AU644585B2 - Improved zonal control of air conditioning system - Google Patents

Description

OPI DATE 26/09/90 APPLN. ID 51573 PCT AOJP DATE 25/10/90 PCT NUMBER PCT/AU90/00068 .INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 5 (11) International Publication Number: WO 90/10180 F24F 11/053, 11/00 Al (43) International Publication Date: 7 September 1990 (07.09.90) (21) International Application Number: PCT/AU90/00068 (74) Agent: TAYLOR, Paul, Robert; Level 10, 10 Barrack Street, Sydney, NSW 2000 (AU).

(22) International Filing Date: 22 February 1990 (22.02.90) (81) Designated States: AT, AT (European patent), AU, BB, BE Priority data: (European patent), BF (OAPI patent), BG, BJ (OAPI PJ 2878 22 February 1989 (22.02.89) AU patent), BR, CA, CF (OAPI patent), CG (OAPI patent), CH, CH (European patent), CM (OAPI patent), DE, DE (European patent), DK, DK (European patent), ES, (71) Applicant (for all designated States except US): VADELAS ES (European patent), FI, FR (European patent), GA PTY. LIMITED [AU/AU]; 70 Auburn Street, Wollon- (OAPI patent), GB, GB (European patent), HU, IT (Eugong, NSW 2500 ropean patent), JP, KP, KR, LK, LU, LU (European patent), MC, MG, ML (OAPI patent), MR (OAPI patent), (72) Inventors; and MW, NL, NL (European patent), NO, RO, SD, SE, SE Inventors/Applicants (for US only) JACOB, Edward, (European patent), SN (OAPI patent), SU, TD (OAPI Campbell [AU/AU]; 15 Parmenter Avenue, Corrimal, patent), TG (OAPI patent), US.

NSW 2518 SCHOBER, Kurt, Arthur [AU/AU]; 91 Bright Parade, Dapto, NSW 2530 BLAIN, Arthur, Charlton [AU/AU]; 205 Brokers Road, Mount Published Pleasant, NSW 2519 With international search report.

644585 (54) Title: IMPROVED ZONAL CONTROL OF AIR CONDITIONING SYSTEM (57) Abstract A unitary air conditioning system (Figs. 6 and 7) adapted to provide independent temperature control to a plurality of zones in a building or like installation. The air conditioning system comprises a plurality of temperature sensors one in each zone, at least one compressor a plurality of fans and a central processing unit The central processing unit (22) receives temperature signals from the temperature sensors (23) and after comparison with reference signals, adjusts the fans by adjusting the motor speed thereof. The system preferably also comprises air volume sensors (24) in each zone.

WO 90/10180 PCT/AU90/00068 1 IMPROVED ZONAL CONTROL OF AIR CONDITIONING SYSTEM The present invention relates to a centralised zonal air control system having an improved inbuilt facility for control of zonal environmental conditions within a building or like installation.

More particularly the invention relates to an air conditioning plant having means therewithin for control of zones in an air conditioned space.

Previously, the control of conditioned air delivery to a particular zone has usually been effected with the use of air gates located inside the ductwork or by remote sensors located in each zone of the air conditioned space which cause the controlling compressor or compressors to cut in or out according to a preselected zonal temperature setting.

To regulate the air flow, the said gates must be manually or motor operated with the result that achieving the required air delivery to maintain the set temperature for the zone is often a matter of chance.

Often these gates are positioned inside a duct at the junction of a large and smaller tributary duct such that they deflect some air from a major duct into a smaller duct. This often results in other zones having to sacrifice conditioned air which they can ill afford, in order to satisfy the requirements of another zone.

Continual adjustment of the air gates in the ducts can lead to unbalanced air delivery throughout the air conditioned space and also leads to difficulties in maintenance of preset temperature levels in the zones.

Unbalanced air delivery leads to increased running costs often due to the compressors running longer than necessary and, in winter, due to the unnecessary running of booster heating elements which compensate for imbalances in warm air delivery to the various zones.

In most existing air conditioning systems, as well as the gates inside the ductwork, there are outlet registers SUBSTITUTE SHEET WO 90/10180 PCT/AU90/00068 -2which allow conditioned air to exit the duct.

These registers are either at the extremities of the ductwork tentacles or they are positioned at various positions along the ductwork in the case of ductwork within the air conditioned space.

Within these registers there are adjustable vanes which can be manually operated to adjust the air flow to the zone which the register supplies. The ability of these vanes to accurately control the air flow is poor.

As with the air gates, it is very di.fficult to achieve the required air flow to maintain the set temperature of the particular zone when adjusting the vanes. It also becomes a matter of chance or trial and error.

It is possible to measure air delivery quantities and velocities at duct outlets in existing systems, using a hand held meter however, even if a required flow can be achieved by this method, its beneficial effect on the zone, if any, will be transient as later changes in zone temperature will render tle earlier positioning of the register vanes or gates as inefficient for correct air delivery and hence, temperature control in the zone. A further problem with the gates and vanes is that they are usually located in positions which are difficult to gain access to thus making adjustment of air flow a tedious and difficult exercise. To regulate zone temperature, presently known systems also utilise a temperature sensor mounted in a suitable position within the zone.

Usually, the sensor is designed to convert temperature into an electrical impulse which either activates or deactivates the compressors and/or booster elements depending upon the zone air temperature requirements and the system configuration.

This can become a very expensive method of maintaining zone temperature as the existing sensors do not have any control over air quantity or velocity discharge from the duct register; the latter being a much cheaper means for controlling zone temperature. According WO 90/10180 PCT/AU90/00068 -3to the general prior art configuration of ducted air conditioning systems, zonal control is effected by individual solid state, electronic or pneumatic controls at a location remote from the main plant. These sensors are wired back to a main control box which adjusts the operation of the main refrigeration plant hence enabling regulation of the zonal temperature. Zonal temperature control generally is effected by the adjustment to air volume delivered to a zone and/or air temperature.

Certain prior art systems have employed microprocessor control of gate valves in air conditioning ducts which are actuated in response to sensing by remote sensors. These configurations of air conditioning systems, whilst being suitable for their purpose are expensive to install as they require work in the various zones of the air conditioned space additional to the installation of the main plant and the duct work.

Another form of air conditioning system which is currently in use is commonly known as a split system.

This generally comprises a condenser unit aA a fan cool unit which is connected to but is usually remote from the condenser unit. The fan cool unit is joined to ductwork which can have air delivery control gates. Control of the air conditioned space is generally achieved by the positioning of a temperature sensor in a selected position within the air conditioned space usually in the vicinity of the return air register. These systems are usually divided into one, two and rarely more zones within the air conditioned space but they do not optimise economics of operation due to inaccuracies created by environmental effects about the sensor.

The sensor enables control of air delivery to a particular zone by relaying signals to the compressors in the said condenser unit.

According to the present invention the individual fan segments of the air conditioning unit are mutually exclusive so as to control each zone dedicated to its corresponding fan unit. This results in a capacity within* -4the unit to cool and heat different zones at the same time where necessary by reverse cycle operation.

The present invention also seeks to provide an air conditioning system whereby the facility for zonal control of the air conditioned space may be located at or in the central control plant.

It has not hitherto previously been known to provide a unitary package air conditioner having therewithin a capacity to regulate and maintain temperatures in multiple remote zones thereby eliminating many or all of the disadvaptages of the prior art zonal control methods.

In one broad form, the present invention provides: a unitary air conditioning system for providing independent temperature control to each of a plurality of zones in a building structure serviced by the system comprising: a plurality of speed-adjustable air supply fans to supply air to said zones, each fan being associated with a respective one of said zones; conditioning means to condition said air including heating or cooling the air; control means including a central processing unit; and temperature sensors in each zone; the control means comparing a sensed temperature in each zone with a predetermined zone temperature reference, the control means independently controlling the speed of operation of each fan to cause a variation of fan speed as required to increase or decrease the air volume to the respective zone so that the sensed temperature is increased or decreased to match the predetermined reference temperature, the control means further modulating operation of the conditioning means to vary the output thereof.

In a preferred form, the present invention provides an air conditioning system further comprising: air volume sensor in each of said zones; and said control means independently controls the speed of operation of each fan to maintain the air volume for each zone within a predetermined range whilst modulating the operation of the conditioning TJH:PP:#14075.SPC 20 October 1993 means to maintain predetermined temperature.

Preferably, in the air conditioning system of the present invention said central processing unit further automatically modulates the refrigeration and/or heating capacity of the refrigerator/heat exchanger unit in response to the signals received from said temperature sensors and/or said air volume sensors.

Also preferably, the present invention provides a system further comprising a waste heat recovery and storage system to provide supplementary heat or re-heat to any of said zones responsive to the heating and/or cooling requirements of said building structure.

Optionally, the air conditioning system is embodied wherein said waste heat recovery and storage system provides pre-heating for a conventional hot water service.

A preferred implementation of the air conditioning system of the present invention provides said central processing unit with a modem for connection to a monitor, a personal computer or centralised computer system, whereby an operator may monitor and/or control the operation of said air conditioning system.

The air conditioning system of the present invention is also preferably implemented wherein said central processing system is provided with memory to store past history details such that system operation and diagnostic data is available for analysis.

The invention will now be described in more detail according to a preferred but non-limiting embodiment and with reference to the accompanying illustrations wherein: Figure 1 shows a plan view of the condenser unit TJH:PP:#14075.SPC 20 October 1993 WO 90/10180 PCT/AU90/00068 6 according to a preferred embodiment of the invention; Figure 2 shows a side elevational view of the unit of Figure 1; Figure 3 shows an end elevational view of the compressor end of the air conditioning unit; Figure 4 shows a side view of the air conditioning unit on the return air side; Figure 5 shows an end view of the air conditioning unit from the fan end; Figure 6 shows a schematic diagram of a typical refrigeration circuit for the unitary air conditioning system of the present invention; and, Figure 7 shows a block diagram representation of the central processing unit functions, inputs and outputs.

Referring to Figure 1 there is shown a plan view of a air conditioning unit 1 according to a preferred embodiment of the invention. The unit essentially comprises an outer casing or housing 2, at least one fan assembly 3, at least one compressor unit 4 and an evaporator Although the air conditioning unit is illustrated with six fan assemblies and two compressors, the unit may be assembled with one or more fan assemblies and one or more compressors according to requirements. The compressor/s 4 are conventional compressors, likewise the evaporator/s 5. Each one fan in the battery of fan units 3 is controlled individually and operate individually to control a predetermined zone in response to zonal conditions. The fan units are fed with either fresh air or return air from a common return air duct in the direction of arrow 6 (see figure According to one embodiment the return air is drawn into each zone fan depending upon zonal requirements. Temperature sensors in each zone sense the zonal temperature and transmit a corresponding signal to a microprocessor which is pre programmed to effect a comparison between preset zonal temperature and actual zonal temperature. Where there is a differential between these two values the microprocessor WO 90/10180 PCT/AU90/00068 -7 will activate the fan for the respective zone to redress the air imbalance. The imbalance may be redressed by adjusting fan speed which in turn regulates air volume delivery to the zone or alternatively, by adjusting the temperature of the air by reverse cycle.

A microprocessor or mini computer facility within the machine is capable of directing the zonal control. Once programmed, the machine is capable of virtually automatic control of conditioned air.

Previously, in large air conditioned spaces where zones are divided by imaginary lines, problems have occured whereby one zone temperature sensor may interfere with or override the sensor of an adjacent zone not divided by a physical barrier (such as a wall), due to the effect that the air from one zone may have on the sensor of another zone.

The main air conditioning plant, in trying to accommodate the demands of both sensors has unnecessary loads placed on it which can increase power consumption.

Controlling of air flow to regulate the air temperature of a zone by using the present invention will reduce cost as the dependence upon temperature sensors to control compressors and/or heating elements to regulate zone air temperature will be reduced or eliminated.

Essentially fan speed (variable air flow) will play the major role in zonal control.

In a large building with an extensive air conditioning system it is envisaged that many fan control units could be employed depending upon the number of zones needed in the system.

The zones can be individual rooms or offices or they can be sections of larger areas.

The present invention precludes the need for peripheral booster heating in the ducts, as is used in prior art systems, due to the combined compressor and/or air delivery control all of which takes place in the one unit.

The variable speed motors which drive the fans take WO4 90/10180 PCY/AU90/00068 8 the place of the previously used variable air volume units which regulate air volume to each zone and are individually installed in the ceiling spaces above the zone being served.

The compressor/s used in this system are multistage and multispeed and are controlled by a specially designed micro-processor (not shown). The unit is intended to operate withii its own internal electronic system for control logic for any combination of zone and variable air volume and cooling heating requirement.

One major advantage of the present system is the efficiency and economies which have been enabled in the installation and operation of systems by the elimination of external ancillary apparatus at peripheries which have been previously installed and used to control air volume and temperature.

Figures 3, 4 and 5 show an end, side and oppos3ite end elevational views respectively.

Variable speed motors 7 are shown in Figure 5 and it is these motors which effectively create the zonal control in response to sensor signal transfer to the microprocessor.

Figure 6 illustrates a typical refrigeration circuit for a reverse cycle multiple zone variable air volume air cooled unitary air conditioner, in accordance with the present invention. The figure illustrates a plurality of fans 8, in this case eight fans being shown, being adapted to provide eight different zones in the building or like installation with the conditioned air, responsive to temperature sensors and/or air volume sensors provided within the zones. The zonal conditions, representing one of the signal received from the temperature and/or air volume sensors are provided into a central processing unit, for comparison of the temperatures and air volumes with reference levels previously set by an operator. The central processing unit will be described hereinafter with reference to Figure 7. Therefore, in response to the temperature and/or air volume conditions within a WO 90/10180 PCT/AU90/00068 9 particular zone, a particular fan is adapted to be controlled by the computer, such that the fan motor speed varies the amount of air which is supplied from the heat exchanger unit, represented by the numeral 9 in Fig. 6.

The other main components in the typical refrigeration circuit of Fig. 6 include an optional waste heat recovery storage unit 10, a pair of refrigerant compressors of variable speed 11, a discharge gas oil separator 12, connected to the compressors by the hot gas refrigerant line 14 the output thereof also connected to the return oil vessel 13, a refrigerant reversing valve 15, connected to a suction accumulator 16 via a return vapour refrigerant line 17. The suction accumulator 16 is also connected to the compressors 11 via return vapour contamination controls 18. The return oil vessel 13 is also connected via an outdoor refrigerant/air heat exchanger 19 which is then connected via a bi-flow liquid drier 20 to the refrigerant expansion control system 21, which consequently controls the indoor refrigerant air heat exchanger 9.

In Figure 7 is shown an electrical/electronic block diagram of the air conditioning control system in accordance with the present invention. The computer, generally designated by the numeral 22 has a number of modules preferably provided therein, including a variable speed fan output, a synchronisation logic circuit, a computer module, a power supply, and a time date function unit. A number of software modules are also preferably provided in the computer, including software to operate the variable speed fan loops, an input output module, a logic processor, a diagnostic package, communications packages, and networking packages. As illustrated in Fig.

7, the computer is preferably connected to a plurality of zone reference/feedback circuits, including temperature sensors 23, pressure transmitters and/or air volume sensors 24. The reference inputs are also inputted to the computer 22 via bus 25. Optionally, a diagnostic display keyboard 26, a diagnostic thermal printer 27 and/or a WO 90/10180 PCT/AU90/00068 10 modem 28 are also preferably inputted to the computer 22.

On the output side of the computer 22 is provided a plurality of variable speed air supply fans 29, status output signals via bus 30, a plurality of compressors 31, preferably multistage and multispeed, a waste heat recovery unit 32, and a waste heat re-heat control unit 33. A network bus 34 may optionally be provided to other units, and in air cooled models, rather than water cooled models of air conditioning systems, condensor fans 35 may also be provided.

It will be understood that the computer as illustrated in Fig. 7 is interrelated with the remainder of the refrigeration circuit as illustrated in Fig. 6, however, for diagramatic simplicity of the illustrations, the computer, and its associated inputs and outputs have been segregated from the circuit shown in Fig. 6.

It will be understood that the present invention has a number of distinct advantages over prior art air conditioning systems. Due to it's unique provision of an inbuilt multiple zone variable volume system, the requirement for site installation of zone variable air volume units in ceiling spaces is removed. The central processing unit of the present invention provides a highly intelligent level of control and monitoring data, removing the need for separate air conditioning or building management control systems. An offshoot of the present invention, which is adventageous in present day society, is the provision of a continuous waste heat recovery system during both heating and cooling cycles this can provide pre-heating of domestic portable water supplies, or other conventional water supply units.

The present invention therefore provides an air conditioning system, which, due to the incorporation of a highly sophisticated central processing unit which analyses conditions within each zone area and controls the temperature and air volume to each zone individually, depending on demand requirements, provides a number of distinct advantages over presently known air conditicning WO 90/10180 PCT/AU90/00068 11 systems. The central processing unit, in monitoring the zone conditions, automatically rmodulates the refrigeration and heating capacity to the various zone or zones and adjusts the compressor capacity to deliver only the required cooling or heating capacity thereby dramatically reducing the operating costs of the air conditioning system.

The air conditioning unit in accordance with the present invention is a high quality technologically advanced air conditioner which can provide cooling, de-humidification, heating and circulation of air for comfort and industrial applications. It is extremely o;.-mpact and is capable of serving from one to a plurality of zones, with each zone receiving the benefit of independent temperature control with fixed air quantity, or, alternatively, independent temperature control with variable air volume dependent on the requirement of the building and the air conditioning applications engineer.

The units preferably operate as a direct expansion R22 refrigeration system designed for reverse cycle/heat pump operation with the added facility that a waste heat recovery and storage system is incorporated to provide supplementary qlaat or re-heat to any zone or zones, depending on the cooling or heating requirements of a given building. As mentioned, the waste heat recovery and storage facility can optionally provide pre-heating for domestic hot water services.

The air conditioning units also incorporate the facility for any zone or zones in a multiple zone unit to operate on a fixed air quantity, with the remaining zones operating on variable air quantity.

Capacity variation of the refrigeration system is accomplished by the use of variable capacity, hermatic compressors operating in a multiplex direct expansion system. This allows for the indoor and outdoor heat exchangers to operate on either heating or cooling duty providing waste heat recovery and re-heat for any zone or zones requiring heating input to balance conditions whilst WO 90/10180 PCT/AU90/00068 12 the system is operating in cooling mode.

The function of control of the air conditioning unit is accomplished through the incorporation of a highly sophisticated central processing unit which analyses conditions within each zone area and controls the temperature and air volume to each zoi.e individually depending on demand requirements.

The central processing unit in monitoring the zone conditions automatically modulates the refrigeration and heating capacity to the various zone or zones, and adjusts the compressor capacity to deliver only the required cooling or heating capacity thereby dramatically reducing the operating costs of the air conditioning system.

The central processing unit also provides the facility for modem monitoring of the total building and system operation back to a centralised computer with the building or in the manufacturer's/consulting engineer's offices. This results in a reduction in nuisance service calls as should a complaint from a particular area be made regarding conditions this can be monitored and assessed by an engineer in the consultant or manufacturer's office before service personnel are sent to check the equipment.

As the monitoring is of high level, with individual fault and system operation data being passed back to the local or remote should a fault exist in the unit, this is analysed before the service personnel arrives at the scene.

The units can be supplied in either air coo5lu or water cooled configuration which provides a higher degree of installation flexibility of the equipments.

The integrated central processing unit in the unit also has the capability of past history diagno tics and print out of system operation and diagnostic data through the interfacng of a thermal printer.

It will be understood by persons skilled in the art that numerous variations and modifications are envisaged to the present invention. Such variations and modifications should be considered to fall within the scope of the present invention as defined hereinafter.

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Claims (6)

1. A unitary air conditioning system for providing independent temperature control to each of a plurality of zones in a build19- structure serviced by the system comprising: a plurality of speed-adjustable air supply fans to supply air to said zones, each fan being associated with a respective one of said zones; conditioning means to condition said air, including heating or cooling the air; control means including a central processing unit; and temperature sensors in each zone; the control means comparing a sensed temperature in each zone with a predetermined zone temperature reference, the control means independently controlling the speed of operation of each fan to cause a variation of fan speed as required to increase or decrease the air volume to the respective zone so that the sensed temperature is increased or decreased to match the predetermined reference temperature, the control means further modulating operation of the conditioning means to vary the output thereof.

2. A unitary air conditioning system as claimed in claim 1 further comprising: an air volume sensor in each of said zones; and wherein said control means independently controls the speed of operation of each fan to maintain the air volume for each zone within a predetermined range whilst modulating the operation of the conditioning means to maintain said predetermined temperature.

3. A unitary air conditioning system as claimed in claim 1 or claim 2, further comprising a waste heat recovery and storage system to provide supplementary heat or re-heat to any of said zones responsive to the heating and/or cooling requirements of said building structure.

4. A unitary air conditioning system as claimed in claim 3, wherein said waste heat recovery and storage system provides pre-heating for a conventional hot water service.

5. A unitary air conditioning system as claimed in any one of claims 1 to 4, TJH:P:#14075.SPC 20 Octber 1993

14- wherein said central processing unit is provided with a modem for connection to a monitor, a personal computer or centralised computer system, whereby an operator may monitor and/or control the operation of said air conditioning system. 6. A unitary air conditioning system as claimed in any one of claims 1 to wherein said central processing system is provided with memory to store past history details such that system operation and diagnostic data is available for analysis. 7. A unitary air conditioning system, substantially as herein described with reference to the accompanying drawings. DATED: 20 October 1993 CARTER SMITH BEADLE Patent Attorneys for the Applicant: VADELAS PTY. LIMITED TJH:PP:N14075SPC 20 October 1993