☀️ SolSwitch

Smart Solar Grid Manager — Residential Energy Management System

Project Overview

What is SolSwitch and why does it matter?

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Short Description

A residential smart energy management system designed to optimize the use of solar power. Instead of sending surplus energy back to the grid or wasting it when the battery is full, SolSwitch intelligently redirects the excess power to specific household appliances based on user-defined priorities.

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How It Works

The system begins at the Photovoltaic (PV) Array. Energy flows into the Hybrid Inverter, which powers the house, charges batteries, and synchronises with the grid. Once batteries are full and critical loads are met, the EMS starts routing surplus to flexible loads like the boiler, heater, or EV charger — guided by real-time sensor feedback.

System Architecture Scheme

Click any component to learn more about it.

👆 Tap / click on any block for details

☀️ Solar Panels (PV Array) 🔋 Battery Bank LiFePO4 / Lead-Acid Hybrid Inverter DC→AC / Grid Sync 🏭 Utility Grid Main AC Supply Main Electrical Panel Power Distribution 🧊 Critical Loads Fridge, Router, Lights ⚡ Smart Switching Hub SSR Relays / ATS Board 🧠 Microcontroller Raspberry Pi 4 / ESP32 🔥 Boiler Temp Sensor 🌡️ Heater Thermostat 🚗 EV Charger OCPP / PWM ❄️ Air Con Thermostat 📱 App PC / Android DC Power DC ↔ AC ↔ AC Out Modbus / API Always On AC Power Control Feedback Wi-Fi Legend Power flow Data / Feedback Wi-Fi / MQTT

Main Definitions

Key terminology used in this project.

Photovoltaic (PV) Array — The solar panels that convert sunlight into direct current (DC) electricity.
Hybrid Inverter — The central hub that converts DC power from solar panels to alternating current (AC) for home use, manages battery charging, and synchronises with the main electrical grid.
Energy Management System (EMS) — The software and hardware logic (powered by the microcontroller) that decides where to route energy.
Load Prioritisation / Smart Switching — The process of automatically turning on/off specific loads (appliances) in a predefined order when surplus solar energy is available.
Critical Loads — Appliances that must always have power (e.g., Fridge, Internet Router). These are fed directly and continuously.
Flexible Loads / Deferrable Loads — High-power appliances that can be turned on only when there is excess energy (e.g., Boiler, EV Charger, Space Heater).
Feedback System — Sensors (temperature, battery charge level) that tell the microcontroller the state of an appliance so it knows whether to keep powering it or move to the next priority.

Components & How They Work Together

The four pillars of the SolSwitch architecture.

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Power Generation & Storage

Solar Panels generate DC power. The Hybrid Inverter converts it to AC for the home or stores it in the Battery Bank. The power priority order is: Solar → Battery → Grid.

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Continuous Alimentation

The fridge and other critical electronics are connected directly to the Main Panel (critical load sub-panel). They run continuously, drawing power from Solar → Battery → Grid in that order.

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Smart Switching Hub

A custom board with heavy-duty Solid State Relays (SSRs) or Automatic Transfer Switch (ATS) mechanisms. It acts as a gateway to the flexible loads, controlled by the microcontroller.

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Feedback Systems

Boiler: DS18B20 temperature sensor reports water temp. Heater/AC: Room thermostat vs. target temp. EV Charger: OCPP protocol or PWM signal reads charge state.

Microcontroller & Its Functions

Raspberry Pi 4 (or ESP32 for a stripped-down version)

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Data Acquisition

Reads real-time data from the Hybrid Inverter: solar production wattage and battery State of Charge (%).

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Sensor Polling

Constantly reads the feedback sensors — temperatures, EV charge state, room conditions.

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Logic Engine

Core algorithm: If Battery = 100% AND Solar Production > Home Base Load → Enable Surplus Mode.

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Priority Execution

Iterates through the user's priority list. If the boiler temperature is met, it disables the boiler relay and moves to Priority 2 (EV charger).

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Communication Gateway

Runs a lightweight web server or MQTT broker to communicate with the mobile/PC application over Wi-Fi.

Application & Control

Cross-platform web app accessible via PC browser, compiled into an Android App.

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Dashboard

Displays a live animated flow of energy: Solar → Battery, Solar → House, with real-time power indicators.

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Priority Drag-and-Drop

Users drag appliances up or down a priority list. Winter mode: heater on top. Summer mode: AC on top.

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Threshold Settings

Set target temperatures for the boiler, room thermostats, and battery percentage triggers (e.g., "Start routing when Battery > 95%").

Literature & References

The architecture draws upon standard concepts in modern Smart Grid and Renewable Energy Systems.

Keyhani, A. (2011). Design of Smart Power Grid Renewable Energy Systems. Foundational grid architecture and inverter operations for hybrid microgrid setups.
Papadopoulou, E. (2012). Energy Management in Buildings Using Photovoltaics. Integration of PV systems for optimal energy efficiency and load matching.
Jiménez Carrizosa, M. Smart Energy Management for Smart Grid. Algorithms and feedback loops for Home Energy Management Systems (HEMS).
Ma, Y. & Li, B. Hybridized Intelligent Home Renewable Energy Management System for Smart Grids. Frameworks for intelligent appliance-level load scheduling.