DHW Heat Loss

[epsilonGreedy]

4 minutes ago, SteamyTea said:

Would it be enough in your loft?

 

 

Nope. I hope to get 350mm of fluffy stuff up on the loft. A 30 degree pitch creates a constraint for insulation above 300mm because near the eave it can bunch up and throttle air flow.

[ProDave]

3 hours ago, epsilonGreedy said:

 

I thought those blessed with Passiv house type thermal performance kept their ASHP ticking 24x7 and the UFH slab at a constant temp? What overnight temperature drop do you experience up to 6am in the winter? 

For reasons of silence, we turn the heating off completely at night.

 

This is probably best described as a "design error" but the original pipework restricted the flow too much and I had to add a second circulating pump to help to get the water flow high enough.  This works but there is a just audible low level hum from the second circulating pump that I would rather not have at night.

 

Lessons to avoid this situation:

 

For a HP install use larger (28mm) flow and return pipes.  Do not route said flow and return pipes under your bedroom floor, and it you have to fit a second pump, do not fit it in the plant room adjacent to your bedroom.

 

Even in the depths of winter the room temperatures drop a fraction of a degree overnight.  So there is no impact on comfort.

[Iceverge]

5 hours ago, ProDave said:

I can't understand why you would want to go to bed in need of a shower and not have it until the morning

 

There is a third possiblity, that one goes to bed clean and,  through some unspoken activities,  wakes up in need of a wash..........

[ProDave]

1 minute ago, Iceverge said:

 

There is a third possiblity, that one goes to bed clean and,  through some unspoken activities,  wakes up in need of a wash..........

As @SteamyTea says nothing wrong with showering twice.

[SteamyTea]

32 minutes ago, ProDave said:

As @SteamyTea says nothing wrong with showering twice.

Cleanliness is next to Godliness.

 

Edited November 11, 2021 by SteamyTea

[Nickfromwales]

10 hours ago, epsilonGreedy said:

A very interesting post, I might follow this advice.

You'll may also, then, benefit from some additional information re this DHW strategy. I have been routinely oversizing the DHW cylinder to create a larger 'cheap energy capacitor' which I have then designed around heating once a night at 5p/kwh and there then being enough DHW to get through a typical day without recharging. Options for interim recharge, where required out of off-peak times aka 'on demand' are; via immersion boost switch ( with a choice of 30 mins / 60 mins / 120 mins manual boost ) which I call "guest mode" or to set the immersion to boost midday where there is likely to be PV available, safe in the knowledge that the immersion will only call if the UVC is depleted and usually by not much ergo the UVC doesn't monopolise the PV production.

 

Freezing ( or the need to defrost ( two very different things )) is a statement I made as assumed. It can be mitigated or minimised ( risk / cause ) with a bit of thought.