JP2004270971A - Method for controlling stratification height of stratified air conditioning and stratified air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stratified air conditioning system capable of performing treatment of heat radiation by thermal load satisfactorily, saving energy, and holding a living space in clean environment always and to provide a method for controlling its stratification height. <P>SOLUTION: This stratified air conditioning system is provided with an air conditioner 1 for feeding air incorporating a heat exchanger 2, an air feeding unit 6 for feeding outside air cooled by the heat exchanger 2 into a lower indoor part having thermal load L from a blow-out port 6a at low speed, and an exhaust port 19 for exhausting air in an upper indoor part to the outside of a room. A cooling unit 9 is provided on a floor surface, and a secondary cooling pipe 10 in which cooling medium after passing through the heat exchanger 2 flows through a flow rate control means 11 is arranged inside the cooling unit 9. Here, the amount of outside air introduced into the room is the same as the amount of indoor air exhausted from the exhaust port 19. In this system, it is possible to control stratification height forming a boundary face of a lower part low temperature air zone and an upper part high temperature air zone by controlling flow rate of cooling medium flowing into the cooling unit 9. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for controlling the stratification height of stratified air conditioning in which the stratification height in a displacement ventilation system is controlled according to the floor surface temperature. Further, the present invention relates to a stratified air conditioning system for sending a cooling medium after passing through a heat exchanger in an air supply air supply unit to a floor surface cooling unit.
[0002]
[Prior art]
In recent years, a displacement ventilation system has been introduced from Northern Europe as a ventilation system. This system combines mechanical ventilation with natural ventilation using the ventilation power due to the temperature difference of air. That is, when fresh air at a temperature slightly lower than room temperature is supplied from the floor level, this air is heated by a heating element (heat load) in the room and becomes an ascending airflow. Utilizing the power of the rising airflow, dust and gas emitted from the pollution source are conveyed in the ceiling direction and exhausted from the ceiling level to keep the living area in a clean environment (Non-Patent Document 1).
As a similar air-conditioning system, as shown in FIG. 1, air-conditioned air blown out at a low wind speed from an air supply unit a having an air outlet near the floor reaches the heat load b without disturbing the indoor air flow as much as possible. Then, there is stratified air conditioning that is induced by a heat plume (heat rising flow) generated by the heat load b, rises in the ceiling direction, and is discharged from an exhaust port c provided on the ceiling surface. In this stratified air conditioning, a temperature stratification is generally formed at a low temperature near the floor and at a high temperature near the ceiling.
The above-described replacement ventilation system and stratified air conditioning are disclosed in Patent Documents 1 and 2, for example.
[0003]
[Non-patent document 1]
"Handbook of Air Conditioning and Sanitary Engineering", 3 Air Conditioning Equipment Design, pp. 252 to 254, edited by the Society of Air Conditioning and Sanitary Engineers, 13th edition, November 2001
[Patent Document 1]
Japanese Patent No. 2862149
[Patent Document 2]
JP 2000-310431 A
[0004]
[Problems to be solved by the invention]
By the way, the above-described high-temperature stratified area (heat pool) involves heat radiation to the floor surface, which causes a rise in the temperature of the floor surface and the vicinity thereof. When the temperature near the floor rises, the temperature of the conditioned air supplied from the air supply unit to the room increases, and may increase before reaching the heat load scattered in the room, satisfying the heat load treatment. Problems such as being unable to perform the operation. As a result, the supply air volume Q_S<Heat plume air volume Q_PThen, the high-temperature heat reservoir goes down, that is, the “stratification height” H, which will be described in detail later, is reduced (FIG. 2).
When pollutants such as odors and dusts are generated from the heat load, the indoor air in the part lower than the stratification height is clean, but in the part higher than the stratification height, it becomes a mixed area, and the pollutant concentration is lower than the exhaust port concentration. The density is almost equal to In addition, in a living space such as an office, the stratification height boundary is almost equal to the height of the respiratory range of a standing human body, so if the stratification height decreases, there is a possibility of inhaling contaminated air. Comes out. Therefore, under the above-described stratified air conditioning, one of the issues is to raise, that is, raise, the boundary surface of the stratification height.
As one means for raising the boundary surface of the stratification height, it is conceivable to first increase the supply air volume. For example, by setting the air supply air amount> the heat plume air amount, the boundary surface of the stratification height can be raised. However, an increase in the amount of supply air leads to an increase in the amount of outdoor air introduced, resulting in an increase in energy consumption for outside air processing. As means for increasing the amount of supply air, it is conceivable to increase the size of the indoor air supply air conditioner, but in addition to increasing the processing energy of the outside air load, the transfer power of the blower, the supply air duct and the air supply unit are increased. Becomes a problem.
[0005]
Therefore, an object of the present invention is to solve the above-mentioned problems, and it is possible to satisfactorily treat heat radiation due to a heat load without increasing the size of an air-conditioning air supply unit, save energy, and reduce living space. It is an object of the present invention to provide a method for controlling the stratification height of stratified air conditioning and a stratified air conditioning system that can always maintain a clean environment.
The present inventors have conducted intensive studies in order to solve the above-mentioned problem, and as a result, provided a floor cooling unit connected to a heat exchanger built in the air supply air-conditioner by piping, and sent to this unit. The above object has been achieved by controlling the flow rate of the cooling medium to be liquefied.
[0006]
[Means for Solving the Problems]
According to the present invention, outdoor air is heat-exchanged by an air-cooling heat exchanger, and cooled air is supplied to a lower part of the room at a wind speed of 0.6 m / sec or less, and is heated by a heat load existing in the room. In the method of controlling the stratified height of the stratified air conditioning, which discharges substantially the same amount of outdoor air as the introduced outdoor air outside the room, the cooling medium after passing through the heat exchanger is supplied to the floor cooling unit. The stratification height is controlled by controlling the flow rate of the cooling medium to be supplied into the floor surface cooling unit per unit time by sending the liquid to cool the floor surface, comparing the floor surface temperature with the set temperature, and controlling the flow rate per unit time. Is controlled.
Further, the present invention provides an air cooling heat exchanger for exchanging heat with outdoor air, an air supply duct for introducing the outdoor air, and an air cooled by the heat exchanger into a room having a heat load from an outlet. In a stratified air-conditioning system that includes an air supply unit that supplies air at a wind speed of 0.6 m / sec or less and an exhaust port that discharges indoor air to the outside of the room, the above-described blowing is performed below the stratification height in a stratified air-conditioning system that replaces room air with outdoor air. The outlet is located, the above-mentioned exhaust port is installed above the stratification height, and the secondary cooling pipe through which the cooling medium after passing through the heat exchanger in the air supply air supply is sent through the flow control means , A floor cooling unit provided behind the floor.
[0007]
Here, the stratification height is defined as the height from the floor at which the air volume of the supply plume and the air volume of the heat plume generated by the thermal load become equal. In order to obtain the stratification height H, assuming that the heat load is a heating element cylinder (L) serving as a virtual point heat source S shown in FIG._P) And supply air volume (Q_S) Is equal to the heating value (P) of the heating element and the ambient air temperature (T₀), The distance (Z) from the virtual point heat source S is obtained according to the following equation (1), and can be further calculated from the following equations (2) and (3) and the height of the heating element.
Equation 1 Q_P  = K (g / C_P・ Ρ ・ T₀)^1/3[P ・ Z]^1/3
Equation 2 Z₀  = 0.8D / 2 (tan 12.5 °)
Equation 3 Z = Z₀  + H-D / 3
Q_P: Plume air volume [m³/ S]
K: constant (Cederwall 0.14, Scaret 0.19)
g: Gravitational acceleration [m / s²] (9.81)
C_P: Specific heat [kJ / kg · K] (1.007)
ρ: Density [kg / m³] (1.176)
T₀: Ambient air temperature [K]
P: Heat value [kW]
Z: Distance from virtual point heat source [m]
D: diameter of heating element [m]
h: distance [m] from the top surface of the heating element
The floor surface temperature in the present invention includes not only the temperature of the floor surface in a strict sense, but also the temperature of the floor material.
[0008]
[Action]
The method for controlling the stratification height of the stratified air conditioner according to the present invention is a conventional stratified air conditioner, which compares a floor surface temperature with its set temperature, sends a liquid to a floor surface cooling unit after passing through an air cooling heat exchanger. It controls the flow rate of the cooling medium per unit time.
Specifically, when the floor temperature is higher than the set temperature, the flow rate control means increases the flow rate of the cooling medium that sends the floor cooling unit to lower the floor temperature. When the floor surface temperature decreases, the amount of heat plume air generated by the heat load (natural flow rate) decreases, so that the stratification height can be increased. If the floor temperature is lower than the set temperature, the flow rate control means reduces the flow rate of the cooling medium to increase the floor temperature. When the floor surface temperature increases, the amount of hot plume air increases, so that the stratification height can be reduced.
According to such a control method of the present invention, by maintaining the floor surface temperature at a predetermined temperature, the stratification height can be maintained at a desired height, so that the living space below the stratification height is always maintained. It can be replaced with clean air. Further, the cooling unit that cools the floor surface has a function of processing the heat radiation from the upper heat reservoir peculiar to the stratified air conditioning and preventing the temperature of the conditioned air supplied to the room from rising. In addition, the floor cooling unit not only processes heat radiation from the heat load existing in the room, but also reduces the solar radiation load, and also processes heat radiation from each wall surface of the room.
[0009]
The control method of the present invention controls the flow rate of the cooling medium to the floor cooling unit, compares the room temperature with the set temperature, and compares the flow rate of the cooling medium passing through the air-cooling heat exchanger per unit time. Is preferably controlled (claim 2). The latter flow control is performed as follows.
If the room temperature is higher than the set temperature, the flow rate of the cooling medium passing through the heat exchanger is increased by an appropriate flow rate control means to lower the supply air temperature. As a result, the indoor temperature decreases, so that the amount of heat plume generated by the heat load decreases, and the stratification height can be increased. When the room temperature is lower than the set temperature, the flow rate of the cooling medium is reduced by an appropriate flow control means to increase the room temperature. When the room temperature increases, the amount of hot plume air increases, so that the stratification height can be reduced. As described above, when the floor surface temperature and the room temperature are simultaneously controlled, the stratification height can be stably maintained at a predetermined height.
[0010]
The present invention also provides a conventional stratified air conditioning system, in which a cooling medium after passing through a heat exchanger in a supply air conditioner is fed through a flow control means to a secondary cooling pipe on the back side of the floor surface. A floor cooling unit is provided. According to this stratified air-conditioning system, the flow rate control means controls the flow rate of the cooling medium to the floor cooling unit, so that the same effect as the invention of the method of controlling the stratified height is exerted. The same applies to the invention of the control method, but the occupant feels discomfort due to the cold radiation from the floor surface because the floor surface is cooled by the cooling medium which has been appropriately heated and passed through the heat exchanger. There is no such thing.
In the stratified air conditioning system of the present invention, as a flow control means, a three-way valve is interposed in the pipe between the heat exchanger and the secondary cooling pipe, and the three-way valve and the return pipe of the secondary cooling pipe are connected by pipe connection. It is preferable to bypass the cooling medium (claim 5). In this stratified air conditioning system, for example, a sensor for detecting the floor surface temperature is provided, and the floor surface temperature is compared with the set temperature as described above, and the cooling medium sent to the secondary cooling pipe per unit time is provided. By increasing or decreasing the flow rate, the stratification height can be controlled.
Furthermore, it is preferable that a two-way valve is interposed in a pipe between the heat exchanger and the three-way valve or an upstream pipe of the heat exchanger (claim 6). In this stratified air conditioning system, for example, a sensor for detecting the indoor temperature is provided, and the indoor temperature is compared with the set temperature as described above, and the flow rate of the cooling medium passing through the air-cooling heat exchanger per unit time is provided. , The stratification height can be controlled stably.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
In FIG. 4, reference numeral 1 denotes an air supply air conditioner installed outdoors, which is provided with an air cooling heat exchanger 2, an air heater 3, and an air supply fan 4. As the heat exchanger 2, a coil type, a multi-tube type, a heat exchanger in which a fin tube is wound in a meandering shape on the surface of the heat exchanger body, or the like is used, and the inside of the heat exchanger 2 is cooled with cold water, brine, or the like. The medium is sent. The air heater 3 is constituted by a hot water coil type heat exchanger, an electric heater, or the like, but is activated when the outdoor air is lower than a predetermined temperature, and can be omitted.
Outdoor air (for example, outdoor air) introduced into the air conditioner 1 by the air supply fan 4 is supplied to the air supply unit 6 through the air supply duct 5. The air supply unit 6 may be installed on a floor surface or a wall surface, and has a function as a plenum chamber. From the outlet 6a of the air supply unit, the air cooled by the heat exchanger 2 is blown at a low wind speed along the lower part of the room, particularly along the floor surface, so as not to disturb the airflow in the room. This supply air velocity is in the range of 0.05 to 0.6 m / sec, and usually in the range of 0.1 to 0.3 m / sec. Further, the supply air volume per unit time is increased or decreased according to the size of the room to be air-conditioned.
The air-cooling heat exchanger 2 does not necessarily need to be built into the air conditioner 1, but may be interposed in the air supply duct 5 or configured as a coil unit to supply air cooled by a separately provided fan. You may send air.
[0012]
An upstream pipe of the air-cooling heat exchanger 2 is connected to a cooling medium flowing from a cold heat source (not shown), for example, a cold water outgoing pipe 7, and a downstream side of the floor cooling unit 9 through a pipe 8. Is connected. In the cooling unit 9, a secondary cooling pipe 10 into which the cooling medium after passing through the heat exchanger 2 flows is disposed on the back side of the floor. Examples of the cooling unit 9 include a cooling unit in which a mat in which a secondary cooling pipe 10 is embedded is embedded in a floor material for a double floor, and a cooling unit in which a secondary cooling pipe 10 is embedded in a floor slab. Instead of the embedding method, a cooling unit 9 of a floor blowing method that blows out the outdoor air heat-exchanged in the secondary cooling pipe 10 from the floor surface can be used. In this case, the blowing air velocity is substantially the same as the supply air velocity, and is preferably in the range of 0.2 to 0.5 m / sec. Further, the size of the cooling unit 9 is desirably the same size as the floor surface, but need not necessarily be the same size. For example, when a heat load described later is concentrated, the heat load may be laid only on the heat load and the floor around the heat load.
A pipe 8 connecting the heat exchanger 2 and the cooling unit 9 controls a flow rate of the cooling medium to the cooling unit 9 per unit time according to the floor surface temperature, and controls a flow rate of maintaining the floor surface at a predetermined temperature. Means are interposed. That is, the floor surface temperature can be adjusted by controlling the flow rate control means, and is maintained at a temperature equal to or lower than the blowing temperature from the air supply unit 6 after reaching the steady state.
[0013]
Examples of the flow control means include a normal flow control valve, a three-way valve with a flow control function, a diaphragm valve that detects floor temperature and automatically adjusts the opening of the valve, and FIG. 3 shows an example of the three-way valve. Is illustrated. The three-way valve 11 includes a valve element A connected to the heat exchanger 2, a valve element C connected to the secondary cooling pipe 10, and a valve element B communicating with a bypass pipe 13 that bypasses the cooling unit 9. Further, it is preferable to provide another flow control means in the pipe 8 between the heat exchanger 2 and the flow control means such as the three-way valve 11 or the outflow pipe 7 on the upstream side of the heat exchanger 2. Examples of such flow control means include a two-way valve 14 having a flow control function shown in FIG. 4, a flow control valve, a diaphragm valve which detects room temperature and automatically adjusts the opening of the valve. Instead of these valves, a pump (not shown) may be interposed in the outgoing pipe 7 or the return pipe 12 downstream of the bypass pipe 13 to control the driving force.
A control method when the illustrated three-way valve 11 and the two-way valve 14 provided in the pipe 8 are used as each flow control means will be described. The three-way valve 11 compares the temperature detected by the floor surface temperature sensor 15 that detects the temperature of the floor surface or floor material with a set value in which a desired floor surface temperature is stored by a control element 16 such as a microcomputer. The opening of the valve body C is adjusted. More specifically, when the floor surface temperature measured by the sensor 15 is higher than a set value, the opening degree of the valve body C is increased, and when the measured floor surface temperature is equal to or lower than the set value, the valve is opened. The body C is closed or its opening is reduced. The opening of the two-way valve 14 is adjusted by comparing a temperature detected by the room temperature sensor 17 with a set value in which a desired room temperature is stored by a control element 18 such as a microcomputer. Specifically, as the room temperature measured by the sensor 17 is higher than the set value, the opening degree of the valve body of the two-way valve 14 is increased, and when the measured value of the room temperature is equal to or lower than the set value, The valve body is closed or its opening is reduced. However, when the valve body of the two-way valve 14 and the valve body C of the three-way valve 11 are closed, the floor surface temperature becomes higher than the set value in a short time, so that the heat exchanger 2 and the cooling unit 9 and the cold heat source It is preferable to open each valve body in a state where each valve body is squeezed so that the cooling medium always circulates through the gap.
[0014]
Generally, in a living space such as a house or an office, or in a large space such as an atrium, a heat load L exists as various heat sources such as lighting equipment, OA equipment, and electric products in addition to residents. As shown in FIG. 1, a thermal plume is generated from the thermal load L, and a temperature stratification of a low-temperature region and a high-temperature region is formed on a lower portion of the living space. The warmed air in the upper stratified area (heat reservoir) is exhausted from the room by an exhaust fan 21 through an exhaust duct 20 from an exhaust port 19 installed in, for example, a ceiling or a wall surface of the temperature stratified area.
In the present invention, after both the room and the floor reach the set temperature, the air supply capacity of the air supply fan 4 and the exhaust fan 21 are made substantially the same, and the air supply amount from the air outlet 6a and the air outlet 19 The exhaust air volume from the air is always equalized. That is, the stratified air-conditioning system of the present invention is of a constant air volume type, and the temperature of the cooling medium can be adjusted as necessary to change the surface temperature of the heat exchanger 2 and the accompanying supply air temperature. Further, the air introduced into the air supply unit 6 does not need to be entirely derived from the outside, and a part of the indoor air may be returned, purified, cooled, and reused.
[0015]
As a modified example of the floor surface temperature sensor 15, a radiation thermometer can be installed on the ceiling surface to monitor the floor surface temperature. Further, in the case of floor blowing air conditioning, the floor surface temperature can be analytically determined from the measurement value of the temperature sensor disposed inside the double floor and the temperature of the room temperature sensor 17 in consideration of the thermal resistance of the floor material. . On the other hand, the room temperature sensor 17 is preferably installed near the stratification height H (± 15 cm), particularly below the stratification height H. In addition, instead of the room temperature sensor 17, the air supply temperature sensor (22) for detecting the temperature of the air discharged from the air supply air conditioner 1 or the air supply unit 6, or the temperature of the heat reservoir or the same as the temperature is considered. An exhaust temperature sensor (23) for detecting the temperature of the exhaust air to be discharged can also be used.
In the stratified air conditioning system of the present invention, a secondary cooling pipe 10 into which a cooling medium after passing through a heat exchanger 2 in an air supply air conditioner 1 flows in through a flow rate control means is disposed behind the floor surface. Since the floor cooling unit 9 is provided, the heat radiation from the upper heat reservoir peculiar to the stratified air conditioning is processed, and the temperature of the conditioned air supplied from the air supply unit 6 is prevented from rising. The cooling unit 9 is configured to process heat radiation from the heat load L existing in the room, reduce the solar radiation load, and process heat radiation from each wall surface of the room, in addition to the process of heat radiation from the upper heat reservoir. Has an effect to be performed together.
[0016]
The present invention also provides a cooling medium that has passed through the heat exchanger 2 and is sent to the floor cooling unit 9, and the cooling medium is supplied to the cooling unit 9 by comparing the floor temperature with the set temperature. By controlling the flow rate per hour, the stratification height H can be controlled. A method of controlling the stratification height of the stratification air conditioner will be described with reference to FIG. FIG. 5 shows an example in which the above-described three-way valve 11 is used as a flow control means for controlling the flow rate of the cooling medium to the floor cooling unit 9.
In this control method, the floor temperature is set to 20 ° C., and the set value and the temperature T detected by the floor temperature sensor 15 are set._SPFWhen the floor temperature is higher than 20 ° C., the opening of the valve element C of the three-way valve 11 is increased. Thus, the flow rate of the cooling medium flowing into the secondary cooling pipe 10 after passing through the heat exchanger 2 increases. As a result, the floor surface temperature acts in a lowering direction, and the amount of plume air generated by the thermal load L also decreases, so that the stratification height H increases. Also, the floor surface temperature T detected by the sensor 15_SPF          When the temperature is lower than the set temperature of 20 ° C., the opening degree of the valve body C is reduced. As a result, the flow rate of the cooling medium to the secondary cooling pipe 10 decreases, so that it acts in a direction in which the floor surface temperature increases, and the stratification height H decreases. In this manner, the floor surface temperature is maintained at about 20 ° C., and the stratification height H is also maintained at a substantially predetermined height.
A flow control valve can be used as the flow control means. In this case, the floor temperature T_SPFWhen the opening degree of the flow control valve is increased or decreased according to the above, the flow rate of the cooling medium flowing into the secondary cooling pipe 10 per unit time increases or decreases, and the stratification height H can be increased or decreased in the same manner as described above. Further, a diaphragm valve in which the opening of the valve is automatically adjusted by detecting the floor surface temperature may be used.
[0017]
In the present invention, it is more preferable to control the stratification height by combining the control of the floor surface temperature and the control of the room temperature. The control of the room temperature is performed by controlling the flow rate of the cooling medium to the heat exchanger 2 per unit time. As such a flow control means, for example, a method using the above-described two-way valve 14 can be mentioned.
Specifically, the indoor set temperature is set to 26 ° C., and the set value and the temperature T detected by the room temperature sensor 17 are set._SPRWhen the room temperature is higher than 26 ° C., the opening of the valve body of the two-way valve 14 is increased. Thereby, the flow rate of the cooling medium passing through the heat exchanger 2 increases. As a result, the temperature of the air supply blown out from the air supply unit 6 decreases, and the indoor temperature decreases. Therefore, the amount of plume air generated by the thermal load L also decreases, and the stratification height H increases. Further, the temperature T detected by the sensor 17_SPRIs lower than the set temperature of 26 ° C., the opening of the two-way valve 14 is reduced. As a result, the flow rate of the cooling medium passing through the heat exchanger 2 decreases, so that the room temperature increases and the stratification height H decreases. When both the floor surface temperature and the room temperature are controlled in this way, the stratification height H is more stably maintained at the predetermined height.
A flow control valve can be used as the flow control means for controlling the flow rate of the cooling medium passing through the heat exchanger 2. In this case, the room temperature T_SPRWhen the opening degree of the flow control valve is increased or decreased according to the above, the flow rate of the cooling medium passing through the heat exchanger 2 is increased or decreased, and the stratification height H can be increased or decreased in the same manner as described above. Further, a diaphragm valve in which the opening degree of the valve is automatically adjusted by detecting the room temperature may be used.
When the floor temperature is set to 20 ° C. and the indoor temperature is set to 26 ° C., as an example, the cooling medium inlet temperature of the heat exchanger 2 in the air supply air conditioner 1 is about 7 ° C. After the replacement, the outlet temperature of the cooling medium rises to about 12 ° C. When this cooling medium is sent to the secondary cooling pipe 10, the cooling medium outlet temperature of the secondary cooling pipe 10 increases to 15 to 19 ° C.
[0018]
Generally, indoor air is clean in a region lower than the stratification height H, but in a region higher than the stratification height H, the contaminant concentration is approximately equal to the exhaust outlet concentration. FIG. 6 shows the relationship of the height from the floor surface to the dimensionless concentration of the stratified air conditioning according to the present invention including the floor cooling unit 9 and the conventional non-unit ventilation ventilation air conditioning not including the unit. In FIG. 6, when floor cooling is not performed, the vertical concentration distribution of a certain point in the room in the conventional replacement ventilation air conditioning is represented by a non-dimensional concentration concentration, as shown by a solid line. On the other hand, the vertical distribution of the dimensionless concentration according to the present invention with floor cooling is represented by a dotted line. The measurement point is the height [m] from the floor surface indicated by the plot in the graph. The dimensionless density is defined by the following equation.
([Measurement point concentration]-[Air supply concentration]) / ([Exhaust gas concentration]-[Air supply concentration])
Comparing the two-dimensional densities, according to the present invention, the non-dimensional concentration at the measurement point at the center of the graph at the same height from the floor is low, and the original stratification height H rises upward. I'm moving. This means that the cleanliness at the measurement point has been improved. Therefore, according to the control method of the present invention, since the boundary surface of the stratification height H can be easily raised, the stratification height H is maintained so as to be always higher than the height of the respiratory region of the standing human body. The living space below the stratification height H can always be replaced with clean air.
The method for controlling the stratification height according to the present invention employs a method in which cold water (well water) is passed through a floor material normally used for floor heating in a large space such as an atrium as the floor cooling unit 9. Thereby, heat radiation from the heat reservoir in the upper part of the large space can be processed. According to this cooling method, the lower space such as the atrium can be maintained in a favorable environment.
[0019]
【Example】
Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.
In FIG. 7, reference symbol R indicates a living space of 4.5 m × 4.5 m × 2.6 m, and simulated loads P 1 to P 4 having a height of 1.3 m exist at the positions shown in FIG. I do. At the center of one side surface (wall surface) of the living space R, a rectangular parallelepiped air supply unit 6 for supplying outdoor air heat-exchanged in the air supply air conditioner (1) to the room through an air supply duct 5. Is installed on the floor. The air supply unit 6 has air outlets 6a on three sides except the wall surface side. From the outlet 6a, the outdoor air is blown into the lower area of the room at a wind speed of 0.2 m / sec. In addition, a floor cooling unit 9 of a non-blowing type is laid on the entire floor surface, and an exhaust port 19 is provided on a ceiling on the back side. From the exhaust port 19, the same amount of upper room air as the amount of supply air is discharged outside the room. Further, in the present embodiment, a floor surface temperature sensor (15) is arranged between the meandering secondary cooling pipes (10), and the room temperature is placed on the wall surface 1.5 m above the floor surface facing the air supply unit 6. A sensor (17) is arranged.
The simulated calorific value of each of the simulated loads P1 to P4 is 255.7 W. The supply air volume of the supply unit 6 is 403.0 m.³/ H, and the supply air temperature is 20.4 ° C. When the floor temperature and the indoor temperature at the detection points of the respective sensors were set to 20 ° C. and 26 ° C., respectively, and the air conditioning operation was performed according to the flowchart shown in FIG. 5, the stratification height (H) was 1.55 m. Was controlled. Further, the temperature of the floor surface was maintained at 20.7 ° C., and the exhaust temperature was 27.9 ° C. In addition, the graph of FIG. 6 assumes that the contaminants are generated between the simulated loads P1 to P4, and the dimensionless concentration of the height from the gas concentration measurement point M shown in FIG. Is qualitatively determined. FIG. 7A shows the height direction of the measurement point as a density distribution reference point D.
[0020]
【The invention's effect】
The stratified air-conditioning system and the stratification height control method of the present invention provide a cooling unit on the floor in stratified air-conditioning, so that heat radiation from the upper heat reservoir specific to stratified air-conditioning and heat radiation from the surrounding wall surface In addition, the heat radiation due to the heat load existing in the room can be treated to reduce the amount of plume air generated from the heat load, thereby increasing the stratification height. In addition, it is possible to suppress a rise in temperature near the floor surface due to radiant heat from the upper heat reservoir or heat load, and prevent a rise in the temperature of the conditioned air supplied from the supply unit. Furthermore, since the cooling medium which has passed through the air-cooling heat exchanger and has been appropriately heated is sent into the floor-surface cooling unit, there is no discomfort due to cold radiation from the floor.
Further, according to the present invention, the stratification height can be easily controlled by adjusting the flow rate of the cooling medium flowing into the floor surface cooling unit, so that the living space below the stratification height is always replaced with clean air. can do.
In the present invention, the air supply unit is controlled by lowering the floor surface temperature by the floor surface cooling unit when the height is controlled to be the same as the boundary surface of the stratification height formed in the conventional replacement air conditioning system including only the air supply unit. Since the amount of air supplied from the air can be reduced, stratified air conditioning that saves energy can be achieved. For example, if the floor temperature in the conventional replacement air-conditioning system without a floor cooling unit is lowered by 1 to 5 ° C., the amount of supplied air can be reduced by 5 to 15%. Moreover, since the temperature of the cooling medium for cooling the floor surface may be equal to or lower than the temperature of the air blown from the air supply unit, the cooling medium after passing through the heat exchanger in the air supply air conditioner is used. There is no need to add a new cold heat source.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of general stratified air conditioning.
FIG. 2 is an explanatory diagram showing a relationship between a supply air volume and a heat plume air volume.
FIG. 3 is an explanatory diagram for calculating a plume air volume;
FIG. 4 is an explanatory diagram of a stratified air conditioning system showing an embodiment of the present invention.
FIG. 5 is a flowchart showing an example of a method for controlling a stratification height according to the present invention.
FIG. 6 is a graph showing the relationship between the height from the floor and the dimensionless concentration of the stratified air conditioning of the present invention having a floor cooling unit and the conventional replacement ventilation air conditioning not having the unit.
FIG. 7A is a schematic diagram showing an embodiment of the present invention, and FIG. 7B is a layout diagram of a simulated load and an air supply unit existing in the living space.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air supply air conditioner, 2 ... Air cooling heat exchanger, 5 ... Air supply duct, 6 ... Air supply unit, 6a ... Outlet, 8 ... Piping, 9 floor cooling unit 10 secondary cooling pipe 11 three-way valve (flow control means) 12 return pipe 13 bypass pipe 14 two way Valve (flow control means), 15: Floor temperature sensor, 17: Room temperature sensor, 19: Exhaust port, H: Stratified height, L: Thermal load.

Claims (6)

The outdoor air is heat-exchanged by the air-cooling heat exchanger, and the cooled air is supplied to the lower part of the room at a wind speed of 0.6 m / sec or less, and the upper part of the room is heated by the heat load existing in the room. In the method of controlling the stratified height of the stratified air conditioner, which discharges substantially the same amount of outdoor air as the outdoor air into which the air has been introduced, the cooling medium that has passed through the heat exchanger is sent to the floor cooling unit. To control the stratification height by cooling the floor surface, comparing the floor surface temperature with the set temperature, and controlling the flow rate of the cooling medium sent into the floor surface cooling unit per unit time. A method for controlling the stratification height of stratified air conditioning. Controlling the flow rate of the cooling medium to the floor cooling unit, comparing the room temperature with the set temperature, and controlling the flow rate of the cooling medium passing through the air cooling heat exchanger per unit time. The method for controlling the stratification height according to claim 1. The flow rate of the cooling medium to the floor cooling unit is controlled via a three-way valve, and the flow rate of the cooling medium to the heat exchanger is controlled via a two-way valve. Control method of stratification height. An air-cooling heat exchanger for exchanging heat with outdoor air, an air supply duct for introducing the outdoor air, and an air cooled by the heat exchanger into a room having a heat load from an outlet through an outlet of 0.6 m / sec or less. In a stratified air conditioning system that includes an air supply unit that supplies air at a wind speed and an exhaust port that discharges indoor air to the outside, wherein the air outlet is located below the stratification height, The above-mentioned exhaust port is installed above the height, and the secondary cooling pipe through which the cooling medium after passing through the heat exchanger in the air supply air conditioner is sent through the flow control means is placed on the back side of the floor surface. A stratified air conditioning system comprising a floor cooling unit disposed therein. The flow rate control means comprises a three-way valve interposed in a pipe between the air cooling heat exchanger and the secondary cooling pipe, and is cooled by a bypass pipe connecting the three-way valve and a return pipe of the secondary cooling pipe. The stratified air conditioning system according to claim 4, wherein the medium is bypassed. The stratified air conditioning system according to claim 5, wherein a two-way valve is interposed in a pipe between the heat exchanger and the three-way valve or in an upstream pipe of the heat exchanger.

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