Heat pump or distribution?

[midonald]

Hi folks. i wonder if anyone can help me with a central heating quandry?
I think I have decided to get involved with the recently announced renewable heat thingy. I thought it would simply be a matter of making a decision then going ahead with a heat pump and underfloor heating. However I have subsequently come across a heat distribution system it looks like I should consider but don't know why(I'm no heat engineer!!).
The systems main claims over UFH from what I can see are a constant flow and return drop of 5 degrees, a sensor/thermostat operating to 1 tenth of a degree, and a response time of 15/20mins. So I think it should cost less to run than UFH but how would it effect the efficiency of the heat pump? That is my main concern that I could lose at one end what I gain at the other.
Any input at all would help.
Hope I've got the right site.
Thanks

 

[simond]

A name of product, manufacturer or website would be a good start.

 

[Norcon]

However I have subsequently come across a heat distribution system

What type of "heat distribution system" have you came across?
Heat pumps work best with ufh where the lowest possible flow temperatures are involved.

 

[midonald]

Sorry. Didn't want to look like an advert! The System is Best board Radiant heating system. I have their brochure. UK website is www.heat-innovation.co.uk

 

[Norcon]

Radiant skirt heating via a heat pump?
I'd give that a wide berth.

Is that the guy who was on dragons den a while back where the dragons gave him a wide berth?
He could sell snow to the eskimo's though.

EDIT.
No it was a different guy I think.
http://www.youtube.com/watch?v=SD28oVG8aVs

 

[JohnD]

how are the skirting heaters powered? What is he selling?

does he provide any justification for his claims "for energy savings of up to 40% and with an average of 50% reduction on heating CO2 emissions"

Does "up to" include any figure, including 0%?

 

[midonald]

I think the claim is that they use less energy to create more heat!
Spoke on the phone to the chap last week. Long story short that by the fins inside releasing low temperature heat waves slowly up the wall the heat attaches itself to the wall which then reaches a certain temperatue the surface of the wall becomes a source of heat and results in a heating of the fabric of the building with a uniform temperature inside. Was told I could then heat my home at 17/18C and feel very comfortable? Does that make sense?

 

[electronicsuk]

Surely almost any form of radiator will heat the building fabric to some extent?

If you're considering the Heat Innovation products you link to, I suggest that you ask to visit an existing installation while this cold weather lasts. You can then verify the manufacturer's claims for yourself.

FWIW, it sounds a little suspect to me. What's more, skirting seems like a silly place to have your heating (especially if the majority of the heat output is radiant), as you tend to put things like sofas and cupboards in front of it!

 

[midonald]

I have done that. The experience was a little bit strange. It was a distinctly different warm feeling in the rooms relative to convection or ufh where the walls are cold. The chap was running at a 43% reduction in consumption over a two winters. I've done that bit I just wondered,as in my original post, that accepting that the distribution system is what it says on the tin would hooking it up to a heat pump make the pump more efficient or innefficient?

 

[Norcon]

The chap was running at a 43% reduction in consumption over a two winters

Who is this chap? The guy who is selling the product?

hooking it up to a heat pump make the pump more efficient or innefficient?

More inefficient.
The best efficiency is obtained when the temperature lift between the evaporating and condensing heat exchangers is kept to a minimum.
That means less pressure will be involved to force the refrigerant through the orifice in the expansion valve which in turn leads to less electricity being consumed.
With ufh and HP combined that means loop spacings of no more than 150mm and maximum flow temp of 35c and tiled surfaces where ever possible.

The HP sales guys like to get their systems into highly insulated new builds and then boast about how easy they are to run to other potential customers and fail to point out that its the insulation that is doing the work, not the overpriced machine!

 

[JohnD]

I think the claim is that they use less energy to create more heat!

can I interest you in buying shares in my Perpetual Motion Machine company?

 

[ajrobb]

The best efficiency is obtained when the temperature lift between the evaporating and condensing heat exchangers is kept to a minimum.

Yes, the best theoretical efficiency is calculated from the perfect Carnot cycle, which shows that in a heat pump it is important to keep the maximum cycle temperature as low as practicable.

After that, it is down to reducing pumping losses. Although a standard refrigerator cycle has losses caused by the isenthalpic expansion across the orifice, these can be less than pumping losses when trying to implement an imperfect Carnot cycle.