Understanding the potential for electricity savings and assessing feasibility of a transition towards DC powered buildings

摘要

Advances in semiconductor power electronics and growing directcurrent (DC) loads in buildings have lead researchers to reconsiderwhether buildings should be wired with DC circuits toreduce power conversions and facilitate a transition to efficientDC appliances. The feasibility, energy savings, and economicsof such systems have been assessed and proven in data centersand commercial buildings, but the outcomes are still uncertainfor the residential sector.In this work, we assess the technical and economic feasibilityof DC circuits using data for 120 homes in Austin, Texasto understand the effect of highly variable demand profiles onDC-powered residences, using appliance-level use and solargeneration data, and performing a Monte Carlo simulation toquantify costs and benefits.Results show energy savings between 10–21 % when solarPV is distributed to all home appliances. When battery storagefor excess solar energy is considered, these savings increaseto 13–23 %. At present DC equipment prices, converting allequipment to DC causes levelized annual costs of electricity tohomeowners to roughly double. However, by converting onlyhomes’ air conditioning condensing units to DC, the costs ofimplementing DC circuits are greatly reduced and home energysavings of 7–17 % are generated.In addition to quantifying savings, we find major nontechnicalbarriers to implementing DC circuits in homes. Theseinclude a lack of standards for such systems, a relatively smallmarket for DC appliances and components, utility programsdesigned for alternating current (AC) power, and a workforceunfamiliar with DC. Experience with DC is growing in othersectors, and with time this will be transitioned to a broaderaudience of engineers, electricians, and building inspectors toensure that not only are the systems themselves safe, but thatthe image of direct current circuits becomes less foreign overtime. Direct current may very well have a place in the residentialsector, and research and development should continue toexplore other potential benefits that might make a stronger casefor a more widespread transition to what now appears a promisingtechnology.