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Dual system (oil-fired and solid fuel) advice needed

  • 30-09-2008 7:49pm
    #1
    Registered Users Posts: 2,126 ✭✭✭Psychedelic


    My parents have a standard oil-fired central heating system and are looking at adding a solid fuel system to this. I was just wondering would anyone here have any diagrams or links to information about how a dual system like this should be set up?
    Post edited by Jonathan on


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Comments

  • Registered Users Posts: 680 ✭✭✭copper12




  • Posts: 0 Mabel Teeny Oasis


    Here is how I connected in my solar buffer tank, you could do something similar with a solid fuel boiler in place of the tank.

    The principle is that the return always passes through the tank (SF Boiler) if the output temperature is below a preset level it also passed through the boiler, if above, the boiler is switched out.

    heating_pipes.JPG

    A very simplified drawing, there are a couple of aav's in the final installation and the system in unpressurised!

    [img]http://dolanbaker.info/images/stories/boards/electrics v41.JPG[/img]


  • Registered Users Posts: 324 ✭✭Slates


    My parents have a standard oil-fired central heating system and are looking at adding a solid fuel system to this. I was just wondering would anyone here have any diagrams or links to information about how a dual system like this should be set up?
    Check out the Systemlink website


  • Registered Users Posts: 2,126 ✭✭✭Psychedelic


    thanks all, much appreciated.


  • Registered Users Posts: 680 ✭✭✭copper12


    Dolan baker
    Why are you heating the (SF boiler ) with the return from the oil boiler
    Could you not bypass the solar buffer tank


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  • Posts: 0 Mabel Teeny Oasis


    copper12 wrote: »
    Dolan baker
    Why are you heating the (SF boiler ) with the return from the oil boiler
    Could you not bypass the solar buffer tank

    Please note these drawings are for my solar system, I just suggested that they could be ammended for a SF boiler!

    My intention is to pre-heat the water via the solar tank, most of the time the water temperature in this tank will be below 65C (except in "summer") so that the return temperature to the boiler will usually be raised by solar energy before bringing up to 75C for the main thermal store in the house.

    If we get a few sunny days in the summer, then the bypass pump will kick in and supply the tank directly with "free" energy.


  • Registered Users Posts: 680 ✭✭✭copper12


    man after my own hart
    I did not realize you were using buffer tank along with a solar tank


  • Posts: 0 Mabel Teeny Oasis


    copper12 wrote: »
    man after my own hart
    I did not realize you were using buffer tank along with a solar tank

    Yes, it's just not on the drawings. oops :o


  • Closed Accounts Posts: 422 ✭✭ Mya Brave Morning


    Sorry if i'm hijacking the thread but an elderly relative has had oil fired central heating installed. The house already has a stanley cooker with a back boiler which heats the water. Would it be a big job to link the back boiler in so it would heat the radiators. If its possible without ripping the house apart how much would a job like this cost.


  • Registered Users Posts: 1,569 ✭✭✭Builderfromhell


    It's normally possible. However, you really need a plumber to look at it to determine the complexity of routing pipes to it etc.


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  • Registered Users Posts: 680 ✭✭✭copper12


    If the oil central heating also heats the hot water tank. then it’s most likely that there is a dual coil cylinder already installed. if this is not the case then it may be a direct cylinder fitted to the Stanley ?.
    If there is a dual coil cylinder fitted; then it wont be to big a job to combine the Stanley cooker to the heating system


  • Registered Users Posts: 153 ✭✭rayh


    Psychedelic and Sussandsurf, before you get too involved in valves and circuits, could I suggest that you step outside the circle and look again at what you are proposing.
    If you accept that we as a society have just come through a period of cheap fossil fuel energy and are about to experience our migration from these sources coupled with the challenges of its consequent effects on our environment and climate.
    The actual timeframe for this transition is not clear, but we can be certain of its inevitability.
    This transition will require us to make some significant changes to how we manage the shelter process for which we have two options;
    1. Make the changes in one single change.
    2. Make the changes incrementally.
    As you both appear to have adapted the incremental option, can I suggest that you now consider your next change and only then should you get down to the valves and circuits business.


  • Registered Users Posts: 45,680 ✭✭✭✭muffler


    rayh wrote: »
    As you both appear to have adapted the incremental option, can I suggest that you now consider your next change and only then should you get down to the valves and circuits business.
    What exactly are you talking about. Im lost at this stage.

    Both posts and posters are in relation to elderly people wishing to get a little extra warmth in their homes and not about looking for info on how to shag a tree live in a passive house.


  • Registered Users Posts: 45,680 ✭✭✭✭muffler


    copper12 wrote: »
    Psychedelic and Sussandsurf, not sure what you meant, was this some kind of a insult? :confused:
    If it was; could you explain it a little better.
    Should we kill small furry animals and wear there skins to keep warm.
    Or could we use bio diesel as the fuel for the oil central heating and wood for the Stanley cooker
    Id be interested in hearing your explanation for those comments.


  • Registered Users Posts: 153 ✭✭rayh


    Sorry if I have offended anybody, but I am satisfied that the reactions are typical of our society which is in total denial of the reality of our current energy supplies, environmental derogation and the consequent directions we will have to be forced to take into the future.
    The reality is that the fossil fuels are in decline from here on and that we have seen the end of cheap energy fuels which will require us to massively reduce our energy requirement and move to carbon free energy sources.
    On of the main issues to emerge from a cheap energy regime has been efficiency and if I understand that both of these cases refer to an elderly circumstances, can I suggest that the first port of call is insulation or the conservation of the energy source rather that exploring a more effective method of applying energy to the shelter process.


  • Posts: 0 Mabel Teeny Oasis


    rayh wrote: »
    Sorry if I have offended anybody, but I am satisfied that the reactions are typical of our society which is in total denial of the reality of our current energy supplies, environmental derogation and the consequent directions we will have to be forced to take into the future.
    The reality is that the fossil fuels are in decline from here on and that we have seen the end of cheap energy fuels which will require us to massively reduce our energy requirement and move to carbon free energy sources.
    On of the main issues to emerge from a cheap energy regime has been efficiency and if I understand that both of these cases refer to an elderly circumstances, can I suggest that the first port of call is insulation or the conservation of the energy source rather that exploring a more effective method of applying energy to the shelter process.

    Fair enough, in the grand scheme of things.

    But the OP was specificaly asking how to improve the existing system in an elderly relatives house in the short term only.


  • Registered Users Posts: 18 Kevin007


    My parents have a standard oil-fired central heating system and are looking at adding a solid fuel system to this. I was just wondering would anyone here have any diagrams or links to information about how a dual system like this should be set up?
    Fitting an additional SF Boiler to an Oil system is not the best way to go as the efficiency of an badly maintained OFCH ( Oil Fired Central Heating ) system can be 65% compared to an efficiency of 40% with a SF System. The capital cost of fitting a SF Boiler etc. can be excessive relative to the Heating gain (nil) Your parents would be better served in improving the efficiency of their OFCH system rather than waste their money on very expensive SF equipment. If they have access to Natural Gas, then a High Performance Gas Condensing Boiler would be a better option


  • Registered Users Posts: 45,680 ✭✭✭✭muffler


    Thanks for bringing this back on topic Kevin007.

    rayh perhaps its better for everyone, especially yourself, if you post in the Green Issues forum if you are intent on going on rants and derailing the thread.


  • Registered Users Posts: 680 ✭✭✭copper12


    I have deleted my last post
    rayh I owe you an apology
    Keven007
    Fitting an additional SF Boiler to an Oil system is not the best way to go as the efficiency of an badly maintained OFCH ( Oil Fired Central Heating ) system can be 65% Your parents would be better served in improving the efficiency of their OFCH system.
    I would agree with you on this; if the only control for the heating system; is an; on’ off ‘switch.
    A programmer’ or a timer’ to control set periods; nothing fancy just ON/OFF/CLOCK would do. A room stat; cylinder stat; and maybe some Thermostatic Radiator valves; this option’ would not be to expensive; and should pay for them selves in a couple of years.
    compared to an efficiency of 40% with a SF System.
    Depends on the SF system. If it were a Back boiler; using coal’ then I would agree with you however there are some SF systems that are very efficient; and also very expensive.
    If they have access to Natural Gas, then a High Performance Gas Condensing Boiler would be a better option.
    provided it is installed properly’ and will operate in condensing mode; when it is in use; not an easy thing to do’ most of the boilers I come across’ seldom operate in condensing mode; and if they do’ then it only for short periods.


  • Registered Users Posts: 18 Kevin007


    Hi again
    Manufacturers and retailers of all boilers fail to tell the public that the efficiency of combustion boilers is measured by the uptake of heat returning to the boiler at 0deg.C and not the real temperature of 60deg.C This gives a completely incorrect and unachievable efficiency and is comparable to a car being rated on its fuel comsumption going DOWN a hiil and not up. Secondly The moisture content of wood fuel is never below 10% and b4 you start to get any heat from your fuel this moisture has to be evaporated and the energy this takes ( Latent Heat of Evaporation ) should be deducted from the outputs that are quoted. Thirdly If a solid fuel appliance is not cleaned thoroughly at least once a week, a 3mm deposit of soot on the walls of the boiler reduces the transfer of heat into the boiler by 25%. Achieving this might be too much of a chore 4 the parents involved whilst improving the efficiency( Max 80% ) of the existing boiler is a lot more practical solution. Efficiencies in excess of 40% are rarely achievable for wood appliances and the For Sale columns in the papers are full of units 4 sale that have failed to perform to the standards people have been lead to believe they could.


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  • Registered Users Posts: 680 ✭✭✭copper12


    muffler hope this works
    keven how's it going
    Kevin007 wrote: »
    Secondly The moisture content of wood fuel is never below 10% and b4 you start to get any heat from your fuel this moisture has to be evaporated and the energy this takes ( Latent Heat of Evaporation ) should be deducted from the outputs that are quoted.
    It is not accurate’ to say that wood’ with a moisture content’ of 10% would reduce the efficiency of a boiler’ by the same amount
    Kevin007 wrote: »
    Thirdly If a solid fuel appliance is not cleaned thoroughly at least once a week, a 3mm deposit of soot on the walls of the boiler reduces the transfer of heat into the boiler by 25%. Achieving this might be too much of a chore 4 the parents involved
    This is not a very big undertaking and easily done and they would want to be very old and feeble not to manage something like this
    Kevin007 wrote: »
    whilst improving the efficiency( Max 80% ) of the existing boiler is a lot more practical solution.
    I would agree with you totally and should be of priority
    Kevin007 wrote: »
    Efficiencies in excess of 40% are rarely achievable for wood appliances and the For Sale columns in the papers are full of units 4 sale that have failed to perform to the standards people have been lead to believe they could
    This could be said about almost any product’ including’ gas; oil; and wood boilers.


  • Registered Users Posts: 45,680 ✭✭✭✭muffler


    You almost got it. At the end of the quoted text just add [/quote].

    Try it yourself by editing the post. :)


  • Registered Users Posts: 324 ✭✭Slates


    Kevin007 wrote: »
    Hi again
    Manufacturers and retailers of all boilers fail to tell the public that the efficiency of combustion boilers is measured by the uptake of heat returning to the boiler at 0deg.C and not the real temperature of 60deg.C This gives a completely incorrect and unachievable efficiency and is comparable to a car being rated on its fuel comsumption going DOWN a hiil and not up. Secondly The moisture content of wood fuel is never below 10% and b4 you start to get any heat from your fuel this moisture has to be evaporated and the energy this takes ( Latent Heat of Evaporation ) should be deducted from the outputs that are quoted. Thirdly If a solid fuel appliance is not cleaned thoroughly at least once a week, a 3mm deposit of soot on the walls of the boiler reduces the transfer of heat into the boiler by 25%. Achieving this might be too much of a chore 4 the parents involved whilst improving the efficiency( Max 80% ) of the existing boiler is a lot more practical solution. Efficiencies in excess of 40% are rarely achievable for wood appliances and the For Sale columns in the papers are full of units 4 sale that have failed to perform to the standards people have been lead to believe they could.
    Kevin, What do you think of this set up


  • Registered Users Posts: 18 Kevin007


    Hi Copper 12
    This looks like a drawing by System Link Ltd showing the installation of one of their 3 pump units for a SF and Oil/Gas installation I have seen this many times but refuse to use them because 1) They are very expensive 2) They use too many circulating pumps, Check and Isolating valves and too much equipment for what is after all only a house , not an office block and the more gear you have then the more likely it is to break down. I would only use one balance valve on each circiut or a motorised valve and thermostat if you want to control a bedrooms circuit. Bear in mind that you have here a Solid Fuel app over which you have very little thermostatic controll and you should try to design the circuitry so that in the event of a power failure the Heat will be dissappated thru a coil in the cylinder and also a radiator circuit
    Properly designed you should only need one pump on your circuits and not five as are shown on your drawing.
    PS Are you going to fit this for thefirst time as I reckon you are in the trade as know what you are at . Remember System Link et al would like you to buy their gear whether you need it or not. regards Kevin007


  • Registered Users Posts: 18 Kevin007


    Hi Slates
    Sorry I thought the drawing came in from copper12 and replied to him Apologies Kevin007


  • Registered Users Posts: 18 Kevin007


    Copper12 Sorry to contradict you but Solid Fuel and especially Wood burning units are never efficieent and those that burn moist wood are the worst of all the calorific Value of Fuel ( Wood ) allways assumes the moisture content to be Zero but for instance if you ask a Pellet Supplier what the moisture content is he may reluctantly tell you it is 10% but will not tell it could be 20% if you store it in a damp area over the Winter In a Winter season if one burns 10 Tons of wood at 10% You are only getting Heat from 9 Tons of wood and have to raise the temperature of ONE ton of water from 10deg.C to 100deg.C and then Evaporate it The energy this takes is VAST and is a net loss to the combustion load, and destroys the argument that wood especially damp is efficient.


  • Registered Users Posts: 680 ✭✭✭copper12


    Kevin007 wrote: »
    Copper12 Sorry to contradict you but Solid Fuel and especially Wood burning units are never efficieent
    The same could be said of any heating boiler
    Gas boiler operating at it’s maximum efficiency 90%
    If it burns 10 cubic meters; of gas’ you would only get heat from 9 cubic metres’ of gas. and that’s if your gas boiler; were 90% efficient’ which I doubt’ even if were a high efficiency boiler; and like you said running down hill
    Kevin007 wrote: »
    destroys the argument that wood especially damp is efficient.
    I don’t think anyone would argue with you that burning damp wood is inefficient; depending on the application
    How damp is damp 20% 30% 40%
    Wood for use in wood gasifying boilers recommended by manufacturers should not be above 25% this is an average taken from many different manufactures.
    Kevin007 wrote: »
    Wood burning units are never efficieent
    I would be of a different opinion; wood gasifying boiler; would be right up there; amongst the best of the oil and gas boilers
    One kilogram of wood at 15% humidity, provides 3.9 to 4.2 kWh. [/FONT]
    1 litre of fuel oil = 10 kWh[/FONT]
    The type- matter of the wood gas can look as follows:[/FONT]
    [FONT=Arial,Bold][/FONT][FONT=Arial,Bold][FONT=Arial,Bold]oxide of the carbon of CO 19%[/FONT]
    [FONT=Arial,Bold]hydrogen H2 18%[/FONT]
    [FONT=Arial,Bold]methane CH4 1.25%[/FONT]
    [FONT=Arial,Bold][/FONT]
    [/FONT]dioxide of the carbon 12%
    steam water H2O 2.50%
    nitrogen N2 the rest
    From these exchanged, only three first gases (coloured) are flammable.
    Most of the literature’ I have read on wood gasifying boilers from manufactures’ base there efficiency on wood; burning with a moisture content, of between 20% and 30%


  • Registered Users Posts: 680 ✭✭✭copper12


    I Meant to say how’s it going ;as well Keven007
    :rolleyes:


  • Registered Users Posts: 680 ✭✭✭copper12


    Kevin007 wrote: »
    I have seen this many times but refuse to use them because 1) They are very expensive

    Your right they a bloody expensive a rip off for a steel box; but they do the job. and made here in ireland


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  • Registered Users Posts: 18 Kevin007


    Hi Copper 12
    Some info 4u
    The calorific value of Dry wood is 19.2 GJ / Tonne
    The Calorific value of 45% Moisture Wood is 9.4 GJ/tonne
    In other words 2 tons of Damp equals 1 Ton of dry
    Tell all your Lumberjack Buddies to cut just 1 Ton but DRY it
    Happy Chopping
    PS. Check www.woodenergy.ie for further


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