Bringing The Sun Closer To Home
Team members:ANIRUDH ROY
UTKARSH SINGHAL
SRIJAN KUMAR
NANDINI AGNIHOTRI
Delhi Public School Ghaziabad
Bringing the Sun closer to home
Converting existing inverter into
Solar Power Inverter
Bringing the Sun closer to home
• Aims and objectives of study
• To study the feasibility of converting existing
household inverter into solar powered
inverter.
• Hypothesis
• Household inverters can successfully be
transformed into a solar powered inverter.
Bringing the Sun closer to home
• Need Statement
• 5-6 hours of power backup in cost effective
manner especially during summers when
power cut is more than 8-12 hours a day.
The grid supply is generally not available from 30%50% of time in towns like Ghaziabad during peak
summer.
Methodology
• Group A did extensive research and worked on
•
•
The report
•
Home Power Back Up Case study
•
Log book
Group B worked on
•
Charts and posters
•
Model
•
Validation of recommendations of Group A
RESEARCH FINDINGS
• Home Power Back Up – A Case study
• We have an inverter with a backup capacity of 800 VA and a battery of
150 AH. It can run 1 fan, 7 CFLs, a 54 cm T.V and 1 computer at the
same time for 2 hours (approx.).
• We calculated the duration of backup by the following formulae:
Battery AH x Battery voltage / inverter capacity
• (in our case) 150AHx12V/800VA =2.25 hours (at full load)
• RUNNING OUR INVERTER
•
at full load = 2.25 hours
•
at half load= 4.5 hours
We do not get 4.5hrs of back up due to power cuts of 8-12 hrs.
during peak summer even on 50% load.
RESEARCH FINDINGS Contd…
• Compatibility of solar panels
system with existing inverters
– Our study revealed that solar panel
system can be connected to the
existing inverter with a simple
charge controller.
– Various vendors have the solution
but none of them are marketing it
aggressively. Instead they suggest
double battery inverters designed by
them.
RESEARCH FINDINGS Contd…
• COSTING
We contacted a few vendors and got few the quotes. The specification:
–
–
–
–
–
–
–
–
4 x 80 watt panel= 320 watt
Panel voltage= 12 V
Current produced= 26.67 Amps
Efficiency= 90%
Net current produced= 26.67*90%=24 amps
Battery Capacity= 150 AH
Time required for charging = Battery capacity/net current produced
= 150/24 or 6.25 hrs.
We are assuming that the whole installation will cost –Rs35,000/- all
inclusive taking the lowest offer of Rs 30,000/- based on the quotes
received
RESEARCH FINDINGS Contd…
• COST BENEFIT ANALYSIS
Since we are not getting 2.25 hrs. back up during the peak summer and
investing in 7.5 kVA Diesel Generator set is very expensive so we
compared the existing Inverter with 320 watt solar panel connection vs.
1400 VA Inverter with 2x150 AH battery system (known as double battery
inverter)
• In proposed case :300AHx12V/1400VA =2.6 hrs. (at full load)
• Running Proposed Inverter
–
–
At full load = 2.6 hours
At half load= 5.2 hours ( Our desired requirement of 5 hrs)
• The comparison was done for:
• Option 1: 800 VA inverter with 150 AH Single battery and 32O KW Solar Panel
VS
• Option 2: 1400 VA inverter with 2x 150 AH battery
For simplicity of understanding only one time capital cost and replacement cost of battery and
inverter has been considered. Power consumption, inflation, depreciation has been ignored in the
calculation. The results based on analysis exhibited in Table 1 are:
Comparison of Single Battery Inverter with Solar Panel VS Double Battery 1400 VA Inverter
Particulars
Inverter cost
Battery cost
Solar Panel and controller cost
Initial Capital cost
Option 1
800 VA Inverter with 150 AH battery
320 watt solar panel with charge controller
Nos
Amount
Total
Existing
4500
0
Existing
9000
0
1
35,000
35000
35000
Assumptions
Inverter life span
Battery life span
Solar panel Life span
Recurring cost for 12 years
Year
Option1
Year 0
35000
Year 1
0
Year 2
0
Year 3
9000
Capex+Opex (Rs)
44000
Year 4
0
Year 5
0
Year 6
9000
Capex+Opex (Rs)
53000
Year 7
0
Year 8
0
Year 9
13500
Capex+Opex (Rs)
66500
Year 10
0
Year 11
0
Year 12
13500
Capex+Opex (Rs)
80000
Capex= Capital Expenditure
Opex= Operating expenses
8 years
2 Years
20 Years
Option 2
23500
0
0
18000
41500
0
0
18000
59500
0
0
23500
83000
0
0
23500
106500
Battery Only
Battery Only
(Inverter plus battery)
Battery Only
Option 2
14000 VA inverter with 2 nos of 150 AH battery
No solar panel
Nos
Amount
Total
1
5500
5500
2
9000
18000
0
0
0
23500
Cost benefit Analysis
Table 1
RESEARCH FINDINGS Contd…
• The comparison (Table 1) reveals that Initial Capital cost of
Option 1 is more than Option 2. That’s one of the reason
that people go for Option 2.
• On analyzing the life cycle it is clear that Option 2 Capital
expenditure +Operating expenditure increase by 76% in 3
years while in option 1 it increases by only 25%.
• Deeper probing reveals that Option 2 total expenditure
exceeds Option 1 in Year 6 i.e. Option 1 becomes profitable
after Year 6 and there on.
• Our existing inverter cost and battery cost is not considered
in the current comparison. If we consider complete fresh
purchase of all the items in case of Option 1, than Option 1
will be profitable after 9 years and will cost whopping Rs
48,500/-.
Conclusion
•
•
•
Since the initial capital investment is
high, people tend to purchase either
double battery inverter or 7.5 KVA DG
set which is not green technology and
requires high operating cost of diesel
which is on rise.
Since the gestation of recovery period
is high i.e.- 6 years, people tend to go
for Option 2. Option 1 will become
more attractive as the solar panel
costs falls, as it is happening in case
of mobile handsets. Already the cost
of solar panels have come down from
Rs 150/watt to Rs 75/watt.
Government provides incentives for
opting for solar panels, like being
done for large solar power projects.
However there are strong followers of Green
Power who adopt solar power inverters even
against all odds like Mr. Jose George, a resident
of Sector 22 Dwarka, New Delhi whose interview
was published in Deccan Herald. According to
him:
“I got a One KW solar panel installed at my
place five years ago. Initially, it did burn a hole
in my pocket and I was also skeptical if it
would bring me any benefit but in the long run,
it has. All the light-load appliances in my
three-bedroom flat are run on the power
generated from the solar panel; the heavy-load
appliances like AC, fridge and water motor are
run on the normal electricity supply, and my
electricity bill has come down from Rs 5000
per month to just Rs 1000. Besides, I
recovered the whole amount I had invested in
the solar panel in three years.”
Future Plans
• Further study of our option and look for alternate
solar panel technologies which increase our
existing battery back up in shortest possible time or
at lesser upfront cost.
• Demo project at our school for Option 1.
• Writing proposals to the Government for providing
incentives to consumers opting for solar panels
less than 1 KW e.g in case of switching to LPG
from Kerosene stoves.
Thank You