Natural ventilation of buildings is the flow generated by temperature differences and by the wind. The governing feature of this flow is the exchange between an interior space and the external ambient. Although the wind may often appear to be the dominant driving mechanism, in many circumstances temperature variations play a controlling feature on the ventilation since the directional buoyancy force has a large influence on the flow patterns within the space and on the nature of the exchange with the outside. Two forms of ventilation are discussed: mixing ventilation, in which the interior is at an approximately uniform temperature, and displacement ventilation, where there is strong internal stratification. The dynamics of these buoyancy-driven flows are considered, and the effects of wind on them are examined. The aim behind this work is to give designers rules and intuition on how air moves within a building; the research reveals a fascinating branch of fluid mechanics.

The fluid mechanics of natural ventilation

The increasing installed area of solar technologies around the world gives us an idea about the unlimited potential available in solar energy. This combined with the rising fossil fuel prices and frequent power outages, favor decentralized power generation among domestic consumers and small industries. However, the low energy of the solar PV module, the low exergy of the solar flat plate thermal collector and limited usable shadow-free space on building roof-tops could be overcome by the high overall (electrical and thermal) efficiency of a solar Photovoltaic Thermal (PV/T) system, which combines the electrical and thermal components in a single unit area. This paper gives a brief overview of the different solar flat plate PV/T technologies, their efficiencies, applications, advantages, limitations and research opportunities available.

Flat plate solar photovoltaic–thermal (PV/T) systems : A reference guide

In this manuscript, we provide a structured and comprehensive overview of techniques to integrate machine learning with physics-based modeling. First, we provide a summary of application areas for which these approaches have been applied. Then, we describe classes of methodologies used to construct physics-guided machine learning models and hybrid physics-machine learning frameworks from a machine learning standpoint. With this foundation, we then provide a systematic organization of these existing techniques and discuss ideas for future research.

Integrating Physics-Based Modeling with Machine Learning: A Survey

The concept of building-integrated photovoltaic/thermal (BIPV/T) systems emerged in the early 1990s. It has attracted increasing attention since 2000 due to its potential to facilitate the design of net-zero energy buildings through enhanced solar energy utilisation. This article presents a comprehensive review of the BIPV/T technology, including major developments of various BIPV/T systems, experimental and numerical studies, and the impact of BIPV/T system on building performance. The BIPV/T systems reviewed here are: air-based systems, water-based systems, concentrating systems and systems involving a phase change working medium such as BIPV/T with either heat pipe or heat pump evaporator. This work provides an overview of research, development, application and status of BIPV/T systems and modules. Finally, research needs and opportunities are identified.

A review of research and developments of building-integrated photovoltaic/thermal (BIPV/T) systems

People are becoming more and more sensitive to the ecological consequences of global warming and environmental devastation. The objective is to replace the use of fossil fuel energy with renewable forms of energy. In the field of building construction, this leads to a new legislation frameworks and radical changes in how we design our buildings. The use of renewable in the building envelope is much varied and opens many opportunities for creative designers. Many architects have already integrated PV successfully in their buildings. This paper reviews the present day application of BIPV and BIPV-T technologies. In addition to it thermal modeling, energy and exergy analysis of BIPV and BIPVT system are also discussed. This study also reviews the recent developments of the technology worldwide.

Thermal modeling, exergy analysis, performance of BIPV and BIPVT: A review

https://cronfa.swan.ac.uk/Record/cronfa46445/Download/0046445-13122018164928.pdf

A reduced order model for turbulent flows in the urban environment using machine learning

A preceding companion article introduced the slot jet approach for large-scale quasi-steady modelling of a downburst outflow. This article extends the approach to model the time-dependent features of the outflow. A two-dimensional slot jet with an actuated gate produces a gust with a dominant roll vortex. Two designs for the gate mechanism are investigated. Hot-wire anemometry velocity histories and profiles are presented. As well, a three-dimensional, subcloud numerical model is used to approximate the downdraft microphysics, and to compute stationary and translating outflows at high resolution. The evolution of the horizontal and vertical velocity components is examined. Comparison of the present experimental and numerical results with field observations is encouraging.

Proposed large-scale modelling of the transient features of a downburst outflow

The response of an overhead electrical power transmission line to two types of wind forcing

This article synthesizes the literature on the meteorology, experimental simulation, and wind engineering ramifications of intense downburst outflows. A novel design of a large-scale test facility and experimental evidence of its validity are presented. A two-dimensional slot jet is used to simulate only the outflow region of a downburst. Profiles of mean velocity and turbulence quantities are acquired using hot-wire anemometry. Comparison with the literature provides empirical evidence that supports the current approach. A geometric analysis considers the validity of applying a two-dimensional approximation for downburst wind loading of structures. This analysis is applicable to power transmission lines in particular. The slot jet concept can be implemented in a large boundary layer wind tunnel to enable large-scale laboratory experiments of thunderstorm wind loads on structures.

William E. Lin

Papers

A reduced order model for turbulent flows in the urban environment using machine learning

Proposed large-scale modelling of the transient features of a downburst outflow

The response of an overhead electrical power transmission line to two types of wind forcing

Large-scale quasi-steady modelling of a downburst outflow using a slot jet

Energy modeling of photovoltaic thermal systems with corrugated unglazed transpired solar collectors – Part 1: Model development and validation