alt.energy.homepower

"daestrom" wrote in message
news:46e30b6d$1$18959$4c368faf@ ...
>
> "News" wrote in message
> news:46ddcf3f$0$47143$892e7fe2@ ...
>> "daestrom" wrote in message
>> news:46ddbdcc$0$4071$4c368faf@ ...
>>>
>>>> Here in the US, most hot water tanks fail gradually, by leaking their
>>>> contents all over the floor. This generally happend withing a year or
>>>> two of the tanks warranty expiration. :-)
>>>
>>> Yep, been there. Can be extended if you take the time to check the zinc
>>> anode, but most folks don't even know where to look :-)
>>
>> In the UK unvented cylinders "tend" to be stainless steel. Look at this
>> all in one stainless steel boiler and tank-in-tank design - a tank inside
>> a thermal store:
>>
>> /
>> Manual:
>> /pdf/HeatMaster%
>> The manual explains the operation very well with nice diagrams too. It
>> always condenses promoting high efficiency.
>>
>> Here is a Dutch copper design - still very good.
>> / ?section=000200130001
>>
>> These units do CH and DHW and are "very" efficient.
>
> Yes, but I have to be a bit leery when the first one lists hot-water
> heating efficiency as '105%' :-)
>
> Apparently they are calculating based on the lower-heating value of the
> fuel. They can extract more than 100% of that heating value by the
> condensing of water out of the exhaust gasses. So I suppose for
> comparison with non-condensing units (which also use the LLV of the fuel),
> its best to stick with the same values. :-)

100% was based on "sensible" heat. When latent heat is taken into acount the
scale goes over 100%, up to around 109% maximum.

> Nice units, wish we had condensing
> hot-water heaters here in the states.

Energy is too cheap over there. Necessity is the mother of invention.

> I've got forced-hot-air heating for
> the home and separate hot-water
> heater. But it isn't anywhere near
> 90% of LLV, much less >100%. :-(

I believe the ACV units are available in the USA. These are the agents:
/CondensingBoilers/
A quick look and they sell the wall mounted Prestige at least. This also
comes as a stored water (integral DHW cylinder) on-demand water heater, that
also does CH. So it could heat a forced air unit with a copper coil. Most
forced air units are adaptable and can have copper coils fitted. Then one
condensing burner doing CH and DHW. The HeatMaster can also heat a copper
coil too. Just a thought.