Design of a 5th Generation District Heating Substation Prototype for a Real Case Study

The evolution of district heating networks is moving toward low temperatures in heat distribution with so called 4th generation networks. However, the lowest heat transfer fluid temperatures in district heating are achieved through ultra-low temperature networks, referred to as 5th generation district heating networks (5GDHNs). Low temperatures in heat distribution results in an extremely different configuration of 5GDHN compared to traditional district heating network, especially in the grid substation due to the inability to directly couple the grid with the buildings. This paper presents a detailed design of a 5th generation substation prototype, which is carried out to verify the proper operation and monitor the performance of this type of substation in a real case study. The prototype is fed by low-temperature waste heat, currently dissipated through evaporative towers, and will be built in the city of Brescia, Italy. The layout of the substation prototype, consisting of a bidirectional pumping system, a reversible water-to-water heat pump, an inertial thermal energy storage and a heat exchanger, is presented. An analysis is performed to figure out which refrigerant offers the best performance of the heat pump. In addition, fixed the refrigerant, the performance of the grid connected heat pump is found to be increased from 29.5% to 55.5% for both heating and cooling compared with a stand-alone air-to-water heat pump solution. Finally, the process flow diagram and the piping and instrumentation diagram of the substation are presented and commented

Performance analysis of a large TES system connected to a district heating network in Northern Italy

The addition of storage capacity to district heating systems increases flexibility and expands the range of usable heat sources. Despite their apparently simple nature, thermal energy storage (TES) tanks display a wide range of performances due to different construction and operation choices, as proven by numerous literature studies. However, most of the investigations focus on domestic-size tanks of few cubic metres or, on the other hand, very large seasonal storages of hundreds of thousands of cubic metres. In this work, the performances of a 5000 m3 TES recently introduced in a district heating network in Brescia, Italy, are experimentally analysed using temperature and flow rate measurements acquired over two months in the heating season. First-law efficiencies, exergy, and stratification parameters are calculated and discussed. Energy and exergy efficiencies computed for all examined cycles are above 90%, in line with literature values for smaller and larger TESs. The thermocline profile is generally stable through the cycle unless anomalous events occur, and its average thickness is below 4% of the water height. The combined analysis of single-point indicators, thermocline profiles, and qualitative temperature heatmaps shows that short partial charge/discharge events followed by long stand-by periods negatively affect performances. Stratification efficiency and stratification number give further time-dependent information on the vertical distribution of temperatures in the TES. Heat losses towards the outside are also estimated and discussed in the light of integrative measurements performed on other TESs with similar characteristics, showing that particular care must be paid to the top, where dissipation could be increased by evaporation phenomena if the water surface is not protected

EMISSIONS REDUCTION FROM PELLET STOVESTHROUGH BURNER POT MODIFICATIONS

In this study, results of an extensive set of experiments onfive wood pellet stoves (8-11 kW nominal power) have been per-formed to verify whether carbon monoxide (CO), particulatematter (PM) and nitrogen monoxide (NO) emissions can be re-duced upon modification of burner pot geometry, depth and airinlet positions. A modification of “traditional” burner pot geom-etry brings CO emission close to zero. Also PM emissions arereduced but not as much as those of CO. It is verified that increas-ing the burner pot’s depth, PM emissions can be further reducedcompared to the less deep burner pot. Finally, since plots of in-stantaneous emissions versus O2content exhibit significant scat-tering and do not show a clear correlation, plots of mean valueof emissions, over narrow intervals of O2, versus O2are intro-duced. These plots show an optimal interval of O2content thatminimizes emissions

Perception of changes in marine benthic habitats: The relevance of taxonomic and ecological memory

Having a reliable ecological reference baseline is pivotal to understanding the current status of benthic assemblages. Ecological awareness of our perception of environmental changes could be better described based on historical data. Otherwise, we meet with the shifting baseline syndrome (SBS). Facing SBS harmful consequences on environmental and cultural heritage, as well as on conservation strategies, requires combining historical data with contemporary biomonitoring. In the present “era of biodiversity”, we advocate for (1) the crucial role of taxonomy as a study of life diversity and (2) the robust, informative value of museum collections as memories of past ecosystem conditions. This scenario requires taxonomist skills to understand community composition and diversity, as well as to determine ecosystem change trends and rates. In this paper, we focus on six Mediterranean benthic habitats to track biological and structural changes that have occurred in the last few decades. We highlight the perception of biological changes when historical records make possible effective comparisons between past reference situations and current data. We conclude that the better we know the past, the more we understand present (and will understand future) ecosystem functioning. Achieving this goal is intrinsically linked to investing in training new taxonomists who are able to assure intergeneration connectivity to transmit cultural and environmental heritage, a key aspect to understanding and managing our changing ecosystems

Plastic Optical Fiber Technology for Reliable Home Networking: Overview and Results of the EU Project POF-ALL

The rising performance of broadband connections for residential users, particularly in conjunction with fiber to the home, will present a new challenge for telecom operators in the short and medium terms: how to deliver the high bit rate digital signals with high quality-of-service to all consumer devices scattered inside the building of final users? Among the many different solutions for the home network, we review in this article the use of polymer optical fibers for short-reach and high-capacity optical communications for residential customer premises. POF is an easy-to-install, low-cost, and eye-safe solution for these networks, with the potential of being future-proof. In this article the state of the art in POF technology is presented by summarizing significant results achieved in the European project POF-ALL. Data transmission rates of more than 1 Gb/s over 50+ m and 100 Mb/s over 200+ m of standard step-index POF have been show

A biomass powered Ringbom-Stirling engine for developing countries: a low-budget solution for distributed electricity generation

n/

Effects of Bulk Viscosity in Non-linear Bubble Dynamics

The non-linear bubble dynamics equations in a compressible liquid have been modified considering the effects of compressibility of both the liquid and the gas at the bubble interface. A new bubble boundary equation has been derived, which includes a new term resulted from the liquid bulk viscosity effects. The influence of this term has been numerically investigated considering the effects of water vapor and chemical reactions on the bubble evolution. The results clearly indicate that the new term has an important damping role at the collapse, so that its consideration decreases the amplitude of the bubble rebounds after the collapse. This damping feature is more remarkable for higher deriving pressures.Comment: 4 pages, 7 figure

CHARACTERIZATION AND VALORIZATION OF MAIZE LANDRACES FROM VALLE D'AOSTA

During 1949-1950 in Italy begun a formal investigation to characterize maize (Zea mays L.) cultivation. In 1954, started a project for the sampling of all Italian maize landraces; this work ended with the collection of 562 different accessions collected in all regions with the exception of Valle d’Aosta, even if historical cultivation of maize in this Region is well documented. In Italy maize landraces have been extensively grown until the mid of the XX century when the cultivation of hybrid took place due to their significant agronomic performances. Despite that, being Valle d’Aosta a mountain region where intensive maize cultivation never started, it was possible to preserve the presence of some landraces. These local materials, which are still cultivated, mainly at domestic level, have high importance from a genetic and historical point of view. Recently, 5 maize landraces from Valle d’Aosta and 2 landraces from the adjacent Canavese (Piedmont) have been collected and subjected to historic, morphologic and genetic characterization. These landraces were named after the sampling location as it follows: Arnad, Arnad-Crest, Chatillon, Entrebin, Perloz, Bianco Canavese, and Rostrato Canavese. Firstly, on these 6 varieties the historic characterization has been carried out. Information and photographs have been searched in local archives and this was crucial to prove their long presence in all the sampling sites under study. From this historic reconstruction, the variety Entrebin resulted as the one that is better historically characterized. To study the variability and differentiation of landraces from Valle d’Aosta, the genetic characterization was performed by the means of 10 SSR markers tested on 20 samples from each landrace. This study highlighted a significant genetic variability among the landraces and, especially, a good level of differentiation between the accessions under investigation. This last result may be explained by the long reproductive isolation experienced by these materials. Complete morphological characterization is actually ongoing. Preliminary morphological observations revealed that these landraces have, generally, flint kernels with the exception of Bianco Canavese (dent) whose color is variable from white (Bianco Canavese) to dark red (Chatillon). Arnad landrace showed 8 kernel rows, probably being an Eight-rowed Flint while the others presented more rows, like many Derived Races. Interestingly, Perloz and Rostrato Canavese showed kernels with an apical beak which was more pronounced in the latter. This suggest that these two landraces belong to the “Rostrata” group, which is common in mountain areas. The present work confirms the importance of mountain areas in conserving biodiversity and increases the rich Italian maize germplasm with materials well adapted to marginal areas. Such new genetic variability may be used to breed new materials for a more resilient agriculture

Evaluation of the dual mTOR / PI3K inhibitors Gedatolisib (PF-05212384) and PF-04691502 against ovarian cancer xenograft models

We are grateful to Wyeth/Pfizer (ONC-EU-150) and to the Scottish Funding Council (SRDG HR07005) for support of this study.This study investigated the antitumour effects of two dual mTOR/PI3K inhibitors, gedatolisib (WYE-129587/PKI-587/PF-05212384) and PF-04691502 against a panel of six human patient derived ovarian cancer xenograft models. Both dual mTOR/PI3K inhibitors demonstrated antitumour activity against all xenografts tested. The compounds produced tumour stasis during the treatment period and upon cessation of treatment, tumours re-grew. In several models, there was an initial rapid reduction of tumour volume over the first week of treatment before tumour stasis. No toxicity was observed during treatment. Biomarker studies were conducted in two xenograft models; phospho-S6 (Ser235/236) expression (as a readout of mTOR activity) was reduced over the treatment period in the responding xenograft but expression increased to control (no treatment) levels on cessation of treatment. Phospho-AKT (Ser473) expression (as a readout of PI3K) was inhibited by both drugs but less markedly so than phospho-S6 expression. Initial tumour volume reduction on treatment and regrowth rate after treatment cessation was associated with phospho-S6/total S6 expression ratio. Both drugs produced apoptosis but minimally influenced markers of proliferation (Ki67, phospho-histone H3). These results indicate that mTOR/PI3K inhibition can produce broad spectrum tumour growth stasis in ovarian cancer xenograft models during continuous chronic treatment and this is associated with apoptosis.Publisher PDFPeer reviewe