Method for the economic profitability of energy rehabilitation operations: application to residential dwellings in Seville

Abstract

This work proposes a method based on a computer model to assess the economic profitability of energy rehabilitation operations in the envelope of a block of residential dwellings (Virgen del Carmen) in Seville (Southern Spain). The work evaluates the influence that certain hypotheses of interventions in the opaque part of the envelope exert on the annual energy demand: better insulation of the façade, interior partitions, roof and ground floors, in addition to its semi-transparent part: improvements in the airtightness of the building openings, the glass windows, and the thermal conductivity of its frame. These interventions arise from strict compliance with the Spanish regulatory framework. This model has been designed for the context of a Mediterranean climate, (mild winters and hot summers). The simulation tool Design Builder 3.4.0.041, which uses the calculation engine Energy Plus 8.1, has been selected to generate the computing model and establish its energy demand. The amortization of the economic costs of rehabilitation is quantified by the net present value (NPV) index, in accordance with the savings in the bills of energy consumption due to the reductions in demand for heating and cooling in the building, thereby obtaining an amortization period which exceeds 22 years