Ocean thermal and power energy systems are promising driving forces for seashore coastal communities to achieve net-zero energy/emission target, whereas energy planning and management on ocean thermal/power and distributed building integrated photovoltaic (BIPV) systems are critical, in terms of serving scale sizing and planning on geographical locations of district building community, and cycling aging of battery storages. However, the current literature provides insufficient studies on this topic. This study aims to address this research gap by transforming towards zero-energy coastal communities from the district level in subtropical regions, including centralised seawater-based chiller systems, distributed BIPVs and coastal oscillating water column technologies, as well as multi-directional Vehicle-to-Building energy interaction paradigms. Advanced energy management strategies were explored to enhance renewable penetration, import cost-saving, and deceleration of battery cycling aging, in response to relative renewable-to-demand difference, off-peak grid information with low price, and real-time battery cycling aging. Furthermore, in accordance with the power generation characteristic of two wave stations (i.e., Kau Yi Chau (KYC) and West Lamma Channel (WLC)) in Hong Kong, energy system planning and structural configurations of the coastal community were proposed and comparatively studied for the multi-criteria performance improvement. Research results showed that, compared to an air-cooled chiller, the water-cooled chiller with a much higher Coefficient of Performance (COP) will reduce the energy consumption of cooling systems, leading to a decrease in total electric demand from 134 to 126.5 kWh/m²·a. The scale for the net-zero energy district community with distributed BIPVs and oscillating water column was identified as 5 high-rise office buildings, 5 high-rise hotel buildings, 150 private cars and 120 public shuttle buses. Furthermore, the geographical location planning scheme on the Case 1 (office buildings close to KYC, and hotel buildings close to WLC) was identified as the most economically and environmentally feasible scheme, whereas the Case 3 (only office buildings are planned close to all power supply with oscillating water column) showed the highest flexibility in grid electricity shifting, together with the highest value of equivalent battery relative capacity. This study demonstrates techno-economic performances and energy flexibility of frontier ocean energy technologies in a coastal community under advanced energy management strategies, together with technical guidance for serving scale sizing and planning on geographical locations. The research results highlight the prospects and promote frontier ocean energy techniques in subtropical coastal regions.

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Integrating phase change materials (PCMs) in buildings cannot only enhance the energy performance, but also improve the renewable utilization efficiency through considerable latent heat during charging/discharging cycles. However, system performances are dependent on PCMs’ integrated forms, heat transfer enhancement solutions, system operating modes, together with optimal geometrical and operating parameters. In this study, passive, active, and combined passive/active solutions in PCMs systems have been comprehensively reviewed, when being applied in heating, cooling and electrical systems, together with a dialectical analysis on advantages and disadvantages. In addition to novel system designs, interdisciplinary applications of machine learning have been reviewed and formulated, from perspectives of reliable structures, smart operational controls, and stochastic uncertainty-based performance prediction. Furthermore, a generic methodology with a systematic and hierarchical procedure has been proposed, with the implementation of machine-learning based technique for optimisations during both design and operation periods. The mechanisms of machine learning techniques were characterised as the simplifications of modelling and optimization processes, through the errors-driven update, the support vector regression and the backpropagation neural network. Several technical challenges were identified, such as the heat transfer enhancement, the novel structural configurations and the flexible switch on operating modes. Finally, identified challenges on machine learning include the development of advanced learning algorithms for efficient performance predictions, optimal structural configurations on neural networks, the trade-off between computational complexity and reliable optimal solutions, and so on. The formulated climate-adaptive designs, intelligent operations, uncertainty-based analysis and optimisations with interdisciplinary machine learning techniques can promote PCMs applications in sustainable buildings.@en