Now a day, the consumers prefer the devices which have high BEE rating. The BEE rating is the rating provided by the Bureau of Energy to promote the conservation of energy intensity. The rating has become a must in most of the appliances as it provides the energy efficiency of the device. Now, with this small DIY project you can convert any fridge to an energy rated one. The aim of this DIY project is to increase the power rating of the local refrigerator to 3 stars. Generally a mechanical winding timer is used. The timer makes the fridge to go into off state after a specific time and after the time lapse it will be active for that specific time period. Here in this DIY project we are converting this refrigerator's mechanical system to electronic system.
Let’s start converting your fridge to a bee efficient fridge.
Block diagram to convert any refrigerator to an energy rated one
The block diagram gives a simple pictorial representation of how the connections have to be made to work this DIY project. The inputs and outputs of the DIY project can be clearly understood from this diagram. We will start with the input section.
The input section of this DIY project has five inputs. The first three inputs of the DIY project are to set the temperature range and the last two inputs provide the temperature of fridge and freezer. Here in this DIY Project we are considering the refrigerator to be a double- door one.
PIC 16F883, an 8-bit microcontroller from Microchip is used as the controller in the DIY project. It has 28 pins.This is the apt one for consumer applications. It requires 5V power supply for its efficient working. The push buttons (UP, SET, DOWN) provides the digital input to the controller of the DIY project. The digital inputs are used to set the specific temperature desired by the user. The temperature sensors (FRIDGE, FREEZER) provide analog input to the microcontroller. This analog input is to provide the present temperatures of the fridge and freezer. PIC microcontroller gives two output digital output signals. The first output signal from the PIC microcontroller is used to drive the electrical switch, relay. Relay is used to switch the refrigerator from on to off state and vice versa. The other output is for LCD display to display the temperatures of the fridge and freezer.
LM35 is used as temperature sensor in the DIY project. It is an integrated temperature sensor. The output voltage will be proportional to the temperature. The main benefit of this sensor is that no external calibration is required, low self-heating and it provides an accuracy of 0.8°C for the temperature range of 0-100°C. The sensor sensitivity is 10mV / °C. The equation used to convert the output voltage into temperature is given below
Temperature (°C) = Vout * (100 °C/V)
Final View of the DIY Project
Suppose we chose 10°C as the temperature. Using UP and DOWN buttons set the temperature as 10°C. Therefore, the temperature range will be 9-11°C. This will be given as an input to the microcontroller. The two temperature sensors will be monitoring the temperature and the readings will be given to the PIC. When the temperature goes down to 9° C the relay will go off and the refrigerator will go off. When the temperature exceeds 11°C the relay will get on and thus the device will be in on state. This on and off mechanism will ensure the power to be used effectively. The required temperature can be maintained without making the device work full time. The PIC will be providing the necessary outputs to switch the relay between and on and off condition. The LCD will display the temperature of the fridge and freezer.
Here a small example is used to understand you the working of this electronics DIY project. Step by step method of doing this is given below.
Closer view of the components used in the DIY Project
Once it is set, the relay will go off. When relay goes off the machine will go into sleep mode. The temperature sensor monitoring the temperature of fridge and freezer will be providing up to date data to the PIC microcontroller of the DIY Project which act as the controlling unit of the system. If the temperature exceeds the limit the relay goes on and fridge becomes active. During this transient period of sleep and active the power consumption will be low thus helping to save the energy.
Hope this DIY project will be useful for you guys to convert your old fridge to a brand new energy efficient. Remember save energy save money……………………….