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# Watts required to heat water

(Dave Howorth) #21

IassUme - he needs to tell us

(Bill Thomson) #22

You’re preaching to the choir here, Dave.

Lack of info from the users when asking for help with an issue has been a recurring theme here as long as I
can remember. (and I’ve been an active member / moderator here since 2013)

If you’ve got any ideas / suggestion on how that could be improved upon…

(mike) #23

Sorry guys on vacation. Trying to use my phone instead of computer. My state is Arkansas. Same lat as Alabama. Just farther West. Not so cold here. Sorry for the delay and my poor typing skills using phone.

(Bill Thomson) #24

Hi Mike,

Got AL from an IP lookup, so there was bound to be a degree of uncertainty. I stand corrected.
(I’m in OK)

Regards,

Bill

(mike) #25

back from vacation, oh yeah, the wonderful keyboard.

Ultimately, whilst it will be an interesting project and it will certainly help cut your heating bills, it will probably need to be backed up by the heat pump kicking in at some point into the evening

Calculating the heat input to obtain the requisite temperature rise is easy - knowing or estimating the losses in the process is the hard part.

i believe these 2 statements to be correct. my opinion now is that it could help some but i’m still going to need my heat pump. knowing exactly how much its going to help would require special equipment. thanks to everyone for your help but this question has been answered the best it can. im moving on to the best way to heat the water, but that will be a new thread.

(Robert Wall) #26

But it’s not impossible. First, you need to know the cooling losses. The way I’d go about that is heat the tank up, then allow it to cool as it would, without drawing off any hot water and replacing it with cold, and record the temperature as it cools. Knowing the rate of change of temperature and the volume, you have the rate at which it loses energy to ambient, which is the same as the power to maintain it at that temperature. The next part is to measure or estimate the amount of heat taken out by using the hot water, which again requires a knowledge of the temperature difference (between the hot water and its cold replacement) and the volume.