Analysis, evaluation, and optimisation of the operation of the mechanical ventilation of apartment buildings in terms of energy consumption, economic efficiency, and environmental safety

Abstract In this thesis, we present alternative ventilation solutions with heat recovery to reduce energy consumption in apartment buildings: decentralised ventilation compared to local ventilation. The aim is to analyse, evaluate, and optimise the operation of mechanical ventilation. The parametric study of energy, economic, and environmental calculations focuses first on a single apartment and then on the entire apartment building. Local heat recovery units have been designed for the ventilation of the apartment building. The share of heat loss through ventilation is 45% of the total design heat output for heating the building. Considering the UN Sustainable Development Goals, particularly Goal 7 (affordable and clean energy), we evaluated an alternative using decentralised heat recovery units with enthalpy heat exchangers. This approach achieved significant thermal energy savings, covered heat losses due to ventilation, and provided improved air and environmental quality in the apartment building. In this case, the share of ventilation heat losses in the apartment building is only 13% of the total design heat output of the building. The total heat output of the heat source was reduced by almost 78.78 kW, and the energy savings of the decentralised units amounted to 151.30 MWh, a reduction of 44% compared to the local ventilation units. Although the initial investment cost is about 45% higher than for the local units, the return on investment is achieved within 6 years of operation. The proposed solution represents a 58% saving in primary energy for ventilation and an 81% reduction in CO 2 emissions.