Design of Zero Energy Consumption System for Small DC Residential Home Based on Off-Grid PV System

Abstract

This research presents the design of a zero energy consumption system (ZECS) based on off-grid photovoltaic (PV) system for small DC system whose load demand is less than 1 kWh/day. This system consists of 3 parts: 300 W PV panel, energy conversion or solar charger, and 12 V 200 Ah energy storage. The used electrical utilizing system consists of 3 types: 20 W LED lighting system, 35 W fan for air cooling system, and 100 W electrical boiler or heating system, whose average load requirement is 0.795 kWh/day. This research defines 6 key sustainability parameters and key performance indicators in order to evaluate the benefits of ZECS, which are design, energy security, system availability, efficiency, environment and investment. The result has been analyzed and it was found that ZECS can achieve more than 80% of the energy conversion efficiency and it can operate for 2 days without charging the battery. The battery charging and discharging from PV are demonstrated to confirm ZECS energy security. The utilization ratio or the energy that required per one square meter is less than 50 Wh/m2. DC ZECS and DC electric appliances are available, affordable and easy to be maintained. ZECS is designed in order to provide the electricity for low-income people in remote areas, and its social benefits are more important than the return on investment. It can be concluded that DC utilizing system is reliable for ZECS which can benefit to apply this system in remote area where it cannot connect to the grid.