Enegry-saving air cooler

Evaporative Cooling Free Air System

How are the savings achieved?
An Aolan cooler free air system provides a constant flow of attemperated air between 25°C and 30°C.  No refrigeration is used – the air is cooled by evaporative cooling when ambient temperatures are high and is heated by recirculation of air from the server exhaust when the ambient temperature is low.  No refrigeration is used as all of the cooling is achieved using evaporative cooling.  This results in energy saving in excess of 90% compared with traditional Computer Room Air Conditioners (CRAC’s)

1 – Fresh air is brought into the system though primary filtration and wetted filter pads
2 – Evaporative cooling operates during warm periods
3 – Low energy axial fan air distribution
4 – Patented control system controls air supply temperature
5 – Air flow is matched to density of cooling required
6 – Hot and cold aisle arrangement of racks is preferred
7 – Room is kept at a positive pressure
8 –Ceiling void can be used for exhaust path.
9 - No exhaust fans are used to reduce complexity and energy use
10 - Hot air is exhausted to atmosphere

System Design

The air flow required of the system is dependent upon the total IT load and the server design.  Using a typical ΔT of 10C a single Aolan cooler  CREC can support a load of 35kW.  The systems can be either fixed or variable flow.

The low energy air distribution system uses axial fans which can accommodate most applications.  Where raised floors are used, the overall design, in particular the floor grill numbers and position, should reflect the pressure drops and rack cooling load density.

Most systems are controlled centrally.  This allows fully automatic control and identification of any fault conditions.

Server and IT operating conditions

The following must be taken into account when providing a cooling solution:

Temperature:  In Europe an Aolan Cooler  can provide 100% compliance against the latest ASHRAE[1] standards and meet all manufacturer environmental specifications. Some early main frame systems require close control and evaporative cooling is not suitable.

Relative Humidity:  In Europe an Aolan Cooler can provide 99% compliance against ASRAE allowable conditions.  Older equipment such as paper tape and magnetic tape systems are less tolerant and evaporative cooling is not suitable.

Dust:  The filter pads provide an adequate level of filtration for modern IT equipment with sealed bearings and closed drives.

Redundancy – The required redundancy is met using the modular system.

BENEFITS

The key benefits of using Aolan Coolers compared with conventional refrigeration based air conditioning are:

Cost

·                                                                                                                                                                                                                 Over 90% reduction in electricity usage

·                                                                                                                                                                                                                 Lower capital costs

·                                                                                                                                                                                                                 Lower maintenance costs

·                                                                                                                                                                                                                 Aolan Coolers qualify for Interest free loans from the Carbon Trust and Salix schemes.

Engineering

·                                                                                                                                                                                                                 Low energy ventilation system

·                                                                                                                                                                                                                 Low cost spare parts holding

·                                                                                                                                                                                                                 No F gas compliance costs

·                                                                                                                                                                                                                 Simple technology

·                                                                                                                                                                                                                 Ability to cope with very hot days

·                                                                                                                                                                                                                 Allows release of available power for other activities

Operational

·                                                                                                                                                                                                                 External access for maintenance.

·                                                                                                                                                                                                                 No internal space used

·                                                                                                                                                                                                                 Modular system achieves required redundancy

·                                                                                                                                                                                                                 Simple expansion through modular design

Environmental Benefits

·                                                                                                                                                                                                                 No refrigerants

·                                                                                                                                                                                                                 Less than 10% of the carbon footprint of conventional air conditioning

·                                                                                                                                                                                                                 Can fit into Carbon Reduction Commitment energy reduction scheme

[1] - 2008 ASHRAE Environmental Guidelines for Datacom Equipment

Where can Aolan Cooler be used?

Aolan Coolers require ducting from an outside wall or roof.  Modern data centres and server rooms can easily accommodate both data rack cooling and UPS room cooling.

1 – Aolan evaporative coolers are externally fixed
2 – Modular systems provide simple compliance with tiered redundancy levels
3 – Existing CRAC systems can be retained
4 – Air is supplied to the underside of the raised floor.
5 – Standby generators only have to support 10% of the electricity consumption of the CRAC systems.
6 – UPS rooms are cooled with simple ventilation systems utilising evaporative cooling
7 - Aolan Coolers are linked to all fire systems for controlled shut-downs.
8 – Typical roof mounted EcoCooler.

Useful links about new approaches to cooling of data centres and server rooms.

Intel’s proof of concept of fresh air cooling in New Mexico.
Note the following:

·                                                                                                                                                                                                                 Very little control compared with EcoCooling

·                                                                                                                                                                                                                 No significant filtration compared with EcoCooling

·                                                                                                                                                                                                                 No increased failure!

·                                                                                                                                                                                                                 Recognition of changing standards of environmental standards for modern equipment.

·                                                                                                                                                                                                                 Hot and cold aisles being important