Stove Automation: Automatic Biogas/LPG switching unit for Kitchen stove.
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Background to this project
Ideas Unlimited developed a Prototype of system that switches automatically between biogas and LPG Gas for a kitchen stove for NIE-CREST. NIE-CREST has their own website detailing all their activities at this URL: www.niecrest.in
About the system

Finished Hardware that is connected to the Biogas plant.
Need for this system:
A typical household kitchen has very limited counter space in kitchen to use two separate stoves for biogas and LPG. This makes adaption of Kitchen Waste Biogas plant slow and difficult.
The LPG stove design differs slightly in the nozzles and burner design because of the higher pressure inside an LPG-Cylinder. Biogas stoves operate on a relatively lower pressure and so have a different kind of design.
In this regard NIE-CREST got a stove design modified with one of the LPG experts so that the same stove can be used for both LPG and Bio-gas and we developed the atomatic system that smartly switches between LPG and Biogas by monitoring the conditions.
A typical Kitchen-Waste Biogas plant developed by NIE-Crest can be placed in the corner of the site of a small 30'X40' house plot and the kitchen waste generated in one day can be used to fuel an afternoon's cooking comforably and more! The biogas plant if maintained continuosly can feed enough gas for cooking one to two time food per day regularly.
Working of the System
Initially the system detects switching on of the gas stove by using a flow sensor switch, and connects the LPG cylinder to the gas stove. LPG also helps in quicker and hassle free ignition of the gas stove. Simaltaenously the system switches on the Air Blower connected to the biogas plant
Then once the stove is ignited within a few seconds, the system switches over to the Biogas line supply instead of LPG.
In case the biogas levels in the biogas plant are insufficient or very low, the system switches over to LPG so the cooking in kitchen is not disturbed. It simaltaneously switchess of the air blower as well.
The system developed as a prototype worked reasonably well,though the biogas tank level system required some improvements.
Details:
The complete system consists of:
- A unit with:
- 2 inlets - One for biogas and one for LPG.
- 1 outlet - Goes to the Kitchen Stove.
- An electrical connection to the air blower next to biogas plant
- An electrical connection to the level sensor in the biogas plant.
- A display on the front panel indicating whats happening inside.
The internal hardware that does the work developed at Ideas Unlimited.
The completed Prototype system.
Two inlets on right side and one outlet on the left.
The front panel visual interface for the system, along with a manual override button.
The inside of the Automatic swiotching unit.
Flow control valves, Flow Sensor switch, Piping and connections
and the electronics associated with it. Developed by Ideas Unlimited, Mysore
Working Sequence: First blower switches on, then LPG line
is connected to the Gas Stove and once stove is ignited and ready
seamlessly switches over to biogas plant. Indicator on left shows the Biogas levels.