Bringing EnergyNest’s thermal energy storage (TES) to life!

29. November 2016 Applications, Projects, Technology

Once construction of an EnergyNest TES is finished, it is time to make it work. Commissioning an EnergyNest TES is straightforward, at the same time it is important that it is carried out correctly to ensure that the TES performs optimally throughout the duration of the contracted lifetime.

Commissioning involves testing and functional verification of all components and instruments, and to bring the TES to operational status. Commissioning is divided in two stages; “cold commissioning” and “hot commissioning”. As the name implies, cold commissioning is conducted at ambient temperature while hot commissioning brings the TES to operational temperature.


In cold commissioning the objective is to test all elements that have an active function in the control and monitoring of the TES. This includes temperature sensors, flowmeters, valves, and more. Once all elements are tested individually, it is time to check, verify and adjust general performance. One example is to conduct sequenced opening and closing of valves and test various operation modes (charge, discharge, etc.). Another example is to adjust functionality of the system and control temperature and pressure inside the TES. Everything must be tuned for the correct operation of the TES.

Hot commissioning represents the most critical phase in the commissioning process. The critical issue during hot commissioning is to expel all chemically unbound water in the HEATCRETE® in a controlled manner. This is done by slow heating and maintaining certain temperature levels for an extended period of time. As the temperature rises above 100°C, water starts to evaporate and a vapor pressure builds up inside the HEATCRETE®. By slow and controlled heating the water will diffuse and escape to atmosphere before this pressure reaches too high levels. Once all water is expelled the TES has gone through a “thermal conditioning” phase, at the same time the mechanical strength of the HEATCRETE® has doubled! Now the TES is ready to be brought up to the maximum temperature.


The last part of the commissioning phase involves training plant operators to run the TES correctly and effectively, making sure that we transfer correct information and knowledge concerning O&M to their team.