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Abstract Thermal energy storage systems for both heat and cold are necessary for many industrial processes. High energy density and high power capacity are desirable properties of the storage. The use of latent heat increases the energy density of the storage tank with high temperature control close to the melting point. Tube in PCM tank is a very promising system that provides high packing factor. This work presents an experimental study of a PCM tank for cold storage applications. Two different configurations and different flow rates of the heat transfer fluid were studied. The effectiveness of the PCM storage system was defined as that of a heat exchanger. The results showed that the heat exchange effectiveness of the system did not vary with time, decreased with increasing flow rate and increased with increasing heat transfer area. The effectiveness was experimentally determined to only be a function of the ratio m ˙ /A. This equation was found to be adequately be used to design a PCM storage system, and a case study is presented. It was shown that the tube in tank design together with a low temperature PCM is suitable as a thermal storage facility for cold storage.

Central solar heating plants with seasonal storage (CSHPSS) are among the most promising technologies to save energy in the industrial and residential-commercial building sectors. This work introduces a systematic approach to optimize these systems according to economic and environmental criteria. Our method, which combines the TRNSYS 17 simulation software with life cycle assessment and multi-objective optimization, identifies optimal CSHPSS designs for any climatic condition and heating demand profile considering economic and environmental criteria simultaneously. The capabilities of this approach are illustrated through its application to a case study of a CSHPSS located in Barcelona (Spain), which satisfies a heating demand for a neighborhood of 1120 dwellings. Numerical results show that the CSHPSS plant leads to significant environmental and economic improvements compared to the use of a conventional natural gas heating system. Our tool can guide engineers and architects in the transition towards a more sustainable residential sector.

Abstract In the framework of the European project SSH2S, a solid-state hydrogen storage tank - fuel cell system was demonstrated as Auxiliary Power Unit (APU) for a light duty vehicle. In this work, we have assessed the environmental impacts and the costs of the system developed. Following an eco-design approach, we have identified the processes mostly contributing to them and we have suggested possible improvements. By performing a Life Cycle Assessment (LCA), we found that, when the electricity consumption for hydrogen gas compression is included into the analysis, a solid-state hydrogen storage tank has similar greenhouse gas emissions and primary energy demand than those of type III and IV tanks. However, the resources depletion is higher for the solid-state system, even though the inclusions of the end of life of the APU and the recycling of the materials may result in different conclusions. The costs of an APU equipped with a solid-state hydrogen storage tank are significantly higher, about 1.5–2 times the systems based on type III and IV tanks. However, mature technologies are compared with a prototype, which has much room for optimization. To improve both the environmental and economic performances of the APU, a reduction of structural materials for both the solid-state hydrogen tank and Balance of Plant is recommended.

Abstract Numerical modelling is commonly used to design, analyse and optimise tube-in-tank phase change thermal energy storage systems with fins. A new simplified two dimensional mathematical model, based on the effectiveness-number of transfer units technique, has been developed to characterise tube-in-tank phase change material systems, with radial round fins. The model applies an empirically derived P factor which defines the proportion of the heat flow which is parallel and isothermal. This P factor was determined using a validated computational fluid dynamics model. This method can be used to design and optimise tube-in-tank salt based phase change thermal storage units with finned tubes.

Vineyards cover about eight millions of hectares worldwide and their annual pruning generates a large amount of ligno-cellulosic biomass, potentially available for industrial and energy use. Commercial pruning residue harvesters are now available, which may allow cost-effective recovery. The study aimed at determining the quantity and the quality of pruning residues potentially derived from vineyard management. Data were obtained from 17 fields in Northern and Central Italy. Fields were harvested with seven different machines. The experimental design adapted to the necessities of field trials, but was adequate for testing the main sources of variability. Net residue yield varies around 1 oven dry tonne per hectare, with minor differences between grape varietals and harvesting technologies. Losses are still high, and are generally related to ineffective management techniques. Moisture content at harvest varies between 40% and 45%, whereas the higher heating value is slightly lower than that of forest fuels. Comminuted vineyard residues are unsuitable for firing residential boilers, due to the frequent presence of oversize and/or undersize particles. The application of pesticides does not result in any significant contamination with noxious chemicals, because these products are almost completely weathered before residues are recovered. In wine-producing regions, the recovery of vineyard pruning residue may represent a substantial source of industrial bio-fuel. © 2011 Elsevier Ltd.

About 72 million households in rural India do not have access to electricity and rely primarily on traditional biofuels. This research investigates how rural electrification could be achieved in India using different energy sources and what the effects for climate change mitigation could be We use the. Regional Energy Model (REM) to develop scenarios for rural electrification for the period 2005-2030 and to assess the effects on greenhouse gas emissions, primary energy use and costs. We compare the business-as-usual scenario (BAU) with different electrification scenarios based on electricity from renewable energy, diesel and the grid. Our results indicate that diesel systems tend to have the highest CO2 emissions, followed by grid systems. Rural electrification with primarily renewable energy-based end-uses could save up to 99% of total CO2 emissions and 35% of primary energy use in 2030 compared to BAU. Our research indicates that electrification with decentralised diesel systems is likely to be the most expensive option. Rural electrification with renewable energy tends to be the most cost-effective option when end-uses are predominantly based on renewable energy, but turns out to be more costly than grid extensions when electric end-use devices are predominantly used. This research therefore elaborates whether renewable energy is a viable option for rural electrification and climate change mitigation in rural India and gives policy recommendations. (C) 2009 Elsevier Ltd. All rights reserved.

Abstract This paper seeks to better understand how one plausible development in a green energy economy transition of the transport sector can be governed: a breakthrough of battery-electric vehicles (BEV). Drawing on recent results and lessons from BEV studies at local, national and regional scales, the paper presents two alternative scenarios of BEV uptake until 2030 – one incremental growth scenario and one breakthrough scenario. It then draws on the multilevel perspective (MLP) on socio-technical systems as an approach to identify the governance implications of the breakthrough scenario. Based on a characterisation of barriers and drivers at landscape, regime and niche levels, it identifies governance interventions to enable a BEV breakthrough. The results point towards a multidimensional governance approach that includes conventional policy instruments such as durable incentive policies, with a predictable mechanism for adjustment and phase-out, and mechanisms for mobilising investment finance for fast and super-fast charging and home charging along public roads. In addition, more innovation-systems oriented governance is required, such as familiarisation and experience building to ease cognitive barriers and build knowledge for both consumers and businesses, and supporting structural and technological change within automotive industries.

Promoting the use of solar photovoltaic (PV) systems in global cities can be an effective way to cope with severe environmental problems caused by the consuming of fossil fuels. However, a complex urban environment challenges the effective use of PV systems for practical applications. Essentially, this is a spatial optimization problem, where the goal is maximizing the harvesting of solar energy while minimizing occupied urban surfaces. To address this problem, this paper proposes three hierarchical optimizations. First, computational optimization provides a parallel architecture for an established 3D solar estimation model to achieve spatially scalable computation with high spatio-temporal resolution. Second, priority optimization determines the use of different urban partitions considering various constraints. Third, capacity optimization analyzes the spatial and quantitative distribution of solar potential, constrained by the smallest solar irradiation and the minimum surface area to be used. The overall optimization framework is then set to obtain the minimum PV installation capacity required to meet the real demand with the identification of urban surfaces to be equipped with PV modules. By using smart meter data with high temporal resolution in the city of Bologna, Italy, our analysis not only provides executable plans to meet the real demand but also reveals that rebalance and storage capacity are needed to achieve a real-time self-supportive architecture. The proposed analytic and optimization framework can promote distributed PV systems in urban areas and facilitate energy transition adapted to a variety of applications.