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Demonstrating a smart controller in a hospital integrated energy system

Integrated energy systems have recently gained primary importance in clean energy transition. The combination of the electricity, heating and gas sectors can improve the overall system efficiency and integration of renewables by exploiting the synergies among the energy vectors. In particular, real-time optimization tools based on Model Predictive Control (MPC) can considerably improve the performance of systems with several conversion units and distribution networks by automatically coordinating all interacting technologies. Despite the relevance of several simulation studies on the topic, however, it is significantly harder to have an experimental demonstration of this improvement. This work presents a methodology for the real-world implementation of a novel smart control strategy for integrated energy systems, based on two coordinated MPC levels, which optimize the operation of all conversion units and all energy vectors in the short- and long-term, respectively, to account also for economic incentives on critical units. The strategy that was previously developed and evaluated in a simulation environment has now been implemented, as a supervisory controller, in the integrated energy system of a hospital in Italy. The optimal control logic is easily actuated by dynamically communicating the optimal set-points to the existing Building Management System, without having to alter the system configuration. Field data collected over a two-year period, firstly when it was business as usual and when the new operation was introduced, show that the MPC increased the economic margin and revenues from yearly incentives and lowered the amount of electricity purchased, reducing dependency on the power grid.

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Integrated Exposure and Algal Ecotoxicological Assessments of Effluents from Secondary and Advanced-Tertiary Wastewater-Treatment Plants.

The great concern over the environmental impact of wastewaters has led to the designing of advanced treatment processes to upgrade conventional treatment plants and achieve a significant reduction of contaminants in receiving waters. In the present study we combined chemical and ecotoxicological analyses, aiming to evaluate the reduction of toxicity effects associated with the removal of micropollutants and to define the contribution of the detected compounds to the overall toxicity of the mixtures in a series of wastewater effluents collected from a secondary treatment (OUT 2) and from a tertiary activated carbon treatment (OUT 3) plant. The target compounds were selected after a screening procedure among pharmaceuticals, musk fragrances, and trace metals. The classical algal growth inhibition test was conducted on the original effluent samples and on different fractions obtained by solid-phase extraction (SPE) treatment. A good accordance was found between the removal of toxicity (30%-80%) and organic compounds (70%-80%) after the tertiary treatment, suggesting its high efficiency to improve the wastewater quality. The discrepancy between the contribution to the overall toxicity of the nonadsorbable compounds (i.e., inorganic or very polar organic compounds) as experimentally measured by the SPE bioassays (18%-76%) and calculated by the concentration addition approach (>97%) could be mitigated by including the bioavailability correction in metal-toxicity modeling of wastewater mixtures. For the organic compounds, the toxic equivalency method enabled us to quantify the portion of toxicity explained by the detected chemicals in both OUT 2 (82%-104%) and OUT 3 (5%-57%), validating the selection of the target molecules. The applied integrating approach could be implemented by the inclusion of both additional target chemicals and toxicity endpoints. Environ Toxicol Chem 2022;41:2404-2419. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

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Setup and testing of smart controllers for small-scale district heating networks: An integrated framework

Nowadays, the growing availability of renewable energy resources is an opportunity to reduce carbon emissions but also a challenge, as advanced control technologies are required. The new generation of smart district heating and cooling networks, for instance, pledges efficient energy distribution, flexibility and low-carbon energy integration. However, in the literature it is hard to find comprehensive frameworks for the integrated setup and testing of smart control strategies. This paper defines and demonstrates a framework that involves all steps of the controller development for small-scale district heating networks: from conceptualization to prototype testing. The innovative controller prototype, which relies on Model Predictive Control and aims to minimize operating costs and/or energy, is demonstrated in three original case studies, one in a simulation environment and two in real systems of different complexity in operational conditions. Compared to the control approaches previously adopted, based on predefined rules and operator experience, the smart solution achieves 6% reduction in cost and up to 34% reduction in energy consumption while meeting user requirements. The fast replicability of the proposed integrated methodology can foster the transition toward the next generation of smart heating networks.

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Improving and upgrading an existing activated sludge with a compact MBBR – disc filters parallel line for municipal wastewater treatment in touristic alpine areas

Abstract Many wastewater treatment plants (WWTP) in touristic areas struggle to achieve the effluent requirements due to seasonal variations in population. In alpine areas, the climate also determines a low wastewater temperature, which implies long sludge retention time (SRT) needed for the growth of nitrifying biomass in conventional activated sludge (CAS). Moreover, combined sewers generate high flow and dilution. The present study shows how the treatment efficiency of an existing CAS plant with tertiary treatment can be upgraded by adding a compact line in parallel, consisting of a Moving Bed Biofilm Reactor (MBBR)-coagulation-flocculation-disc filtration. This allows the treatment of influent variations in the MBBR and a constant flow supply to the activated sludge. The performance of the new 2-step process was comparable to that of the improved existing one. Regardless significant variations in flow (10,000–25,000 m3/d) and total suspended solids (TSS) (50–300 mg/L after primary treatment) the effluent quality fulfilled the discharge requirements. Based on yearly average effluent data, TSS were 11 mg/L, chemical oxygen demand (COD) 27 mg/L and total phosphorus (TP) 0.8 mg/L. After the upgrade, ammonium nitrogen (NH4-N) dropped from 4.9 mg/L to 1.3 mg/L and the chemical consumption for phosphorus removal was reduced.

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Development and application of a Predictive Controller to a mini district heating network fed by a biomass boiler

Energy saving is actually recognized as one of the most significant ways to reduce primary energy consumption and pollutant emissions. Due to the remarkable importance of heating systems and heat distribution grids, Siram by Veolia and the University of Parma have developed an optimal control system for District Heating Networks. Usually building control systems are designed to manage plants relying on past experience: the optimal control system described in the paper defines plant management strategy on the basis of the future behavior of the systems and the external environment. The proposed control system has been applied to the heating system and the distribution network of a school complex in Podenzano (Emilia-Romagna region). The district heating supplies heat to three different buildings (primary school, secondary school and sports hall). The heating plant is composed of three generators (two fed by natural gas and one by wooden biomass), a Thermal Energy Storage, two main distribution manifolds (supply and return) and three secondary circuits, which distribute heat to the buildings. In the first part of the paper the control algorithm is described, split into plant simulation models and the optimization algorithm. In the second part, the real application and the new communication architecture applied on site are outlined and, finally, the obtained results are reported highlighting the management strategies of generators and pumps. The optimal control strategy application gave important results in terms of energy saving, in particular the energy supplied to the buildings dropped significantly, this is the result of knowing the building behavior in advance.

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Water supply and sustainability: life cycle assessment of water collection, treatment and distribution service

The aim of the present paper is to describe the development of a life cycle assessment study of the service of potable water supply in Sicily, Italy. The analysis considers the stages of collection, treatment and distribution of potable water through the regional network, whilst the use stage of water is not included. The selection of a methodological pattern coherently with the requirements of an environmental label, such as the EPDs, aims at allowing comparability among different studies. The analysis shows the shares of impacts along the life cycle chain, i.e. outputs by well fields and spring groups, purification and desalination plants, water losses in the waterworks, electrical consumption of waterworks systems and impacts of network maintenance. With regard to global warming potential (GWP), the impact of purification plants represents a 6–7 % share of the total, whilst desalination is at 74 %. Water losses in the waterworks show an impact of 15–17 %; the contribution owing to electrical consumption of waterworks systems and network maintenance results to be 3 %. Desalination plants represent the major contribution to all impact categories considered. In respect to management issues, the most relevant impact categories resulted to be GWP, non-renewable energy resources and water consumption. Since the results for non-renewable energy resources are strictly connected to GWP emissions, carbon footprint and water footprint can be profitably used as single-issue indicators without the risk of burden shifting in studies aiming to evaluate the impact of potable water distribution.

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Limitation des pertes en eau des réseaux

Chaque annee en France, 34 milliards de m 3 sont preleves en moyenne : production d'energie (57%), eau potable (18%), industries (10%), agriculture (15%), dont plus de 80% sont restitues au milieu naturel. Le rechauffement climatique actuel conduit a de fortes disparites geographiques et saisonnieres. Et a certaines periodes des annees les plus seches, jusqu'a 60 departements ont connu des restrictions de consommations plus ou moins fortes. Dans le cas de l'eau potable, il est demande un effort particulier aux responsables de la production et de la distribution afin de limiter les pertes sur reseau estimees a 1 millard de m 3 , dont 50% environ seraient techniquement recuperables, mais a des cout pouvant etre tres eleves. C'est la double demarche d'une approche economique progressivement amendee par celle de developpement durable qui est recherchee ici. Un groupe de travail Astee propose donc une demarche economico-environnementale integrant : ― une meilleure connaissance du patrimoinde de distribution, de son fonctionnement avec representation sur SIG, ― la mise en place d'outils de surveillance des pertes sur reseau, de bases de donnees et d'aide a la decision, ― un suivi grâce a des indicateurs de performance, ― puis, une etude financiere et environnementale. Celle-ci sera etablie pour permettre d'apprecier les enjeux reels dans le contexte particulier concerne (caracterisitiques et etat du reseau, investissement dans une nouvelle ressource, augmentation de la production ou renforcement du reseau, mise en place d'une interconnexion, impact sur les differentes parties prenantes des ressources en eau...) Ce n'est qu'ensuite que pourra etre adopte un plan d'action avec court et moyen terme, etaye des engagements des differentes parties et des indicateurs de suivis adequats.

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