Towards non-invasive temperature measurements in HVAC: A characterization and correction approach

The existing building stock within the European Union is responsible for a considerably huge amount of the total energy consumed. This has prompted legislative actions that focus on increasing the efficiency of Heating, Ventilation and Air Conditioning facilities by employing building automation and electronic monitoring systems. The fluid flow temperature in the hydraulic grid of a building is therefore an essential parameter to be measured, where clamp-on temperature sensors are often applied due to their simple and cost-effective installation. As the plumbing industry heads towards non-metal pipe materials with low thermal conductivity, the applicability of non- invasive measurement procedures diminishes. In this context, a characterization approach of non-invasive temperature measurements that is linked to a thermal resistance model is experimentally validated. Based on that, a correction algorithm to reduce the deviation between measured surface and the fluid flow temperature for steady state conditions is derived and tested. The presented approach provides sufficient characterization and correction performance, albeit several limitations have to be taken into consideration.