The Christmas break has provided the opportunity to talk into the evenings with other family members, two of whom have engineering degrees.
The one most likely to buy a heat-pump in the near future asked "What arrangement should we have in order to supply five showers in a row at the start of the day?"
We tossed around the problem for a while, and considered the options:
size of Domestic Hot Water cylinder (too large and it can't complete an anti-legionella cycle with a 3kW immersion heater)
over-sized ASHP with large-bore pipes (but then needs a volumiser, and is less efficient in warmer weather)
install a storage battery to operate a (second?) immersion heater, and thus supplement output from the heat-pump (but how to prevent the HP shutting down?)
There was one option we couldn't resolve between us... ... in part because the device we'd require doesn't actually exist yet!
Could we use the tepid water in the volumiser, pass it through a water-to-water heat pump, and send the output to heat the top half of the DHW cylinder via a second coil?
I've placed Heat Pump 2 in the diagram as described in the text above.
Feel free to re-plumb the pipework, remove the volumiser completely or do whatever else you wish to make the physics work.
Doodle on my diagram if you want, and re-post it. I can tidy up whatever you suggest and create a posh version as required.
This topic was modified 2 weeks ago 2 times by Transparent
Persuading a couple of people to have showers in the evening instead of the morning would reduce the problem. A quick face wash in the morning is quicker and means more time in bed.
Persuading a couple of people to have showers in the evening instead of the morning would reduce the problem. A quick face wash in the morning is quicker and means more time in bed.
And, as an added bonus, the bed sheets won't need to be changed quite so frequently!
And I agree with you and @jamespa that an aerating shower head would contribute significantly towards a solution. Let me note here that such shower-heads require greater pressure in order to make the aeration process operate.
For example, I can't use one here because we have a well. That pump only provides 2.3bar at the shower mixer.
The photo shows an Ecocamel shower head. The company makes a number of water-saving devices, including those which work in hard-water areas.
It's not an issue that would've occurred to me when I was in Rwanda or Pakistan, for example!
But it's here in UK that HMG is promoting a not very successful migration from boilers to heat-pumps. And poor user-experience is dissuading households from adopting them.
Whilst the total fertility rate (TFR) in UK is 1.7 and falling, there are a significant number of larger households. Many of these are found within particular religious groups, for whom daily 'bathing' is the cultural norm.
Within this Forum we should be able to find solutions to these issues.
As an aside, I provided my teenage daughter with a sand-timer to stick on the wall and remind her that lengthy showers were to be discouraged.
A couple of weeks later she complained that it was just too much effort to have to keep turning it over!
This post was modified 2 weeks ago 4 times by Transparent
It's not an issue that would've occurred to me when I was in Rwanda or Pakistan, for example!
But it's here in UK that HMG is promoting a not very successful migration from boilers to heat-pumps. And poor user-experience is dissuading households from adopting them.
Whilst the total fertility rate (TFR) in UK is 1.7 and falling, there are a significant number of larger households. Many of these are found within particular religious groups, for whom daily 'bathing' is the cultural norm.
Within this Forum we should be able to find solutions to these issues.
As an aside, I provided my teenage daughter with a sand-timer to stick on the wall and remind her that lengthy showers were to be discouraged.
A couple of weeks later she complained that it was just too much effort to have to keep turning it over!
Fair enough. Perhaps your daughter could be asked to contribute to the cost or reminded that she will (likely) outlive you and will thus suffer the effect of Climate change rather more than you will!
Re
"Within this Forum we should be able to find solutions to these issues." Within the forum we cant change the specific heat capacity of water, the incoming water temperature or the size of houses and hence heat pumps.
The fact is that there are in practice a range of solutions (many of which are outlined above by me and others) but none are as simple as a combi boiler (other than the obvious namely heat the tank to a higher temp). Prior to combis we were all used to having limited hot water, unfortunately they changed that and so now expectations are high.
I think this is an area where installers may need to be a bit clever and work with the householder in a positive way. Many bill payers may appreciate being forced to limit the length of showers (a not impoverished relative of mine, for example, has installed a smart shower which has an adjustable time limits that he can set on his smart phone, exactly for this purpose). Others (perhaps the majority) wont care that, if they heat the water to 60C using the ASHP, they will be doing so at a COP of only 2 - with the right tarriff it can still be cheaper than gas! Others will be quite happy with a split showering regime...
I honestly cant see a situation occurring very often where there is no solution, unless the homeowner displays no flexibility at all.
Efficiency and cost of energy do not necessarily align - so we have the rather dumb result that it is cheaper to use more energy at a lower COP but still be ‘cheaper’ to the consumer than if might be at other times! The overall environmental costs may be at variance with this.😒 Regards, Toodles.
Toodles, he heats his home with cold draughts and cooks his food with magnets.
Perhaps your daughter could be asked to contribute to the cost or reminded that she will (likely) outlive you and will thus suffer the effect of Climate change rather more than you will!
Alas... too late.
For even now, said teenager is in Australia. Never underestimate how far some people will go for a decent shower.
The moral of this sorry tale is thus:
If you too wish to keep your daughter Then do not skimp on showering water; Your heat-loss survey tells you whether Your family remains together. The heating engineer you'll thank That he installed the right-sized tank.
