Solar Panel Installation

Cocoon

I am looking to install a vacuum tube solar system with 300L tank and possibly a heat dump, as i'd like to maybe over do it on the vacuum tubes for the autumn and spring months and not have to worry about overheating in the summer.

It seems to be a mine field of suppliers and fitters out there and i don't want to be stung, i know fitters names can't be named here but i'd appreciate if somebody could point me in the right direction by PM. I'm located on the northside of Dublin. Hope someone can help me out. Thanks

Open A

I'm looking for the same for a client. If you get any good recommendations, please PM. I'll let you know if I find anything..

Cocoon

Open A wrote: »

I'm looking for the same for a client. If you get any good recommendations, please PM. I'll let you know if I find anything..

I haven't had any recommendations yet and don't know where to start looking, maybe I'll just get some quotes from the Kingspan list of installers, and even at that I'm not sure if that the best type of panel to go with. I've read through lots of threads here trying to educate myself a bit so to know what I need as I'd like to get this installation right first time. I hope someone points me in the right direction. I'll send you a PM should I have any luck.

tphase

you could try here for recommendations

championc

PM's sent

I can recommend Kingspan because the tubes have nozzles which release excess heat rather than needing a solar dump.

Regarding sizing for a 300L system, you should look for AT LEAST 50 tubes. To maximize the gains, I recently had my own system modified by my installer to add top loading to the system. I originally got a buffer tank with two coils and the system was linked to the bottom coil. Now it's linked to both colis and can top up the top half of the buffer tank first before heating the bottom which, only having to heat half the water should give good results in Autumn and Spring and even a return from Winter sunshine.

Cocoon

championc wrote: »

PM's sent

I can recommend Kingspan because the tubes have nozzles which release excess heat rather than needing a solar dump.

Regarding sizing for a 300L system, you should look for AT LEAST 50 tubes. To maximize the gains, I recently had my own system modified by my installer to add top loading to the system. I originally got a buffer tank with two coils and the system was linked to the bottom coil. Now it's linked to both colis and can top up the top half of the buffer tank first before heating the bottom which, only having to heat half the water should give good results in Autumn and Spring and even a return from Winter sunshine.

Thanks for the PM, I'm going to get a few quotes on different systems. I like the sound of the Kingspan system and they must believe in there heat release technology if they are offering a 20 year guarantee on tubes, assuming the spring release valve is in the tube sooner than the manifold.

It will be also interesting to see how many tubes that will be recommended for 300L. I really hope I get this right first time and make the right decisions.

championc

I have 30 tubes with 180 Liters. I feel this is well sized especially with out ****ty summer this year. You would need complete sunshine about 3-4 days in a row for the system to reach the Max temperature.

engineermike

Hi,
Most systems that are as efficient as Kingspan HP / DF systems & a no. of others on the market are matched as follows : 200L tank = 20 tubes, 300 L tank = 30 tubes. 500 L tank = 50 tubes and so on.
Kingspan will and most reputable installers / systems - still recommend a heat dump is tied in if you know in advance that your home / building will be unoccupied for more that 2 weeks per year. The 'Snap disk' temp. limit device that you've mentioned is a feature to prevent the system from damaging itself or degrading the antifreeze in the energy loop by over temp. - but you wouldn't intentionally install a system knowing in advance that the tank will reach temp. and the energy would not get used - causing damage over time.
It would be a bit like installing a PRD - knowing full we'll it would blow off often.
Mike F

maradonas

If you go on holiday isnt there a holiday mode to bring the temperature down at night time so it saves the life of the tubes instead of having a heat dump?

Outkast_IRE

maradonas wrote: »

If you go on holiday isnt there a holiday mode to bring the temperature down at night time so it saves the life of the tubes instead of having a heat dump?

As far as i know its not acceptable to use holiday mode instead of a heat dump, the holiday mode only works to try and cool the cylinder at night i dont think it would be able to cool the cylinder down enough to replace a heat dump. If this is the way your system is done then i wouldnt be 100% happy with it.

engineermike

Outkast_IRE wrote: »

As far as i know its not acceptable to use holiday mode instead of a heat dump, the holiday mode only works to try and cool the cylinder at night i dont think it would be able to cool the cylinder down enough to replace a heat dump. If this is the way your system is done then i wouldnt be 100% happy with it.

Hi -
The Holiday dump is a differential - controlled by the electronic controller in most systems, this can only call up the pump on the energy loop to try and disperse the energy due to non use, but a primary call for the pump is overtemp. - therefore your energy loop (anti freeze) or tube is suffering abnormal wear and tear.
Its hard to think of too much sun / light in Ireland ( :eek:) but it happens, and over time components of a system will deteriorate - good planing is or estimated use / times / non usage times - periods help to design a system that both meets the needs of the household and doesn't suffer abnormal wear.
The sun is an uncontrollable energy source - there will be days when it over exceeds your requirement.
Mike F

quentingargan

Another problem with holiday mode is that it only cools the bottom of the cylinder - the area up to the top of the solar coil. Usually a well sized system is capable of reheating this again quite quickly, meaning that the system will go into stagnation each day while you are on holiday.

championc

engineermike wrote: »

Hi,
Most systems that are as efficient as Kingspan HP / DF systems & a no. of others on the market are matched as follows : 200L tank = 20 tubes, 300 L tank = 30 tubes. 500 L tank = 50 tubes and so on.

I cannot agree with your sizings. For me, 30 for 300L is too small and you'd struggle to get your complete water requirements met during the summer - and forget about any meaningful returns in Spring and Autumn. You'd be relying on blue skies from dawn to dusk.

My 30 tubes connected to a 180L store can increase my water temperature by just over 30 degrees in a single day June fully sunny day when the store temp is beginning around the 20 or 30 deg level. The higher your store temp, the more difficult it gets to increase it's temperature per degree. Therefore, if you have 30 tubes connected to a 300L store, you can get an idea now as to how much you will reply on blue skies day after day.

The whole idea of these systems is that you should not need to use any supplemental means (electricity / gas / oil) for as long as possible over the Spring to Autumn calendar

sas

championc wrote: »

I cannot agree with your sizings. For me, 30 for 300L is too small and you'd struggle to get your complete water requirements met during the summer - and forget about any meaningful returns in Spring and Autumn. You'd be relying on blue skies from dawn to dusk.

I have 90 tubes feeding a 1000 litre tank. We moved on May 4th. We don't have an immersion. We had oil installed in middle of July. The oil was run for 20mins 1 night to test it. It hasn't been used since.

We haven't run out of water since May 4th. Even when we had 3 days in a row where due to the appalling rain we had little or no solar gain. We came close on 2 occasions but the weather improved and we got by. It was after these 2 close calls that I pushed ahead with the oil. We haven't needed it since we installed it.

championc wrote: »

My 30 tubes connected to a 180L store can increase my water temperature by just over 30 degrees in a single day June fully sunny day when the store temp is beginning around the 20 or 30 deg level.

My 90 tubes in 1000 litre tank did the same in April before we moved in and again in May during the week of sunny weather. My system stagnates when the highest stat in the tank hits 70 degress, that's about 3/4 of the way up the tank in my case. On the occasion where this happened the bottom of the tank was 60 degrees.

championc wrote: »

The higher your store temp, the more difficult it gets to increase it's temperature per degree. Therefore, if you have 30 tubes connected to a 300L store, you can get an idea now as to how much you will reply on blue skies day after day.

Can you elaborate on this please because I don't understand your point at all?

championc wrote: »

The whole idea of these systems is that you should not need to use any supplemental means (electricity / gas / oil) for as long as possible over the Spring to Autumn calendar

My systems performance during this period is yet to be seen naturally enough. It will be interesting to see how it fairs.

quentingargan

If you have a small cylinder, and a lot of tubes, then the system will get back up to useful hot water quite quickly, even on an overcast day. But if you have 1000L cylinder, and 90 tubes or so, your water will fluctuate within a fairly high temperature range all the time.

If you were sizing a system for a larger cylinder, you wouldn't multiply out the number of tubes by the cylinder size. The tubes determine the heat production and the cylinder is the store.

But I think if I was using a 1000L cylinder, I would prefer to have a coil near the top that gave me about 200L of hot water first, before then switching over to warm up the rest of the cylinder. That would give the best of both worlds.

But a lot of houses put in 1000L buffers and large solar arrays to meet the renewables component of Part L of the building code. This may be inappropriate if there are two people living in a 300 sqM house. I would prefer to use either PVs or a combination of PV and solar thermal to meet Part L in this situation. I just can't see the payback staking on a 1000L 90 tube system unless you are using an awful lot of hot water.

sas

quentingargan wrote: »

If you have a small cylinder, and a lot of tubes, then the system will get back up to useful hot water quite quickly, even on an overcast day. But if you have 1000L cylinder, and 90 tubes or so, your water will fluctuate within a fairly high temperature range all the time.
.

I hope so.

quentingargan wrote: »

But I think if I was using a 1000L cylinder, I would prefer to have a coil near the top that gave me about 200L of hot water first, before then switching over to warm up the rest of the cylinder. That would give the best of both worlds.
.

I didn't know enough about solar when I made a call so I didn't know anything about this option.

quentingargan wrote: »

But a lot of houses put in 1000L buffers and large solar arrays to meet the renewables component of Part L of the building code. This may be inappropriate if there are two people living in a 300 sqM house. I would prefer to use either PVs or a combination of PV and solar thermal to meet Part L in this situation. I just can't see the payback staking on a 1000L 90 tube system unless you are using an awful lot of hot water.

I would also agree on the payback, I don't think I'll see payback if I live to be 100. This again is a live and learn, my timing was poor and at that point in time I was terrified of the chinese tubes. The tank in my case is a combined heating\DHW tank. The hotwater is extracted via heat exchanger. I'm happy with this single tank setup. The loops for the oil only target the top half of the tank. The connections for a timber boiler stove enter at the top and leave at the bottom i.e. boiler stove will target the full tank if I ever install it. The DHW heat exchanger takes hot water from the tank, extracts the heat and readds that water at the bottom.

championc

sas wrote: »

Can you elaborate on this please because I don't understand your point at all?

If I start with the buffer at 20 deg and get a full sunny day, I would expect the whole store to be over 50 deg by end of day. So a rise of over 30 deg.

However, if I start with the buffer at 50 deg, under the same conditions, the overall temperature my only rise to 65 or so.

So the higher the starting point, the less the incremental addin.

quentingargan wrote: »

But I think if I was using a 1000L cylinder, I would prefer to have a coil near the top that gave me about 200L of hot water first, before then switching over to warm up the rest of the cylinder. That would give the best of both worlds.

People should really seriously consider this option, even doing it to an already installed system - so long as your buffer has two coils and a controller that can support top loading. The idea is that the top section of the buffer will always be heated first so this should really maximize gains in Spring and Autumn and even for days of Winter sunshine.

Cocoon

I finally have a few quotes and the all come in around the same sort of money, but I'm now trying to decide which I'd be better with?

60 x good quality Chinese 58mm tubes feeding 300L

40 x thermomax hp-400 feeding 300L

both were quoted using a heat dump.

I'm also going to go for a controller that writes to a SD card to keep an eye on the results of the finished project.

So what should I go for?

championc

The Kingspan SC300 has an SDCard slot and can also send the data out via RS232. I'm hoping to link mine to a Raspberry Pi and post the data out to http://www.cosm.com (formerly Pachube)

BTW, The Kingspan Thermomax should NOT need a heatdump. I bet you didn't get that suggestion from the installer I PM'd to you.

As for systems, why not ask an installer for data from a Real Live system ? The one thing that impressed me about the Kingspan is that the heat gain seem pretty much the same at 10am or 4pm as it is for 1pm when the sun is directly overhead. Having data capture means that you can see (and prove) stuff like this.

Finally, I'd go with 50 tubes for 300L if you go Kingspan.

Cocoon

Thanks for the reply regarding the thermomax tubes as you have first hand experience with them, what I'd like to know is if the higher quality thermomax tubes would require less tubes to give the same result?

As far as a heat dump goes I still think the thermomax tubes need one especially if you over size the system. I don't think they would see 20 years if they are maxing out all the time. Then again it would be a good test for kingspans warranty.

The reason I didn't give your installer a call is there's a 10% discount with the ESB at the moment and out of curiosity I wanted to see what they would quote.

tails_naf

Cocoon wrote: »

. I don't think they would see 20 years if they are maxing out all the time.

Do you know what the failure mode is when they 'max out' ? Does the excess heat damage something in particular?

I had tubes on the roof for a few months that were not in use until recently, so I expect they were heating up every day, but had nothing at all to reduce the heat in them (as they were not connected to anything) - so were surely 'maxing out' in terms of temp at the roof.

Cocoon

tails_naf wrote: »

Do you know what the failure mode is when they 'max out' ? Does the excess heat damage something in particular?

I had tubes on the roof for a few months that were not in use until recently, so I expect they were heating up every day, but had nothing at all to reduce the heat in them (as they were not connected to anything) - so were surely 'maxing out' in terms of temp at the roof.

As far as I know with kingspan tubes they have a spring loaded device that disengages the tube from the manifold when the temp hits 90/95c, each tube has this spring loaded device.

How I see it is if this has to happen a lot during the summer months it may cause the mechanism to fail in the long term. Where as if even a small heat dump is installed, maybe the spring loaded mechanism in the tubes will only be needed on the odd occasion. The less moving parts the better, but as a fail safe worth having as to prevent the system going into stagnation and putting components under pressure.

tails_naf

Cocoon wrote: »

As far as I know with kingspan tubes they have a spring loaded device that disengages the tube from the manifold when the temp hits 90/95c, each tube has this spring loaded device.

How I see it is if this has to happen a lot during the summer months it may cause the mechanism to fail in the long term. Where as if even a small heat dump is installed, maybe the spring loaded mechanism in the tubes will only be needed on the odd occasion. The less moving parts the better, but as a fail safe worth having as to prevent the system going into stagnation and putting components under pressure.

I definitely don't have this feature in my tubes - they will just keep on heating whatever temp they hit. I wonder what the kingspan mechanism is trying to prevent - damage to the tubes themselves, or just preventing producing 'water' at > 90C

championc

It is a feature of the Kingspan system having the "spring loaded device that disengages the tube from the manifold when the temp hits 90/95c"

Have you ever see the size of a 300l system ? It's huge. Installers may lead you to believe that it's going to be boiling over day after day - well it won't be. Even if you don't use a drop of water, it would take about 4 days of brilliant sunshine to get up to 80+ deg C. I never once hit the top this year nor last and it only happened on one day in 2010. I have my max set to 85 deg C. I can tell you it is VERY difficult to raise the temperature above the 75 mark.

I started with the thoughts of supplementing my Central Heating - extracting excess heat from the store into the rads circuit. It's certainly not worth doing for the few times a bit of benefit could be gained.

As for the heat output, don't trust promises or heresay. Seek data - real data. I have posted graphs from my data in other posts but sadly, I've never seen anyone else post any. I challenged others to but nobody responded.

To anyone out there - Data is KING. You can prove or disprove anything with data. Particularly with solar, you can spot a faulty setup or component very easily.

And as for 10% off, why not contact an installer and bargain to match the 10% !!! I can certainly say that the guy I recommended is very knowledgable and, more to the point, has a system (and also a PV) on his own roof. You'll get some getting into the solar game just because it's an expanding business and they have plumbing experience.

tails_naf

Thanks championc - I agree 100% that data is king, and I have been very interested in looking at all of the data you have posted - it has been very helpful.

I just started a thread on 'Expected Solar Performance' as I believe I am seeing poor performance. I posted data from yesterday (manually graphed), and from that it says the collector temp never goes above 49C - and it was only heating at most 100L, with the pump starting/stopping a lot.

If you happen to have data from yesterday, that would be great.

I am looking into getting a data-logger added to the system, and motoring the pump start-times and more temperatures.

saibhne

I have had experience of three Kingspan HP systems installed which have all exceeded the 90 degree limit. Two systems were 40 tubes with 300L and I have seen one of these systems sitting at 145 degrees. The only sure option available was to install a heat dump to cater for the excess.

With Kingspan HP systems once you veer off their standard sizing of 30 tubes with 300L or 20 tubes with 200L you should definitely consider overheating as an issue.

championc

saibhne wrote: »

With Kingspan HP systems once you veer off their standard sizing of 30 tubes with 300L or 20 tubes with 200L you should definitely consider overheating as an issue.

I have 30 Tubes on 180L store. The only thing I would say is that because I have a combi boiler, I don't have anything else heating the water other than the Solar Tubes so if I use all of my hot water and we have no sunshine, I have 180L of 10 degree C water !!

saibhne

championc wrote: »

I have 30 Tubes on 180L store. The only thing I would say is that because I have a combi boiler, I don't have anything else heating the water other than the Solar Tubes so if I use all of my hot water and we have no sunshine, I have 180L of 10 degree C water !!

Hi Champion, I suppose the question is what happens when you don't use all your hot water and we have lots of sunshine.. (the stuff we used to get in summer..):)

S.

championc

saibhne wrote: »

Hi Champion, I suppose the question is what happens when you don't use all your hot water and we have lots of sunshine.. (the stuff we used to get in summer..):)

S.

Thankfully, the Thermomax tube valve will do it's thing. Yes, I know, I'm putting my trust in the system as it was designed.

tails_naf wrote: »

If you happen to have data from yesterday, that would be great.

engineermike

Hi,
Kingspan have quite a rigid site spec sheet / estimated usage / holiday weeks are all entered in to the site survey. They then specify the system and how it should be installed - heat dumps etc. etc.
And if you want the 20 year warranty you've got to have every box ticked as they specify.
There are a number of other systems / manu. that specify the same good practice when using there systems and installing.

mike f

quentingargan

engineermike wrote: »

Hi,
Kingspan have quite a rigid site spec sheet / estimated usage / holiday weeks are all entered in to the site survey. And if you want the 20 year warranty you've got to have every box ticked as they specify.

There is an assumption that the valve on top of the heatpipe is a panacea that can replace the heat dump in over-sized systems. This assumption is, perhaps, contradicted by the fact that the warranty is dependent on the system being sized appropriately.

I have always believed that solar thermal systems should be slightly over-sized - particularly on houses with good insulation - so you get maximum cover at the fringes of the season when the central heating is off. Those fringes have been with us for most of this summer alas....

You can only over-size a system if there is an appropriate heat dump to prevent stresses incurred from overheating. I would personally prefer to see a normal heat dump on all systems, regardless of whether there is a valve present to contain the heat within the heat pipe itself.

Cocoon

quentingargan wrote: »

There is an assumption that the valve on top of the heatpipe is a panacea that can replace the heat dump in over-sized systems. This assumption is, perhaps, contradicted by the fact that the warranty is dependent on the system being sized appropriately.

I have always believed that solar thermal systems should be slightly over-sized - particularly on houses with good insulation - so you get maximum cover at the fringes of the season when the central heating is off. Those fringes have been with us for most of this summer alas....

You can only over-size a system if there is an appropriate heat dump to prevent stresses incurred from overheating. I would personally prefer to see a normal heat dump on all systems, regardless of whether there is a valve present to contain the heat within the heat pipe itself.

So if I was to install a system with 40 tubes and a 300L tank with no heat dump as kingspan recommends, will I not get a 20 year warranty?

quentingargan

Cocoon wrote: »

So if I was to install a system with 40 tubes and a 300L tank with no heat dump as kingspan recommends, will I not get a 20 year warranty?

I assume you will as 40 tubes / 300L ticks the boxes. But if you decided to get more hot water on the fringes of the season by putting 60 tubes in, then it might be a different matter. You would have to check that with an approved installer.

Cocoon

quentingargan wrote: »

I assume you will as 40 tubes / 300L ticks the boxes. But if you decided to get more hot water on the fringes of the season by putting 60 tubes in, then it might be a different matter. You would have to check that with an approved installer.

I measured up for 60 tubes and wont have room on the roof, 40 should be no problem though. Thanks for the reply.

maradonas

call kingspan technical northern ireland for any questions on spec they will answer your questions or other. 30 tubes 300ltrs gives hot water for 4-5 people. heat dumps cost extra but its up to the owner. if your electricity is ever out on a very warm day then any heat dumps are useless. so kingspan has allowed for this probably will still stand over its gear if its serviced annually plus a change of glycol every 5-7 years and remember to put it into holiday mode when you go on holiday which may not happen but the sizing of the system solar pressure vessel pre charged correctly will take the expansion (on an open vented 300litre system which also helps) with only the diaphragm being likely to get any abuse from overheating. anyway all good not made in china yet!!

championc

Cocoon wrote: »

I measured up for 60 tubes and wont have room on the roof, 40 should be no problem though. Thanks for the reply.

Then I would strongly suggest that you don't go for a 300L buffer tank. I would suggest something more in the region of 200 - 240L.

40 tubes with 300L will leave you very short on the fringes or as Quentin says, this summers' weather too !!

If it helps, I am now posting my data to Cosm so it's available to anyone, online, 24 x 7. Not sure yet how to change the timezone in Cosm since time is off by an hour.

See https://cosm.com/feeds/71436

Cocoon

championc wrote: »

Then I would strongly suggest that you don't go for a 300L buffer tank. I would suggest something more in the region of 200 - 240L.

40 tubes with 300L will leave you very short on the fringes or as Quentin says, this summers' weather too !!

How did you fair out today on a very overcast day in Dublin?

BTW I ordered the data logger so I will post some results when the system is installed.

Also I called the guy you recommended and he came in €1500 more expensive than who I went with. Though he was very informative and seemed to know his stuff when it came to Thermomax tubes.

championc

Looks like I edited my post after you started typing.

I have all my old data on an SD Card which uses it's own Steca software but you can keep an eye on my live data from here onwards at

https://cosm.com/feeds/71436

engineermike

Cocoon wrote: »

So if I was to install a system with 40 tubes and a 300L tank with no heat dump as kingspan recommends, will I not get a 20 year warranty?

Hi,
KS have software to configure, K sol or data sol or something its called. The equation goes over the no. of hot water users in the property / aspect of pitch of roof - factoring for times of hot water requirement *& estimated no. of weeks of holiday annually ( also the annual irritation factor for your particular county).
Short answer is yes, if you over size without heat dump - ( most likely a non ks accredited installer ) your warranty will be invalid.
Less effective tubes will probably be fine with 40 tube / 300 L set up. Mind you its possible to dump to a buffer and pre heat the heating loop - our weather is always in flux, south of France in the afternoon - Atlantic will provide north of russia weather in the evening.
A no. of solar thermal companies i work with are big into this (solar thermal heating) in the UK, I guess it all is representative in the %.
I'm closely looking at it, in my mind its better to have energy and dump it some where than to have to pay for it - even a heat dump can be designed with a thermister that dumps to the north face of your property in the evening time.

mike f

championc

Cocoon wrote: »

Thanks for the reply regarding the thermomax tubes as you have first hand experience with them, what I'd like to know is if the higher quality thermomax tubes would require less tubes to give the same result?

Sorry but I was not aware that there was potentially two different qualities of Thermomax Tubes

Cocoon wrote: »

As far as a heat dump goes I still think the thermomax tubes need one especially if you over size the system. I don't think they would see 20 years if they are maxing out all the time.

As I have already confirmed, I have all my data since my system was installed in Feb 2009 and now anyone in the world can view it 24 x 7 x 365 on https://cosm.com/feeds/71436. It would appear that some on here would feel my system is under sized (with 30 Tubes with 180L Buffer) but I can tell you that the system has only ONCE reached a point where the system would auto vent.

So while people are installing systems with Heat Dumps, who says the heat dumps are ever used, or if they are, it obviously depends on what temperature the system is set to, to kick in the dumping. I've set my system to only shut off at 80 deg C

championc

tails_naf wrote: »

I am looking into getting a data-logger added to the system, and motoring the pump start-times and more temperatures.

If your system has an RS232 output, you could consider streaming the output to COSM.COM Just means that you can then monitor your system from anywhere, with an internet connection, even from a phone app. All I needed was a RS232 to USB adapter and a Raspberry Pi.

Cocoon

championc wrote: »

If your system has an RS232 output, you could consider streaming the output to COSM.COM Just means that you can then monitor your system from anywhere, with an internet connection, even from a phone app. All I needed was a RS232 to USB adapter and a Raspberry Pi.

Championc, you will have to give us a step by step instruction on how to configure that set up. Do you have the raspberry Pi connected to your network with a wireless dongle? Also what software do you need to use to get the steca to talk to the Raspberry Pi or is it plug and play?

If its straight forward enough I'd be interested in doing the same, I was monitoring you system today from my phone and its very handy indeed.

championc

Cocoon wrote: »

Championc, you will have to give us a step by step instruction on how to configure that set up. Do you have the raspberry Pi connected to your network with a wireless dongle? Also what software do you need to use to get the steca to talk to the Raspberry Pi or is it plug and play?

If its straight forward enough I'd be interested in doing the same, I was monitoring you system today from my phone and its very handy indeed.

Hi Cocoon,

It's all very straightforward. I have the Pi connected to a remote router which wirelessly bridges back to my main router but there is no reason whatsoever to not connect via a USB wi-fi stick in the Pi. The Pi is running the Raspbian Wheezy 15/07/2012

So once your Pi is connected to the internet, the next thing you need to do is to verify your data stream from your solar panel.

1. If you're a Windows person, get yourself a copy of TeraTerm and verify the streaming of RS232 data onto Windows first.

2. Once you have your pinouts correct, you can then connect your RS232 stream to a Pi via an RS232 to USB adapter.

Consult the following link http://learn.adafruit.com/send-raspberry-pi-data-to-cosm/overview which gave me most of the info I needed.

3. Install the following on your Pi
sudo apt-get install python-serial
sudo apt-get install minicom
sudo apt-get install python-setuptools
wget -O geekman-python-eeml.tar.gz https://github.com/geekman/python-eeml/tarball/master
tar zxvf geekman-python-eeml.tar.gz
cd geekman-python-eeml-a7d2949
sudo python setup.py install

4. Identify your Pi port (likely to be ttyUSB0 - check /var/log/messages) and then run Minicom and verify that you can see the RS232 stream on the Pi.

5. From there, you just need a Python Script to read your data, format it, and output it to COSM. Remember to CHMOD 755 ./scriptname.py before then adding the script to a CRONTAB if you need it to be repeated over and over again.

This is still work in progress but here is my current script.

#!/usr/bin/env python

import time
import serial
import datetime
import eeml
import sys

# Open the Serial Port
ser = serial.Serial(
        port='/dev/ttyUSB0',
        baudrate=9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
)

ser.open()
ser.isOpen()

DEBUG = 1

input=1
out = ''
count = 0

# Check the Serial port for data every second for 60 seconds
# A Crontab job will be running this whole script once a minute
while len (out)<4 and count<60 :
        time.sleep(1)
        out += ser.readline()
        count+=1

if len(out) < 4:
        sys.exit()

#************************************************************
#** CHANGE THE TWO LINES BELOW BY INSERTING YOUR OWN COSM DETAILS **
#************************************************************
API_KEY = 'MY-KEY'
FEED = MY-FEED_ID


API_URL = '/v2/feeds/{feednum}.xml' .format(feednum = FEED)

# Stripping out the data from the string - will re-do with Strip and an Array
TandD = out[1:19]
T1 = out[20:22]
T2 = out[23:25]
T3 = out[26:28]
T4 = out[29:31]
T5 = out[32:34]
T6 = out[35:37]
R1 = out[40:41]
R2 = out[42:43]

# Assumble the data for COSM (Pachube)
pac = eeml.Pachube(API_URL, API_KEY)

pac.update([eeml.Data(1, T4)])
pac.update([eeml.Data(2, T3)])
pac.update([eeml.Data(3, T2)])
pac.update([eeml.Data(4, T1)])
pac.update([eeml.Data(5, R1)])
pac.update([eeml.Data(6, R2)])
pac.update([eeml.Data(7, T6)])
pac.update([eeml.Data(8, T5)])

pac.put()

Cocoon

Thanks for the reply championc, when my solar installation is complete I think this could be a little project for me. In the meantime I will try source a raspberry pi, it doesn't seem to be in stock with a few suppliers. When set up I will use your code and try share the info like you are doing. It would be useful to be able to compare data on two different setups.

championc

Cocoon wrote: »

Thanks for the reply championc, when my solar installation is complete I think this could be a little project for me. In the meantime I will try source a raspberry pi, it doesn't seem to be in stock with a few suppliers. When set up I will use your code and try share the info like you are doing. It would be useful to be able to compare data on two different setups.

Farnell seem to only have a 3 week waiting list. Stay clear of RS. Quoted 11 weeks in late June and emailed me yesterday to say they are now looking at a further 5 weeks delay

barrycoleman

Hi Championc,

I've followed your instructions and it worked liked a charm! Thanks for that.
It took me a bit to find how to get the API_KEY and FEED_ID from cosm.com and where to put them in the script, but I have it working now.

Thanks again!

Barry

oaklands

@Championc

Which rs232/USB adapter did you use.

I would like to know is the serial interface on the SC300(Steca_TR_0603mc) TTL or full spec RS232.

tnx in advance

championc

oaklands wrote: »

@Championc

Which rs232/USB adapter did you use.

I would like to know is the serial interface on the SC300(Steca_TR_0603mc) TTL or full spec RS232.

tnx in advance

I just had a standard rs232 to usb cable that i bought in a pc shop. it's standard rs232 and NOT ttl

oaklands

championc wrote: »

I just had a standard rs232 to usb cable that i bought in a pc shop. it's standard rs232 and NOT ttl

Thanks, so I presume you first wired up a 9-pin D-sub connector on the controller side and then connected the adapter to that?

championc

oaklands

Thanks - exactly what I was looking for