Date: 17/05/2022
Introduction:
Vigyan Ashram has developed three different models of solar dryer and comparison of dryer with respect to efficiency and quantity of substrate is a task to perform.
Objective:
Comparative study of three dryers with different samples.
Procedure:
- The first sawdust and water were taken as sample to see the difference between the three dome dryers.
- Mix 2 kg of sawdust and 2 kg of water in a tray and place in each dryer for drying.
- When placing the samples in dryer, placed one more sample in the open sun drying for comparison.
- Checked the temperature at 11:00 am of each dryer before drying the sawdust.
- Then checked the temperature of each dryer in 3 hours.
- After 6 hours weighed the sawdust in each dryer.
- Then checked how much water remains in sawdust of each dryer.
- The drying percentage is calculated from the amount of water evaporated.
Observation Table:
Table No.1 Data collection of drying percentage
| Sr. No. | Factors | Open sun drying | Polycarbonate dome dryer | Metal dome dryer | Solar flat dryer |
| 1 | Sawdust (in gm) | 2000 | 2000 | 2000 | 2000 |
| 2 | Water (in gm) | 2000 | 2000 | 2000 | 2000 |
| 3 | Initial temperature (in °c) | 30 | 33 | 30 | 33 |
| 4 | After 3 hr temperature (in °c) | 40 | 64 | 54 | 61 |
| 5 | Final temperature (in °c) | 35 | 39 | 36 | 39 |
| 6 | Duration (in hr) | 6 | 6 | 6 | 6 |
| 7 | Water remained (in gm) | 360 | 201 | 342 | 380 |
| 8 | Water evaporated (in gm) | 1640 | 1799 | 1658 | 1620 |
| 9 | Drying percentage | 82% | 89.9% | 82.9% | 81% |
Calculation:
1) Polycarbonate dome dryer
We know water evaporate=1799gm
Drying percentage= total water evaporated ÷ total water × 100
=1799÷2000×100
=89.95%
2) Metal dome dryer
We know water evaporate=1658gm
Drying percentage= total water evaporated ÷ total water × 100
=1658÷2000×100
=82.9%
3) Solar flat dryer
We know water evaporate=1620gm
Drying percentage= total water evaporated ÷ total water × 100
=1620÷2000×100
=81%
Date: 20/5/2022
- A boy from DBRT had dried beet in a dryer for his project, from this we noticed that the color of the beet in a flat dryer fades more than in a dome dryers.
- We got a response from the people who dried the onion and ginger that there was a strong smell in the dome dryer. Similarly, the smell of onion and ginger which was dried in a flat dryer is reduced.
Date: 26/5/20222
I connected the fan to the metal dome dryer. And mixed 2 kg of sawdust in 2 kg of water then fill trays. Put the tray in metal dome dryer to dry for 6 hours. After 6 hours weighed all the trays and calculate drying percentage. We know that 1290 gm of water evaporates out of 2000 gm of water.
Drying percentage = Evaporated water / total water * 100
= 1290 / 2000 * 100
= 64.5%.
Outcomes: After installing fan on the top of dryer, the drying percentage was 64.5%. We noticed that drying percentage of dryer with fan was lower than the drying percentage of dryer without fan.
Table no. 2 Difference between three dryers
| Sr. No. | Factors | Polycarbonate dome dryer | Metal dome dryer | Solar flat dryer |
| 1 | Cost (in Rs.) | 50234 | 43894 | 8491 |
| 2 | Cost per capacity ((in Rs.) | 7176 | 6270 | 1698 |
| 3 | *Capacity (as per substrate) | 7kg of sawdust | 7kg of sawdust | 5kg of sawdust |
| 4 | Temperature | 64°c | 64°c 54°c | 61°c |
| 5 | Drying percentage | 90% | 83% | 81% |
| 6 | Efficiency | 32% | 32% | 43% |
| 7 | Fragrance | Strong | Strong | Pleasant |
| 8 | Maintenance | Difficult | Difficult | Easy |
| 9 | Color | Dark | Dark | Dull |
Result:
- Out of the three dryers, the polycarbonate dome dryer has the highest drying percentage.
- Solar flat dryer is the most efficient out of the three dryer.
- Maintenance of dome dryers is difficult because it has too many components.
Conclusion:
- The capacity of the dryer varies with its substrate.
- If you dried the food in a dryer than in open sun drying, it will dry in less time. At the same time, its smell and color remain the same.
- As per my result and observation, I recommend to a small venture they have to take solar flat dryer.
- If a community wants to retain their color then he goes a polycarbonate dome dryer.
