142 research outputs found

    Team UOW solar decathlon house: refurbishment demonstration

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    This paper describes a practical demonstration of how to refurbish a typical Australian timber framed fibro house to become a net-zero energy, Solar Decathlon (SD) home. The Team UOW Illawarra Flame House was entered in the SD China 2013 competition and was eventually the overall winner of the competition. The house refurbishment method was illustrated initially through architectural changes to the design of the nominal original house in order to improve functionality, daylighting and natural ventilation. Energy simulations for the original house and the house with the architectural refurbishment were then carried out to determine the thermal envelope retrofit targets and investigate the thermal performance enhancement of the house due to its envelope upgrade. An innovative air-conditioning system, which included solar photovoltaicthermal collectors and a phase change material thermal storage unit, was developed and employed to maintain indoor thermal comfort conditions. The results from both experiments and simulations showed that the thermal and energy performance of the house was significantly improved through the effective implementation of the suite of retrofits. The house demonstrated the potential for existing Australian housing stock to achieve net-zero energy consumption while meeting high indoor thermal comfort standards

    Control-oriented modelling and operational optimization of a borehole thermal energy storage

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    Seasonal thermal energy storage is an effective measure to enable a low carbon future through the integration of renewables into the energy system. Borehole thermal energy storage (BTES) provides a solution for long-term thermal energy storage and its operational optimization is crucial for fully exploiting its potential. This paper presents a novel linearized control-oriented model of a BTES, describing the storage temperature dynamics under varying operating conditions, such as inlet temperature, mass-flow rate and borehole connection layouts (e.g. in-series, in-parallel or mixed). It supports an optimization framework, which was employed to determine the best operating conditions for a heat pump-driven BTES, subject to different  intensity profiles of the electricity. It was demonstrated that this boundary condition, due to its seasonal variation, is critical for the optimal operation of the system, as increasing heat pump efficiency in winter while accepting a lower one in summer can be beneficial. Results for an exemplary district case, subject to two different  intensity profiles, show that a lower relative intensity in summer compared to the one in winter leads to a higher optimal operating temperature of the storage. The district system studied is heating-dominated, effectively enabling the BTES to cover only 20% of the total heat demand, leading to limited total yearly CO2 emissions savings of 2.2% to 4.3%. When calculating the benefits associated with the heating and cooling demand handled by the BTES, a higher  emission reduction in the range of 12.8%–19.9% was found. This highlights the BTES potential when subject to more balanced loads.

    Hybrid model predictive control of a residential HVAC system with PVT energy generation and PCM thermal storage

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    This paper describes an experimental investigation into the performance of a Hybrid Model Predictive Control (HMPC) system implemented to control a novel solar-assisted HVAC system servicing the Team UOW Solar Decathlon house, the overall winner of the Solar Decathlon China 2013 competition. This HVAC system consists of an air-based photovoltaic thermal (PVT) collector and a phase change material (PCM) thermal store integrated with a conventional ducted reverse-cycle heat pump system. The system was designed for operation during both winter and summer, using daytime solar radiation and night sky radiative cooling to increase the energy efficiency of the air-conditioning system. The PVT collector can exchange heat with the PCM thermal storage unit, and the stored heat can be used to condition the space or precondition the air entering the air handling unit (AHU). The HMPC controller includes two levels of control, where the high-level controller has a 24-hour prediction horizon and a 1-hour control step is used to select the operating mode of the HVAC system. Low-level controllers for each HVAC operational mode have a 1-hour prediction horizon and a 5-minute control step, and are used to track the trajectory defined by the high-level controller and to optimize the operating mode selected. The results from this preliminary experimental work have demonstrated the value of the HMPC approach in optimally controlling the solar-assisted HVAC system in the Solar Decathlon house. Results show that the HMPC controller successfully selected the appropriate operating mode to achieve multiple objectives, including: maintenance of indoor comfort conditions within a defined, and potentially variable, thermal comfort band; and optimization of the overall energy efficiency of the system using all available on-site energy resources

    Hybrid model predictive control of a residential HVAC system with PVT energy generation and PCM thermal storage

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    This paper describes an experimental investigation into the performance of a Hybrid Model Predictive Control (HMPC) system implemented to control a novel solar-assisted HVAC system servicing the Team UOW Solar Decathlon house, the overall winner of the Solar Decathlon China 2013 competition. This HVAC system consists of an air-based photovoltaic thermal (PVT) collector and a phase change material (PCM) thermal store integrated with a conventional ducted reverse-cycle heat pump system. The system was designed for operation during both winter and summer, using daytime solar radiation and night sky radiative cooling to increase the energy efficiency of the air-conditioning system. The PVT collector can exchange heat with the PCM thermal storage unit, and the stored heat can be used to condition the space or precondition the air entering the air handling unit (AHU). The HMPC controller includes two levels of control, where the high-level controller has a 24-hour prediction horizon and a 1-hour control step is used to select the operating mode of the HVAC system. Low-level controllers for each HVAC operational mode have a 1-hour prediction horizon and a 5-minute control step, and are used to track the trajectory defined by the high-level controller and to optimize the operating mode selected. The results from this preliminary experimental work have demonstrated the value of the HMPC approach in optimally controlling the solar-assisted HVAC system in the Solar Decathlon house. Results show that the HMPC controller successfully selected the appropriate operating mode to achieve multiple objectives, including: maintenance of indoor comfort conditions within a defined, and potentially variable, thermal comfort band; and optimization of the overall energy efficiency of the system using all available on-site energy resources

    Model Predictive Control (MPC) for Enhancing Building and HVAC System Energy Efficiency: Problem Formulation, Applications and Opportunities

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    In the last few years, the application of Model Predictive Control (MPC) for energy management in buildings has received significant attention from the research community. MPC is becoming more and more viable because of the increase in computational power of building automation systems and the availability of a significant amount of monitored building data. MPC has found successful implementation in building thermal regulation, fully exploiting the potential of building thermal mass. Moreover, MPC has been positively applied to active energy storage systems, as well as to the optimal management of on-site renewable energy sources. MPC also opens up several opportunities for enhancing energy efficiency in the operation of Heating Ventilation and Air Conditioning (HVAC) systems because of its ability to consider constraints, prediction of disturbances and multiple conflicting objectives, such as indoor thermal comfort and building energy demand. Despite the application of MPC algorithms in building control has been thoroughly investigated in various works, a unified framework that fully describes and formulates the implementation is still lacking. Firstly, this work introduces a common dictionary and taxonomy that gives a common ground to all the engineering disciplines involved in building design and control. Secondly the main scope of this paper is to define the MPC formulation framework and critically discuss the outcomes of different existing MPC algorithms for building and HVAC system management. The potential benefits of the application of MPC in improving energy efficiency in buildings were highlighted

    Design and optimal integration of seasonal borehole thermal energy storage in district heating and cooling networks

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    Conference Proceedings available at: https://proceedings.open.tudelft.nl/index.php/clima2022Technologies that can close the seasonal gap between summer renewable generation and winter heating demand are crucial in reducing CO2 emissions of energy systems. Borehole thermal energy storage (BTES) systems offer an attractive solution, and their correct sizing is important for their techno-economic success. Most of the BTES design studies either employ detailed modelling and simulation techniques, which are not suitable for numerical optimization, or use significantly simplified models that do not consider the effects of operational variables. This paper proposes a BTES modelling approach and a mixed-integer bilinear programming formulation that can consider the influence of the seasonal BTES temperature swing on its capacity, thermal losses, maximum heat transfer rate and on the efficiency of connected heat pumps or chillers. This enables an accurate assessment of its integration performance in different district heating and cooling networks operated at different temperatures and with different operating modes (e.g. direct discharge of the BTES or via a heat pump). Considering a case study utilizing air sourced heat pumps under seasonally varying CO2 intensity of the electricity, the optimal design and operation of an energy system integrating a BTES and solar thermal collectors were studied. The optimization, aiming at minimizing the annual cost and CO2 emissions of the energy system, was applied to two heating network temperatures and five representative carbon prices. Results show that the optimal BTES design changed in terms of both size and operational conditions, and reductions in emissions up to 43% could be achieved compared to a standard air-source heat pumps based system

    Parasuicide and drug self-poisoning: analysis of the epidemiological and clinical variables of the patients admitted to the Poisoning Treatment Centre (CAV), Niguarda General Hospital, Milan

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    Epidemiological knowledge of parasuicides and drug self-poisoning is still limited by a lack of data. A number of preliminary studies, which require further analysis, evidenced that parasuicidal acts occur more often among females, that the peak rate is generally recorded between the ages of 15 and 34 years and psychotropic medications seems to be the most frequently used. The aim of this study was to describe the demographic and clinical variables of a sample of subjects admitted to the Posisoning Treatment Centre (CAV), Niguarda General Hospital, Milan, following drug self-poisoning. Furthermore, this study is aimed to identify the risk factors associated to parasuicidal gestures, with special care for the used drugs, the presence of psychiatric or organic disorders, alcoholism and drug addiction. The study included the 201 patients attending the CAV in 1999 and 2000 who satisfied the criteria of self-poisoning attempts: 106 cases in 1999 and 95 in 2000. The sample had a prevalence of females (64%). The peak rates of parasuicides from drug self-poisoning were reached between 21 and 30 years among the females, and 31 and 40 years among the males. 81.6% of the patients used one or more psychoactive drugs, the most frequent being the benzodiazepines (58.7%), classic neuroleptics (16.9%) and new-generation antidepressants (SSRIs, SNRIs, NARIs) (12.9%). The prevalence of mood disorders was higher among females (64% vs 42%), whereas schizophrenia was more frequently diagnosed in males (22% vs 10%). 61% (33%) had a history of previous attempted suicides. The presence of clinically relevant organic diseases was observed in 24.9% of the sample

    Establishment and characterization of induced pluripotent stem cell (iPSCs) line UNIBSi014-A from a healthy female donor.

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    Abstract Peripheral blood mononuclear cells (PBMCs) derived from a healthy 40-year-old female were successfully transformed into induced pluripotent stem cells (iPSCs) by using the integration-free CytoTune-iPS Sendai Reprogramming method. The resulting iPSCs line exhibits a normal karyotype, expresses stemness markers and displays the differentiation capacity into the three germ layers. This human iPSCs line can be used as healthy control in disease modelling studies

    Think globally, act locally: Phylodynamic reconstruction of infectious bronchitis virus (IBV) QX genotype (GI-19 lineage) reveals different population dynamics and spreading patterns when evaluated on different epidemiological scales

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    nfectious bronchitis virus (IBV) represents one of the poultry industry major threats, particu- larly in high density producing countries. The emergence and spread of new IBV genotypes have frustrated the various disease control efforts implemented over time. Despite that, few comprehensive and large scale studies have been performed to understand the interna- tional and local spreading dynamics of this virus. In the present work, these phenomena were evaluated by implementing a Bayesian phylodynamic approach to reconstruct the epi- demiological patterns and population history of the QX genotype (currently renamed GI-19 lineage), the most relevant IBV lineage of the Old-World. Our analysis, based on 807 partial S1 sequences of strains collected from 18 countries between 1993 and 2015, demonstrates that this genotype originated in China well before its first identification. After a prolonged local circulation, it started spreading to other European, Asian and Middle East countries in successive waves, which were mirrored by concomitant fluctuations in viral population size. Interestingly, the within-Europe spread was characterized by a higher estimated migration rate compared with the inter-continental one, potentially reflecting the closer geographic and economic relationships among these countries. Nevertheless, the colonization of new states by the GI-19 lineage appeared to occur mostly by single introduction events in both intra and inter-continental spread, likely because of epidemiological factor and health policy combination which seems to prevent the frequent introduction and mixing of different strains. On the other hand, the within Italy QX circulation reconstruction showed a much more intricate connection network among different locations, evidencing the difficulty in con- trolling IBV spread especially in highly densely poultry populated areas. The presence of several well supported epidemiological links among distantly related Italian regions testifies that animal transportation and indirect transmission routes rather than local airborne diffu- sion contribute to the QX success and persistence at local scale. Globally, the spreading dynamics and evolution of the QX genotype were reconstructed from its very origin to nowa- days, demonstrating the need of more effective direct control measures, particularly within each country. Unfortunately, the incompleteness of available molecular epidemiology data represents an insurmountable limit which leaves many questions currently unsolved, thus highlighting the compulsoriness of a structured monitoring and data sharing system implementation

    Lack of evidence of Chikungunya virus infection among blood donors during the Chikungunya outbreak in Lazio Region, Italy, 2017

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    Background: The latest European Chikungunya virus (CHIKV) outbreak occurred in Italy in 2017, in the municipalities of Anzio and Rome (Lazio Region), with a secondary outbreak in the Calabrian Region. Most CHIKV infections are symptomatic but about 15% of people who acquire the infection may be asymptomatic. A retrospective study was conducted with the aim of assessing the prevalence of recent/ongoing CHIKV infections on the blood donor population in the Lazio Region, during the 2017 outbreak (including in the period before it was detected). Methods: The study was conducted on 4595 plasma samples from donors who donated in 14 different Blood Establishments in the Lazio Region, in the period June-November 2017. A total of 389 of these samples were collected in provinces not affected by the outbreak and were used as negative controls. All samples were tested for IgM detection by the use of an ELISA test, and positive samples were tested for confirmation through the use of a PRNT. Molecular tests were performed on sera that were found to be IgM-positive or borderline. Results: A total of 41 (0.89%) blood donors tested positive for IgM. None of these positive IgM ELISA results was confirmed either by PRNT or by molecular tests. Conclusions: Our study has shown no evidence of recent/ongoing CHIKV infection in blood donors of the affected area
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