to that, Oil is only £1 more per year then mains gas - this was in
2003
With the recent price hike in gas, would oil be a better choice over all?
Are the installation and maintenance of oil boilers more then gas? How about the cost of installing a tank and any maintenance required? Costs of delivery for the oil?
LPG is more expensive than oil, but all maybe not lost. Zenex, has introduced a "top box" that fits on a condensing boiler's flue. Out of the boiler into the box and out again to outside. The return pipe pass through the top-box and out to the boilers return. This appears a big "leap" in making condensers more efficient.
They announced it pre-Xmas, but now it is on sale.
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here:
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extracts even more latent heat from the flue of a condensing boiler. They claim, with some independent validation, that a "condensing" boiler can save 30% of its heating bills. There are no moving parts.
They claim that a combi can deliver 50% more water flow for the same input - so a 12 litres per min job will be 18 litres, a big hype that fills a bath pretty fast instead of a leisurely fill.
They are developing a 15kW combi that delivers 12 litres/min - a little better than the average combi around. 12 litres is normally only achieved by a 28kW boiler. So, at 15Kw it is not oversized for the CH in flats, and the case size can be kept down.
They plan a box for a non-condensing boilers too, that will bring non-condenser into condensing territory.
They claim the price will fall from £595 as production gears up. If it get to half, and it does what they say, then this can save a lot of fuel, the bigger the house the more fuel saved.
The versions may be suitable for LPG boilers - check it out. This top-box may well make an LPG boiler equal, or better, than an oil boiler to run and with £600 on top probably still lower capital costs of installation than oil too. Worth assessing.
....and large too. Although they do have outside models, and the combi versions tend to have a small thermal store inside (sometime quite larges stores too) as the burners are slow in responding. Hence the flowrate of oil combi boilers can be quite pleasing. So, one of these installed outside can eliminate tanks and cylinders, and have "no" major heating and water appliances in the house.
We have an induction hob too - and as Christian also said, haven't looked back! So much easier to keep clean (main point) Just as controllable (Probably more so - there are 18 steps on the digital controller. It has timers, so you can set something cooking, and tell it to turn it's self off. If you remove a pan it goes off immediately (Well, as the pan is the element, it would!) If you leave the pan off for long enough, it turns its self off completely.
We do have a single large gas ring for the wok though!.
As a condensing boiler is supposed to be 90+% efficient how can they extract another 30% from the waste? Maybe they are lying, maybe the boiler manufacturers are lying, but they can't both be true.
There is: Sensible heat (from the flames) Latent heat(from the flues gasses).
30% extra from the latent heat? The article does say 30% more efficient. The editor of HVR magazien says in his leader:
"the product independently tested by GasTec and it offers DHW improvements of more than 30% when compared with ordinary SEEDBUK A-rated boilers. Forget all this energy rating stuff, anyone who offers me a saving of 30% of my heating bill is OK in my book, especially as British Gas has just put up its prices again." "I believe that this is, for now, the closest to a quantum leap".
BTW, the condensing range currently goes up to 109%. The 100% range only takes in account senible heat.
Viessmann collaborated with them on a job in Plymouth. A company like them does not chase lost causes or pseudo engineering.
No but they claim to be able to alter the rules of physics. Maybe they will be doing cold fusion or zero point energy soon?
If you do actually condense the water out of the flu in the boiler then there just isn't 30% of the energy left in the flu gas, it isn't hot enough. So either condensing boilers don't work or the secondary heat exchanger doesn't get anywhere near 30%, its simple really.
Its probably a made up figure..
say..
in the middle of winter you have the heating on 24hrs a day then you get enough heat out of the system to save you 30% of the little bit used for the DHW and not 30% of the total.
You probably save a lot more if you have a heat exchanger on you air ventilation.
But they are talking about cooling the flue gases down to 50C. So what temperature are they expecting the return to be? If the return temp is anything like this it won't cool the flue gases at all.
On 60-40C temp differential across the rads you would. Also having a load compensation control system that drops the return temp, or weather compensation, or both will certainly improve matters, as the return will be below 50C a lot of the time.
"but it has the most energy efficient technology as independently tested by GasTec Certification Bv Holland to European test requirements of PrEN13203 achieving a 38% winter mode improvement in domestic hot water and an unspecified but significant gas saving calculated by Zenex to be in excess of 30%, a combined benefit of more than 60% reductionin DHW generating costs and it can be applied to today's products".
GasTec say 38% improvement in DHW alone. If the cold mains is run through one, the flue gas temperature will drop substantially that is clear. Then the main boiler takes over from there. The main heat exchanger in a condensing boiler has to operate with a specified Delta T.
What this is doing is staging it. An analogy is: You have a thermal store where the bottom may be 25C and when heated it must be heated all in one pass of the stored water through the boiler. A boiler raises primary water temperature by say 35C. If the return water of say a thermal store is say,
25C the boiler only has a flow of 60C, so the stored water has to circulate at least twice through the boiler. You may want the store up to 80C, so you are 30C short on the flow, Piping the flow on the boiler into the return of another boiler (two in series) the water can be raised "in one pass through the boilers to 80C". He is doing something similar to this, but with flue gasses. His box can improve combi flowrate perform brilliantly. There should be no need for 9 litres/min cloggers anymore.
You can make your own. As an e.g., look at the gfx shower drain heat recovery unit. A boiler that uses plastic flue pipe can have one of these in the flueway and the mains water piped down the spiral around flue pipe. This would extract latent heat from the flue gas even further, "and it is totally legal", as you are not interfering with the passing of the flue gasses; no baffles or whatever. I don't think copper pipe would like long exposure to flue gasses and acidic condensate though. So, a pipe within pipe using two plastic pipes with the inner being the size specified for the flue should work. If you ran 30 metres of plastic exhaust pipe (normal drain pipe) outside, which you can, in freezing conditions the flue gas will condensate even further and the condensate falls back to the boiler. Instead of releasing the heat to the surrounding air, you are merely harnessing it.
Going back to the OP's question, if you want to install a non condensing oil boiler you need to do it before April 2007.
I have just tried ringing the local building control people to enquire whether I could install a non condensing oil boiler post April 07 because of difficulty installing a condensate soakaway (I am not on mains drains). The told me to speak to HETAS (Who I now realise deal with solid fuel boilers!)
The ODPM told me that it is the local authority who have the discretion to disregard the regulations. (not the installer) The problem is that they don't appear to know how to do this.
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