WO1996024807A1

WO1996024807A1 - Room air quality conditioning system

Info

Publication number: WO1996024807A1
Application number: PCT/CA1996/000059
Authority: WO
Inventors: Sydney J. Becker
Original assignee: Becker Sydney J
Priority date: 1995-02-09
Filing date: 1996-01-30
Publication date: 1996-08-15
Also published as: AU4478796A

Abstract

An air quality control system is provided herein. The system includes an inflow system which includes a tubular enclosure (15) suspended from a ceiling of a room (10) or from a roof (11) above the room (10). The tubular enclosure (15) is fitted with a ceiling fan (14). An air supply unit (17) external to the room (10) (e.g., outdoors) includes an air supply duct, the air supply duct being connected to an inlet to the interior (26) of the tubular enclosure (15). The flow of air to the tubular enclosure (15) is controllably variable. An outflow system is also provided for exhausting substantially all the air volume inflowing through the inflow system. The outflow system includes an exhaust grill (30) connected to the ceiling or a wall of the room, an exhaust riser duct (31) connected to the exhaust grill (30), and an exterior exhaust outflow fan (33) connected to the outlet (34) from the exhaust riser. The exhaust fan (33) is operated in conjunction with the inflow fan to exhaust, via the outflow system, substantially all the volume of air inflowing through the air inflow system into the inside room (10) through the outflow system. In this way, the quality of air in the inside room is improved by impelling a selected volume of outdoor air downwardly into inside room air, circulating the outdoor air within the inside room and expelling that selected volume of used inside room (10) air from the inside room (10), and by allowing the occupant of the inside room (10) to adjust comfort conditions by varying air circulation and the selected volume of outdoor air.

Description

(1) Title of the Invention

Room Air Quality Conditioning System

(2) Technical Field

This invention relates to a system for introducing outdoor air to a room or space and to achieve optimum air quality conditioning of the room air by the outdoor air without creating objectionable drafts or turbulence.

(3) Background Art

The study of the subject of mechanical ventilation systems and indoor air quality has resulted in at least two publications: a European publication entitled "Ventilation For Buildings, Design Criteria For the Indoor Environment, (draft 31 Jan. 1994); and a U.S. publication entitled "ASHRAE Standard 62-1989, Ventilation For Acceptable Indoor Air Quality". Both these publications identify the requirement that the forced air circulation system should ventilate, but should not create turbulence or drafts that are uncomfortable for the occupants.

Forced air circulation systems are used in buildings occupied by humans. Such systems are used for three basic purposes, namely, heating, cooling and ventilating. Nentilation implies supplying outdoor air and removing pollution that is generated in the building by the occupants. The purpose of all this is to provide a comfortable and healthy environment. The effectiveness of a forced air circulation system in maintaining these conditions depends on how thoroughly the circulated air mixes with the space or room air, and the removal of the used air or contaminated air from the room or space.

Since people are sensitive to drafts and air temperature changes, present practice uses grills or diffusers to introduce the supply air to a space or room with the least turbulence and yet with sufficient movement and circulation to create the best mixing. The mixing is crucial, since it is the way the room or space is heated or cooled, and it is the way the contamination generated by the occupants is picked up and diluted so it can be exhausted from the room or space. However, in the use of grills or diffusers, a small temperature difference is necessary. Indoor air problems are a major health concern, and a public health problem that has enormous financial significance in all countries that have buildings that are mechanically ventilated by forced air circulation systems. This is due to the ineffective and inadequate performance of grills and diffusers in achieving thorough mixing of the introduced air and the room air.

The techniques presently in use to improve mixing in a space, are to increase the volume of air delivered to a room or space, i.e. , the number of air changes per hour. However, to avoid increasing the energy requirements, present practice is to mix outdoor air or fresh air with recirculated air, i.e., used air, but with no means for positively expelling such mixed air to the outdoors. Nevertheless, it is known that such a process reduces the quality of the supply air by ignoring a basic public health law, namely, that outdoor air should not be mixed with used air, since used air is contaminated air. It is believed that this fact contributes to the cause of what is called the Sick Building Syndrome. Thus, present practice in the air conditioning industry ignores the fact that the respiratory system is also an avenue for infection.

One way to assist in the ventilation of a room in a building has been by the use of ceiling fans. The slow moving blades stir the air enough to make persons feel comfortable.

Among the patented systems which have been provided in other attempts to assist in the ventilation of a room in a building, the following may be noted: Canadian Patent No. 832,788 patented January 27th, 1970 by A. Erfelling; Canadian Patent No. 942,572 patented February 26th, 1974 by A.Ahlberg; Canadian Patent No. 1,057,562 patented July 3, 1979 by I.C. Whiteley; Canadian Patent No. 1 ,090, 190 patented November 25 , 1980 by D.B. Rusth; Canadian Patent No . 1 ,134 , 666 patented November 2nd , 1982 by D.B. Rusth et al; U.S. Patent No. 1,296,968 patented March 11, 1919 by A. Klein; U.S. Patent No. 1,925,822 patented September 5, 1993 by W. Shurtleff; U.S. Patent No. 2, 126,230 patented August 9, 1938 by E.R. Troxell, Jr.; U.S. Patent No. 2,267,425 patented December 23rd, 1941 by W. Rowe et al; U.S. Patent No. 2,275,295 patented March

3rd, 1942 by G.H. Greenway; U.S. Patent No. 2,354,292 patented July 25, 1944 by A.E. Waterman; U.S. Patent No. 2,398,627 patented April 16, 1946 by I.R. Disbro et al; U.S. Patent No. 3,669,349 patented June 13, 1972 by W.X. Hall, Jr.; U.S. Patent No. 3,974,754 patented August 17th, 1976 by J.W. Powlesland et al; U.S. Patent No. 4,535,684 patented

August 20, 1985 by G. Perng; U.S. Patent No. 5,097,674 patented March 24, 1992 by T. Imaiida et al; and U.S. Patent No. 5,326,314 patented July 5, 1994 by J.M. Brockway et al.

The latter two patents are considered the closest prior art. U.S. Patent No. 5,097,674 teaches an air conditioning apparatus with an air conditioner embedded in a ceiling of a room provided with an air inlet port opening to the room, a heat exchanger and a blower. A duct box is connected to the air conditioner through a blow-off casing provided on the duct box to project air into the room via an air outlet opening to the room. A fan is disposed on a lower portion of the blow-off casing. A diffuser is provided for redirecting conditioning air from a vertical direction to a substantially horizontal direction. The fan includes an outer rotor motor and a plurality of blades fixedly attached to an outer peripheral surface of the outer rotor of the motor. Air within the room is continuously recirculated and the temperature may be controlled. No fresh air is introduced.

U.S. Patent No. 5, 326,314 teaches a ventilation system for proper ventilation of industrial manufacturing facilities. The system provides an exclosure within the building including the ceiling, floor and certain walls by means of an air-impervious curtain attached to the ceiling and to one or more walls, with a lower edge spaced above the floor. An air supply assembly includes ceiling mounted fans, and vertical and horizontal ductwork for forcing outside unconditioned air upwardly into the enclosure and through a discharge slot formed in the horizontal ductwork at a level spaced-above the floor. Air heating units are mounted within the building for forcing heated outdoor air into the building Such heated air and polluted air from the industrial manufacturing enter the enclosure. A plurality of ceiling mounted fans is provided for withdrawing air which is trapped within the enclosure for exhausting it into the atmosphere. A control unit is provided for controlling the air supply assembly, the air heating units and the air exhaust fans for effecting a predetermined number of air changes within the enclosure. (4) Disclosure of the Invention The systems described in the above-defined patents are deficient since they do not solve the problem of avoiding the use of contaminated air, i.e. , they all require mixing the outdoor fresh air with contaminated recirculated air.

Objects of the present invention are therefore to provide a room air circulating system which does not substantially rely on the use of recirculated air; and to provide such a system which not only ventilates a room but which can also be used for heating or cooling a room.

The present invention provides a system for improving the condition and quality of indoor air in an inside room space. The system includes an inflow system which comprises: an outdoor air supply unit including an air supply inlet port provided in an air supply discharge duct and a fan connected between the air supply inlet port and the air supply discharge duct for discharging outdoor air through the supply outlet duct; an air supply unit including an air intake connected to the air supply discharge duct, an air outlet duct, an air outflow duct, and means to control the volume of air discharged through the air outflow duct; and a tubular enclosure suspended from a ceiling of a room, the tubular enclosure including a main air inlet port connected to the air outflow duct, a discharge outlet port, and a depending ceiling fan, the tubular enclosure thereby feeding outdoor air to the vortex of the ceiling fan to discharge the outdoor air downwardly into the inside room space; and an outflow system which comprises: an exhaust grill connected to the ceiling or to a wall of the inside room adjacent the ceiling; an exhaust riser duct connected to the exhaust grill; and an exterior exhaust fan connected to the outlet from the exhaust riser duct.

In such system, the exterior exhaust fan of the outflow system being operated in conjunction with the fan of the outdoor air supply unit of the air inflow system to exhaust, via the outflow system, substantially all the volume of air inflowing through the air inflow system into the inside room through the air outflow by system. In that way, the quality of air in the inside room is improved by: impelling a selected volume of the outdoor air downwardly into the inside room air, circulating the outdoor air within the inside room and expelling the selected volume of used room air from the room, and by allowing the occupant of the inside room to adjust comfort conditions by varying air circulation and the selected volume of outdoor air.

The air supply unit can be of three alternative types: a variable air volume box having the air intake which is connected to the air supply discharge duct, the air outlet duct, the air inflow duct and the means to control the volume of air discharged through the outflow duct; that air supply duct which is connected directly to the air intake to the interior of the tubular enclosure, the flow of air to the tubular enclosure being controllably variable, and the air supply unit including a heater within the air supply duct, and controls for controlling the operation of the heater to control the air temperature; or that air supply duct which is connected directly to the air intake to the interior of the tubular enclosure, the flow of air to the tubular enclosure being controllably variable, the tubular enclosure of the air supply unit having a heater disposed transversely thereacross, which includes controls for controlling the operation at the heater to control the air temperature.

In such air quality control system: the outflow system may be situated exteriorly of the room, e.g. , on a roof of a building in which the room is located; the air supply unit includes dampers therein, and controls for controlling the dampers to adjust the volume of introduced outside air; means are provided to control the temperature of air which is admitted to the air supply unit; e.g. , a heater, especially an electric heater, and means to control the operation of the heater, e.g. , a temperature limit control switch, especially an internal air temperature limit control switch within the tubular enclosure situated downstream of the electric heater to control the operation of the electric heater; overall flow of air is controlled by dampers, which are, e.g. , operated by a motor, especially by an electric motor; and the damper is operable at a minimum air volume less than about 20 CFM per person, or is operable between a minimum air volume of about 20 CFM and a maximum air volume of about 60 CFM per person; the ceiling fan is driven by a variable speed motor, and includes controls to control the speed of the fan; especially where the ceiling fan blades project into the room adjacent to the ceiling; and more especially where the ceiling fan includes a deflection plate associated with the blades; and the outdoor air supply unit includes at least one of a filter, a heating coil, a cooling coil, a fan, and a refrigeration compressor; and optionally, all connecting duct work is insulated. In one embodiment, the present invention thus consists of a ceiling fan unit within a tubular enclosure, which is suspended from the ceiling or the roof and which is open at the bottom. The fan unit is attached to the ceiling, in the usual manner for this type of fan. For purposes of ventilation and temperature control (e.g., heating), in one embodiment, a flexible duct connects the tubular enclosure or cowling into a variable air volume (NAV) terminal box that is equipped with volume control dampers, and a suitable heater, e.g., a heating coil, which may be either electric or hydronic. Filtered air, that is cooled or heated as required by the outdoor temperatures during the different seasons and for different climates, is supplied to the VAV box by an external central air handling fan unit which may include one or more of a filter, a heating coil, a cooling coil, a fan, and a refrigeration compressor. Accordingly, as dis¬ cussed above, the device of the present invention can be used for heating or cooling a room or space by combining it with a standard VAV terminal box. Controls are provided that permit the room occupant to vary the speed of the fan, and to vary the amount of ventilation, by adjusting the volume of outdoor air that can be introduced through the VAV. The room occupant can thus control the temperature in the room in either a heating mode or a cooling mode. At all times, the supply air to the ceiling fan is fresh air (which may be cooled or heated), and the used room air is exhausted to the outside of the building.

In a second embodiment, a flexible duct is directly connected to the tubular enclosure. The tubular enclosure is equipped with volume control dampers, controlled by a damper motor. A suitable heater, e.g., an electric heating coil, is fitted within the flexible duct, and is controllable to control the temperature of the incoming air.

In a third embodiment, a flexible duct is directly connected to the tubular enclosure. The tubular enclosure is equipped with volume control dampers controlled by a damper motor, and with a transversely-mounted electric heating coil. The electric heating coil is controllable to control the temperature of the air within the tubular enclosure.

In the second embodiment, or in the third embodiment described above, filtered air, that is cooled or heated as required by the outdoor temperatures during the different seasons and for different climates, is supplied directly to the tubular enclosure by an external central air handling fan unit which may include one or more of a filter, a heating coil, a cooling coil, a fan, and a refrigeration compressor.

The system of the present invention can be used for heating or cooling a room or space by combining it with the tubular enclosure as described in the second and third embodiments above. Controls are provided that permit the room occupant to vary the speed of the fan, and to vary the amount of ventilation, by adjusting the volume of outdoor air that can be introduced through the tubular enclosure. Heater temperature limit controls are provided downstream of the electric heater in both the second and third embodiments. The room occupant can thus control the temperature in the room in the heating mode (by virtue of the cooling coil in the air handling fan unit), or the cooling mode. At all times, the supply air to the ceiling fan is fresh air (which may be cooled or heated), and the used room air is exhausted to the outside of the building.

(5) Brief Description of the Drawings In the accompanying drawings, Fig. 1 is a schematic central longitudinal section through a room showing the components of the air quality control system of one embodiment of this invention;

Fig. 2 is a central longitudinal section through the ceiling fan portion of the air quality control system of one embodiment of the invention;

Fig. 3 is a bottom plan view of the view depicted in Fig. 2, showing the deflection plate;

Fig. 4 is a central longitudinal section through the ceiling fan portion of the air quality control system of a second embodiment of the invention;

Fig. 5 is a bottom plan view of the view of the second embodiment depicted in Fig. 4, showing the deflection plate;

Fig. 6 is a central longitudinal section through the ceiling fan portion of the air quality control system of a third embodiment of the invention;

Fig. 7 is a plan view of the transversely-mounted heater in the third embodiment depicted in Fig. 4, the deflection plate not being shown, since it is the same as in Fig. 5; and Fig. 8 is an isometric view of a typical arrangement showing outdoor air supply fans, incorporated with an existing conventional heating and/or cooling system. (6) Best Modes For Carrying Out the Invention

As seen in Fig. 1, a room 10 is shown having an outdoor roof 11 and/or and a suspended ceiling 12. A set of ceiling fan support brackets

13 provide the means whereby a ceiling fan unit 14 with tubular enclosure 15 may be suspended from the roof 11 and/or suspended ceiling 12 into the room 10. While not shown, other equivalent means may be provided to suspend the tubular enclosure 15 from the roof 11 and/or the ceiling 12. Further details of the fan system will be given in the description of Fig. 2.

The ceiling fan unit 14 includes fan blades 16 and a deflector plate 60. Although not shown, the fan blades 16 may be provided with wire or other guards for safety reasons where needed.

Mounted on the roof 11, or even inside the building, is a conventional air supply unit 17, provided with the usual filters, heating coil, cooling coil, fan 17a and refrigeration compressor as required by regional climatic conditions. The air supply unit 17 includes an inlet 18 and an insulated air supply outlet duct 19.

Duct 19 leads to the inlet 20 of a variable air volume box (VAV) 21, provided with dampers 22 and a heater 23, which may be electric or hydronic, and with a high temperature limit control. The outlet 24 of the variable air volume box 21 leads, via a flexible insulated air duct 25, to the interior 26 of the tubular enclosure 15 of the fan system 14.

An exhaust grill 30 is provided within the room 10 near the suspended ceiling 12. The exhaust grill 30 includes an exhaust duct 31 leading to the inlet 32 of an exhaust fan 33. The exhaust fan 33 is provided with a conventional outlet duct 34. The room 10 is provided with the usual room thermostat (T) and fan speed controls (C). In cold climates, a heater 40 may be provided to maintain a minimum temperature during freezing weather, or when the ventilation system is shut down, or when the building is not occupied. The heater 40 may be electric or hydronic. As seen in Fig. 2, an electric junction box 50 is fixed to the attachment brackets 13. Also suspended from the attachment brackets 13 is a tubular enclosure 15 having an interior 26 which is open at the bottom 26a and which extends through the suspended ceiling 12. An outdoor air supply collar 28 is fitted to the tubular enclosure 15 for connection to duct 25.

Suspended from the electric junction box 50 is a pipe 51 containing the electrical wires, the pipe 51 being connected to the fan motor 52. The fan motor 52 is secured by a spider brace 53 to the interior of the tubular enclosure 15. The fan blades 16 are driven by the fan motor 52. The fan blades 16 are provided with a deflector plate 60 (better seen in Fig. 3).

The embodiment of Figs. 4 and 5 differs from the embodiment of Figs. 1 , 2 and 3 in that a VAV box is not used. In its stead, a direct attachment is provided as follows.

As seen in Figs. 4 and 5, an electric junction box 450 is fixed to the attachment brackets 413. Also suspended from the attachment brackets 413 is a tubular enclosure 415, having an interior 426 which is open at the bottom 426a and which extends through the suspended ceiling 412. An outdoor air supply collar 428 is fitted to the tubular enclosure 426, which, as shown, is directly connected to flexible conduit 421.

Either the outdoor air supply collar 428 or the flexible conduit 421 is provided with an electric heater 422. The electric heater 422 is controlled by a heater temperature limit control 423 provided downstream thereof in the interior 426 of the tubular enclosure 415. The tubular enclosure 415 is provided with an air volume control damper 424 at the junction 425 of the outdoor air supply collar 428 and the tubular enclosure 415. A damper motor 427 is provided to control the operation of the air volume control damper 424. Suspended from the electric junction box 450 is a pipe suspension rod 451 containing the electrical wires, the pipe suspension rod 451 being connected to the fan motor 452. The fan motor 452 is secured by a spider brace 453 to the interior 426 of the tubular enclosure 415. The fan blades 416 are driven by the fan motor 452. The fan blades 416 are provided with a deflector plate 460 (better seen in Fig. 5).

The embodiment of Figs. 6 and 7 differs from the embodiment of Figs. 4 and 5 in the location of the electric heater. As seen in Fig. 6, an electric junction box 650 is fixed to the attachment brackets 613. Also suspended from the attachment brackets 613 is a tubular enclosure 615 having an interior space 626 which is open at the bottom 626a and which extends through the suspended ceiling 612. An outdoor air supply collar 628, which is connected to air supply outlet duct 619, is fitted to the tubular enclosure 615. Also shown in Fig. 6 are the fan blades 616 and the deflector plate 660.

Suspended from the electric junction box 650 is a pipe suspension rod 651 containing the electrical wires, the pipe suspension rod 451 being connected to the fan motor 652. The fan motor 652 is secured by a spider brace 653 to the interior 426 of the tubular enclosure 615. The fan blades

616 are driven by the fan motor 652. The fan blades 616 are provided with a deflector plate 660 (better seen in Fig. 7).

The tubular enclosure 615 is provided with a transversely-mounted electric heater 622. The electric heater 622 is controlled by a heater temperature limit control 623 provided downstream thereof in the tubular enclosure 615. The tubular enclosure or cowling 615 is provided with an air volume control damper 624 at the junction 625 of the outdoor air supply collar 628 and the tubular enclosure 615. A damper motor 627 is provided to control the operation of the air volume control damper 624. As seen in Fig. 8, a typical arrangement in an office 800 is depicted. The office includes a standard cooling rooftop unit 810, a standard outdoor fresh air unit 812 and a standard outdoor exhaust unit 814. The standard cooling rooftop unit 810 is connected, via lines 816 to cooling air exhaust louvres 818. The outdoor exhaust unit 814 connects to exhaust louvres 820 via lines 822. The standard outdoor fresh air unit 812 is connected to the outdoor air ceiling supply fans 824 of the present invention, i.e., 14, 452, 652, previously described, via lines 826.

The office 800 is composed of a plurality of rooms 802. Many of the rooms are provided with fan coil units 804. Louvres 818, 820 and outdoor air ceiling supply fans 824 are provided in the individual rooms 802, as required. (7) Industrial Applicability

In operation, the rotation of the ceiling fan in each room or space impels the fresh entering air downwardly through the room air. This provides an air quality conditioned space and alters the temperature of the room air so as either to heat or to cool the room or the space. Such mixed air is expelled in the same volume as the fresh introduced air. This simultaneously provides an air quality conditioned space and ventilates the room or space by dilution of the pollution generated in the room or space.

The air leaving the external air supply unit may be controlled to maintain a constant temperature which is lower than the room temperature, or the air within the tubular enclosure or cowling may be so controlled.

This temperature is suitable for cooling any space that needs cooling during the winter season, (for example, in sun-exposed rooms with large glass areas). The VAV box may have a heater to warm the air supply to maintain the temperature setting of the room thermostat. Alternatively, the flexible duct, or the tubular enclosure or the cowling may include a heater, preferably an electric heater, which may be controlled by a thermostat. Thus, if a room needs heating, the room thermostat controls the heater to provide the required temperature. The air supply temperature to each room is adjustable by the room thermostat. Consequently, by the present invention, the ventilation function is separate from the temperature function. The air volume delivered to the fan is controlled by the dampers operated, e.g. , by the above-recited motors, between two positions, i.e. , a minimum of about 20 CFM and maximum of about 60 CFM per person, but it remains constant at the minimum setting, unless the room occupant chooses to increase it. The ventilating air volume is constant at a minimum setting. The room occupant can vary the volume of ventilating air to the maximum if needed. This air volume is based on the performance of present day grills and diffusers. However, the present invention is also operable at less than about 20 CFM per person, which results in significantly less energy requirements both in summer and in winter.

The external air supply unit that supplies the fresh outdoor air may be similar to a conventional, commercially-available roof top unit, that has fans, filters, electric heating coil, refrigeration compressor with air condenser, and a cooling coil and which generally is provided with duct work connected to a VAV. The introduced fresh air then may be cooled and/ or filtered to remove dust. A similar type unit can be housed in any other part of the building. Such a unit would supply the fresh outdoor air to each of the one or more VAV boxes that supply the fresh air to the one or more ceiling fans in one or more rooms.

It is clear that the room occupant can control the air temperature and the ventilation, without affecting the ventilation effect. The controls which are provided enable the required control and flexibility needed to adjust to changing environmental conditions. This provides maximum satisfaction and maximum energy conservation.

It is known that the rate of air supply required either to heat or to cool a room that has a heat loss or heat gain varies inversely as the temperature difference between the air supply temperature and the room temperature. To avoid uncomfortable air currents from grills or diffusors, present design criteria limit the temperature difference between the supply air and the room air to 1 to 2°C. This temperature difference is critical with ceiling heights of 2.3 M or less, since in rooms with dropped (lowered) ceilings, there is more chance of occupant discomfort. With the air quality control system of the three embodiments of the present invention, which mixes the fresh air with the existing room air throughout as the fresh air is introduced, the temperature difference can be as high as 5 to 8°C with ceiling heights 2.3 M or less. Furthermore, the room occupant can control the fan speed to vary the air movement and mixing. Therefore, the air volume to heat or to cool is less with the air quality control system of the three embodiments of the present invention in the ratio of about 1/3 to about 1/5 of that required for grills or diffusors. This reduces costs and operating expenses accordingly.

In rooms with dropped (lowered) ceilings of 2.3 M height, there is more chance of occupant discomfort. Accordingly, the air quality control system of the three embodiments of the present invention is effective in landscaped offices, (with low partitions) private offices, and offices with low partitions, since it includes the combination with an air volume control and air heater control, and an external air supply unit, that has both a heating and a cooling capability. The system of the three embodiments of the present invention enables the room occupant to control the ventilation rate, and the Ventilation Effectiveness (to be defined hereinafter), which can be set by adjusting the air volume and/or the fan speed and/or the temperature. This is not possible with any other type of forced air circulation system that uses grills or diffusers. Another unique feature of the present invention is that the used, or exhaust, air is constantly ejected from the building.

In the air quality control system of the three embodiments of the present invention, the ceiling fan produces mixing instead of unpredictable discharge jets or currents from grills or diffusers. The ceiling fan mixing is positive and produces a Ventilation Effectiveness of (as defined hereinafter) 1. The fan speed can be varied to suit the variations in ventilation requirements in the room. Therefore using the air quality control system of the three embodiments of the present invention reduces the cost of the air handling system, since ducts, fans, motors, and all other related equipment cost less. Thus, another advantage of using the air quality control system of the three embodiments of the present invention is cost reduction of the installation. The energy requirements are less because the ceiling fan requires much less energy, compared to the energy required continually to move air through grills and diffusers.

The air quality control system of the three embodiments of the present invention optimizes the performance of forced air circulation systems when they are used for ventilating, cooling and heating spaces for human occupancy.

The air quality control system of the three embodiments of the present invention introduces outdoor air directly to the occupied rooms. The room occupant can control the fan speed. Used air is exhausted from the building in the same amount as the introduced fresh air. This eli i- nates the systemic contamination of supply ducts when return air is mixed with outdoor air and the mixture supplied to the rooms. This also reduces maintenance by eliminating the need to clean ducts. There are reduced maintenance expenses since only the external filter must be cleaned.

In buildings where smoking is not permitted, the device of the three embodiments of the present invention can be used for ventilating areas that are isolated for smokers. The air quality control system of the three embodiments of the present invention can be used to modify existing systems, by adding exhaust ducts where necessary without changing the supply ducts. 8) Principal Features of the Invention

The systems of this invention have the following beneficial features, namely: it does not circulate used air; it provides individual control of the ventilation rate, i.e. , the amount of outdoor air drawn in; it mixes the outdoor air thoroughly with the room air and in so doing improves the quality of the room air; and it exhausts used air from the room.

The systems of this invention are:

1) modular and provide the occupant with individual control of air movement and ventilation rate. (i.e. outdoor air);

2) do not circulate used air, and are not subject to systemic contamination;

3) circulate less air, and hence the energy requirements are a small fraction of the energy requirements for conventional air conditioning systems;

4) are suitable for retrofitting existing systems in problem buildings;

5) provide a benefit of reduced cost of installation, maintenance and operation which are less than for a conventional air conditioning system; and

6) can be shut down when a room or space is not occupied without affecting the temperature control system.

9) Ventilation Effectiveness

The term for the process of diluting the pollution is called "Ventilation Effectiveness" or "contaminant removal effectiveness". It is measured by comparing a) the pollution concentration in the exhaust air from the room and b) the pollution concentration in the air at the breathing level. If they [i.e., a) and b)] are the same, the ventilation effectiveness is one. If the concentration at the breathing level [b)] is higher, i.e. , if the air is worse air, then the ventilation effectiveness is less than one, and more outdoor air must be introduced. If the pollution concentration at the breathing zone [a)] is less than the exhaust, i.e. , better air, less air may be introduced.

The formula for determining Ventilation Effectiveness is: i.e. , e_v = c. - c.

Ci - c, where e_v = ventilation effectiveness c_s = pollution concentration in the supply air c_e = pollution concentration in the exhaust air c, = pollution concentration in the breathing zone.

Claims

CLAIMS:

1. A system for improving the condition and quality of indoor air in an inside room space said system comprising: (A) an inflow system comprising: (i) an outdoor air supply unit including an air supply inlet port provided in an air supply discharge duct and a fan connected between said air supply inlet port and said air supply discharge duct for discharging outdoor air through said supply outlet duct; (ii) an air supply unit including an air intake connected to said air supply discharge duct, an air outlet duct, an air outflow duct, and means to control the volume of air discharged through said air outflow duct; and (iii) a tube enclosure suspended from a ceiling of a room, said tube enclosure including a main air inlet port connected to said air outflow duct, a discharge outlet port, and a depending ceiling fan, said tube enclosure thereby feeding outdoor air to the vortex of said ceiling fan to discharge said outdoor air downwardly into said inside room space; and (B) an outflow system comprising: (a) an exhaust grill connected to the ceiling or to a wall of said inside room adjacent the ceiling; (b) an exhaust riser duct connected to said exhaust grill; and (c) an exterior exhaust fan connected to said outlet from said exhaust riser duct; said exterior exhaust fan (c) of said outflow system (B) being operated in conjunction with said fan of said outdoor air supply unit (i) of said air inflow system (A) to exhaust, via said outflow system (B), substantially all the volume of air inflowing through said air inflow system (A) into said inside room through said air outflow by system (B); thereby improving the quality of air in said inside room by: impelling a selected volume of said outdoor air downwardly into said inside room air, circulating said outdoor air within said inside room and expelling said selected volume of used room air from said room, and by allowing the occupant of said inside room to adjust comfort conditions by varying air circulation and the selected volume of outdoor air.

2. The air quality control system of claim 1 wherein said air supply unit comprises a variable air volume box having said air intake which is connected to said air supply discharge duct, said air outlet duct, said air inflow duct and said means to control the volume of air discharged through said outflow duct.

3. The air quality control system of claim 1 wherein said air supply unit comprises said air supply duct which is connected directly to said air intake to the interior of said tubular enclosure, the flow of air to said tubular enclosure being controllably variable, and said air supply unit including heater means within said air supply duct and including controls for controlling the operation of said heater means to control the air temperature.

4. The air quality control system of claim 1 wherein said air supply unit comprises said air supply duct which is connected directly to said air intake to the interior of said tubular enclosure, the flow of air to said tubular enclosure being controllably variable, and said tubular enclosure of said air supply unit having heater means disposed transversely thereacross, and including controls for controlling the operation at said heater means to control the air temperature.

5. The air quality control system of any one of the preceding claims wherein said outflow system (B) is situated exteriorly of said room, e.g. , wherein said outflow system is situated on a roof of a building in which said room is located.

6. The air quality control system of any one of the preceding claims, wherein said air supply unit includes dampers therein; and including control means for controlling said dampers to adjust the volume of introduced outside air.

7. The air quality control system of any one of the preceding claims including means e.g. , a heater, especially an electric heater, to control the temperature of air which is admitted to said air supply unit; and means to control the operation of said heater, e.g. , a temperature limit control switch, especially an internal air temperature limit control switch within said tubular enclosure saturated downstream of said electric heater to control the operation of said electric heater.

8. The air quality control system of any one of the preceding claims wherein overall flow of air is controlled by dampers, which are, e.g. , operated by a motor, especially by an electric motor; and wherein said damper is operable at a minimum air volume less than 20 CFM per person; or wherein said damper is operable between a minimum air volume of 20 CFM and a maximum air volume of 60 CFM per person.

9. The air quality control system of any one of the preceding claims wherein said ceiling fan is driven by a variable speed motor, and including controls to control me speed of said fan; especially wherein said ceiling fan blades project into said room adjacent said ceiling; and more especially including a deflection plate associated with said blades of said ceiling fan.

10. The air quality control system of any one of the preceding claims wherein said outdoor air supply unit includes at least one of a filter, a heating coil, a cooling coil, a fan, and a refrigeration compressor; and optionally, wherein all connecting duct work is insulated.