This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2011-196984, filed on Sep. 9, 2011, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a predicted mean vote (PMV) estimating device and a computer program product of the PMV estimating device, for estimating a PMV which is a quantitative index for human thermal sensation.
Currently, it has been desired to promote energy saving at consumer's end, such as in buildings or houses. Furthermore, due to an influence of the earthquake disaster and tight power demand and supply, a solution for saving more energy (power saving) has been desired. Thus, it has been increasingly important to promote the energy saving at the consumer's end.
Recently, there is a discussion to introduce a “demand-response,” which suppresses a power consumption at the consumer's end, in a next generation power system (referred to as the Smart Grid). Here, the next generation power system is realized by establishing a communication environment between the power supplier's end and the power consumer's end. It is considered that, in the future, the energy saving at the consumer's end aiming for overall optimization of the power usage, such as adjustment or systematic stabilization of the power demand and supply, becomes more familiar.
In order to realize increasing the energy saving at the consumer's end, it is necessary to correctly understand environment of a room of the consumer. For example, an energy consumption of air conditioning related devices that maintain environment, such as a room temperature and room humidity, takes up approximately one fourth of the energy consumption of the entire office building. Thus, if excess heating or cooling is recognized and optimized, there is a possibility that large energy saving effect is obtained.
There is known an index referred to as a predicted mean vote (PMV), which is employed as a standard thermal comfort index (standard heat index) of the International Organization for Standard (ISO) 7730. The PMV is an index obtained by obtaining an unbalanced heat with respect to the environment, and by associating the unbalanced heat with thermal sensation. Accordingly, there has been proposed a technique to control air conditioning by using the PMV as a control index for the air conditioning, in order to improve comfort and to increase energy saving by removing the excess cooling and the heating.
However, in the conventional technology, there is no consideration on influence of a temperature change in a solar radiated article that directly receives solar radiation. Here, the solar radiated article is, for example a blind for blocking solar radiation from entering into a room via a window. Thus, the PMV estimated by the conventional technique might be different from that of the actual environment. If such PMV is used as the control index for the air conditioning or the like, there is a possibility that a predicted room environment of the air conditioning or an energy saving effect cannot be obtained.
A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
In general, according to one embodiment, a predicted mean vote (PMV) estimating device calculates a PMV value from an average room radiation temperature, a room temperature, a room humidity, a room air velocity, an amount of cloth worn by a person in the room, and an amount of activity of the person in the room. The PMV estimating device comprises: an indoor solar radiation calculator; a solar radiated article temperature estimator; and an average radiation temperature estimator. The indoor solar radiation calculator calculates an amount of solar radiation entered into the room. The solar radiated article temperature estimator estimates a temperature of a solar radiated article receiving the solar radiation entered into the room, by using the amount of solar radiation entered into the room calculated by the indoor solar radiation calculator. The average radiation temperature estimator estimates the average room radiation temperature by using the temperature of the solar radiated article estimated by the solar radiated article temperature estimator.
In order to estimate a PMV, it is necessary to understand total of six factors, which are: an amount of activity and an amount of worn cloth as human factors; and a temperature, a humidity, an average radiation temperature, and an air velocity as environmental factors. The average radiation temperature is a surface temperature of a virtual closed space at a uniform temperature, which exchanges the same amount of heat radiation as the amount of heat radiation exchanged between the person in the room and the surrounding environment. The average radiation temperature is calculated by using a surface temperature of a wall or a sealing around the person in the room. In a first embodiment, the PMV is estimated by a PMV estimating device including the following configurations.
As illustrated in
Detailed operations of each unit are explained with reference to a flowchart of
The indoor solar radiation calculator 10 performs a sequence of operations from S1 to S4 illustrated in
In the above equations, φ represents a latitude [deg.] of where the calculation is taken place, δ represents a declination [deg.] of the sun, and t represents an hour angle [deg.]. The declination δ of the sun is represented as function of day of year (1 for January 1st and 365 for December 31st), and can be calculated from the current month d and the date d. Further, the hour angle t is calculated from the current time ti, an equation of time (which is function of the day of year, and can be calculated from the current month m and the date d), a longitude of where the calculation is taken place, and a standard longitude of the central standard time (regarding the declination of the sun and the hour angle, see for example ““Journal of the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, Title II, Air-Conditioning Facility”, 11th Edition, the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, p. 68”). Then, by using the position of the sun obtained as mentioned above, an incident angle i [deg.] of the sun by following Equation (3). In the following equation, θ represents an inclination angle [deg.] of a calculation surface (window surface) from a horizontal plane, and α represents a wall azimuth angle [deg.].
Next, at S3, an amount Is [kcal/m2·h] of diffuse solar radiation and an amount Id [kcal/m2·h] of direct solar radiation at a plane of calculation are derived by using the aforementioned incident angle i of the sun.
Here, I0 represents a sun multiplier (an amount of outer space direct solar radiation), Isky represents an amount of horizontal diffuse solar radiation, and P represents an atmospheric transmittance. Isky can be calculated by using following Equation (6).
Next, at S4, an amount Igr [kcal/m2·h] of solar radiation in the room is calculated by following Equation (7).
Igr=[Id×CId(i)×τW]+(Is×Cd×τW) (7)
In the above equation, Cid represents a transmittance ratio of a standard glass by incident angles, and is function of the incident angle i of the sun (1 if the incident angle i=0 [deg.]). Further, Cd represents a transmittance ratio of diffuse solar radiation at its vertical incidence, and τW represents a transmittance of the glass with respect to the solar radiation at its vertical incidence. The amount of the solar radiation in the room, which is entered into the room via the window glass, can be calculated by the aforementioned operations.
Next, the solar radiated article temperature estimator 11 performs a sequence of operations from S5 to S7.
At S5, a temperature Tbr [° C.] of the solar radiated article such as a blind or a drape is temporarily determined. Then, at S6, an amount of heat dissipation via convection and an amount of heat dissipation via radiation are calculated. The amount Qf [kcal/m2] of heat dissipation via convection can be calculated by following Equation (8), while assuming heat-transfer by natural convection at vertical plate.
In the aforementioned equation, Nu represents an average Nusselt number, which can be obtained from, for example, the temperature Tbr [° C.] of the solar radiated article (temperature of the heated body), the room temperature T [° C.], and the height Hbr [m] of the solar radiated article (regarding Nusselt number, see for example ““Journal of the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, Title I, Basic”, 11th Edition, the Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, p. 171”. Further, λ represents a heat conductivity [kcal/(m·k)], and it is function of a room temperature T (regarding the heat conductivity, see for example “Heat Transfer”, 3rd Edition, the Japan Society of Mechanical Engineers, p. 300)). On the other hand, the amount Qr [kcal/m2] of heat dissipation by radiation is for example calculated by following equation (9). Here, σ represents Stefan-Boltzmann constant [W/(m2·K4)], and εbr represents radiation ratio (absorption ratio) of the solar radiated article.
From above, at S7, a heat balance equation of the solar radiated article can be formulated as in following Equation (10).
By repeatedly calculating the temperature Tbr [° C.] of the solar radiated article that satisfies the equation (10), the temperature of the solar radiated article, such as the blind or the drape, can be estimated.
The average radiation temperature estimator 12 derives an average radiation temperature Trad [° C.] at a point where the PMV is to be estimated, by using the temperature Tbr of the solar radiated article estimated as described above. The average radiation temperature Trad [° C.] can be calculated by following equation (11), where dΩbr represents a solid angle [sr] of the solar radiated article as viewed from the point where the PMV is to be estimated, dΩ0 represents a solid angle [sr] of each surfaces in the room (wall surface, sealing surface, and the floor surface) other than the solar radiated article as viewed from the point where the PMV is to be estimated, and T0 represents a temperature [° C.] of the each surface in the room (S8).
At last, the PMV arithmetic unit 13 estimates a current PMV by a known PMV mathematical formula or its regression formula, by using the estimated average radiation temperature Trad [° C.], and a measured or set room temperature T [° C.], a measured or set room humidity H [%], a measured or set room air velocity V [m/s], a measured or set amount C [clo] of worn cloth of a person in the room, and a measured or set amount M [met] of the activity (S9).
A PMV estimating device according to a second embodiment is configured so as to be capable of correctly estimating a PMV in accordance with a change in weather, by detecting a momentarily changing amount of solar radiation, by calculating a temperature of the solar radiated article in accordance with the detected amount of the solar radiation, and by estimating the average radiation temperature. In the present embodiment, the estimation of the PMV is performed by the PMV estimating device having the following configurations.
As illustrated in
Next, operations of the PMV estimating device of the present embodiment is explained with reference to a flowchart of
At S3, the amount Id [kcal/m2·h] of direct solar radiation and the amount Is [kcal/m2·h] of diffuse solar radiation are derived by using the incident angle i of the sun (see Equations (4) and (5)). However, the amount of the solar radiation changes largely due to momentarily changing weather. Factors for such change are, blockage of the solar radiation by clouds, and changes in an atmospheric transmittance due to changes in temperature and humidity. Thus, there is introduced an amount CC of clouds, which is a correction coefficient for estimating an amount of solar radiation decreased due to the aforementioned weather. Accordingly, at S3-(2), the cloud amount estimator 15 estimates the amount of clouds which differs by weather condition. Here, the amount CC of clouds is assumed to be a dimensionless quantity of an arbitrarily value between 0 to 10. An amount Idc [kcal/m2·h] of direct solar radiation and an amount Isc [kcal/m2·h] of diffuse solar radiation, which take into account the aforementioned weather condition, are expressed by following Equations (12) and (13).
As the solar radiation detecting device 14, a solar radiation sensor horizontally placed at a rooftop is assumed. θ=0 [deg.] and the incident angle i [deg.] of the sun thereof, obtained by Equation (3), are substituted into Equations (12) and (13). Then, the amount of clouds can be estimated by deriving a value of CC satisfying, for example, following Equation (14).
In equations (12) and (13), coef_CC is a parameter of a degree of influence of the amount of clouds, and can be set to an arbitrarily value in accordance with conditions. By using the amount CC of clouds estimated as mentioned above, the amount Idc [kcal/m2·h] of direct solar radiation and the amount Isc [kcal/m2·h] of diffuse solar radiation at each window surface where the solar radiated article is placed are obtained by Equations (12) and (13) at S3(3), while taking into account the weather condition. The subsequent operations are the same as that of the operation flow of the first embodiment as illustrated in
According to the above described PMV estimating device of the present embodiment, it becomes possible to estimate the temperature of the solar radiated article, such as a blind or a drape, while taking into account the change in the amount of the solar radiation due to the weather condition. Further, by evaluating the average radiation temperature using the estimated temperature, it becomes possible to correctly estimate the PMV corresponding to the momentarily changing solar radiation environment.
In comparison to the above second embodiment, a PMV estimating device of a third embodiment uses a solar power generator as the solar radiation detecting device.
In a PMV estimating device 3 of the present embodiment, the cloud amount estimator 15 is configured to preliminarily hold a relational expression or a correspondence table between an amount of clouds and a ratio of power generation of a solar power generator 16, as illustrated in
Operations of the PMV estimating device 3 of the present embodiment are same as that of the PMV estimating device 2 of the aforementioned second embodiment, except that the amount of clouds is estimated based on the relational expression or the correspondence table between the amount of clouds and the ratio of power generation (ratio with respect to the maximum amount of generated electricity on sunny day by each season) of the solar power generator 16.
According to the PMV estimating device of the present embodiment, by utilizing the solar power generator 16, which has recently been widely introduced, as the solar radiation detecting device, it becomes unnecessary to install an additional equipment for detecting the amount of solar radiation. Accordingly, cost can be reduced as well as effort for the maintenance and the management can be saved.
A PMV estimating device of a fourth embodiment is configured so as to be able to correctly estimate a PMV at an arbitrary point in the room while taking into account the influence of changes in temperature of the solar radiated article by the window, by introducing an average radiation temperature using a solid angle corresponding to a relative positional relationship between the point where the PMV is to be estimated and the window or the wall. In the present embodiment, the PMV is estimated by a PMV estimating device having the following configurations.
The PMV estimating device 4 of the present embodiment additionally comprise an atmospheric radiation temperature estimator 17. The atmospheric radiation temperature estimator 17 estimates an atmospheric radiation temperature from an amount of solar radiation in the room due to the diffuse solar radiation, from among the amount of solar radiation calculated by the indoor solar radiation calculator 10. Accordingly, the PMV estimating device 4 estimates a practical average radiation temperature, even in a case when the window side of a blind, a drape, and/or the like are not entirely covered by the solar radiated article. In order to construct the present embodiment, it is assumed that there is no direct solar radiation from an opening at the window side. This is because it is often the case that, if there exists direct solar radiation, a person in the room normally blocks the direct solar radiation by moving the solar radiated article, such as a blind or a drape, and adjusting a degree of opening of the window.
Operations of the PMV estimating device of the present embodiment is explained with reference to the flowchart of
At S4, the indoor solar radiation calculator 10 derives the amount I′gr [kcal/m2·h] of solar radiation in the room due to diffuse solar radiation by following Equation (15).
I′gr=Is×Cd×τW (15)
Here, Is represents an amount [kcal/m2·h] of diffuse solar radiation, and calculated by Equation (15). Further, Cd represents a transmittance ratio with respect to diffuse solar radiation when its incident angle is vertical, and τW represents a transmittance of a glass at the time of vertical incidence.
Next, at S10, the atmospheric radiation temperature estimator 17 estimates an atmospheric radiation temperature Tair [° C.] by using the amount I′gr of the solar radiation in the room due to the aforementioned diffuse solar radiation. This is estimated by using a relational expression or a correspondence table between an amount of solar radiation in the room due to the diffuse solar radiation preliminarily measured at, for example, a building surface facing the North where there is not direct solar radiation and an atmospheric radiation temperature at this measurement.
Then, at S8, an average radiation temperature Trad [° C.] at the point where the PMV is to be estimated is derived by following Equation (16), by using the atmospheric radiation temperature Tair obtained as mentioned above.
Here, dΩbr represents a solid angle [sr] of the solar radiated angle as viewed from the point where the PMV is to be estimated; dΩ′br represents a solid angle [sr] of an opening of the solar radiated article as viewed from the point where the PMV is to be estimated; dΩ0 represents a solid angle [sr] of each surface in the room other than the solar radiated article, as viewed from the point where the PMV is to be estimated; Tbr represents a temperature of the solar radiated article; and T0 represents a temperature [° C.] of each surface in the room other than the solar radiated article.
dΩ′br is calculated by following Equation (17) by using a coefficient α (e.g., 0 when fully closed and 1 when fully opened), which represents a degree of opening of the solar radiated article such as a blind or a drape, with respect to the solid angle dΩbr of the solar radiated article as viewed from the point where the PMV is to be estimated.
dΩ′br=dΩbr×α (17)
Other operations are the same as that of the operation flow of the second embodiment illustrated in
According to the PMV estimating device of the present embodiment described above, even if the solar radiated article such as a blind or a drape is not fully closed, an average radiation temperature and a PMV that match the actual practice can be estimated. In the above, additional functions, operations, and effects specific to the present embodiment are explained over the configuration of the second embodiment; however, the additional functions specific to the present embodiment may be applied to the aforementioned first embodiment or the third embodiment.
A PMV estimating device of a fifth embodiment is configured so as to be able to correctly estimate a PMV at an arbitrary point in the room while taking into account heat transfer with respect to an outside air via a window and transfer of radiation energy between inside and outside of the room except for that of the solar radiation. In the present embodiment, the PMV is estimated by a PMV estimating device having the following configurations.
In comparison to the PMV estimating device 2 of the second embodiment, PMV estimating device 5 of the present embodiment is further provided with an outside-air-based temperature change estimator that estimates change in temperature of a solar radiated article such as a blind or a drape due to the influence of the heat transfer with respect to the outside air via the window or the transfer of the radiation energy between inside and outside the room except for that of the solar radiation.
Next, operations of the PMV estimating device of the present embodiment are explained with reference to the flowchart of
In the present embodiment, at S4-(2), it is determined whether there exists solar radiation. If it is determined that there exists solar radiation (Yes at S4-(2)), the process moves to S5 and the subsequent steps. If it is determined that there exists no solar radiation (No at S4-(2)), the temperature Tbr of the solar radiated article is calculated, at S4-(3), similarly as described above, and the process moves to S8.
At S6-(2), the outside-air-based temperature change estimator 18 estimates change in temperature ΔTbr [° C.] of the solar radiated article such as the blind or the drape due to the influence of the heat transfer with respect to the outside air via the window or the transfer of the radiation energy between inside and outside the room.
The change in temperature ΔTbr [° C.] of the solar radiated article is estimated by a relational expression based on an outside air temperature, a room temperature, and a temperature of the solar radiated article, measured during the night when there exists no solar radiation. That is to say, it is derived how much the temperature of the solar radiated article change from the room temperature, in accordance with the difference between the outside air temperature and the room temperature, by for example following relational Equation (18).
ΔTbr=K·(Tout−T) (18)
In the aforementioned equation, K represents a proportional constant, and set based on the outside air temperature, the room temperature, and the temperature of the solar radiated article measured at night when there exists no solar radiation.
Next, at S7, the temperature Tbr [° C.] of the solar radiated article such as the blind or the drape is estimated by using the aforementioned change in temperature ΔTbr of the solar radiated article. The method for estimating the temperature of the solar radiated article changes depends of whether the solar radiation exists. If there exists solar radiation, the temperature ΔTbr [° C.] of the solar radiated article is estimated so that a heat balance equation of the solar radiated article illustrated in following Equation (19) is satisfied.
Here, Cbr represents a specific heat of the solar radiated article, such as a blind or a drape. On the other hand, if there exists no solar radiation, the temperature ΔTbr [° C.] of the solar radiated article is calculated by following equation (20).
Tbr=T+ΔTbr (20)
Other operations are the same as that of the operation flow of the second embodiment as illustrated in
As described above, the PMV estimating device of the present embodiments estimate the temperature of the solar radiated article, such as a blind or a drape, by taking into account the influence of the heat transfer with respect to the outside air via a window or the transfer of the radiation energy between inside and outside of the room except for that of the solar radiation. Thus, it becomes capable to estimate a practical temperature of the solar radiated article and a practical average radiation temperature, especially in the night time or in winter when there is a large temperature difference between indoor and outdoor. Therefore, it becomes possible to correctly estimate a practical PMV. Here, the additional functions, their operations and effects specific to the present embodiment are explained with respect to the configurations of the second embodiment. However, the additional functions specific to the present embodiment may be applied to the aforementioned first embodiment, the third embodiment, or the fourth embodiment.
As mentioned above, various embodiments are described. As described above, the PMV estimating device according to the first to the fifth embodiment can correctly estimate a practical PMV. The PMV estimating device of the aforementioned embodiments can be applied to an air conditioning control devices or the like for controlling the air conditioning of the buildings based on the PMV value.
The aforementioned processing program may be stored in a computer readable recording medium, such as a compact disk read only memory (CD-ROM), a floppy disk (FD), and/or a digital versatile disk (DVD), as a installable or executable file, and provided. Further, the aforementioned processing program may be stored on a computer connected to a network such as the Internet, and provided by being downloaded via the network.
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 methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems 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.
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