Jump to content

A more simple approach to dhw


Recommended Posts

As fitted in an an apartment in Poland.  Perfect surely for a 1-2 person flat.IMG_20240119_083308195.thumb.jpg.e08c1a5b61f60d2eee3bfd0946eb1dec.jpgIMG_20240119_083259646.thumb.jpg.b571dd3b14f8b870c4a89e3628db14cb.jpg 

 

I'm posting this in view of the many discussions about the challenges of dhw with ashp.

 

Sometimes I think we make things too complex!

 

Link to comment
Share on other sites

4 minutes ago, JohnMo said:

Maybe, but it's actually a small UVC, but normally below a nominal size, that doesn't require G3 regs

The model pictured is actually 50l which I believe would require G3 in the UK. There is what looks like a prv on the cw inlet (just about visible in the photo), which vents to the tiled floor of the bathroom.  Ariston do bigger ones as well, the one in the picture is the size of a combi.

 

I guess my point is that others seem to be able to find solutions to things we make extraordinarily difficult. 

Link to comment
Share on other sites

4 minutes ago, JamesPa said:

I guess my point is that others seem to be able to find solutions to things we make extraordinarily difficult. 

I have often said that for every law that says we must do some, we have another law that makes it illegal.

 

Link to comment
Share on other sites

2 hours ago, JamesPa said:

I'm posting this in view of the many discussions about the challenges of dhw with ashp.

ASHP, heat pump unvented hot water tank, heated to 48 degrees.  What challenges are you thinking of?

  • Like 1
Link to comment
Share on other sites

8 hours ago, ProDave said:

ASHP, heat pump unvented hot water tank, heated to 48 degrees.  What challenges are you thinking of?

In a retrofit for a small house or flat: locating the tank, running the primary feeds to the tank and most problematic of all, the (totally ott) g3 vent which is a real problem even in my much larger retrofit, even more so if you follow the building regs as regards notching and drilling (which I guess many dont).

 

Easy in a 200 sq m newbuild, a real pita in a retrofit which is >90 percent of the market that we need to tackle.  More to the point the dhw is a significant part of the ashp retrofit cost and disruption because of how difficult the industry has choosen to make it.

Edited by JamesPa
Link to comment
Share on other sites

9 hours ago, Simon Cook said:

Yeah this is very common in parts of Europe but only for showering.

what do you have for heating the apartment?

Radiators, not sure the source of the hot water for the rads.

 

It's not mine, I'm just staying there.  I posted it to point out that there other ways to deal with one of the current disincentives to ashp retrofits, if only we would get out of our box and learn from others.

Edited by JamesPa
  • Like 1
Link to comment
Share on other sites

DHW is typically less than 25% of a home's energy consumption, sometimes alot less in older houses. 

 

It would seem that, if the proportion of extra cost to provide DHW via the HP is greater than that % there should be the option to ditch it - especially if the DHW is already being provided electrically eg direct vented cylinder. 

 

 

Link to comment
Share on other sites

15 minutes ago, Beelbeebub said:

DHW is typically less than 25% of a home's energy consumption

Wish it was for me.  It is, as you acknowledge, small because of our leaky houses.

 

Environmentally heating water with a resistance heater is not going to be a problem, the problem is generating enough low carbon electricity.

If we say a house uses, on average 4 kWh/day for DHW, that is 120 GWh a day for the nation.

A basic HP with a CoP of 2 will halve that.

  • Like 1
Link to comment
Share on other sites

11 hours ago, Beelbeebub said:

DHW is typically less than 25% of a home's energy consumption, sometimes alot less in older houses. 

 

It would seem that, if the proportion of extra cost to provide DHW via the HP is greater than that % there should be the option to ditch it - especially if the DHW is already being provided electrically eg direct vented cylinder. 

 

 

I agree where the proportions are as you say and there is no reasonably viable alternative.   That and be more flexible over alternative options for achieving the g3 requirements rather than slavishly insisting that the non-mandatory guidance is followed.  The industry needs to start serving its customers, currently it seems to be the other way round.

Edited by JamesPa
Link to comment
Share on other sites

29 minutes ago, JamesPa said:

be more flexible over alternative options for achieving the g3 requirements

If you can't or won't fit an UVC - there is it's an open vented cylinder as pointed out by @SteamyTea this could be direct or indirect or a thermal store like a Harlequin, or point of use direct heaters. Plenty of options for DHW heating.

 

Nothing mandatory about installing an UVC. There will be plenty of properties where installing a unvented cylinder is wholly inappropriate, due to water pressure and flow issues.

Link to comment
Share on other sites

7 minutes ago, JoeBano said:

You can always fit the UVC in the loft. Seen it done plenty of times 

Not in a flat you can't! 😁

 

The big issue is the space needed to store the heated water, especially as it will be stored at near use temperature rather than high temps and blended down to a lorger volume of use temp water. 

 

An unvented cylinder could be made cubic to help give extra 25% volume and if a pressure booster pump was included that might do. 

Link to comment
Share on other sites

15 minutes ago, Beelbeebub said:

The big issue is the space needed to store the heated water

It can be distributed though.  More plumbing, though if you have two bathrooms, a downstairs bog and a kitchen, not much more.  You are, after all, just running a cold feed to each heater.

 

There is a case for properly sized instantaneous heater, though they may need a huge power delivery and cannot make use of ToU tariffs.

 

Then there is the 'ecocent' type HPs with storage.  Especially useful if you need to ventilate your old, damp, thermally leaky house.

Link to comment
Share on other sites

1 hour ago, JohnMo said:

If you can't or won't fit an UVC - there is it's an open vented cylinder as pointed out by @SteamyTea this could be direct or indirect or a thermal store like a Harlequin, or point of use direct heaters. Plenty of options for DHW heating.

 

Nothing mandatory about installing an UVC. There will be plenty of properties where installing a unvented cylinder is wholly inappropriate, due to water pressure and flow issues.

All fair enough, but we could still do with some more flexibility for uvc placement etc that provide options to the rigid way G3 is interpreted.

 

As it happens I think I have finally found a viable route for the vent for mine (other than putting it the loft, which is wasted energy).  This is perhaps the only upside of the  delay caused my lpa!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...