Renewables

rick

rick

Active member
Joined
Aug 31, 2014
Messages
1,905
Reaction score
6
Location
Warwickshire UK
Does anyone here have renewable energy running?
Our gas boiler is on the way out and I really want to kick it out and replace with something more sustainable, probably a mixture of solar, 100% renewable electric and possibly an air heat pump. I have some ideas as to what would work but the information out there is so sparse when it comes to doing the calculations and picking a way forward.
I see it as a bit of a challenge - a Victorian terraced house with a fairly small back garden is not a promising starting point but the problem needs solving as new builds will take a very, very long time to be the norm.
I've found one forum with a handful of posts, mostly questions without answers except for sales pitches from a particular business interest. Usually solar PV installers. Data/specs for products seem to be cards kept face down - like with Dimplex who will only sell you a storage rad through a partner installer who will decide what you need for you. The whole thing is dressed in the assumption that renewable tech is very complex - it really isn't but without detailed data on products its a closed shop.
A little frustrated, and all the talk of this being the last decade to sort it out will just be hot air unless things get moving!
 
I can't help, but I know exactly how you feel! My late husband was very interested in what was called then "alternative technologies ". And I'd love to move away from oil and solid fuel for heat. But I wouldn't know where to start - and my income is too small, I couldn't afford loan repayments.
What I do have as alternative heat is radiant panel heaters. They're ceiling mounted. They're very comfortable, and fairly reasonable to run. My bungalow is old, and although we insulated the attic and walls, the concrete floors are a problem, especially in the huge kitchen.
A terraced house does have the advantage of being "insulated" on either side by it's neighbours.
I've thought about air heat pumps too, but I quickly get bogged down in technical jargon that means absolutely nothing to me, so I quickly give up!

Sent from my SM-A415F using Tapatalk

 
Is the Centre for Alternative Technology still operating in Mcynelleth (i know that spelling isn't right!)? We used to get newsletters etc from there - they were ahead of their time.

Sent from my SM-A415F using Tapatalk

 
Great idea! I think the Centre is still running and they should be the go to library for this stuff.
Unfortunately, Air heat pumps are pricey and ground pumps with bore holes frightenly so! They would be worth it in the long run and I'm pretty sure having a bore hole you could add the value to the house easily - but yes, big investment.
I'm liking the look of solar collectors for hot water as we have a perfectly south facing roof.
 
This is the link you need for Machynlleth https://cat.org.uk/

A friend of mine replaced their gas boiler with an air heat pump and it was a total disaster! It has since been removed and sold on eBay.

It appears that despite the claims made, they only really work with underfloor heating where the water temperature is lower than a radiator system. Also they do not work well with micro-bore heating pipes. So that was a useful lesson for me because I have radiators and micro-bore pipes and had thought when my oil fired boiler needs replacing that I would go the air-source heat pump route.

I have had PV panels installed and it has changed the way I do things. No longer does the dishwasher or washing machine go on at night but during t he day to make use of the electricity generated.. When I can afford it I think I am going to go for the battery system where the battery is topped up, if necessary, from cheap electricity bought from the grid. Off hand I can't remember the name of the firm - think it's Social Energy? I haven't has them long enough to judge the effect on my electricity costs overall - my bill is lower and I do get the Export Guarantee Tariff but at the moment I have a loan repayment for the panels.
 
In 2007, we installed a Solartwin panel which heats the hot water without using any electricity as a pump. It has a small PV panel which generates enough electricity to pump the water round the panels and back into the cylinder in the airing cupboard. It’s very effective in summer, heats the water to 60+ degrees most days when there’s good sunlight, and backs up the boiler by contributing several degrees even in midwinter. In fact in summer the water is often hotter than we need for weeks on end, with no need to use the boiler as a boost. In our hard water area the Solartwin does need water which has been through a water softener to prevent the tubes from scaling up, so we have to buy salt for the softener, but there are other advantages to our appliances and pipe work to having the water softened.
We also have 6 solar roof panels, the largest number which would fit our roof in 2009 next to the Solartwin. These have generated £700 of electricity rebate per year, which goes a long way to paying for our total power bill. Newer panels would no doubt be even more efficient, but it’s not economic to replace them once they’ve paid for themselves after the first few years. Actually the savings are even greater because we have a very old electricity meter, which I believe may date back to when the house was built in 1932, or at least before we moved here in 1971. This simply counts the units we use, no fancy stuff, but when the P.V. panels are working the meter runs backwards and thus knocks off units from our total. I have told the electricity company about this, and it is visible when they come occasionally to check our meter readings, but they have never commented on it. They do keep on trying to get us to instal a smart meter ‘to help us save electricity and keep our bills down’ but for some reason we have not succumbed to persuasion.
We have also had the wall cavities filled and loft insulation fitted. All our rainwater off the roof is saved and run into the pond to keep it topped up. Maybe if we had bigger storage tanks for winter rainwater, when there is a surplus, we could save more, but it would be difficult to find room for the huge tanks at the side of our house.
Our condensing boiler has recently developed a fault and our gas engineer says it’s not worth spending £300 + labour on the parts to mend it. It has been very reliable but is now 13 years old, over its expected life of 10 years, so like you, Rick, we are wondering about heat pumps etc. The problem is that we would need a totally new system, needing the removal of all our radiators and substitution with a different sort of bigger ones, which would be massively more expensive than buying a replacement Worcester boiler, the latest improved model of which is due to come out in a couple of months’s time.
 
Thanks for the link Margaid. I'm going to contact them for some general advice and maybe some formulas to help with the sums.
Hmmm. Its a shame it seems like a heat pump would need some major changes to work well, and use electricity to run which is at least 3 times the price of gas from the grid so then PVs with batteries... or running the old meter backwards :D that's so cool!
What I'm thinking is that although electricity on economy 7 wont be as cheap as gas, the control systems for hot water storage tanks should be a lot more 'smart' than they ever were. With solar collectors for a hot water tank in the loft. And insulation, the boring but essential bit! of course.
I really like the idea of the storage tanks in the cellar with pipework, dials, a Raspberry Pi running the show - Something really steampunk! :)
 
If you have a cellar, of course!
In an old house, it’s a compromise between doing one’s best for the planet, at enormous cost to retrofit new technologies, or just doing what is reasonably possible in a less than ideal situation. It would be lovely to have a hand in designing a new house to incorporate all these improvements literally from the ground up!
After nearly fifty years of work on our garden, I really don’t feel like excavating huge holes in the back garden to instal a heat pump and all its pipework, tearing out the present heating system, having up the floorboards to instal underfloor heating, and totally redecorating every room. We’ve done all the simpler things anyone can undertake, and so I feel we’ll just have to go on trying to recycle where possible, and reduce consumption of other things.
 
Microbore systems are perfect for condensation boilers Margaid. The reason is the radiators are oversized to compensate and the return temperature is below the 53C required for condensation (normally returns are over 60C), so you do actually get the savings they claim. No other systems work other than for startup. Also microbore is far less water to heat. I took our system from 150L to just 42L and created the best system I had ever seen, perfect for a condensation boiler update- bet the new owners don't realise that (so happy to have got rid of that place).

What is often overlooked is the payback period for the investment. Nothing I have seen so far works. You may be 'greener' but you will pay dearly for it. Things you buy not only fail to meet the claims but cost a fortune to maintain.

Talk to different engineer if necessary Marigold. Keep your old boiler going if you can as you will never recover the cost of replacement and never achieve the savings claimed. If you can get spare parts get them.

Rick. I was given a formula for salesman claims- divide by ten. It has always proved correct.
 
But there are advantages to updating an old boiler, Chris. After 13 years, the newest Worcester boiler will have fewer emissions and be more economical than our old one, good though it was in its time. So probably better than flogging on with an old one which emits more. Also, we really need to be confident that we shan’t have heating problems in winter, for health and safety reasons, and also because any savings on not investing in a new boiler would soon be used up in paying an engineer to come and mend it!
 
It isn't simply a case of floorboards up Marigold, generally the floor level is raised about 15mm. I have some type of concrete floor - it may be beam and block under the screed so fitting underfloor heating, which I would really like to have, would be a really major undertaking. HAving lived on a building site for 8 years I don't fancy that again!

My Worcester Heatslave oil fired boiler is 22 years old. It's not a condensing boiler. While I can still get parts I will keep it going although I am aware that the emissions are probably high. The house had not been lived in for 5 years when I bought it and although the heating was apparently run to stop things freezing, in the first two years I replaced the expansion tank, the pump, the oilburner and the motor for the changeover valve as some things "stuck" when the boiler usage went up. Typically all these things happened in a cold spell when the idea of waiting for a new boiler with no heating or hot water did NOT appeal.

Three of the five houses are running on their original boilers. One occupant changed his because he knew someone working at the factory who was able to give him a VERY good deal, and the other neighbour changed his because he could save on oil. But the amount he saves means it will take about 10 years for payback.
When I do decide to change it I have no doubt there will be much more efficient boilers available. I've resisted the blandishments of salesmen trying to get me to change to LPG!
 
chrismahon said:
Rick. I was given a formula for salesman claims- divide by ten. It has always proved correct.
Click to expand...

Yes... I dont mind paying a consultant for good design and advice - that's fair, but I'm nervous about approaching any provider/installer without knowing enough to sort the good from the cherry picked glossy sales pitch - and by that time I could do it myself (with the help of an electrician for the supply side, of course.) The rest is plumbing, pumps and a bit of basic Python (which I know is not for everyone but for my sins...)

If we do end up getting a new combi (Id rather not) then it will have to be able to take a pre-heated feed for hot water from the tap because this one isn't able to. Hot water from the tap consumes a crazy amount of energy. I calculated what would be needed to do the same as the gas boiler at the shower and it was 28kwh (about 160 amps at the fuse.) Obviously, as soon as you have storage then the peak isn't so instantaneous and abrupt but still... it really makes you think what is happing with a running hot tap.

I think it might be possible to blow heated air through ducts from the cellar for the two main downstairs rooms. Draft recipe: two 150L tanks, a van radiator and fan. 4kwh waste heat capacity after climbing, fully laden in a heatwave, over a mountain sounds about right... maybe. The modern storage rads have a fan blowing out at floor level rather than just convecting up the wall which sounds much faster and better at warming a room only when needed. They will even shut down when the window/door is open rather than trying to do the impossible.
Anyway - this boiler is hanging on by a whisker so something has to give!
 
Condensing boilers on their own won't give much of a saving unless the rest of the system is designed appropriately. I appreciate though that for most the driving force for replacement will be spare parts availability and labour costs.

The limitation we have here is spare parts. There are only a few bits I can get for this French 22 year old boiler. When we got here the owner was getting oil deliveries every month and complained of being cold. Whilst the boiler was serviced every year the rest of the system hadn't been touched. The expansion vessel had lost its pressure and was installed incorrectly so it couldn't be simply re-inflated. All the convector emitters (they are not UK style steel radiators), which run at a much lower temperature, were blocked with 22 years of dust so basically the boiler was running flat out but the heat couldn't be distributed. All this has been rectified. It is always worth replacing the jet- recommended annually, but every 5000 Litres I think. Also worth doing is making sure the emissions are correct and that needs an engineer with a gas analyser- the boiler burner can be adjusted or tuned to get the best out of it and just that can save a lot of oil. It might have been set incorrectly in the beginning- they used to simply look at the flue for smoke! Clean the convector ducts on the radiators (The Range sells the brushes)- you will get the same heat for lower temperature and improve boiler efficiency. Honeywell do an intelligent thermostat which predicts heat loss and fires the boiler up in advance but to a lower temperature- we have one.

The French Government has decided to stop people replacing oil boilers, so when our combi-boiler (wouldn't have been my choice) goes we are facing a huge bill and a headache. The heating will have to go onto wood pellets (lots of plastic bags for recycling) and the hot water to electric, which means a fair bit of alteration. There is the option for solar pre-heating of the water at some stage, so the storage tank would need to suit that. Costed that out though and the payback is 30 years, so basically never. We only use the central heating for 3 months of the year, but log burners are not a realistic option in a 'long house' as they are known. Electric heating is impossible as our supply is single phase (usually three phase) and limited to 6KW.
 
Completely non scientific and probably not very useful, but I have 2 anecdotal observations about hot air. We lived in a 1920s semi with a cellar for years and it was the warmest house I have ever lived in. Partly because the rads were plentiful and big enough, but mostly because the gas boiler was in the cellar. We had exposed boards, which were the ceiling to the cellar and the floor to the ground floor (ie no cavity), just sanded and sealed, with the worst of the gaps packed with folded cardboard. The ground floor was always warm, and the floor was also warm, particularly in the room directly above the boiler. The boiler was an old Potterton, at least 25 years old when we moved. The plumber said 'they don't make them like this anymore'! back in 2006.

Here in Portugal central heating is unusual, its only found in new builds, it is common to have a small open fire in the corner of the room, or a recuperador which is an insert wood burner. You have grills in the chimney breast and the idea is that the heat goes up the flue and out of the grills. If you stand at the grill on the ground floor where the woodburner is, then you feel some warm air coming out, although not loads, however, upstairs you don't. We have a large room here, where all life takes place, so the burner is pretty big as well, 18kW I think. We have electric fan assists on the burner, and they do seem to work, blowing air out of vents at ground level. In all my other houses I have had small freestanding air-driven fans to help waft the warmth around, and again, I think they do work. A bit off topic I know, but I thought I'd contribute. We have a gas combi boiler here, but its not much good. I am now adept at washing in lukewarm water because it takes so long to run hot, and I am so mindful of not wasting water. I also turn the shower off between soapings and rinsings, I think I am pretty economical there, but in the winter and certainly before we had heating in the bathroom, I have been known to run the shower without me in it, to get the cubicle all hot and steamy, so that probably negates it!

Portugal has long had days on which all its energy comes from renewables - mostly wind, with perhaps less solar than you might think. Its a very hilly country, with lots of high ridges, and there must be thousands of turbines. We certainly have them marching across the tops of high hills here, I find them very comforting.

Edited to add - we also have a new pellet burner as its much cleaner than the woodburner, and a couple of years ago I got some sort of mild pneumonia making me very susceptible to particulate in the air. We really notice the difference in particulate, the amount of ash produced is miniscule, and the official efficiency is much higher than the wood burner. Its not cheap to run (its a dry system, ie stand alone and not connected to rads), and there is little residual heat, as soon as you turn it off the heat dies, but has the huge advantage of being programmable, giving quick heat, and you can turn it off if you are going out. We tend it use it in Spring/Autumn for a few hours in the evening. We live in the midst of acres and acres of forest, wood is the key industry here, and we have 3 pellet factories within a 15 mile radius, so we feel we are contributing to local industry, even if its not the cleanest of fuels.
 
If your in the right situation and the wood pellets are from sustainable plantations then it sounds absolutely ideal. I agree with the bag thing Chris - around here you can sell heavy weight PE bags to the recycling plant but they have to be clean and delivered by the tonne minimum. I guess big industry and farming have an arrangement but domestic stuff, builders bags etc. - there is not much choice but to end up in landfill. The only thing going on on the PE front for householders is carrier bags collected by the supermarket.
 
There are 17 small power stations in France running on 'recycled' plastic Rick, so the bags won't go into landfill but will be burned for electricity. They are after all an oil-based product. No idea how they 'scrub' the emissions though?
 
You must log in or register to reply here.

Latest posts

Back
Top