Air age measuring method and air age measuring system

Abstract

To provide an air age measuring method capable of measuring, in a ventilated room, an indoor air age while continuing ventilation operation without requiring temporary suspension of ventilation operation.SOLUTION: An air age measuring method has an air ventilation step for ventilating air in a room 11; a tracer diffusion step for diffusing tracer fine particles in the room 11 in the state of ventilating the room 11; a tracer concentration determination step for measuring concentration of tracer fine particles in the room 11 in which the tracer fine particles are diffused and determining whether concentration distribution of the fine particles in the room 11 is in a stationary state; a tracer measurement step for measuring numerical data of the tracer fine particles diffused in the room 11 while suspending diffusion of the tracer fine particles and continuing ventilation of the room 11 when it is determined that the concentration distribution of the tracer fine particles in the room 11 is in the stationary state; and an air age calculation step for calculating an air age in the room 11 on the basis of an attenuation state of the tracer fine particles in the room 11 due to a lapse of time from the suspension of diffusion of the tracer fine particles.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and system for measuring the age of air by utilizing a tracer. [Background technology]

[0002] The system disclosed has an age-of-air distribution property analysis system, which includes an analysis space calculation unit that performs analysis and calculation of flow and temperature fields in an analysis space using a turbulent flow model of a mean flow in which turbulence is modeled from the equation of continuity of a fluid, the Navier-Stokes equations which satisfy the laws of conservation of mass and conservation of momentum of a fluid, and the law of conservation of energy based on Fourier's law, and stores the calculated data of the flow field and temperature field in a storage unit; an outlet contribution calculation unit that fixes the flow field and the temperature field and obtains a spatial distribution of the outlet contribution rate which indicates the ratio of air inflow to a measurement point for each outlet; a concentration field calculation unit that generates a tracer uniformly in a room space and solves a diffusion equation for each effective volume distribution corresponding to each outlet, with each outlet contribution rate being the effective volume for that field; and an age-of-air calculation unit that calculates the spatial distribution of the age of air of the air flowing in from each outlet by dividing the concentration field by the corresponding outlet contribution rate (see Patent Document 1). This air age distribution property analysis system can evaluate the age of air corresponding to each outlet and inlet in a room with multiple outlets and inlets, corresponding to the contribution rate of air inflow and outflow from each outlet and inlet, making it possible to design an efficient ventilation system.

[0003] When the mean age of air is short, the air in the space is replaced quickly, and the ventilation of the space is evaluated as good. Conversely, when the mean age of air is long, the air flow is stagnant and the air becomes stagnant, and the ventilation of the space is evaluated as poor (bad). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-101058 A Summary of the Invention [Problem to be solved by the invention]

[0005] When measuring the age of air in a space using such an existing method (step-up method), a process of diffusing a tracer into the room, a process of measuring the concentration of the tracer diffused into the room by the tracer diffusion process, and a process of calculating the age of air from the decay over time of the tracer concentration in the room measured by the concentration measurement process are carried out. Note that under the indoor air conditioning control of the air conditioning control unit, a ventilation operation is performed in which conditioned air produced by an air conditioner is supplied into the room by an intake fan, and the conditioned air that has circulated inside the room is exhausted to the outside by an exhaust fan.

[0006] In the diffusion process of the tracer in the ventilation system room, the air conditioning control unit of the room stops the intake fan, exhaust fan, and air conditioner, and stops the ventilation of the room, and then the tracer generator is started and the tracer generator diffuses the tracer into the room. After the concentration of the tracer diffused into the room reaches the set concentration, the air conditioning control unit operates the intake fan, exhaust fan, and air conditioner to resume ventilation operation, and while performing ventilation operation, the concentration of the tracer in the room is continuously measured by the concentration measurement process, and the age of air in the room is calculated based on the attenuation of the concentration of the tracer in the room over time. In this case, the ventilation operation of the room must be stopped in order to diffuse the tracer into the room at the specified concentration, and the age of air in the room cannot be calculated while the ventilation operation is continued.

[0007] An object of the present invention is to provide an age of air measuring method and an age of air measuring system that can measure the age of air in a space while continuing ventilation operation in a ventilation system space, without the need to temporarily suspend the ventilation operation. [Means for solving the problem]

[0008] The first premise of the present invention for solving the above problems is a method for measuring the age of air in a specified space by utilizing a tracer.

[0009] A first feature of the present invention in the first premise is that the age of air measuring method comprises an air ventilation step of ventilating the air in a space, a tracer diffusion step of diffusing a tracer into the space while the space is ventilated by the air ventilation step, a tracer concentration determination step of measuring the concentration of the tracer in the space into which the tracer has been diffused by the tracer diffusion step and determining whether the concentration distribution of the tracer in the space is in a steady state or not, a tracer measurement step of measuring numerical data of the tracer diffused in the space while stopping the diffusion of the tracer in the tracer diffusion step and continuing ventilation of the space by the air ventilation step if it is determined by the tracer concentration determination step that the concentration distribution of the tracer in the space is in a steady state, and an air age calculation step of calculating the age of air in the space based on the attenuation of the tracer over time in the space after measurement of the numerical data of the tracer is started by the tracer measurement step.

[0010] As an example of the present invention having the first feature, a method for measuring the age of air includes adjusting an amount of tracer generated in a tracer diffusion step, and generating the tracer in the space by the tracer diffusion step until the concentration distribution of the tracer in the space reaches a steady state.

[0011] In another example of the present invention having the first characteristic, the tracer concentration determining step determines whether the concentration distribution of the tracer in the space is in a steady state at a plurality of determination points at positions spaced apart by a predetermined distance.

[0012] In another example of the present invention having the first characteristic, the tracer diffusion step diffuses the tracer into the space from a plurality of tracer generation points at positions spaced apart by a predetermined dimension.

[0013] In another example of the present invention having the first characteristic, the tracer is a tracer particle that diffuses in association with the diffusion of a minute liquid, the tracer diffusion step diffuses a minute liquid containing the tracer particle into the space while continuing ventilation by the air ventilation step, the tracer measurement step measures numerical data of the tracer particle for a predetermined measurement time after the diffusion of the tracer particle by the tracer diffusion step is stopped while continuing ventilation by the air ventilation step, and the age of air calculation step calculates the age of air in the space from the attenuation of the numerical data of the tracer particle over time in the space.

[0014] As another example of the present invention having the first characteristic, the measurement time from stopping the diffusion of the tracer particles in the tracer diffusion process while continuing ventilation in the air ventilation process to measuring the numerical data of the tracer particles in the tracer measurement process is the time from the decay of the numerical data of the tracer particles to the time when the numerical data becomes 0.

[0015] As another example of the present invention having the first characteristic, in the tracer diffusion process, an ultrasonic humidifier is used that generates ultrasonic waves using an ultrasonic vibrator to create minute liquid particles containing tracer microparticles and diffuses the minute liquid particles into space.

[0016] As another example of the present invention having the first characteristic, the tracer measurement process uses a particle counter that uses a light scattering method to measure the number data of tracer particles suspended in space and has a measurement range that includes the particle size of the tracer particles diffused in the space by the tracer diffusion process, or a PM2.5 measurement device that has a measurement range that includes the particle size of the tracer particles diffused in the space by the tracer diffusion process and measures fine particulate matter suspended in space.

[0017] A second premise of the present invention for solving the above problems is an age of air measurement system that measures the age of air in a specified space by utilizing a tracer.

[0018] A second feature of the present invention in the second premise is that the age of air measurement system comprises air ventilation means for ventilating the air of a space, tracer diffusion means for diffusing a tracer into the space, tracer concentration determination means for determining whether the concentration distribution of the tracer in the space is steady state, tracer measurement means for measuring numerical data of the tracer diffusing in the space during a predetermined measurement time, and age of air calculation means for calculating the age of air in the space based on the measured numerical data of the tracer, and in the age of air measurement system, the tracer is diffused into the space by the tracer diffusion means while the air of the space is ventilated by the air ventilation means, and when the tracer concentration determination means determines that the concentration distribution of the tracer in the space is steady state, diffusion of the tracer by the tracer diffusion means is stopped and ventilation of the space by the air ventilation step is continued, while the numerical data of the tracer diffused into the space is measured by the tracer measurement means, and the age of air calculation means calculates the age of air in the space from the attenuation of the tracer in the space over time.

[0019] As an example of the present invention having the second feature, the age of air measurement system adjusts the amount of tracer generated in the tracer diffusion means, and generates the tracer in the space by the tracer diffusion means until the concentration distribution of the tracer in the space reaches a steady state.

[0020] In another example of the present invention having the second feature, the tracer concentration determining means determines whether the concentration distribution of the tracer in the space is in a steady state at a plurality of determination points at positions spaced apart by a predetermined distance.

[0021] In another example of the present invention having the second feature, the tracer diffusing means diffuses the tracer into the space from a plurality of tracer generation points at positions spaced apart by a predetermined dimension.

[0022] In another example of the present invention having the second feature, the tracer is a tracer particle that diffuses in association with the diffusion of a minute liquid, the tracer diffusing means diffuses a minute liquid containing the tracer particle into the space while continuing ventilation by the air ventilation process, the tracer measuring means measures numerical data of the tracer particle for a predetermined measurement time after the diffusion of the tracer particle by the tracer diffusing means is stopped while continuing ventilation by the air ventilation means, and the age of air calculation means calculates the age of air in the space from the attenuation of the numerical data of the tracer particle over time in the space.

[0023] As another example of the present invention having the second feature, the measurement time from stopping the diffusion of the tracer particles by the tracer diffusion means process while continuing ventilation by the air ventilation means to measuring the numerical data of the tracer particles by the tracer measurement means is the time from the decay of the numerical data of the tracer particles to the time when the numerical data becomes 0.

[0024] As another example of the present invention having the second characteristic, the tracer diffusion means uses an ultrasonic humidifier that generates ultrasonic waves using an ultrasonic vibrator to create the minute liquid containing tracer particles and diffuses the minute liquid into space.

[0025] As another example of the present invention having the second feature, the tracer measurement means uses a particle counter that measures number data of tracer particles suspended in space using a light scattering method and has a measurement range that includes the particle size of the tracer particles diffused in the space by the tracer diffusion means, or a PM2.5 measurement device that measures fine particulate matter suspended in space and has a measurement range that includes the particle size of the tracer particles diffused in the space by the tracer diffusion means. Effect of the Invention

[0026] According to the age of air measuring method and age of air measuring system of the present invention, a tracer is diffused in a space while the space is ventilated, the concentration of the tracer in the space into which the tracer has been diffused is measured, and it is determined whether the concentration distribution of the tracer in the space is in a steady state. If it is determined that the concentration distribution of the tracer in the space is in a steady state, the diffusion of the tracer is stopped and ventilation of the space is continued while measuring numerical data of the tracer diffused in the space, and the age of air of the space is calculated based on the attenuation of the tracer over time in the space since the diffusion of the tracer was stopped, so there is no need to temporarily suspend the ventilation operation of the space when the tracer is diffused in the space of the ventilation system, and the age of air in the space can be measured while the ventilation operation is continued. The age of air measuring method and age of air measuring system do not require starting and stopping the ventilation operation at a predetermined timing, and can measure the age of air in the space without the trouble of starting and stopping the ventilation operation. The age of air measuring method and age of air measuring system measure numerical data of the tracer for a predetermined measurement time after diffusion of the tracer is stopped, and calculate the age of air in the space from the attenuation of the numerical data of the tracer over time, so that the age of air in the space can be measured with high accuracy by using the tracer.

[0027] The age of air measuring method and age of air measuring system, which adjust the amount of tracer generated in a space and generate a tracer in the space until the concentration distribution of the tracer in the space reaches a steady state, can reliably bring the concentration distribution of the tracer in the space to a steady state by adjusting the amount of tracer generated in the space. Since the age of air measuring system and age of air measuring system can bring the concentration distribution of the tracer in the space to a steady state by adjusting the amount of tracer generated, there is no need to temporarily suspend ventilation operation of the space in order to bring the concentration distribution of the tracer in the space to a steady state, and the age of air in the space can be measured while continuing ventilation operation.

[0028] The age-of-air measurement method and age-of-air measurement system for determining whether the concentration distribution of a tracer in a space is in a steady state at a plurality of determination points spaced a predetermined distance apart in the space can accurately measure the concentration distribution of the tracer throughout the space by determining whether the concentration distribution of the tracer is in a steady state at any of a plurality of determination points in the space, and can accurately determine the steady state of the concentration distribution of the tracer in the space.

[0029] The age of air measuring method and age of air measuring system in which a tracer is diffused into a space from a plurality of tracer generation points located at positions spaced a predetermined distance apart in the space can rapidly diffuse the tracer throughout the entire space by diffusing the tracer from a plurality of tracer generation points in the space, and can bring the concentration distribution of the tracer in the space into a steady state while continuing ventilation operation.

[0030] The age of air measuring method and age of air measuring system, in which the tracer is a tracer particle that diffuses with the diffusion of a minute liquid, a minute liquid containing the tracer particle is diffused into a space while continuing ventilation, numerical data of the tracer particle is measured for a predetermined measurement time after the diffusion of the tracer particle is stopped while continuing ventilation, and the age of air in the space is calculated from the attenuation of the numerical data of the tracer particle over time in the space, use the tracer particle that diffuses with the diffusion of a minute liquid as the tracer, so that the age of air in the space can be measured reliably and easily, and the age of air in the space can be measured accurately by using the tracer particle. The age of air measuring method and age of air measuring system use the tracer particle that diffuses with the diffusion of a minute liquid as the tracer, so that the calculation of the age of air in the space is not complicated, and the age of air in the space can be calculated easily.

[0031] The age of air measurement method and age of air measurement system in which the measurement time for measuring the numerical data of the tracer particles after stopping the diffusion of the tracer particles while continuing ventilation is the time from when the numerical data of the tracer particles decays to when the numerical data becomes 0, by setting the measurement time for measuring the numerical data of the tracer particles to the time from when the numerical data of the tracer particles decays to when the numerical data becomes 0, can accurately capture the decay in the concentration of tracer particles and accurately measure the age of air in a space.

[0032] The age of air measuring method and age of air measuring system using an ultrasonic humidifier that generates ultrasonic waves by an ultrasonic vibrator to create minute liquids containing tracer particles and diffuses the minute liquids into a space generates minute liquids containing tracer particles by vibration energy of ultrasonic waves, and therefore can reliably and easily measure the age of air in a space using tracer particles at room temperature without using a special heat source. The age of air measuring system and age of air measuring system diffuse minute liquids containing tracer particles into a space by an ultrasonic humidifier while continuing ventilation, measure numerical data of the tracer particles for a predetermined measurement time after the diffusion is stopped after the minute liquid containing tracer particles is diffused into the space, and calculate the age of air in the space from the attenuation of the numerical data of the tracer particles over time in the space, and can therefore quickly measure the age of air in the space.

[0033] The age of air measurement method and age of air measurement system use a particle counter that measures the number data of tracer particles suspended in space by a light scattering method and has a measurement range including the particle diameter of the tracer particles in the diffused space, or a PM2.5 measurement instrument that measures fine particulate matter suspended in space and has a measurement range including the particle diameter of the tracer particles in the diffused space, and measures the numerical data of the tracer particles in space using a particle counter that uses a light scattering method during a predetermined measurement time after the diffusion of a minute liquid containing tracer particles is stopped, so that the numerical data of the tracer particles can be accurately measured by the particle counter and the accurate age of air in the space can be measured. The age of air measurement method and age of air measurement system use a PM2.5 measurement instrument that has a narrower measurement range than a particle counter but accurately captures tracer particles of the same size as PM2.5 and has a relatively simple configuration, so that the numerical data of the tracer particles can be accurately measured by the PM2.5 measurement instrument and the accurate age of air in the space can be measured. [Brief description of the drawings]

[0034] [Figure 1] FIG. 2 is a top view showing an example of an age of air measurement system in a ventilation system room. [Diagram 2] FIG. 11 is a diagram for explaining an example of a procedure for calculating the age of air in a room with a ventilation system. [Diagram 3] FIG. 3 is a diagram for explaining the procedure for calculating the age of air, continuing from FIG. 2. [Figure 4] FIG. 4 is a diagram for explaining the procedure for calculating the age of air, continuing from FIG. 3. [Diagram 5] FIG. 5 is a diagram for explaining the procedure for calculating the age of air, continuing from FIG. 4. [Figure 6] FIG. 2 is a diagram for explaining the concentration decay method, which is a method for measuring the age of air. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The age of air measuring method and age of air measuring system 10 according to the present invention will be described in detail below with reference to the accompanying drawings. Fig. 1 is a top view showing an example of the age of air measuring system 10 in a room 11 (space) of a ventilation system. In Fig. 1, a square indicates an ultrasonic humidifier 15, and a circle indicates a light scattering type airborne particle counter 16 or a PM2.5 measuring instrument 17.

[0036] The age of air measuring method (age of air measuring system 10) utilizes a tracer to measure the age of air in a specified room 11 (space). The age of air measuring method (age of air measuring system 10) uses tracer microparticles as the tracer, which diffuse with the diffusion of minute liquid 12 (liquid droplets).

[0037] The air age measuring method (air age measuring system 10) in the room 11 of Figure 1 includes an air ventilation process (air ventilation means), a tracer diffusion process (tracer diffusion means), a tracer concentration determination process (tracer concentration determination means), a tracer measurement process (tracer measurement means), and an air age measurement process (air age measurement means).

[0038] The air ventilation process (air ventilation means) ventilates the air in room 11 (space). Room 11 (an actual room in which the age of air is measured) shown in Fig. 1 is a room 11 of a ventilation system in which air (outside air) conditioned by an air conditioner (not shown) is supplied to the inside of room 11 by air supply duct 13, and the air inside room 11 is exhausted to the outside of room 11 by exhaust duct 14. Although not shown, an air supply fan (air supply means) is installed in air supply duct 13, and an exhaust fan (exhaust means) is installed in exhaust duct 14.

[0039] In room 11, ventilation operation is performed. In ventilation operation, air (conditioned by an air conditioner) that has passed through supply duct 13 by the supply fan is supplied to room 11, and the air that has passed through room 11 is passed through exhaust duct 14 by the exhaust fan, after which the air in room 11 is exhausted to the outside. The supply fan, exhaust fan, and air conditioner are connected to a control unit (not shown), forming an air conditioning control system. The start / stop and output of the supply fan, exhaust fan, and air conditioner are controlled by the control unit. In this embodiment, a first type ventilation configuration is described, but the configurations of second and third types of ventilation are also applicable.

[0040] The tracer diffusion process (tracer diffusion means) diffuses minute liquid 12 containing tracer particles into a chamber 11 (space) of a specified volume. The tracer diffusion process (tracer diffusion means) uses an ultrasonic humidifier 15. The ultrasonic humidifier 15 generates ultrasonic waves (vibrations) using an ultrasonic vibrator installed at the bottom of a tank, and the vibrations bounce off the surface of the water contained in the tank to create minute liquid droplets (mist), and the minute liquid 12 is diffused into the air (inside the chamber 11) using the physical phenomenon of concentration diffusion.

[0041] As the tracer diffusion process (tracer diffusion means), in addition to an ultrasonic humidifier 15 that generates minute liquid 12 containing tracer particles in the room temperature range without using a special heat source, it is also possible to use a steam (heated) humidifier that heats and evaporates water using a heater and then diffuses the water vapor into the air (inside chamber 11), a hybrid humidifier that combines the steam and ultrasonic types, a heated evaporative humidifier that passes warm air created by a heater and fan through a filter containing water to evaporate the water and diffuse the water vapor into the air (inside chamber 11), and an evaporative humidifier that passes wind created by a fan through a filter containing water to evaporate the water and diffuse the water vapor into the air (inside chamber 11).

[0042] In FIG. 1, multiple ultrasonic humidifiers 15 are installed inside room 11 (an actual room in which the age of air is measured). The ultrasonic humidifiers 15 are installed inside room 11 at locations on the upwind side of room 11 and at locations where the age of air is expected to deteriorate. Although multiple ultrasonic humidifiers 15 are installed in room 11 in FIG. 1, there is no particular limitation on the number or locations of ultrasonic humidifiers 15 installed in room 11, and the number and locations are determined depending on the volume of room 11, the layout of room 11, etc. Also, only one ultrasonic humidifier 15 may be installed inside room 11.

[0043] For example, a humidifier identification number (humidifier identifier) ​​is set for each ultrasonic humidifier 15, and the humidifier identification number is stored in a hard disk of a computer described later. The humidifier identification number (humidifier identifier) ​​may be an individual identification number or model number of each ultrasonic humidifier 15, or the computer may generate a unique identifier for each ultrasonic humidifier 15, and the generated identifier may be used as the humidifier identification number.

[0044] The liquid used in the ultrasonic humidifier 15, steam humidifier, hybrid humidifier, and evaporative humidifier is tap water, which has affinity with humans (PAO, which is used for testing HEPA filters, or saline solution may be used in some cases). The age of air measurement method (age of air measurement system 10) uses the ultrasonic humidifier 15 or other humidifiers as a tracer diffusion step (tracer diffusion means), and the humidifiers can be installed inside the room 11, and the minute liquid 12 can be easily diffused throughout the interior of the room 11 using the humidifier, and the tracer fine particles can be easily diffused throughout the interior of the room 11 as the minute liquid 12 diffuses. The age of air measurement method (age of air measurement system 10) uses tap water as the water used in the humidifier, so there is no need to prepare a special aqueous solution, and tap water can be simply supplied to the humidifier from a water pipe, which allows the age of air measurement system 10 to be simplified and reduced in cost.

[0045] The tracer concentration determination process (tracer concentration determination means) determines whether the concentration distribution of tracer particles (tracer) in the room 11 (space) is in a steady state (a saturated state in which the tracer particles cannot diffuse any further into the room 11). The tracer concentration determination process (tracer concentration determination means) uses a light scattering type airborne particle counter 16 (particle measuring device) or a PM2.5 automatic measurement device 17, which will be described later, and a computer.

[0046] When the computer determines that the change in the measured number data (measurement numerical data) of tracer particles measured by the light scattering type airborne particle counter 16 over time has become sufficiently close to zero, it determines that the concentration distribution of tracer particles in the room 11 (space) is at a steady state.

[0047] In addition, when the computer determines that the change in the measured concentration data (measured numerical data) of the tracer particles measured by the PM2.5 automatic measurement device 17 over time has become sufficiently close to zero, it determines that the concentration distribution of the tracer particles in the room 11 (space) is in a steady state.

[0048] The tracer measurement process (tracer measurement means) measures numerical data (number data or concentration data) of tracer particles diffused in the room 11 (space). The tracer measurement process (tracer measurement means) uses a light scattering type airborne particle counter 16 (particle measuring device) having a measurement range that includes the particle size of the tracer particles diffused in the room 11 (space) by the ultrasonic humidifier 15 (or other humidifier) ​​(diffusion means). Also, the tracer measurement process (tracer measurement means) uses a PM2.5 measuring device 17 having a measurement range that includes the particle size of the tracer particles diffused in the room 11 (space) by the ultrasonic humidifier 15 (or other humidifier) ​​(diffusion means).

[0049] In the tracer measurement process (tracer measurement means), minute liquid 12 containing tracer microparticles is diffused into the interior (space) of chamber 11 by a tracer diffusion process (tracer diffusion means), and when the tracer concentration determination process (tracer concentration determination means) determines that the concentration distribution of the tracer microparticles in chamber 11 (space) is in a steady state, numerical data (number data or concentration data) of the tracer microparticles is measured within a specified measurement time after stopping the ultrasonic humidifier 15 (tracer diffusion process (tracer diffusion means)).

[0050] The light scattering type airborne particle counter 16 takes in air from the chamber 11 through an inlet nozzle and irradiates the air with laser light. When the laser light hits tracer particles contained in the air of the chamber 11 (floating in space), the light is scattered. This scattered light is detected by a photodiode and converted into an electrical signal to measure the number of tracer particles (number data). The size of the particles can be calculated from the voltage, and the number of tracer particles in the air of the chamber 11 (number / m 3 ) can be measured.

[0051] In the tracer measurement process (tracer measurement means), in addition to the light scattering type airborne particle counter 16, a light blocking type particle counter can be used. A light blocking type particle counter places a light source opposite a light receiving element and converts light into an electrical signal. When the light passes through tracer particles contained in the air of the chamber 11 (floating in space), the light received by the light receiving element becomes weaker. The amount of attenuation of the electrical signal is the particle size of the tracer particles, and the number of times the light is blocked is the number data of the tracer particles (particles / m 3 )

[0052] The PM2.5 automatic measuring device 17 is used as the PM2.5 measuring instrument 17. The PM2.5 automatic measuring device 17 is a light scattering type like the particle counter 16, but is relatively inexpensive and has a simple and narrow measurement range. The PM2.5 automatic measuring device 17 employs a light scattering method in which particles sucked in by a pump are classified using an impactor, and then the weight concentration is calculated using the intensity of light scattering when the classified particles are irradiated with light. As a combination method, the weight concentration of PM2.5 is calculated by the b-ray absorption method, in which the classified particles are collected on a paper, and the collected particles are exposed to b-rays and the weight concentration is calculated from the amount of b-rays transmitted.

[0053] In the impactor, particles sucked in from the outside are classified by four selected types of impactors (PM1, PM2.5, PM4, PM10) with a collection efficiency of 50%. After classification, one-third of the flow rate of particles entering the interior from the suction port is used as sheath air through a HEPA filter, and the remaining particles are sent to the detector. The sheath air enters the detector, covering the air containing the particles to be measured. The detector is protected by the sheath air, ensuring stable accuracy.

[0054] Particles that enter the detector pass through a laser, and the light scattered during this process is detected by a photodetector. The intensity of the scattered light depends on the particle concentration, particle size distribution, refractive index, shape, etc., and the signal from the photodetector is instantly converted to weight concentration and then saved (stored) in an internal logger. After detection, the particles are collected by a gravimetric filter and used to measure their weight and composition. Furthermore, a calibration coefficient is used to bring the measurement results closer to more accurate values.

[0055] 1, a plurality of light scattering type airborne particle counters 16 or a plurality of PM2.5 automatic measurement devices 17 are installed inside a room 11. There is no particular limit to the number or locations of the light scattering type airborne particle counters 16 or PM2.5 automatic measurement devices 17 installed in the room 11, and the number and locations are determined based on the volume of the room 11 or the layout of the room 11. Also, only one light scattering type airborne particle counter 16 or PM2.5 automatic measurement device 17 may be installed near the exhaust port 14 (near the exit) inside the room 11.

[0056] A measuring device identification number (humidifier identifier) ​​is set for each of the light scattering type airborne particle counters 16 or each of the PM2.5 automatic measurement devices 17, and the measuring device identification number is stored on the computer's hard disk. The measuring device identification number (humidifier identifier) ​​may be the individual identification number or model number of each light scattering type airborne particle counter 16 or each of the PM2.5 automatic measurement devices 17, or the computer may generate a unique identifier for each light scattering type airborne particle counter 16 or each of the PM2.5 automatic measurement devices 17, and the generated identifier may be used as the measuring device identification number.

[0057] The age of air measurement system 10 (age of air measurement method) measures numerical data (number data or concentration data) of tracer particles contained in the air (floating in space) in the room 11 using a light scattering type airborne particle counter 16 or an automatic PM2.5 measurement device 17 (PM2.5 measuring device), so that the numerical data of the tracer particles contained in the air in the room 11 can be accurately measured by the light scattering type airborne particle counter 16 or the automatic PM2.5 measurement device 17, and the accurate age of air in the room 11 (space) can be measured.

[0058] In the age-of-air measurement step (age-of-air measurement means), the age of air is measured at each measurement point 18 in the room 11 (space) of the ventilation system in Fig. 1 based on numerical data (number data or concentration data) related to tracer particles (tracer) contained in the air inside the room 11 of the ventilation system in Fig. 1 measured by the tracer measurement step (tracer measurement means) (light scattering type airborne particle counter 16 or PM2.5 automatic measurement device 17). In the age-of-air measurement step (age-of-air measurement means), a computer calculates the age of air at each measurement point 18 in the room 11 (space) of the ventilation system in Fig. 1 from the attenuation over time of the numerical data of the tracer particles (tracer) measured by the light scattering type airborne particle counter 16 or PM2.5 automatic measurement device 17 (tracer measurement step (tracer measurement means)).

[0059] A computer (not shown) is used for calculating the age of air in the age of air measuring step (age of air measuring means). The computer used is a physical computer that has a central processing unit (CPU or MPU) and memory (main memory and cache memory), has a built-in large-capacity hard disk, and operates on an independent operating system (OS). Input / output devices such as a display, touch panel, keyboard, and mouse are connected to the physical computer.

[0060] The cloud can also be used for calculating the age of air in the air age measuring process (air age measuring means). Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) can be used for the cloud. By using the cloud, IT resources can be used on demand from a cloud service platform via the Internet. The cloud is a virtual computer that has a virtual CPU or virtual MPU (central processing unit), a virtual main memory, and a virtual cache memory (virtual memory) and runs on an independent operating system (virtual OS), and a large-capacity virtual storage area is generated.

[0061] The control unit of the room 11, the control unit of the ultrasonic humidifier 15, the control unit of the light scattering type airborne particle counter 16, and the control unit of the PM2.5 automatic measurement device 17 are connected to the computer via signal lines (wired or wireless). An application for calculating the age of air is installed in the computer's memory. The age of air is calculated using the existing calculation formula shown below for the concentration decay method (step-down method). An example of the calculation formula for the age of air is as follows:

[0062] Formula for calculating age of air:

[0063]

number

[0064] The computer calculates the ventilation rate in the room 11 from the age of air calculated based on numerical data measured by a light scattering particle counter 16 or an automatic PM2.5 measurement device 17 installed near the exhaust port 14 (near the exit) of the room 11. The ventilation rate is calculated using the existing calculation formula shown below. The calculation formula for the ventilation rate is stored in the computer's memory. An example of the calculation formula is as follows:

[0065]

number

[0066] FIG. 2 is a diagram for explaining an example of a procedure for calculating the age of air in the room 11 of the ventilation system, and FIG. 3 is a diagram for explaining the procedure for calculating the age of air continued from FIG. 2. FIG. 4 is a diagram for explaining the procedure for calculating the age of air continued from FIG. 3, and FIG. 5 is a diagram for explaining the procedure for calculating the age of air continued from FIG. 4. FIG. 6 is a diagram for explaining the concentration decay method, which is an age of air measurement technique. FIG. 2 shows a tracer diffusion step (tracer diffusion means), and FIG. 3 shows a tracer concentration determination step (tracer concentration determination means). FIG. 4 shows a tracer measurement step (tracer measurement means), and FIG. 5 shows an age of air calculation step (age of air calculation means).

[0067] In the concentration decay method in the age of air measurement method (age of air measurement system 10), tracer particles are diffused in a room 11 (space), and when the concentration distribution of the tracer particles in the room 11 reaches a steady state, the diffusion of the tracer is stopped and decay of the number data or concentration data of the tracer particles over time is measured. As shown in Fig. 1, multiple ultrasonic humidifiers 15 are installed inside the room 11, and multiple light scattering type airborne particle counters 16 or multiple PM2.5 automatic measurement devices 17 are also installed. Tap water is supplied to the tanks of these ultrasonic humidifiers 15 at full range.

[0068] The following describes computer processing and input / output processing by a user as an example. The hard disk of the computer stores the volume "m3" of the room 11 (space) in Fig. 1, the ventilation airflow rate "m3 / s" of the conditioned air from the room 11 (space), the amount of tracer fine particles-containing minute liquid 12 generated from one ultrasonic humidifier 15 "m3 / s", the number of ultrasonic humidifiers 15 installed in the room 11 (space) and the humidifier identification numbers, the number of light scattering type airborne particle counters 16 or PM2.5 automatic measuring devices 17 installed in the room 11 (space), and the measuring device identification numbers of the light scattering type airborne particle counters 16 or PM2.5 automatic measuring devices 17, all associated with the room-specific identification number (room-specific identifier) ​​of the room 11.

[0069] The volume of the room 11 (space), the ventilation volume of the conditioned air from the room 11 (space), the amount of minute liquid 12 containing tracer particles generated from the ultrasonic humidifier 15, the number of ultrasonic humidifiers 15 installed, and the number of light scattering airborne particle counters 16 or automatic PM2.5 measuring devices 17 installed can be entered into a computer using an input device such as a touch panel, keyboard, or mouse, and can be changed as appropriate.

[0070] An icon indicating an application for calculating the age of air is output (displayed) on the computer start-up screen (not shown) output (displayed) on the display or touch panel. When this icon is clicked (tapped), a condition setting screen (not shown) for calculating the age of air is output (displayed) on the display or touch panel. On the condition setting screen, a measurement start button, a room sample image creation button, a numerical input button, and a cancel button are output (displayed). When the cancel button is clicked (tapped), the application ends (the same applies to the cancel button below). If a room sample image has already been created and the various numerical values ​​have been set, measurement of the age of air and ventilation rate can be started by clicking (tapping) the measurement start button.

[0071] To create a room sample image using a computer, click (tap) the Room Sample Image Creation button. When the Room Sample Image Creation button is clicked (tapped), a room sample image creation screen (not shown) is output (displayed) on the display or touch panel. A room sample image creation area, a sample confirmation button, a clear button, and a cancel button are output (displayed) on the room sample image creation screen. Using a touch panel, keyboard, or mouse, create multiple room sample images of any layout in which the ventilation system room 11 shown in Figure 1 is freely arranged in the room sample image creation area. Furthermore, clicking (tapping) the clear button clears the created room sample image.

[0072] After creating the room sample image, when the user clicks (tap) the sample confirmation button, the computer's central processing unit (CPU or MPU) generates a unique room-specific identification number (room-specific identifier) ​​for identifying the created room sample image, and stores the created room sample image on the hard disk in association with the room-specific identification number (room-specific identifier) ​​and the creation date and time. The computer's central processing unit generates a unique room-specific identification number (room-specific identifier) ​​for each room (each room sample image) every time a room sample image described below is created, and the generated room-specific identifier is used as the room-specific identification number. The age of air measurement method (age of air measurement system 10) uses a touch panel, keyboard, and mouse to create a variety of multiple room sample images of any layout, freely arranging the ventilation system room 11 shown in Figure 1, which simulates an actual room.

[0073] After storing the room sample images on the hard disk, the computer outputs (displays) a tracer generation / measurement point setting screen (not shown) on a display or touch panel. On the tracer generation / measurement point setting screen, a variety of room sample images (room sample top surface images) representing the room sample images of the ventilation system room 11 shown in Figure 1, a setting confirmation button, a clear button, and a cancel button are output (displayed).

[0074] After selecting a desired room sample image from multiple room sample images on the tracer generation / measurement point setting screen, multiple ultrasonic humidifiers 15 (tracer particle generation points) are attached (displayed) to any location (tracer generation point) of the room sample image by drag and drop using the touch panel, keyboard, or mouse, and multiple light scattering type airborne particle counters 16 (tracer particle measurement points 18) or multiple PM2.5 automatic measurement devices 17 (tracer particle measurement points 18) are attached (displayed) to any location (judgment point) of the room sample image. Clicking (tapping) the clear button clears the attached ultrasonic humidifiers 15, light scattering type airborne particle counters 16, or PM2.5 automatic measurement devices 17.

[0075] The age of air measurement method (age of air measurement system 10) utilizes a touch panel, keyboard, and mouse to freely attach (freely display) a plurality of ultrasonic humidifiers 15 (tracer particle generation sources) at any desired locations (tracer generation points) of the room sample image of the ventilation system room 11 shown in Figure 1, and to freely attach (freely display) a plurality of light scattering type airborne particle counters 16 (tracer particle measurement points 18) or a plurality of automatic PM2.5 measurement devices 17 (tracer particle measurement points 18) at any desired locations (judgment points) of the room sample image of the ventilation system room 11 shown in Figure 1.

[0076] Furthermore, the positions of the ultrasonic humidifiers 15 attached to the room sample image of the ventilation system room 11 shown in Figure 1 correspond to the positions of the ultrasonic humidifiers 15 installed in the actual room 11, and the light scattering type airborne particle counters 16 or the automatic PM2.5 measuring devices 17 attached to the room sample image of the ventilation system room 11 shown in Figure 1 correspond to the positions of the light scattering type airborne particle counters 16 or the automatic PM2.5 measuring devices 17 installed in the actual room 11.

[0077] When the Confirm Placement button is clicked (tapped) on the tracer generation / measurement point setting screen, the computer stores on the hard disk a room sample image of the room 11 with the attached ultrasonic humidifier 15, light scattering airborne particle counter 16 or PM2.5 automatic measurement device 17 attached, associated with the room specific identification number (room specific identifier) ​​and the date and time of attachment.

[0078] The age of air measurement method and age of air measurement system determine whether the concentration distribution of tracer particles (tracer) in the room 11 is steady at a plurality of points (judgment points) spaced a predetermined distance apart in the room 11 (space), so that the concentration distribution of tracer particles throughout the entire room 11 (space) can be measured with high accuracy and the steady state of the concentration distribution of tracer particles in the room 11 can be accurately determined.

[0079] The age of air measuring method and age of air measuring system diffuse tracer particles (tracer) into the room 11 from a plurality of points (tracer generation points) spaced a predetermined distance apart in the room 11 (space). This makes it possible to quickly diffuse the tracer particles throughout the entire room 11 (space) and to bring the concentration distribution of the tracer particles in the room 11 into a steady state while continuing ventilation operation.

[0080] Next, the computer outputs (displays) a numerical input screen (not shown) on the display or touch panel. The numerical input screen outputs (displays) a ventilation air volume input area for inputting the ventilation air volume of the conditioned air from the room 11 (space) (the actual ventilation air volume of the room 11), a humidifier number input area for inputting the number of ultrasonic humidifiers 15 installed, a generation amount input area for inputting the amount of liquid 12 generated by the ultrasonic humidifier 15 (the actual amount of liquid 12 generated by the ultrasonic humidifier 15), a room volume input area for inputting the volume of the room 11, a measurement point input area for inputting the number of light scattering type airborne particle counters 16 or PM2.5 automatic measurement devices 17 installed, a numerical value confirmation button, a clear button, and a cancel button. Clicking (tapping) the clear button clears the numerical values ​​input in each input area.

[0081] An ultrasonic humidifier 15 is attached at any position on the room sample image, and a light scattering type airborne particle counter 16 or an automatic PM2.5 measuring device 17 is attached, the ventilation air volume from the room 11 is entered in each numerical value input area, and the number of ultrasonic humidifiers 15 installed is entered in the installed humidifier number input area. Furthermore, the amount of liquid 12 generated by the ultrasonic humidifier 15 is entered in the generation amount input area, the volume of the room 11 is entered in the room volume input area, and the number of installed light scattering type airborne particle counters 16 or automatic PM2.5 measuring devices 17 is entered.

[0082] After inputting the required items in each input area, clicking (tapping) the numerical value confirmation button causes the computer to store on the hard disk the attached ultrasonic humidifier 15 (humidifier identification number), light scattering type airborne particle counter 16 or PM2.5 automatic measuring device 17 (measuring device identification number), the input numerical values ​​in association with the room specific identification number (room specific identifier) ​​and the input date and time. Note that the number of ultrasonic humidifiers 15 installed x the amount of liquid 12 generated by the ultrasonic humidifiers 15 is greater than the ventilation air volume from the room 11.

[0083] The attached ultrasonic humidifier 15 (humidifier identification number), the attached light scattering type airborne particle counter 16 or PM2.5 automatic measurement device 17 (measurement device identification number), a measurement start button, a cancel button, and a clear button are output (displayed) on the display or touch panel. When the measurement start button output on the display or touch panel is clicked (tapped), the computer measures the age of air at each measurement point 18 in room 11 in Figure 1 and starts measuring the ventilation rate of room 11 in Figure 1.

[0084] A specific method for measuring the age of air will be exemplified below. The computer sends a ventilation continuation signal to the control unit of the room 11, sends a start signal to the control unit of the ultrasonic humidifier 15 (the ultrasonic humidifier 15 actually installed in the room 11), and sends a start signal to the control unit of the light scattering type airborne particle counter 16 or the control unit of the PM2.5 automatic measurement device 17. The control unit of the room 11 that receives the ventilation continuation signal continues to operate the supply air fan, exhaust fan, and air conditioner. As the supply air fan, exhaust fan, and air conditioner continue to operate, the conditioned air (outside air) produced by the air conditioner is supplied (flows in) to the room 11 by the supply air fan, and the conditioned air in the room 11 is exhausted (flows out) to the outside by the exhaust fan, and the ventilation operation continues, air flows inside the room 11, and the air in the room 11 (space) is ventilated (air ventilation process (air ventilation means)).

[0085] The control unit of the ultrasonic humidifier 15 that receives the activation signal activates the ultrasonic humidifier 15. The ultrasonic vibrator of the ultrasonic humidifier 15 generates ultrasonic waves (vibrations), and the vibrations cause minute particles of liquid 12 containing tracer particles to be continuously released from the ultrasonic humidifier 15. As shown in FIG. 2, the minute particles of liquid 12 containing tracer particles gradually diffuse into the air in the room 11 (space) (tracer diffusion process (tracer diffusion means)).

[0086] In the tracer diffusion step (tracer diffusion means), minute liquid particles 12 containing tracer particles are diffused into the chamber 11 while the chamber 11 (space) is ventilated by the air ventilation step (air ventilation means). In the tracer diffusion step (tracer diffusion means), minute liquid particles 12 (tracer) containing tracer particles are diffused into the chamber 11 from a plurality of ultrasonic humidifiers 15 (tracer generation points) arranged at a plurality of positions spaced apart by a predetermined distance in the chamber 11 (space).

[0087] Furthermore, in order to increase the steady-state concentration in the chamber 11, the number of ultrasonic humidifiers 15 installed and the amount of tracer generated by the ultrasonic humidifiers 15 are adjusted, and the amount of minute liquid 12 (tracer) containing tracer microparticles generated in the tracer diffusion process (tracer diffusion means) is adjusted, and minute liquid 12 (tracer) containing tracer microparticles is generated in the chamber 11 by the tracer diffusion process (tracer diffusion means) until the concentration distribution of the tracer microparticles (tracer) in the chamber 11 reaches a steady state.

[0088] The age of air measuring method and age of air measuring system 10 adjusts the number of ultrasonic humidifiers 15 installed and the amount of tracer generated by the ultrasonic humidifiers 15 so that the steady-state concentration in the room 11 is high, and generates tracer in the room 11 until the concentration distribution of the tracer in the room 11 (space) reaches a steady state. Therefore, the concentration distribution of the tracer in the space can be reliably brought to a steady state, and there is no need to temporarily suspend the ventilation operation of the room 11 in order to bring the concentration distribution of the tracer in the room 11 to a steady state.

[0089] The control unit of the light scattering type airborne particle counter 16 or the control unit of the automatic PM2.5 measurement device 17 that receives the start signal starts the light scattering type airborne particle counter 16 or the automatic PM2.5 measurement device 17. The light scattering type airborne particle counter 16 starts measuring the number data (numerical data) of the tracer particles diffused in the room 11 in Fig. 1 before the ultrasonic humidifier 15 (tracer diffusion process (tracer diffusion means)) starts. Or, the automatic PM2.5 measurement device 17 starts measuring the weight concentration data (numerical data) of the tracer particles diffused in the room 11 in Fig. 1 before the ultrasonic humidifier 15 (tracer diffusion process (tracer diffusion means)) starts.

[0090] The control units of the light scattering type airborne particle counters 16 continuously transmit data on the number of tracer particles (numerical data) in the room 11 measured by the light scattering type airborne particle counters 16 to a computer in a time series. In some cases, the control unit of the light scattering type airborne particle counters 16 transmits data on the number of tracer particles (numerical data) to a computer at predetermined time intervals. In some cases, the control unit of the PM2.5 automatic measurement devices 17 continuously transmit data on the weight concentration of tracer particles (numerical data) in the room 11 measured by the PM2.5 automatic measurement devices 17 to a computer in a time series. In some cases, the control unit of the PM2.5 automatic measurement devices 17 transmits data on the weight concentration of tracer particles (numerical data) to a computer at predetermined time intervals.

[0091] The computer's central processing unit determines that a steady state has been reached when it determines that the change in the increase in the tracer particle count data (measurement numerical data) "pieces / m3" measured by the light scattering airborne particle counter 16 over time since the ultrasonic humidifiers 15 began to release the fine liquid 12 has become sufficiently close to zero (tracer concentration determination process (tracer concentration determination means)).

[0092] Alternatively, the computer's central processing unit determines that a steady state has been reached when it determines that the change in the increase in the tracer particle measurement concentration data (measurement numerical data) "μg / m3" measured by the PM2.5 automatic measurement device 17 over time since the ultrasonic humidifiers 15 began releasing the minute liquid 12 has become sufficiently close to zero (tracer concentration determination process (tracer concentration determination means)).

[0093] When the central processing unit of the computer judges that the measured numerical data has become steady numerical data state by the tracer concentration judgment process (tracer concentration judgment means), it transmits a stop signal to the control unit of the ultrasonic humidifier 15, and transmits a measurement continuation signal to the control unit of the light scattering type airborne particle counter 16 or the control unit of the PM2.5 automatic measurement device 17. Furthermore, it transmits a ventilation continuation signal to the control unit of the room 11.

[0094] As shown in FIG. 3, when the tracer particles (tracer) are in a steady state inside the chamber 11, the control unit of the ultrasonic humidifier 15 receives a stop signal and stops the ultrasonic humidifier 15.

[0095] The control unit of room 11 that receives the ventilation continuation signal continues to operate the supply air fan, exhaust fan, and air conditioner. As the supply air fan, exhaust fan, and air conditioner continue to operate, the supply air fan supplies (flows in) conditioned air (outside air) created by the air conditioner to room 11, and the exhaust fan exhausts (flows out) the conditioned air in room 11 to the outside, the ventilation operation continues, air flows inside room 11, and the air in room 11 (space) is ventilated (air ventilation process (air ventilation means)).

[0096] The control units of those light scattering type airborne particle counters 16 that have received the measurement continuation signal continue measuring the number data (measurement numerical data) of tracer particles (tracer) in the room 11 (space) by those light scattering type airborne particle counters 16 as a measurement for calculating the age of air (tracer measurement process (tracer measurement means)) immediately after the ultrasonic humidifier 15 (tracer diffusion process (tracer diffusion means)) is stopped. The control units of those light scattering type airborne particle counters 16 continuously transmit the measurement number data of the tracer particles in the room 11 (space) measured by each light scattering type airborne particle counter 16 to the computer in chronological order.

[0097] Upon receiving the measurement continuation signal, the control units of the PM2.5 automatic measurement devices 17 continue to measure the measurement concentration data (measurement numerical data) of the tracer particulate tracer in the room 11 (space) by those PM2.5 automatic measurement devices 17 as measurement for calculating the age of air (tracer measurement process (tracer measurement means)) immediately after the ultrasonic humidifier 15 (tracer diffusion process (tracer diffusion means)) is stopped, and continuously transmit the measurement concentration data of the tracer particulate tracer in the room 11 (space) measured by those PM2.5 automatic measurement devices 17 to the computer in chronological order.

[0098] Ventilation operation continues with the operation of the air conditioner, the intake fan, and the exhaust fan, and the air conditioned by the air conditioner (outside air) is supplied to the inside of the room 11 by the intake fan (air supply means), and the air in the room 11 is exhausted to the outside by the exhaust fan (exhaust means), so the concentration of tracer particles in the room 11 gradually decreases as shown in Figure 4. Therefore, the measured number data "pieces / m3" of tracer particles measured by the light scattering type airborne particle counters 16 gradually decreases over time, or the measured concentration data "μg / m3" of tracer particles measured by the PM2.5 automatic measurement devices 17 gradually decreases over time.

[0099] When the measured number data of tracer particles inside the room 11 (space) transmitted from the control unit of the light scattering type airborne particle counter 17 becomes 0 (the measured number data of tracer particles is the same as that of the outside air), or when the measured concentration data of tracer particles inside the room 11 (space) transmitted from the control unit of the PM2.5 automatic measurement device 17 becomes 0 (the measured concentration data of tracer particles is the same as that of the outside air), the central processing unit of the computer transmits a stop signal (measurement stop signal) to the control unit of the light scattering type airborne particle counter 16 or the control unit of the PM2.5 automatic measurement device 17. The control unit of the control unit of the light scattering type airborne particle counter 16 that receives the stop signal stops the activation of each light scattering type airborne particle counter 16. The control unit of the PM2.5 automatic measurement device 17 that receives the stop signal stops the activation of each PM2.5 automatic measurement device 17.

[0100] As shown in Fig. 4, the central processing unit of the computer calculates the age of air at each measurement point 18 in the room 11 (space) from the decay state of the numerical data of the tracer particles over time in the room 11 (space) in Fig. 1 (decay state from the steady state in which the tracer particles are diffused throughout almost the entire room 11 until the measured number data or measured concentration data of the tracer particles becomes 0) using the calculation formula for the age of air described above (air age calculation step (air age calculation means)). Furthermore, the central processing unit of the computer calculates the ventilation rate in the room 11 from the age of air calculated based on the measured number data of a light scattering type airborne particle counter 16 installed near the exhaust port 14 of the room 11 in Fig. 1 or the measured concentration data measured by an automatic PM2.5 measurement device 17 using the calculation formula for the ventilation rate described above (ventilation rate calculation step (ventilation rate calculation means)).

[0101] The computer stores on the hard disk the age of air at each measurement point 18 in the room 11 (space) calculated in the age of air calculation step (age of air calculation means) in association with the measuring device identification number of each light scattering type airborne particle counter 16 or the measuring device identification number of each PM2.5 automatic measuring device 17, the room specific identification number, and the calculation date and time. The computer stores on the hard disk the ventilation rate of the room 11 calculated in the ventilation rate calculation step (ventilation rate calculation means) in association with the room specific identification number and the calculation date and time.

[0102] After calculating the age of air and the ventilation rate, the computer outputs (displays) an age of air and ventilation rate output screen (not shown) on a display or touch panel. The age of air and ventilation rate output screen outputs (displays) the age of air at the tracer particle measurement point 18 near each light scattering type airborne particle counter 16 (tracer particle measurement point 18) or each PM2.5 automatic measurement device 17 (tracer particle measurement point 18) output (displayed) on the room sample image of the room 11 in Fig. 1, and also outputs (displays) the ventilation rate in the ventilation rate display area.

[0103] By looking at the age of air at each measurement point 18 (judgment point) output (displayed) on the display or touch panel, it is possible to know the locations in room 11 where the ventilation condition is good and the locations in room 11 where the ventilation condition is poor. By looking at the ventilation rate output (displayed) in the ventilation rate display area, it is possible to know the ventilation rate in room 11.

[0104] The age of air measurement method and age of air measurement system 10 diffuses tracer particles (tracer) inside a room 11 (space) while the room 11 is ventilated, measures numerical data (concentration) of the tracer particles in the room 11 into which the tracer particles have been diffused, and determines whether the concentration distribution of the tracer particles in the room 11 is in a steady state. If it is determined that the concentration distribution of the tracer particles in the room 11 is in a steady state, the diffusion of the tracer particles is stopped and ventilation of the room 11 is continued while measuring numerical data of the tracer particles diffused in the room 11, and calculates the age of air in the room 11 based on the attenuation of the tracer particles in the room 11 over time since the diffusion of the tracer particles was stopped. Therefore, there is no need to temporarily suspend ventilation operation for the room 11 when the tracer particles are diffused in the room 11 of the ventilation system, and the age of air in the room 11 can be measured while ventilation operation is continued.

[0105] The age of air measurement method and age of air measurement system 10 do not require starting and stopping ventilation operation at a predetermined timing, and can measure the age of air in a room 11 (space) without the trouble of starting and stopping ventilation operation. The age of air measurement method and age of air measurement system 10 calculates the age of air in the room 11 (space) from the attenuation of the numerical data of the tracer particles over time while measuring the numerical data of the tracer particles (tracer) for a predetermined measurement time after the diffusion of the tracer particles is stopped, and therefore can accurately measure the age of air in the room 11 by using the tracer particles.

[0106] The age of air measurement method and age of air measurement system 10 use tracer particles as a tracer that diffuse with the diffusion of minute liquids, and therefore can reliably and easily measure the age of air in the room 11. The age of air measurement method and age of air measurement system 10 use tracer particles as a tracer that diffuse with the diffusion of minute liquids, and therefore the calculation of the age of air in the room 11 (space) does not become complicated, and the age of air in the room 11 can be calculated easily.

[0107] The age of air measurement method and age of air measurement system 10 sets the measurement time for measuring the numerical data of the tracer particles after stopping the diffusion of tracer particles (tracer) while continuing ventilation to be the time from when the numerical data of the tracer particles decays until the numerical data becomes 0, and by setting the measurement time for measuring the numerical data of the tracer particles to the time from when the numerical data of the tracer particles decays until the numerical data becomes 0, it is possible to accurately capture the decay of the concentration of the tracer particles and to accurately measure the age of air in the room 11 (space).

[0108] The age of air measuring method and age of air measuring system 10 generate minute liquid containing tracer particles (tracer) by vibration energy of ultrasonic waves, and therefore can reliably and easily measure the age of air in a room 11 (space) by using tracer particles at room temperature without using a special heat source. The age of air measuring system and age of air measuring system 10 diffuse minute liquid containing tracer particles into the room 11 (space) by an ultrasonic humidifier while continuing ventilation, and after the minute liquid containing tracer particles is diffused into the room 11 to bring the concentration distribution of the tracer particles into a steady state, measure numerical data of the tracer particles for a predetermined measurement time after the diffusion of the tracer particles by the ultrasonic humidifier is stopped, and calculate the age of air in the room 11 from the attenuation of the numerical data of the tracer particles in the room 11 over time, and therefore can quickly measure the age of air in the room 11.

[0109] The age of air measurement method and age of air measurement system 10 uses a light scattering particle counter to measure numerical data of tracer particles in the room 11 (space) during a predetermined measurement time after the diffusion of a minute liquid containing tracer particles (tracer) is stopped, so that the numerical data of the tracer particles can be accurately measured by the particle counter and the accurate age of air can be measured in the room 11. The age of air measurement method and age of air measurement system 10 uses a PM2.5 measurement device that has a narrower measurement range than a particle counter but can accurately capture tracer particles of the same size as PM2.5 and has a relatively simple configuration, so that the numerical data of the tracer particles can be accurately measured by the PM2.5 measurement device and the accurate age of air in the room 11 (space) can be measured. [Explanation of symbols]

[0110] 10 Age of Air Measurement System Room 11 12 liquid 13 Air supply duct 14 Exhaust duct 15 Ultrasonic humidifier 16 Light scattering airborne particle counter 17 PM2.5 measuring device 18 Measurement points

Claims

1. A method for measuring the age of air in a given space by using a tracer, comprising: a tracer diffusion step of diffusing the tracer into the space while the space has been ventilated by the air ventilation step; a tracer concentration determination step of measuring a concentration of the tracer in the space into which the tracer has been diffused by the tracer diffusion step and determining whether the concentration distribution of the tracer in the space is in a steady state; a tracer measurement step of measuring numerical data of the tracer diffused into the space while stopping the diffusion of the tracer by the tracer diffusion step and continuing ventilation of the space by the air ventilation step if it is determined by the tracer concentration determination step that the concentration distribution of the tracer in the space is in a steady state; and an air age calculation step of calculating the age of the air of the space based on a state of attenuation of the tracer in the space over time since measurement of the numerical data of the tracer was started by the tracer measurement step.

2. 2. The method for measuring the age of air according to claim 1, further comprising the steps of: adjusting an amount of the tracer generated in the tracer diffusion step; and generating the tracer in the space by the tracer diffusion step until a concentration distribution of the tracer in the space reaches a steady state.

3. 3. The age of air measuring method according to claim 1, wherein the tracer concentration determining step determines whether the concentration distribution of the tracer in the space is in a steady state at a plurality of determination points spaced apart by a predetermined distance in the space.

4. 4. The method for measuring the age of air according to claim 3, wherein the tracer diffusing step comprises diffusing the tracer into the space from a plurality of tracer generation points spaced apart by a predetermined distance in the space.

5. 5. The method for measuring the age of air according to claim 4, wherein the tracer is a tracer particle that diffuses in association with the diffusion of a minute liquid, the tracer diffusion step diffuses a minute liquid containing the tracer particle into the space while continuing ventilation by the air ventilation step, the tracer measurement step measures numerical data of the tracer particle for a predetermined measurement time after the diffusion of the tracer particle by the tracer diffusion step is stopped while continuing ventilation by the air ventilation step, and the age of air calculation step calculates the age of air in the space from a state of attenuation of the numerical data of the tracer particle over time in the space.

6. 6. The age of air measuring method according to claim 5, wherein a measurement time for measuring the numerical data of the tracer particles by the tracer measurement step after stopping diffusion of the tracer particles by the tracer diffusion step while continuing ventilation by the air ventilation step is a time from attenuation of the numerical data of the tracer particles to the time when the numerical data becomes 0.

7. 7. The age of air measuring method according to claim 6, wherein the tracer diffusion step uses an ultrasonic humidifier that generates ultrasonic waves using an ultrasonic vibrator to create the minute liquid containing the tracer fine particles and diffuses the minute liquid into the space.

8. 8. The age of air measuring method according to claim 7, wherein the tracer measurement step uses a particle counter that has a measurement range including the particle diameters of the tracer particles diffused in the space by the tracer diffusion step and measures number data of the tracer particles floating in the space by a light scattering method, or a PM2.5 measuring instrument that has a measurement range including the particle diameters of the tracer particles diffused in the space by the tracer diffusion step and measures fine particulate matter floating in the space.

9. In an age of air measurement system for measuring the age of air in a specified space by using a tracer, the age of air measuring system comprises air ventilation means for ventilating the air in the space, tracer diffusion means for diffusing the tracer in the space, tracer concentration determination means for determining whether the concentration distribution of the tracer in the space is in a steady state, tracer measurement means for measuring numerical data of the tracer diffusing in the space during a predetermined measurement time, and age of air calculation means for calculating the age of air in the space based on the measured numerical data of the tracer, In the age of air measurement system, the tracer is diffused into the space by the tracer diffusion means while the air in the space is ventilated by the air ventilation means, and when the tracer concentration determination means determines that the concentration distribution of the tracer in the space is in a steady state, diffusion of the tracer by the tracer diffusion means is stopped and ventilation of the space by the air ventilation step is continued while the tracer measurement means measures numerical data of the tracer diffused into the space, and the age of air calculation means calculates the age of air in the space from the attenuation of the tracer over time in the space.

10. 10. The age of air measuring system according to claim 9, wherein the age of air measuring system adjusts an amount of the tracer generated by the tracer diffusing means and causes the tracer to be generated in the space by the tracer diffusing means until a concentration distribution of the tracer in the space reaches a steady state.

11. 11. The age of air measuring system according to claim 9 or 10, wherein the tracer concentration determining means determines whether the concentration distribution of the tracer in the space is in a steady state at a plurality of determination points at positions spaced apart by a predetermined distance in the space.

12. 12. The age of air measuring system according to claim 11, wherein the tracer diffusing means diffuses the tracer into the space from a plurality of tracer generation points at positions spaced apart by a predetermined distance in the space.

13. 13. The age of air measuring system according to claim 12, wherein the tracer is a tracer particle that diffuses in association with the diffusion of a minute liquid, the tracer diffusing means diffuses a minute liquid containing the tracer particle into the space while continuing ventilation by the air ventilation step, the tracer measuring means measures numerical data of the tracer particle for a predetermined measurement time after the diffusion of the tracer particle by the tracer diffusing means is stopped while continuing ventilation by the air ventilation means, and the age of air calculating means calculates the age of air in the space from a state of attenuation of the numerical data of the tracer particle over time in the space.

14. The age of air measurement system according to claim 13, wherein a measurement time for measuring the numerical data of the tracer particles by the tracer measurement means after stopping the diffusion of the tracer particles by the tracer diffusion means while continuing ventilation by the air ventilation means is a time from the attenuation of the numerical data of the tracer particles to the time when the numerical data becomes 0.

15. The age of air measurement system according to claim 14, wherein the tracer diffusion means uses an ultrasonic humidifier that generates ultrasonic waves using an ultrasonic vibrator to create the minute liquid containing the tracer fine particles and diffuses the minute liquid into the space.

16. The age of air measurement system according to claim 15, wherein the tracer measurement means uses a particle counter which has a measurement range including the particle diameters of the tracer particles diffused in the space by the tracer diffusing means and measures number data of the tracer particles floating in the space by a light scattering method, or a PM2.5 measurement device which has a measurement range including the particle diameters of the tracer particles diffused in the space by the tracer diffusing means and measures fine particulate matter floating in the space.

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