What are Cooling Towers?
Cooling towers are heat rejection devices for use in industry to cool process water for recirculation to the required temperature. They range from small, packaged units to field erected, glass fibre timber structures as well as the concrete hyperboloid structures more commonly associated with power stations.
How do Cooling Towers work?
Cooling towers work by natural evaporative cooling.
E.g. when we are in a shower, immediately when we get out, we feel cold. This is because when we are in the shower our skin is wet and not exposed to air, the minute we step out the shower the shower the water on our skin begins to evaporate and pulls heat out of our bodies.
Cooling towers work in the same basis of pulling heat out of the body of the water.
Cooling towers are part of a structured water system designed to cool apparatus turbines, data centre servers, electronic assemblies, autoclaves, petrochemical, steelworks injection moulding or any activity that generates a significant amount of heat.
They are commonly used to cool water which has been circulated around heat generating apparatus. Once the water has served its cooling requirement it continues its cycle to the circa/spray pump where it is pumped to the top of the tower where it is distributed from a header pipe unit into a manifold of secondary pipework. It is then distributed evenly across the medium or pack as a counter flow or cross flow arrangement through the packing media. Typically in a counter flow cooling tower a fan will drive ambient air upwardly through the pack to meet the descending water and this is where the heat exchange takes place.
Counter-flow and Cross-flow Cooling Towers
These are the two main types of internal arrangements of cooling towers. With cross-flow cooling towers the fan is situated at the top and the water is filtered down and the air is drawn across the pack into the plenum (exhaust area) and exhausted via the fan.
With counter-flow cooling towers the fan can be either on the top (induced draft) or side (force draft) and the air stream is driven upwardly to meet the water descending. Counter-flow is typically one of the most common variant.
Both arrangements would be designed depending on the application required.
Cooling Tower Compliance
In the UK, cooling towers on installation, by law, must be registered with the HSE or local authority. Ongoing compliance is also a legal requirement. To be compliant the cooling tower must adhere to the HSG 274/ Part 1 which is the Health & Safety guidance on cooling on evaporative condensers and ACOP L8 Guidance (Approved Code of Practice).
Cooling Tower Performance
The efficiency of a cooling tower is based on the running costs and water consumption. Cooling towers are the most cost-effective means of cooling and are typically cheaper to run than any other type of cooling. It is strongly recommended that your cooling tower is inspected at least six-monthly and adheres to all guidance.
Cooling Tower Health & Safety
In order for your cooling tower to comply with legionella risk control compliances, the drift eliminators are to be inspected and replaced on a regular basis. Drift eliminators are vital in the prevention of water borne aerosols being in contact with the external environments. These panels are designed to minimise plume to the specification required.
Cooling Tower Inspections
Dakro offer free cooling tower inspections. We can report back our findings including, health & safety performance reports highlighting important factors such as potential for legionella proliferation and bio-film, algae, corrosion, scaling or any operating deterioration.
Cooling Tower Enquiries
If you would like to request a free cooling tower inspection, or have any queries about your cooling towers performance, or health & safety, contact Dakro Environmental today on 0121 559 6431 or enquiries@dakro.co.uk.
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