Patent Application
20160195290
Embodiments described herein relate generally to an air-conditioning controller configured to control an air-conditioning system.
Energy with regard to air conditioning occupies a half of energy consumed in a whole construction facility such as an office and a living space. Therefore, a promotion of energy conservation with regard to an air-conditioning control greatly contributes saving of energy in the whole construction facility.
In view of such a situation, PTL 1 (JP 2004-069134 A) describes a technique using an air-conditioning control system for operating air conditioning so as to achieve optimum energy saving in the construction facility.
Due to the technique of PTL 1, it is possible to operate air conditioning with high efficiency energy saving by calculating a coil temperature object value of an air-conditioning coil and a cold/hot water temperature object value of a heat source device so that each air-conditioning required-consumption energy, including consumption energy of the heat source device for generating cold/hot water, consumption energy of a fan for delivering air treated with heat exchange by the air-conditioning coil, and consumption energy of a pump for delivering the cold/hot water from the heat source device, is configured to be minimum energy.
According to an embodiment, an air-conditioning controller configured to control an air-conditioning system including a heat source device that supplies a refrigerant for cooling air to an air conditioner includes: a measured value obtaining unit for obtaining a temperature measured value or a humidity measured value according to an air-conditioning subject; a comfort index range recorder for storing a target range of a comfort index of a sensation of warmth of human; a comfort index calculator for calculating the comfort index based on the temperature measured value or the humidity measured value, and an airflow speed according to the air-conditioning subject; a blast fan controller configured to control changing a wind speed from a blast fan to high when the comfort index calculated by the comfort index calculator is out of the target range stored in the comfort index range recorder, the blast fan circulating air cooled by the air conditioner towards the air-conditioning subject, the wind speed corresponding to the airflow speed that is a variable according to the comfort index; and a consumption energy controller configured to control the heat source device to decrease consumption energy after changing the wind speed.
A description will be made below of embodiments of an air-conditioning control system of the present application with reference to the drawings. Many recent constructions such as an office building have high thermal insulation property, and have many PCs and OA equipments. Therefore, the buildings are usually under a cooling operation throughout the year. Thus, a description will be made of a case of operating air-conditioning controlling mainly with a cooling operation in the following embodiments.
In a case of a large building, a size of each room is large. Therefore, a room is divided into a plurality of control zones, and a plurality of air conditioners corresponding to each of the control zones are installed in a mechanical room adjacent to the room. Hereinafter, even in such a case, each of the control zones is referred to as a room for convenience.
The air-conditioning control system 1 is configured to air-condition in a building A subject to air conditioning. The air-conditioning control system 1 includes air conditioners 10 installed in each room in the building A, temperature sensors 20 provided in each room to measure room temperature so as to send each measured value to each of the air conditioners 10, humidity sensors 30 provided in each room to measure room humidity so as to send each measured value to each of the air conditioners 10, a central heat source device 40 for controlling cold water supplied to each of the air conditioners 10, and a air-conditioning linkage controller 50 as an air-conditioning control device to receive the room temperature-measured values and the room humidity-measured values received by each of the air conditioners 10 so as to control operations of the central heat source device 40 and each of the air conditioners 10.
Each of the air conditioners 10 obtains the measured values from the temperature sensor 20 and humidity sensor 30 concerned and sends the measured values to the air-conditioning linkage controller 50. In addition, each of the air conditioners 10 includes, as illustrated in
The central heat source device 40 includes a refrigerator 41 for generating cold water, a cooling tower 42 for cooling water by air so as to reuse the water heated by cooling of the refrigerator 41, and a water pump 43 for delivering cold water between the refrigerator 41 and each of the air conditioners 10 or the cooling tower 42.
The air-conditioning linkage controller 50 obtains the measured values of the temperature sensors 20 and the humidity sensors 30 sent from each of the air conditioners 10. Then, the air-conditioning linkage controller 50 calculates an optimum room temperature setting value and humidity setting value in each room within a preset range of a comfort index so that a sum of consumption energies in the cooling tower 42, the refrigerator 41 and the water pump 43 of the central heat source device 40 and the outer air cooling coil 11, the return air cooling coil 12 and the blast fan 13 of each air conditioner 10 is to be the minimum value. Further, the air-conditioning linkage controller 50 sends the calculation result to each of the air conditioners 10 and the central heat source device 40.
Operations of the air-conditioning control system 1 according to the first embodiment will be explained with reference to a sequence diagram of
First, air-conditioning control in the building A is started. Next, each of the temperature sensors 20 measures room temperature in each room, and each of the humidity sensors 30 measures room humidity in each room. Then, the measured temperature and humidity values in each room are sent to the air conditioners 10 provided in each room (S1).
The measured values are received in each of the air conditioners 10, and further sent from the air conditioners 10 to the air-conditioning linkage controller 50 (S2).
The air-conditioning linkage controller 50 calculates an optimum room temperature setting value and humidity setting value in each room from the received measured values, within a range in which a PMV (Predicted Mean Vote) level is evaluated as a comfort level so that a sum of consumption energies, as a total necessary consumption energies, in the cooling tower 42, the refrigerator 41 and the water pump 43 of the central heat source device 40 and the outer air cooling coil 11, the return air cooling coil 12 and the blast fan 13 of each of the air conditioners 10 is to be the minimum value.
The PMV used for the calculation of each value will be explained.
The PMV means a comfort index obtained by six variables, (a) an air temperature, (b) a relative humidity, (c) a mean radiation temperature, (d) a speed of airflow, (e) the amount of activity (the amount of internal heat generation from a human body), and (f) a volume of clothing, as variables to affect a sensation of warmth of human with respect to hotness and coldness.
The amount of heat generation from a human body is represented by a sum of the amount of radiation by convection flow, the amount of heat release by radiation, the amount of heat of vaporization from a human body, and the amounts of heat release and heat storage by breathing. When the amount of heat generation is in thermal equilibrium, a human body is thermally neutral. Therefore, a room with such a condition is in a comfortable state for a human body, which is neither hot nor cold. On the other hand, when the amount of heat generation is not in thermal equilibrium, a human body feels hot or cold.
In 1967, Professor Fanger of Technical University of Denmark presented an introduction of a comfort equation. From this point, Professor Fanger statistically started analyzing surveys of a number of test subjects, and connected a heat load of a human body and a human thermal sensitivity, thereby providing the PMV. Since ISO (International Organization for Standardization) employed the PMV in 1994, the PMV has been commonly used in recent years.
The PMV as a thermal index is represented by the following numerical numbers by a seven-grade evaluation scale, as
+3: hot,
+2: warm,
+1: slightly warm,
0: neutral or comfortable,
−1: slightly cool,
−2: cool, and
−3: cold.
Note that, a range of the PMV values in which a human body feels comfortable is between −0.5 to +0.5.
In the above six variables, a unit “met” is used in the amount of activity representing a work intensity, and a unit “clo” is used in the volume of clothing.
The unit “met” represents the amount of metabolism, in which a metabolic value at rest under a thermally comfortable condition is a standard value. Here, 1 met is represented by the following formula (1), as
1 met=58.2 W/m2=50 kcal/m2·h (1)
In addition, the unit “clo” represents heat insulation of clothing. 1 clo represents a value in a clothed state, in which the amount of heat release from a surface of a human body is equivalent to the metabolic value of 1 met in a room at 21° C., 50% relative humidity, and 5 cm/s or less of airflow. When the value is converted to a normal thermal resistance value, 1 clo is represented by the following formula (2), as
1 clo=0.155 m2·° C./W=0.180 m2·h·° C./kcal. (2)
The following formula (3) represents a calculation formula of the PMV value, as
PMV=(0.352e−0.042 M/A+0.032)·L. (3)
Here, M is the amount of activity [kcal/h], A is a human body surface area [m2], and L is a human body heat load [kcal/m2 h] (calculated by the comfort equation of Fanger). Using the formula (3), the target PMV value is set to a PMV value in a hotter direction when cooling, and set to a PMV value in a colder direction when heating, respectively, within a comfortable range (−0.5<PMV<+0.5). As a result, an air-conditioning load is reduced, and energy saving is achieved.
Next, a calculation of an optimum set value of each of the air conditioners 10 will be explained.
As described above, the total consumption energy consumed in the air-conditioning control system 1 is a sum of the respective consumption energies in the cooling tower 42, the refrigerator 41 and the water pump 43 of the central heat source device 40 and the outer air cooling coil 11, the return air cooling coil 12 and the blast fan 13 of each of the air conditioners 10.
In order that the total consumption energy consumed in the air-conditioning control system 1 is to be the minimum value, a method described in the description of JP 2008-232507 A as an algorithm for calculating the set value of each of the air conditioners 10 has been provided. In this method, a state quantity necessary to optimize air conditioning, such as an internal heat generation quantity, an internal water vapor generation quantity, and a physical quantity obtained by e.g. multiplication of an overall heat-transfer coefficient and a heat-transfer area in a heat exchanger, is estimated from measured values of each sensor used in the air-conditioning control. Accordingly, the optimum control can be achieved in view of the overall air-conditioning system. In addition, as another algorithm, a method as described in the description of JP 2008-256258 A has been provided. In this method, a provisional total air-conditioning load is calculated from the amount of heat exchange between a present heat source device and cooling coil in an initial stage. Then, an air-conditioning device in an air-conditioning system is controlled by defining the total air-conditioning load as a variable, based on an optimum operation state quantity of the air-conditioning system. When a condition of air in a space subject to the air-conditioning control approximately corresponds to a set air-conditioning condition, a true total air-conditioning load is calculated, thereby determining the optimum operation state quantity. As a result, air conditioning is operated efficiently, whereby energy saving of the air-conditioning system is achieved.
In the first embodiment, as described above, the optimum set value of each of the air conditioners 10 is calculated within a range between −0.5 and +0.5 in which the PMV value is evaluated as a comfort level so that the total consumption energy of the air-conditioning control system 1 is to be the minimum value. Then, the set values are sent to the air conditioners 10 and the central heat source device 40 (S3).
When the optimum set values of the air conditioners 10 are provided to the central heat source device 40, cold water necessary for the air conditioners 10 is supplied based on the set values (S4). As a result, air controlled in consideration for comfort of people is supplied to each room subject to the air-conditioning control (S5).
Next, an operation of each of the air conditioners 10 when controlled air is supplied to each room subject to the air-conditioning control will be explained.
When a cooling process is performed by the air-conditioning control system, two functions, a function to dehumidify and cool flesh outer air introduced in a building for residents (latent heat cooling load) and a function to cool generated sensible heat from lightings, OA equipments, human bodies, and the like in the building (sensible heat cooling load), are performed by the air conditioners.
When a conventional air conditioner performed cooling, the above two functions were concurrently performed by mixing outer air and return air. However, only outer air is required to be dehumidified in this case. Thus, a required temperature and the flowing amount of cooling water are different in each function. Therefore, it is more effective to perform the two functions individually.
Accordingly, in the first embodiment as illustrated in
According to the above-described first embodiment, comfort of people in a room is considered, outer air and return air are controlled individually, and the total necessary consumption energy in the system is controlled so as to be the minimum value. Thus, it is possible to perform air-conditioning controlling so as to achieve energy saving of consumption energy effectively.
A constitution of an air-conditioning control system 2 according to a second embodiment of the present application is similar to that of the first embodiment as illustrated in
Operations of the air-conditioning control system 2 according to the second embodiment are similar to those according to the first embodiment except for the calculation of the set values of each of the air conditioners 10 in step S3 of
In the second embodiment, a process, in which the air-conditioning linkage controller 50 calculates the set values of each of the air conditioners 10 so that the necessary consumption energy is to be the minimum value within a range in which the PMV level is evaluated as a comfort level in step S3 of
Meanwhile, in order to reduce greenhouse gas, the Japanese government has recommended that a temperature of an air conditioner in summer be set to 28° C.
In this case, when the room temperature is 28° C., the PMV value exceeds +0.5 that is an upper limit of the comfortable range for people no matter how low the humidity is, as illustrated in
However, when the speed of airflow in the room is 0.5 m/s, the PMV value is +0.5 or less (approximately 0.43) at 40% humidity even if the room temperature is 28° C.
Thus, in the second embodiment, the air conditioner 10 is configured to supply wavering air from a blast portion thereof to the room subject to the air-conditioning control so that a maximum speed of airflow is 0.5 m/s adjacent to 1 meter above a floor, which is the same level as the middle portion of the people's height.
Due to such wavering air to be supplied, an average speed of airflow can be set to less than 0.5 m/s. Therefore, it is possible to provide a comfortable air-conditioning operation for people in a room without significantly increasing consumption energy of the blast fan 13 even if a preset room temperature is 28° C.
According to the above-described second embodiment, the optimum set values of the air conditioners 10 are calculated in addition to the consideration of the speed of airflow of air from the air conditioners 10. Thus, it is possible to perform air-conditioning controlling so as to achieve energy saving of consumption energy more efficiently and comfort maintenance.
A constitution of an air-conditioning control system 3 according to a third embodiment of the present application is provided with at least one of a carbon dioxide sensor (not illustrated) and a human body detection sensor (not illustrated) in each room subject to the air-conditioning control. The other constitutions are the same as those of the first embodiment illustrated in
The carbon dioxide sensor measures a level of carbon dioxide in each room discharged from people, followed by sending the measured value to the air conditioners 10. Also, the human body detection sensor detects the number of people in each room subject to the air-conditioning control, followed by sending the detected value to the air conditioners 10.
Operations of the air-conditioning control system 3 according to the third embodiment will be explained with reference to
First, air conditioning control in the building A is started. Next, each of the temperature sensors 20 measures room temperature in each room, and each of the humidity sensors 30 measures room humidity in each room. In addition, the carbon dioxide sensor measures a level of carbon dioxide in each room, or the human body detection sensor detects the number of people in each room. The measured values measured by each sensor are sent to the air conditioners 10 installed in each room (S1).
Each of the air conditioners 10 receive the measured values sent from each sensor, followed by sending the received values to the air-conditioning linkage controller 50 (S2).
In the third embodiment, a process, in which the air-conditioning linkage controller 50 calculates the set values of each of the air conditioners 10 so that the necessary consumption energy is to be the minimum value within a range in which the PMV level is evaluated as a comfort level, will be explained.
In the air-conditioning linkage controller 50 according to the third embodiment, a damper aperture is controlled, so as to supply air to the outer air cooling coil 11, the return air cooling coil 12 and the blast fan 13 according to a graph illustrated in
As illustrated in
When one of the points of the minimum outer air (b), the mid-level outer air (c) and the maximum outer air (d) is selected, each damper aperture is controlled so as to actively introduce outer air when air in each room is required to be cooled, and enthalpy of outer air is lower than enthalpy of inner room and thus it is better to let outer air in energetically. Accordingly, the used amount of cold water to be supplied to the return air cooling coil 12 is reduced.
Moreover, when a load of the outer air cooling coil 11 is larger than a certain level, each damper aperture is controlled according to
Specifically, when the level of carbon dioxide becomes higher than a certain level, or when the number of people in each room reaches a certain number, each damper aperture is controlled to introduce the minimum amount of outer air so as to lower the level of carbon dioxide to less than a certain level, thereby lowering the level of carbon dioxide due to air ventilation. Thus, air ventilation is performed without excessively reducing the load of the outer air cooling coil 11.
As described above, when the set values of each of the air conditioners 10 are determined so that the necessary consumption energy of each device is to be the minimum value, the set values of each of the air conditioners 10 are controlled by the cooling operation by outer air, and the minimum outer air intake based on the level of carbon dioxide or the number of people in each room (S3). Then, based on the set values, the central heat source device 40 supplies necessary cold water to the air conditioners 10 (S4). As a result, controlled air in consideration of comfort for people in each room is supplied to each room subject to the air-conditioning control (S5).
According to the above-described third embodiment, the optimum set values of the air conditioners are calculated in consideration of the cooling operation by outer air, and the outer air intake based on the level of carbon dioxide or the number of people in each room. Therefore, it is possible to perform air-conditioning controlling so as to achieve energy saving of consumption energy more efficiently.
A constitution of an air-conditioning control system 4 according to a fourth embodiment of the present application is provided with two systems of heat source devices, the central heat source device 40 and a second central heat source device 40′. The other constitutions are the same as those of the first embodiment. Thus, the specific explanations of the same portions as the first embodiment will not be repeated.
In the fourth embodiment, the central heat source device 40 supplies cold water to the outer air cooling coils 11, and the second central heat source device 40′ supplies cold water to the return air cooling coils 12.
Operations of the air-conditioning control system 4 according to the fourth embodiment are similar to those according to the first embodiment except for processing of supplying cold water in step S5 of
In step S6 in the fourth embodiment, when cold water is supplied to each of the air conditioners 10, the central heat source device 40 supplies cold water to the outer air cooling coils 11, and the second central heat source device 40′, which is a different system from the central heat source device 40, supplies cold water to the return air cooling coils 12.
In a conventional air-conditioning control system, cold water supplied to a cooling coil from a central heat source device is approximately 7° C. However, such cold water at 7° C. is required only when outer air is dehumidified and cooled. While, cold water may be approximately 13° C., which is enough to cool return air in each room subject to the air-conditioning control. The energy amount necessary to dehumidify and cool outer air (latent heat cooling load) is approximately 30% to 20% of the total energy amount necessary to perform air-conditioning controlling at cooling. Namely, 70% to 80% of the total energy amount is applied to the energy amount necessary to cool return air (sensible heat cooling load), which is used to excessively cool cold water. As a result, consumption energy is unnecessarily wasted.
In view of this, the fourth embodiment is provided with the two cold water supply source systems of the central heat source device 40 for supplying cold water to the outer air cooling coils 11 and the second central heat source device 40′ for supplying cold water to the return air cooling coils 12. In addition, cold water supplied to the outer air cooling coils 11 from the central hat source device 40 is configured to be approximately 7° C. While, cold water supplied to the return air cooling coils 12 from the second central heat source device 40′ is configured to be approximately 13° C.
According to the above-described fourth embodiment, the two systems of the central heat source devices 40 and 40′ are provided. Accordingly, energy consumption unnecessary wasted by adjusting cold water to excessively low temperature can be prevented. Thus, it is possible to perform air-conditioning controlling so as to achieve energy saving of consumption energy more efficiently.
A constitution of an air-conditioning control system 5 according to a fifth embodiment of the present application is similar to that of the air-conditioning control system 1 according to the first embodiment illustrated in
Each air conditioner 10 includes a plurality of valves as illustrated in
Operations of the air-conditioning control system 5 according to the fifth embodiment are similar to those according to the first embodiment except for processing of supplying cold water in step S5 of
In step S5 in the fifth embodiment, when cold water is supplied to each of the air conditioners 10, cold water at 7° C. is first supplied to the outer air cooling coil 11 from the central heat source device 40. Then, cold water used in the outer air cooling coil 11 is reused in the return air cooling coil 12. As described in the fourth embodiment, cold water to be used in the return air cooling coil 12 is not necessarily as cold as that used in the outer air cooling coil 11. Therefore, the return air cooling coil 12 can reuse cold water after being used in the outer air cooling coil 11.
In this case, the amount of cold water supplied to the outer air cooling coil 11 from the central heat source device 40 is controlled by the aperture of the valve 14. In addition, the amount of cold water supplied to the return air cooling coil 12 after being used in the outer air cooling coil 11 is controlled by each aperture of the valve 15 and the valve 16. Moreover, when the amount of cold water used in the outer air cooling coil 11 is not enough for cold water to be used in the return air cooling coil 12, cold water is directly supplied to the return air cooling coil 12 from the central heat source device 40 by opening the valve 17.
According to the above-described fifth embodiment, the outer air cooling coil 11 is connected to the return air cooling coil 12 in series. Due to such a configuration, cold water used in the outer air cooling coil 11 can be reused in the return air cooling coil 12. Thus, it is possible to perform air-conditioning controlling so as to achieve energy saving of consumption energy more efficiently.
In the above first embodiment to fifth embodiment, the case where the central heat source device 40 is installed in the building A subject to the air-conditioning control has been explained. When the air-conditioning control is performed by a DHC (District Heating and Cooling) operation since the refrigerator 41 and the cooling tower 42 of the central heat source device 40 are not installed in the building, cold/hot water may be supplied externally (however, the water pump 43 for supplying cold/hot water to each air conditioner is provided in the building). In such a case, the total consumption energy in the air conditioning control system is a sum of consumption energies of the water pump, the outer air cooling coil, the return air cooling coil, and the blast fan.
In addition, in the above first embodiment to fifth embodiment, the case where each value measured by each sensor is sent to the air-conditioning linkage controller 50 from each sensor via each of the air conditioners 30 has been explained. However, the present application is not limited to this case. Each measured value may be sent to the air-conditioning linkage controller 50 directly from each sensor.
Moreover, in the above first embodiment to fifth embodiment, the PMV value has been used as a comfort index of a sensation of warmth of human. However, the present application is not limited to this case. The air-conditioning control may be performed by using such as a standard effective temperature and a new effective temperature.
Furthermore, each embodiment may be performed in combination as long as it is available. It is possible to obtain much better effects by combining each embodiment.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-016218 | Jan 2008 | JP | national |
This application is a Continuation of U.S. application Ser. No. 12/864,680, that is a 371 National Stage application of International Application No. PCT/JP2009/051164, filed Jan. 26, 2009, which claims the benefit of priority from Japanese Patent Application No. 2008-016218, filed Jan. 18, 2008, the entire contents of all of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12864680 | Jul 2010 | US |
| Child | 15067883 | US |
