Floating offshore wind turbine (FOWT) has been a hot research topic in recent years due to its great potential in deep sea wind energy harvesting. However, the floating platforms will introduce additional degrees of freedom to the system, which results in much more ultimate and fatigue loads onto the wind turbine structure compared with fixed bottom types. The load issue has been the major design challenge in developing FOWTs. In this paper, we report a novel semi-submersible supporting platform design, named MUsupport, aiming to improve the dynamic responses and reduce loads for FOWTs. The proposed semi-submersible MUsupport is mainly composed of one main column attached to the tower and four offset columns. Particularly, instead of simply filled with ballast water, the four columns act as four tuned liquid column dampers (TLCDs), and the oscillating liquid inside the TLCDs is supposed to help improve the dynamic responses of the semi-submersible platform, thus reducing the loads. The sizing of these TLCDs are determined by frequency analysis, and the detailed structural properties for MUsupport are described in this paper. Additionally, in order to better study the damping effects of the TLCDs, the dynamic model of MUsupport FOWT in the pitch-surge-heave plane is derived based on the Lagrangian approach, and free decay simulation test is performed. It can be observed from the results that the introduction of TLCDs will bring more damping to the system dynamics, which is helpful for FOWT load reduction. Note that this is only preliminary study, and future works will comprehensively investigate its hydrodynamic and mooring behaviors of MUsupport, and aero-hydro-servo-elastic numerical simulations or experimental tests should be performed to further verify its effectiveness.

Broadband underwater acoustic signal direction of arrival (DOA) estimation method is an important part of underwater array signal processing. The commonly used array signal DOA estimation algorithms due to the restriction of algorithm principles, are unable to process broadband array signal effectively, at the case of the arriving signals have strong correlation, small sampling snapshots or small arrival angle. Therefore, we need a new efficient algorithm to meet the increasing demand of broadband under water acoustic signal processing method. This paper makes use of the broadband acoustic signal similarity of joint sparsity in signal spatial domain received by underwater sonar arrays, establishes the whole space grid covering all broadband frequency domain slices. On the basis, the global sparsity of each frequency domain slice is combined with sparse element extraction class algorithm. By integrating the energy of signal on each slice, the spatial sparsity of each slice is obtained, from which we can get the directions of the arriving broadband wave signals. Through the simulation analysis and experimental verification on lake, we can be see that: The SDJS algorithm improves the performance and signal processing capability of the algorithm compared with the traditional algorithms. Therefore SDJS algorithm has a widely range of research value and application space.

Recent years have seen rapid development in offshore wind technology. Particularly, floating offshore wind turbines possess great potential in deep water coastal places around the world, though they are now still in the demonstration phase. At the same time, the unused wave energy is also abundant at the sites of offshore wind farms, especially those in deep sea regions. Collecting wave energy in offshore wind farms might benefit both total energy production and reduce maintenance cost. Therefore, integrating offshore wind turbine with wave energy conversion devices could be a good idea to achieve higher efficiency and lower cost. In this paper, we report a combined wind and wave energy power generation concept called WindOWC, which constits of a 5MW wind turbine and three oscillating-water-column (OWC) wave energy converters (WECs). The wind turbine is mounted on a semi-submersible floating platform, which is similar to OC4-semibsubmersible, and the OWCs are located in its three offset columns. In this design, the wind turbine and WECs share the same supporting platform and the power transmission system, thus is expected to reduce the cost of energy. Also, it is possible the OWCs may improve the platform dynamic performance by providing positive damping through controlling the air turbine rotational speed. In this work, we describe the geometry properties of the proposed WindOWC concept and conduct preliminary hydrodynamic analysis using potential flow theory. The ANSYS AQWA is used to obtain the system dynamic responses in frequency and time domain, respectively. The OWC dynamics and expected positive damping from them will be investigated in the future.

In order to simplify the manufacture and improve heat transfer performance of shell-and-tube heat exchangers (STHXs), we have invented a combined multiple shell-pass STHX with continuous helical baffles. The novel combined multiple shell-pass STHX with continuous helical baffles (NOVEL STHX) is compared with the conventional STHX with segmental baffles by Computational Fluid Dynamics (CFD) method. The numerical results show that, under the same mass flow rate M and the same overall heat transfer rate Q m in the shell side, the overall pressure drop DP of the NOVEL STHX is lower than that of the STHX with segmental baffles by about 13%. The heat transfer rate Q m of the NOVEL STHX is higher than that of the STHX with segmental baffles by about 6% under the same overall pressure drop DP . The NOVEL STHX might be used to replace the conventional STHX with segmental baffles in industrial applications to save energy, reduce cost and prolong service life.

A detailed model of the Net Zero Energy Town House in Toronto is developed in TRNSYS, incorporating a ground source heat pump integrated with an in floor radiant heating system. In order to minimize the heating and cooling loads, the building envelope is well insulated with the exterior walls having an R-60 insulation value. Much of the work done previously on the use of thermal mass in buildings has been experimental in nature and has focussed mainly on conventional brick construction in hot climates such as Asia and Africa. This research will analyze the impact of using thermal mass with a building envelope that is highly insulated, and of a light construction, such as that used in Low Energy or Net Zero housing. Furthermore, this analysis would also evaluate the impact of using thermal mass in a cold climate such as that found in Canada. The simulations showed that, for colder climates, thermal mass can replace some of the insulation and still provide superior results. Also the impact of thermal mass was found to be more significant during the winter season than summer for Toronto.