OT: Europe

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#22

Jim,

Have you considered a solar powered mini-split air conditioning system? I self-installed one in my garage as an experiment and it has worked well. I have 6-385 watt panels mounted on a platform I built in the back yard behind the garage. The unit only requires 3 panels to run but I wanted excess capacity in case of partial sun. It’s also hooked up to 230v from my garage AC panel, and it switches automatically to AC power when it’s totally cloudy or at night.

We live in hot and hurricane prone Texas and the garage is my back up “cool room” in case we lose power. It’s also a heater for the winter when we lose power from our old, creaky, mismanaged grid. I just leave the unit running all day in the garage so I can easily cool off after working in the yard or doing other projects. I’m trying to talk my wife into letting me install one downstairs in our house for additional, more efficient cooling over our traditional (almost 100,000 total BTU!) air conditioning we use.

I have the ACDC12 unit and it cools the garage sufficiently, even though it’s not well insulated. They also sell a bigger 18000 btu unit. These systems don’t require any batteries, which makes the install easier and cheaper. I have no affiliation with the company, but just think running air conditioning and heat off solar is pretty neat!

https://www.hotspotenergy.com/solar-air-conditioner/

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#23

Have you considered a solar powered mini-split air conditioning system?

This remains way off topic for the board, a digression from a digression.
But for those geeks interested—

I’m looking at a PV system as well, entirely separately.
I have a flat roof that will hold 24 panels at 10 degree slope (zig-zag mount) if the city will let me (heritage protected area).
It will produce a lot of power at peak, maybe 9kW?, but still not enough for the HVAC at full tilt.
This is a rambling old house, zero insulation except the attic, very hot climate.

For this property, my existing air con situation:
I have a split air con system now, chilled water circuit, as well as a completely separate gas boiler for radiators and domestic hot water.
I want to replace the gas boiler with a high-temp heat pump system to stop using gas.
I am intellectually attracted by the efficiency of the ones that produce heat and cool at the same time.
But it may be impractical–they are not really aimed at residential users.
And even if it works, it might not ever pay back if I don’t use it enough.

So, the two options for me are
(1) Leave the separate air con system as is. It works, though it’s very old and will die at some point.
Replace the gas boiler with a high temp heat pump system that produces DHW, high temp hot water for radiators, and lower temp hot water for under-floor hydronic heat.
Something like the LG Therma V line or something.

…or…
(2) Toss the existing air con central unit (keeping the chilled water circuits and fan/coil units).
Replace that with a simultaneous heat/cool heat pump system that produces all my hot and all my cold water.
Something like the Aermec NRP line.

Or, of course, do nothing and hope the gas supply isn’t a problem.

But back to your suggestion–around here, if I were smart I’d do thermal solar, not PV. It is very sunny here even in winter.
The problem is that the distances aren’t convenient–the roof I would put it on is pretty far from where I need the hot water.
And I’m a sucker for technology.
I could probably complicate it by taking the medium-hot water from the solar thermal in winter as input to a smaller heat exchanger to do the temperature boost I’d need.
But none of that helps with air con.

My favourite recent geek tech for air con is a radiative film that gets colder if exposed to the sky…even in full sun.
It has fancy layers that cause it to radiate at a wavelength (8-13um) at which the atmosphere is transparent.
You can run water pipes along under it (and thence to a small chiller) to create, in effect, solar thermal air con.

Jim

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#24

Aermec NRP line as an example.

Yeah, sounds neat. Although, as you say, the smallest unit is 12 tons. Where we are, mid-south, a typical residential heat pump is 5-6 tons. That’s what we have. Some of our neighbors have 2-unit systems, I guess if the house floorplan is spread out such that it’s better to have 2 zones. Those aren’t 6 tons though, they are more like two 3-ton units. One 6 is cheaper than 2 3’s.

However…heat pumps only work down to about 40 degrees outside air temperature. Below that it has to use supplemental electric heater coils. Large parts of the US are colder than that for months at a time during winter.

#25

“Our spot”? Does that mean you bought? Or holidaying and renting the same place as years ago?

With Covid restrictions finally lifted we spent a month in the rental we have been going to for 14 years. It has proven better to rent and keep our money in BRK. Current prices in France are pretty good relative to the USA, so it we are always considering that if economic and political situations change we might head to Europe full time.

Probably we have procrastinated long enough for the slowdown in the US real estate market to close that window. We will definitely be back in Europe in the spring, and a combined France/Portugal tour is a likely plan.

#26

However…heat pumps only work down to about 40 degrees outside air temperature. Below that it has to use supplemental electric heater coils.

That seems perhaps to be old expectations? Most of the systems I’ve looked at lately are way better than that.
This one produces its normal maximum 55C water at ambient temps down to -5C, and manages 40C water at exterior temps down to -15c.
(produces 131F water at temps down to ambient 23F, and 104F at temps down ambient 5F)
The more budget heat pumps produce much lower temp water, which won’t drive ordinary radiators or manage hot tap water.

Around here it’s below 5C way less than 1% of the time, so I’m not very worried about winters.
They way things are going, I’m more concerned about the ability to produce 7C water for the air con at ambient temperatures over 40C.
They say it can do that 7C goal with ambient up to 46C (115F).

Then you get into the ones using CO2 as a refrigerant…the problem is the water comes out so hot you have to cool it down to use it for anything.

Jim

2 Likes
#27

“ They say it can do that 7C goal with ambient up to 46C (115F).”

115 F is a bear.

#28

“ They say it can do that 7C goal with ambient up to 46C (115F).”
…
115 F is a bear.

I assume so.
I’ve survived -43C, and I hope never to see +43C.
It seems likely my wishes will not be met.

Jim

As one American friend from Arizona put it so memorably:
“Dry heat my ****, 120 is like climbing into an oven set on low”

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#29

They way things are going, I’m more concerned about the ability to produce 7C water for the air con at ambient temperatures over 40C.
They say it can do that 7C goal with ambient up to 46C (115F).

I’m a little surprised that nobody mentioned geothermal in connection with heat pumps - much less extremes of temperature than ambient. In Ireland certainly in rural settings, most domestic heat pumps are set up with a geothermal source. Perhaps in cities (like Monaco) this is not an option although, check this out for vertical geothermal https://celsiusenergy.com

StevnFool

#30

I’m a little surprised that nobody mentioned geothermal in connection with heat pumps - much less extremes of temperature than ambient. In Ireland certainly in rural settings, most domestic heat pumps are set up with a geothermal source. Perhaps in cities (like Monaco) this is not an option although, check this out for vertical geothermal https://celsiusenergy.com

I had sticker shock when I priced a ground source heat pump. I suppose it will eventually pay off for most installations, but it can take a long time.

1 Like
#31

I’m a little surprised that nobody mentioned geothermal in connection with heat pumps - …

Nice approach many places, but (to oversimplify) no ground water here so I didn’t consider it.
Not an easy solution on the side of a rocky mountain.

There is ground water near by, of course…the Med.
Monaco is currently building a seawater heat pump system for municipal heating and cooling, and running a network through the streets.
That works best with deep seabeds near a densely populated shore…check.
For example, using the air con network costs €16.87 per MWh of cooling you use. Plus 20% sales tax.

Jim

1 Like
#32

“Nice approach many places, but (to oversimplify) no ground water here so I didn’t consider it.”

Closed loop geothermal doesn’t need groundwater. Sufficient depth cools the liquid in the closed loops.

I had geothermal with this approach and the vast majority of the cost was to drill 5 loops.

in 2010 when I had it installed, the US tax code gave me a 30% tax credit.

I know that won’t help much in Monaco :wink:

#33

Tap water is pretty cool even in summer. Has there been any attempt to circulate it inside the house for cooling before running out to faucets and toilets?

#34

I’ve survived -43C, and I hope never to see +43C.

I lived in the arctic for a while and experienced -55C and extended periods of -45C. Where I live now it often gets over +40C.

Now that I’m old, I guess I’d rather have the heat.

#35

Tap water is pretty cool even in summer. Has there been any attempt to circulate it inside the house for cooling before running out to faucets and toilets?

This is, in effect, how the buildings in downtown Toronto are cooled.
They draw cold water from the bottom of the lake for drinking.
But before it goes to the water supply, they use it for chilling.
They are lucky to have a big cold deep freshwater lake right near the population density.

Jim

#36

Closed loop geothermal doesn’t need groundwater. Sufficient depth cools the liquid in the closed loops.

Yeah but…rock : )
You’d also have to go pretty deep to get to cool levels depending on the geology.
Picture a very steep south facing rocky slope in a hot climate.

A friend near here has a place around 300m from the sea, elevation about 150m above sea level.
His well went down about 250-300m before he hit water, well below sea level.
But it’s fresh water.

Jim

1 Like
#37

Since they work by moving heat from a hot living room to a kitchen tap, the efficiency is quite astounding during the periods you need both.
Expensive, but (a) no gas bills after that, and (b) maybe there won’t be any gas.

That might not be one’s only goal-- much better for virtue signalling : )

#38

Expensive, but (a) no gas bills after that, and (b) maybe there won’t be any gas.

That might not be one’s only goal-- much better for virtue signalling : )

Might be good for plain old ‘virtue’, too, especially since it’s essentially invisible to other people…

dtb

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#39

Tap water is pretty cool even in summer.

Lucky you. Our tapwater is warm enough to take a bath in.

Has something to do with the rocky ground (they had to BLAST a trench deep enough for the sewer, and drinking water pipe cannot go in the same trench as sewer water) – our water line is not quite 12" deep.
And it’s 550 feet from the street to our house, so plenty of time to pick up the summer heat.

OTOH, in winter the tapwater is refreshingly cold.

#40

Of the 40 posts on this thread, only 4 are related to the original post. :slight_smile: The original post itself is OT, and subsequent discussions are wayyyyy OT to the original post.

#41

Of the 40 posts on this thread, only 4 are related to the original post. :slight_smile: The original post itself is OT, and subsequent discussions are wayyyyy OT to the original post.

Thats the beauty of this board, that it sometimes can be like teatime for old ladies. Just meeting and chatting, communicating, without ideology, without fighting, insulting and posts pulled. Isn’t that great?

Btw: I’ve heard sometimes even financial matters are discussed. So all is good :blush:

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