| General > General Technical Chat |
| Electric shower, anything I can do? |
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| paulca:
--- Quote from: SteveyG on July 26, 2019, 09:50:16 am ---Personally, I would not choose a system boiler. If you're going down the route of an unvented cylinder then go for a heat-only boiler and keep the rest external - it'll be more maintainable. Have you measured your water supply to even know if a combi boiler is a viable option? --- End quote --- I have a heating company coming to do a survey on Monday, so I'm sure they will test this and present me my options. What do you mean "heat-only" boiler? Do you mean that the boiler heats only the radiators and not the water tank or do you mean a combi boiler with on demand heating? If it's "heat-only" I would of course need another way to heat hot water. Electric heater is not really an option due to cost and environmental aspects in that electric heating is the least efficient by a fact of around 3. Basically the utility company burns oil or gas to produce electricity at about 35% efficiency, making electric heating only possibly viable for heating a single room, where running the whole house heating would be wasteful. |
| soldar:
--- Quote from: paulca on July 26, 2019, 10:29:36 am ---Solar PV -> MPPT Controller -> DC Immersion heater is more efficient here as at noon 1kW of panels will still produce close to 1kW of power, even in the dead of winter when it's -10*C outside. --- End quote --- Interesting. Never seen that. |
| Someone:
--- Quote from: soldar on July 26, 2019, 08:18:53 am ---First you said: --- Quote from: Someone on July 25, 2019, 11:25:15 am ---All the units I'm familiar with do have power control with ratios over 20, even beyond a factor of 30 so based on your choice of numbers they work fine. This is going back 20 years so its nothing new or exclusive, there are multiple suppliers of products which meet those requirements. --- End quote --- Now you contradict that: --- Quote from: Someone on July 26, 2019, 03:22:46 am ---500W is down in the electric power level, most gas systems bottom out at a few kW but since they are all continuous flow models you can have multiple in series/parallel configurations for people with very special requirements for ranges or volumes of water. --- End quote --- --- End quote --- No contradiction, there are instantaneous gas heaters with 20x or greater dynamic range, and there are small electric instantaneous heaters suited for low flow/low power requirements. Instantaneous gas heaters are not suited to low flow situations as you have pointed out as they have limited dynamic range, but those limitations are overblown as few people have need for low flow at a low temperature rise. |
| richard.cs:
--- Quote from: soldar on July 26, 2019, 11:17:36 am --- --- Quote from: paulca on July 26, 2019, 10:29:36 am ---Solar PV -> MPPT Controller -> DC Immersion heater is more efficient here as at noon 1kW of panels will still produce close to 1kW of power, even in the dead of winter when it's -10*C outside. --- End quote --- Interesting. Never seen that. --- End quote --- That approach has been discussed on here a few times. Overall efficiency is much lower in terms of Watts per roof area, but unless you are space constrained you use a larger area of PV to get the amount of heat you want, and the total cost of ownership can be lower that an equivalent solar-thermal system because you don't have wet circulating loops, pumps, etc. to maintain and because PV benefits a lot from economies of scale. |
| GlennSprigg:
--- Quote from: Someone on July 26, 2019, 03:22:46 am ---Its like you are living in the 19th century......... --- End quote --- I know I'm digressing, but that's what makes life interesting... :D 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 !! An old German friends mother was talking to me once. I may be shot down here, but I was told she uses 'old' German, to describe the time ??? To me, if it was say "9:40pm", we would say it like that... However, she would say... "It is 5 mins until 3/4 of 10"... Aarrgghh xxx :-\ |
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