KR101178218B1 - Intermediate level control system of the double skin system - Google Patents

Abstract

The present invention is a double skin intermediate control system capable of controlling the slat angle of the blinds in the hollow bed and the airflow mode of the hollow bed, wherein the slat angle is controlled according to the HVAC operating mode and the sun altitude, and the hollow bed temperature and the room temperature. The air flow mode is controlled according to any one or more of the difference between the indoor and outdoor pressure difference, provides a double skin intermediate control system.
According to the present invention, the energy efficiency is much higher than that of the rule-based control method, so that the result of the energy performance when using the optimal control method that can only be applied to the academic field can be obtained, and at the same time, the problem of the optimum control method that is difficult to commercialize can be solved. have.

Description

Intermediate level control system of the double skin system

The present invention relates to a double skinned intermediate control system. More specifically, the present invention is a double skin intermediate control system capable of controlling the slat angle of the blinds in the hollow layer and the airflow mode of the hollow layer, wherein the slat angle is controlled according to the HVAC operating mode and the sun altitude, and the hollow layer The air flow mode is controlled according to any one or more of the difference between the temperature and the room temperature and the pressure difference between the indoor and outdoor.

The increase in the area of glass windows and the use of front curtain walls in office buildings, such as public offices, raises heat loss and losses through the building envelope and raises energy efficiency issues. As an alternative, eco-friendly skin technology is attracting attention. Eco-friendly skin technology means roof / wall greening system and skin system (double skin, electric shading device) to improve the insulation performance of building skin. Among them, research on double skin system is being actively conducted at home and abroad.

A typical double skin system consists of glass, blinds and ventilation dampers. It is difficult for the user to manually adjust the blinds and the ventilation dampers to a suitable condition for the indoor conditions. Therefore, the power member is used to control the blind slat angle and the ventilation dampers. Such a double skin system has the advantages of thermal comfort, energy saving, natural light, natural ventilation and the like. However, the effectiveness of the system is not dependent on the installation of the double skin system itself, but on how efficiently the system is controlled, achieving the cooling / heating load reduction through the double skin.

According to the prior art, a method of controlling the envelope system in an office building can be largely divided into (1) rule-based control and (2) optimal control. The rule-based control method is a control method mainly used in most real sites. The rule-based control method is controlled according to a condition or rule set by a user, and is also referred to as schedule control because a condition can be set according to time. The optimal control method is a control method that determines the most ideal control variables by applying an optimization technique.

The rule-based control method described above is a practical method in that it can be easily and simply applied, but it is insufficient in terms of performance such as energy and noise. In addition, the optimal control method is an ideal control method, but until now, the academic character (academic) is strong, and for various reasons it is difficult to apply the optimum control algorithm to the actual site or practical use.

The present invention is intended to solve the above problems.

More specifically, the present invention proposes a rule of a double envelope control algorithm of a non-residential building of an intermediate stage, which is more developed than the rule-based control method and satisfies the energy performance of the optimal control method.

In other words, the present invention proposes a control system that is practically applicable and commercially available or commercially available, such as a rule-based control method.

In order to solve the above problems, the present invention is a double skin intermediate control system capable of controlling the slat angle ( φ _slat ) and the air flow mode (AFR) of the blind in the hollow layer, HVAC operating mode and solar altitude The slat angle φ _slat is controlled in accordance with ( β ), and the airflow mode may be controlled according to any one or more of the difference between the hollow bed temperature T _ca and the room temperature T _in and the indoor / outdoor pressure difference ΔP . AFR) is controlled to provide a double skin intermediate control system.

According to the intermediate control method according to the present invention, the energy efficiency is much higher than that of the rule-based control method, and thus the energy performance when the optimal control method only for academic application is used can be obtained.

In addition, it is necessary to use an optimization solver of a specific software to solve the problem of an optimal control method that is difficult to commercialize.

Specific effects related to energy efficiency are described below.

1 is a schematic diagram illustrating control variables for control of a double skin system in the present invention.

One. Explanation of Control Variables and Terms

Control variables are selected to efficiently control the double skin system. 1 illustrates exemplary selected control variables. φ _slat is the slat angle of the blind in the hollow layer, AFR (Air Flow Regime) is the airflow mode of the hollow layer, and OR (Opening Ratio) is the opening ratio of the ventilation damper.

In the case of the slat angle φ _slat of the hollow layer, it is controllable from -90 ° to 90 °. Φ _slat = 90 ° if the blind is controlled to be perpendicular to the ground, φ _slat = 0 ° if the blind is controlled to be horizontal to the ground, φ _slat = β-90 ° if the blind is controlled to be perpendicular to the sun's altitude , Φ _slat = β when the blind is controlled to be parallel to the sun's altitude.

In the hollow bed airflow mode (AFR), indoor circulation (# 1, # 2), outdoor circulation (# 3, # 4), diagonal airflow (# 5, # 6, # 7, # 8), all open (# 9 ), All closed (# 10) can be controlled by all five. Upper and lower openings are present in each of the double sheaths of the hollow layer to control the airflow mode (AFR) under the control of a total of four openings.

More specifically, in the airflow mode (AFR) of FIG. 1, the left side of the drawing is the outdoor side and the right side is the indoor side. That is, diagonal airflows # 5 and # 6 are modes in which airflow is formed from indoors to outdoor, and diagonal airflows # 7 and # 8 are modes in which airflows are formed from outdoors to indoors. In addition, the diagonal airflow # 5, # 8 is a mode in which the outdoor upper opening and the indoor lower opening are opened, and the diagonal airflow # 6, # 7 is a mode in which the outdoor lower opening and the indoor upper opening are opened.

The above air flow direction is attributable to the indoor / outdoor pressure difference ΔP . The indoor / outdoor pressure difference ΔP described below is described as a positive value when the indoor pressure is higher than the outdoor pressure, and as a negative value when the indoor pressure is lower than the outdoor pressure.

The ventilation damper opening ratio OR is controllable from 0% to 100%.

In addition, "heating, ventilation, air-conditioning (HVAC) system" means a heating, ventilation, air conditioning system. In the present invention, "without HVAC operation" means a case where there is no operation of the air conditioner and the heater.

In addition, the "HVAC operating mode" described below consists of a cooling mode, a heating mode, and an intermediate stage mode. The cooling mode means that there is operation of the cooler, and the heating mode means that there is operation of the heater.

In addition, in order to effectively explain the control method, the "rule-based control method" may be referred to as "level I control method", and the "intermediate control method" according to the present invention is referred to as "level II control method". The "optimal control method" may also be referred to as "level III control method". Each of them means the same control method.

2.1 Description of rule-based control

Rule-based control is a method of controlling according to rules determined by intuition and experience. According to the prior art, when the amount of insolation measured by the solar insolation sensor on the roof of a building is 150 W / m ² or more, the blind ( φ _slat = 0 °) installed in the double skin hollow layer starts to close slowly, and thus, at 650 W / m ² . On reaching it closes up to the maximum angle ( φ _slat = 70 °). When the hollow bed air temperature measured by the temperature sensor inside the hollow bed is 28 ° C or more, the air flow mode (AFR) becomes an outdoor circulation in the cooling mode, and the ventilation dampers (OR) are all closed in the heating mode.

2.2 Description of Optimal Control

The optimal control method is the control considering the dynamic characteristics, and finds the most ideal control variable that minimizes the cost function for a given time. The methods vary, but the following describes the gradient method and exhaustive search method.

The first step in the search for optimal control parameters using the gradient method is the development of a mathematical model of the system to be controlled (see equation (a)). That is, the heat transfer and air flow phenomena that can occur in the double skin system are mathematically represented.

(a)

Here, x is a state variable, A is a state matrix, u is an input vector, and b is a load vector.

The second step is to select a cost function to quantitatively evaluate the performance of the double skin system (see equations (b) and (c)).

(b)

(c)

Here, Q _{cv, rd} is the indoor heat gain rate [W] due to convection and radiation of the glass window surface, Q _{sol, trans} is the solar radiation [W] transmitted to the indoor side, and Q _air is the indoor side due to the flow of hollow layer air. The heat gain rate [W] and Q _DA represent the amount of decrease in artificial lighting energy due to natural light [W]. The third step is to determine the optimal control variable that minimizes the cost function.

The exhaustive search method is a method of calculating the cost function for every possible combination of control variables at each sampling time interval and finding a combination of control variables that minimizes the cost function. This approach has the disadvantage that it takes a long time to calculate when the number of combinations of control variables is large, but it has the advantage of being mathematically simple because the process of calculating the solution of the optimization problem of equation (d) is omitted. .

(d) min J (φ _slat , AFR, OR)

st-90 ° ≤ φ _slat ≤ 90 °

AFR = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0 ≤ OR ≤ 100%

Rule-centered control does not take into account the dynamic characteristics of a double skin system, so it differs from the blind slat angle ( φ _slat ), the airflow mode (AFR), and the ventilation damper aperture ratio (OR) of optimum control. As a result of calculating the cost function by applying the rule-based control method and the optimal control method as described above, the optimum control was better in both the cooling mode and the heating mode in terms of energy performance than the rule-based control.

However, the gradient of the optimal control method uses the 'fmincon' function of the MATLAB opimization toolbox to solve the optimization problem of equation (d). The use of specific software and solvers can be an obstacle to the application or practical application of optimal control methods in the real world. In addition, the exhaustive search method does not require a specific solver such as a gradient method, but as described above, when the number of control variable cases increases, calculation time may be a problem, and since the method is based on a simulation model, it may be necessary to solve the problem of model calibration. Should be considered

Accordingly, the present invention proposes a level II intermediate envelope control method of energy level which is superior to rule-based control (level I control) and close to the optimal control level (level III control) based on the optimum control result.

3. Description of Double Skin Intermediate Control Method

Optimal control simulation of blind angle and airflow mode shows that the blind angle is dominated by the sun altitude ( β ), and the airflow mode (AFR) of the ventilation damper is the hollow bed temperature ( T _ca ) and the room temperature ( T ) of the double skin system. _in ) and indoor and outdoor pressure difference ( ΔP ). Therefore, the level II control algorithm calculates the sun's altitude to control the favorable blind angle for each indoor load condition, and calculates the indoor / outdoor pressure difference calculated based on the hollow layer measured using the sensor, the wind direction on the room temperature and the building envelope, and the wind speed. To control the airflow mode and aperture ratio of the ventilation damper.

3.1 Cooling mode: Summer (June-August) or air conditioning

In the case of the blind angle φ _slat , it is perpendicular to the sun's altitude during the day ( β > 0) to prevent the inflow of the sun as much as possible. Failure to keep the blind angle perpendicular to the ground ( φ _slat = 90 °) is a consideration of the reduction of artificial lighting energy through the inflow of daylight. At night ( β ≤ 0), it is perpendicular to the ground ( φ _slat = 90 °) to prevent heat gain (+) due to night radiation between the glass window surface and the room.

In the airflow mode, the hollow bed temperature ( T _ca ), the room temperature ( T _in ) and the indoor and outdoor pressure difference ( ΔP ) are measured or calculated to consider the effect of the hollow bed air flow on the room. If the hollow bed temperature of the day / night is higher than the room temperature, the damper is operated in the outdoor circulation mode (# 3, 4 of FIG. 1) to allow the hot air of the hollow bed to be discharged to the outside. If the hollow bed temperature during the day is lower than the room temperature, the indoor and outdoor pressure differentials are considered to block the inflow of hot air into the room. If the pressure difference is greater than zero, it operates in diagonal airflow mode (# 5 in FIG. 1) to allow the hot air to be discharged to the outside to reduce perfusion heat loss, and maintains the damper opening ratio at 50% to rapidly lower the room temperature. Prevents losing Otherwise, it is OR = 100%. When the pressure difference is less than zero, all of them are kept in the closed state (# 10 in FIG. 1) to use the hollow layer as a kind of heat insulation layer. If the room temperature at night is higher than the hollow bed temperature, all are kept closed (OR = 100%).

This is summarized in Table 1 below.

division Condition Execution φ _slat β > 0 φ _slat = β-90 ° β ≤ 0 φ _slat = 90 ° AFR β > 0 T _in <T _ca AFR # 3, 4 (outdoor circulation) T _in > T _ca ΔP> 0 AFR # 5 (diagonal airflow) ΔP <0 AFR # 10 (all closed) β ≤ 0 T _in <T _ca AFR # 3, 4 (outdoor circulation) T _in > T _ca AFR # 10 (all closed)

Control condition and contents in cooling mode

3.2 Heating mode: winter season (December to February) or start the heater

In the case of the blind angle φ _slat , during daytime ( β > 0), the solar altitude is horizontal ( φ _slat = β), so that solar inflow is maximized. At night ( β ≤ 0), it is perpendicular to the ground ( φ _slat = 90 °) to minimize heat loss (-).

In the airflow mode, when the temperature of the hollow layer in the daytime is higher than the room temperature, since the hot air of the hollow layer acts favorably in the room, the damper is operated in the indoor circulation mode (# 1, 2 in FIG. 1). Allow floor airflow to enter the room. When the hollow bed temperature during the day is lower than the room temperature, the dampers are all kept closed (# 10 in FIG. 1) to prevent the indoor warm air from being discharged to the outside. If the hollow bed at night temperature is higher than room temperature, indoor and outdoor pressure differentials are considered to block cold air inflow into the room. If the pressure difference is greater than zero, it is in diagonal airflow mode (# 6 in FIG. 1). Even if the room temperature is higher than the hollow bed temperature, if the pressure difference is greater than zero, the diagonal airflow mode (# 5 of FIG. 1), and if it is less than zero, all remain closed (OR = 100%). In diagonal airflow mode, the aperture ratio is maintained at 50%. Otherwise, OR = 100%.

division Condition Execution φ _slat β > 0 φ _slat = β β ≤ 0 φ _slat = 90 ° AFR β > 0 T _in <T _ca AFR # 1, 2 (indoor circulation) T _in > T _ca AFR # 10 (all closed) β ≤ 0 T _in <T _ca ΔP> 0 AFR # 6 (diagonal airflow) ΔP <0 AFR # 10 (all closed) T _in > T _ca ΔP> 0 AFR # 6 (diagonal airflow) ΔP <0 AFR # 10 (all closed)

Control condition and contents in heating mode

3.3 Mid-term Mode: Spring / Autumn (March-May / September-November)

If the HVAC system is operating in a building, it is controlled in the same way as the cooling / heating mode according to each mode. If the HVAC system is not running, the blind angle is kept at an angle that maximizes solar inflow when the hollow bed temperature is lower than room temperature (sunrise, sunset time), and is otherwise horizontal. Ventilation dampers in the absence of operation of the HVAC system are set in diagonal airflow mode and the airflow direction is determined by the pressure difference between the indoor and outdoor.

division Condition Contents φ _slat
AFR Air conditioner operation Same as cooling mode Radiator operation Same as heating mode φ _slat No HVAC operation T _in <T _ca φ _slat = 0 ° T _in > T _ca φ _slat = β AFR No HVAC operation T _in <T _ca AFR # 6, 7 (diagonal airflow) T _in > T _ca AFR # 5, 8 (diagonal)

Control Conditions and Contents in Intermediate Mode

Table 4 shows the components necessary to implement Level II and Level I and III double envelope control algorithms.

division ← practical / acaedemic → Ⅰlevel control II level control Ⅲlevel control Wasting exploration Optimal control Hardware (motor) ○ ○ ○ ○ sensor T _in ○ ○ ○ ○ T _out Ｘ ○ ○ ○ T _ca ○ ○ ○ ○ I _D , I _dif ○ Ｘ ○ ○ W _dir , W _spd Ｘ ○ ○ ○ Model (x = Ax + b) Ｘ △ ○ ○ Objective function (J) Ｘ Ｘ ○ ○ Solver (min J) Ｘ Ｘ Ｘ ○

Component Comparison by Control Strategy

(○: required, Ｘ: not required, △: only simple formula calculation required)

The control method of the level I can be implemented only if it is equipped with hardware such as electric motors and a sensor capable of measuring indoor and hollow layer temperatures and insolation. However, as described above, the level I control is suitable for indoor and outdoor conditions because it does not require a simulation model for predicting the response of the system and an objective function for quantitatively evaluating the performance, and is difficult in terms of performance due to difficulty in accurate control.

Level III control methods require not only hardware and sensors, but also a specific software solver that finds control models that minimize simulation models, objective functions, and objective functions. In addition, it can be said that it is difficult to put it to practical use as the user (or the owner) needs to purchase and install the specific software. On the other hand, the level II control minimizes the required sensors, is close to the level III performance, and can be immediately applied after verification of the mock-up building envelope.

4. Explanation of Simulation Results

The application of I, II, and III double envelope control algorithms to the lumped lumped model developed for optimal control enables simulation of winter (heating mode) and summer (cooling mode) for 57 hours (approximately 2.4 days). Proceeded.

Tables 5 and 6 below show the cost function [MJ / day] based on the simulation results and compare them by control method. Q [MJ] is the sum of timephased values, and Q _total [MJ] is the cost function representing the value of each cost element by Equation (b). ).

division Ⅰlevel control II level control Ⅲlevel control Wasting exploration Optimal control Q _{cv, rd} 11.99 4.00 4.83 1.83 Q _sol 0.58 0.84 0.63 0.10 Q _air 0 0 0 0 Q _DA 5.44 5.93 6.68 3.81 Q _total 7.12 -1.09 -1.21 -1.87

Cost Function Comparison by Control Method (Cooling Mode) [MJ]

division Ⅰlevel control II level control Ⅲlevel control Wasting exploration Optimal control Q _{cv, rd} -7.85 -1.66 -10.16 -6.74 Q _sol -5.63 -15.26 -16.66 -14.97 Q _air 0 -26.89 -22.67 -19.98 Q _DA -9.39 -9.39 -8.84 -12.57 Q _total -22.87 -53.21 -58.33 -54.26

Cost Function Comparison by Control Method (Heating Mode) [MJ]

In the case of the cooling mode, the cost function of the level II control is -1.09, which is almost the same as that of the level III control, and is significantly superior to the level I control.

In the heating mode, the cost function of the level II control method is -53.21, which is similar to that of the level III control, and is significantly superior to the level I control.

The exhaustive search method in the III-level control of the heating mode shows slightly better performance than the optimal control.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described specific embodiment. That is, a person having ordinary knowledge in the technical field to which the present invention belongs may make a number of changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications may be made. Equivalents should be considered to be within the scope of the present invention.

φ _slat : slat angle of blinds in hollow layer
Air Flow Regime (AFR): Airflow Mode in Hollow Layer
# 1, # 2: indoor circulation
# 3, # 4: Outdoor circulation
# 5, # 6, # 7, # 8: diagonals
# 9: open all
# 10: all closed
OR (Opening Ratio): Ventilation damper opening ratio
β (Solar Altitude): solar altitude
T _ca (Cavity Air Temperature): Hollow bed temperature
T _in (Indoor Air Temperature): Room Temperature
ΔP (Pressure Difference): Pressure difference
x (state vector): state variable
A (state matrix): state matrix
u (input vector): input vector
b (load vector): load vector
Q _{cv, rd} : Indoor heat gain rate due to convection and radiation of the glass window surface [W]
Q _{sol, trans} : Solar radiation transmitted to the indoor side [W]
Q _air : Indoor heat gain rate due to the flow of hollow bed air [W]
Q _DA : Reduction of artificial lighting energy due to natural light [W]

Claims (11)

A double skin intermediate control system capable of controlling the slat angle ( φ _slat ) of the blinds in the hollow bed and the airflow mode (AFR) of the hollow bed,
The slat angle φ _slat is controlled according to the HVAC operating mode and the sun altitude β
The air flow mode (AFR) is controlled according to any one or more of the difference between the hollow bed temperature ( T _ca ) and the room temperature ( T _in ) and the indoor and outdoor pressure difference ( ΔP ),
If the HVAC operating mode is cooling mode,
If the sun elevation is greater than zero, the slat angle φ _slat is controlled such that the blind is perpendicular to the sun elevation, and
When the sun altitude is less than or equal to 0, the slat angle ( φ _slat ) is controlled so that the blind is perpendicular to the ground,
Dual jacketed intermediate control system.
delete The method of claim 1,
If the HVAC operating mode is cooling mode and the solar altitude is greater than zero,
If the hollow bed temperature T _ca is greater than the room temperature T _in , the air flow mode AFR is controlled to be outdoor circulation # 3, 4,
When the hollow bed temperature T _ca is less than the room temperature T _in , and the indoor / outdoor pressure difference ΔP is greater than zero, the air flow mode AFR is controlled to be diagonal airflow # 5, and
When the hollow bed temperature ( T _ca ) is less than the room temperature ( T _in ) and the indoor and outdoor pressure difference ( ΔP ) is less than zero, the air flow mode (AFR) is controlled to be all closed (# 10). Made,
Dual jacketed intermediate control system.
The method of claim 3, wherein
When the HVAC operating mode is cooling mode and the sun altitude is below zero,
When the hollow bed temperature T _ca is greater than the room temperature T _in , the air flow mode AFR is controlled to be outdoor circulation # 3, 4, and
When the hollow bed temperature ( T _ca ) is less than the room temperature ( T _in ), characterized in that the air flow mode (AFR) is controlled to be all closed (# 10),
Dual jacketed intermediate control system.
A double skin intermediate control system capable of controlling the slat angle ( φ _slat ) of the blinds in the hollow bed and the airflow mode (AFR) of the hollow bed,
The slat angle φ _slat is controlled according to the HVAC operating mode and the sun altitude β
The air flow mode (AFR) is controlled according to any one or more of the difference between the hollow bed temperature ( T _ca ) and the room temperature ( T _in ) and the indoor and outdoor pressure difference ( ΔP ),
If the HVAC operating mode is heating mode,
If the sun elevation is greater than zero, the slat angle φ _slat is controlled such that the blind is horizontal with the sun elevation, and
When the sun altitude is less than or equal to 0, the slat angle ( φ _slat ) is controlled so that the blind is perpendicular to the ground,
Dual jacketed intermediate control system.
The method of claim 5, wherein
If the HVAC operating mode is heating mode and the solar altitude is greater than zero,
When the hollow bed temperature T _ca is greater than the room temperature T _in , the air flow mode AFR is controlled to be indoor circulation # 1, 2, and
When the hollow bed temperature ( T _ca ) is less than the room temperature ( T _in ), characterized in that the air flow mode (AFR) is controlled to be all closed (# 10),
Dual jacketed intermediate control system.
The method according to claim 6,
If the HVAC operating mode is heating mode and the solar altitude is below zero,
When the hollow bed temperature T _ca is greater than the room temperature T _in , and the indoor / outdoor pressure difference ΔP is greater than zero, the air flow mode AFR is controlled to be diagonal airflow # 6,
When the hollow bed temperature T _ca is less than the room temperature T _in , and the indoor / outdoor pressure difference ΔP is greater than zero, the air flow mode AFR is controlled to be diagonal airflow # 5, and
When the indoor and outdoor pressure difference ( ΔP ) is less than zero, characterized in that the air flow mode (AFR) is controlled to be all closed (# 10),
Dual jacketed intermediate control system.
The method according to claim 1, 3 or 4,
If the HVAC operating mode is Intermediate mode and the air conditioner is running,
Characterized in that any one or more of the slat angle ( φ _slat ) and the air flow mode (AFR) is controlled, such as when the HVAC operating mode is the cooling mode,
Dual jacketed intermediate control system.
8. The method according to any one of claims 5 to 7,
If the HVAC operating mode is Intermediate mode and heater is running,
Characterized in that any one or more of the slat angle ( φ _slat ) and the air flow mode (AFR) is controlled, such as when the HVAC operating mode is the heating mode,
Dual jacketed intermediate control system.
A double skin intermediate control system capable of controlling the slat angle ( φ _slat ) of the blinds in the hollow bed and the airflow mode (AFR) of the hollow bed,
The slat angle φ _slat is controlled according to the HVAC operating mode and the sun altitude β
The air flow mode (AFR) is controlled according to any one or more of the difference between the hollow bed temperature ( T _ca ) and the room temperature ( T _in ) and the indoor and outdoor pressure difference ( ΔP ),
If the HVAC operating mode is intermediate mode and there is no heating, ventilation, air-conditioning (HVAC) operation,
When the hollow bed temperature T _ca is greater than the room temperature T _in , the slat angle φ _slat is controlled such that the blind is horizontal with the ground, and
When the hollow bed temperature T _ca is less than the room temperature T _in , the slat angle φ _slat is controlled such that the blind is horizontal with the sun altitude,
Dual jacketed intermediate control system.
11. The method of claim 10,
If the HVAC operating mode is Intermediate mode and there is no HVAC running,
When the hollow bed temperature T _ca is greater than the room temperature T _in , the air flow mode AFR is controlled to be a diagonal air stream # 6, 7, and
When the hollow bed temperature ( T _ca ) is less than the room temperature ( T _in ), characterized in that the air flow mode (AFR) is controlled to be a diagonal air flow (# 5, 8),
Dual jacketed intermediate control system.

Images