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Cyclonic Air Conditioning Systems

(CACS)

 

a unique Air Conditioning System:

 

 without mechanical filter & maintenance !

 with efficient micro-organisms & particle centrifugation

& direct evacuation to the drain !

 self cleaning & sanitary design !

 

 

Contents:

1. Introduction
2. Process Description

3. Features

4. CACS Models & respective locations

5. Particle removal efficiency 

6. Micro-organism removal efficiency

7. Humidity Removal Efficiency

8. Major Advantages of the CACS

9. Recommendations in the AFNOR norms

 

 

1. Introduction   [ top ]

 
The Cyclonic Air Conditioner (CAC) is a unique & patented concept for conditioning air loaded with humidity or/and high concentrations of particles above 0.5µm. The fine water droplets, the particles and the micro-organisms are separated by a very high centrifugal force instead of mechanical filters.
 
It can not only regulate the air T° and the humidity  but also centrifuge and directly evacuate to the drain the airborne particles as small as 0.5µm and the micro-organisms, and this without mechanical  filter and consequently without clogging risk.

 

The sanitary design of the CAC, completely realised in Stainless Steel (304 or 316), allows its installation outside or inside the room to be conditioned.

 

2. Process Description   [ top ]
 
The CAC can be divided in 2 sections:
  • the lower section, integrating the air inlet (1) and the cooling coils (2)

  • the upper section, integrating the air outlet (9), the fan (7) and, if necessary, the heating coils (8)

The air is forced by the fan (7) to flow downwards in the cyclone and to follow between anda long the coils (3); the condensates and contaminants are centrifuged (4) and evacuated to the drain (5) via a water film continuously formed on the wall ; the air is afterwards sucked to the top through a central chimney (6) and is heated up, if necessary, with heating coils or electrical resistance (8).

 
The introduction of cooling coils in the CACS has 3 major advantages compared to a standard cyclone:

 

1. since the slope of the cooling coils is low and since the air flow is forced to flow down along the coils, the centrifugal force is a lot higher than in a standard cyclone, where the slope of the air flow is as high as 45°. Consequently the particle removal threshold drops from 5µm down to 0.5µm, which means that micro-organisms and aerosols can also be removed.

 

2. since the presence of the coils reduces the turbulence in the CACS, the pressure drop in a cyclonic heat exchanger is lower than in a standard cyclone

 

3. thanks to the water condensation & centrifugation, a water film is permanently formed on the cyclone wall and continuously evacuates the air contaminants to the drain

 

Standard Cyclone:
 
 

Particle removal  > 5µm 

CACS:
 
 

Particle removal  > 0.5 µm

 

3. Features:   [ top ]
  •  The whole CACS construction is made of stainless steel 304.
  •  Any kind of cooling fluid, like glycol water, freon and liquid nitrogen can be used.
  •  The air humidity can be increased by just spraying water in the air inlet
  •  The CACS can be easily manually cleaned, by dismantling the different superposed elements, or CIPed (Cleaned-in-Place) by just spraying hot water, with our without detergent, in the air inlet. The fan must be working in order to carry the cleaning fluid through the whole system. A CIP cycle is compulsory if sticky dust is present.
  •  If negative temperatures have to be used, the coils can be easily and quickly defrosted:

 - for glycol water, by just isolating & recirculating the cooling fluid

 - for freon, by just briefly circulating the warm freon tapped at the exit of the compressor

  •  Ice formation in a CACS is much lower than in standard systems since condensates are quickly removed.

 

4. CACS Models & respective locations   [ top ]

The sanitary design of the CACS, completely realised in Stainless Steel (304 or 316), allows its installation outside and inside the room to be conditioned.

 

4.1.  Location outside the room:

The CACS can be either installed on the roof or beside the room to be conditionned. The fact that the CACS is compact and does not require maintenance space around its structure, allows its installation in small technical rooms.

 

 
4.2.  Location in the room:

The compact and sanitary design of the CACS, that can be realized in stainless steel 304 and 316, allows its installation in the room to be conditioned.

 

4.2.1. Airec’Cold®  design [ Back ] 

 

The Airec'Cold® model, installed in the room, only needs an air duct for distributing the air:

 

 

Available sizes: 300, 500, 1000, 1600, 2500, 3500, 5000, 7500, 10.000, 12.500 m3/h

 

Up to 3500m3/h, the Airec'Cold® can be supplied on skid, with the cooling group and the regulation.

 

4.2.2. Airec’Art®design [ Back ]

 

The Airec'Art® model works without duct! It is a tower integrating in its upper part an Airec'Cold® . The cyclone aspirates the contaminated air at a height above 3m and diffuses at its lowest part the cleaned air at low air velocity (< 0.3m/s) through a diffusion perforated screen. 

a tower integrating in its upper part an . The cyclone aspirates the contaminated air at a height above 3m and diffuses at its lowest part the cleaned air at low air velocity (< 0.3m/s) through a diffusion perforated screen. 
This Airec’Art®  system is particularly recommended for large rooms with high ceiling since it blows clean air in the volume where people are working, without disturbing them.

 

                        

Available sizes: 1000, 2500, 5000, 7.500, 10.000 m3/h

 

 

 

 

 

Fish Market   

« La Marée »

(Rungis, F)

72 x Airec’Art 5000

 
 

 

5. Particle removal efficiency   [ top ]

 
Thanks to the high centrifugal force and the low turbulence, particle as small as 0.5 µm can be efficiently removed

 

The removal efficiency depends on the humidity content. The higher the humidity, the higher the removal efficiency.

 

The water condensation helps to entrap hydrophilic molecules and very fine particles which can normally not be centrifuged.

 

Regarding Clean rooms, classes ISO 8 can be obtained, without mechanical filter; if the air humidity is high enough, even ISO 7 classes can be achieved !

 

Validation study: Surgical room in the hospital of Lyon 

 

An Airec'Cold 1000 installed above the surgical room recirculates the air at 38 vol/h; test conditions in a manned area:

  •  Room volume:  30m3       
  •  Air flow:     1150m3/h                        
  •  Air renewal:  38 vol/h                         
  •  Fresh air: 10 vol/h
  • [particles > 0.5 µm] t=0 : 25 x 106 part/m3

Results:

  • > 99,9% removal for particles > 5µm
  • > 60% removal for particles > 0.5µm

 

6. Micro-organism removal efficiency    [ top ]

 
Thanks to the high centrifugal force, micro-organisms are efficiently removed and directly evacuated to the drain.

 

The Aireco cyclone, continuously recirculating the air in a manned room, is able to keep the micro-organism concentration in the air below 40 CFU/m3, with abatement efficiencies in the cyclone above 99.9%.

 

Validation study: surgical room at the hospital of Lyon 

 

An Airec'Cold 1000 installed above the surgical room recirculates the air at 38 vol/h; test conditions in a manned area:

  •  Room volume:  30m3                             
  •  Air flow:  1150m3/h                           
  •  Air renewal:  38 vol/h                        
  •  Fresh air: 10 vol/h
Results:
 

Time (min)

PCA (cell/m3)

Sabouraud (cell/m3)

0

694

6

20

28

0

40

22

0

60

33

0

Efficiency max

97 %

100 %

 

7. Humidity Removal Efficiency   [ top ]

 
Thanks to the high centrifugal force in the CACS, the fine water droplets entering or formed via condensation in the cyclone are efficiently centrifuged, which helps to quickly dehumidify a room.

The following pictures show that, after a sterilisation cycle in a conditioning room (dairy industry), the CACS can remove the mist after a couple of minutes and dry all the surfaces (floor, wall, ceiling, process equipment) in the room after 1/2h.

 

 

 

 

 

 

 

 

 

The water coming out of the drain is often nearly sterile since the high centrifugal force may kill certain types of micro-organisms.

 

 

8. Major Advantages of the CACS    [ top ]

  •  Very high micro-organism & particle removal via condensation and centrifugation - direct evacuation to the drain
  •  No dirt accumulation thanks to high shearing & centrifugal force -  air velocity: as high as 10 – 15 m/s
  •  No filter => no fouling & contamination risk
  •  Low pressure drop ( < 300 Pa) and no pressure drop increase
  •  very efficient dehumidification – direct condensate evacuation
  •  deodorization effect via condensation of hydrophilic odorous molecules
  •  sanitary design: 100% stainless steel - no dead legs
  •  easy and short CIP and/or defrosting cycle (option)
  •  no parts to be exchanged, except the fan: no maintenance
  •  construction 100% in stainless steel (304 or 316) => very long  service life
  •  small space requested – none for maintenance
  •  duct network not compulsory: the system can be installed in the room to be conditioned

 

9. Recommendations in the French AFNOR norms NFS 90-351 for clean rooms   [ top ]

AFNOR NFS 90-351

Clean Rooms in Health Institutions

Annexe F

“Mastering of the air cleanliness”

(extract)

« Other kinds of processes using different physical separation processes,

based for instance on the air centrifugation and condensation,

can be used for mastering the air contamination in clean rooms »

 

 

© 2008 Air Quality Concept