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A personal record of my renewable energy initiatives for Solar Panels and heating with Solar for Hot water and radiator heating by evacuated tubes

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Solar Panels - Want to perform a DIY Solar Panel Installation yourself ? get solar hot water from the sun - Renewable green Energy is the way to go !

 

The following describes my experience in DIY Solar Hot water solar panel installation via evacuated tubes (with some capacity left over for radiator heating) This is a personal site promoting the use of green energy in these times of climate change , and hopefully giving some insight in a plain and simple manner on how to do a little bit for the planet and your pocket in the long run. The following is a blog if you like of my own experiences for my own installation in  Basingstoke, Hampshire.
This is my first install of a Solar system and the results have been very encouraging - I now want to do more in the green initiative field to my property. I have installed my panels in my property in Hampshire - when sizing your system the position in the country will make a difference to the collector area. I consider my install bigger than most - yet I still want more ! but there is no doubt as we are into Oct 2008 that I am saving money and will continue to do so for many years. My aim is to reduce my carbon footprint, I have hard evidence my gas usage is going down and I aim to be carbon neutral in hot water soon. If the install costs are putting you off, remember many sites do not mention these add value to your property should you ever decide to sell so its not just the energy costs your need to recoup. DIY Solar kits are coming down in price while fuel prices rise.

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The System - Resol BS/4 Controller with a Resol Flowcon pump station, twin coil tank, expansion tank and large radiator dump 10600 BTU for excess heat plus -

The evacuated solar tubes, 90 in total comprising 1 set of 30 and three sets of 20
each tube is 58mm Diameter by 1800mm / 1.8 meters long
The 30 Tube array is 2420mm wide by 2010mm high = 4.9m2
The 20 Tube array is 1680mm wide by 2010mm high = 3.38m2
More Info on the Solar Panel Installation
Solar Panel Diagram

Domestic Solar Panels - Solar Hot Water

South Facing with large domestic solar panel install

Large Domestic Solar Panel Installation

The Tank

Solar Heating coat cupboard Start off by thinking where you want the tank - sounds obvious but they can be much larger than your usual domestic immersion heaters and you could loose your space in an airing cupboard.

I was lucky enough to have a double length coat cupboard in my lobby area so I stripped it out and prepared a space as seen.

remember once the tank is in - its in ! so now is a good time to paint and make any changes required. I also built a small platform for the tank - the connections are very low to the bottom and this makes it easier to drain and maintain etc.

The wall on the right is external so I battened, and insulated the wall and plaster boarded for additional heat retention .

One Copper tank, twin coil tank 300 Litres (54 Gallons approx) standing 1850 mm high (just over 6 foot)
twin coil Solar tank - large solar tank Note silver band at the top of the tank.

This is builders strapping and was pre installed and securely attached to the wall prior to the tank going in. As the tank is 6ft tall its just precautionary (piece of mind) to ensure the tank remains firmly in place.

All joints in the cupboard are compression fittings in the event that the tanks needs moving or replacing - In addition the solar side can get very hot and though the manufactures advice is "no solder joints near the collector", I have erred on the side of caution and have the bare minimum of soldered joints throughout.

Note the wooden batons on the side which held the original Radiator dump now increased in size and moved into the loft when I installed more tubes on the roof. - I only use this as a solar heat dump as I have also installed three more large radiators in the house for daytime heating.

More Information on the twin coil solar tank installation.

The Resol Controller
resol bs 4 deltasol controler I use a Resol BS/4 solar controller which includes 4 temperature probes and two relays including a variable pump speed output - the Internet contains plenty if info on these great little controllers so I will not go into great detail.

I run the system fairly hot, up to 70c before the overheat settings kick in and dump the excess to a radiator. I installed the system end July 2008 and even with our poor sunshine record the tank, all 300 litres would heat up in a full day

There is the safety issue of very hot water coming out of the taps - therefore I have a mixer feeding the whole house

As autumn is now with us I have reset the controller to reach 50c on the hot water tank and then divert to the radiator - free solar heating generated later in the day.

Flowcon Pump Station - Flowcon A The Pump Station is a Resol Flowcon A - comes with a flow meter, drain and filling points and the pump itself.

It also contains the pressure relief valve, the picture of the tank above shows a partially installed drain pipe to the outside. this must have unhindered access to the outside for obvious reasons.

The pump speed is set to minimum and consumes 43 watts and the controller runs the pump at 30% speed in most cases so consumption is approx 15 watts plus another few watts for the controller.

Insulation

Every pipe in the systems with the exception of the heat dump and around the pressure vessel is insulated - I have used armaflex pipe in 2 metre lengths which is designed for very hot pipe work and common for a domestic solar installation. Unlike normal foam pipe this insulation is not as ridged and does not have a split in for retro fitting, therefore it must go on as you plumb and put joints etc in. In hindsight I would recommend going for the thickest/best insulation you can afford - I have found that in the loft the heat can be easily felt when touching the outside of the insulation so there is scope to cut down on loss. I am looking to further wrap the pipes in some way.

Radiator Heat Dump.

I have double radiator (double fin) 1800mm X 600mm in the loft to dump excess heat from the panels. For additional safety and as a backup this is fed by a second pump giving me two pump options to remove heat from the panels and keep them in good working condition without excessive heat build up. In addition to the radiator solely used for dumping heat I have a further three very large single panel radiators in the house that give me 15400 BTU of heat in the house during autumn and spring running on the same circuit. I could fully automate this but at present twice a year I just turn of the valves to the dump radiator and open up those for the house heating. Works great, in early march I am getting 47oC in the house which runs from about 9.30am to 15:45pm on a sunny day, enough to keep the house warm and effectively free heat and free energy . MORE INFO ON RADIATOR DUMPS IN MY SYSTEM

Venting

The Solar side is a pressurised system with an expansion tank - not much to say here - under manufactures instructions a suitable high temperature automatic air vent has been fitted at the highest point inside the roof just under the apex so its accessible and out of the weather. Took a while to get all the air out when several pump runs at high speed but after a few days no noise, no bubbles, no problem.

Pipe work - General.

All pipe work is 15mm copper with the exception of the pre supplied manifolds and pump centre. with experience do not under-estimate the cost of the pipe itself but more importantly all the compression fittings you need. I run the initial system first with plain water to test for leaks (with no tubes in place) surprisingly no problems and no pressure drop. However - when re-filling with a glycol based antifreeze and letting the system heat up to maximum temp I had a few weeping joints. - Not easy to track down with the insulation covering everything and not just as simple as tightening a nut in a couple of cases but still soon fixed.

I fitted a small spur to the pipe work in the loft specifically to fill the system Has its own shut off valve and threaded connector which I used to connection a modified garden pressure sprayer to. I found this easier than using the pump station to fill - the higher in the system the less pressure , I had room to move and the pressure washer reached the pipe easier than the pump station which is halfway up the wall in a cupboard..

Antifreeze

Not just an Antifreeze but also a glycol based heat transfer fluid - my system took just over the 45 litres , don't expect to use that much -I have 4 solar headers and some very large radiators in the system plus a large Double in the loft as a heat dump.

My Recommendations/Thoughts

Investigate the systems on the market yourself through the internet. If your doing your own install think beyond the immediate timeframe unless you just want a bog standard leave it alone system. I am looking forward to the future where I can use a more advanced controller to automatically divert heat by time of day, by further temp sensors etc.

Its still worthwhile looking to supplement low level heating as I am going to do - the current radiator I have as a dump could be bigger and run slightly cooler to extract more heat from the panels. I could increase the number of tubes for more radiator heat , but in summer I'll have too much unless I dump more or store additional hot water so this is under consideration for the best way Forward.

Dec 26th 12.50am - Update on performance - Its 2 to 3 c degrees outside in lovely winter sun - I have manually set the controller to divert all heat to the dump radiator in the house as I have enough hot water stored - It is with great satisfaction that the panels and thus the radiator are running constantly at 50.5 degrees heating the home to some extent and drying some washing. Make me more convinced to add another 20/30 tubes to the roof and put in a larger dump radiator to extract the Autumn through Spring solar heat, add a second smaller single coil tank to act as a store/pre heat and dump and move the existing dump radiator in the loft.

Early Jan 09 - Several days of continuous minus temperatures - the tubes have a coating of heavy frost on them but they are still heating the water and running at plus 20c - just shows how the vacuum works so well and the sun penetrates through the icy coating.

As part of my investigations I also visited the Centre for Alternative Technology in Machynlleth in Machynlleth which gives a great sense of inspiration and help in making the right decisions with plenty of working installations to see and get ideas from, they may also be able to offer advice. I am also looking to install Photovoltaic panels this summer to supplement my electricity bill, some impressive examples to be seen at the centre for alternative energy and this has spurred me on to go for it as soon as I can afford to do so.

The future - I have now added another 40 tubes to the existing 50 tubes = 90 tubes at approx 15 square metres area has got to be up there with some of the UK's largest domestic installs for hot water and heating ( there's always one bigger though ! - somewhere)

Photovoltaic panels will be next - (when funds permit) though running out of south or near south facing roof space - need to win the lottery for this project though I may consider a small panel for the pump on the solar water heating. I can then say I am carbon neutral on hot water and with some considerable saving on the heating.

A summary of Performance over time

The Savings -
I have been taking Gas readings for the last 3 years that I have been at my property and therefore have some accurate history to base savings on. I must stress we have always been energy conscious and use gas wisely so I would consider our household to already have lower consumption than the average household.

Based on my current install that was completed with two panels Aug 08 and with another two panels added in Jan 09 I have hard evidence that I am 15% down on gas usage. Remember this is a saving through the winter period and plus we have just had the coldest winter on record for 15 years. I anticipate that the Gas boiler will be turned off by the end of March 09 with the radiators heating the fabric of the house sufficiently to take us through the night and with ample hot water. Not only have we reduced gas consumption, we have hot water now consistently rather than heated on demand.

April 09

The Gas to the boiler was turned off 2nd April 09 with the panels now providing all the hot water and some heating - The tank reaches maximum temperature in the afternoon and the controller goes into overheat protection - though in our case this diverts to two radiators in the centre of the house. Enough heat to carry us through the evening and the overheat automatically turns off again when the tank drops 1/2 a degree.

May 09

Excess heat and more than enough is being generated now and the third dump radiator in the loft has had the valves opened up - still heating the house internally for the chilly nights but dumping some of the excess out through the loft - system is automated and working well - how satisfying to see the gas readings remain constant. - will soon turn off the radiators in the house to stop it turning into a sauna .

Our Gas unit usage is down 39% so far compared to the same period last year when we had nothing (even with this years record snow fall) the full 4 panels only went live in Feb so I expect this figure to climb much further. We now use approx 2 whole units per month as the only appliance is a 4 ring gas hob

Sept (Mid) 09

I can confidently say we are now in mid September and the boiler had the power shut off beginning of last April, still getting a full tank of piping hot water and still diverting heat to the radiators in the latter part of the day. I am still running the tank very hot and it will be soon be time to adjust the controller down to 55c which is what the original boiler heated the temp to. With the reduced tank temperature I can start diverting heat to the radiator and heating the house as the nights start to get chilly. (not there yet though) I have gone nearly 6 months with zero gas usage on water and heating and expect to reach the full 6 months and more which is very satisfying.

Feb 2010

A New year and where's the sun gone !
Well we all know its been a poor winter and I am only getting top up heat to the tank with just a few days of full winter sun enabling me to switch to solar radiator heating during the day. Can't say I am disappointed, not in the system but the weather as the same time last year we were getting most of out hot water from the panels. Looking positively though the days are getting longer and the sun is getting higher so even on a cloudy day I am getting some heat from the system. I have mentioned this before but during our last spell of heavy snow when Basingstoke hit the national headlines, the roof was absolutely covered with deep snow but the next day it was minus outside and full sun the panels were still generating heat. The vacuum tubes did there job as it would not melt the snow.

March 2010

Early March and the weather is much improved - as last year I am getting close to 50oC at the radiators and still managing to heat the water. Anticipate the boiler will be turned off again by the end of March.

April 2010

Spoke too soon about the warm days in  march  - back to normal English weather now with the heating supplementing the solar ( or visa versa)
 

O)ct 2010
I have installed a fourth solar radiator in a north facing bedroom  and run the pipes all the way back to the existing system  though can only do the final reconnection one evening in the autumn when the system is not constantly running hot.

Calculated my total 2009 gas bill and it came to £350 for the whole year heating and cooking in a 4 bed detached bungalow - very pleased with this.
I used actual invoices from confirmed readings so this is accurate.

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