Axel Berge, Carl-Eric Hagentoft, Bijan Adl-Zarrabi, Field measurements on a district heating pipe with vacuum insulation panels, Renewable Energy, Volume 87, Part 3, March 2016, Pages 1130-1138, ISSN 0960-1481, https://doi.org/10.1016/j.renene.2015.08.056.
fashion meets time. We are going bach to wood stoves, natural ventilation and pump-free naturally moved waterheating systems, so heatpipes with their passive work are likely to be fashionnable also. Regarding R&D, no idea really. Still, as I work on thermal storage applications, heatpipes are very intersting devices indeed.