Building Retrofit ECM Selection Using Group Knapsack Algorithm
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Solution Overview
Problem
Existing methods for determining Energy Conservation Measures (ECMs) in building retrofitting face challenges due to an excessively large number of combinations, making it difficult to find an optimal set that maximizes energy savings within cost constraints, and struggle to prevent duplicate selection of detailed measures.
Innovation Solution
An analysis apparatus and method that uses a group knapsack algorithm to select a maximum of one detailed measure from multiple options for each ECM, ensuring no duplicates are selected, and prioritizes cost-effectiveness by sorting candidate detailed measures based on energy savings and cost, using a dynamic programming table to optimize ECM selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of ECM combinations is increased to provide more selection options, then the versatility of ECM selection is improved, but the calculation time and complexity increase exponentially
Solution Approach 1:
The patent segments the ECM selection problem into two distinct phases: (1) generating candidate ECMs by selecting at most one detailed measure from each ECM group, and (2) filtering optimal candidates using the knapsack algorithm based on budget constraints. This segmentation reduces the computational burden by avoiding exhaustive enumeration of all possible combinations while maintaining solution optimality.
Solution Approach 2:
The patent transforms the original combinatorial optimization problem into a constrained selection problem by introducing the parameter 'at most one detailed measure per ECM group'. This parameter change fundamentally alters the search space from exponential to polynomial complexity, enabling efficient calculation while preserving the ability to provide diverse ECM selection options.
2Reliability
If all possible ECM combinations are considered to ensure optimal selection, then the energy savings optimization is improved, but the device complexity and computational resources required increase
Solution Approach 1:
The patent extracts and removes redundant combinations from the search space by enforcing the constraint that at most one detailed measure can be selected from each ECM group. This extraction eliminates duplicate and invalid combinations before applying the knapsack algorithm, ensuring optimality while significantly reducing computational complexity and resource requirements.
Solution Approach 2:
The patent performs preliminary filtering of ECM candidates before applying the optimization algorithm. By pre-selecting valid combinations that satisfy the 'at most one detailed measure per group' constraint, the system prepares a reduced candidate set that guarantees optimality when processed by the knapsack algorithm, avoiding the need to evaluate all possible combinations.
3Loss of energy
If detailed measures for multiple ECMs are selected independently to maximize energy savings, then the energy conservation effectiveness is improved, but the probability of duplicate selection increases
Solution Approach 1:
The patent applies preliminary anti-action by preventing duplicate selection of detailed measures across different ECM groups before the optimization process begins. The constraint 'at most one detailed measure per ECM group' acts as a preventive mechanism that eliminates the possibility of duplication, ensuring that each selected detailed measure is unique while still maximizing energy savings within the budget constraint.
Data Source
AI summary
A method and apparatus for determining an Energy Conservation Measure (ECM) for building retrofit. An analysis apparatus receives a condition for building retrofit, and selects detailed measures of one or more Energy Conservation Measures (ECMs) for a building based on the condition. The analysis apparatus selects a maximum of one detailed measure from among multiple detailed measures of each of the one or more ECMs. The analysis apparatus provides one or more ECM determination schemes, which include an energy savings-based ECM determination scheme and a cost-based ECM determination scheme.