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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorJeff B
    • CommentTimeAug 25th 2021
     
    +1

    Contemplating reverting to oil boiler from wood pellets but not too late to be persuaded to reconsider ASHP! Cost is the major deciding factor.
    • CommentAuthorrevor
    • CommentTimeAug 26th 2021
     
    Posted By: Jeff B+1

    Contemplating reverting to oil boiler from wood pellets but not too late to be persuaded to reconsider ASHP! Cost is the major deciding factor.


    I think there is a point at one end where HP will cost an awful amount to run v.s a point where a HP would be overkill. When we gutted our place and rebuilt we had a dilemma of what we should have as the heat source and considered all the usual options. We decided to design the house so it would need very little heat to maintain a comfortable temperature so we concentrated on V high levels of insulation, solar gain with glazing on the south and west elevations but which we could isolate from the rest of the house if it got too much, kept much of the original stone building to act as thermal mass, added solar thermal on the roof with thermal store UFH and MVHR but with DG .Built aiming for zero leakage and zero cold bridging. In the end we decided that the HP would be overkill as we reckoned we would not need much heat. Unsure we went with a LPG boiler with gas in bottles to see how it panned out. Last year we used just shy of £300 of gas (320sqM house) and if we had a COP3 HP we would have saved about £90 but not have the immediacy of heat a gas boiler gives. So the cost effectiveness I reckon of any of the options depends on the state of the level of insulation draughtproofing and elimination of colds spots. Without these, think HP will be too expensive to run and a perfect PH would not justify one by my reckoning. If possible best spend £10K on a fabric first approach that a HP.
    • CommentAuthorJeff B
    • CommentTimeAug 26th 2021
     
    <blockquote><cite>Posted By: revor</cite><blockquote><cite>Posted By: Jeff B</cite>+1

    If possible best spend £10K on a fabric first approach that a HP.</blockquote>

    That is my one big regret - when we bought this place 15 years ago we wanted to be "green" and we were pioneers in a way by installing a wood pellet boiler to replace the existing oil fired boiler, well before RHI was even dreamed of. With hindsight what we should have done was to install better insulation, better windows and draught-proofing before even thinking about changing the boiler. We have done all those things now in addition to having the wood pellet boiler and have reduced the heating requirement from 3000 litres of oil p.a. to 3000kg of wood pellets p.a., which is approx half in terms of kWh. A further regret I have is that we got rid of the original boiler when RHI came along and bought a "better" one which apparently required far less hands-on attention but in reality is no different to the first one! Hence regrettably considering going back to oil.
    • CommentAuthorrevor
    • CommentTimeAug 27th 2021
     
    Posted By: Jeff BHence regrettably considering going back to oil.


    We were on oil originally and it is the cheapest fuel around here but many oil tanks around where I live were subject to thefts of oil by drilling holes in the tank to get at it and leaving a mess in the process so that was out plus it is dirtier than gas. We also considered a pellet boiler but was not convinced about the operation of it and in the future being able to load it, was finally discounted when a local builders merchant had one in their branch and they complained like mad that it was always breaking down. So it was gas or HP. At the time I was in an exchange with the Scottish passive house company think that was the name (think no longer in existence).They told me that they built PH for the local authority and fitted quite small gas boilers as that was the most economical way of providing on demand heat and hot water with HP being an unnecessary overkill so that is how we got there in the end. Best choice is no boiler at all off course and some PH do manage it?
    • CommentAuthorJeff B
    • CommentTimeAug 28th 2021
     
    Thankfully we do not have the problem of oil theft where we are. I think this is usually confined to really remote properties or farmhouses but even then is very rare. Whilst oil may be cheap at the moment I do wonder what will happen in the near future (leaving aside conflicts in the Middle East), such as increased fuel tax to "encourage " people to get away from fossil fuels. Time will tell.

    You were very wise not to go down the wood pellet route. In fairness my pellet boiler has been ok but it requires regular hands-on maintenance to keep it that way. If neglected the burner pot would soon clog up with clinker which blocks the air holes and if left will set like epoxy cement! The ash plate mechanism requires regular lubrication otherwise I understand it will eventually seize up and fracture. Again I can cope with all that but my wife is concerned that if anything happened to me (I'll be 75 soon!) then she would not be able to manage with it and finding anyone locally who has the first clue of how to service it would be a miracle!
    • CommentAuthorrevor
    • CommentTimeAug 28th 2021
     
    For anyone interested in quite some coverage of Home heating and storage, in last couple of weeks 5 episodes of Home energy videos have appeared on Fully charged

    https://www.youtube.com/channel/UCzz4CoEgSgWNs9ZAvRMhW2A

    The link takes you to the list of videos.
    • CommentAuthortopher
    • CommentTimeAug 30th 2021
     
    Work starts tomorrow = 31 August and is estimated to take 5 days. Fortunately my Honeywell Evohome controller will control the house heating. I cant use it for Hot-water - that will have to use the Daikin system.

    I can get green electricity from 12.30 am to 4.30 am at 5 GBP pence per kWh (6 euro cents or 6.9 US cents). So the hot water heating will be cheap. I will have to study what I can do in daytime when it will cost a lot more.
  1.  
    Hi Topher, did Daikin insist you use one of their accredited installers, or did you go with an independent? How did you find your installer?
    • CommentAuthortopher
    • CommentTimeSep 2nd 2021 edited
     
    Hi, WillinAberdeen,

    My neighbour was searching for installers and told me about the company I am using.

    He is Gov and Daikin approved.

    I would recommend him, but he is based in Fleet south of the UK.
    • CommentAuthortopher
    • CommentTimeSep 2nd 2021 edited
     
    Day 1 Report.

    Daikin stuff was supposed to arrive today. It did not. Four men arrived - the company owner a plumber, another plumber, an apprentice, and a ground worker who made the plinth for the external unit.

    They started on ripping out all the old plumbing, hot water cylinder, loads of pipework, the gas boiler, and much else. It is a big upheaval to the house.



    Picture 1 - start of pile of rubbish, it gets much bigger.

    Picture 2 - mould for plinth, will have drain connected to rainwater soak-away.
      IMG_4159.jpeg
      IMG_4158.jpeg
    • CommentAuthortopher
    • CommentTimeSep 2nd 2021
     
    How do I set this system to alert me when someone responds?
    •  
      CommentAuthordjh
    • CommentTimeSep 2nd 2021
     
    Posted By: topherHow do I set this system to alert me when someone responds?

    You can't. You have to look. What I do is just stay logged in and visit the All Discussions page, which I have bookmarked. That shows which topics have new postings.
    • CommentAuthortopher
    • CommentTimeSep 3rd 2021 edited
     
    Day 2, 3, & 4 Report

    First some things you discover no matter how much planning you have done.

    Making good - I believe that the plumbing trade normally leave holes if they have removed old pipes, for example the hole left by the boiler flue, and smaller holes where pipes go through plasterboard. These have to be ultimately made good, but not by plumbers.

    Household upheaval - it depends on your attitude to life, but the water and the electricity will go off a number of times, in some cases for quite a while. This can be disruptive.

    On day 4 the electrician arrived, and as I write, we are hoping to put the system on this evening. Full set up and commissioning will be done tomorrow. The heat pump will not make its very first start unless the water is above 20 degrees, so it will have to be pre heated. The hydro box has an immersion heater.

    Today (day 4) a significant problem arose. The 250 litre Daikin HW cylinder has to go in the loft; the house has ground and first floor. The cold feed is a 15 mm pipe which works fine until a cold tap is opened, then the flow from the hot falls to a dribble. As I write the 15 mm feed is being increased to 22 mm from the incoming supply all the way to the tank. When we tested it there was a significant improvement. The hot flow reduced when the cold was opened, but not to a dribble. I will see how much of a problem this is. A possible solution is an "accumulator". This is a 300 litre cylinder of water with a membrane pressurised with air. It accumulates 300 litres of water and supplies it at full mains pressure.

    The system design for Daikin is very thoughtful. For example, if the outside fan unit ices up and needs to be defrosted, the heat pump reverses and cools the circulating water and heats the outside air/water heat exchanger to melt the ice. When the ice has gone, it reverts to normal operation. But consider if nothing in the house is calling for heat - the motorised valve will be closed and the small amount of water in the pipes will not be enough. So Daikin specify a 20 litre vessel in line with the pipe. This provides enough water for the defrost. Unfortunately, in normal use, this vessel is hot with circulating water and is a heat loss in my garage. I will have to consider insulating it.

    Picture-1. Plinth prepared ready to take fan/coil unit. Drain provided to take water when unit ices up in cool and humid weather, and for condensation that happens in normal use, like today.

    Picture-2. Outside fan coil unit mounted on vibration mounts.

    Picture-3. Huge amount of control electronics inside fan/coil unit. There is a similar amount inside the hydro box too.

    Picture-4. HW cylinder in the loft. .
      Pic_1.jpeg
      Pic_2.jpeg
      Pic_3.jpeg
      Pic_4.jpeg
    • CommentAuthorbhommels
    • CommentTimeSep 3rd 2021
     
    @topher, many thanks for posting text & pictures. Very interesting to see the nitty gritty of ASHP installation. Hope all goes well from here!
    •  
      CommentAuthordjh
    • CommentTimeSep 3rd 2021
     
    It appears your hot water tank and associated pipework are above the loft insulation, and so in a cold area. I'll be interested to see/know how much insulation is eventually fitted to the tank and to the pipework.
    • CommentAuthorrevor
    • CommentTimeSep 3rd 2021
     
    Posted By: topherPicture-3. Huge amount of control electronics inside fan/coil unit. There is a similar amount inside the hydro box too.


    One can see just how much more complicated HP is compared to a Gas boiler resulting in a big contribution to the cost differential.
    • CommentAuthortopher
    • CommentTimeSep 4th 2021 edited
     
    Hi djh,

    Yes you are dead right, very cold in winter, and boiling hot in summer.

    I had asked for the lagging to be left off for my lesson on what everything does - there are loads of safety devices. I am sure that there is loads of frost protection too.


    I hope I will remember to take a pic when to lagging is installed.
    • CommentAuthorowlman
    • CommentTimeSep 4th 2021 edited
     
    Hi topher,
    I don't want to rain on your parade but for your own peace of mind double check the flow and return pipework sizes and correlate it against pipe run length, flow rates etc.. Those pipes look like either 22 or 28mm.
    If you have opted for the 14kW model and the run is fairly long and depending on the design flow rate they may need to be 35mm. It varies of course, one manufacturer to another and model spec., I'm told it can be a source of future underperformance. If the results are borderline it may be better to go up a size, check the small print.
    The knock on effect from a plumbing point of view can be significant and fitters do what fitters do, and sometimes make their job easier, and cheaper, for themselves. Joining 35mm pipes is more onerous as is the final very thick bundle of pipe + good quality insulation.
    NB apropos pipe insulation; For best results go with thick wall neoprene, Armaflex or Kaiflex. I used a combination of 19 and 25mm wall thickness. If pipework losses are too great you may find the final delivered temperatures are not what expected.
    • CommentAuthortopher
    • CommentTimeSep 5th 2021
     
    Hi owlman,

    I think it will be OK. The pipes are 28 mm and the fittings on the external fan unit, the internal hydro box, and the HW cylinder are all 28 mm. Everything is in 28 mm. The installer is Daikin approved and very competent, mine is not his first installation.

    I am also reassured by a clever trick from Daikin. They provide a special electrical cable which must be used between the hydro box (a pile of logic, pump, and aux heaters). The cable is 10 meters long - this is to prevent an installer putting the two units > 10 m apart.

    I know it's summertime, but it works.
  2.  
    Hi Topher, did you get the Daikin indoor 'hydro box' (containing the various CH system components), or did your installer fit those piece-meal?

    Is it running yet?!
    • CommentAuthorSteveZ
    • CommentTimeSep 8th 2021
     
    Hi Topher, thanks for a very interesting project.

    We are running a Grant combi-boiler on oil and, at some time in the future, I will have to find a replacement system, and it will probably be a Heat Pump.

    Did you look at the Sunamp phase change heat battery when you were deciding on your new DHW system? When we change over we will need a source of DHW and at the moment I can only see the advantages in the heat battery idea, over the larger and more complex conventional cylinder.

    This replacement could be pushed into the future as there is a trial going on in the South West (and probably elsewhere) of a kerosene/diesel substitute made from vegetable oils called HVO or Hydrotreated Vegetable Oil, which may provide a medium term more eco way of continuing to use the Grant until it dies of old age. It is claimed to produce 90% less pollution the kerosene, although exactly what that is based on I don't know.

    Thanks again for the story and pictures
    • CommentAuthortopher
    • CommentTimeSep 8th 2021 edited
     
    Day 5 Final Report.

    The installation work is complete. There are some things that will be done later. My neighbour has been very lucky. He will have the same product installed by the same company in early October. He has been able to see all the errors and omissions I have made. Below are my ideas of the most significant learning points that come from the 5 day experience

    I chose an excellent installer. We had between 3 and 4 people every day and they all worked really hard. I had decided to change the poor skirting board heat in the lounge to two conventional radiators. I expected the pipes to be run externally along the standard skirting board. No, they wanted all the pipe work to be under floor with vertical pipes to be run to each rad. Amazingly they cut an access in the suspended floor and crawled underneath - removing old pipe, jointing, fitting tees, and insulating everything. What dedication!

    I have mentioned it before, your house will be occupied by a small army. We found it a big disruption. It is over now, and I am sure it will have been worth it.

    Daikin don't use the standard terms that I understand. For example 'tank' is hot water cylinder. I also find the control panel very complicated and not intuitive. But I will learn.

    Carefully check the position of the HW cylinder. Mine went in the loft and as a result the flow and pressure of hot and cold water is very poor. I am in the process of installing an accumulator to solve the problem. With hindsight this should have been installed during the installation phase

    Daikin's admin is very poor, three items were missing in the original delivery. The wi fi unit that I need to use the app, has finally arrived, but there is no one to install it. I might try to do it

    We used the excellent Evohome system for heating controls. Its HW control is incompatible with Daikin, but the heating control (boiler relay) can be used. I very much like the Evohome because it calculates the turn on time with room insulation behaviour and external temperature for each room. I found that my old boiler controller, which worked fine with the old gas boiler was no good. I had to buy a new one which was compatible with heat pump. Honeywell have an excellent customer support service. I found I needed an up date to the controller for heat pumps. They down loaded it in 30 minutes. I have installed it an am waiting for a slightly cooler period to try it.

    It appears that plumbers dont do 'making good'. All the old holes in plasterboard and other things need to be filled and sorted out afterwards. Look at pic 1 to see what I mean.

    The water has a taste of flux, I hope it is not bad for us, and expect it will go away with time.

    I live near the sea and treatment against salt air for the external fan coil unit was done by Blygold.

    If you have questions I am happy to have a phone call, we can exchange telephone numbers by the 'wisper' process.

    Picture 1. Hydro box partially installed in the garage. Note 'volumiser' which is 20 litre supply of water for heat pump to use when de-icing. I will have to insulate it.

    Picture 2. Honeywell Evohome controller. It needed an online firmware update

    Picture 3. Anti-Corrosion treatment.
      IMG_4195.jpeg
      IMG_4197.jpeg
      IMG_4173.jpeg
    • CommentAuthorJeff B
    • CommentTimeSep 8th 2021
     
    Posted By: SteveZHi Topher, thanks for a very interesting project.

    We are running a Grant combi-boiler on oil and, at some time in the future, I will have to find a replacement system, and it will probably be a Heat Pump.

    Did you look at the Sunamp phase change heat battery when you were deciding on your new DHW system? When we change over we will need a source of DHW and at the moment I can only see the advantages in the heat battery idea, over the larger and more complex conventional cylinder.

    This replacement could be pushed into the future as there is a trial going on in the South West (and probably elsewhere) of a kerosene/diesel substitute made from vegetable oils called HVO or Hydrotreated Vegetable Oil, which may provide a medium term more eco way of continuing to use the Grant until it dies of old age. It is claimed to produce 90% less pollution the kerosene, although exactly what that is based on I don't know.

    Thanks again for the story and pictures


    SteveZ - coincidentally only yesterday I was talking to a chap who works for a local heating oil delivery company and he brought up the very subject of this HVO substitute. I had not heard of this before. A quick search on Google brought up this article about a trial in Scotland:

    https://www.jamesdbilsland.com/blog/fthe-first-trials-of-using-hvo-renewable-fuels-as-an-alternative-to-home-heating-oil-in-scotland

    This is of particular interest to me as I am in the process of changing to heating with oil from heating with biomass (long story!). Where we are in west Wales practically every man and his brother uses kerosene for heating and I suspect very few properties are ok for ASHP. We are probably borderline thanks to pretty extensive IWI.

    We are getting a Grant system boiler (not a combi) as we already have a DHW tank with solar coil. This provides all our DHW from May to September, with only an occasional boost from the immersion heater on cooler/cloudier days.
    • CommentAuthorJeff B
    • CommentTimeSep 8th 2021
     
    Topher - thanks for the final report - quite an effort there but very useful for others contemplating ASHP!
    • CommentAuthortopher
    • CommentTimeSep 8th 2021 edited
     
    <blockquote><cite>Posted By: WillInAberdeen</cite>Hi Topher, did you get the Daikin indoor 'hydro box' (containing the various CH system components), or did your installer fit those piece-meal?

    Is it running yet?!</blockquote>

    Will,

    The installer did everything, hydro box included. Yes it is running. My installer got everything from Daikin. They supply almost everything except the expensive copper pipe and cables !
    • CommentAuthortopher
    • CommentTimeSep 8th 2021
     
    Steve,

    No, I was unaware of the Sunamp product. Oil and gas boilers are said to produce 15% of the UK CO2. If a heat pump produces zero CO2, do you know how much HVO produces?

    Thanks for your kind words.
    <blockquote><cite>Posted By: SteveZ</cite>Hi Topher, thanks for a very interesting project.

    We are running a Grant combi-boiler on oil and, at some time in the future, I will have to find a replacement system, and it will probably be a Heat Pump.

    Did you look at the Sunamp phase change heat battery when you were deciding on your new DHW system? When we change over we will need a source of DHW and at the moment I can only see the advantages in the heat battery idea, over the larger and more complex conventional cylinder.

    This replacement could be pushed into the future as there is a trial going on in the South West (and probably elsewhere) of a kerosene/diesel substitute made from vegetable oils called HVO or Hydrotreated Vegetable Oil, which may provide a medium term more eco way of continuing to use the Grant until it dies of old age. It is claimed to produce 90% less pollution the kerosene, although exactly what that is based on I don't know.

    Thanks again for the story and pictures</blockquote>
    • CommentAuthorJeff B
    • CommentTimeSep 8th 2021
     
    Topher - re HVO. If you follow the link I included in my post, there is a further link to a YouTube video. In this it is claimed that HVO emits 90% less CO2 than kerosene.
    •  
      CommentAuthordjh
    • CommentTimeSep 8th 2021
     
    I wouldn't expect a plumber to make good. It's a different skill. Perhaps some 'bathroom fitters' and suchlike can do a bit of plumbing and a bit of tiling and decorating, and maybe a bit of carpentry but that's a multi-skilled specialist. OTOH I'd expect a serious plumber to do a better job of the plumbing itself. Sadly not always the case. :cry:
    • CommentAuthortopher
    • CommentTimeSep 8th 2021
     
    Hi djh,

    OK, I now know that, but I did not when I started, so that is why I highlighted the point to advise others who might have the same expectation as I did.

    On the skill of the plumbers - I think they were excellent.
  3.  
    Topher, thank you, this is great intel.

    What's your impression of how noisy it is when running?

    How did the electrical side of things go - any issues running the main cable to the heat pump or with RCDs tripping? Is the main cable in the picture of the hydrobox or does it go directly to the outside unit?

    Much appreciated!
   
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