EP1479981A1

EP1479981A1 - Air handling control method

Info

Publication number: EP1479981A1
Application number: EP03405359A
Authority: EP
Inventors: Vishal Mallick; Georg Setzer
Original assignee: ABB Technology FLB AB
Current assignee: ABB Technology FLB AB
Priority date: 2003-05-22
Filing date: 2003-05-22
Publication date: 2004-11-24

Abstract

The present invention is concerned with an air handling control method and system (1) which allows to conserve energy by avoiding a constant ventilation of an intermittently used space (20), and at the same time achieve a good air quality right from the beginning of the space being occupied. Occupancy-related information is provided by an occupancy information tool (3), and converted into an expected future change in an occupancy status of the space (20). Ventilating means (2) are controlled in accordance therewith and made to start or increase power before said change actually occurs.

Description

FIELD OF THE INVENTION

The invention pertains to the field of heating, ventilation and air conditioning (HVAC) systems. It relates to an air handling control method, system and computer program as described in the preamble of claims 1, 9 and 10, respectively.

BACKGROUND OF THE INVENTION

Closed spaces within a building, such as hotel rooms, conference rooms, lecture halls, theatres, retail establishments, projection rooms, restaurants, meeting areas and so on, often are equipped with a system for heating, ventilation and air conditioning (HVAC). However, these spaces are not occupied on a constant or at least regular basis, and their occupancy rather follows a sporadic or irregular pattern with possibly rather abrupt changes in occupancy.
Constant ventilation of intermittently or sporadically used spaces with a fixed flow rate is not only a waste of energy, it also places an unnecessary burdon on the air handling units (filters, fans) of a building. To conserve energy, one approach is to use presence sensors which detect the presence of humans in a particular place and in turn are used to regulate the air flow to that place. Alternatively, an access control system directs information related to an individual passing the control system and entering a vacant room to the ventilation controller. Likewise, school or university timetables representing a discontinuous but regular occupancy pattern with weekly repetitions are used to control the ventilation of the corresponding classrooms or lecture halls.
A more sophisticated approach is to detect carbon dioxide (CO2) produced by the occupants, or a differential between inside and outside CO2 concentrations indicating the ventilation requirements, respectively. These solutions however do not take into consideration the fact that not only the consumption of oxygen and production of carbon dioxide necessitate a thorough ventilation, but that other sources of olfactory nuisance such as new furniture may be present in the room.
The aforementioned systems already do reduce unnecessary ventilation that would result if air intake is set to provide a ventilation strategy for a maximum assumed occupancy. Even in spaces with more static occupancies such as offices, CO2 and presence sensors can help optimize the distribution of high quality air at minimum energy.
The drawback of the known solutions based on real time sensors is that there is no good enough air quality at the start of the occupation and that time is spent to establish a sufficient working climate. This for instance becomes a problem in a space which more or less abruptly change to a higher occupancy level, and can lead to a lower productivity or receptivity of the people participating in an event taking place in said space.

DESCRIPTION OF THE INVENTION

It is therefore an objective of the invention to overcome the disadvantages mentioned above and to guarantee, in a space which is used in an intermittent or irregular way, a sufficient air quality during the whole time span, and in particular right from the beginning, of the space being occupied. These objectives are achieved by an air handling control method, system and program according to claims 1, 9 and 10. Further preferred embodiments are evident from the dependent patent claims.
According to the invention, an intermittent change in an occupancy status of the space and in particular the spontaneous entering of one or more persons into a meeting room, is anticipated based on information from an occupancy information tool and ventilating means responsible for supplying fresh and/or conditioned air to said space are controlled accordingly in due time preceding the anticipated change in the occupancy status. Ventilation thus starts early enough to provide a good climate to the occupants of the space right from the effective beginning of their meeting or event, without wasting capacity or energy by running the ventilating means at all times or according to a crude schedule. Equally, the ventilation power can be reduced towards the presumed end of the meeting provided that the remaining air quality does not drop too rapidly.
It is to be noted that the present invention is only concerned with ventilation and/or air conditioning purposes. Other parameters of the room climate generally do have a distinctly different reaction time and either follow a control command instantly (e.g. lights, shades), or are solely changed on a time scale of hours (e.g. room temperature).
In a preferred variant of the invention, the occupancy-related information delivered by the occupancy information tool comprises an indication as to a level of occupancy such as the number of occupants, i.e. if the space will be fully occupied or only partly. The air handling control system then controls a power level and/or a ventilation start time of the ventilating means accordingly.
Various applications may take the role of an occupancy information tool providing the necessary primary information. Any electronic agenda or calendar with entries related to a planned use of a particular space is suited. Although such an entry generally represents the intention of the person who entered the relevant indications, the control system does not merely rely on the indicated occupation times. The reaction of the control system, i.e. the ventilation power and/or start time may further take into account e.g. the number of invitees and the type of meeting, or the fact that a participant is expected to arrive early and spend the time until the start of the meeting in the space.
By way of example, an access control tool having stored the arrival time and the access rights, restricted to certain areas or spaces, of a visitor may communicate said times and rights to the control system. A hotel room booking tool or a meeting/conference room reservation tool may be interrogated by said control system and communicate arrival times of hotel guests or starting times of meetings.
In an alternative embodiment of the invention, primary information comprising data about an effective occupation of the space in the past is taken as an input for occupancy anticipation. From a known behaviour of the occupants during a past period, recorded e.g. by means of presence detection, an occupancy pattern is deduced by the air handling control system. If the system notices that at a particular time of a particular day of the week the space under consideration used to be occupied or vacant, an extrapolation based on the assumption of a similar behaviour of the users during the next week or all following weeks is done.
Obviously, the occupancy pattern may not be that simple and/or correlated to other parameters or secondary information. For such cases, more sophisticated procedures for statistical analysis, e.g. based on neural networks, are needed for determining a significant occupancy pattern.
In a further preferred variant of the invention, auxiliary sources of information apart from the occupancy information tool are consulted by the control system. By way of example, the live transmission of a popular sports event on TV may lead to an increase in the number of guests in a pub or other projection space. On the other hand, sunny weather conditions may motivate a number of people to step outside and leave their office building at lunch time, thus reducing the need for fresh air in an in-house cafeteria. The primary occupancy prediction of the aforementioned public spaces is correspondingly weighted with such secondary information provided by the TV program or the weather forecast.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the attached schematical drawings, in which:
Fig. 1 shows an air handling control system and related components.
The reference symbols used in the drawings, and their meanings, are listed in summary form in the list of reference symbols.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig.1 depicts an air handling control system 1 which is connected to a ventilating means 2 depicted by a fan and which is in fluid connection with a closed space 20 in a building to which it provides fresh air. The ventilating means 2 optionally may be coupled with an air conditioning device for cooling purposes, or may comprise dampers or may be part of a full air distribution/redirection system. Both the operation and the power of the ventilating means are controlled by the control system 1. The latter receives relevant primary information 30 from an occupancy information tool 3 and deduces the next or even all future changes in an occupancy status of the space 20. The air handling control system 1 generally comprises a processor means on which an appropriate computer program is executed and thereby produces control signals for the ventilating means 2. The occupancy information tool 3 need not be physically separated from the system 1, i.e. the memory means storing the relevant occupancy-related information may be a component of the same computer or server as the processor means of the control system 1. An additional source of information 4 provides secondary information 40 such as weather or TV program. This helps both in an analyzing process, e.g. by explaining why a particular occupancy status in the past appears to be incoherent, as well as in predicting the amplitude of forthcoming changes.
The occupancy information tool 3 may be a hotel reservation system intended for optimizing the usage of different floors, which system provides functions for booking a hotel room and stores estimated arrival times of hotel guests. An example called "starlight front office system" is provided by Hogatex (http://www.hogatex.com/iprod1 e.html). A rather straightforward deduction of occupation times of individual hotel rooms from the reservation schedule is possible.
A building access control system as a further example of an occupancy information tool is offered e.g. by Lenel Systems International Inc. and described in detail in http://www.lenel.com/onguard/index.htm. "OnGuard Visitor" provides a web browser-based application that allows companies to manage visitors and employees throughout their enterprise. Data from this application based on the knowledge of who is entering the building and at what time can be fed in the air control system 1, and the latter deduces changes in an occupancy status of the person's office room.
Still another, increasingly common application in office buildings are electronic tools for booking meetings and conference facilities (c.f. http://www.wizardwebsigns.com/). Information from these systems can equally well be converted into an expected future change in an occupancy status of the meeting or conference room. The ventilating means 2 being set to work in due time before the start of a scheduled meeting ensures an optimal ventilation right from the beginning of the event.
A computer program for controlling the ventilating means 2 according to the invention which is loadable into an internal memory of one or more digital computers, comprises computer program code means to make, when said program is loadad in the computer, execute the method as described above.

LIST OF DESIGNATIONS

1: air handling control system
2: ventilating means
20: space, room
3: occupancy information tool
30: primary information
4: auxiliary source of information
40: secondary information

Claims

An air handling control method for controlling, via a ventilating means (2), the application of fresh air to a closed space (20) undergoing intermittent changes in an occupancy status,
characterized in that a control system (1) receives primary information (30) from an occupancy information tool (3), anticipates a change in the occupancy status of the space (20) from said primary information (30) and controls the ventilating means (2) before the anticipated change in the occupancy status.
The method according to claim 1, characterized in that the primary information (30) given by the occupancy information tool (3) comprises a level of occupancy.
The method according to claim 1, characterized in that the occupancy information tool (3) is an agenda and the primary information (30) comprises individual entries in the agenda related to a planned occupancy of the space (20).
The method according to claim 3, characterized in that the agenda is a hotel room booking system, or a conference room reservation system, or an access control tool adapted for granting access rights to an announced visitor.
The method according to claim 1, wherein the occupancy information tool (3) comprises a memory means and the primary information (30) is stored on said memory means and comprises indications about past effective changes in the occupancy status of the space (20), characterized in that the system (1) proceeds to a statistical analysis of said information (30) and anticipates future changes in the occupancy status of the space (20) therefrom.
The method according to claim 5, characterized in that the statistical analysis is involves a neural network type of intelligence.
The method according to one claims 1 to 6, characterized in that the anticipation of the change in the occupancy status of the space (20) by the control system (1) takes into account secondary information (40) from an auxiliary information tool (4).
The method according to claim 7, characterized in that the secondary information (40) comprises indications about a TV-program or a weather forecast.
An air handling control system (1) for applying, by way of a ventilating means (2), fresh air to an intermittently used closed space (20) within a building,
characterized in that the control system (1) is adapted to receive primary information (30) from an occupancy information tool (3), anticipate a change in the occupancy status of the space (20) from said primary information (30) and to control the ventilating means (2) before the anticipated change in the occupancy status.
A computer program for controlling a ventilating means (2) which is loadable into an internal memory of a digital computer, comprising computer program code means to make, when said program is loaded in said internal memory, the computer execute the air handling control method according to one of claims 1 to 8.