It is currently 29 Mar 2024, 14:13
9fingers wrote:.............Looking at this February. We had seven days where all our daily hot water needs came from the solar systems. Typically from mid March we will use no gas to heat water until mid October.
Bob
Rod wrote:Does that mean you are going to start knocking the house about?
Rod
Andyp wrote:Whats the problem with storing hot water?
I have One of these, sorry it is in french. But it is basically a large emmersion heater. It heats the water on an overnight tariff between 10pm and 6am to a temperature of about 50-60 degrees ( too hot for a bath without adding cold water). The outside of the cylinder never feels hot, in fact not even warm, so the insulation must be good. The water is as hot to the touch at 6am as it is at 9.30 pm.
I appreciate that pumping stored water around a CH system must reduce the temperature to a greater extent than just using it for hot water but hot water can be stored once heated, surely.
RogerS wrote:But surely if you have 'free' heat such as solar then it is worth storing it for later use ?
RogerM wrote:9fingers wrote:.............Looking at this February. We had seven days where all our daily hot water needs came from the solar systems. Typically from mid March we will use no gas to heat water until mid October.
Bob
Thanks to one of your previous threads, I fitted a solar immersion to our PV system last summer, and when we were away for 3 days at the end of Feb, with everything turned off, we came home to a tank of free hot water too hot to put your hands under. Even in the middle of winter, if there is some bright overcast, the solar immersion does the "heavy lifting" before the DHW system cuts in during the late afternoon. So a belated thanks for drawing our attention to it. Saved us a fortune.
Mike G wrote:Andyp wrote:Whats the problem with storing hot water?
I have One of these, sorry it is in french. But it is basically a large emmersion heater. It heats the water on an overnight tariff between 10pm and 6am to a temperature of about 50-60 degrees ( too hot for a bath without adding cold water). The outside of the cylinder never feels hot, in fact not even warm, so the insulation must be good. The water is as hot to the touch at 6am as it is at 9.30 pm.
I appreciate that pumping stored water around a CH system must reduce the temperature to a greater extent than just using it for hot water but hot water can be stored once heated, surely.
A thermal store is an altogether different beast from a normal hot water cylinder. The water in a thermal store is not the water which comes out of the tap, or circulates around a central heating system, both of which are heated via heat exchangers within the thermal store. In other words, instead of heating water up in a boiler and storing it for later use in a hot water cylinder, the boiler is constantly topping up the heat in a thermal store via a flow & return circuit and heat exchanger, and this thermal store then gives up its heat, via further heat exchangers, to the heating and hot water circuit. That store is kept at the same temperature all the time, 24 hours a day, every day. It's a wonderfully inefficient way of storing and using energy.
that prompted my post. As David pointed out9fingers wrote:I have come to realise that storing hot water is a mugs game unless the source of heat is free.
it is how it is used that causes the inefficiencies.chataigner wrote:.. the insulation is VERY effective. 300litres at 65°C loses heat at the rate of 0.1W. ie a loss of 2.4Wh per day or about enough to run a 40W lamp for 3.5mins.
RogerS wrote:Thanks for your comments, guys.
Bob..is your boiler a combi fed with mains pressure ?
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