13 Cooling Tower Selection Mistakes: A Guide for Engineers and Buyers

This guide covers the thirteen mistakes we see most often in tender packages, technical specifications and running sites. In our experience, up to 70 % of companies repeat the same set of mistakes when choosing a cooling tower. Each one costs anywhere from several million rubles in repairs to tens of millions in lost output. Every chapter follows "problem → consequences → solution" and ends with red flags to look for in real commercial offers. It is written for chief engineers, design and lead engineers, and procurement. The PDF is in Russian; the key points are below in English.

What is inside the guide?

• Part I. Eight technical mistakes: sizing for an average summer, the wrong casing material, field assembly, open instead of closed-circuit and vice versa, winter, controls, safety, piping.

• Part II. Two operating mistakes: no chemical water treatment, poor siting.

• Part III. Three economic mistakes: a blind bet on imports, buying without the cost of ownership, comparing offers by the bottom line.

• Part IV. An 18-question tender checklist with columns for three suppliers.

• Part V. TCO (total cost of ownership) structure and a simple 10-year model.

• Part VI. Cold Energy's experience and clients.

If time is short, read at least mistakes 1, 6, 11 and 12: they lead to replacing equipment before it is depreciated more often than the others.

Key takeaways

People save on exactly what drives the cost of ownership. "Saving on the cooling tower" in practice means saving on casing materials, controls and water treatment. These three blocks are about 15–20 % of the installed cost and up to 70 % of the 10-year total cost of ownership. A correctly selected cooling tower lasts 15–20 years.

Select for two points, not an average summer. The summer wet bulb for the region per SP 131.13330.2020 (Russian building climatology code), plus the coldest outdoor temperature with wind load. Red flags in an offer: no design wet bulb, no winter mode, a temperature chart that starts at +10 °C.

A cheap casing gets replaced by year 7–8. Fibreglass and cheap plastic crack after 3–5 years from UV, frost and chlorides. The fix is hot-dip galvanizing of 80–120 µm with a two-sided powder coat, or AISI 304/316 stainless steel for aggressive media, with a service life of 20+ years.

Field assembly never reaches factory quality. A knock-down "site-built" tower means 2–4 months of installation and endless finishing work. A factory module is set in 1–2 working days; NCT lead time is 4–8 weeks, and 2 weeks for standard sizes from stock.

Controls pay back in 2–3 years. Without variable frequency drives the fans run all-or-nothing, wasting up to 50 % of fan energy. Wrong piping eats 15–25 % of system efficiency, and recirculation on a poor site raises the entering wet bulb by 2–4 °C, equal to losing 10–15 % of capacity.

Without water treatment the tower loses heat transfer in the first season. Scale on the fill cuts it by 10–20 %, biofilm adds Legionella risk, and corrosion eats both galvanizing and stainless steel. In Russia there is practically no mains water fit for direct cooling tower make-up without treatment.

The purchase price is a small part of the cost. In our practice the purchase price is 20–25 % of the 15-year TCO, and 55–65 % is electricity and water. In the guide's model, an open cooling tower of 500 kW (100 m³/h) costs a notional RUB 4.5 million, and over 10 years the total reaches RUB 38.7 million: electricity RUB 25.0 million (55 kW × 6,500 h × RUB 7 per kWh), water and chemicals RUB 7.8 million, service RUB 1.4 million. The purchase share is about 12 %. Proper controls save 25–35 % of electricity, or RUB 6–9 million per unit over 10 years.

A 20–30 % gap in the bottom line is often illusory. The cheap offer turns out to have thin galvanizing instead of stainless steel, axial fans without a drive instead of centrifugal ones, and the service platform sold separately. Price comparison makes sense only after normalizing scope across the 18 points.

Who is it for?

• Chief engineers and technical directors: reliability criteria over a 20-year horizon.

• Design and lead engineers: what to check at design and detailed design stages.

• Procurement: how to compare tender offers on substance, not on the bottom line.

FAQ

How do you tell that a supplier is holding something back?

If the supplier leaves 5 or more checklist items unanswered or writes "to be confirmed later", it usually means the item is not in the standard scope and you will pay extra later. Ask for written answers with a reference to the specification.

When do you need a closed-circuit tower, and when is an open one enough?

Closed-circuit is for chiller loops and processes that need a clean heat transfer fluid. Open is for cooling compressors, transformers and gas turbines, where make-up and blowdown are acceptable. Paying for a closed-circuit tower where it is not needed means losing 30–40 % of capital cost.

How long does it take to avoid these mistakes?

All 13 mistakes are prevented in 1–2 weeks of a properly structured selection: sizing for two points, comparing offers on 18 points and calculating the cost of ownership before the tender.

Related articles

• How to choose an industrial cooling tower: open, closed or hybrid

• How much water does a cooling tower use, and how to cut make-up

• How to choose an industrial chiller: 13 costly mistakes

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