The currently developing concept of a Net Zero Energy Building introduces new challenges and researchproblems. The calculation of a net zero energy balance is heavily influenced by the energy carrierweighting factors that are chosen, which can deeply influence the future energy market towardsadopting specific energy technologies. The following paper proposes an analysis of different definitionsand conventions for Net Zero Energy Buildings that employ different calculation methodologies andapply different weighting factors to an Italian case study. The case study, which is called “the LeafHouse”, is one of the first examples of a nearly net zero energy building in Italy. A building simulationand model calibration were performed using monitored data. Energy balances were calculated for thecase study. Scenarios for a building redesign were then proposed, with the aim of reaching an electricitytarget of net zero energy. Reaching a primary energy building balance of net zero is easier when usingsymmetric weighting because it allows renewable energy to account for avoided national mix energygeneration. The results show that symmetrical balances are nearly fulfilled for the existing building andasymmetrical ones are below zero. In the redesign scenarios, the symmetrical weighting scenariosexceed the zero target by 34.10 and 20.83 MWh/year. The asymmetrically weighted balances show avariable trend in that auto-consumption and high load-matching are highly favourable because thetheoretical ‘zero auto-consumption’ scenario would yield the worst result and would be the only onebelow the Net Zero threshold. Although symmetric weighting approaches could be viewed as robustphysical approaches for renewables (e.g., the primary energy conversion factors for PV are usually closeto 1), they can become a heavy burden during the market development of renewable energytechnologies, highly favouring auto-consumption and energy storage to minimise energy import fromthe grid.
|Numero di pagine||13|
|Rivista||RENEWABLE & SUSTAINABLE ENERGY REVIEWS|
|Stato di pubblicazione||Published - 2015|
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