AC Versus DC Distribution SystemsDid We Get it Right?

Hammerstrom, Donald J.

doi:10.1109/pes.2007.386130

Cited by 185 publications

(145 citation statements)

References 11 publications

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“…A varying amount of power conversions is required between the electronic devices and the AC grid, and each conversion induces power losses. DC power distribution has been previously found more beneficial in buildings with distributed generation [19], [21] [84]. These things have re-introduced the idea of utilizing DC grids within buildings.…”

Section: Discussion and Analysismentioning

confidence: 99%

“…Therefore, a simulation was used to compare 12 VDC, 24 VDC, 48 VDC and 230 VAC power systems. The selection of simplifications influenced the results of the simulations, as has been previously pointed out [21]. As the efficiencies of the DC ballasts, LED drivers and all ATX computer power supplies and ventilation systems were taken directly from datasheets, rather than measured, the results are based on the assumption that the specifications of the devices match the data sheets.…”

Section: Discussion and Analysismentioning

confidence: 99%

“…With a DC grid the distributed generation can be connected with less conversion stages and it is possible to connect battery backup directly to the DC bus [84]. These things have led to the reintroduction of the idea of using DC distribution within buildings [19]- [21] [84].…”

Section: Comparison Between Ac and DC Systemsmentioning

confidence: 99%

“…Thus, by substituting the existing AC supply grid with a DC grid it may be possible to gain energy savings, as less power conversion stages are required. According to previous studies [19]- [21], DC distribution is more efficient if there is local distributed generation included in the system. However, the power supply has been based on AC technology since the early 20 th century [22] and most of the existing devices have been designed for it.…”

Section: Introductionmentioning

confidence: 98%

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Electrical efficiency study of alternating current and direct current power topologies in office building with integrated photovoltaics in Matlab-Simulink environment

Viitanen

Halonen

2014

Journal of Renewable and Sustainable Energy

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Ene rgy e ffic ie nt l igh t ing syst e ms in buil dings w it h int e grat e d ph o t o vo l t aic s J a nne V i i t a ne n D O C T O R A L D I S S E R T A T I O N SAalto University publication series DOCTORAL DISSERTATIONS 18/2015 Energy efficient lighting systems in buildings with integrated photovoltaics Janne Viitanen A doctoral dissertation completed for the degree of Doctor of Science (Technology) to be defended, with the permission of the Aalto University School of Electrical Engineering, at a public examination held at the lecture hall S1 of the school on 6 March 2015 at 12. Aalto University School of Electrical Engineering Department of Electrical Engineering and Automation Lighting Unit AbstractThe goal of this thesis was to study how a building integrated photovoltaic system, choice of lighting technology and the selected system voltage affect the energy efficiency of an office building. The quality of the lighting was considered also, as it is essential that users accept the lighting.The energy production of photovoltaic system (PV) was evaluated in Southern Finland through onsite PV measurements from several different compass points and tilt angles during 2010-2013. Based on the measurements, the PV system was sized to provide energy for lighting and office appliances. The energy efficiency of the devices had considerable effect on the sizing of the PV system. The seasonal variations in the PV production were considerable, as only few per cent of the summer time insolation was available during the winter.The energy efficiency and quality of lighting was studied. Fluorescent lighting (FL) and LED lighting were compared, as they are the most used options in offices today. Lighting measurements and a user study was conducted. Different illuminance levels and correlated colour temperatures (CCT) were studied. The studied parameters included glare, reading task performance, identification of detail, colour naturalness and pleasantness, illuminance level sufficiency and pleasantness, pleasantness of the lighting in general and naturalness of the shadows. The subjects also set their own preferred illuminance levels and CCTs. No major differences were found in the subjective preferences at equal illuminance levels between luminaire types. On average, an illuminance level around 600 lx and a CCT around 4000 K were preferred. LEDs were found more energy efficient than FLs and the difference increased when the luminaires were dimmed.In the last part of the research the electricity consumption of an office building was compared with system voltages 12 VDC, 24 VDC, 48 VDC and 230 VAC through computer simulations in a Matlab-Simulink environment. It was found that 230 VAC was the most energy efficient option as a general system voltage, with the selected components and system variables. The 24 VDC was the most energy efficient option with fluorescent lighting and the 48 VDC with LED lighting, if only the lighting system was considered. Aurinkosähkön tuotantoa Etelä-Suomessa tutkittiin mittausten avulla eri il...

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Section: Discussion and Analysismentioning

confidence: 99%

Section: Discussion and Analysismentioning

confidence: 99%

Section: Comparison Between Ac and DC Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Electrical efficiency study of alternating current and direct current power topologies in office building with integrated photovoltaics in Matlab-Simulink environment

Viitanen

Halonen

2014

Journal of Renewable and Sustainable Energy

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“…The author assumed 70-75% efficiency for AC-DC converters and 90% efficiency for the centralized rectifier and accounted for some efficiency improvements from switching from AC-powered to DC-internal appliances, such as refrigerators. In [12] author created a model that compared DC versus AC distribution in a residential building with and without an on-site DC power source. In addition, in [13] a model has been proposed that estimated the costs and energy use of residential power distribution for five scenarios, including AC distribution, hybrid AC and DC distribution, and DC distribution for various voltage levels.…”

mentioning

confidence: 99%

Voltage Standardization of DC Distribution System for Residential Buildings

Chauhan¹,

Rajpurohit²,

Hebner³

et al. 2015

JOCET

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Abstract-The renewable energy sources (RES) such as photovoltaic (PV) are basically DC power sources. In the present scenario, the integration of RES to power distribution infrastructure necessitates the DC-AC converter. Moreover the DC loads in the buildings is ever increasing with the use of CFL, LED, refrigerator, TV, fan, air conditioner, laptop, and other electronics in workplaces and homes. This forced to introduce the internal or external AC-DC converter to tie the DC load to AC distribution infrastructure of existing power system. This is further adding losses and complexity. This AC-DC converter stage can be reduces up to a certain level by DC distribution system (DCDS). Secondly the multi voltage rating of RES and DC load insists to introduce DC-DC converter in DCDS infrastructure. This will further add losses and complexity. In this paper a standard voltage level DCDS is proposed to minimize the system losses, complexity. To verify the simulated results in terms of building load and converter losses, a DCDS equipped with different energy sources like solar panel (PV), public utility (PU) and battery bank (BB) is compared with ACDS.

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