• Energy Research

Lifecycle cost analysis (LCCA) is a tool to assess the costs associated with each phase of the building lifecycle. This study evaluated the lifecycle cost (LCC) of a prefabricated fiber-reinforced composite (FRC) building in comparison with a masonry one. The four lifecycle phases of construction, operation, maintenance, and demolition were taken into consideration, and buildings in the American cities of El Paso, Los Angeles, and San Francisco were analyzed. First, the contribution of different building components to construction cost was defined. Consequently, the operation costs to supply cooling and heating-energy demands and lighting and home appliances were calculated. After determining the maintenance and demolition costs, the total LCC of both building types were compared through net present value (NPV). Finally, sensitivity analyses were carried out to assess the impact of influential parameters. The results highlight the significance of construction cost for both structures and the higher maintenance and lower demolition costs of the prefabricated building. Moreover, the prefabricated building was found to have higher cooling costs despite its lower U-value. The prefabricated building had a higher total LCC in all locations. The results also demonstrate the importance of location by indicating substantial variations in construction, maintenance, and demolition costs among the studied cities. Furthermore, the prefabricated building was found to have lower operating costs in Los Angeles and San Francisco but higher costs in El Paso. The sensitivity analyses show significant impacts of the discount rate and lifetime, moderate influence of the inflation rates of maintenance and demolition costs, and limited impact of the inflation rate of electricity cost.

Abstract Pre-fabricated composite buildings are proposed as sustainable sheltering and housing solutions for developing countries. This work compares different passive cooling techniques of shading, natural ventilation, cool painting and increase in thickness of interior gypsum plaster for these buildings to tackle overheating in hot climates. The studied techniques are measured and compared in terms of indoor air temperature by calculating four indicators of maximum, minimum, average of highest 5% and average of lowest 5% temperatures as well as thermal comfort of the occupants based on two acceptability rates of ASHRAE 55 and three acceptability limits of EN 15251 standards in three climates: Porto, Nairobi and Mumbai. The findings of this comparison bring insights into the effectiveness of passive cooling techniques, that can be highly beneficial at design level. Results point out improvements by all studied techniques, even if these quantitatively depend on the presence of the occupants and the choice of the performance indicators. Finally, further indicators such as stored heat, solar radiation heat gain and surface temperature are analyzed, to explain causes and effects associated with studied passive cooling techniques. Results of these comparisons pointed out that the combined implementation of all techniques combined is effective enough to provide thermal comfort of the occupants during almost all annual occupancy in Nairobi measured by acceptability rate of 80% of ASHRAE 55 and Category III of EN 15251.

Solid-state electrolytes are a promising family of materials for the next generation of high-energy rechargeable lithium batteries. Polymer electrolytes (PEs) have been widely investigated due to their main advantages, which include easy processability, high safety, good mechanical flexibility, and low weight. This review presents recent scientific advances in the design of versatile polymer-based electrolytes and composite electrolytes, underlining the current limitations and remaining challenges while highlighting their technical accomplishments. The recent advances in PEs as a promising application in structural batteries are also emphasized.

Abstract Material selection is a key step in product design and typically aims at identifying the most suitable material that meets product performance goals at minimum cost. In recent years research has been driven for developing sustainable solutions at competitive costs. This work evaluates the sustainability of advanced sandwich-structured composites for novel housing solutions. Five polymer matrix composite sandwich materials have been selected and compared concerning mechanical, thermal, acoustic and fire performance as well as cost and environmental impact, in order to study both the technical viability and the sustainability of lightweight solutions for prefabricated structural wall panels as well as for new housing; this included mechanical and fire testing of the selected materials. Subsequently, the thermal and acoustic properties of the alternatives were obtained. After performing a cost analysis and environmental assessment, the results of the tests and analyses led to a multi-criteria decision analysis (MCDA); PROMETHEE II (preference ranking organizational method for enrichment evaluation) was used to identify the best alternative. Finally the proposed solution was compared with a typical brick house performance. Higher specific strength, better thermal insulation and lower environmental impacts arose as the main advantages of the proposed structures while acoustic properties and fire safety still need to be improved.

Abstract This work provides a comprehensive approach for electrification of rural areas of Kenya through taking into account both energy demand and supply sides. Toward this, a pre-fabricated composite building is assessed by defining two different levels of energy needs and calculating annual cooling and heating energy demands to keep the occupants within the comfort temperature range. Consequently, four passive cooling techniques (shading, natural ventilation, cool painting and increased thickness of interior gypsum plaster) are applied to decrease the cooling energy demand. Afterwards, a stand-alone photovoltaic (SAPV) system is designed through sizing of the main components as well as determining the optimum tilt angle and azimuth for the PV array. Finally, four PV technologies (monocrystalline silicon (mono-Si), polycrystalline silicon (poly-Si), cadmium telluride (CdTe) and copper indium selenide (CIS)) were assessed for the designed SAPV system and compared in terms of environmental impact and cost and CIS demonstrated the best performance in all criteria. The results highlight a reduction of about 84% in cooling energy demand through combining all passive cooling techniques originating a house displaying passive behavior. Moreover, the SAPV system proves to be a feasible solution with significant lower cost and greenhouse gas (GHG) emissions in comparison with alternative solutions. The results also outline the importance of the loss of load probability (LLP) in designing SAPV systems indicating a sudden increase in required power of array for LLPs less than 2%.