Comparative analyses of residential building efficiency for AC and DC distribution networks

The escalating prevalence of rooftop solar PVs and DC powered home appliances are the driving forces for the research in the field of DC distribution at residential level. The current research work presents comparative analyses of AC and DC distribution systems considering various scenarios for the specific purpose of efficiency/energy savings. A modern Bakersfield CA, USA home is considered for the analyses. The loads are classified according to the power demand. Rooftop solar PVs are also included in each residential building. Mathematical equations are devised for the efficiency analysis of residential buildings powered with AC as well as DC. The results reveal strong dependence of the efficiency values on the utilization/types of loads, efficiencies of the power electronic converters (PECs), solar capacity and seasonal conditions, as a function of the time of day. It is concluded that AC system presents better efficiency values as compared to the DC counterpart except during the time periods when solar power is available and when the penetration of variable speed drive (VSD) based loads is high

AC vs. DC distribution efficiency:Are we on the right path?

The concept of DC power distribution has gained interest within the research community in the past years, especially due to the rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts, wherein a definite verdict is still unavailable. Is DC distribution a more efficient choice as compared to the conventional AC system? A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts are analyzed for their approach toward the system upon which they have performed efficiency studies. Subsequently, the paper proposes a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution

Direct current distribution systems for residential areas powered by distributed generation

Power system began its journey with DC power as pioneered by Edison. However, this was soon rivalled by AC power and ultimately DC paradigm found itself quite obsolete, against the ongoing urge to adapt in favor of higher efficiency. AC became the choice for power transfer in all areas of the power system namely generation, transmission, sub-transmission and distribution. However, just as history repeats itself, the fight between these two paradigms of power transfer was reignited as DC proved to be comparable and in certain cases better suited for power transmission eventually leading to the acceptance of HVDC transmission. Ironically, it was again the urge for higher efficiency that led to the shift in the choice and this time it was the AC system which found itself being questioned. DC power has begun a come back

Barriers in the progress of domestic biogas plants in rural Pakistan

The energy crisis has pushed Pakistan way down the economic rankings. More than 70% the total population resides in rural regions. The energy crisis has crippled the lifestyle of the rural class (RC) in many aspects. For rural Pakistan, the energy scarcity, a hurdle in sustainable development, can be eliminated by biogas. Almost every rural family is associated with agriculture and owns livestock animals, therefore self-sufficient in biogas plant’s fuel. Fuel abundance and favourable climatic conditions make energy extraction from biomass facile and fruitful; still there are many reasons that RC is dumped in the energy crisis. In this paper, a survey is conducted in villages of Pakistan to discover the reasons due to which domestic biogas plants have not yet gained their due importance. Institutional, financial, awry planning and social barriers are highlighted at the grass root level in the development of biogas technology in rural Pakistan. In contrast, villages where biogas plants are present, the survey analysis revealed prosperity rendered through savings, reduction in diseases and workload. The paper concludes with an emphasis on the requirement of concrete and comprehensive policy that is capable to deal with the barriers in the route of biogas technology

System efficiency for AC vs. DC distribution paradigms: a comparative evaluation

The birth of electricity witnessed “the battle of currents” between AC and DC as a medium of power transfer. AC won the battle in the first place because of its ability to transform voltage levels. However, with the development of power electronic converters (PECs), DC is striking back. Most of the electronic loads in our conventional AC-based homes are DC by nature. Moreover, the modern concept of energy-efficient variable speed drive (VSD) based loads, i.e. DC-inverter based air-conditioners and refrigerators, require a DC link for their operation. The driving component of all such loads is the PEC. The operational efficiency of PECs depends on the loading which varies throughout the day. This paper presents a mathematical model based on a bottom-up approach to the comparative efficiency analysis of AC and DC distribution systems considering daily load variation. Two topologies are presented where AC and DC distribution systems are compared in terms of efficiency. The first topology (T1) defines a separate/independent converter for each load, whereas in the second topology (T2) loads of a particular class are lumped and driven by a single converter. The results present DC distribution better than AC distribution with an efficiency advantage of 2.28% and 1.57% for T1 and T2, respectively

Efficiency Comparison of AC and DC Distribution Networks for Modern Residential Localities

The paper investigates the system efficiency for power distribution in residential localities considering daily load variations. Relevant system modeling is presented. A mathematical model is devised, which is based on the data from the Energy Information Administration (EIA), USA, for analysis. The results reveal that the DC distribution system can present an equivalent or even better efficiency compared to the AC distribution network with an efficiency advantage of 2.3%, averaged over a day. Furthermore, the distribution systems are compared under various capacities of solar PV accounting for the effect of variation in solar irradiation over time