Part Forty Two – Water Treatment

This blog entry is just looking in detail at the ozone treatment part of our borehole water system.

Our borehole water has a high concentration of ferrous iron, this is what’s often called “clear iron” as it doesn’t colour the water.  It’s fairly common in water drawn from deeper aquifers, particularly in areas where there are natural iron deposits or soft (often slightly acidic) water that dissolves iron (and other metals, like manganese) from the surrounding rock.  In our case our water comes from the Lower Greensand formation, an aquifer that is known to have water with high concentrations of ferrous iron as well as dissolved hydrogen sulphide gas (the “rotten eggs” smelly stuff).

The traditional way to remove ferrous iron, manganese and hydrogen sulphide from water is to just add oxygen to it, usually in the form of air, but it can be by using an oxidising catalyst.  The most common oxidising catalyst is manganese dioxide, used in a filtration bed.  This works OK, but it does eventually need replacing, or regenerating in some way, as it will lose its ability to oxidise after a time. Continue reading “Part Forty Two – Water Treatment”

Part Forty One – Hot Water At Last!

This forty first entry was published originally by JSHarris on the 21st November 2015 and received 1,244 views on the closed forum


After battling with a stomach bug for over a week, I finally managed to get the Sunamp PV in place and installed.

Installation was generally exceptionally easy, with only two areas that caused some challenges. The first was manhandling the sheer weight of the unit up stairs. It isn’t very heavy (around 75 kg) but it is small and very dense, meaning a two man lift is the bare minimum. The second challenge was getting at the pump vent plug when commissioning it. It’s set inside the top of the unit but very close to some adjacent pipe work, so a very marrow key is needed to get in and open it up – there isn’t enough space for a dumpy screwdriver. I happened to have a flat key that was intended to fasten the mandrel sockets on my hole punch set, and that proved ideal, so a suggestion is that such a key could be provided as a bleed screw tool. Continue reading “Part Forty One – Hot Water At Last!”

Part Forty – Getting Into Hot Water – Episode Two

This fortieth entry was published originally by JSHarris on the 30th October 2015 and received 787 views on the closed forum


Continuing on from the last entry, here’s some more detail about installing the Sunamp PV and the plate heat exchanger pre heat system.  Here are a couple of photos of the way the plate heat exchanger, its circulating pump, flow switch and the 50mm layer of insulation was applied, before fitting the Sunamp PV in front of it:

Continue reading “Part Forty – Getting Into Hot Water – Episode Two”

Part Thirty Nine – Getting Into Hot Water – Episode One

This thirty ninth entry was published originally by JSHarris on the 22nd October 2015 and received 1,066 views on the closed forum


As some will already know, the hot water system has been a bit vexing, with significant over heating problems from the heat loss from the thermal store, severe enough to damage the veneer on one of the doors. The next couple of entries are going to focus on work to redesign the hot water system to reduce the heat losses, yet retain the ability to use excess generation capacity from the PV panels to heat our water and provide a backup system for periods when the solar panels aren’t generating.

After trying several ways to try and reduce the heat loss from our 260 litre thermal store, from reducing the temperature through to adding lots of additional insulation, I finally decided that the whole system needed to change. The catalyst for this decision was the introduction of a new phase change heat storage system to the market, a compact unit that is able to store excess electricity generated by a solar panel installation (or cheap rate E7 electricity) as thermal energy, called the Sunamp PV (see here: ). Continue reading “Part Thirty Nine – Getting Into Hot Water – Episode One”

Part Thirty Eight – Heating And Cooling Controls

This thirty eighth entry was published originally by JSHarris on the 1st September 2015 and received 1,496 views on the closed forum

As with all things associated with this house, it took me several goes to get the heating and cooling control system to work properly. Despite having done masses of calculations that showed the house didn’t really need much heating, I couldn’t, in my heart, accept this. We’re conditioned to houses in the UK needing heating, usually a fair bit of it and often through large parts of the year, when we get sudden cooler spells in normally warm weather. I started off thinking I couldn’t buy an off the shelf system, so built a home brew DIY controller, and and then spent hours writing and rewriting control code. Finally it dawned on me that there may come a time when I wasn’t able to write code, or that someone else might have to work on the system, so I had better switch to using off-the-shelf parts. Continue reading “Part Thirty Eight – Heating And Cooling Controls”

Part Thirty Seven – A Long Tale About Water (And Life…..)

This thirty seventh entry was published originally by JSHarris on the 9th August 2015 and received 2,583 views on the closed forum


I know I’ve not been diligent in updating this blog, but it all comes down to one thing, WATER. The borehole saga is recorded elsewhere in the blog, but suffice to say that we have had massive ongoing water problems since, with many solutions being recommended and tried, most failing and many involving encounters with supposed experts who quite clearly were anything but. Anyway, this entry will be updated over the next week or so, as I hopefully work towards a solution that works. I’ve lost count of the number of variations on filtration etc we have tried, all failed to some degree; either in that they just didn’t work at all, or that they were too cumbersome, noisy etc to be a practical solution for us. Continue reading “Part Thirty Seven – A Long Tale About Water (And Life…..)”

Part Thirty Six – Winter Energy Consumption For Heating

This thirty sixth entry was published originally by JSHarris on the 29th December 2014 and received 1,188 views on the closed forum

Just a short entry this time to highlight energy use during this cold spell.

On Christmas Eve, at 15:00, I read the import and export meter readings, left the house heating on to maintain an internal room temperature of 20 deg C 24 hours a day, and went home for Christmas. I left the PV energy diverter on to keep the hot water system running, and the mid-point half way up the height of the thermal store was the same temperature when I got back today as it was when I left on Christmas Eve, 55 deg C.

I got back to the the house late this morning, around 11.45 am, and read both meters again. The import meter recorded that the house had used 29.8 kWh to maintain it at 20 deg C evey day, and the export meter showed that during the same time period the export meter showed that we’d exported 39.5 kWh from the PV system.

So, on average, the house used 7.7 kWh per day to heat, but generated 10.2 kWh per day. On the face of it, this looks like the house is (with no occupants and no DHW demand) actually generating more power from the PV system than it is using to maintain a room temperature of 20 deg C, 24 hours a day, during this cold spell (it was -5 deg C when I got to the house this morning). Continue reading “Part Thirty Six – Winter Energy Consumption For Heating”

Part Thirty Five – Hot Water And LEDs

This thirty fifth entry was published originally by JSHarris on the 13th December 2014 and received 2,255 views on the closed forum


I thought a bit more detail on the hot water system and some of the pitfalls of using LED lighting might be useful. I’ve added an instant water heater to the thermal store mixer valve output to allow for occasions when the thermal store temperature drops below that needed to deliver useful hot water. I’ve also found a few failings with using LED lighting that are worth sweeping up into one entry, in the hope that it may help others not make the same mistakes.

The hot water is provided by a combination of three energy sources now. The thermal store is pre-heated to around 35 to 40 deg C by the air source heat pump, whenever that is running in heating mode. It is then boosted up to around 70 deg C by the immersion heater, which is only driven by excess electricity from the photovoltaic panels. Whenever the panels are generating more power than the rest of the house is drawing, the excess is fed to the immersion heater. On bright days this will easily boost the thermal store up to temperature, but on cloudy winter days I’ve found that it often does little or nothing to increase the thermal store temperature at all. I only discovered this recently, with the onset of winter and the rapid drop in PV output. Continue reading “Part Thirty Five – Hot Water And LEDs”

Part Thirty Four – Things Are Going Slowly – And Some Hot Water Stuff

This thirty fourth entry was published originally by JSHarris on the 29th November 2014 and received 1,256 views on the closed forum


I seem to have been working hard on the internal side of the house for weeks now, but with little outwardly to show for it. At least all the flooring is completed, and the ground floor architrave and skirting is pretty much all done (except my study, which is still a store room), and most of the upstairs architrave is on. I am regretting opting for oiled oak internal joinery in some ways, as it’s taking a LOT longer to fit than plain old painted softwood. Looks OK, though.

We made a late change of plan and decided that, rather than have a fitted wardrobe along one eaves wall of the main bedroom (which would have hampered access to the service space in the eaves, via the small doors I’ve fitted) we’d have a walk-in wardrobe. Space was a bit tight, in terms of depth, because of the location of the bathroom door, but by making a thin partition wall I think I’ve managed to make it work OK. The wardrobe has ended up around 3.6m long by just over 1m wide internally, and this seems to be OK for loads of hanging space, plus shelves and drawers at the ends and enough room to get in sort of sideways at the hanging space. I’ve fitted another oak door and lining in the centre, so the right hand side is a “hers” space and the left hand side is a “his” space, with room access the “crawl door” into the under-eaves service area. Each side has 1.2m of clothes hanging rail, plus around 1.2m² of shelving/drawers, plus storage at floor level for shoes etc. It’s more wardrobe space than we currently use, I think, so should be OK. It’s taken a fair bit longer to think up a way of building it and actually getting the frame in and skinned than I thought it would, but has ended up being a lot more solid than I expected, even though the partition wall is only 52mm thick in total. Continue reading “Part Thirty Four – Things Are Going Slowly – And Some Hot Water Stuff”

Part Thirty Three – System Details And The Bathrooms

This thirty third entry was published originally by JSHarris on the 4th September 2014 and received 2,097 views on the closed forum


Following a few questions on the old Ebuild forum, and as I’ve had a serious re-think after some experience of the way the house behaves through a winter and most of a hot summer, I thought an update on the final system I’ve installed might be helpful. The most important observation is that heating is not an issue, in fact I very much doubt if the house will need any significant heating in winter, as it gets very warm just from the heat of the occupants. Working in it over December and January we found that tee shirts and open windows were needed by mid-morning and we never once needed any heat. In fact we had to stop using the 400W halogen work lights and replace them with low energy ones, as one of the halogens running overheated the house pretty quickly even in cold weather. Continue reading “Part Thirty Three – System Details And The Bathrooms”