ANALYSIS OF THE ENERGY EFFICIENCY OF INVERTERS WITH DIFFERENT NOMINAL POWER USING THE REAL LOAD CURVE OF A RIVERSIDE BUILDING

Abstract

There are several ways of designing Solar PV-based autonomous systems for the electricity supply of individual houses, and they can provide for direct current loads, alternating current loads, or both loads (continuous and alternating). In alternating current, the inverter efficiency curve and its nominal power directly influence the loss of the system. Although the manufacturers' manuals present this curve, only some of them detail its impacts since they generally operate with low loads in actual cases. Given this scenario, this work consists of analyzing the energy efficiency of voltage inverters (800, 1500, 2000, and 3000 VA), using the normalized efficiency curve of a series of inverters available on the market, and of an actual load curve as the output power of the inverters to simulate its respective input powers. The load curve, with a two-second sampling, was monitored for a year by the Grupo de Estudo e Desenvolvimento de Alternativas Energéticas in a Solar PV-based autonomous system that supplies a riverside family in the city of Barcarena, Pará. It was concluded, based on the rest periods of the freezer, that inverters with higher nominal power showed lower efficiency for the same amount of energy demanded. The complexity of using consumption reduction as an energy efficiency criterion is also evident, as turning off equipment means reducing the load on the inverter and noticeably making it less efficient.