Solar water heating
Click here to go to the data logging page.
For some time I had been thinking about whether I could make use of some renewable energy and in Spring this year (2009) I decided to have a go with some solar water heating. A friend of mine had a system installed by Solarworks a few years early and was pleased with the results so I decided to get a quote.

There were a few things to arrange before the work could start. Grants are available from the Energy Saving Trust® providing 400 for a system such as mine. However, I needed to install some extra loft insulation to get me to the minimum requirement of 270mm.

I chose Knauf Space Blanket to do this because it had a convenient covering that made the installation easier and many DIY stores were offering frequent two-for-the-price-of-one deals. One section of my roof space needed 200mm and the other needed a little more. For that section I used two layers of the 150mm type. It is important to get the application for the grant in before committing to the installation but the on-line application sends back confirmation of approval right away.
Once I'd sorted the loft insulation I also needed to check on planning permission and building control requirements. This wasn't easy because the local council were a bit non-commital about what was permitted without planning approval. In the end I took their guidelines on what could be done as sufficient to confirm I didn't need planning permission. I also made a building notice submission - which also took a while because they were unclear on what the correct fee should be. In the end they were able to confirm it was classed as "Certain small works".
Having done all that I could give Solarworks the go-ahead to install the equipment. This was a really quick job and they finished it in less than a day although normally allow two to be on the safe side. I needed to get the building control inspector in to check the work on the day so that he could confirm it met the regulations and issue the appropriate certificate.

The quality of the work was very good and from the installation in July up to late September I'd needed virtually no gas heating of my hot water. The pictures here show the tubes on the roof and the new tank and plumbing in my airing cupboard. It's advisable to install a larger tank to get the maximum benefit and although I probably wasn't going to consume a large amount it is a good idea to go for something that fits the size of house so that future re-sale value is achievable.

Once I had the receipt and installation certificate from Solarworks I could apply for payment of the grant that had been authorised earlier.

The other part of the project was to get some data logging set up so that I could monitor the performance and potential savings. I had chosen a controller with the necessary serial interface to connect to my computer. The controller is the RESOL DeltaSol® BS Plus - not to be confused with the BS Pro which doesn't have a serial interface.

There was quite a bit of information on the web on how to collect data from one of these controllers. In the end I put together a script to capture 15 second blocks of data every 5 minutes from the COM port on my Mini-ITX server running Linux. The data captured is processed using some C++ code and the output from that compiled into graphs and log files and uploaded to my web site using some Perl scripts that I wrote.

I'm going to put some more information on here soon about the details of the interfacing but if anyone wants help with this then please feel free to contact me.

During April 2010 I added a return flow temperature sensor. This is a pipe-attached version (FKP21) of the sensors that measure the tank temperatures and was quite easy to fit and connects to the S4 input on the controller. Once configured with the type of anti-freeze in the system and the flow rate, the controller can calculate the amount of energy transferred into the tank. I've added the results to my data page as a daily log running since 25th April 2010. It's worth bearing in mind that the amount of heat transferred will be affected by consumption as well as the available supply from the sun.

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