A full-scale thermo-hydraulic simulator for the characterization of building heat cost allocation methods

An innovative heat accounting method for apartment buildings, named EcoThermo, based on the estimation of water flow rates at each radiator by thermo-hydraulic modelling of the hot water distribution system, has been developed in the framework of the EU Programme FP7-SME-2012. In order to validate this approach and to compare it with conventional Heat Cost Allocators (HCA), a full-scale thermo-hydraulic simulator has been recently built at INRIM. This INRIM test facility represents a real-scale hot water heating system consisting of a gas-fired boiler and 40 radiators of different characteristics, mimicking a four-story residential building. Each radiator is equipped with an electromagnetic flow meter and a pair of short-stem Pt100 PRTs immersed in the water flow for inlet and outlet water temperature measurement, such that the radiator thermal output can be determined by direct metering, providing an accurate reference value against which indirect allocation methods can be compared and assessed. The paper describes in detail the INRIM thermo-hydraulic simulator, highlighting its design features and metrological capabilities and discussing key results of the investigations carried out so far on different heat accounting approaches. The accuracy of the EcoThermo model has also been assessed against direct heat metering and HCA approach.