A multidisciplinary approach for an effective and rational energy transition in Crete Island, Greece.

This article proposes a mixture of actions for the development of an effective and rational energy transition plan for all sectors and for all types of onshore final energy use in Crete. Energy transition is initiated with an appropriate capacity building campaign. The plan is based on the introduction of energy saving measures and the exploitation of all the locally available energy resources (wind, solar, geothermal potential, biomass), integrated in a cluster of centralized and decentralized power plants and smart grids to produce electricity and heat and for the transition to e-mobility. The core of the energy transition in Crete will be a set of 14 wind parks and Pumped Hydro Storage systems (PHS) for electricity generation and 12 Combined Heat and Power plants, properly designed and dispersed in the insular territory. Economic analysis is executed for the proposed essential power plants on the island. Biomass, solar and geothermal potential can cover the heating demand in Crete several times. Heat can be produced with a specific cost of 0.05 EUR/kWhth from cogeneration plants fired with solid biomass and biogas. The wind parks-PHS systems exhibit payback periods of approximately 10 years with a final electricity selling price at 0.12 EUR/kWhel. The article shows that 100% energy transition in Crete constitutes a feasible target

Technoeconomic Analysis of the Recovery of Phenols from Olive Mill Wastewater through Membrane Filtration and Resin Adsorption/Desorption

Olive mill wastewater is an important agro-industrial waste with no established treatment method. The authors have developed a phenol separation method that could potentially cover the treatment cost of the waste. The purpose of this study was to identify any economic hotspots in the process, the operational cost and examine the margin of profit for such a process. The equipment cost was scaled for different treatment capacities and then used to estimate the fixed capital investment and the yearly operational cost. The highest purchased equipment cost was identified for the membrane filtration system, while the cost for resin replacement was identified as the highest operational cost. The lifespan of the resin used in the adsorption step was identified as an economic hot spot for the process, with the phenols separation cost ranging from 0.84 to 13.6 €/g of phenols for a resin lifespan of 5–100 adsorption/desorption cycles. The lifespan of the resin proved to be the single most important aspect that determines the phenols separation cost. The price range that was calculated for the product of the process is very promising because of the typical value of antioxidants and the low concentration of phenols that are needed for food supplements and cosmetics

Electricity supply on the island of Dia based on renewable energy sources (R.E.S.)

This paper presents a methodology for determining the specifications of an isolated R.E.S. power production system on an environmentally sensitive ecosystem. The wind and solar power constitute the primary power generation system and diesel generators act as backup. Real wind and solar potential measurements are used. The wind atlas of the island has been constructed. The specifications of the proposed system are optimized by the life cycle cost method. The renewable energy sources (R.E.S.) total annual energy production exceeds 90%. As a result, the dependence on the diesel generator set annual energy production is limited and the system's operational cost is not practically influenced by the increasing fossil fuel prices. The introduction of a small size desalination plant for the production of drinkable water is also investigated. Both the available R.E.S. potential and the minimization of environmental impacts are considered for the siting of the equipment. The methodology of the present paper may be applied to other regions rich in R.E.S. potential, where the introduction of small size environmentally friendly isolated R.E.S. power systems is investigated.Wind Photovoltaic Renewable Energy Power Hybrid

Energy upgrading of buildings. A holistic approach for the Natural History Museum of Crete, Greece

This article presents the fundamental points of the accomplished work regarding the energy upgrading of the building of the Natural History Museum of Crete, Greece, based on a cluster of passive and active measures. The main target was the building's energy efficiency upgrading from D to A+ rank. Among the passive measures, insulation of the building's envelope, installation of new windows and doors, construction of a green roof and planting of an outdoor space at the south side of the building to improve the ambient climate locally are included. Furthermore, small wind turbines and a photovoltaic station on the roof, geothermal heat pumps with an open loop system operating with seawater, new lighting equipment controlled by a central management system and reactive power coefficient compensation constitute the proposed active systems. Energy saving percentages from 40% to 93% are achieved with all the proposed technologies. In total, the primary energy specific consumption is reduced from 273.65 kWh/m(2) at 18.36 kWh/m(2), giving a total energy saving percentage of 93.29%. The building's energy efficiency is upgraded from the rank D to the rank A+, according to the European Union's standards. The total cost of the proposed measures is estimated approximately at 900,000

Liver ablation using a high intensity focused ultrasound system and MRI guidance

The effectiveness of magnetic resonance imaging (MRI) to monitor thermal lesions created by High Intensity Focused Ultrasound (HIFU) in rabbit liver in vivo is investigated. The MRI sequences of T1-weighted, and T2-weighted fast spin echo (FSE) were evaluated. The main goal in this paper was to find the range of repetition time (TR) and range of echo time (TE) which maximizes the contrast to noise ratio (CNR). An ultrasonic transducer operating at 2 MHz was used, which is navigated using a positioning device. With T1W FSE the range of TR under which CNR is maximized ranges from 400 to 900 ms. The maximum contrast measured is approximately 25. With T2W FSE the range of TE that establishes maximum contrast is between 40 ms and 80 ms, with CNR of approximately 14. T1W FSE is much better than T2W FSE in detecting thermal lesions in liver. Both T1W and T2 W FSE were proven successful to image thermal lesions created by HIFU in rabbit liver in vivo. ©2009 IEEE

Hydroxytyrosol Enrichment of Olive Leaf Extracts via Membrane Separation Processes

Antioxidants isolated from plant materials, such as phenolics, have attracted a lot of attention because of their potential uses. This contributes to the idea of the biorefinery, which is a way to produce useful products from biomass waste. Olea europaea byproducts have been extensively investigated for their large contents in phenolics. Oleuropein is a phenolic compound abundant in olive leaves, with its molecule containing hydroxytyrosol, elenolic acid, and glucose. In this work, olive leaf extracts were treated using different combinations of ultrafiltration and nanofiltration membranes to assess their capacity of facilitating the production of hydroxytyrosol-enriched solutions, either by separating the initially extracted oleuropein or by separating the hydroxytyrosol produced after a hydrolysis step. The best performance was observed when an ultrafiltration membrane (UP010, 10,000 Da) was followed by a nanofiltration membrane (TS40, 200–300 Da) for the treatment of the hydrolyzed extract, increasing the purity of the final product from 25% w/w of the total extracted compounds being hydroxytyrosol when membrane processes were not used to 68% w/w

High-Yield Production of a Rich-in-Hydroxytyrosol Extract from Olive (Olea europaea) Leaves

The aim of the present study was to explore the high-yield production of hydroxytyrosol, a phenolic compound with very high antioxidant capacity. Olea europaea leaves were chosen as feedstock as they contain significant amounts of oleuropein, which can be hydrolyzed to hydroxytyrosol. The chosen techniques are widely used in the industry and can be easily scaled up. Olive leaves underwent drying and mechanical pretreatment and extractives were transported to a solvent by solid–liquid extraction using water–ethanol mixtures. The use of approximately 60–80% ethanol showed an almost 2-fold increase in extracted phenolics compared to pure water, to approximately 45 g/kg of dry leaves. Extracted oleuropein was hydrolyzed with hydrochloric acid and the hydrolysate was extracted with ethyl acetate after pH adjustment. This step led to a hydroxytorosol content increase from less than 4% to approximately 60% w/w of dry extract, or 10–15 g of hydroxytyrosol recovery per kg of dry leaves

Recovery of Water from Secondary Effluent through Pilot Scale Ultrafiltration Membranes: Implementation at Patras’ Wastewater Treatment Plant

Fresh water shortages affect larger areas each year due to the increased human population combined with climate change. Reuse of treated sewage water (mostly for nonpotable uses) can have a significant impact on reducing water scarcity. Ultrafiltration membranes are widely considered as a very good candidate for the remediation of this type of water. The case of Patras’ sewage treatment plant was examined for the treatment of its secondary settling tank effluent using a pilot ultrafiltration unit to produce permeate water suitable for reuse according to Greek legislation. The physicochemical characteristics of the membrane permeate stream showed significant improvements in the quality of the produced water. Turbidity was reduced by 99%, total suspended solids were decreased by more than 94%, while COD was reduced by 37%. E. coli and Enterococcus were detected at high concentrations in the feed stream but were eliminated in the membrane permeate. The results presented herein indicate that the installed equipment is capable of producing improved quality water suitable for reuse even with the strictest limits imposed by Greek legislation

Penetration of high intensity focused ultrasound ex vivo and in vivo rabbit brain using MR imaging

In this paper magnetic resonance imaging (MRI) is investigated for monitoring the penetration of high intensity focused ultrasound (HIFU) ex vivo and in vivo rabbit brain. A single element spherically focused transducer of 5 em diameter, focusing at 10 em and operating at 2 MHz was used. A prototype MRI- compatible positioning device is described. MRI images were taken using fast spin echo (FSE). The length of the lesions in vivo rabbit brain was much higher than the length ex vivo, proving that the penetration in the ex vivo brain is limited by reflection due to trapped bubbles in the blood vessels. ©2009 IEEE