Evaluation of Environmental and Economic Sustainability for the Building Envelope of Low-Carbon Schools

To achieve a carbon-free economy by 2050, the construction of low-carbon schools in Italy must select the proper structural and technological solutions for the building envelope while ensuring a low economic cost. The aim of this study was to analyze and compare several technological solutions for the building envelope and the related structural solutions in terms of thermo-dynamic properties, energy performance, environmental sustainability parameters, and economic evaluations, to obtain one or more alternatives. After a general study, the binomial load-bearing structure–external wall was investigated given its strong influence on both the environment and the total cost. The solutions were used in a new typological model for the kindergarten. All the solutions are comparable from an energy and environmental point of view, obtaining a primary energy demand of <25 kWh/(m2year) and an environmental impact of <20 kWh/(m2year). However, considering the economic factor and analyzing the binomial load-bearing structure–external wall, the advisable solutions are those that use wooden structures with insulation layer in wood fiber as they have a significantly lower environmental impact, along with the same good energy performance and have an acceptable cost compared to other analyzed solutions

Techno-economic analysis of hydrogen production using biomass gasification. A small scale power plant study

Hydrogen has the potential to be a clean alternative to the fossil fuels currently used. This is especially true if hydrogen is manufactured from renewable resources such as biomass. However, hydrogen from biomass faces techno and economic challenges especially in the small size required for the decentralized hydrogen production. In this purpose, a techno economic analysis was carried out on small scale (100kWth) system. The plant is mainly composed of gasifier (double bubbling fluidized bed reactor) coupled with a Portable Purification Unit (PPS: catalytic filter candles, Water Gas Shift and Pressure Swing Absorption). This work focuses on system costs to identify barriers to the development of this technology. A sensitivity analysis was conducted to study hydrogen production cost as a function of capital cost, operating cost and hydrogen production efficiency. The results showed that although efficiency of the production system is the main factor to fall production cost, it cannot be able to reduce costs to favorable level alone. In other words, PPS cost recognized as the major cost is requisite to go down. Therefore, the 50% reduction of PPS cost and the variation of steam to biomass from 1 to 1.5 allow the special cost to fluctuate between 12.75-9.5 €/kg

Hydrogen-rich gas production by sorption enhanced steam reforming of woodgas containing TAR over a commercial Ni catalyst and calcined dolomite as CO2 sorbent.

The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR) and CH 4 and to produce pure H 2 by means of a CO 2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO). The bed material simultaneously acts as reforming catalyst and CO 2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH 4 removal, with conversions near 100%, while the simultaneous CO 2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO 2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO 2 during the duty cycle

design optimization of a distributed energy system through cost and exergy assessments

Abstract In recent years, Distributed Energy Systems (DESs) have been recognized as a good option for sustainable development of future energy systems. With growing environmental concerns, design optimization of DESs through economic assessments only is not sufficient. To achieve long-run sustainability of energy supply, the key idea of this paper is to investigate exergy assessments in DES design optimization to attain rational use of energy resources while considering energy qualities of supply and demand. By using low-temperature sources for low-quality thermal demand, the waste of high-quality energy can be reduced, and the overall exergy efficiency can be increased. Based on a pre-established superstructure, the aim is to determine numbers and sizes of energy devices in the DES and the corresponding operation strategies. A multi-objective linear problem is formulated to reduce the total annual cost and increase the overall exergy efficiency. The Pareto frontier is found to provide different design options for planners based on economic and sustainability priorities, through minimizing a weighted-sum of the total annual cost and primary exergy input, by using branch-and-cut. Numerical results demonstrate that different optimized DES configurations can be found according to the two objectives. Moreover, results also show that the total annual cost and primary exergy input are reduced by 20% - 30% as compared with conventional energy supply systems