A novel energy harvesting mechanism and its design methodology for underwater gliders using thermal buoyancy engines

Underwater gliders are becoming popular in ocean exploration. However, the main development limitation of underwater gliders is still around energy. This paper proposes a new-type energy harvesting mechanism and explores its design methodology for the gliders using thermal buoyancy engines. With the temperature difference in the ocean, the thermal buoyancy engine changes the buoyancy of the glider and drives the glider to ascend and descend through the water and drive a turbine behind to harvest energy. Based on this harvesting mechanism, firstly, a new-type thermal engine with high ballast capacity is developed with patent applied. Secondly, a dedicated turbine design and optimization method based on modified Blade Element Momentum (BEM) theory has been developed to maximize the energy harvesting capability

Smart security door system using SMS based energy harvest

Over the last decade, different studies have been conducted to increase security to identify sensor technology and provide alternative energy with other energy harvest techniques such as vibration energy harvester and sun energy harvester. There is no combinational approach to utilize the door to create energy and use it for security measures in the literature, making our system different and unique. This proposed system comprises the security and the energy harvest; the security section utilizes a motion detector sensor to detect intruders. For instance, the magnetic door lock type firmly locks the door, which can only open with a generated password. On the other side, the energy harvest section utilizes the door motion to generate electricity for the system, which solves power shortage and limited battery life issues. Moreover, this study includes a GSM module that allows authorized owners to receive a generated password as a security enhancement. This design mainly focuses on improving or optimizing the conventional security doors' overall performance as sliding door, panel door, or revolving door. The experimental results show the system efficiency in terms of power generation and the time needed to authenticate the property owner. Notably, the power generator can generate electricity more rapidly, while the needed time to receive the mobile device's security code is around 3.6 seconds

Actuator disk theory and blade element momentum theory for the force-driven turbine

The Actuator Disk Theory and the Blade Element Momentum Theory (BEMT) are widely applied in the field of tidal and wind turbine design. The current BEMT turbine design method is based on the assumption of achieving the Betz limit when the axial induction factor (a) reaches 1/3. But this only applies to turbines driving by a constant velocity, i.e. the velocity-driven turbine. This paper introduces a new type of turbine, namely the force-driven turbine which by its name is driven by a constant force. This paper then expanded the actuator disk theory for the force-driven turbine and identified the relationship between the axial induction factor with the power and the energy yield of the force-driven turbine. According to the relationship, this paper proposes a new BEMT turbine design method for the preliminary design of the force-driven turbine. Then, a case study is conducted to demonstrate and verify the developed method. The case study shows the newly developed method can be used to quickly and effectively identify the optimum design for force-driven turbines