Buildings have become a major concern because of their high energy use and carbon emissions. Thus, a material-efficient prefabricated concrete element (PCE) system was developed to incorporate... Show moreBuildings have become a major concern because of their high energy use and carbon emissions. Thus, a material-efficient prefabricated concrete element (PCE) system was developed to incorporate construction and demolition waste as feedstock for residential building energy renovation by over-cladding the walls of old buildings. By conducting life cycle assessment and life cycle costing using the payback approach, this study aims to explore the life cycle performance of energy conservation, carbon mitigation, and cost reduction of the PCE system in three European member states: Spain, the Netherlands, and Sweden. The results show that the energy payback periods for Spain, the Netherlands, and Sweden were 20.45 years, 17.60 years, 19.95 years, respectively, and the carbon payback periods were 23.33 years, 16.78 years, and 8.58 years, respectively. However, the financial payback periods were less likely to be achieved within the building lifetime, revealing that only the Swedish case achieved a payback period within 100 years (83.59 years). Thus, circularity solutions were considered to shorten the PCE payback periods. Using secondary materials in PCE fabrication only slightly reduced the payback period. However, reusing the PCE considerably reduced the energy and carbon payback periods to less than 6 years and 11 years, respectively in all three cases. Regarding cost, reusing the PCE shortened the Swedish payback period to 29.30 years, while the Dutch and Spanish cases achieved investment payback at 42.97 years and 85.68 years, respectively. The results can be extrapolated to support the design of sustainable building elements for energy renovation in Europe. Show less
Zhang, C.; Hu, M.; Laclau, B.; Garnesson, T.; Yang, X.; Li, C.; Tukker, A. 2020
Around 35% of the buildings in Europe are over 50 years old and almost 75% of the building stock is energy-inefficient. A European project VEEP is developing an innovative prefabricated concrete... Show moreAround 35% of the buildings in Europe are over 50 years old and almost 75% of the building stock is energy-inefficient. A European project VEEP is developing an innovative prefabricated concrete element (PCE) system to improve the thermal performance of new buildings (PCE1) and old buildings (PCE2). This study focused on retrofitting of old buildings via over-cladding of the building envelope with PCE2. This study aims to from a building owner/consumer’s perspective to explore the life cycle economic performance of the PCE2 system at an early stage and associated cost optimization strategies under the European context. This study tries to answer four questions: 1) whether the use of the PCE2 leads to an economic advantage over a specific life cycle of an existing building. 2) what is the biggest cost stressor in the life cycle of a PCE2? 3) the potential route for further cost optimization. and 4) how would the discount rate affect the life cycle costs, especially when Europe has entered a negative rate age? A typical apartment building in the Netherlands is selected as the case study for dynamic thermal simulation, in which the heating and cooling energy demands before and after refurbishment with PCE2 will be evaluated. By employing environmental life cycle costing (LCC), the life cycle costs over 40 years and associated strategy for cost optimization will be investigated. This research not only unveils meaningful financial implications on resource-efficient building energy retrofitting in Europe but also provides insight on methodological dilemmas within the application of LCC. Show less
