GB2551714A

GB2551714A - Cleanroom control system and method

Info

Publication number: GB2551714A
Application number: GB1611107.2A
Authority: GB
Inventors: Wallace Robert; Chen Shuji
Original assignee: Energy Efficiency Consultancy Group Ltd
Current assignee: Energy Efficiency Consultancy Group Ltd
Priority date: 2016-06-27
Filing date: 2016-06-27
Publication date: 2018-01-03
Also published as: CN109312941B; GB201611107D0; US20190234631A1; EP3475625B1; SG11201811173VA; WO2018002589A1; EP3475625A1; DK3475625T3; CN109312941A; AU2017289701B2; PL3475625T3; ES2902870T3; AU2017289701A1

Abstract

A control system for controlling air volume so as to maintain a desired concentration of airborne contamination in a cleanroom. Where the cleanroom is supplied by a HVAC system 12 which supplies treated air to the cleanroom. The control system feature sensing means 48 for sensing a concentration of non-viable particles or viable particles in real time or near real time. Processing means are also provided for comparing the sensed concentration of non-viable particles or viable particles against the desired concentration of airborne contamination and outputting at least one control signal to the HVAC system 12 based on the comparison. Optionally, the processing means receives energy price data or usage data. Optionally, there is provide one or more secondary sensing means for sensing an environmental condition or process condition or HVAC system condition in real time or near real time.

Description

(71) Applicant(s):

Energy Efficiency Consultancy Group Limited Suite 9, The Green, MACCLESFIELD, Cheshire, SK10 1JN, United Kingdom (72) Inventor(s):

Robert Wallace

Shuji Chen (56) Documents Cited:

EP 2527755 A2 US 5195922 A US 20160076780 A1 US 20060234621 A1 (58) Field of Search:

INT CL B01L, F24F, H01L Other: EPODOC, WPI

KR 101489221 B US 4530272 A US 20130324026 A1 (74) Agent and/or Address for Service:

Culverstons

Dawlish Road, Wirral, Merseyside, CH61 2XP, United Kingdom (54) Title ofthe Invention: Cleanroom control system and method

Abstract Title: Cleanroom control system where the HVAC system is controlled in response to the measured particle concentration (57) A control system for controlling air volume so as to maintain a desired concentration of airborne contamination in a cleanroom. Where the cleanroom is supplied by a HVAC system 12 which supplies treated air to the cleanroom. The control system feature sensing means 48 for sensing a concentration of non-viable particles or viable particles in real time or near real time. Processing means are also provided for comparing the sensed concentration of non-viable particles or viable particles against the desired concentration of airborne contamination and outputting at least one control signal to the HVAC system 12 based on the comparison. Optionally, the processing means receives energy price data or usage data. Optionally, there is provide one or more secondary sensing means for sensing an environmental condition or process condition or HVAC system condition in real time or near real time.

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CLEANROOM CONTROL SYSTEM AND METHOD

Technical Field Of The Invention

This invention relates to a cleanroom control system and method. In particular, this invention relates to cleanroom control system which maintains the strict air cleanliness requirements of cleanrooms, whilst optimising energy performance of the equipment necessary for operations, which primarily includes the cleanroom’s heating, ventilation and air conditioning (HVAC) system.

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Background

A cleanroom is an environment, typically used in manufacturing or scientific research, that has a low level of environmental pollutants such as dust, airborne microbes, aerosol particles and chemical vapours for critical environment applications and research. More specifically, a cleanroom has a controlled level of contamination that is specified by the number of particles per cubic metre at a specified particle size. To put this in some perspective, the ambient outside air in a typical urban environment contains 35,000,000 particles per cubic metre having a particle diameter greater than 0.5pm. This would be classified as an International Standards Organization (ISO) 14644-1 Class 9 cleanroom.

For the most critical environment applications, an ISO Class 1 cleanroom allows no particles in that size range, and only 12 particles per cubic metre of 0.3pm diameter and smaller.

The majority of cleanrooms that have been designed since the 1950s are based on a fixed air volume system that are generally over-designed to supply more air than is required to meet the relevant classification and cover the risk of not maintaining the classification due to lack of continuous information. Whilst cleanroom clothing and standard operating procedures have improved greatly since the inception of cleanrooms, comparable advances in control systems have hitherto not been made.

This results in much higher energy costs than is actually needed for operating the cleanroom. There is a strong commercial need for a control system which maintains the strict air cleanliness requirements of the cleanroom, whilst optimising the energy performance of the cleanroom’s HVAC system. Any such control system which addresses this problem serves two major purposes: firstly, helping to reduce the energy costs of the cleanroom, and secondly helping companies adopt a more sustainable stance boosting their public image.

Energy efficiency activities are still few in cleanrooms, however they present a very real opportunity in terms of energy savings. The energy requirements of cleanrooms are immense: up to 80% of the energy consumed is required by the HVAC system to control temperature and humidity as well as to filter out particles and maintain pressure control. The integrity of the cleanroom environment is also dependent upon maintaining the io positive pressure created by the HVAC system.

Until recently, energy efficiency has been of little concern to cleanroom operations as energy prices were low. As Good Manufacturing Practice (GMP) compliance is of the utmost importance, most companies had been willing to accept whatever energy is required to maintain the HVAC system performance and ensure resulting compliance. This has made it hitherto difficult for cleanroom operators to reduce energy costs in HVAC systems.

It is estimated that high technology manufacturers in the UK alone spend £200 million on energy for their cleanroom operations and very few pharma cleanroom operations have any mitigation in place to reduce HVAC energy consumption. However, with rising energy prices, and a desire for more sustainable products, plant operators are very keen on finding ways to reduce energy consumption without sacrificing plant performance.

Several strategies have already been proposed for the control of HVAC cleanroom systems. Existing control systems are frequently independent of each other and are dedicated to subsystems or groups of subsystems for example: ventilation, heating and cooling, humidification and pressurisation.

One of the HVAC control systems available in the art is described in US 2013/0324026 Al. US 2013/0324026 Al provides a cleanroom control system and method that reduces the energy consumed by the air handling system of the cleanroom at times when the cleanroom was not in use. It also provides a cleanroom control system and method that enables the air handling system of the cleanroom to return to an operation state (where the air handling system operates at full capacity) from a low or reduced state upon demand or at predetermined times.

There are still problems with known control systems of this type. They do not provide the aforementioned control and flexibility to maintain cleanroom integrity and significantly reduce energy costs.

It is an object of the present invention to provide a cleanroom control system and its method of use which overcomes or reduces the drawbacks associated with known to products of this type. The present invention provides cleanroom control system that can be used with, or retrofitted to, a HVAC cleanroom system, which can save 50% or more of a cleanroom’s energy costs whilst maintaining the desired air quality levels. It is an object of the present invention to provide a control system that integrates all of the cleanroom’s operations, including ventilation, heating, cooling, room pressure, filtration.

Complex algorithms have been developed to take into account cleanroom usage, demand and user activities and/or energy prices. The present invention being able to self-adapt to maintain the area or zone of the cleanroom in the required condition in the most energy efficient and cost effective manner. It is a further object of the present invention to provide a cleanroom control system that will continuously capture, and act upon, data from airborne counters, temperature/humidity sensors, differential pressure sensors, room pressure sensors and airborne molecular contamination (AMC) sensors. Use of the present invention enabling communication, integration and/or interoperability with other third party products, including existing building management systems (BMS). The present invention using open standards and application programming interface (API) for communication. By using predictive control, variables such as occupancy, energy prices, past monitoring and usage data can be utilised to create usage patterns and forecasts for predictive control. This is key to accelerate the system response time and guarantee air quality. Use of the present invention provides a flexible, modular and scalable system which can be suitable for retrofit installation. The control system being flexible enough to be expanded upon or altered as the cleanroom environment changes.

Summary Of The Invention

The present invention is described herein and in the claims.

According to the present invention there is provided a control system for controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising:

sensing means for sensing a concentration of non-viable particles and/or viable particles in real time or near real time; and processing means for comparing the sensed concentration of non-viable particles and/or viable particles against the desired concentration of airborne contamination and outputting at least one control signal to the HVAC system based on the comparison.

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An advantage of the present invention is that it can be used to maintain the cleanroom in the required condition in the most energy efficient and cost effective manner both inoperation and at rest.

Preferably, the cleanroom further comprises one or more zones or rooms, each of the zones or rooms having a respective desired concentration of airborne contamination.

Further preferably, the desired concentration of airborne contamination is specified by the number of non-viable particles per cubic metre having a particle size of 0.1 pm,

0.2pm, 0.3pm, 0.5pm, 1pm and 5pm.

In use, the desired concentration of airborne contamination may be specified by International Standards Organization 14644-1.

Further preferably, the control system will detect movement and automatically change from an “at rest” to an “in-operation” classification or mode of operation.

Preferably, the HVAC system comprises at least one HVAC air handling unit supplying treated air through a ducting, and one or more constant air volume devices and/or one or more variable air volume devices positioned in the ducting and generally associated with each respective zone or room of the cleanroom.

Further preferably, the air treatment is selected from the group consisting, but not limited to, any one of the following: filtration, ventilation, heating, cooling, humidification, pressurisation, occupancy, and combinations thereof.

In use, the sensing means may comprise one or more ISO 14644-1 calibrated laser particle counters and/or viable particulate air monitoring sensors positioned in the cleanroom or the ducting of the HVAC system.

Preferably, the control system further comprising one or more secondary sensing means to for sensing an environmental condition and/or process condition and/or HVAC system condition in real time or near real time.

Further preferably, the secondary sensing means further comprises one or more sensors selected from the group consisting, but not limited to, any one of the following:

temperature sensor, humidity sensor, pressure sensor, differential pressure sensor, airborne molecular contamination sensor, air flow sensor, proximity sensor, and combinations thereof.

In use, the processing means may receive energy price data and/or usage data.

Preferably, the processing means receiving the sensed environmental condition and/or process condition and/or HVAC system condition and/or energy price data and/or usage data and outputting one or more secondary control signals to the HVAC system.

Further preferably, the one or more secondary control signals are outputted without causing the sensed concentration of non-viable particles to depart from the desired concentration of airborne contamination.

In use, the desired concentration of airborne contamination and/or energy price data and/or usage data may be initially user configurable.

Preferably, the at least one control signal to the HVAC system controlling the air volume supplied to the cleanroom.

Further preferably, the one or more secondary control signals controlling the filtration, ventilation, heating, cooling, humidification, pressurisation, occupancy, and combinations thereof supplied to the cleanroom.

Preferably, indication will be provided within the cleanroom through a traffic light system to indicate status. A graphical user interface may also be provided.

In use, the processing means may comprise a model predictive control algorithm.

io Preferably, the model predictive control algorithm being able to self-adapt.

Further preferably, the control system further comprising display means.

In use, the control system may further comprise means for enabling communication and/or integration and/or interoperability with third party building management systems.

Preferably, the control system further comprising for monitoring the energy performance of the cleanroom and/or performance to the ISO classification of the cleanroom.

Also according to the present invention there is provided a method of controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising the steps of:

sensing a concentration of non-viable particles and/or viable particles in real time or near real time;

comparing the sensed concentration of non-viable particles and/or viable particles against the desired concentration of airborne contamination; and outputting at least one control signal to the HVAC system based on the comparison.

Further according to the present invention there is provided a computer program product for controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising:

computer program means for sensing a concentration of non-viable particles and/or viable particles in real time or near real time;

computer program means for comparing the sensed concentration of non-viable particles and/or viable particles against the desired concentration of airborne contamination; and computer program means for outputting at least one control signal to the HVAC system based on the comparison.

It is believed that a cleanroom control system and its method of use in accordance with io the present invention at least addresses the problems outlined above.

It will be obvious to those skilled in the art that variations of the present invention are possible and it is intended that the present invention may be used other than as specifically described herein.

Brief Description Of The Dra wings

The present invention will now be described by way of example only, and with reference to the accompanying drawings, in which:

Figure lisa schematic illustration of a typical cleanroom in which the control system of the present invention is used to monitor and maintain the air cleanliness and other controlled variables including temperature, humidity, occupancy, pressure etc.;

Figure 2 shows a schematic illustration of how the control system of the present invention can be utilised to maintain the required air cleanliness of a cleanroom; and

Figure 3 is a high level flow diagram showing the multivariable inputs and outputs of the control system of the present invention.

o Detailed Description Of The Preferred Embodiments

The present invention has adopted the approach of utilising a cleanroom control system that can be used with, or retrofitted to, a HVAC cleanroom system, which can save 50% or more of a cleanroom’s energy costs whilst maintaining the desired air quality levels.

Advantageously, the present invention provides a control system that integrates all of the cleanroom’s operations, including ventilation, heating, cooling, room pressure, filtration. Complex algorithms have been developed to take into account cleanroom usage, demand and user activities and/or energy prices. The present invention being able to self-adapt to maintain the area or zone of the cleanroom in the required condition in the most energy efficient and cost effective manner. Further advantageously, the present invention provides a cleanroom control system that will continuously capture, and act upon, data from airborne counters, temperature/humidity sensors, differential pressure sensors, room pressure sensors and airborne molecular contamination (AMC) sensors. Use of the present invention enabling communication, integration and/or interoperability with other third party products, including existing building management systems (BMS). The present invention using open standards and application programming interface (API) for communication. Further advantageously, by using predictive control, variables such as occupancy, energy prices, past monitoring and usage data can be utilised to create usage patterns and forecasts for predictive control. This is key to accelerate the system response time and guarantee air quality. Further advantageously, use of the present invention provides a flexible, modular and scalable system which can be suitable for retrofit installation. The control system being flexible enough to be expanded upon or altered as the cleanroom environment changes.

Referring now to the drawings, Figure 1 is illustrative of a typical cleanroom 100 for which the control system 10 of the present invention can be utilised to maintain the required air cleanliness. The cleanroom 100 shown in Figure 1 is for illustrative purposes only and the control system 10 of the present invention can be used to control multiple zones or rooms in multiple configurations according to the requirements of the facility.

As can be seen a typical cleanroom 100 comprises a number of zones or rooms usually of varying ISO classifications. The cleanroom 100 in the example of Figure 1 has its highest rated zone or room, in this case zone 108, which is an ISO Class 5 cleanroom at the furthest point from the main door entry 110. It is adjoined to a “dirtier” cleanliness classification room or zone 104, which in this example is an ISO Class 7 cleanroom, via a gown/ungown room 106. Entry to room 104 being made through airlock entry 102.

The skilled person will appreciate that the ISO Class 5 cleanroom is kept at a higher air pressure (known as a “pressure cascade”) to prevent contaminants from, say, the adjacent

ISO Class 7 cleanroom 104 entering through the gown/ungown room 106. This pressure differential is maintained by the supply of filtered and conditioned air, which flows through the inflows 112. Exfiltration/exhaust air is taken from outflows 114. The inflows 112 and outflows 114 are controlled by the HVAC cleanroom control system 10, as described in more detail below.

Figure 2 shows how a HVAC cleanroom system can be controlled utilising the control unit or system 10 of the present invention. In order to aid clarification, only a single central HVAC air handling unit (AHU) 12 is depicted, although the skilled person will appreciate that any number of such HVAC air handling units 12 can be controlled by the control unit 10 according to the size, capacity and/or cleanliness requirements of the cleanroom 100.

As shown in Figure 2, fresh air is drawn through the inlet 14 of the air handling unit 12.

This is controlled by a series of baffles 16. The incoming air can be mixed with the air returning from the cleanroom 100 generally in the mixing area 18 behind the baffles 16. If needed, returning air from the cleanroom 100 can be directly vented outside of the air handling unit 12 via discharge outlet 20.

The air is then filtered, firstly through a pre-filter 22a and a secondary filter 22b before passing through a series of heating and cooling elements 24, 26 being drawn by the main air blower 28. The output of the main air blower 28 passes through the main highefficiency particulate air (HEPA) filter element 30 before being transferred through ducting 32 to a series of proprietary constant air volume (CAV) devices 36. It is necessary to regulate the pressure variations in the air duct system 36 in order to achieve the desired airflow in the room or zones 102, 104, 106, 108. The outflow of the air into the room or zones 102, 104, 106, 108 is through distribution grilles 38.

The air to be recirculated is drawn through grilles 40 and the control unit 10 modulates a plurality of variable air volume (VAV) devices 42 before returning the exhaust air through ducting 44 and return or check valve 46.

The control unit 10 of the present invention is used to monitor and control each and every operation of the HVAC cleanroom system. As shown in Figure 2, the control unit

10, which is typically implemented as microcontroller, receives a number of sensor inputs 48 indicated generally at the left hand side of the control unit 10. The microcontroller 100 can be considered a self-contained system with a processor, memory and peripherals and can be used to control all of the cleanroom’s 100 operations, including ventilation, heating, cooling, filtration via a number of outputs indicated generally at the right hand side of the control unit 10.

For reasons of clarity in Figure 2, the skilled person will appreciate that there are a significant number of sensors and transducers which are inputted to the control unit 10.

These have been shown schematically as sensor inputs 48 in Figure 2. This drawing is a schematic diagram and, in order to aid clarification, many other circuit elements are not shown. For example, although not shown in Figure 2, the analogue signal received from any one or more of the sensors is first converted to a digital form by any suitable type of analogue-to-digital convertor (ADC) available in the art. Equally, one or more of the digital outputs of the microprocessor 100 can be converted to analogue form using any form of digital-to-analogue convertor (DAC) available in the art. For example, such an analogue output signal could be used to energise the heating element 24. In operation, a set of instructions or algorithm written in software in the microcontroller is configured to program the control unit 10. The control unit 10 processes the input signals using complex algorithms to provide control outputs to multiple HVAC devices, including the central HVAC air handling unit 12, constant air volume devices 36 and variable air volume 42 devices to maintain a supply of filtered and conditioned air within the cleanroom 100, whilst taking into account cleanroom classification, usage and occupancy, and other activities within the cleanroom 100 environment.

The control unit 10 provides predictive sensor-based dynamic control of the HVAC cleanroom system to maintain the required air cleanliness while maximising energy efficiency. The unit 10 is a modular, retrofit control solution, easily expanded as the cleanroom 100 environment changes. It is able to communicate with third-party products for complete integration with, for example, a building energy management system.

Bespoke control algorithms have been developed based on real-world cleanroom applications in the applicant’s own HVAC cleanroom test facility.

The present invention at its core intelligently handles particulate levels in the cleanroom 100 by monitoring viable and/or non-viable particles. The control system 10 controls air volume to maintain below a desired concentration of both viable (particles containing living micro-organisms) and non-viable (particles that do not contain living micro5 organisms but acts as transportation for viable particles) particles using real time or near real time viable and non-viable particle counters, and other sensors and transducers inputted to the control system. The control system 10 being able to vary the control signal outputted to the HVAC cleanroom system as a percentage under the desired class limit as a variable set point or weighting. The control system 10 will also detect occupancy within the cleanroom 100 environment to determine the particulate limit being controlled between an “at rest” or “in-operation” mode of operation.

Figure 3 shows systematically how the control steps of the unit 10 are followed using the logic flow shown in Figure 3. In the following description each step of Figure 3 will be referred to as “S” followed by a step number, e.g. S52, S54 etc.

Figure 3 also shows that the control unit 10 can be implemented as part of, or integrated within, a building management system 50 which is computer-based control system installed in buildings that controls and monitors the building’s mechanical and electrical equipment such as ventilation, lighting, power systems, fire systems, and security systems.

In its broadest sense the control system 10 of the present invention will monitor, process and control all variables, including particulate sensors, on a continuous real time basis to ensure the HVAC equipment responds to demands, occupancy and changes within the cleanroom 100 environment and other associated areas served by the HVAC cleanroom system. The control system 10 will either control the air volume as a secondary function to maintain a correct air temperature and/or humidity directly or send and receive data to the existing BMS system 50, as required.

The sensor and control arrangement of the present invention is such that it provides a level of redundancy to ensure fail safe operation of HVAC equipment in the event of sensor failure or control system failure. In use, the sensor arrangement continuously captures data from the cleanroom 100 environment (including particulate count, temperature, humidity, occupancy, pressure) and sends that data in real time to the control unit 10 for processing. These “fail safe” modes of operation will ensure that the control unit 10 maximises the risk to the product in the cleanroom 100.

In a preferred embodiment, the control system 10 will be installed with a control panel (not shown) local to the cleanroom 100. There will be an option for a touchscreen graphical user interface on the control panel. The external devices, such as the various sensors, CAVs 36, VAVs 42 and AHUs 12 will be hardwired directly to the control system 10, although the system 10 will be able to control existing HVAC equipment via to an Open Platform Communications (OPC) server an existing BMS system 50. In addition, one or more of the various sensor inputs 48 which are remote to the control unit 10 can be inputted via wireless communication protocols, such as, for example, Wi-Fi (IEEE 802.11 standard), Bluetooth or a cellular telecommunications network would also be appropriate.

The BMS 50 or control panel of the control unit 10 can be used to set the reference inputs for the rooms or zones of the cleanroom 100. These will include the temperature and humidity and the desired cleanroom classification for the various zones. The cleanroom classifications for particulates are defined in ISO 14644, but the skilled person will understand that all classifications will be selectable or programmable in the software. The amount of air supplied to meet the cleanroom classification within a desired level of margin or comfort is also a selectable parameter, and will need to be a risked-based decision by each particular plant or facility operator.

In addition to the particulate contamination level or class, the pressure cascade within the cleanroom 100 needs to be maintained to achieve the desired cascade based on the room classifications and adjacent rooms. This will be a selectable and controllable parameter as part of the control system 10.

Once the various input variables have been initially set, the cleanroom control system 10 will continuously capture, and act upon, data from airborne counters, temperature/humidity sensors etc. and be able to self-adapt to maintain the area or zone of the cleanroom 100 in the required condition in the most energy efficient and cost effective manner.

At S52, the primary sensor input inputted to the control system 10 to maintain the area or zone of the cleanroom 100 in the required condition or class is the real time continuous monitoring of non-viable particles detected in the various rooms or zones of the cleanroom 100 or the extraction ducting 44. The particles that will primarily be the control measure will be non-viable, in the size range of 0.1 pm, 0.2 pm, 0.3 pm, 0.5pm, 1 pm and 5 pm diameter, but any particle size measurable by a particle counter could be selected as the primary control measure. Non-viable particles in the size range of 0.5 pm and 5 pm are the preferred particulates used for pharmaceutical cleanrooms 100.

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The control system 10 will also be able to monitor viable particulates using one or more viable particulate counting devices. The non-viable and viable particle counters are positioned in the room space or within the extraction ductwork 44 serving the controlled zone in the cleanroom 100.

The predictive control algorithm will follow the required particle counting methodology defined by ISO 14644, but will also be configurable to other standards and requirements. The measuring device will be a calibrated instrument, as defined in ISO 14644.

Non-viable particles are inert particles of varying sizes. Particle sizes for classifying cleanrooms are 0.1 pm, 0.2 pm, 0.3 pm, 0.5pm, 1 pm to 5pm. The measurement of these non-viable particles in the size range 0.5pm to 5pm will be the primary control measure of the control system 10. Other particle sizes can be selectable should they be required.

Viable particles are those that could carry pathogens and bacteria. The control system 10 is capable of controlling the ventilation rates to viable counts utilising appropriate viable particle counting equipment. This will be the secondary control function or measure for the control of the cleanroom 100.

The control system 100 will also need to be capable of controlling the air volume as a secondary function to maintain a correct air temperature and/or humidity. This could be measured via a connected temperature/humidity sensor, but could also be via the remote BMS 50. As mentioned, temperature and humidity are a secondary control function either measured via connected sensors or via the external BMS 50 input.

At S52, the AHU 12 also can be monitored with equipment sensors measuring pressure, temperature, humidity, power, filter pressure etc. and which are all measured as secondary input parameters but that are still part of the control unit sensor input. Each of these variables forming a part of the multivariable control system.

At S54, the various input sensors are continuously interrogated to ensure that the rooms or zone of the cleanroom 100 are within the bounds initially set by operator or as modified by the predictive control algorithm. As mentioned, the system 10 will be capable of controlling directly or interfacing with the BMS 50 for the following additional parameters: fan static pressure control, temperature and/or humidity.

In addition, pressure cascade between areas or zones of differing classification are a key requirement for cleanrooms 100. The control system 10 will maintain a pressure set point for each room or zone being controlled to either absolute pressure or differential pressure to the adjacent rooms. The pressure control, at S58, will be achieved with suitable proprietary pressure sensors and mechanical dampers capable of acting and stabilising quickly.

What is key to the present invention that provides advances over other continuously based sensor control of cleanrooms is that integrates all cleanroom 100 operations (ventilation, heating, cooling, filtration, pressure) in a complex control algorithm that takes into account cleanroom usage, occupancy and/or user activities. The number and complexity of the variables to monitor and control, and their constant evolution, means that the algorithm must self-adapt to keep the area in the required condition in the most energy efficient and cost effective manner.

The output response of the control system 10 is determined by the predictive control algorithm at S56. The algorithm is automatically and continuously adaptive and self30 learning in that it will process and analyse to make a predictive control action based on past environment conditions and equipment operation, in order to approach optimum cleanliness conditions and equipment performance according to the criteria defined by the facility operator.

The control algorithms embedded in the control unit 10 utilises a model predictive control (MPC) algorithm to maximise the control of the inputs and outputs. As mentioned, the control system 10 receives the data from the particle counters, pressure sensors, temperature sensors and/or any external BMS 50 signals. It is envisaged that energy prices and the data collected can also be used to create usage patterns and forecasts for predictive control. The MPC algorithm will process all parameters to provide the optimal control output whilst optimising energy performance of the equipment necessary for HVAC operations.

to At S58, the air volume will be controlled utilising proprietary CAV devices 36 and VAV devices 42 readily available in the marketplace with the required capabilities. The central HVAC air handling unit 12 can also be controlled directly from the control system 10 if required to optimise the system energy consumption and control.

The control system 10 can modulate the CAV 36, VAV 42 and AHU 12 to achieve the optimal air volumes and minimise energy consumption and will maintain the desired margin to the cleanroom 100 classification. The controller outputs at S58 alter the conditions in the cleanroom 100 and these are again continually monitored at S60, as described above.

The skilled person will appreciate that the control system 10 can also provide out of condition alarming and reporting. This can be via traffic light signals within the cleanroom 100, or local to control panel, e-mail, cellular messaging or via a remote web dashboard.

Offsite monitoring and alarming will also be available to allow the system 10 be monitored remotely. The cleanroom 100 and its energy performance can be monitored by the use of the applicant’s GSM-based remote energy monitoring systems under the trade mark MEMU™. These remote monitoring units feed information back to a dashboard and can include monitored variables such as temperature, airflow velocities, fan speeds, energy drawn, filter pressures etc. Predictive and planned maintenance and alarm conditions can all be set and accessed on the dashboard by the plant operator.

The software embedded in the control system 10 of the present invention is capable of being CRF11 Part 2 compliant. The system will be supplied complete and with a standard validation protocol to ensure that.

The system of the present invention is flexible enough to be expanded, and/or altered as the cleanroom 100 requirements change. The control system 10 is completely scalable for a single cleanroom 100 to multiple rooms or zones within multiple cleanrooms 100. Furthermore, no use of a system of this nature has ever been produced or hinted at in any printed publication of a system of the purpose generally for industrial use within existing io cleanrooms or bespoke cleanrooms and which provides advances in continuously based sensor control of cleanrooms.

The use of the letters HVAC (heating, ventilation and air conditioning) are intended to be used with their ordinary English language meaning and this is generally speaking accepted as the words heating, ventilation and air conditioning, as used previously in the document.

The invention is not intended to be limited to the details of the embodiments described herein, which are described by way of example only. Various additions and alternations may be made to the present invention without departing from the scope of the invention. For example, although particular embodiments refer to implementing the present invention as a HVAC cleanroom control system this is in no way intended to be limiting as, in use, the present invention can be used with many types of industrial environments. It will be understood that features described in relation to any particular embodiment can be featured in combination with other embodiments.

Claims

1. A control system for controlling air volume to maintain a desired concentration of

5 airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising:

sensing means for sensing a concentration of non-viable particles and/or viable particles in real time or near real time; and processing means for comparing the sensed concentration of non-viable particles io and/or viable particles against the desired concentration of airborne contamination and outputting at least one control signal to the HVAC system based on the comparison.

2. The control system as claimed in claim 1, wherein the cleanroom further comprises one or more zones or rooms, each of the zones or rooms having a respective

15 desired concentration of airborne contamination.

3. The control system as claimed in claims 1 or 2, wherein the desired concentration of airborne contamination is specified by the number of non-viable particles per cubic metre having a particle size of 0.1 pm, 0.2 pm, 0.3 pm, 0.5pm, 1 pm and 5pm.

4. The control system as claimed in any of claims 1 to 3, wherein the desired concentration of airborne contamination is specified by International Standards Organization 14644-1.

25 5. The control system as claimed in any of the preceding claims, wherein the HVAC system comprises at least one HVAC air handling unit supplying treated air through a ducting, and one or more constant air volume devices and/or one or more variable air volume devices positioned in the ducting and generally associated with each respective zone or room of the cleanroom.

6. The control system as claimed in any of the preceding claims, wherein the air treatment is selected from the group consisting, but not limited to, any one of the following: filtration, ventilation, heating, cooling, humidification, pressurisation, occupancy, and combinations thereof.

7. The control system as claimed in any of the preceding claims, wherein the sensing means comprises one or more ISO 14644-1 calibrated laser particle counters and/or viable particulate air monitoring sensors positioned in the cleanroom or the

5 ducting of the HVAC system.

8. The control system as claimed in any of the preceding claims, further comprising one or more secondary sensing means for sensing an environmental condition and/or process condition and/or HVAC system condition in real time or near real time.

io

9. The control system as claimed in claim 8, wherein the secondary sensing means further comprises one or more sensors selected from the group consisting, but not limited to, any one of the following: temperature sensor, humidity sensor, pressure sensor, differential pressure sensor, airborne molecular contamination sensor, air flow sensor,

15 proximity sensor, and combinations thereof.

10. The control system as claimed in any of the preceding claims, wherein the processing means receiving energy price data and/or usage data.

20

11. The control system as claimed in claim 10, wherein the processing means receiving the sensed environmental condition and/or process condition and/or HVAC system condition and/or energy price data and/or usage data and outputting one or more secondary control signals to the HVAC system.

25

12. The control system as claimed in claim 11, wherein the one or more secondary control signals are outputted without causing the sensed concentration of non-viable particles to depart from the desired concentration of airborne contamination.

13. The control system as claimed in any of claims 8 to 12, wherein the desired

30 concentration of airborne contamination and/or energy price data and/or usage data being initially user configurable.

14. The control system as claimed in any of the preceding claims, wherein the at least one control signal to the HVAC system controlling the air volume supplied to the cleanroom.

5 15. The control system as claimed in any of claims 8 to 13, wherein the one or more secondary control signals controlling the filtration, ventilation, heating, cooling, humidification, pressurisation, occupancy, and combinations thereof supplied to the cleanroom.

to 16. The control system as claimed in any of the preceding claims, wherein the processing means comprises a model predictive control algorithm.

17. The control system as claimed in claim 16, wherein the model predictive control algorithm being able to self-adapt.

18. The control system as claimed in any of the preceding claims, further comprising display means.

19. The control system as claimed in any of the preceding claims, further comprising

20 means for enabling communication and/or integration and/or interoperability with third party building management systems.

20. The control system as claimed in any of the preceding claims, further comprising means for monitoring the energy performance of the cleanroom and/or performance to

25 the ISO classification of the cleanroom.

21. A method of controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising the steps of:

30 sensing a concentration of non-viable particles and/or viable particles in real time or near real time;

22. A computer program product for controlling air volume to maintain a desired

5 concentration of airborne contamination in a cleanroom supplied by a HVAC system being operative to supply treated air to the cleanroom, comprising:

computer program means for comparing the sensed concentration of non-viable io particles and/or viable particles against the desired concentration of airborne contamination; and computer program means for outputting at least one control signal to the HVAC system based on the comparison.

15 23. A control system for controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom as described herein with reference to Figures 1 to 3 of the accompanying drawings.

24. A method of method of controlling air volume to maintain a desired

20 concentration of airborne contamination in a cleanroom as hereinbefore described.

25. A computer program product for controlling air volume to maintain a desired concentration of airborne contamination in a cleanroom as described herein with reference to Figures 1 to 3 of the accompanying drawings.

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