Reducing the life cycle impact of an office building by improving systems control. A case study

Abstract

Today construction represents 39 % of global greenhouse gas emissions, of which 28 % are caused by the operational emissions and 11 % are related to materials and construction. Moreover, the embodied carbon in energy efficient buildings could give up to 80 % of life cycle GHG emissions. But practice shows that buildings, which are designed and built as energy-efficient, in reality not always show superb results. A common problem in existing office buildings is the level of systems’ automation, which is often too low and/or management strategies are inefficient. The aim of this study is to perform the long-term monitoring of the indoor climate conditions in the existing office building, analyse the results and evaluate the operational energy-saving potential by increasing the efficiency of systems’ management. Monitoring has shown that during heating season the indoor air temperature is higher than the design temperature and no reduction for unoccupied periods is applied. Also, the amount of the air supplied was without regard to the occupancy of the premises, thus causing overventilation. Thus, potential for energy savings by applying alternative systems’ control strategies was analysed and assessed based on BACS (Building Automation and Control System) methodology which complies with the standard EN 15232-1:2017. Here changing the control system strategies of the existing automation system from class C to B leads to operational heating energy savings of 20 % resulting 235 tons of CO2 (approx. 0.1 t CO2/m2 ) reduction during the 50 years life cycle of the building.