We are now running the system for exactly one year to the day.
A quick look at the data accumulated, (I keep a detailed log of
all important parameters like DC power produced, AC power
generated from that DC power, AC power consumed by the load,
AC power returned to the grid, power used to charge the batteries
etc).
So far we generated 9 MWh of Solar (DC). With a conversion efficiency
of about 80% that gave us 7.2 MWh of usable 220VAC power.
Keeping in mind that we started off with only 16 250W panels,
then added 5 more and 3 more only a few months ago plus
an upgrade to the inverter which lasted 3 weeks for which we had
to use the grid, we have used only 1.2MWh of grid power
the whole year.
Which means we are now totally self sufficient since adding the
last 3 panels. As I said in my last post I am waiting for the new
inverter which has 2 100 Amp MPPT's which will overcome
our current bottleneck of a 80 A MPPT. During the peak hours
of sunshine we are usually in Charge Limit and loosing out on quite
a few kWh per day.
All in all I am very happy with the performance of the system.
Money well spent, but most of all, the peace of mind that brings.
Not to forget the satisfaction of a job well done.
The cost of electricity has gone up something like 120% in the last
few years and is being increased by 16% annually over the next
5 years we have been informed. That will more than double the
price of electricity in that period. And I'm sure all the other
charges associated with our municipal account will also increase
at similar rates.
Somebody has to pay for our 30 million unemployable countrymen.
There are about 5 million registered taxpayers in the country
but we have 14 million receiving some government grant or other.
And just this week it was decided by our illustrious leaders that
they intend to give a job seekers grant to an other few millions.
This is because the Education System has been completely destroyed.
To pass Matric, that is the final exam after 12 years of schooling, a pass rate
of between 30 and 40 % is required. My dog can do better than this.
This is despite the fact that most students do not take Mathematics as a
subject at all because the majority would fail the year.
So the Education Authority introduced a extremely watered down subject
called Mathematical Literacy. That is basically so they can at least understand
a Bank Statement when they see one. Not that they will ever get one themselves
as this would require getting a job first.
But this is the least of our worries. What is far more disturbing is the fact that our
Universities are producing Graduates which have absolutely no clue whatsoever
of the subject they studied for 4 years.
I had the rare pleasure of evaluating two of them. From one of the top Engineering
Universities, not the bottom of the heap.
I have never seen such lack of understanding. And by this I mean of the Basics.
I knew more before I began my studies then these two after four years.
And they are both doing their Masters at the moment. Hoo Boy.
How the hell can a reputable University even consider conferring a Degree if it was not
for political interference from the top.
When I politely inquired about the sorry state of their competency I was equally politely
informed that they were told by their professors that in this country we only do
maintenance so electronic design knowledge will never be required.
And I was of the opinion that was the reason one went to university in the first place.
Evidently I was wrong.
Tuesday, December 25, 2012
Sunday, December 2, 2012
Effect of adding the last 3 panels
Since we added the last 3 250W PV panels a few months ago we now
are producing up to 40kWh a day on clear sunny days which are the norm
in Johannesburg. We must have at least 300 of such days per year.
One of the very best climates on the planet. Beautiful days and cool nights.
But even on cloudy days we produce up to 30kWh. The sunlight is more
diffused then and the ambient temperature is lower which is a major factor when it comes to the efficiency with which the panels convert sunlight into electricity.
The limiting factor as this point in time is the MPPT (Maximum Power
Point Tracker) which limits at 80 Amperes. The panels can supply more.
I have ordered a new 8kW Grid tied inverter with two 100 A MPPT's
build in but there were some delays with the design of the MPPT's I was told. Then the bottleneck of the 80A limit is gone and we should be
able to harvest the maximum power.
Since I am running the entire property on solar, including the pool pump,
2 air cons, a electronic design lab with a staff of 8, half a dozen computers
and last but not least a 3 kW kettle which is probably most heavily used item, working overtime daily I could use the extra power.
A calculation showed that we could expect 50kWh a day.
Looking at some data which gives the level of insolation at our latitudes
it says we are receiving over 6kWh per square meter. If you multiply this
with the area of a panel and its efficiency then one comes very close to the
250W the panel can deliver. This is a very effective way to calculate the
number of panels required for a particular installation. I will do some
measurements to see how much a panel can actually deliver on a perfect
day. I am sure it will be more then 250 Watts. The 250 Watt figure is
the factory spec when the panel is tested in the factory with the industry
standard 1000W/m2 light source. Not sure what is the spectral distribution of that light source, (does it approximate sun light?)
since a PV panel is sensitive to spectral variations.
are producing up to 40kWh a day on clear sunny days which are the norm
in Johannesburg. We must have at least 300 of such days per year.
One of the very best climates on the planet. Beautiful days and cool nights.
But even on cloudy days we produce up to 30kWh. The sunlight is more
diffused then and the ambient temperature is lower which is a major factor when it comes to the efficiency with which the panels convert sunlight into electricity.
The limiting factor as this point in time is the MPPT (Maximum Power
Point Tracker) which limits at 80 Amperes. The panels can supply more.
I have ordered a new 8kW Grid tied inverter with two 100 A MPPT's
build in but there were some delays with the design of the MPPT's I was told. Then the bottleneck of the 80A limit is gone and we should be
able to harvest the maximum power.
Since I am running the entire property on solar, including the pool pump,
2 air cons, a electronic design lab with a staff of 8, half a dozen computers
and last but not least a 3 kW kettle which is probably most heavily used item, working overtime daily I could use the extra power.
A calculation showed that we could expect 50kWh a day.
Looking at some data which gives the level of insolation at our latitudes
it says we are receiving over 6kWh per square meter. If you multiply this
with the area of a panel and its efficiency then one comes very close to the
250W the panel can deliver. This is a very effective way to calculate the
number of panels required for a particular installation. I will do some
measurements to see how much a panel can actually deliver on a perfect
day. I am sure it will be more then 250 Watts. The 250 Watt figure is
the factory spec when the panel is tested in the factory with the industry
standard 1000W/m2 light source. Not sure what is the spectral distribution of that light source, (does it approximate sun light?)
since a PV panel is sensitive to spectral variations.
Thursday, August 9, 2012
Crazy 5000km Helicopter Flight
Mark, that is my son, has been on a few tours to the Sudan late last year and once or twice this year.
He is a commercial Chopper Pilot and is flying Long Rangers as well as Bell HU1's amongst other
types like Bell 407's Robinson R22, R44 etc.
The Helicopters and crew's are supplied by South African Aviation Companies to virtually all African
Countries for a variety of tasks.
In the Sudan, which has almost no roads and the few it has have been beneficiated with land mines, the only
way to go anywhere is by helicopter.
He's job was to take workers and supplies to the oil fields and back amongst other things.
Then the North and South had their much publicized split which culminated in the obligatory
exchange of gunfire and bombs. True to form, nothing new.
So everybody had to get out from there. There was some advance warning so everybody
got out safely. They did not want to leave the choppers behind so someone had to fly them
back to South Africa. Since Mark at that time was on tour he took the Long Ranger, fitted the
ferry tanks and set of for Kampala (Uganda) to have some new Rotor Blades fitted. That took a week.
As he was the only pilot (he had a passenger, one of the fixed wing engineers who also had to get
out) it was up to him to get them and the chopper back safely.
I am going to upload a lot of the flight documentation (flight plans, military clearances etc.)
The first leg was to go across Lake Victoria in a single engine chopper
(a 2 hour flight across water with no floats or life jackets)
into Tanzania, across the well known Serengeti to Mount Kilimanjaro where they spent the night
at the hotel.
A few years earlier one of his class mates was the co-pilot of a plane that crashed into the mountain
a few feet below the summit. As it involved a number of wealthy international tourists the crash made
headlines around the world.
Then further on to Dar Es Salam and then due south along the coastline into Mocambique
re-fueling a number of times along the way. Finally across the South African border at the Kruger Park.
Then the last leg from Kruger Park (Nelspruit Airport) to Lanseria Airport in Johannesburg.
The whole trip lasted 9 days. The flying part alone was 5 days (40 hours). 5000 km exactly.
Lots of red tape on the way as usual when flying in Africa.
Since most choppers do not have an auto pilot all of the flying is done by the pilot. And a chopper
needs to be hand flown from take off to landing. One can lock the throttle, that helps a bit but there is
no lapse of concentration allowed.
As I said I will upload a lot of the documentation which he accumulated. Have already scanned in
most of it. Not many people have the opportunity to go on such an adventure. Flying in Africa is still
a hazardous business due to the sheer size of the continent alone. It is also a very beautiful continent, not
yet dragged into the 20th century, let alone the 21st.
At the moment Mark is in Angola on a 3 month contract. They took 6 choppers up to Luanda
(13 hours flying time). Last time I had an e-mail from him he was taking some ballot boxes
and election officials around.
He is a commercial Chopper Pilot and is flying Long Rangers as well as Bell HU1's amongst other
types like Bell 407's Robinson R22, R44 etc.
The Helicopters and crew's are supplied by South African Aviation Companies to virtually all African
Countries for a variety of tasks.
In the Sudan, which has almost no roads and the few it has have been beneficiated with land mines, the only
way to go anywhere is by helicopter.
He's job was to take workers and supplies to the oil fields and back amongst other things.
Then the North and South had their much publicized split which culminated in the obligatory
exchange of gunfire and bombs. True to form, nothing new.
So everybody had to get out from there. There was some advance warning so everybody
got out safely. They did not want to leave the choppers behind so someone had to fly them
back to South Africa. Since Mark at that time was on tour he took the Long Ranger, fitted the
ferry tanks and set of for Kampala (Uganda) to have some new Rotor Blades fitted. That took a week.
As he was the only pilot (he had a passenger, one of the fixed wing engineers who also had to get
out) it was up to him to get them and the chopper back safely.
I am going to upload a lot of the flight documentation (flight plans, military clearances etc.)
The first leg was to go across Lake Victoria in a single engine chopper
(a 2 hour flight across water with no floats or life jackets)
into Tanzania, across the well known Serengeti to Mount Kilimanjaro where they spent the night
at the hotel.
A few years earlier one of his class mates was the co-pilot of a plane that crashed into the mountain
a few feet below the summit. As it involved a number of wealthy international tourists the crash made
headlines around the world.
Then further on to Dar Es Salam and then due south along the coastline into Mocambique
re-fueling a number of times along the way. Finally across the South African border at the Kruger Park.
Then the last leg from Kruger Park (Nelspruit Airport) to Lanseria Airport in Johannesburg.
The whole trip lasted 9 days. The flying part alone was 5 days (40 hours). 5000 km exactly.
Lots of red tape on the way as usual when flying in Africa.
Since most choppers do not have an auto pilot all of the flying is done by the pilot. And a chopper
needs to be hand flown from take off to landing. One can lock the throttle, that helps a bit but there is
no lapse of concentration allowed.
As I said I will upload a lot of the documentation which he accumulated. Have already scanned in
most of it. Not many people have the opportunity to go on such an adventure. Flying in Africa is still
a hazardous business due to the sheer size of the continent alone. It is also a very beautiful continent, not
yet dragged into the 20th century, let alone the 21st.
At the moment Mark is in Angola on a 3 month contract. They took 6 choppers up to Luanda
(13 hours flying time). Last time I had an e-mail from him he was taking some ballot boxes
and election officials around.
More panels and a new inverter
Had a spot on the roof which was begging for some Solar Panels.
Fitted 3 more 250 Watt mono-chrystaline. Now we are full house
so to speak. Total installed Solar Capacity is now 6 kW.
At the moment we are at the end of winter so we are 20 to 30%
down on what is available in summer. Saw a maximum of
6000 Watts being generated 3 days ago. For the past two days
we had the most extreme weather ever experienced in South Africa.
We had snowfall in all 9 provinces with many roads closed and
icy conditions. No sun in sight. Still managed to get a total of 30 kWh
for these two days. Almost breaking even with consumption.
Today the weather was back to normal, beautiful blue skys with
no cloud in sight but still a bit on the cool side. Managed 35kWh.
Also ordered a new model of the Grid tied Inverter.
Also 8kVA but with 2 100 Amp MPPT (Maximum Power Trackers).
Will split the 24 Panels into 2 groups of 2x12 and feed one each to
the 2 MPPT. So that will give me some redundancy.
Will keep the old inverter as a back-up. Its only 2 years old but
it was one of the first of the 8kVA models produced by the
manufacturer and it had a problem after two months of operations
which necessitated a major repair. Been working fine since.
But you never know. So the new one is coming this week.
It's an upgraded version which carries a 5 year warranty.
Not exactly cheap at almost R70,000 ($9,000) but as I said
before, my Porsche deserves a warm garage.
An other interesting little episode happened 2 months ago when I
checked the water levels in my 1660Ah battery bank.
Was getting a bit low so I shopped around for some distilled water.
Not as easy as you would expect. Bought 5 liters from one of my
suppliers I also use for my business. He sourced some from some
shady supplier. I phoned them asking for a spec sheet for the
distilled water they are selling for as much money as I would pay
for a bottle of Whisky. Got a spec sheet but it was very cagey.
So I also bought a 25 liter container from the manufacturer of the
batteries. Should have thought of it earlier, but they are 30km
away so the first option was more convenient.
So I filled 3 little bottles with the 2 distilled waters I bought and
one more with some tap water from my tap in the kitchen.
(As a control).
Then took them to a approved Water Laboratory in Pretoria
and had them analyzed.
No surprises there. The water from the battery manufacturer
was proper distilled water. The other two were ordinary tap
water. The one from my own tap and the other that very
expensive one. These two were virtually identical!
So my supplier then demanded from the supplier of the
expensive tap water that they pay for the water analysis.
This they did to my surprise considering the cost of the analysis
was R2200 ($275). Hopefully this will teach them a lesson.
If I would have used that water to top up the batteries and they
would become contaminated with all the impurities and develop
a much reduced capacity my warranty would be invalid.
Since the batteries are the most expensive component of the
system costing R96,000 ($12,000) it pays to be careful.
Fitted 3 more 250 Watt mono-chrystaline. Now we are full house
so to speak. Total installed Solar Capacity is now 6 kW.
At the moment we are at the end of winter so we are 20 to 30%
down on what is available in summer. Saw a maximum of
6000 Watts being generated 3 days ago. For the past two days
we had the most extreme weather ever experienced in South Africa.
We had snowfall in all 9 provinces with many roads closed and
icy conditions. No sun in sight. Still managed to get a total of 30 kWh
for these two days. Almost breaking even with consumption.
Today the weather was back to normal, beautiful blue skys with
no cloud in sight but still a bit on the cool side. Managed 35kWh.
Also ordered a new model of the Grid tied Inverter.
Also 8kVA but with 2 100 Amp MPPT (Maximum Power Trackers).
Will split the 24 Panels into 2 groups of 2x12 and feed one each to
the 2 MPPT. So that will give me some redundancy.
Will keep the old inverter as a back-up. Its only 2 years old but
it was one of the first of the 8kVA models produced by the
manufacturer and it had a problem after two months of operations
which necessitated a major repair. Been working fine since.
But you never know. So the new one is coming this week.
It's an upgraded version which carries a 5 year warranty.
Not exactly cheap at almost R70,000 ($9,000) but as I said
before, my Porsche deserves a warm garage.
An other interesting little episode happened 2 months ago when I
checked the water levels in my 1660Ah battery bank.
Was getting a bit low so I shopped around for some distilled water.
Not as easy as you would expect. Bought 5 liters from one of my
suppliers I also use for my business. He sourced some from some
shady supplier. I phoned them asking for a spec sheet for the
distilled water they are selling for as much money as I would pay
for a bottle of Whisky. Got a spec sheet but it was very cagey.
So I also bought a 25 liter container from the manufacturer of the
batteries. Should have thought of it earlier, but they are 30km
away so the first option was more convenient.
So I filled 3 little bottles with the 2 distilled waters I bought and
one more with some tap water from my tap in the kitchen.
(As a control).
Then took them to a approved Water Laboratory in Pretoria
and had them analyzed.
No surprises there. The water from the battery manufacturer
was proper distilled water. The other two were ordinary tap
water. The one from my own tap and the other that very
expensive one. These two were virtually identical!
So my supplier then demanded from the supplier of the
expensive tap water that they pay for the water analysis.
This they did to my surprise considering the cost of the analysis
was R2200 ($275). Hopefully this will teach them a lesson.
If I would have used that water to top up the batteries and they
would become contaminated with all the impurities and develop
a much reduced capacity my warranty would be invalid.
Since the batteries are the most expensive component of the
system costing R96,000 ($12,000) it pays to be careful.
Friday, April 27, 2012
I installed this medium size Solar System in December 2011. Due to the continual Black-outs as well as
Load-Shedding because of the incompetence of everybody involved in the provision of electricity I decided
to become independent from the Grid. The system is producing 50% more KWh than we are using on average. We did an upgrade in late March where we added 5 more 250 Watt panels and reconfigured
all of the panels as 3x7.
(Three 250Watt panels in series and 7 of these in parallel.) This modification proved most beneficial
as the MPPT (Multi point Power Tracker) now has the required headroom to adjust the maximum power point (that is the point on the solar panel operating characteristic) where the panels produce the highest
power for the prevailing weather conditions.
Since the upgrade (24 March 2012) we produced approx. 900 kWh of solar energy. 27kWh per day average. Usage was approx. 700 kWh. So despite a few days with relatively low insolation (that is the term used to describe how much sunlight is reaching the earths surface) we had an excess of 200kWh which was returned to the grid.
Only yesterday we had a cold and totally overcast day and still we managed 9kWh, 40% of the demand.
The systems performance can be monitored either On-line via a G3 link or connecting one of our Laptops
to the inverter and having access to all data as well as being able to set all of the operating modes.
All relevant performance data is stored on a memory card and can be accessed and plotted with the
software package provided. When using the SCADA functionality one can monitor the entire system
with all its connected sources and loads. Very much like a real power station.
I will post some graphs in the near future. Of course this does not come cheap. But my Porsche deserves
a warm garage.
Load-Shedding because of the incompetence of everybody involved in the provision of electricity I decided
to become independent from the Grid. The system is producing 50% more KWh than we are using on average. We did an upgrade in late March where we added 5 more 250 Watt panels and reconfigured
all of the panels as 3x7.
(Three 250Watt panels in series and 7 of these in parallel.) This modification proved most beneficial
as the MPPT (Multi point Power Tracker) now has the required headroom to adjust the maximum power point (that is the point on the solar panel operating characteristic) where the panels produce the highest
power for the prevailing weather conditions.
Since the upgrade (24 March 2012) we produced approx. 900 kWh of solar energy. 27kWh per day average. Usage was approx. 700 kWh. So despite a few days with relatively low insolation (that is the term used to describe how much sunlight is reaching the earths surface) we had an excess of 200kWh which was returned to the grid.
Only yesterday we had a cold and totally overcast day and still we managed 9kWh, 40% of the demand.
The systems performance can be monitored either On-line via a G3 link or connecting one of our Laptops
to the inverter and having access to all data as well as being able to set all of the operating modes.
All relevant performance data is stored on a memory card and can be accessed and plotted with the
software package provided. When using the SCADA functionality one can monitor the entire system
with all its connected sources and loads. Very much like a real power station.
I will post some graphs in the near future. Of course this does not come cheap. But my Porsche deserves
a warm garage.
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Vorna Valley Johannesburg
I live right in the middle of the picture
My Life Philosophy
