Manipal Junior College, Manipal prepares meals for 250 students and regular canteen food is prepared as well. The
school buys about 4 cylinders per month which are used only for preparing the mid-day meal.
4 cylinders of LPG = 4 x 710 MJ
= 2840 MJ
Energy required per day = 2840/24 MJ
= 118.33 MJ
Energy obtained per cubic metre of biogas = 22 MJ
Gas requirement to supplement 50% of gas use = 118.33 x
0.5/22 m3
= 2.7 m3
Therefore required size of digester = 2.7/0.7 m3
= 3.85 m3
Therefore 4 m3
digester and 3 m3 gas collector should
provide 50% of the energy requirements.