Search

Abstract The growing demand for energy and the accelerating threats from climate change call for innovative and sustainable solutions to decrease dependency on fossil fuels. Biomass-based, small-scale Combined Cooling, Heating and Power (CCHP) systems are one of these solutions, because they can satisfy the energy demands of the consumer with enhanced flexibility, lower losses, less costs and less environmental pollution as compared to centralized facilities. Due to recent advances in several scientific subfields with relevance to small-scale CCHP, a rapidly increasing amount of literature is now available. Therefore, a structural overview is essential for engineers and researchers. This paper presents a review of the current investigations in small-scale CCHP systems covering biomass-fired concepts and solar extensions. To this end, critical system components are described and analysed according to their specific advantages and drawbacks. Recent case studies have been collected and key findings are highlighted according to each type of prime mover. The results indicate a scientific bias towards the economic viability of such systems and the need for real-life and experiment system data. However, the potential of biomass-fired CCHP systems and of such systems with solar extensions has clearly been recognised. Based on the results, future policy implementations should focus on fostering such systems in areas with high energy costs and to increase energy resilience in developed regions. Additionally research and industry applying novel prime mover technologies should be financially supported. Highlights • Small-scale, biomass-fired CCHP is gaining interest in science and industry. • Summary on biomass conversion, prime mover and cooling technologies. • The findings are put into context with current and future technology trends. • Entrepreneurial bias of scientist towards feasibility of CCHP systems. • Policies should promote CCHP in areas with high energy costs and low grid stability. [ABSTRACT FROM AUTHOR]

This contribution deals with flexographic printing of nanoparticulate tin-doped indium oxide (ITO) inks for the manufacture of fine lines on PET foils and glass substrates. The development and optimization of ITO inks, based on solutions of water and ethanol, for the flexographic printing process is presented. The influence of the solvent composition, of the particle content, and of the molar mass of the binder polyvinylpyrrolidone on the printing result is shown. ITO lines with a minimum line width of around 120 μm were printed using a printing plate with a feature size of 50 μm; the ITO lines exhibited a thickness of around 1 μm. Laser post-treatment was used to consolidate the top layer of the nanoparticulate ITO structures resulting in improved electrical properties; low sheet resistance values of around 300 Ω/□ were achieved. [ABSTRACT FROM AUTHOR]

This paper presents the manufacture of ultrathin (<1 µm) transparent conductive indium tin oxide (ITO) films based on nanoparticulate ITO slurries by the profile rod technique using the binder polyvinyl pyrrolidone (PVP) as an organic additive. The influence of the slurry composition on the film thickness and the specific electrical resistance as well as the transmission of the dried films is evaluated. The organic solvent ethanol and different types of the PVP binder were tested for slurry preparation and layer performance. ITO green films with low specific electrical resistance of 3 Ω cm, 87 % inline transmission, and layer thicknesses of only 250 nm could be manufactured. Furthermore, the influence of heat treatments up to 400 °C on the electrical properties of the ITO films was evaluated. [ABSTRACT FROM AUTHOR]

This paper presents the development of nanoparticulate indium tin oxide (ITO) inks for the continuous manufacture of ultrathin (∼280 nm) ITO layers on PET substrates by roller coating at very high coating speeds. Ethanol- and water-based ITO inks containing polyvinylpyrrolidone as binder were prepared and rheologically characterized. The influence of different ink compositions on coating properties was evaluated by the concept of the dimensionless capillary number Ca. The ITO films were characterized concerning optical and electrical properties in dependence on ink composition and coating parameters. The organic solvent ethanol could be replaced by water, being cheap and environmental friendly. These inks allow the manufacture of sub-μm thin ITO layers with high layer quality and low specific electrical resistance of 3 Ω cm. Flexible and highly transparent ITO films with an inline-transmission of 88% in the regime of visible light which absorbed simultaneously up to 96% in the NIR region were produced. [ABSTRACT FROM AUTHOR]

This paper discusses the gelation of polyvinylbutyral (PVB) solutions by the addition of tetrabutyl orthotitanate. The addition of around 0.10 vol.% tetrabutyl orthotitanate to an ethanol-based PVB solution already causes a pronounced gelation. For the characterization of this gelation reaction, different rheological measurements are used. The characterization is mainly performed in the linear viscoelastic regime. Time sweeps prove the stability of the samples during the measuring time. Frequency sweeps are used to investigate the state of gelation after different reaction times as well as the dependence of the degree of the gelation on the tetrabutyl orthotitanate concentration. Furthermore, the gelation point is determined by measuring the loss factor tan δ as a function of frequency. A strong influence of water on the degree of gelation is shown; by the addition of different amounts of water, the gelation can be controlled or even avoided. Amplitude sweeps reveal the breakdown of certain network structures at high amplitudes which recover after the strain is lowered. [ABSTRACT FROM AUTHOR]

Paired electrolysis offers an auspicious strategy for the generation of high‐value chemicals, at both the anode and cathode, in an integrated electrochemical reactor. Through efficient electron utilization, routine product misuse at overlooked electrodes can be prevented. Here, an original paired electrosynthetic system is reported that can convert CO2 to ethylene (C2H4) at the cathode, and water to hydrogen peroxide (H2O2) at the anode under a single pass of electric charge. Amongst various investigated copper (Cu) nanomorphologies, the bespoke mixed Cu nanowire/nanoparticle catalyst recorded a peak C2H4 Faraday efficiency (FE) of 60% following 370 h of electrolysis at 200 mA cm−2, while the tailored boron‐doped diamond (BDD) anode accumulated an unprecedented ≈1% w/w of H2O2 in 4 m K2CO3 upon applying 300 mA cm−2 for 10 h. When paired, the dual C2H4‐H2O2 electrochemical cell attains a combined FE of 120% for 50 h at 200 mA cm−2, a combined energy efficiency (EE) of 69%, and a 50% decrease in the overall electrical energy consumption (EEC) compared to the individual electrosynthesis of C2H4 and H2O2. [ABSTRACT FROM AUTHOR]

Renewable energy polygeneration systems are a viable alternative to fossil-fuel based systems, but storage solutions may be necessary when aiming for high sustainability and autonomy. As each storage technology has different strengths and weaknesses, combinations of various storage solutions may lead to better techno-economic performance than singular approaches. To this purpose, an optimization model including a novel dispatch control strategy for a hybrid energy storage system (HESS) is proposed, which uses biogas for long-term and batteries for short-term storage. The model optimizes for minimum lifetime costs while exploiting the biomass resources with maximum efficiency and quantifying the additional solar and battery capacities needed. It is applied in a case study with an innovative biomass-based polygeneration system in a rural locality of Bolivia to serve electricity, potable water, and bio-slurry as fertilizer. The results indicate that even with maximized efficiency of the biomass resource conversion, large PV and battery capacities are necessary to satisfy the electricity demand of the locality. Despite of the high investment costs, the biomass-based polygeneration system would cost 22% less over the project lifetime than the fossil-fuel based reference system while being less dependent on fuel price changes. It would also reduce CO 2 -emissions by over 98%. • Presenting a control strategy for polygeneration systems using biogas and batteries • Development of a model for such systems enhanced with PV and membrane distillation • Application of the model in a case study for a rural locality in Bolivia • Results show 22% lower lifetime costs and 98% less emissions but high capital costs • The model including the control strategy facilitate designing polygeneration HESS [ABSTRACT FROM AUTHOR]

• Cost-optimal design method for CCHP-assisted HP systems for varying climate scenarios. • Numerical transient model for demand and CCHP/HP system analysis. • Techno-economic analysis of Montjuic Castle, Barcelona, based on the model. • Small CCHP leads to more sustainable autonomy without unreasonable extra costs. • Climate change has a relatively small effect on comparative economic performance. An innovative modelling approach for the design of biomass-based, solar-assisted combined cooling, heating, and power (CCHP) and heat pump (HP) systems for various climate scenarios is proposed in this work. The modelling approach is comprised of three sub-models (a demand sub-model, a supply sub-model, an economic sub-model) allowing for cost-optimal sizing of the system components based on net present cost (NPC). Subsequently a transient optimization model has been developed, which computes the technical and economic performance for each component size and for each ambient temperature of the different climate scenarios. Additionally, the model provides data on energy efficiency, exergy efficiency, and CO 2 -emissions of a given CCHP/HP system. The model has then been employed in a case study in order to analyse the performance of a CCHP/HP system for a tourist, museum, and guest accommodation structure located at the Montjuïc castle in Barcelona, Spain. The results show that the smallest simulated biomass-based CCHP system using a 25 kW e syngas-fuelled engine would reduce lifetime costs by 7% compared to an only-HP system while operating with a high total energy efficiency of over 60%. The combined CCHP/HP system would operate with an exergy efficiency of 18%. However, larger CCHP systems cannot offset the much higher capital costs despite increasing electricity sales. The findings also reveal that for the high climate change scenario the overall project costs drop by up to 2.5%, however the effects have little impact on the optimal CCHP/HP system sizing. Even the smallest CCHP system would reduce emissions already by 75% with an increasing trend for larger systems. Although CCHP/HP systems would lead to lower NPC and emissions, the high investment costs and the complexity of the combined system remain considerable obstacles. [ABSTRACT FROM AUTHOR]

Energy services are especially expensive on remote islands due to longer and more unstable fuel supply chains. In this paper, different renewable energy systems utilizing locally available biomass and solar energy are proposed as alternatives for a hotel resort on Neil Island, India. Based on local demand data, commercial information, and scientific literature, four cases are modelled with the simulation software HOMER and their economic, energetic, as well as ecological (3E) performances are compared. The robustness of each case configuration is tested with a sensitivity analysis. The results show that a biomass-based, solar-assisted combined cooling, heating, and power (CCHP) system offers an economic saving potential of more than 500,000 USD over twenty years and could decrease CO2 emissions by 365 t per year. When not applying CCHP measures, system performance is significantly worsened. A solar and battery-assisted diesel generator system shows similar economic outcomes as the CCHP system but worse ecological performance. Implementing the biomass-based CCHP system could improve the ecological footprint of the island, substantially decrease expenditure for the hotel owner, and generate a new source of income for surrounding farmers through biomass selling. [ABSTRACT FROM AUTHOR]

In an article published in Advanced Energy Materials, researchers describe a paired electrochemical reactor that can continuously produce ethylene and hydrogen peroxide. The reactor achieved a combined Faraday efficiency of 120% and an energy efficiency of 69% when operated at 200 mA cm−2 for 50 hours. Additionally, the reactor's overall electrical energy consumption was reduced by 50%. This research has implications for the sustainable production of chemicals and fuels using carbon dioxide reduction and water oxidation reactions. [Extracted from the article]

CO 2 reduction offers an attractive alternative green synthetic route for ethylene, especially where CO 2 could be sourced from industrial exhausts and in combination with green power sources. However, practical applications are currently limited due to the unfortunately low selectivity of cathode materials towards ethylene. This work uses polymers with intrinsic microporosity (PIMs) to improve the performance of copper gas diffusion electrodes for CO 2 reduction to ethylene. We report an improved selectivity and activity towards ethylene with the addition of a thin PIMs layer, which is seen as improved Faradaic efficiency, increased stability and a shift in the reduction to lower overpotential. This improvement is highly dependent on the thickness of the added polymer layer, with too thick a layer having a detrimental impact on the hydrophobicity of the gas diffusion layer. With a compromise in loading, PIMs can be used to enhance the activity and selectivity of catalysts for targeted CO 2 reduction to ethylene. Image 10694 • Gas diffusion electrodes allow CO 2 reduction to ethylene, but selectivity is low. • Polymers with intrinsic microporosity can increase ethylene production. • Using too much polymer has a detrimental impact. • A compromise polymer thickness increases ethylene yield and electrode stability. [ABSTRACT FROM AUTHOR]