Browsing by Author "Zhang, Yi"
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Item Metadata only An "ageing"' operator and its use in the highly constrained topological optimization of HVAC system design(2005-06-25) Zhang, Yi; Wright, Jonathan AndrewItem Metadata only ANN application to modelling and control of small absorption chillers(2012) Labus, Jerko; Korolija, Ivan; Marjanovic-Halburd, Ljiljana; Zhang, Yi; Coronas, AlbertoThe main aim of this paper is to demonstrate the application of Artificial Neural Networks (ANN) in small absorption chillers modelling and their control optimisation. The Genetic Algorithms (GA) optimisation method was coupled to the ANN model in order to solve the optimal operation problem where the objective function was the minimal primary energy consumption. This paper analyses the impact of control strategy on energy performance of small capacity absorption chillers, while emphasizing the usability of ANN model, and comparing this strategy to conventional operation strategies.Item Metadata only Comparison of conventional, parametric and evolutionary optimisation approaches for the architectural design of nearly zero energy buildings(2013) Naboni, Emanuele; Maccarini, Alessandro; Korolija, Ivan; Zhang, YiItem Metadata only A comparison of the ASHRAE secondary HVAC toolkit detailed and simple cooling coil models with manufacturers data.(2008) Korolija, Ivan; Hanby, V. I. (Victor Ian), 1942-; Marjanovic-Halburd, Ljiljana; Zhang, YiItem Metadata only Energy aspects of HVAC system configurations - problem definition and test cases(International Journal of Heating, Ventilation, Air-conditioning and Refrigeration Research, 2006-09-01) Zhang, Yi; Hanby, V. I. (Victor Ian), 1942-; Wright, Jonathan AndrewItem Metadata only Evolutionary synthesis of HVAC system configurations: algorithm development (RP1049).(2008) Wright, Jonathan Andrew; Zhang, Yi; Angelov, P.; Buswell, R. A.; Hanby, V. I. (Victor Ian), 1942-Item Metadata only Evolutionary synthesis of HVAC system configurations: experimental results(2008) Wright, Jonathan Andrew; Zhang, YiItem Metadata only How to integrate optimization into building design practice: lessons learnt from a design optimization competition(2013) Zhang, Yi; Tindale, Andy; Garcia, A. O.; Korolija, Ivan; Tresidder, E. G.; Gale, P.Item Metadata only Human environmental heat transfer simulation with CFD - the advances and challenges.(2009) Zhang, Yi; Novieto, Divine Tuinese; Ji, Y.Item Open Access HVAC system configurations: an energy aspect(HVAC&R Research, 2006) Zhang, Yi; Wright, Jonathan Andrew; Hanby, V. I. (Victor Ian), 1942-This paper studies the energy implications of HVAC system configuration by analysing energy balance and psychrometrics of typical and innovative systems. Three criteria have been established: (1) the ability to minimize outside air load; (2) the ability to eliminate simultaneous cooling and heating, and use mixing effectively; and (3) the availability of inter-zonal airflow. Configurations that meet these criteria would be able to deliver the desired indoor air quality with reduced energy consumption. The performance of nine 2-zone system configurations, including single-duct, dual-duct, fan-coil-based variations, and other specialize systems in the literatures, have been analysed for a number of operational conditions. The results confirmed that fan-coil-based configurations with inter-zonal airflow paths perform better than other configurations. The conclusion of this study may be used as a guideline to multi-zone system designs.Item Metadata only HVAC systems energy demand vs. building energy demand(2010-05-21) Korolija, Ivan; Hanby, V. I. (Victor Ian), 1942-; Zhang, Yi; Marjanovic-Halburd, LjiljanaBuilding energy demand is the amount of heating and cooling energy required to deliver the desired indoor conditions. It is dependent on various building parameters such as building fabrics, glazing percentage, occupancy pattern, level of internal gains, etc. Despite that building demand is often used for energy performance evaluation in the practice, it can be inaccurate and even misleading when the building is serviced by an HVAC system. The amount of energy required by the HVAC system from the primary sources or systems, to deliver the required heating and cooling in the building, does not equate building demand in most circumstances. An HVAC system may show different energy performance in different buildings, due to that the HVAC system’s characteristics and operational conditions are affected by the thermal load and behaviour of the building. It is therefore necessary to analyse the correlation between building’s dynamic load profile and the performance of the HVAC systems. In this paper, we used a typical rectangular UK office building with combined open plan and cellular offices to analyse the correlation between the building’s heating and cooling load profile and the performance of different HVAC systems, i.e. the variable air volume system (VAV), the constant air volume system (CAV), the fan coil with dedicated outside air system (FC) and the chilled ceiling with radiator heating and dedicated outside air system (ChCeil). Building fabrics are selected to comply with the latest UK national standards. By running a series of simulations in EnergyPlus and in-depth analysis of outputs, we aim to provide a set of guidelines on HVAC system selection at early design stages based on total energy performance.Item Metadata only Impact of model simplification on energy and comfort analysis for dwellings(2013) Korolija, Ivan; Zhang, YiItem Metadata only Influence of building parameters and HVAC systems coupling on building energy performance.(Elsevier, 2011) Korolija, Ivan; Marjanovic-Halburd, Ljiljana; Zhang, Yi; Hanby, V. I. (Victor Ian), 1942-Item Metadata only The minimum capacity of HVAC secondary systems (with capacity reduction by inter-zonal air-flow).(2008) Wright, Jonathan Andrew; Zhang, YiItem Open Access Model-based control of renewable energy systems in buildings(American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc., 2006) Zhang, Yi; Hanby, V. I. (Victor Ian), 1942-The paper describes a research project concerned with the problem of supervisory control of systems which combine a range of heat sources with active and passive thermal storage. The work is based around a prototype building which includes a ventilated PV array, solar air and water heating, biomass-fired boiler and a stratified thermal store. The supervisory control problem is, for each source, whether to deploy the received energy directly into the building, store for later use or to reject to the environment. These decisions are currently made by a building management system programmed with a complex, arbitrary set of rules and setpoints. The considerable number of operational states means that such a control system is very difficult to commission. Analysis of the data for the early stages of building operation indicate strongly that it is unlikely that optimal use is being made of the renewable energy sources with this approach. The objective of the research is to investigate the potential effectiveness of replacing the rule-based control scheme with one based on a combination of building/system model with an optimization algorithm. The existing building, plant and control systems were modeled using a commercial simulation environment and calibrated against measured data from the building. A period of swing-season operation was used to compare the existing control with that based on an optimal approach. Results indicate that significant improvements in system operation are possible, but also that significant improvement in execution time will be needed for any future on-line deployment.Item Metadata only A new application of high-efficient silver salts-based photocatalyst under natural indoor weak light for wastewater cleaning(Elsevier, 2015-06-14) Teng, Fei; Zhao, Yunxuan; Xu, Juan; Xu, Chuangye; Yang, Yang; Zhang, Qiqi; Paul, Shashi; Zhang, Yi; Chen, Mingdong; Zhao, Xudong; Hua, XiaAs a high-quantum-efficiency photocatalyst, the serious photo-corrosion of silver phosphate (Ag3PO4), limits the practical applications in water purification and challenges us. Herein, Ag3PO4 is found to have a high stability under natural indoor weak light irradiation, suggesting that we can employ it by adopting a new application strategy. In our studies, rhodamine B (RhB, cationic dye), methyl orange (MO, anionic dye) and RhB–MO mixture aqueous solutions are used as the probing reaction for the degradation of organic wastewater. It is found that RhB, MO and RhB–MO can be completely degraded after 28 h under natural indoor weak light irradiation, indicating that multi-component organic contaminants can be efficiently degraded by Ag3PO4 under natural indoor weak light irradiation. The density of natural indoor weak light is measured to be 72cd, which is merely one-thousandth of 300 W xenon lamp (68.2 × 103cd). Most importantly, Ag3PO4 shows a high stability under natural indoor weak light irradiation, demonstrated by the formation of fairly rare Ag. Furthermore, we also investigate the influence of inorganic ions on organic dyes degradation. It shows that the Cl− and Cr6+ ions with high concentrations in wastewater have significantly decreased the degradation rate. From the viewpoint of energy saving and stability, this study shows us that we can utilize the Ag-containing photocatalysts under natural indoor weak light, which could be extended to indoor air cleaning process.Item Metadata only Optimization of dwelling design under current and future climates using evolutionary algorithms in EnergyPlus(2013) Wright, A. J.; Korolija, Ivan; Zhang, YiDesigners of low energy dwellings face many challenges in making best use of space, and providing day lit and pleasant spaces, while minimising heat loss and overall carbon emissions to meet various environmental and legislative targets. These also have to be achieved within financial, spatial and planning constraints. In other words, the design exercise is a multi-criteria optimization exercise. Usually this is done using experience through iterative design development, assisted by various software tools ranging from relatively simple models such as the Standard Assessment Procedure (SAP), to detailed thermal simulation. This paper describes the use of parametric simulations using EnergyPlus on a computer cluster to arrive at optimal solutions, for both current and future climates. The tool is applied to some modern house designs proposed for developments in the UK.Item Metadata only Item Metadata only Performing complex parametric simulations with jEPlus(2010) Zhang, Yi; Korolija, IvanParametric study is a useful method for exploring alternative design options and establishing dependencies between design variables. The development of an open-source research tool, jEPlus, has been reported in 2009. The tool is designed to assist setting up parametric runs with EnergyPlus models, and to perform the simulations in “parallel” mode. This paper uses an example to demonstrate how jEPlus can be used for setting up complex parametric runs. In the example, four different building types and five HVAC system configurations were considered along with design parameters including insulation, glazing, temperature set points and day lighting control options. Further more, the simulations were carried out in three different climatic regions. Given that the total number of simulations exceeds 30,000, it would have been a tedious, if not impossible, job to set them up manually. jEPlus made it trivial, however, by automating the tasks such as generating input files for EnergyPlus, executing simulations, and extracting results.Item Metadata only Porous Ag 3 PO 4 microtubes with improved photocatalytic properties(Elsevier, 2014-04-17) Hua, Xia; Jin, Yujian; Wang, Kai; Li, Na; Liu, Haiqiu; Chen, Mingdong; Paul, Shashi; Zhang, Yi; Zhao, Xudong; Ten, FeiThe Ag3PO4 porous microtubes are, for the first time, prepared by a one-pot synthesis using polyethylene glycol 200 (PEG 200) as the reaction medium. This study establishes that PEG 200 plays a vital role in the formation of the unique structures. Under visible light irradiation (≥ 420 nm), the porous sample exhibits a higher photocatalytic activity for the degradation of RhB than solid Ag3PO4 and Ag3PO4 tetrapods, which has been mainly ascribed to the novel hollow structure.