Paper Conference

2018 Building Performance Analysis Conference and SimBuild co-organized by ASHRAE and IBPSA-USA


Tool For Energy Efficient Building Envelope Retrofitting

Bandana Jha, Dr. Bishwajit Bhattacharjee

Abstract: Buildings account for about one-third of all energy consumption in the world. A major source of heat ingress in existing-buildings is through the envelopes. A bulk of cooling load in existing-buildings can be reduced by energy-efficient retrofitting of Roof, Wall and Fenestration. The methods available for calculating heat ingress in large-scale existing structures are lengthy/cumbersome and manually impractical. The popular energy simulation software is black-box type requiring specialized technical skills, voluminous data-entries and does not automatically optimize/select the most energy efficient envelope retrofitting material out of available options in the local market. This paper proposes a user-friendly spread-sheet based model of a tool for automatically optimizing energy efficient envelope retrofit solutions from the available options in the local Market for existing buildings. The CIBSE admittance method is used for determination of thermal load of buildings. The developed model is used to find the most energy-efficient solutions for retrofitting of a 5-Star hotel at New Delhi with minimum heat ingress, minimum initial cost, minimum life-cycle cost and maximum Net Present Value. Cooling load has been primarily considered. To confirm the validity of proposed model, energy performance of the existing building envelope and selected retrofitting materials have been evaluated using eQuest. Results obtained confirm that the ratio of annual plant-load of existing and optimized solutions obtained through eQuest and proposed model are similar. The developed tool can help users select the right energy efficient envelope retrofitting materials to improve thermal comfort and reduce cooling-load in existing buildings
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