Impact of improved measurements on performance of a smart thermal energy system

In this paper, we demonstrate a successful practical application of an effective measurement algorithm that provides a solution to improve the performance of a smart electric thermal energy system. It is shown that the issues related to the volatility and speed of the boiler power controller observed in current installations is addressed satisfactorily, by accounting for boiler water conductivity with temperature changes. For a typical hot-water boiler, the change in conductivity is almost 20%, which translates to a 15% increase in power consumption in the operational temperature range of the boiler. To ensure a satisfactory control philosophy, a fault-tolerant and redundant measurement is of great importance as well. The new algorithm dynamically modifies the slope of certain xy-curves determined at commissioning based on normalized temperature and accounts for changes in conductivity with changes of temperature. Test results indicated that the mean power error, the difference between actual power and power set point, showed a clear improvement in maintaining load-frequency control, reducing the mean power error to 0 ± 0.5%. The enhanced control algorithm is particularly relevant in applications with increased volatility due to electrical power production by wind turbine.