage unit 115 is, for example, a nonvolatile memory, and stores the optimal operation plan function in association with the input conditions.

In the present embodiment, by creating an optimal operation plan function in the offline processing unit 101, it is possible to calculate the combination of optimal set values at each time for combinations of outside air temperature fluctuation values, outside air humidity fluctuation values, and heat load fluctuation values under a plurality of conditions with a plurality of input conditions (or condition values within the room 10 among the input conditions).

The online processing unit 102 operates when the air conditioning control device 100 is online, and includes a communication unit 103, an input unit 104, and a control unit 108. The online state is a state in which the air conditioning control device 100 inputs and outputs (transmits and receives) data via the communication unit 103 and the input unit 104. In other words, in the online state, the outside air intake air conditioner 200, the heat source unit 300, the return air intake air conditioner 400, the VAV 500, and the other external devices are connected with the air conditioning control device 100 in terms of data communication.

The communication unit 103 is a network interface. The communication unit 103 communicates (sends and receives data) with the outside air intake air conditioner control device 201, the heat source unit control device 301, the return air intake air conditioner control device 401, and the VAV control device 501. The communication unit 103 acquires state fluctuation information such as the predicted outside air temperature, predicted outside air humidity, and the predicted number of occupants in each room 10 by communicating data with an external device that stores, for example, weather forecast information and output information of an occupancy prediction engine. In other words, the state fluctuation information is information that includes weather information or a predicted value of the number of occupants in each room 10.

The input unit 104 is configured using, for example, input devices such as a touch panel, a mouse, and a keyboard. When an indoor condition value set by the user (a condition value in the room 10 among the input conditions) is input from the input unit 104, the indoor condition value is transferred to the control unit 108. The indoor condition value may include the amount of outside air intake into the room 10 and the CO₂ concentration in the room 10 in addition to the comfort index range of the room 10. In this embodiment, the discomfort index range and the amount of outside air intake are input from the input unit 104 as the indoor condition values of the room 10 set by the user.

The control unit 108 performs an operation plan determination process. FIG. 4 is a flowchart showing a flow of the operation plan determination process performed by the control unit 108. To perform the operation plan determination process, the control unit 108 includes an indoor condition value acquisition unit 109, a state fluctuation information acquisition unit 110, a load fluctuation value calculation unit 111, an optimal operation plan function acquisition unit 112, an operation plan determination unit 113, and an operation plan transmission unit 114, as shown in FIG. 2. Each of these units 109 to 114 will be described below with reference to the flowchart of the operation plan determination process shown in FIG. 4, which is performed by the control unit 108.

In the operation plan determination process, the indoor condition value acquisition unit 109 first acquires the indoor condition value of the room 10 via the input unit 104 (step S101). The indoor condition value is, for example, input from the input unit 104 by the user. However, the indoor condition value may be a preset value. The indoor condition value acquisition unit 109 assigns the acquired indoor condition value to the optimal operation plan function acquisition unit 112.

In addition, the state fluctuation information acquisition unit 110 acquires state fluctuation information for a predetermined period (a period continuing for a predetermined length in the future) such as predicted outdoor temperature and predicted outdoor humidity via the communication unit 103 (step S102). Predicted solar radiation, predicted OA power consumption, predicted number of occupants in the room, and the like, which are required for input to the load change value calculation unit 111 may be included in the state fluctuation information. Publicly available weather forecast information or publicly known people flow prediction technology may be used to calculate the state fluctuation information. The state fluctuation information acquisition unit 110 assigns the acquired state fluctuation information to the load fluctuation value calculation unit 111.

The load fluctuation value calculation unit 111 calculates the heat load fluctuation value of the room 10 for the acquired state fluctuation information for the specified period (step S103). In other words, the load fluctuation value calculation unit 111 calculates the fluctuation value of the indoor heat load of the room 10 for the predetermined period, based on the state fluctuation information including weather information. The method of calculating the heat load fluctuation value is not particularly limited. The heat load fluctuation value may be calculated by, for example, a simulation using a calculation model for the heat load passing from the building envelope, the solar radiation heat load of windows, the heat generation load from the human bodies and OA devices, and the like, or may be calculated using a publicly known heat load prediction technique based on the state fluctuation information.

The heat load fluctuation value for a specified period calculated by the load fluctuation value calculation unit 111 is output in, for example, a form of a table as shown in FIG. 5. FIG. 5 shows an example of output of predicted values of heat load for each indoor space at each time in a case where the room 10 is divided into indoor spaces 1 to n corresponding to the control zones of each return air intake air conditioner 400 and where the state fluctuation information for a specified period from time 1 to N is input. In FIG. 5, the load fluctuation value calculation unit 111 calculates only the total indoor heat load or sensible heat load for a predetermined period, but the indoor latent heat load may also be calculated in a similar manner. The load fluctuation value calculation unit 111 assigns the calculated heat load fluctuation value to the operation plan determination unit 113.

Then, the optimal operation plan function acquisition unit 112 acquires the optimal operation plan function created by the offline processing unit 101 (step S104). The optimal operation plan function is created for each indoor condition value by the optimal operation plan function creation unit 107 and is stored in the optimal operation plan function storage unit 115. The optimal operation plan function acquisition unit 112 acquires the optimal operation plan function corresponding to the indoor condition value of the room 10 acquired in step S101. At this time, the optimal operation plan function acquisition unit 112 accesses the optimal operation plan function storage unit 115 using, for example, the indoor condition value as a key, and extracts and acquires the optimal operation plan function linked to the indoor condition value. The optimal operation plan function acquisition unit 112 assigns the acquired optimal operation plan function to the operation plan determination unit 113.

The operation plan determination unit 113 determines an operation plan by the optimal operation plan function acquired in step S104, based on the predicted outdoor temperature, the predicted outdoor humidity, and the load fluctuation value (step S105). In other words, the operation plan determination unit 113 specifies an operation plan that corresponds to the indoor heat load fluctuation value (heat load fluctuation value of the room 10) for the predetermined period calculated by the load fluctuation value calculation unit 111, based on the optimal operation plan function created by the optimal operation plan function creation unit 107.

At this time, the operation plan determination unit 113 specifies the optimal outside air intake air conditioner outlet temperature set value, the cold water temperature set value, the return air intake air conditioner outlet temperature set value, the return air intake air conditioner air volume set value, and the VAV air volume set value for each time. At this time, if there is no optimal operation plan function created in advance by the offline processing unit 101 that matches, for example, the fluctuation value of the outside air temperature or outside air humidity for a predetermined period or the load fluctuation value calculated in step S103, the optimal operation plan function to which these fluctuation values are most similar may be used. The operation plan determination unit 113 assigns the optimal outside air intake air conditioner outlet temperature set value, the cold water temperature set value, the return air intake air conditioner outlet temperature set value, the return air intake air conditioner air volume set value, and the VAV air volume set value for each specified time to the operation plan transmission unit 114 as an operation plan for the predetermined period. In other words, the operation plan is defined as a set of optimal set values at each time during the predetermined period.

Then, the operation plan transmission unit 114 transmits the determined operation plan to the control device of each air conditioning device via the communication unit 103 (step S106). More specifically, the operation plan transmission unit 114 transmits the set values specified by the operation plan determination unit 113 to the control device of each air conditioning device. The timing of transmitting the operation plan is not particularly limited. For example, the operation plan transmission unit 114 may transmit the operation plan at timing of a predetermined time, i.e., the optimal set values at the predetermined time for a predetermined period, or may transmit the operation plan for the predetermined period in advance.

The control device of each air conditioning device to which the operation plan is transmitted controls the operation of the air conditioning device to be controlled, according to the set values of the operation plan. In the present embodiment, the outside air intake air conditioner control device 201 controls the operations of the outside air intake air conditioner 200 according to the transmitted outside air intake air conditioner outlet temperature set value. The heat source unit control device 301 controls the operations of the heat source unit 300 according to the transmitted cold water temperature set value. The return air intake air conditioner control device 401 controls the operations of the return air intake air conditioner 400 according to the transmitted return air intake air conditioner outlet temperature set value and return air intake air conditioner air volume set value. The VAV control device 501 controls the operations of the VAV 500 according to the transmitted VAV air volume set value.

Thus, according to the present embodiment, it is possible to calculate an operation plan, more specifically, the set values of each air conditioning device, reducing the total energy consumption of the entire air conditioning system 1 over a predetermined period (a period continuous in a predetermined length in the future) while maintaining the indoor condition values of the room 10 set by the user, i.e., while satisfying the range of the comfort index. When creating the operation plan, an operation plan corresponding to future changes in the indoor heat load is determined using an optimal operation plan function created in advance in an offline manner. Therefore, every time the outside air conditions or indoor environment change, high-load optimization calculations or processes for calculating the set values do not need to be performed, and air conditioning control with a good efficiency can be performed stably.

Incidentally, in the above-described embodiment, the outside air intake air conditioner 200 cools the outside air with cold water guided from the heat source unit 300, but may also cool the outside air with a refrigerant guided from the return air intake air conditioner outdoor unit 404. The outside air intake air conditioner 200 may mix a part of the return air from the room 10 with the outside air via a damper, cool the mixed air with a direct expansion coil, and further cool the cooled air with cold water guided from the heat source unit 300.

In addition, in the present embodiment, assigning the set value of the amount of outside air intake as the indoor condition value has been described, but the present invention is not limited to this. For example, the amount of outside air intake can be controlled by the opening of the VAV 500 such that the CO₂ concentration in the room 10 is constant. In this case, an optimal operation plan function including the CO₂ concentration and the amount of outside air intake may be created in advance in the offline processing unit 101.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.