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| Electric shower, anything I can do? |
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| soldar:
For space heating I prefer, if possible, the greatest heating exchange surface and the lowest fluid temperature. That is the most efficient because the takes most heat out of the burning gases. If I could I would install subflooring heating but it is too expensive to retrofit. So the thing is that if you want domestic hot water at 55ºC then you need the water tank to be at substantially higher temperature which means lower efficiency because you could be heating the house with water at 45ºC and gaining in efficiency. All engineering solutions are compromises. Regarding the heat losses of a tank I guess they can be minimized as much as you want by adding insulation. I should measure how much my tank loses. In the winter it does not matter but in the summer it would add a bit of load to the AC. |
| paulca:
--- Quote from: soldar on July 26, 2019, 08:49:31 pm ---Regarding the heat losses of a tank I guess they can be minimized as much as you want by adding insulation. I should measure how much my tank loses. In the winter it does not matter but in the summer it would add a bit of load to the AC. --- End quote --- I can't remember exact figures, but someone on here mentioned how much temperature their tank lost overnight in 8 hours and we worked it out as something like 90W of heat loss. Not much, modern insulated tanks are surprisingly efficient at holding heat. My own, old copper tank, with a tied on blanket to insulate it is still perfectly warm at bedtime when the heating was only on for 30 minutes at dawn. |
| soldar:
Heat loss will depend on the size of the tank and, importantly, on the temperature of the water. 90W sounds like a reasonable figure from an engineering point of view but I would try to bring it down with additional insulation. 90W over a year can add up to more than 100 euro. To put it in perspective, my refrigerator uses less than half that. It has a 100W motor which is running on average less than 45% of the time. That is an advantage of on-demand heaters. No heat loss when not in use. I have a tank in my second home and when I am away I turn it off which means waiting some hours for hot water when I return. Not a problem for me at all but it might be for some people. Also, I may arrive for a weekend, heat the tank and leave so most of the heat will be lost and wasted. |
| GlennSprigg:
--- Quote from: paulca on July 26, 2019, 04:54:40 pm --- --- 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) --- End quote --- Yep, the examples you quoted can be (are) tricky to the uninitiated, though each coding has it's purpose/use. I was going to respond here, 'next Tuesday', (Sunday here now), but I think I've been told that this will mean that I wouldn't reply for 9 days, instead of 2 days time !! 8) My apologies to the O.P. for going off topic again... ;D |
| james_s:
--- Quote from: Someone on July 26, 2019, 03:22:46 am ---Its like you are living in the 19th century. We have controls inside the house to set the temperature, no messing with mixer taps to try and get the temperature where you want it. --- End quote --- I've never seen anything like that before in my life, a standard mixer valve in the shower is virtually universal in the US, little has changed in the last 60+ years other than pressure compensating valves that will maintain a constant ratio regardless of pressure changes on hot or cold. |
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