COST EFFECTIVENESS IN HVAC BY BUILDING ENVELOPE OPTIMIZATION

Abstract

The increased need for thermal comfort in buildings has increased the energy demand for HVAC systems. Building envelope and air conditioning system are closely interrelated; hence building envelope optimization should be the most crucial step towards HVAC load reduction. Building envelope optimization for minimizing heat gains and resultant energy demand involves optimization of building orientation, window-to-wall ratio (WWR), roof, wall, glass and shading devices. This study considers a Net Zero energy Home, a building that matches on-site energy production (through renewable sources such as solar photovoltaic) with on-site energy consumption, located in Delhi (India). For the purpose of analysis a simulation model of the building, created on eQuest energy analysis software, was run parametrically with incremental improvement in envelope parameters to evaluate their impact on building envelope load. The study revealed that, starting from a conventional base model to optimized design case, through step-by-step optimization of building orientation, window-to-wall ratio (WWR), roof, wall, glass and shading devices, percentage reduction in heat load through envelope was approx. 71%. This reduction resulted in lower HVAC load, thus a smaller energy efficient HVAC system was able to cater to the cooling/heating needs of the house.