Hot Water Utilization Enhancer For Solar Water Heater

The Hot Water Utilization Enhancer system is built around an Arduino Uno, which acts as the central processing unit to monitor environmental conditions and control water flow. The primary sensor is an LDR (Light Dependent Resistor), designated as LDR1, which detects ambient light levels to infer whether it is a sunny day or an overcast, cloudy day. The Arduino reads the analog voltage changes across the LDR circuit to determine the solar intensity. Powering the system requires stepping down mains power using a 230V primary to 15V AC 1A transformer. The alternating current is converted to direct current via a full-bridge rectifier (BR1) and smoothed using a 1000uF 35V capacitor alongside a 1uF 25V capacitor. Dual voltage regulation is achieved through a 7812 voltage regulator and a 7805 voltage regulator to supply the correct operating voltages to the logic and switching components, while diodes D2 and D3 provide necessary reverse-current protection. Indicator LEDs give visual feedback on system status and power. When the Arduino detects low light conditions—signaling winter or cloudy weather where solar heating is suboptimal—it triggers a digital output pin connected to a 12V single changeover relay. This relay acts as an electrically isolated switch that controls a 12V solenoid valve placed at the cold water inlet of the solar water heater. By keeping the solenoid closed during these periods, the system prevents cold water from entering and unnecessarily mixing with and cooling down the stored hot water, thereby optimizing overall thermal efficiency.