Abstract

The mutual conversion of heat energy and surface energy during the adsorption and desorption of working fluids on the surface of nano-porous materials can improve the heat storage capacity for energy storage. In this paper, the energy storage properties of two industrial fluids, HFO-1336mzz(Z) and Hexamethyldisiloxane(MM),with MOF-200 nanoparticle, were investigated by means of molecular dynamics simulations and grand canonical Monte Carlo simulations. It shows that the adsorption capacity of HFO-1336mzz(Z) in MOF is higher than that of MM. Moreover, the increment ratio of thermal energy storage properties of HFO-1336mzz(Z)/MOF-200 mixture is better than that of MM/MOF-5 mixture.

Abstract

Thermochemical heat storage has the advantages of high storage density and low heat loss, which has been an important component in energy system. A cylindrical reaction bed with heat transfer fluid as the heat source is established to study the dehydration process of Ca(OH)2. Some methods are proposed to improve heat storage performance. The effects of strengthening heat transfer, enhancing vapor flow, and simultaneously enhancing heat transfer and vapor flow on heat storage rate and density for the process are analyzed by adding metal foam and fluid channels. The results show that improving heat transfer and fluid flow at the same time is the most effective way to improve thermochemical heat storage performance. During the heat storage process, it shortens the reaction time by 45.8%, while
heat storage capacity is only reduced by 6.2%. In short, the effects of both heat transfer and vapor flow should be considered for the design of reaction beds of the thermochemical heat storage system.

Abstract

Energy storage systems are seen as key technologies in the decarbonisation of energy systems and are expected to ensure flexibility and security of supply in various applications. Depending on their operation within these applications, they contribute to changing the environmental impact of a specific energy system. In this study, energy storage is used to avoid wind energy curtailment. In order to show the effects on different energy systems, various comparable scenarios based on real energy systems were created. In the respective scenarios, a simulation was carried out without storage, then storage was added and its operation was optimised so that as much of the wind energy as possible was integrated. The ecological effect of this integration was analysed using the LCA method. The results show that in the scenarios where wind energy is curtailed, the use of storage has a positive environmental effect, because if the wind energy is integrated less fossil fuels are used.

Abstract

The operation of microgrids (MGs) has garnered much attention in recent years due to their potential for leveraging renewable and non-renewable energy sources in a well-integrated system. One MG configuration which has not been extensively studied is the islanded vehicle-borne MG (VBMG). Optimizing the operation of any MG is important to ensure power security, resilience, and cost. The main factor considered in this paper is an operational condition in which additional fuel supply cannot reach an islanded VBMG. This paper discusses the optimal operation a VBMG while maximizing the amount of time given finite fuel constraints. The result can be key to ensuring successful power supply for critical tasks in applications such as disaster rescue and recovery, mobile medical services, and military applications.

Abstract

Utility scale solar farms are being rapidly developed to reduce carbon footprint and to help meet ambitious energy goals set by state and federal governments. Using computational fluid dynamics (CFD), we are developing comprehensive design tools to investigate the microclimate of a solar farm. In this study, we define the term “ventilation” to qualitatively assess wind flow through a solar farm and measure its effect on solar module efficiency. We model a solar farm and compare the simulation results to a modified site design with improved ventilation. This investigation provides a basis for further studies on design and predictive models of solar farms, and it makes an argument for combining agriculture and photovoltaics through agrivoltaics.

Abstract

This paper introduces a new innovative concept for the PV rooftop design. It is intended to replace the conventional roof tile with a new arrangement using solar collector cartridges. The new cartridge design encapsulates a frameless PV panel and thermal insulation material in a “double E-Shape” section frame, to ease the assembly of the cartridge components. Two design modules solar collector cartridges were proposed to suit the installation arrangement on the roof. Where, in the first design the solar collector cartridges are placed on a pre-prepared rectangular section frame, such that every two adjacent cartridges provide a proper sealing, while the system wiring is arranged to pass through the hollow section frame. The other solar collector cartridge module design is provided with an interlock arrangement. Both modules design will act to limit the heat flow from the rooftop to the building interior space by 60% compared to the conventional roof tile. Rainwater runway channels were provided to ease water flow and cleaning. Air vents were made in the body of the solar collector cartridge to cool the PV panel. The cartridge design module dimension of 0.915 m (L) x 0.790 m (W) x 0.06 m (H). It occupies an area of 0.72 m2, and less than 15 kg to ease handling, installation, and maintenance. While capable to generate an average daily energy of 1.04 kWh/m2.

Abstract

Solar photovoltaic technology is a mature, stable and sustainable energy solution with important social and economic benefits. This study aims to investigate the technical and economic feasibility of installing solar PV systems on the building roofs in the university campus. The techno-economic analysis was carried out under three installation scenarios: PV modules parallel to the pitched roof, PV modules aligned at the optimal tilt angle on flat roof and pitched roof, respectively. The results show that, the flat roof has the potential installed capacity of 3.82 MW with an annual generation capacity of 4.51 GMh, while the pitched roof has the potential installed capacity of 2.45 MW and 2.64 MW with an annual generation capacity of 2.89 GWh and 3.11 GWh depending on two installation orientations and tilt angles, respectively. The economic analysis of the above three scenarios shows that all PV systems are in profit and positive net cash flow in year 5 for PV projects installed at optimal tilt on flat roofs and parallel to the roof on pitched roofs, and positive net cash flow in year 6 for PV projects installed at optimal tilt on pitched roofs.

Abstract

This study aims to assess the amount of land needed by the transition towards carbon neutrality of the European power system in 2050. We endogenized the land variable in eTIMES-EU, a long term planning model for the interconnected EU power system. We then assess the impact of explicit constraints on land use on the optimal trajectory and portfolio to meet carbon neutrality.

Abstract

The relationship between urban and building factors and building energy use is important for low-carbon city development. However, previous empirical studies often encountered the nonlinearity and non-normality issues common in complex urban datasets. This study examines the nonlinear influence of urban and building factors on building energy use under complex distribution conditions using the quantile regression model. This study focuses on Seoul’s residential building electricity use in August 2017 and compares the quantile regression model and the ordinary least squares (OLS) model. The quantile regression results are generally in line with OLS results. However, considering the energy use distributions, the quantile regression results show that nonlinear influences of the urban and building factors on building energy use are strong at the right tail of the energy use distribution. Specifically, the positive relationship between coverage ratio and building energy seems to change rapidly above quantile 80%. The influence of distance to water body on building energy is insignificant in 25% and 50% quantile models, but it turns to a significantly negative effect at quantile 75% and above. Unlike the OLS results, no significant difference between the older adults ratio is found in all quantile models. This study suggests that the quantile regression reveals the nonlinear relationship between urban and building factors and building energy use, providing more detailed evidence for policymaking.