1:00pm - 1:15pm
Circularity concepts for offsite prefabricated energy renovation of apartment buildings
1nZEB Research Group, Tallinn University of Technology, Estonia; 2Smart City Center of Excellence (Finest Twins), Tallinn University of Technology, Estonia; 3Zuyd University of Applied Sciences, The Netherlands; 4Huygen Installatie Adviseurs, Netherlands
Deep energy renovation includes the realisation of the full potential of energy performance. A circular deep renovation, which contributes to a circular built environment, is based on 100% life cycle renewable energy, and all materials used within the system boundaries are part of infinite technical or biological cycles with the lowest quality loss as possible. In the current study, the circularity potential was assessed for deep energy renovation from different aspects: circularity of materials, building component and building structure. Careful selection of materials as well as connection, position and disassembly possibilities are needed to increase the degree of circularity. This shows a good possibility to increase energy performance by using circularity principles. The window glass circularity analyse showed that, at best, the thermal transmittance of a new circular product can be more than three times lower than the original. The circular use of materials, components, and structures pose new challenges for the building physic design of building envelope structures.
1:15pm - 1:30pm
Benchmarking heat consumption in multi-storey residential buildings
Aalborg University, Denmark
The heat consumption in comparable multi-storey residential buildings can vary significantly from building to building, just as the consumption in a building varies from year to year. The former typically relates to state of repair and realised energy improvements, composition and number of tenants, caretaker skill and enthusiasm and similar factors, while the latter usually relates to weather (temperature, wind, and sun). Therefore, it can be very difficult for a building owner to assess whether a specific building performs satisfactory, what the energy saving potential is of specific energy improvements and the value of optimising operational control parameters.
In 1990, Technological Institute in Denmark analysed 23,000 Danish dwellings divided into 92 typical multi-storey buildings. This study included measurement data for the 1970s and the years after the energy crisis and the first tightening of the building regulation’s thermal requirements. The study showed significant reductions in energy consumption. In an ongoing study of the heating consumption in Danish multi-storey residential buildings, 18,000 dwellings with a total heated area of 1,056,000 m2, is being analysed. This study includes measurement data from the last 10-20 years and thereby cover a period with an increasing focus on environmental and climate impacts of energy consumption. During these two decades, the heat consumption has increased and decreased, but the consumption is more or less the same today as it was in 2000.
This paper presents a comparative study of the two sets of measurement data and thereby energy saving efforts. In addition, the results feed into a web-based benchmarking tool using key indicators like monthly energy consumption, energy signatures and annual carbon emission. The purpose of the benchmarking tool is also to predict the effects of energy saving measures and to estimate pre- and rebound effects.
1:30pm - 1:45pm
A NEW FLEXIBLE, MODULAR AND CIRCULAR WAY OF BUILDING AND LIVING: THE MOBBLE
Ghent University, Building Physics Research Group, Belgium
The EU aspires to achieve a climate-neutral building stock by 2050. However, coming decades population growth and the trend towards more single families will also entail an increasing necessity for new homes. For Belgium it is estimated that approximately 400 000 additional dwellings are required, which raises a critical question: how will we build future-proof environmental-friendly homes?
Students at Ghent University developed ‘The Mobble’: a flexible, modular and circular building system, which is adopted to build 15 houses in 2020. One Mobble comprises 10 prefabricated floor and roof panels, and 2 structural frames with each 3 columns. Through an iterative design process and optimised sizing, all components are interchangeable, can be disassembled and reused following the circular concept. The dimensions (2.4m wide, 6m long, 3.1m high) allow easy transportation and on-site placement. Several Mobbles are placed side-by-side airtight and watertight in one day. The modularity facilitates the owners’ need, making material use more efficient on a large scale in which people's opposite needs can complement each other.
Firstly, for all material choices the environmental impact is considered using Life Cycle Assessment (LCA). Secondly, an optimisation exercise is executed to determine the trade-off between operational and embedded energy, considering advanced demand-driven services combined with personal comfort systems. The energy use is simulated in Modelica/Dymola. Thirdly, this concept is compared with an equivalent house built according to Belgian standard practice (concrete slabs, PU insulation and brick walls). The environmental impact of both is first determined at element level, followed by an evaluation of the whole building. Both results are compared in order to assess to what extent ‘The Mobble’ is environmental friendlier than business-as-usual.
This iterative design process results in a modular building block out of environmental-friendly materials with an optimized insulation thickness and a lower environmental impact than business-as-usual houses.
1:45pm - 2:00pm
A preliminary scenario analysis of the impacts of teleworking on energy consumption and greenhouse gas (GHG) emissions
Department of Civil and Environmental Engineering, Carleton University, Ottawa, Canada
Although many people have been forced to work remotely due to the COVID-19 pandemic, work patterns in office buildings were already transitioning due to technological advances, enabling many to work remotely or “telework”. While these working arrangements may have the potential to greatly reduce an organization's need for real estate and personal transportation for commuting, telework has not proven to save energy and reduce greenhouse emissions on a bigger scale. The aim of this paper is to investigate the broader impact of teleworking in four scenarios including the COVID-19 pandemic, worst-, moderate-, and best-case scenarios on building-level energy use, energy consumption in transportation, and information and communication technology (ICT) usage. The analysis of the COVID-19 pandemic relies on the available data for the pandemic period that shows 21.6% of Canadians switched to teleworking during the pandemic. The worst-case scenario is when telework has an adverse effect on energy use while the moderate- and best-case scenarios are when the minimum and maximum savings are achieved by telework. This study uses scenario analysis and collects data from the databases of the Government of Canada for different domains of telework. The data includes commuting distances, electricity and natural gas consumption for offices and residential buildings, and ICT usage. Then, the associated GHG emissions are calculated for transportation, residential and office buildings, and ICT and the analysis are carried out by applying a potential fraction of saving to the associated GHG emissions of each domain in each scenario. This paper demonstrates that the potential energy savings of teleworking significantly depends on teleworker behavior to a degree that in the worst-case scenario no potential saving is observed while the savings are significant in the best-case scenario. Therefore, the impact of telework is extremely uncertain and complicated and current statistics are insufficient for accurate estimates.