Hydraulic Parameter Estimation for District Heating Based on Laboratory Experiments

TL;DR

This study develops and tests a calibration method for hydraulic models in district heating systems, accounting for real-world complexities like valve behavior and hysteresis, using laboratory data.

Contribution

It extends existing theoretical models to handle practical issues such as unknown valve characteristics and hysteresis in hydraulic parameter estimation.

Findings

Model predicts flow rates within 5-10% deviation in controlled scenarios

Performance is consistent within the operational range of training data

Model accuracy decreases when evaluated outside the training data range

Abstract

In this paper we consider calibration of hydraulic models for district heating systems based on operational data. We extend previous theoretical work on the topic to handle real-world complications, namely unknown valve characteristics and hysteresis. We generate two datasets in the Smart Water Infrastructure laboratory in Aalborg, Denmark, on which we evaluate the proposed procedure. In the first data set the system is controlled in such a way to excite all operational modes in terms of combinations of valve set-points. Here the best performing model predicted volume flow rates within roughly 5 and 10 \% deviation from the mean volume flow rate for the consumer with the highest and lowest mean volume flow rates respectively. This performance was met in the majority of the operational region. In the second data set, the system was controlled in order to mimic real load curves. The model trained on this data set performed similarly well when evaluated on data in the operational range represented in the training data. However, the model performance deteriorated when evaluated on data which was not represented in the training data.