Consensus-Based Distributed Optimization of Generation Dispatch of Multi-Area AC Systems Interconnected by DC Lines

This paper is dedicated to solving the distributed optimization of generation dispatch of multi-area AC systems interconnected by DC lines, which aims at minimizing the total generation cost while satisfying the power supply demand balance and generation capacity constraints. A novel nodal loss formula which derived from the branch active power flow equation is proposed based on phase angle and impedance to improve the system economy. A distributed algorithm based on consensus is built to solve the generation dispatch problem. It has a great effect on improving convergence effect and rate of the system. The control strategy is used on the structure of multi-area interconnection, which improves the reliability of power supply and guarantee the power quality. The study was conducted using three area AC systems interconnected by DC lines. The simulation results show that the proposed generation dispatch method is reliable in convergence. It provides an effective tool for distributed optimization of generation dispatch of multi-area AC systems interconnected by DC lines.

Performance Improvement of Membrane Energy Exchanger using Ultrasound for HVAC Application

Air conditioning (AC) systems consume the maximum proportion of the total electricity used in the building sector. The demand of AC systems is expected to increase exponentially in the coming years due to various reasons such as climate change, increasing affordability and increase in living floor space. Membrane-based liquid desiccant AC system along with energy recovery ventilating equipment is considered as a prospective alternative to the conventional air conditioning system (CACS) and has the potential to meet the increasing current and future AC demand in a sustainable manner. Its efficiency and energy saving potential with respect to CACS depends on the performance of the membrane-based dehumidifier, regenerator and energy recovery ventilating equipment which are commonly referred to as membrane energy exchangers (MEEs). MEE is an indirect exchanger type in which the working streams are separated by a porous membrane. This intermediate membrane creates an additional resistance for the heat and mass transfer process in the MEE. To reduce the resistance, this study experimentally and numerically investigates the influence of ultrasound on the performance of the MEE for dehumidification, humidification (applicable for membrane-based evaporative cooling and desiccant regeneration devices) and energy recovery processes. It is found that the vibration due to ultrasound has the potential to improve the effectiveness of the MEE by 55% in the dehumidification process and by 65% in the humidification and energy recovery processes.