Final Program EXPRES 2012 - Conferences

Toward Future: Positive Net-Energy BuildingsM. Bojic * J. Skerlic * D. Nikolic * D. Cvetkovic * M. Miletic **University of Kragujevac /Faculty of Engineering, Kragujevac, Serbiabojic@kg.ac.rs, jskerlic@kg.ac.rs, danijelan@kg.ac.rs, dragan_cw8202@yahoo.com, marko.m.miletic@hotmail.comAbstract—For a positive net energy building (PNEB), thepaper presents its need, definition and elements. The mostimportant is that the PNEB should provide the maximumthermal comfort with a minimum of energy, primaryenergy, and exergy consumption, and a minimum of CO2emission throughout its life. Then, the paper presents thesoftware for a energy simulation and optimization of PNEB.After that, the paper describes the five examples connectedto the PNEB. The first example is a simulation of aresidential PNEB, second the optimization of thephotovoltaics in the residential PNEB, third the descriptionof an the building as a power plant initiative, fourth thedescription of an office PNEB, fifth description of an archivePNEB and finally a description of a headquarter PNEB.ZNEB, show software for their design and give theirseveral examples.DEFINITIONSThe schematic of a PNEB is shown in Fig.1.INTRODUCTIONDaniel M. Kammen, Director of the Renewable andAppropriate Energy Laboratory, University of California,Berkeley wrote the following in Nature[1]. “By 2020.humankind needs to be solidly on to the path of a lowcarbonsociety — one dominated by efficient and cleanenergy technologies. Several renewable technologies areready for explosive growth. Energy-efficiency targetscould help to reduce demand by encouraging innovationssuch as PNEBs and electric vehicles. Research into solarenergy — in particular how to store and distribute itefficiently— can address needs in rich and poorcommunities alike. Deployed widely, these kinds ofsolutions and the development of a smart grid wouldmean that by 2020 the world would be on the way to anenergy system in which solar, wind, nuclear, geothermaland hydroelectric power will supply more than 80% ofelectricity.”Globally, the drive for PNEB is necessity and urgencyto decrease carbon emission, and relive energy shortage.Several worldwide targets are established. First, theEnergy Performance of Buildings Directive of EU statesthat all buildings built after 31 December 2018 will haveto produce their own energy onsite [2]. Second, frombeginning of 2020 in USA, all new Federal buildings willbe designed to consume zero-net-energy and be zero-netenergybuildings (ZNEBs) by 2030 [3]. Third, to progresswith the development and adoption of high performancebuildings in USA, there is the Net Zero EnergyCommercial Building Initiative. The initiative aims toachieve marketable net-zero energy buildings by 2025through public and private partnerships [4]. Finally, UKGovernment sets out improvements to energyrequirements in Building Regulations to include that allnew homes has to be ‘zero carbon’ by 2016[5].The objective of this paper is to introduce definitionsand general characteristics of PNEB that go beyondFig.1 Schematic of a PNEBA. Ordinary Definitions [6]Positive-Zero Site Energy — PNEB generates moreenergy than it consumes. It usually produces electricalenergy through PV modules and is connected to the grid.The building may either consume electrical energy fromthe PV modules or from the grid. The generatedelectrical energy may either feed the building or the grid.The electric energy supplies the grid when there is theelectrical energy surplus. When there is electrical energyshortage the grid supplies electrical energy to thebuilding. The ‘‘positive-net’’ concept means that yearlythe excess electrical energy sent to the grid is larger thanthe amount received from the grid. The PNEB uses thepower grid as an electrical storage battery.Positive-Zero Source Energy — A building thatproduces and exports more energy as the total energy itimports and uses in a year, when accounted for at thesource. "Source energy" refers to the primary energyrequired to generate and deliver the energy to the site. Tocalculate a building's total source energy, imported andexported energy is multiplied by the appropriate site-tosourceconversion multipliers.Positive-Zero Energy Costs — A building where theamount of money a utility pays the building's owner forthe renewable energy the building exports to the grid is49