Sterling Thermal Technology Ltd.

Cool under pressure

Producing heat transfer equipment primarily for the oil and gas industry, Sterling’s name may be relatively new to the marketplace though it boasts origins dating back over 100 years as a supplier of combustion and heat exchange technology to the process engineering industries.

Managing director Peter Michaluk elaborates on the business’ history and credentials: “Sterling Thermal Technology (STT) is an amalgamation of companies that individually date back as far as 1904. Today we’re best characterised by several companies whose names are now associated with particular product types.

“Thermo Engineers was established in 1924 and supplies various heat exchangers designed with finned tube as the heat transfer surface; Heat Exchange Industries (HEI) designs and manufactures heat exchangers using fin blocks rather than tubes; and Urquhart Engineers is a supplier of oil fired burner systems. Argo Flare Services, which supplies design, inspection and refurbishment services as well as new flares for oil and gas production and processing has recently become a standalone business.”

STT has been part of Sterling Industries for over 25 years, with the latter being wholly owned by Caledonia Investments Plc. Since 2006, when Peter took over as MD, the business has undergone significant refocusing with the elimination of non-profit making product lines and with new investments in R&D, manufacturing machinery and software. During this time there has been impressive growth in sales and profit with last year’s turnover reaching almost £15 million.

Today, STT supplies a wide range of heat exchange products with a particular focus on the electrical machine cooling market and products largely based upon its proprietary high efficiency extended fin surface. The application of the heat exchangers is principally for the cooling of generators and large motors by transferring the heat within the circulating air with water (CACW). In the case of very large generators hydrogen may be used instead of air but still with transfer of heat to water. Peter reveals more: “When cooling water is unavailable these electrical machines will be cooled by air to air heat transfer (CACA coolers). We also supply a wide range of other heat exchangers based upon fin tube or block fin surfaces, including air blast coolers (oil/water/glycol), air heaters, HP gas coolers, transformer oil coolers, and specialist process coolers.”

Benefiting from STT’s comprehensive services and knowledge bank, the company’s key customers are large mainly European-based generator suppliers such as Brush, Siemens, Converteam, ABB and Alstom, who know they’ll be able to arrange for a tailor-made solution to be delivered, which Peter feels is one of the organisation’s many qualities. “Whilst we’ve developed and supplied significant numbers of standard range coolers, our strength is in supplying bespoke packaged solutions utilising the most efficient heat transfer technology,” he asserts. “We have strong technical capabilities and great experience that has allowed us to also offer services for the redesign, refurbishment and upgrade of old heat exchangers – and this can include reverse engineering where the original designs or suppliers are no longer available.”

The introduction of the Avantair heat-pipe cooler has been a major success, with over 80 units now in successful operation with major oil companies such as BP, Shell, Total and Chevron. There is increasing interest in the application of this technology, and a major owner of FPSOs recently purchased nine identical Avantair units. “Some of our major OEM customers have now recognised the benefits of this technology and are promoting the technology to their end-user customers,” Peter shares.

“The Avantair was developed to solve a problem in oil and gas where traditional air-to-air coolers (CACA) become very large when operated in high ambient temperatures. Space and weight is at a premium on offshore platforms and FPSOs. Whilst there is always the option to use an air-to-water cooler, this requires high water volumes and possibly a secondary exchanger if the water is recycled. Any cooling water offshore is likely to be corrosive seawater, meaning that the water circuit needs to be constructed of expensive duplex stainless steels, copper-nickel alloys or even titanium.

“The Avantair utilises heat-pipes (or thermo- syphons), which are sealed tubes filled with a refrigerant that vaporises at the temperature of the generator but condenses at the ambient air temperature. The continuous evaporation and condensation produces a highly efficient thermal transfer to allow the space and weight of the cooler to be reduced by up to 50 per cent compared with conventional air-to-air coolers.”

Such advances place STT in an excellent position in terms of market standing, and for this reason the company is committed to offering its customers the latest technology. “We’ve made improvements to design configurations and manufacturing methods to reduce production time and improve product quality,” Peter states. “The improvement in manufacturing methods has required investment in new machine tools including a new custom designed automated press for producing the complex fin patterns used in our exchangers.”

By focusing on bringing innovations to market, the business has safeguarded its future in light of the global economic problems. Speaking about the current challenges, Peter says: “Our markets were some of the last to slide into recession but there is now a significant downturn with the delay of major capital projects. It’s difficult to predict when the upturn will come but historically our industries have postponed, rather than cancelled, projects. Reports regarding the state of the UK’s power plants and increasing oil prices are two strong drivers for shorter-term recovery of our markets. The reduction in the value of the pound has improved our international competitiveness.”

With thoughts turning to STT’s future, Peter shares his vision for the business: “The move towards using CNG for powering environmentally friendly vehicles will provide an opportunity to further exploit its high pressure gas cooler technology. In recent times the heat exchange business in the UK and Europe has become fragmented with several major companies disappearing. This trend may reverse with the emergence of larger businesses through consolidation, presenting opportunities for major growth and the achievement of our target to be the premier UK heat exchange company.”

Sterling Thermal Technology Ltd.

Products Heat exchange equipment