Mittel research finds value in testing, use of welded muff joints

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Swedish energy technology company Mittel has concluded very promising tests to find at solution to a huge problem in the district energy industry: the difficulties with installing functioning, and frequent absence of, effective moisture alarm systems in cooling pipes. The tests show that it is possible to install fully functioning and durable moisture alarms in cooling pipes by dehumidifying the air in the joint muffs before insulation, and by always using welded muff joints for district cooling pipes.

Mittel Fjärrvärme AB, a Swedish energy technology company specializing in district energy, has carried out a study on the construction of moisture-free district cooling pipes together with the Swedish District Heating Association, Umeå Energi AB and Pipeguard. The results show that it is possible to use the same cost effective and proven alarm technology which is standard on insulated pipes for district heating, also for district cooling by dehumidifying the air in the muffs before insulating them. The method can give energy companies opportunities to prevent future costly leaks from pipes.

District cooling systems are often built without effective moisture alarm. The reason is that moisture often cumulates in the insulation and impairs the copper alarm wires. Without a functional moisture alarm system, the ability to detect and locate leaks is seriously impaired. District cooling pipes often suffer from costly leaks and repairs.
The new method that Mittel and its partners have now tested in Umeå in northern Sweden is based on the process of dehumidifying the air in the muffs before insulating them. The district cooling pipe case joints are dried and dehumidified before foaming, and subsequently jointed with welding sleeves using the patented Mittel TSC method. Mittel TSC is an advanced method for case jointing of pre-insulated pipes with welding sleeves that makes the joints as strong and durable as the pipes.

District cooling is a cost and energy effective, and environmentally friendly method to cool buildings with very promising growth potential in especially warmer countries. The systems are technically constructed in the same way that district heating systems are constructed – but the moisture problem is much greater. The moisture problem has led to energy companies not even bothering installing leak detection systems due to the systems inevitably and quite quickly being destroyed by the moisture.

The study by Mittel & Co shows that it is possible to install functioning alarm systems by making the joints practically completely moist free, by using standard equipment for dehumidification. As a result, energy companies could also use the same monitoring centrals for district cooling that they use for district heating.

“This is great news for heat plants and energy companies all over the world. Monitoring with alarm wires has been a huge success in district heating; now it can be used for district cooling as well”, said Lars Gunnarsson, CTO, Mittel.

“We strongly recommend to always use welded muff joints for district cooling pipes. Leaking joints can have major consequences when you deal with cold pipes.”