rebound effects in heating energy demand after thermal...
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Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Rebound effects
in heating energy demandin heating energy demand
after thermal refurbishment
of apartment buildings
DI Petra Johanna Sölkner
Petra Johanna Sölkner
Bautechnisches Institut Linz
Ardeshir MahdaviTechnical University Vienna
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Main ResearchMain Research ServicesServices
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DI Petra Johanna Sölkner
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Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
1. Introduction
→ Energy Effciency - Why?
Content
EconomicsEnergy politics
Introduction Direct Rebound Effects Project Analysi s Important Factors Summary
→ Energy Effciency - Why?
→ The Building Sector
→ Definition of Rebound Effect (RE)
→ Direct Rebound Effect
2. Results
→ Analysis of 27 Projects
→ Extent of RE
Energy politicsEnergy economicsEnergy efficiency
Scientific literaturE-Journals
Project reports
DI Petra Johanna Sölkner
4. Important Factors to limit the Extent of RE
5. Summary
Project reportsMaster thesis
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
High dependency on imports of energy (esp. fossile fuels)→ 70 % in EU (2020–2030); 62 % in AT (2010)
Energy Efficiency in the Building Sector
Introduction Direct Rebound Effects Project Analysi s Important Factors Summary
→ 70 % in EU (2020–2030); 62 % in AT (2010)
Global warmingEnergy policy : demand control → consumer behavior and energy efficiency
Building sector→ 36 % of CO2 emissions
→ 40 % of final energy consumption
→ 68–79 % final energy consumption of private households for space heating (AT)
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Effiziency potentials : buildings up to construction year 1960 → 60 – 90 %
buildings up to construction year 1970 → 30 – 40 %
Dependend on→ Type of building
→ Status before retrofit
→ Level of thermal retrofit
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
A rebound effect is the cushioning of desired, introduced processes and the diminishing of their effects by different mechanisms.
The Rebound Effect
Introduction Direct Rebound Effects Project Analysi s Important Factors Summary
and the diminishing of their effects by different mechanisms.(Translation from Langenscheidt)
Example: Increasing energy effiency
� Single measure
� Politically initiated efficiency programms
Expected energy savings [kWh/a] … 100 %
DI Petra Johanna Sölkner
Expected energy savings [kWh/a] … 100 %
Realised energy savings … 70 %
Not realised savings = Rebound effect … 30 %
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Direct Rebound Effect � Primary Effect
Direct Rebound Effect I
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
Direct Rebound Effect � Primary Effect
– regarding final energy demand (energy services, e.g. space heating)
– occurs immediately, primarily, directly
DI Petra Johanna Sölkner
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Reduction factor & Comfort factor (Hamilton et al. 2011)
Direct Rebound Effect II
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
DI Petra Johanna Sölkner
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Results of Project Analysis I
Rebound effect in [%]
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
Rebound effects
Project reports
–17 % to +25 %
Master thesis Scheer P. (1996)
0 % to +61 %
[%]
DI Petra Johanna Sölkner
0 % to +61 %
Planned savings in heating energy demand in [%]according to basic value before thermal retrofit
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Rebound effects in dependency of heating energy consumption before thermal retrofit
Results of Project Analysis II
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
MARESI study Project analysis
RE [%]RE [%]
Basic values beforethermal retrofit [kWh/m2a)
DI Petra Johanna Sölkner
Theoretical savings in heating energyrelating to basic value before thermal retrofit [%]
Theoretical savings in heating energyrelating to basic value before thermal retrofit [%](Biermayer et al. 2005)
No basic value
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Drastically varying specific heating energy consumption of different households in the same building.
Results of Project Analysis III
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
Example: Energetic building refurbishment by factor 10
Multy storey building, Jean-Paul-Platz, Nürnberg (GER)
Specificheating energy consumption
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(Schulze Darup et al. 2005)
consumptionafter thermal retrofit[kWh/m2a]
Appartment No.
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Building
� Maximum level of retrofit
Important Aspects for Retrofit I
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
� Maximum level of retrofit
→ thermal bridges minimised
→ air & wind tightness
→ insulation of heat distribution pipes
� Avoiding lock-in effects on energy efficiency potentials
DI Petra Johanna Sölkner
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
HVAC systems
� Avoid complex systems
Important Aspects for Retrofit II
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
� Avoid complex systems
� Optimised planning of HVAC system
� Adopted building equipment
→ quality assurance of the systems
→ hydraulic balance
→ optimised heating curve
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→ heating system driven by ambient temperature
� Combined fresh/exhaust air ventilation system
→ heat recovery system
→ minimum (hygienic) air change rate
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Control systems
� Coupling heating & ventilation system by window contacts
Important Aspects for Retrofit III
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
� Coupling heating & ventilation system by window contacts
� Limiting permitted indoor temperature
� Control system
→ indoor temperatur, air change rate
→ easily operated
→ energy consumption control in real-time
DI Petra Johanna Sölkner
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Users
� Involve dwellers into the retrofitting process
Important Aspects for Retrofit IV
Introduction Direct Rebound Effects Project Analysis Important Factors Summary
� Involve dwellers into the retrofitting process
� Explanation about the new situation
� User training
→ control elements
→ adequate ventilation habits
→ continuous & long-term
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→ individual & direct
� Energy billing
→ direct, clear, in-time
→ no lump-sum!!
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Summary
Energy saving potentials for single object between 30 – 90 %
Introduction Direct Rebound Effects Project Analysis Important Fa ctors Summary
Energy saving potentials for single object between 30 – 90 %� should be put into effect!
Direct rebound effects arise mainly from:
User habits Technical aspects
– chosen temperature – building
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– ventilation behavior – HVAC system
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Summary
Three pillars for restricting rebound effects:
Introduction Direct Rebound Effects Project Analysis Important Fa ctors Summary
1. Increasing energy efficiency
Optimised and adopted HVAC
2. Demand control / restriction of energy consumption
Maximised quality of retrofitting
Minimised potentials for dissipation of energy
DI Petra Johanna Sölkner
Higher prices for energy
3. Awareness raising
Information and training of the users/habitants/dwellers
Rebound effects in heating energy demand
after thermal refurbishment of apartment buildings
Thank you for your attention!
DI Petra Johanna Sölkner