Retrofitting Residential Gated communities for Net Zero Energy Housing in Greater Cairo

Abstract

Net Zero Energy Building (NZEB) concept is the future international goal for saving energy. NZEB concept has risen in many countries policies and worldwide discussions targeting efficient built environment.

In Egypt, the built environment consumes more than 70.1% of the total sold energy; the residential sector alone consumes 54.9%. According to the Egyptian annual electricity and renewable energy consumption report, "the increase in the rate of sold energy of the residential sector, in comparison with industry and other purposes, is a result of the expansion of residential compounds and new communities”. In this regards, this research aims at introducing the concept of retrofitting existing gated communities in order to achieve zero-energy community (ZEC). The research discusses the integration of two strategies: energy efficiency retrofitting techniques to reduce energy demand, and renewable energy systems to generate sufficient energy, which would result in an annual net zero energy consumption.

Design Builder simulation software is used to analyze the feasibility of integrating these two strategies in a single family house, as a part of a residential gated community located in the east of Greater Cairo. The simulation goes through two stages, the first stage concludes three phases, in which the first phase the actual energy performance and the user’s electric consumption patterns were determined in four main orientations in the community layout, to identify the maximum annual energy consumption . Three energy efficiency retrofitting techniques such as; insulation and glazing in the building envelope, and retrofitting of lighting systems, are investigated in the second phase aiming to reach the maximum energy reduction. In phase three renewable energy sources such as PV panels and solar thermal techniques are integrated to generate enough energy to cover the remaining energy from phase two. For the second stage, the simulation results of the first stage are implemented on the whole gated community (the community scales) aiming to reach zero energy consumption. The comparative analysis of simulation is used to determine how specific techniques lead to energy reductions in the second phase and energy production in the third phase.

The results achieved a reduction of 88.68% in energy consumption for the whole gated community, and prove that Net Zero Energy Building (NZEB) could be met by applying the appropriate energy efficiency retrofitting techniques, and the use of renewable energy systems. Moreover, a significant reduction in energy is shown when applying (NZEB) retrofit on a community scale (ZEC) than on a building scale. The previous strategies and methodology can be applied on other gated communities, in order to enhance the energy performance of existing buildings.