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Signhild Gehlin, Operating Agent of Annex 52: there is a beauty in efficient energy use

Geoenergy expert Dr Signhild Gehlin describes it as elegant when thermal energy is recycled from the surrounding environment of a building. “The energy that is utilized locally is resource-efficient and is a give-and-take from what is already there by nature”, she states. As the Operating Agent for Annex 52, Signhild has the opportunity to dive into the depth of geoenergy by finding a systematic way to measure and analyse the efficiency of ground source heat pump systems.


The meeting with geoenergy

Dr Signhild Gehlin is a technical expert at the Swedish Geoenergy Centre. In her role as technical expert she cooperates with many geoenergy related institutions around the world, among them Oklahoma State University (OSU) where she is an Associate member of the graduate collage.

Her path started at the University of Luleå in the north of Sweden where she took her master degree in Civil Engineering. One of the classes she attended at this time was about natural energy resources, a door-opener to what would become her greatest passion: Geoenergy.

After finishing her civil engineering education, Signhild continued as a research student and completed her PhD on “Thermal response test” at the University of Luleå in 2002. After the dissertation she worked several years for the Swedish HVAC association Swedvac. In 2013 she was asked by the Swedish drillers organization Geotec to build up a Swedish Geoenergy Centre. This was an offer that matched her ambitions and she accepted.

This is geoenergy
Geoenergy is a term that includes several techniques that use the ground and groundwater as a thermal energy resource for heating, cooling or thermal energy storage. Boreholes in hard rock, pipe loops in soil, groundwater wells and surface water are examples of ground source applications.

Heating and cooling of our homes and other buildings will always be needed, and that energy needs to be made available and used in an efficient and sustainable way. “The good thing with geoenergy is that it is resource-efficient and available locally. The energy resource is there, whether we choose to use it or not”, says Signhild. With ground source applications we can extract the heat when it is cold and extract cold when it is hot. By using and re-using the thermal energy in our close vicinity, we minimize the carbon footprint. “I find this very beautiful”, says Signhild.

Annex 52
Signhild is the Operating Agent for the running HPT TCP (Technology Collaboration Programme on Heat Pumping Technologies) Annex 52 – Long term performance measurement of GSHP Systems serving commercial, institutional and multi-family buildings. The annex emphasizes the importance to generate high-quality long-term measurements of GSHP (Ground Source Heat Pumps) systems.

Today there is no uniform way to instrument, measure, analyse and present the long-term performance of larger GSHP systems. By analysing and optimizing GSHP cooling and heating systems, Annex 52 aims to find a systematic way to instrument, measure, analyse and specify the performance of GSHP facilities. Signhild also believes this will lead to new system solutions that perform even better.

Today, some 40 GSHP larger systems are measured over a four-year period within Annex 52. So far, the involved facilities are analysing their monitoring programs and a survey of previously published long-term performance GSHP monitoring projects has been conducted.

“The outcome of this annex will be guideline documents on how to instrument, measure, analyse and present the performance data”, says Signhild.

Read more about Annex 52 here.