Paper Conference

Proceedings of BSA Conference 2015: Second Conference of IBPSA-Italy


Estimation of the water flow rate and energy consumption of a central heating system in an office building using system identification

Daniele Antonucci, Federico Noris, Ulrich Filippi Oberegger, Andrea Gasparella

Abstract: This study focuses on the application of system identification to estimate the flow rate and the heating consumption in a central heating system in an office building in San Michele all’Adige, Italy. The study was done within the European ICT PSP project Smart Build with the aim of reducing the energy consumption of existing public buildings through the application of ICT systems. The installed monitoring system, designed after an early energy auditing, foresaw the use of permanent temperature sensors coupled with a portable flow rate meter, to estimate thermal consumption. The flow rate varied with time depending on several factors therefore making it challenging to monitor it for only a short period. To overcome this obstacle, we monitored the flow rate for four workdays and one weekend to identify a mathematical model which could explain the real system behaviour. A statistical analysis was performed at first to assess the reliability of the monitored data. Subsequently, we focused on the identification of autoregressive models with exogenous inputs with a varying complexity and level of confidence. Different tests were performed on the hourly data to assess the reliability of the models. The best model was subsequently used to estimate the timevarying heating consumption for available monitoring periods with the aim to understand the impact of the ICT system as a function of the floor of the building and in order to show how system identification can reliably estimate the water flow rate in a central heating system and consequently be used to calculate the heating consumption. The calculated monthly average deviated from the bills by 20%, attributable to the heating consumption of the non-monitored ground floor.
Pages: 247 - 254