Abstract
Studying energy renovation of older residential building stocks together with the surrounding district heating (DH) system is essential to fully understand implications from a reduced district heat demand and for involved actors. This study reveals the benefit of integrating the simulation and optimization tools OPERA-MILP, IDA ICE, and MODEST to investigate thoroughly the effect of energy renovation strategies on heat load supply, building and DH system-based life cycle costs (LCCs), primary energy use, and total of direct and indirect CO2 emissions. Energy renovation considered different cluster combinations of slab and tower blocks of a stock of 343 apartment buildings in two Swedish municipalities and strategies for lowest LCC and code compliance. Applied tools were thoroughly validated and verified including heat demand and load duration curves and numerical accuracy. Results with all aggregated clusters and renovation strategy for code compliance showed a reduced combined heat and power production with 35.7 GWh/a (heat) and 6.5 GWh/a (electricity), deceased primary energy use with 36.2 GWh/a and reduction of marginal CO2 emissions with 8.4 kton/a mainly from released biofuels substituting for fossil fuels in power plants, increased CO2 emissions of 0.5 kton/a with electricity production mix, and financial deficit for building owners, energy companies, and industries of respective 44, 33.9, and 2.2 M€/50a.
Highlights
The efficient use of energy in the European Union (EU) is a main topic to protect the environment, mitigate climate change, and reduce reliance on external supplies
Residential buildings represent with 76% the majority of the EU stock measured as total floor area, around 81% of their energy use corresponds to space and water heating, and half of the buildings in Abbreviations: BBR, Swedish National Board of Housing, Building and Planning’s mandatory provisions and general recommendations; CCP, coal-condensing power plants; CHP, combined heat and power; DH, district heating; DHW, domestic hot water; EEM, energy efficiency measure; EPC, energy performance certificate; EU, European Union; IDA ICE, IDA indoor climate and energy; LCC, life cycle cost; LPG, liquefied petroleum gas; MODEST, model for optimization of dynamic energy systems with time-dependent components and boundary conditions; natural gas combinedcycle condensing power plants (NGCC), natural gas combined-cycle condensing power plants; OPERA-MILP, optimal energy retrofits advisory-mixed integer linear program
DH system operations are output data given by MODEST and based on cost-optimal combinations of heat supply sources
Summary
The efficient use of energy in the European Union (EU) is a main topic to protect the environment, mitigate climate change, and reduce reliance on external supplies. Residential buildings represent with 76% the majority of the EU stock measured as total floor area, around 81% of their energy use corresponds to space and water heating, and half of the buildings in Abbreviations: BBR, Swedish National Board of Housing, Building and Planning’s mandatory provisions and general recommendations; CCP, coal-condensing power plants; CHP, combined heat and power; DH, district heating; DHW, domestic hot water; EEM, energy efficiency measure; EPC, energy performance certificate; EU, European Union; IDA ICE, IDA indoor climate and energy; LCC, life cycle cost; LPG, liquefied petroleum gas; MODEST, model for optimization of dynamic energy systems with time-dependent components and boundary conditions; NGCC, natural gas combined-cycle condensing power plants; OPERA-MILP, optimal energy retrofits advisory-mixed integer linear program.
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