[naffer]

In today's Sunday Times there is an item about a company called Zenex.
Zenex has built a pre-heater for the cold water feed into combi
boilers which is
designed to extract the last "bits" of energy from the exhaust and
dump it into the cold feed to the HW feed.

When I looked for Zenex on this site, so as to check, all I found was
a lot of stuff in 2006 which was a tad dismissive. Lots of science,
pseudo or near-science about it.

3 - 4 years on, what are the real experiences?
Alpha have rites to the technology and have built an integrated unit.

It seems that the technology is a tad obvious but the value depends on
the cost benefit ratio.

Ideas... Comments.

[YAPH]

On Sun, 07 Feb 2010 14:52:39 -0800, naffer wrote:

Alpha have rites to the technology and have built an integrated unit.

'Rites' - Freudian slip there!

I think Baxi have now picked up on it too.

Depends on the cost of the unit and the type of existing HW system, but I
suspect that in most real-world instances the return on investment will be
less than for measures like better draught-proofing, insulation,
architectural improvements (like building porches to buffer external
doors) etc.

--
John Stumbles -- http://yaph.co.uk

The ant has made himself illustrious through constant industry industrious
So what? Would you be calm and placid if you were full of formic acid?

[D.M.Chapman]

In article ,
naffer wrote:

3 - 4 years on, what are the real experiences?
Alpha have rites to the technology and have built an integrated unit.

It seems that the technology is a tad obvious but the value depends on
the cost benefit ratio.


I've got a alpha gassave fitted - I think this is the thing you've seen.

I was impressed at the amount of preheating it does to the incoming cold -
much more than I expected but obviously, it's only for hot water. It does
nothing to help with the heating circuits.

So, yes, it does work (better than I thought it would). Is it cost effective?
I doubt it if you had to pay normal rates - we got it as part of a pack with
a boiler and a store so it was a lot cheaper that way. We figured it was
worth a punt.

At the 800 quid list price forget it IMO

Darren

[Doctor Drivel[_2_]]

"D.M.Chapman" dmc@puffin. wrote in message
...
In article
,
naffer wrote:

3 - 4 years on, what are the real experiences?
Alpha have rites to the technology and have built an integrated unit.

It seems that the technology is a tad obvious but the value depends on
the cost benefit ratio.


I've got a alpha gassave fitted - I think this is the thing you've seen.

I was impressed at the amount of preheating it does to the incoming cold -
much more than I expected but obviously, it's only for hot water. It does
nothing to help with the heating circuits.

So, yes, it does work (better than I thought it would). Is it cost
effective?
I doubt it if you had to pay normal rates - we got it as part of a pack
with
a boiler and a store so it was a lot cheaper that way. We figured it was
worth a punt.

At the 800 quid list price forget it IMO

Darren

These are superb when used with heat bank/thermal store. The GasSaver has
its own pump, at the heat bank, and continually pumps heat into the thermal
store, so it works at all times. The pump is on when the boiler is running.
The pump can be eliminated by looping pipes around. The coolest part of the
heat bank goes into the Gassaver for preheat then into the boiler.

They will make back their cost quite quickly using them this way - depending
on heavy usage or not, it can be a quick payback. The bigger the house the
more it makes sense.

[Doctor Drivel[_2_]]

"D.M.Chapman" dmc@puffin. wrote in message
...
In article
,
naffer wrote:

3 - 4 years on, what are the real experiences?
Alpha have rites to the technology and have built an integrated unit.

It seems that the technology is a tad obvious but the value depends on
the cost benefit ratio.

I've got a alpha gassave fitted - I think this is the thing you've seen.

I was impressed at the amount of preheating it does to the incoming cold -
much more than I expected but obviously, it's only for hot water. It does
nothing to help with the heating circuits.

In modern highly insulated homes (especially the coming regs) the heating
costs will be far less than the DHW costs, so then they make sense. With a
largish family using much DHW, they make economic sense. One of the few eco
devices that do give a reasonable payback period.

So, yes, it does work (better than I thought it would). Is it cost
effective?
I doubt it if you had to pay normal rates - we got it as part of a pack
with
a boiler and a store so it was a lot cheaper that way. We figured it was
worth a punt.

A store. What kind of store?

At the 800 quid list price forget it IMO

Darren