Sending power to Summerhouse

[JohnW2]

ISTR that the rate of heat loss, or transfer from A to B, is proportional to the gradient between A&B.

Indeed so.

If so surely a cylinder of hot water will lose more heat if kept at a high temperature than if it is allowed to cool?

Again, indeed, that would seem to 'obviously' be the case. However, as above, if a particular human being has less 'hysteresis' than a thermostat, it is theoretically possible that they could keep the water at a higher average temp than would the thermostat.

However, it may be more complicated than that. In the case of the immersion, the water at the top of a standard DHW cylinder tends to stay relatively close to 'working temp' even when some of the hot water is used and replaced with cold water at the bottom of the tank. I need to think about whether that has any bearing on what we are talking about.

Kind Regards, John

 

[ban-all-sheds]

But then there’s also this type

What's the (likely) starting current of a 4HP water pump?

So they're a warm bacterial stew of exfoliated skin, hair, grease, grime and bodily fluids.

Given how friendly 6 people in the one pictured would have to be, the latter does not surprise me.

 

[ban-all-sheds]

Well, I worked out an example to see what ballpark it's in...

800 litres, from 15° to 37° (just picked because it's body temp), with a 2kw heater, would take 10.2 hours!!

With real world losses, it's not going to be quite what people had hoped for!

And to those losses, other factors can be added.

I've never had the pleasure of wallowing in a pool of other people's exfoliated skin, hair, grease, grime and bodily fluids, but isn't hotter-than-body-temperature preferred?

Good luck finding water at 15°C to fill it with, too...

 

[JohnW2]

I've never had the pleasure of wallowing in a pool of other people's exfoliated skin, hair, grease, grime and bodily fluids ...

Never been in a swimming pool?

Kind Regards, John

 

[ban-all-sheds]

Ah.

 

[ban-all-sheds]

I was going to say that I have never "been" in a swimming pool , but as a young child, who knows.

 

[rsgaz]

but isn't hotter-than-body-temperature preferred?

But your skin isn't at 37°, that's your core temperature, so 37 degree water feels nice and warm.
(edit: urine would be at 37°, so it's that warm!)

Good luck finding water at 15°C to fill it with, too...

Don't follow what you're getting at there, just measured my tap water at 16.2°, but initially I had in mind a tub that was already full, more of a kind of 'average outdoor temp' really.

 

[stillp]

Never been in a swimming pool?

Kind Regards, John

More volume of water, with added chlorine and constant filtration.

 

[JohnW2]

More volume of water, with added chlorine and constant filtration.

Certainly a greater total volume of water, although I'm not sure that the volume/person would necessarily be higher (or, at least, a lot higher) in a crowded swimming pool than a hot tub!

As for the other measures you mention, I thought (but may be wrong) that decent hot tubs had similar. Many of the potential contaminants probably 'sound unpleasant' rather than being dangerous, but I would have thought that some measures would be required at least to deal with the likes of Legionella.

Kind Regards, John

 

[davelx]

I thought (but may be wrong) that decent hot tubs had similar.

Kind Regards, John

You are not wrong. They also have the similar water testing kits to those used in swimming pools, and the same or very similar chemicals to add chlorine and adjust the pH.

 

[stillp]

Certainly a greater total volume of water, although I'm not sure that the volume/person would necessarily be higher (or, at least, a lot higher) in a crowded swimming pool than a hot tub!

As for the other measures you mention, I thought (but may be wrong) that decent hot tubs had similar. Many of the potential contaminants probably 'sound unpleasant' rather than being dangerous, but I would have thought that some measures would be required at least to deal with the likes of Legionella.

Kind Regards, John

I've only looked at two hot tubs, and neither had any facility for automatic chlorination. One had a filter, about as fine as a tea-strainer, i.e. useless.

 

[Iggifer]

What's the (likely) starting current of a 4HP water pump?

Even at 5x inrush - 65A!. I can only assume there's some clever soft start doohickeys in there to prevent that problem. But even once it's running the pump is pushing 13A on it's own. There must also be an interlock so you can have heat or circulation, but you can't have both!

 

[Iggifer]

quoted instead of editing. doh

 

[JohnW2]

quoted instead of editing. doh

I'm pleased to hear that I'm not the only one

Kind Regards, John

 

[ban-all-sheds]

I'm pleased to hear that I'm not the only one

Kind Regards, John

Mmm. Common the problem is.