New high-tech heating/hot water installation

[harvestmoon]

Hello,

I am about to embark on a total refurb project on a 3 bed end of terrace house in East London. It will also be extended to the side and rear to make a decent size 5 bed house.

Background:
I've just come back from Sweden where I saw an amazing heating/hot water system, but I don't know what to even search for here in the UK...

The central unit was the size of a large fridge and appeared to be a heat exchange unit. It had two separate heat sources - a Geothermal bore and an attached wood pellet burner. Apparently similar units can also support a third external heat source (eg: solar water).

The heat exchange unit had two outputs - a closed water loop for central heating, and a domestic hot water outlet (I think there is an integrated hot water storage tank).

I think the geothermal was the main heating source and also to pre-heat the hot water supply, while the wood pellet burner was used for peak heating load if required and to heat the hot water to the required temp.

Does anyone know about this type of thing (the heat exchange part rather than the heat source part)? Any suggestions on where to look for more info (manufacturers sites etc.)?

Proposal:
I am considering the above type of heat exchanger, but fired by a ground source heat pump, solar water & a gas fired boiler, but with the added twist of limitless hot water (rather than a finite supply in the storage tank). I don't know if this would be direct gas heating (like a combi boiler) or if the gas boiler just has to be powerfull enough to keep the heat exchange tank hot enough to heat the water as it passes through or even if it's possible at all.

Any alternative ideas, links or suggestions welcome!

Thanks.

 

[Agile]

You seem to be rather missing the gist of these energy efficient systems by thinking there is some kind of special "heat exchanger" involved.

The hub of these systems is a pretty low tech storage system with one, two or three heating coils.

The lower coil preheats the stored water with lower temperature from the geothermal heat pump ( if fitted ) or perhaps from the sustainable wood pellet burner. ( Where do you expect to get wood pellets in the East End? ) Plenty of old pallets if you want to spend 30 mins a day cutting them up and 45 min every evening driving round searching for them.

The top coil can be heated by a gas boiler to top up to usable water temperature but that involves another problem as the flow temp from the boiler is too high for it to condense efficiently.

All in all you need professional advice and many of the Sweedish methods are difficult to copy here.

Tony Glazier

 

[fitz1]

Agile, is the geothermal heat source the constant 50 degree land temp lifted with a heat pump.

 

[fitz1]

you could have geothermal underfloor heating and a wood burner tied in with solar panels for hot water.

 

[Agile]

Agile, is the geothermal heat source the constant 50 degree land temp lifted with a heat pump.

Not quite sure what you mean!

A few metres down the ground is at about 10 C and the heat pump increases this by about 30-40 degrees if you are lucky. Trouble is when you have been extracting the heat for a few days the ground can start to freeze!

There is another global warning problem which the enthusiasts seem to prefer to forget! Geothermal energy gives 3-4 kW for each 1 kW of electricity consumed. That 1 kW is only generated at about 33% efficiency so consumes about 3 kW of oil or gas.

The net advantage of carbon saving by using geothermal is very low and only in the region of 0-30%. In any event the cost of heating using geothermal gives little or no advantage over heating with natural gas ( if available ).

Tony Glazier

 

[fitz1]

sounds daft but southport built a eco friendly bus station.they bored holes approx 50 mtr down where there is apparently a constant 50 degree temp.they used two 7 kw heat pump at a cost of about 7 grand each to extract the heat for underfloor.if you have a source of flowing water like a stream you can use that .it aint going to freeze is it.

 

[Agile]

Fitz, are you still operating on Faraignheit ? ( I cannot even remember how to spell it! )

50 C is the daytime in the Saraha desert!

Tony

 

[fitz1]

50 degrees f .if its looped pipework , in winter it will draw heat from the ground and transfer it to the house. in summer it will take heat from the house and transfer it back into the ground.just found a site on it . will get back in a mo.

 

[fitz1]

http://geothermal.marin.org/pwrheat.html#Q2

 

[Biggles..]

worcester are currently designing ground source heating. the draw back with this is you either need a football pitch for your back yard and excavate about a metre or good access for a bore hole but to be affective has to be about 75metres deep so im led to believe. a lage country house near us in lincoln had it installed in the lake only 3metres deep but it extracted that much heat the lake frooze in summer. Im sure they'll get better designs soon.

 

[fitz1]

that would be an attraction. charge for outdoor ice skating in warm sunshine and that could pay the gas bill for your water.

 

[Biggles..]

Dont know if they have thought of that or maybe they could not pay the installer for bodging it as like you say in summer it should act in reverse and cool the house and heat the water.Either way more money coming in.

 

[fitz1]

doesnt sound like hes looped the system.