Energy efficient heating/DHW

[brig001]

Hi, I have asked this on another forum, but didn't really get any help. Hoping someone here might have an answer (if there is one).

We are looking to replace our 13 year old boiler with something more efficient. Our current system has a Albion Mainsflow thermal store which is directly heated by a conventional boiler (Baxi Solo). Rads and UFH are fed directly from the bottom 1/3 of the store and there is an internal coil for the DHW. We pre-heat the DHW to the coil with a separate store fed from a solar panel.

1, Is it possible to connect all this lot to a combi?
2, Would a combi be more energy efficient than the store?
3, Is there a more energy efficient way of doing this?

Thanks,
Bri.

 

[Boilerman2]

Thermal Stores are well suited to Underfloor Heating, due to their abillity to supply low grade heat at a constant temperature, there are now thermal stores that can be heated by several different heat sources including Boilers, Wood burning stoves Air or Ground source Heat Pumps and Solar Thermal

Have a look at the following web site, this company ar a bespoke manufacturer and offer a design service , they are a really good source of information
www.chelmerheating.co.uk

 

[simond]

I think your question was, would a combi be more efficient.

Any modern boiler would create heat more efficiently than a Baxi Solo.

Would a combi boiler be more efficient than a heat-only boiler feeding a heatstore? The answer to this has been debated ad infinitum and the answer is, it depends on how you measure it.

However, if you use solar to preheat the DHW, this limits you to a few combis that have high temp rated incoming water equipment, and electronics expecting 50C water. Alpha have managed to get a blending valve through WRAS but I am told that gate is now shut to other manufacturers due to bacterial contamination concerns.

There are also flow rate issues with a combi so I would change the boiler No1 for a heat only, then maybe row out the Albion when it gets old for a better specced version.

If you decide to replace the heatstore an alternative is a DPS; their plate HEX versions will give a better HW flow rate.

 

[brig001]

Thanks both for your replies. I will just replace the boiler for a heat only. I have tried to find info on the relative efficiencies of instant hot water against stored hot water and found it's not cut and dried, so I guess there's not much in it either way. I think the heat only boiler would be cheaper and easier to fit and this would outweigh any efficiency difference anyway.

Thanks,
Bri.