Abstract

This article presents a two-dimensional axis-symmetric computational fluid dynamics (CFD) simulation of a three-stage travelling wave thermoacoustic engine using Ansys Fluent. The model incorporates porous media submodels to represent heat exchangers and regenerators, operating at a heating temperature of 600 K and an ambient temperature of 293 K, with helium as the working fluid stabilised around 3 MPa mean pressure. In comparison to traditional network models, CFD yields accurate results in solving the flow field and captures higher-order details in the fluid domain.

Abstract

The orientation of solar collector arrays significantly influences the efficiency and performance of solar thermal systems. However, in some instances, practical limitations may prevent the optimal orientation of these collector arrays. This research investigates the performance of a field of High Vacuum Flat Collectors (HVFPCs) under suboptimal conditions. Our test facility features 25 arrays located on both sides of a building’s roof. Each array forms a 6° angle with the horizontal plane. Of these, four panels are on the east-facing surface, and three are on the west-facing surface. All collectors within the arrays have a tilt angle of 15° and an azimuth angle of 0°. We began performance assessments using a single pyranometer placed between the two roof sides to gauge solar irradiation. Later, we used two pyranometers one on each roof side. Both had identical tilt and azimuth as the collectors, ensuring independent irradiation measurements. When comparing these measurements to numerical results from a dynamic simulation, we discovered that a comprehensive plant performance evaluation must account for the varied orientations of collectors in the arrays. These results underscore the need to consider collector orientation’s impact on performance, even if ideal orientations are unattainable due to installation challenges. Understanding how non ideal collector array orientation affects system efficiency leads to improved flow rate regulation techniques, optimizing performance and energy use.

Abstract

Hydrogen has gained significant attention as a possibly important energy vector in the pursuit of climate change mitigation objectives. Global demand for renewable hydrogen is anticipated to increase across many decarbonization scenarios. To meet this demand, many countries have unveiled strategies aimed at bolstering domestic low-carbon hydrogen production or facilitating imports. Within this context, international trade has emerged as a means of importing hydrogen from regions with low-cost production capabilities. However, investment decisions in the development of international hydrogen markets are moving slowly due to large uncertainties regarding the magnitude of future demand and willingness to pay for hydrogen in key end- use applications.
In this study, we develop a novel modelling framework capable of simulating global hydrogen market equilibrium and international trade scenarios in the long-term future. Our methodology includes the development of supply and demand curves, as well as a global hydrogen trade model that takes into account various supply chain options. Using this framework, we are able to derive quantitative insights into equilibrium supply and demand, pricing dynamics, trade flows, costs, and many more. We apply this framework to investigate the optimal development of hydrogen markets in 2050 under a 1.5°C climate change mitigations scenario. Our findings indicate that new hydrogen sectors could see a global demand surge to 195.2 Mt, with international trade constituting a quarter of this demand.