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Rainwater Harvesting
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Tel: 01905 821691 Justin is a solar installer local to Eco-nomical. He and his family are committed to a sustainable way of life, as evidenced by his remarkable 80 tube solar hot water and heating installation (is there a roof under there somewhere Justin?) and his LPG vehicle. In addition to solar hot water installations, he also is happy to install solar pool heating, fits woodburning and multifuel stoves, does general plumbing work and will even carry out tiling and similar if you ask him nicely enough! He has various relevant City and Guilds qualifications as well as being qualified to install and inspect unvented hot water cylinders. If you are looking for an installer within around 100 miles of Worcestershire either let us know and we will put you in touch, or call Justin directly on 01905 821691 or 07834 619080. He would be happy to install an entire system, work with a householder on their own installation, commission a system, attend a breakdown, or just offer consultancy. Also, he will deliver systems by arrangement and offer advice while on site, useful if you are worried about elements of the install! He is a friendly chap, is proud of his competitive prices, and judging by his work he certainly knows his stuff. Justin's installation started off with 2 Eco 58-1800-20's, a Resol RF pumping station and a BS4 controller. Note that it is a work in progress, scroll down the page to see the latest improvements. An interesting feature of Justin's system is that he installed an additional sensor to allow him to determine the exact power output of his system. At the time of writing, his system with 40 tubes has produced just under 3 MWh (yes that's Mega Watt hours!) in eight months. A detailed breakdown of these figure is reproduced below. Impressive as these figures are, bear in mind that summer 2007 in the UK was about as un-sunny as I can remember. The fact that Justin's April figures were the highest for 2007 underlines this point. He also used a BS4 controller that offers variable pump speed depending on temperature differential, which reduces both wear on the pump and electricity consumption. We look forward to seeing figures for the new enlarged collector field. Justin writes:
"Hope you are well and business on the Solar front is going
well. Sorry for the delay as I managed to finish my Solar installation
at the end of January. System has been running very well throughout February,
I have pump running readings for this month at 79 hours and total KWH of 124
(able to generate this info using the 4th sensor I purchased from you guys).
This is very impressive considering the weather over the month, I even manage
65 degrees for 250 Litres of water in one day!!! Total output for the
month figure would have been higher but I only just installed the shower so
not really using much of the hot water generated this month" (remember
that a solar collector works more efficiently the cooler the solar fluid.
If the temperature of the water in the cylinder is already high, the power
output of the collector will reduce. See here
for more figures about this).
Justin continues:
"Setup as follows;
Albion 250 Litre Eco-Cylinder
2 x 20 tube 58mm Panels
Resol Pump station
Resol BS4 Controller
Total antifreeze contents of system is 5 Litres
Bar setting 2.4 (I will be monitoring this in the more
productive months)
I did explain to you previously that I had restricted the
flowrate to 3 litres per minute. After further investigation, I realised that
the BS4 controller came in trumps with its variable pump speed. Set pump speed
at 50% (3 Litres per min at 50%, 6 Litres per min at 100%) saving unnecessary
wear on the pump and also using half of the electricity. The BS4 increases
speed by 10% every 2 degrees above a set level (on setup program) as panel
temp increases. Considering it only cost about £20.00 more, I will some recoup
this money and not go through so many pumps. Maybe worth mentioning to your
customers? Also just a note on the AAV (automatic air vent), I found the most
effective way to remove air from the system was to leave the system to it's
own devices for about 5 days (the heat generated seems to move air much
better than a cold solution)".
I assume that this is because water varies a surprising amount in viscosity depending on temperature. "For these 5 days I left the isolation valve open and then closed at the end of the 5th day sealing the system, this worked very well. I have also added extra insulation to the cylinder to reduce heat loss. (Loft insulation space blanket 200mm) This has slowed down heat loss and allows water to go a little further when weather is poor. I found the traditional hot water jackets very poor and the loft space blanket was very easy to install!
I would just like to say many thanks for your help with
this project and have already recommended a few people to your services. I
found that you guys were very helpful but also allowed myself to decide
exactly what I wanted to buy. Many thanks for your patience and helping me to
achieve a great result. As promised I have a number of photos I will post for
you tomorrow, if you could just let me know when they arrive? If you wish to
use any of this info or photos to promote your product then feel free to do
so.
Finally I anticipate that this system will give me free hot
water for approx 9 months of the year and still contribute in the remaining 3
months depending on weather conditions. With the removal of the 10.5KW
electrical shower I anticipate that I will save approx £250.00 per year off my
electric bill with a payback in the region of 5 to 6 years to break even.
Many thanks again for all your help and I wish you all the
success in this growing market"
and a few days later..
"Will keep you up to date on the all the info I generate,
will e-mail my monthly results. Great results for the first 2 day this
month. Generated a total of 24KWH and ended up with 250 Litres of water at
65 Degrees, a new record for the system!!!
Just had my electric bill and prior to installation was
using 13 day and 13 night units. Amazingly my day units have now gone down
to 5 day units. This does sound like a lot but is saving approx £0.80 a day
in electric. Work that over the year and that's a real saving! (Those 10.5KW
electric shower cane your electric) This has without a doubt accelerated the
payback period and who wants to use those kind of KW's for a cold shower in
the summer? Just for your info have installed a Mira Exel (Gravity System,
as my pictures show the 50 gallon cold water tank but of course you could
get away with a smaller one if required".
The figures shown below up to the end of October 2007 for Justin's original 40 tube collector field, and after that for his enlarged 80 tube field. Records in this form began in March. The BS 4 controller shows the number hours which the solar pump is operating. By knowing the temperature of the solar circuit in and out of the hot water cylinder, and the flow rate, it is possible to derive the amount of energy produced. Justin records these figures monthly, the per day figure is average for the month. the Bypass column shows the number of hours the heat dump circuit is in operation. The Per Solar Hour column shows the average output of the array for each hour in the month that the solar circuit pump is in operation.
All of the above information from Justin refers to his original 40 tube installation. Scroll down for new pictures of his 80 tube setup. Justin has recently provided updated information about his electricity usage before and after his solar installation (he previously used electric showers and an electric immersion heater for hot water, in the absence of gas). This shows even better savings. Comparison of the two winter periods shows expenditure of £1.93/day before the solar installation and £1.03/day after. He has actually cut his electricity consumption by 50%, in the winter, but the difference in day and night unit costs accounts for the actual savings of 46%. Justin has reduced his carbon footprint, by about 5.5kg/day in the winter! The summer figures are obviously much more positive because there is far more sun (bearing in mind this is for hot water, not heating)..
Justin made improvements to his system at the beginning of 2008 as follows: Resol BS4 Controller has now been changed for a Resol ES controller. This allows up to 10 different temperature probes and lots more pumps used on 36 different programmed setups ranging from single stores to incorporating solid fuel boilers etc. I need to make this change due to the installations of a secondary hot water cylinder. Also allows connection of CS10 & V40 measuring instruments (see below). Installed a second hot water cylinder with 2 coils sized at 180 Litres. This now means I have 430 litres of hot water, allowing me to make full use of the 4 collectors now mounted on the roof. Incorporated into this setup is an Eco-nomical 3 port valve. The ES controller monitors both separate water stores and heats the primary store to 65°C. The controller switches the 3 port valve once this temperature is reached and starts to heat the secondary store. This now means that rather than having cold water entering my cylinder at around 10 degrees it is preheated and also due to the low water feed temperatures allows my system run more efficiently. (Feb 6th there was 60 degrees in the Primary store and 40 Degrees in the Secondary store, a good result for the beginning of Feb) A great function of the ES controller is a function called ‘TRUN’. This monitors the collector temp against both stores. After a set time (currently 15 minutes) it will automatically start loading Secondary store if the Primary cannot be loaded. This makes use of heat in the collector that would be otherwise wasted and transferred into the Secondary store. The run times can be changed but I have required my system to check every 15 minutes and run for 5 minutes in temperatures allow. A Resol CS10 sensor has now been added to allow measurement of sun intensity in W/m2. This is mounted next to my collectors on the roof. A Resol V40-0.6 Flowmeter has also been installed along with temperature probes on flow and return solar pipe work. This is a water meter style flow meter which allows the output measurements of my system to be recorded with greater accuracy. I will make sure all is operating correctly in February and start recording system figures from March. If all goes well I will introduce a Resol Datalogger to record all figures automatically. Due to the size of my array I now have released the second coil in the primary cylinder for the ‘Heat Dump’ and have moved this to the coil on the Secondary store. This will allow me to keep the Primary store up to a good temperature and bypass from the Secondary store that is feeding the Primary store. Total output of this heat dump is 3.5 KW at water temperature of 70 Degrees and is completely independent to the solar system. Control for this section will be made through a Resol BS4 controller that I also intend to also use for controlling my solid fuel burner Backboiler. These heat dump radiators are positioned in the Conservatory 1KW, Bathroom 500W and a 2KW radiator in the loft area. The loft radiator is not used in cooler weather when heating is required. I would expect that these radiators will start operating from Mid Feb, depending on the weather. System overview as of Feb 08; 4 x 20 Tube 58mm Evacuated Tube Collectors Flowcon RF pump station Resol ES controller currently using ‘Array 5’ setup 250 litre vented primary store cylinder 180 litre vented secondary store cylinder Eco-nomical 3 port valve Resol CS10 irradiation sensor Resol V40-0.6 flowmeter
The automatic air vent. this is the correct place to fit it, at the highes point in the system. Note the attention to detail shown in the insulation on this and the following picture. Think of insulation like a bucket. It is easy to leave difficult areas with the idea that it is only a small part, but that is just like a bucket with only a small hole. The heat will leak away like water.
This is Justin's super-insulated hot water cylinder. Even a new hot water cylinder with insulation that meets the building standards will lose a surprisingly large amount of heat. A simple, cheap measure which as Justin says, is easy to install.
This is the BS4 controller. Justin opted for the Resol RF pumping station which does not have a built in controller, because he wanted the pumping station in the loft but the controller easily accessible in the house.
The loft plumbing, showing cold water tank, pump station and expansion vessel.
The following pictures are of Justin's newly expanded 80 tube collector array.
Here are some pictures which also show the installation of Justin's neighbour, Salvi Reilly, which is separately documented here.
Thanks for the information and pictures, Justin.
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