General > General Technical Chat
Electric shower, anything I can do?
paulca:
--- Quote from: GlennSprigg on July 26, 2019, 12:54:15 pm ---I understand, but have always hated, the... "19th Century"... vs the... "18-Hundreds" nomenclature!
There's something unsettling in my 'brain' during quiz shows or what ever, getting it right !!
--- End quote ---
It's okay, the entire world (or the vast majority of it) celebrated the new millennia a whole year early.
There was no year 0. We started on year one, so the end of 2000 years happened on December 31st 2001, not 2000.
soldar:
I never understood the problem or the confusion. I guess it is because I was taught the difference between ordinal and cardinal numbers.
A baby in its second year of life is one year old.
In 1859 18 centuries had been completed but it was into the 19th century.
Different cultures count different ways. A baby is born into its first year of life so some cultures will say the baby is one, meaning it is in the first year of life.
Jesus Christ died on a Friday and rose on the following Sunday "on the third day". We would say only two days transpired but the way they counted Friday was the first day, Saturday was the second day and Sunday was the third day.
Seekonk:
I have PV water heating at my camp and those little 6 gallon tanks are plenty for a shower. 500W of grid tie panels (+60V) is sufficient to power the heaters in light use. I use a simple circuit that keeps the panels at power point and efficient. Even get to use the tanks existing thermostat at that voltage without arcing. A fun way to do a little solar that actually pays for itself.
paulca:
--- Quote from: soldar on July 26, 2019, 04:07:56 pm ---Jesus Christ died on a Friday and rose on the following Sunday "on the third day". We would say only two days transpired but the way they counted Friday was the first day, Saturday was the second day and Sunday was the third day.
--- End quote ---
I always had a pet hatred of inclusive/exclusive ranges. I still do. I 99.9% of the time get the right answer to questions like, "How many days are there until pay day?", pay day is the 25th, today is the 12th. 13 days. However I will 99.9% of the time refuse to accept the intuitive answer and disappear off the down the rabbit hole until I can mathematically prove to myself I've considered the inclusion or exclusion of the boundary numbers.... or counting the days on my fingers.
It's exactly the same as the suspicion new programmers have upon seeing:
for( int i=0; i<10; i++ ) {print i;}
It will execute 10 times, but 10 will never be printed. If you rewrite it as a while loop it's even worse.
i=0;
while( i<10 ) {
i++;
print i;
}
How many times and will 10 be printed? 10 and yes.
or
i=0;
do {
print i;
i++;
until( i > 10);
Sometimes I have to write a while loop in my head to work out how many days there are between two dates. :) (kidding)
Nauris:
--- Quote from: soldar on July 25, 2019, 07:20:13 pm ---The problem with using a heat exchanger in the big heating tank for domestic hot water is that (1) you need the big tank always hot, which makes no sense when you do not need heating, and (2) efficiency suffers.
--- End quote ---
Electric tank not much loss, it has great insulation all around but the oil boiler - that really sucks in the summer. Some people actually have electric tank for summer so the oil boiler can stay off, that saves a lot of oil.
--- Quote ---On demand combined heaters here do that and it works for certain values of "works". One advantage of not heating the domestic hot water directly with the flame but through an exchanger is that is adds a lot of temperature stability but, again, efficiency suffers a lot.
--- End quote ---
I drew a better schematic, this gives both temperature stability and good efficiency.
It is easy to integrate solar heating to it, also there is auxliary electric heater should the gas burner fail. Also solar power heats both water and radiators.
Gas burner is controlled by tank thermostat so that if tank falls below 50 C gas heats it up to 60 C or so. And if there is plenty of solar then tank temperature never fall and gas burner don't need to run.
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