Reducing energy use in the buildings sector: measures, costs, and examples

Abstract

This paper reviews the literature concerning the energy savings that can be achieved through optimized building shape and form, improved building envelopes, improved efficiencies of individual energyusing devices, alternative energy using systems in buildings, and through enlightened occupant behavior and operation of building systems. Cost information is also provided. Both new buildings and retrofits are discussed. Energy-relevant characteristics of the building envelope include window-to-wall ratios, insulation levels of the walls and roof, thermal resistance and solar heat gain coefficient of windows, degree of air tightness to prevent unwanted exchange of air between the inside and outside, and presence or absence of operable windows that connect to pathways for passive ventilation. Provision of a high-performance envelope is the single most important factor in the design of lowenergy buildings, not only because it reduces the heating and cooling loads that the mechanical system must satisfy but also because it permits alternative (and low-energy) systems for meeting the reduced loads. In many cases, equipment with significantly greater efficiency than is currently used is available. However, the savings available through better and alternative energy-using systems (such as alternative heating, ventilation, cooling, and lighting systems) are generally much larger than the savings that can be achieved by using more efficient devices (such as boilers, fans, chillers, and lamps). Because improved building envelopes and improved building systems reduce the need for mechanical heating and cooling equipment, buildings with dramatically lower energy use (50-75% savings) often entail no greater construction cost than conventional design while yielding significant annual energy-cost savings.

Assessment of Energy Credits in LEED-Certified Buildings Based on Certification Levels and Project Ownership

“…The market and technical risks of the technologies used also contribute to the limited implementations resulting in fewer earned points. Still, significant savings in energy use in new buildings are possible using existing technologies [57]. The concerns also extend to non-economic barriers such as lack of technical expertise for advanced tools and services needed for improving energy efficiency.…”

Sensitivity Analysis of Building Envelop Elements Impact on Energy Consumptions Using BIM

“…From design parameter based LSA in previous section, the importance of design parameters to OE of building was understood and it was found that U-value of roof can be the priority target to reduce the OE of building as compared to other design parameters considered in this research, however this information may not result in an energy-efficient optimization process. This is due to EE of element is considerably increased during the optimization of building envelope while increasing the material consumption to satisfy the target thermal properties and reduce OE in buildings [2] [15] [32]. Besides, since the elements made up from different materials with its distinct thermal properties and each element comprised different proportion of EE in the building envelope, it is necessary to understand the uncertainty between thermal properties and EE of building envelope and subsequently the resulted OE-EE relationship of each envelope element.…”

Optimisation of Heat Loss through Ventilation for Residential Buildings

“…As confirmed by the analyses carried out by a number of authors [11,[28][29][30][31], 30 to 40% of the heat loss from residential buildings in various climatic conditions is discharged into the atmosphere together with the used air via the natural ventilation systems. In order to optimise the performance parameters of the ventilation system and simultaneously minimise heat losses via ventilation in a residential building, it is necessary to determine the unit heat flow driven out of the building together with the used air over one hour.…”