Air conditioning with TBAB clathrate hydrate slurry as distribution fluid

At the moment, the worldwide demand for air conditioning is rapidly growing, and it is expected to exceed the demand for space heating by the 2060s. However, traditional refrigerants such as CFCs and HCFCs are regulated or phased out by the Montreal and Kyoto protocol. Secondary loop refrigerant systems use less of these harmful refrigerants...

Advanced NH3 based absorption refrigeration cycles: Modelling of the ionic liquid based double-effect cycles

Absorption refrigeration cycles are energy saving as they can be driven by waste heat instead of electricity. By doing so, they reduce the use of fossil fuels, resulting in a reduction of emissions. However, many challenges exist for the traditional working fluids of the cycle, such as the crystallization problem of the water-lithium bromide...

Modelling of Vortex Generators within the Integral Boundary-Layer Theory

One of the most commonly used flow control techniques to trim the aerodynamic performance of wind turbine blades are vortex generators. This passive device, which does not require any active energy, is gaining an increasing interest in this sector especially due to the trend of increasing wind turbine size. Vortex generators are a flow control...

Airfoil Design for Vertical Axis Wind Turbines: Including Correct Simulation of Flow Curvature

In the past, the vertical axis wind turbine (VAWT) lost the competition to its horizontal axis counterpart, having (wrongfully) presumed disadvantages like increased fatigue and low efficiency. Little research and development into the VAWT led to a large gap between the maturity of technology of both turbine types. Now that due to modern...

Analysis of an Actuator Disc under Unsteady Loading: Validation of Engineering Models using Experimental and Numerical Methods

Wind turbines operate in the earth's atmospheric boundary layer - an environment where the climate is turbulent and unsteady. In addition, wind turbines usually operate in clusters (wind farms) and are thus subjected to the unsteady wakes generated by upstream turbines. Because of the unsteady inflow, wind turbines suffer from structural fatigue...

Enhancing the Features of Vertical Axis Wind Turbines with Active Flap Control and Airfoil Design

In recent years, the research on Vertical Axis Wind Turbines (VAWTs) have been paving the way for the very large-scale (10-20 MW) floating offshore applications. For a cost effective utilization, VAWTs need to deliver superior aerodynamic and structural performance. Nowadays, the complex ow phenomenon of VAWTs have been better understood and the...

A numerical investigation of using flap control on VAWTs

The renewable energy need facilitates the development of offshore wind power. The abundant wind resource has pushed the wind farms into deep water sites. The floating VAWT concept is emerges as the times require. This research is part of Deepwind concept development. The project focuses on verifying the feasibility of using flap control to...

3D Lagrangian VPM-FMM for Modelling the Near-Wake of a HAWT: The development of a stable, accurate, and efficient numerical solver for large-scale wind energy purposes

Traditionally, the design of the Horizontal Axis Wind Turbine (HAWT) has relied on momentum-based methods such as the Blade Element-Momentum (BEM) models. With the growth of computational power, optimization of wind turbines by using Computational Fluid Dynamics (CFD) for the explicit wake modelling is becoming more mainstream. Wake modelling is...

Dynamic Stall on Vertical Axis Wind Turbines: Creating a benchmark of Vertical Axis Wind Turbines in Dynamic Stall for validating numerical models

Cost Model for Floating Multi-Megawatt Vertical Axis Wind Turbines: With a Focus on the DeepWind Concept

In an effort to achieve economic sustainability, the major challenge for offshore wind remains to bring down costs by approximately 35 % before 2020. With wind farm sites going into deeper waters, further from shore, with more difficult bottom conditions and rougher wave climate, costs are rising faster than the improvements in the technology...

Experimental and numerical study on harmonically pitching airfoils with morphing trailing edge flaps

Structural Optimization Of A Vertical Axis Wind Turbine With Aeroelastic Analysis

Currently, the price per kW of offshore wind energy is 55% larger than onshore [38, 52]. Of this price, the rotor corresponds to 22%. To reduce the price of wind energy, it is necessary to investigate wind turbine concepts with scales above 10 MW. The commonly known Horizontal Axis Wind Turbine (HAWT) requires offshore a large support structure....

Time-resolved 3D PIV analysis of a laminar separation bubble on an unsteady pitching airfoil

In the last years the interest in small unmanned air vehicles (UAVs) has increased. Due to technological improvements, miniaturisation of UAVs is possible in different type of aerial vehicles, varying from airplanes to helicopters. Different from airplanes, helicopters have continuous airfoil motion, which introduces aerodynamic complications,...