Thermoeconomic analysis of a thermal system supplied with heat pump and auxiliary boiler for heating

Resumen

The European Directives promote the use of energy from renewable sources and defines a common system to promote energy from renewable sources in all sectors. These efforts are transposed to the Spanish legislation by the National Integrated Energy and Climate Plan 2021-2030, in which Spain has set out to improve its energy efficiency and reduce primary energy consumption. Therefore, reducing energy consumption is in the spotlight of many researchers, especially in the sectors with the greatest potential for consumption savings, which are buildings, along with transport and industry. Because of that, one of the important new features of the Building Technical Code (CTE in Spanish) 2019 has been the widening of the technologies allowed for compliance with section DB-HE4, and Heat Pumps become eligible to reach the minimum renewable share in DHW and heating production. The Department of Territorial Planning, Housing and Transport of the Basque Government has a Laboratory of Quality Control of Buildings (LCCE) to carry out diverse testing on construction materials, components, systems and construction sites to assess compliance and enhance the quality of mechanical properties, acoustics and energy efficiency. The ENEDI Research Group of the University of the Basque Country (UPV/EHU) works in the Thermal Area of the LCCE improving the energy efficiency in new developments, existing buildings and refurbishments, as well as promoting the use of renewable energies; through experimental tests, research activities, training and advising society on the energy performance of buildings. An experimental facility bench allows testing of different configurations of thermal systems, by emulating real thermal and DHW demands. The main objective of this work is to show the results of an experimental test carried on LCCE’s system laboratory that reflects the dynamic behaviour of an Air Source Heat Pump (ASHP) thermal facility to cover the heating demand of a multifamily house. The smart control gives priority to the ASHP according to the dynamic demand and external conditions, so the auxiliary condensing boiler is activated in peak demands. A thermoeconomic analysis is applied, that is, an analysis that considers the two laws of thermodynamics and uses exergy as a basis. Thus, cost-sharing along the system is performed and the cost formation in each operation mode is evaluated in depth. The most inefficient equipment and the equipment that generates the most overcosts for the installation have been identified. This extensive analysis is very useful for further implementation of heat pumps in thermal refurbishments as well as for energy savings in buildings.