Computational Tools for Energy Efficiency: Case of Building Renovation

Venkata BandiDepartment of Energy Technology

Outline

• Building renovation relevance to energy efficiency• Renovation process

– Focus of this presentation

• Computational tools– Simulation and Calculation

• Compliance analysis• Conclusion

Building Renovation Importance

Source : OTB Research Institute for Housing, Building Renovation and Modernisation in Europe: State of the art review, Delft University of Technology, 2008

Energy Efficiency Potential

Building Renovation Importance

Energy Efficiency in the Context Buildings• Performance Indicators

– vary significantly across disciplines

• Improvements Initiatives– Several alternatives

System Boundaries of the Building

Building Renovation

Source: Yin H. and Menzel, K., Decision Support Model for Building Renovation Strategies,” in International Conference on Building Science and Engineering, 2011.

Initial survey

Energy performance evaluation

Possible solutions

Focus

DecisionProcesses

Source: Yin H. and Menzel, K., Decision Support Model for Building Renovation Strategies,” in International Conference on Building Science and Engineering, 2011.

Feasibility analysis

Existing Approach to Renovation

• Past experiences and common practices– It can go wrong with changing habits resulting from

technological advancements – Buildings are unique

• Location, marker value etc..

Contd..

Computational tools for Decision Support for Buildings

Early Stages of Renovation

• Decision makers– Building owners, Real-estate companies, Urban planners,

Architects

• Alternative to existing practices– Use of computational tools

• Decision-aid for feasibility analysis

Feasibility analysis

• A feasibility study is a technical and economic analysis of potential energy savings– Identifies technical and economical impacts

• Provides reviewers with sufficient information to judge the technical and economic feasibility of the recommended alternatives

Compliance of Computation Tools

• Assumptions– Access to basic geometrical details about the building envelope,

but not extensive details – Basic understanding of technical and economic aspects of

energy efficiency initiatives and indicators – Limited financial resources during conceptual stage of

implementing different energy efficiency measures – Very strong co-relation between input-data size, cost associated

with data collection and effort required for data organization

What are calculation tools?

• Mathematical model– Simple linear equations

• Data analysis– System level aggregation

Example 1

• Additional insulation and energy savings

Compatibility of Computation Tools

• Simulation tools– Demands expertize– Meant for experts

• Calculation tools– Basic skills enough– Suits early decision-making

• Use of calculation tools in early-stage decision-making – Promotes energy efficiency objectives– Increases possibilities of selecting best alternative at early-

stages– Feasibility analysis

Downsides of Calculation Programs

• Our Experience– Finding appropriate supporting tools for early stage decision-

making is a challenging task

– There exists a great deal of variation across different calculation programs and the way impacts are calculated.

Suggestions

Calculation tools, which consider the following parameters, are relatively useful for early stage decision-making.

1. Climatic conditions2. Bundling of energy efficiency measures 3. Economic analysis4. Comparative analysis of different energy

efficiency measures