I can't imagine why one would want that. The DHE never captures 100% of the heat, and the shower mixer, thermostatic or not, does the rest of the control.
I looked at that too a while ago, not with any real intent. The showstopper there is that the recirc water must go down at least part of the drainage, where it can pick up all sorts of bugs.
It is actually. I expect their use will spread one day. No-one likes up front cost, but it pays its way and more.
NT
It hasn't. I measured the following temps one december:
35C water temp at the shower head 33C temp at top of plughole 19C ambient before shower, 22C after. Mains water incomer not measured.
Well, some of us have measured the numbers & done the maths. You haven't.
NT
So double it it up and have a 6kW shower?
3.5kW at 15p a unit for 10 minutes each per day x 4 people = 2.33kWh/day = 851kWh pa = £127 a year, or £3,810 per 30 year install life. 7kW wuold be 1700 kWh pa = £255 pa or £7,620 per 30 year install.
there is no flow control. And afaik showers normally remain the same temp t hroughout. At least I've never known anyone vary the temp much as they show er.
NT
Show us your numbers then.
NT
3.5kW at 15p a unit for 10 minutes each per day x 4 people = 2.33kWh/day = 851kWh pa = £127 a year, or £3,810 per 30 year install life. 7kW wuold be 1700 kWh pa = £255 pa or £7,620 per 30 year install.
there is no flow control. And afaik showers normally remain the same temp throughout. At least I've never known anyone vary the temp much as they shower.
Best stick an extractor fan in to f*ck up the calculations then.
All available on Ashley Madison
'Instant heat' showers bung a fixed power into the water and the knob controls the water flow and hence the temperature. By and large, the input water temperature at any one shower time is constantish, but varies substantially between, for example, summer and winter.
If you have a heat exchanger, then the input temperature will fluctuate as you decide to wash your hair, spray your balls or rinse the glass. Hence the flow control would need to be much better than just a simple valve.
Cheers
Most electric showers I have come across, bar some very upmarket ones, regulate the flow. Therefore the outlet temperature is dependant on inlet temperature for a given heat setting. That is why the dial might be set to "3" in the Summer and say "7" in the Winter.
So no measurements, no design, no calcs and hence no clue. No surprise.
NT
day = 851kWh pa = £127 a year, or £3,810 per 30 year install life.
mp throughout. At least I've never known anyone vary the temp much as they shower.
I cant imagine why.
Most showers are thermostatic. But I don't see much likelihood of noticeabl e variation in practice.
NT
with a DHE it'll be on a lower power setting. So what?
Makes sod all difference. Even if it did hypothetically, can you not set th e temp knob as desired?
NT
DHE?
Non electric ones certainly.
I've never seen a thermostatic instant heat shower, that's not to say there aren't any. In all the ones I've seen you simply control the flow rate manually.
Cheers
Drain Heat Exchanger apparantly.
Apart from the anti-scald device that cuts the juice when someone flushes the toilet or the washer starts the rince cycle, but not before it scalds you anywhay while it makes its mind up.
h/day = 851kWh pa = £127 a year, or £3,810 per 30 year install life .
temp throughout. At least I've never known anyone vary the temp much as the y shower.
eable variation in practice.
Unpowered mixer showers are or should be thermostatic. But its a nonissue r eally.
NT
So, you can't buy a domestic one because they're not commercially viable, you have to knit your own, make sure that it's efficient & cleanable, fit it somehow without rebuilding your bathroom, drains or house and then laugh all the way to the bank with the pennies you've saved whilst any family you might have had have moved out to somewhere with a decent shower?
Tim
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