thermo dynamics, whats more beterer?

[STIHLY DAN]

I have a helper coil in my furnace, that preheats an h2o storage tank for domestic hot h2o that feeds my water heater. Domestic Hot water runs from 5 am to 7 am non stop. then will sit idle till 7 pm for 1 shower and a load of dishes. I am using an 80 gal tank now, thinking of replacing with a 40 superstor. the 80 will give more preheated water with greater delta t to the coil. The 40 will feed hotter water but have less of a delta t. So is it better to preheat 80 or 40 in a 12 hr span? I could make an argument for both. What do you think?

 

[brenndatomu]

I'll give ya a bump cuz I'm a lil curious too. BTW, the grammar po-po says it's betterer.

 

[STIHLY DAN]

I'll give ya a bump cuz I'm a lil curious too. BTW, the grammar po-po says it's betterer.

Is it possible to misspell a non word?

 

[BrotherBart]

Everybody knows that it is "bestest".

 

[brenndatomu]

Is it possible to misspell a non word?

Online...yes

 

[STIHLY DAN]

Everybody knows that it is "bestest".

That is true, but what are your thoughts on the 80 compared to the 40 brother.

 

[BrotherBart]

Wrong person to ask. I have an electric water heater and love the thing. But for the life of me can't figure why you would want to heat 80 gallons that often.

 

[STIHLY DAN]

Ok, did a little homework. A 30,000 btu gas heater will heat 45 gal an hr at a 60* temp rise. A 4,500 watt electric heats 30 gal an hr @ 60* rise. 750 watts heats 5 gal an hr, Another 10* higher reduces 1 gal an hr. At 4,500 reduces 6 gal an hr. I figure with the coil at the bottom rear of the unit, relying on slow thermosyphom, that its getting 5-7 gal an hr. So a 12 hr burn with no one using hot h2o I should get 80 gal up to 112* with the 45 gal I would get 140* So that is 35 gal less heated water for 28* hotter. That's around 4 hrs of water heating getting wasted. So she is right! bigger is bestest.