FR2915558A1 - Thermal control function and air change function assuring automaton for e.g. institutional auditorium, has control unit and register controlled by control of centre, where automaton controls opening of register according to parameters - Google Patents

Abstract

The automaton (A) has a thermal control unit (6) and a mixing register (3) controlled by a control (7) of an air processing centre according to thermal comfort criterion. The automaton is sensible to air quality parameters e.g. carbon dioxide quantity measurements (8a-8c) or humidity measurements executed in exhaust air (A.Ev). The automaton controls opening of the register according to the parameters while maintaining management of the thermal comfort, where the register mixes fresh air (A.N) with recirculated air from the exhaust air, in priority according to quality of the exhaust air. The carbon dioxide quantity measurements are obtained on the fresh air, the exhaust air and the exit air of the thermal control unit, respectively.

Description

Automatic control and / or air exchange

  The present invention relates to a controller intended to provide both the thermal control and air renewal functions of a room, which can be adapted to an air handling unit ensuring one and / or the other said functions. In particular, the invention relates to such an automaton connected at least to a fresh air admission damper, an exhaust air extraction damper, a mixing damper for mixing fresh air with fresh air. recirculated air from the exhaust air, a blower blowing the mixture, an exhaust fan exhaust air and a thermal control unit to bring calories or frigories to said mixture before blowing into the room, these elements being controlled by a regulation of said plant according to thermal comfort criteria measured by the temperature of the fresh air, the temperature of the exhaust air and the temperature of the air leaving the thermal control unit, L The invention also relates to the equipment of an air handling unit providing one and / or the other of the thermal regulation and air renewal functions of a room and comprising an automaton according to the invention. Numerous systems are described in the scientific literature as permitting regulation of the ventilated airflow according to the presence measured in the room or building served. Technological variations can be differentiated by the assistance detection or counting system (optical measurement, infrared presence detection, carbon dioxide measurement, etc.) or in the flow control system (closing of registers of air, voltage variator on fans, frequency inverters, etc.). Some systems are patented and disclose integrated systems that include all elements of the ventilation function. They are offered as ventilation boxes incorporating functions of air quality measurement and ventilation control.

  The techniques of modulated ventilation or ventilation regulated according to need have been developed since the 1980s, mainly in the countries of Northern Europe and the United States of America. These techniques consist in enslaving the building ventilation regime to the real and measured needs of these buildings. By these techniques, we inject and extract less fresh air into the building. This saves the transport energy of this air, namely the electrical energy used by the exhaust fans or blowing. It also saves the energy of the indoor air treatment, namely its heating, cooling, humidification etc ... These savings are made without damaging the quality of indoor air in the building because the ventilation rate is adapted precisely to the real need of the building. For example, the amount of carbon dioxide in the room is measured to control the fan speed. These systems are cost-effective when they are installed on large air handling units that brew a volume of air whose economy of treatment repays the equipment. The breakeven point is generally considered for Air Handling Units (ATC) whose fresh air supply flow rate exceeds 2500 m3 / h. In the case of these large air handling units, the management of the injected air volume is complex because the air is used as a thermal fluid for heating or cooling the air. We can not manage the quantity of air brought into the building according to the only pollution of this air. Other factors necessary to maintain the expected climatic conditions of the local are to be taken into consideration. Experience shows that a system that only takes into account air quality to regulate the amount of fresh air supplied by a CTA is not operational to regulate the climatic comfort of the room if this CTA provides the air used as thermal fluid. However, no regulated ventilation system according to the need, integrates into these devices regulatory functions specific to the climate management of the premises. In addition, no system is proposed for grafting on air handling units regulated by a controller or by a centralized management of the building, this system being compatible with the existing regulation. The invention therefore aims to overcome these drawbacks by proposing a system capable of managing CTAs supplying air to premises with non-specific pollution, ie premises whose pollution is attributed only to the presence of human or animal occupants. According to the invention, a controller intended to provide both the thermal regulation and air renewal functions of a room, which can be adapted to an air treatment unit ensuring the one and / or the other of the said functions and comprising in whole or in part: - a fresh air admission damper, - an exhaust air extraction damper, - a mixing damper for mixing fresh air with fresh air. recirculated air from the exhaust air, - a blower blowing the mixture, - an extractor exhaust fan, and - a thermal control unit to bring calories or frigories to said mixture before blowing into the room these elements being controlled by a regulation of said plant according to thermal comfort criteria measured by the fresh air, the exhaust air and the air exiting the thermal control unit, is characterized by what said automaton is sensitive to air quality parameters other than temperature. Preferably, the automaton according to the invention controls, as a function of these quality parameters, the opening of: - the admission damper of the fresh air, - the extraction register of the evacuated air, and - the fresh air mixing damper with recirculated air in priority according to the quality of the evacuated air while maintaining the management of the thermal comfort.

  In addition, the automaton according to the invention controls the pulsation speed of the blower of the mixture and the exhaust fan of the exhaust air. In particular, said air quality parameters are measurements of the amount of CO2 and / or moisture in the exhaust air. More particularly, the automaton according to the invention also comprises means for humidifying the mixture of fresh air and recirculated air. More particularly still, the automaton according to the invention: first regulates the quality of the air of said room by increasing the opening of the admission registers with minimum ventilation speed until the regulation setpoint can be obtained more, then - gradually increases the blowing speed of the fans, then - checks the temperature setpoint, - regulates the intake and blowing speed according to the air quality or temperature that requires the most input in fresh air. In a preferred embodiment, the automaton according to the invention also comprises a natural cooling or heating mode making it possible to avoid the energetic supply of frigories or calories by which, before any implementation, the temperature is checked. outside and gradually opens the fresh air flow depending on the difference between the indoor temperature and the outside temperature. In another preferred embodiment, the automaton according to the invention 3.5 also comprises a nocturnal cooling mode by which the outside temperature is recorded around 6:00, and if this temperature exceeds a temperature setpoint, it is forced as a precautionary measure. ventilation to cool the room until the temperature is equal to the outdoor temperature plus 0.5 C with a maximum ventilation of 30 minutes. In yet another preferred embodiment, the automaton according to the invention also comprises a mode of purifying the air by which it forces a purification of the air of said room according to a schedule or a date where it is known that the quality of the outside air will be degraded during the day by triggering the ventilation during a determined period, for example for 30 minutes. Finally, the present invention relates to an air treatment unit providing one and / or the other of the thermal regulation and air renewal functions of a room and comprising an automaton according to any one of the forms of achievements presented above. The innovation presented is to adjust, on an air handling unit, the amount of ventilated air needed to maintain the air quality and expected climatic conditions of the room served. It is the coordination of air renewal functions and air-heating-air-conditioning functions, integrated into the same ventilation modulation system according to the measured needs of the room, which gives the system its character. inventive. Although this is not the primary purpose of the invention, an AAC comprising the automaton according to the invention may also for example be used to maintain a process temperature in an industrial premises, independently of any constraint on the quality of the 'air. The invention reveals numerous advantages and in particular the possibility of installing the automaton, which represents an autonomous system, on existing air treatment plants, provided with their own regulation which constitutes an important innovation.

  The system is primarily designed to integrate with an existing ACT with its own automation. We will speak of pre-existing automatism. This function is performed by a programmable industrial controller or by a Centralized Technical Management. The automaton according to the invention is an independent autonomous system which operates in parallel and in addition to the existing automation.

  The invention applies to the regulation of an air handling unit supplying an exclusive premises with non-specific pollution, where the occupation of the premises and the quality of the air are supposed to be homogeneous. The system can also manage multi-zone buildings, provided that certain criteria of homogeneity of the air are verified. It is considered that the room is heated or cooled by the CTA, which does not exclude that the room can be equipped with additional heating bodies, especially to overcome the losses to the walls.

  The invention will be better understood on reading the detailed description given hereinafter with reference to the drawings, in which: FIG. 1 represents a conventional CTA and its operating elements, FIG. 2 represents the CTA of FIG. of the automaton according to the invention, FIG. 3 represents the percentage of fresh air as a function of the amount of CO2 in the heating mode of the AHU controlled by the automaton according to the invention at the minimum speed of the variator; FIG. 4 represents the variation of the variator as a function of the amount of CO2 in heating mode of the AHU controlled by the automaton according to the invention once the CO2 threshold has reached at the minimum speed of the variator; FIG. variation of the variator as a function of the difference between the blowing temperature and the setpoint (here set at 40 ° C.); - FIG. 6 represents the variation of the variator as a function of the difference between the ambient temperature ( here fixed at 19 ° C) and the temperature of the air evacuated, - FIG. 7 represents the variation of the variator as a function of the difference between the temperature of the exhausted air and the air-conditioning temperature (here fixed at 24 ° C.) - FIG. 8 represents the variation of the variator as a function of the difference between the minimum temperature of the blown air and the blowing temperature; FIG. 9 represents the variation of the fresh air / recirculated air mixture as a function of the difference between the the temperature of the exhaust air and the ambient temperature (here set at 19 ° C.) - FIG. 10 represents the variation of the fresh air / recirculated air mixture as a function of the difference between the blowing temperature and the minimum air temperature. FIG. 11 represents the block diagram of the operation of the automaton on the fresh air damper control, - FIG. 12 presents the block diagram of the operation of the automaton on the air compressor. The purpose of this invention is to record the performance of the controller at an installation site during an assembly day in an auditorium. FIG. 1 shows an air handling unit for providing both the thermal regulation and air renewal functions of a room L. This comprises a fresh air admission damper 1 an exhaust air extraction damper 2, a mixing damper 3 for mixing fresh air with recirculated air coming from the exhaust air, a blowing fan of the mixture 4, an exhaust fan 5, and a thermal control unit 6 for supplying calories 6a or frigories 6b to said mixture before blowing into the room. These elements are controlled by a control 7 of said central unit. according to criteria of thermal comfort, essentially the temperature, or even the humidity rate or the blowing speed of the incoming air, measured for the fresh air AN, the air evacuated A.Ev. and for the air leaving the thermal control unit A.P. In FIG. 2, the CTA of FIG. 1 is completed by the automaton A object of the present invention. As shown in the figure, said automaton A is sensitive to air quality parameters other than temperature and in particular here, measurements 8a, 8b, 8c of CO 2 amount respectively on the fresh air AN, the air evacuated A.Ev. and the air leaving the thermal control unit AP The invention thus relates to: an autonomous industrial automaton providing the functions of acquisition, data recording, regulation, organ control, industrial programming and telephone network communication or Internet, - an air quality sensor installed in the exhaust duct or in the ventilated area. The probe is a carbon dioxide concentration probe in the ambient air or any other device making it possible to measure the assistance of the ventilated zone, temperature probes or temperature measurement recopies, namely temperature of the ambient air, forced air temperature, outside air temperature, extracted air temperature, and possibly, - humidity probes or ambient and external humidity measurement recopies, - logic inputs giving information on the operation of the AOC and the climatic or environmental conditions of the geographical location of the AOC (detailed below), - a fresh air proportioning system in the pulsed air, namely a motor supplying the air mixing dampers in the equipped air handling unit; - electronic frequency inverters or any other air flow control system provided by the fans. The whole can be integrated in an autonomous electrical cabinet.

  General regulation principle The PLC A initially manages only the control 3 mixing new air / air recirculated in the pulsed air then the control of two inverters B4, B5 of ventilation acting on the fans 4,5. The automaton A has no action on the three-way valve of the hot batteries 6a or 6b cold of the CTA. On the other hand, the pre-existing automatic system 7 gives its authority over the two controls of the automaton, in particular on the mixing command 3. It no longer provides mixing control as a function of temperature. The main input of the PLC is the air quality, but all the measurements mentioned above can control the outputs, according to a specific regulation process. Detailed regulation We will detail here different modes of operation of the PLC depending on the conditions and the desired regulation. In the following, the following abbreviations will be used to comment on the figures. These abbreviations will also be found in the figures. The figures are indicative and may vary depending on the desired regulation. • CO2: CO2 signal: directly expressed in ppm of CO2: 0 to 2000 ppm. • TSO: C blowout temperature • TEX: outdoor temperature, or fresh air in C. • TRE: exhaust air temperature, in C. • Drive setpoints: VAR, expressed as a percentage of the frequency requested on the 0-frequency range max (50 Hz). Note that we go directly from 0 to 30% (min frequency around 15 Hz). • Fresh air / extract air mixture: MAN, expressed as a percentage between 0 and 100%, with 0 being the all-air position (maximum recycling) and 100 all-fresh air position (no recycling). • Logical clock input: HOR, 0 if dormant, 1 if in operation. ^ Logic air conditioning input: CLIM, 0 if the air conditioning is off, 1 if it works. • Standby temperature setpoint: TVE, in C. The minimum temperature at which the room is maintained during the winter, even during the shutdown of the ACTs. Generally 14 C. • Ambient temperature set point: TAM, 19 C. • Air conditioning temperature setpoint: TCL, 24 C • Minimum temperature setpoint for the supply air TBS (temperature below which the 3 V valve heats up) forced air): 14 or 16 C (avoids condensation and fresh air flow). • Temperature setpoint triggering the night refresh: TRN = 16 C. In the event of a conflict on the value VAR or MAN, it is the command corresponding to the strongest bitrate that has authority.

  Sleep mode Enabled by the internal clock of PLC A or by a logic signal. Sleep mode means no one is supposed to enter the room in less than two hours.

  The installation is stopped but the room is kept at minimum standby temperature (14 C). HOR = O CTA in stop SiTRE> TVE no ventilation. Complete recycling. The room is hot enough. The existing control controls the 3-way valve to maintain the frost-free battery. VAR = O MAN = 0 If TRE <TVE just enough air is sent to warm the room. Complete recycling. VAR = MINI MAN = 0 Heating mode The A controller only takes care of the air quality. The CO2 first drives the opening of the register 3 in PID mode (with the drive B4 of the blower A at the minimum speed according to Figure 3) and the flow in PI mode by changing the speed of the blower A by the dimmer B4, according to FIG.

  The existing automation 7 is responsible for controlling the blowing temperature via the 3-way valve. It no longer has any authority over the opening of the register 3. HOR = 1 CTA in operation This loop can present kinetic problems because a too unstable beat of the registers can degrade the motors. It is therefore necessary to provide a significant time constant to avoid these beats If TSO> 40 C The blowing temperature becomes too great. This temperature is normally limited by the existing regulation of the hot water valves. Nevertheless, it is necessary to control the temperature of the blowing jet. The return temperature then controls the air speed, according to the diagram of FIG. 5, in the PI mode or in the P mode to bring as much heat with a greater air flow rate and less hot air.

  If the temperature can not be reached with the minimum air flow The air stream is too thin, the air flow must be increased, according to the diagram in Figure 6, to transmit the power of the hot battery. It takes a dead zone of 1 C and a Tl large enough not to regulate the temperature with the air flow.

  Air conditioning mode If CLIM = 1 and TRE> TCL The air conditioning is switched on and the room temperature is above the set point. The blowing air flow can not bring enough frigories. It must be increased by slaving it to the recovery temperature in PI mode. See figure 7 If CLIM = 1 and TSO <TBS The cold air jet is too intense. Cold shower effect and risk of condensation, even at low flow. In this case, it is necessary to increase the flow to decrease the difference between ambient temperature and pulsation temperature, in PI mode. (See Figure 8) In all these modes, the existing automation can find its usual instructions by driving only the 3-way valve.

  Natural cooling mode or free coolinq This is a major mode of ventilation that aims to save air conditioning energy. We try to refresh the room without air conditioning, gradually opening the flow of fresh air. The operation is identical in winter as in summer. In winter, we check that we do not breathe too cold air, reducing the supply of fresh air. For this we take as order the mini of the air shutter control of two controllers controlled at the ambient temperature and the blowing temperature. This is the mini that will be compared to the MAX in the higher order logic comparator. During air conditioning, this mode also prevails. If CLIM = 0 and TRE> TEX and TRE> TAM Open the mixing damper in fresh air.

  We take the mini of the two MAN controls that we compare to the MAX of the CO2 control. See Figures 9 and 10. No additional controls on airflow.

  If CLIM = 1 and TRE = TEX and TRE> TCL The scheme is identical. Turning on the air conditioning mode does not change this scenario. But in this case we compare the ambient temperature to the summer set temperature.

  We can design the same loop in free heating which means that we will send an outside air hotter than that of the local, before heating it. It should be noted that this mode, which is already quite rare in a normal building, is here even more exceptional because the single-zone is generally well insulated and its occupation rapidly raises the temperature

  Night refresh mode Operation in summer period, only.

  Principle: we record the outside temperature (fresh air temperature) at 6 o'clock in the morning (theoretical minimum of the day). If this temperature exceeds a set point TRN, ventilation is forced as a precaution to cool the room until the ambient temperature is equal to the outside temperature plus 0.5 C, with a maximum ventilation of half an hour .

  It is therefore necessary around 6 o'clock in the morning, to put the CTA out of sleep, to make it work in free cooling a little prolonged then to put the CTA dormant while waiting for its hour of operation.

  If CLIM = 1 and TRE> TRN As long as TRE> TEX + 0.5 HOR 1 VAR = 100% MAN = 100% HOR = O

  Air purification mode Designed for urban air handling units, especially in metropolitan areas with air quality monitoring systems. The principle is based on the fact that urban pollution undergoes diurnal variations due to transport fluctuations: peaks are reached between 8 am and 10 am and then between 17 and 19 pm. The idea is to force the air filling rooms by ventilating for a maximum of half an hour, before the peaks of pollution. This leaves a reserve of unpolluted air in the room, while waiting for service. The air quality monitoring networks transmit a forecast for an air quality indicator to the central server controlling several systems such as PLC A. This indicator follows appropriate processing. According to this one, a specialized software decrees that it is necessary to address an order of purification of the air. This command is sent to PLC A via the internet or modem. A simpler method is to trigger the air purge command based on a schedule or schedule where we know that the air quality will be degraded during the day. If one is in regime of purification of the air the control is the following one: As long as counter of operation <30 minutes HOR 1 VAR = 100% MAN = 100% HOR = 0 The automaton according to the invention allows the continuous recording ambient quality measurements that ensure that the ventilation has always been in compliance with the regulatory requirements and the requirements of the occupants of the room. This is an important asset for obtaining technical advice or regulatory certification.

  The parameterization of the regulation is carried out at the end of an instrumented audit undertaken beforehand on the CTA. This is based on the recording of pressure, temperature and carbon dioxide measurements contained in the various airs 11 managed by the CTA as well as on the energy consumptions noted. The audit also calculates the profitability of the equipment on the site. Figures 11 and 12 show a synoptic summary of the different modes of operation of the controller according to the invention. They present in particular the successive steps of each of these operating modes according to the instructions applied and the variables to be considered. In FIG. 11, for example, are presented the sequences and parameters that will control the Mixture Air Fresh / Air Extracted (MAN), the variator being at a minimum. In parallel, Figure 12 shows the sequences and parameters that will control the drives (VAR) of the fans, once the imposed guidelines can no longer be met by playing only on the mixture (MAN). The first sequence of FIG. 11 (PID1) shows that a measurement of CO2 is carried out. This measurement is compared to the setpoint 600-CO2max1 from which the mixer selector MAN starts to play. The variable HOR = 1 specifies that the PLC is in operation. Once this setpoint is exceeded, that is to say that it can no longer be respected by only playing on the opening of the register of the mixture, then we move to the first sequence of Figure 12 (PID2). In this one, we measure the CO2 which must remain lower than CO2maxl-CO2max2.

  The other sequences are interpreted in the same way according to the defined variables and the determined mode of operation of the automaton. Hereinafter, an example of a project for implementing the automaton according to the invention is presented. The automaton is intended for a CTA of an auditorium.

  The local is a prestigious auditorium with a capacity of 160 seats. The nominal fresh air flow rate is 8,800 m3 / h. The heating, air conditioning, transport of fresh air correspond to an energy consumption of about 80 MWh / year. The audit shows that the occupancy rate of this room is low but classic for this type of use: 15%.

  Predictive balance of the equipment: - Gain of thermal comfort by significant decrease of the air flows under the seats of the listeners. -Measured decrease in air turbulence. - Reduction of ventilation noise, during the phase of penetration in the auditorium: 2 to 3 dB acoustics. - Ambient temperature and sanitary quality of the air undisturbed. 13 - Energy gains: about 30 MWh thermal and 8 MWh electric smoothed over a year. This test for implementing the automaton that is the subject of the invention gave the results illustrated in FIG. 13 during an assembly. FIG. 13 comprises several curves plotted according to a system of rectangular axes including, on the abscissa, the time expressed. in hours, and in ordinates, on the vertical axis of right, the scale of temperature in (, whose graduations also serve as percentage of consumed energy, and, on the vertical axis of left, the CO2 content of the air expressed in ppm.

  The temperature, maintained at 21 C is plotted in solid line. The CO2 measurement, drawn in dashed lines, expresses the quality of the air (the regulatory threshold is 1000 ppm). The energy consumed, expressed as a percentage of the energy used without the equipment is plotted in bold: the energy expenditure is adapted to the variations of assistance. At some sites, the energy savings achieved should allow the equipment to be depreciated in less than 6 months.

Claims (9)

claims   . 1. PLC (A) intended to provide both the thermal regulation and air renewal functions of a room (L), which can adapt to an air handling unit ensuring one or the other or both functions and comprising: - a fresh air admission damper (1), - an exhaust air extraction damper (2), - a mixing damper (3) for mixing the air fresh air with recirculated air from the exhaust air, - a blower of the mixture (4), - an exhaust fan of the exhaust air (5), and - a thermal control unit ( 6) to supply calories (6a) or frigories (6b) to said mixture before blowing in the room, these elements being controlled by a regulation (7) of said plant according to thermal comfort criteria measured by the temperatures of the room. fresh air (AN), exhaust air (A.Ev.) and air leaving the thermal control unit (AP), characterized in that said Tomato (A) is sensitive to air quality parameters selected from, or in the control of, the amount of CO2, or measurements of moisture, or both, in the exhaust air according to these quality parameters, opening the fresh air mixing damper (3) with recirculated air in priority according to the quality of the air evacuated while maintaining the thermal comfort management.   2. An automaton according to claim 1, characterized in that it also controls, according to these quality parameters, the opening of: - the fresh air admission register (1), and - the register of extraction of exhaust air (2).   3. PLC according to one of claims 1 or 2, characterized in that it controls the pulsation speed of the blower blower mixture (4) and the exhaust fan exhaust air (5).   4. An automaton according to any one of claims 1 to 3, characterized in that it also comprises humidifying means of the mixture of fresh air and recirculated air. 15   5. An automaton according to any one of claims 1 to 4 characterized in that it: - first regulates the air quality of said room by increasing the opening of the admission registers at minimum ventilation speed up to that the regulation setpoint can no longer be obtained, then - progressively increases the blowing speed of the fans, then - checks the temperature setpoint, - regulates the intake and the blowing speed according to the air quality setpoint or temperature that requires the most fresh air intake.   6. An automaton according to any one of claims 1 to 5, characterized in that it also comprises a cooling mode or natural heating to avoid the energetic supply of frigories or calories by which, before any implementation. In this case, the outside temperature is checked and the fresh air flow is progressively opened as a function of the difference between the indoor temperature and the outside temperature.   7. An automaton according to any one of claims 1 to 6, characterized in that it also comprises a night cooling mode by which the outside temperature is recorded at 6:00, and if this temperature exceeds a temperature setpoint, it forces to Preventative ventilation to cool the room until the temperature is equal to the outside temperature plus 0.5 C with a maximum ventilation of 30 minutes.   8. An automaton according to any one of claims 1 to 7, characterized in that it also comprises a purification mode of the air by which it forces a purification of the air of said room according to a schedule or a date when it is known that the quality of the outside air will be degraded during the day by triggering the ventilation during a determined period.   9. Air handling unit providing one or both of the functions of thermal regulation and air renewal of a room, characterized in that it comprises a controller according to any one of Claims 1 to 8.