Ventilating a 1 1/2 story house.

[D_W]

An excellent source of coolth is the ground beneath us. A couple of feet below the surface here, the temperature is 8'ish to 11'ish C all year round.

Besides stopping heat getting inside the building envelope to start with, and minimising the amount of energy required to cool the air within that envelope (with insulation and thermal mass and sun shielding (could be as simple as a verandah) - details like people use in the design of their buildings in really hot countries) e.g.

http://www.themajlisgallery.com/wp-content/uploads/2010/07/The-Majlis-Gallery-3-Org-Size.png
I think moving air through the ground before bringing it into the house would be better than air conditioning - like this, perhaps:

https://geothermal-energy-journal.springeropen.com/articles/10.1186/s40517-018-0097-0
Of course, the OP doesn't have the luxury of re-designing/re-building their house! Cross-ventilation (both from side-to-side - during the day - and top-to-bottom - at night) and sleeping downstairs are two quick, easy and cost-free solutions.

Don't forget the cooling effects of plants and water too.

It may be different there than here, but in the states, the challenge in getting at that lower level coolness (it's about 50-55F here) or heat in the winter is getting it without mold and condensation problems. There was an old tradesman on another US forum who described something to me (i didn't completely follow it) as being a pass through of air underground and back up, and he said it worked well. he lives in either VA or TN in the US (both are very hot).

Challenge 2 is that if too much load is put on a segment or mass of earth underground, it will just come closer to the temp of the air being passed through it.

I know nothing about geothermal but expect that what happens is the well is drilled, something that will allow the ground adjacent to the well to absorb heat is installed and the piping runs through that (and whatever they require for mass is probably a good starting point for an estimate).

Or you can go all out as some have done where I grew up and build a house that's actually underground except for the top foot or so. There was one where I grew up - not sort of part of the way underground or built into a hillside, but with all floors underground. The owner said that was a cheaper way to build and own per square foot.

 

[D_W]

I think you are saying that the external thermal mass is a buffer and will reduce the extremes of range of temperatures reaching the inside face?

This is the case. My parents' home is a summer home from a wealthy quarry owner, so cutting stone isn't an issue. The windows are inefficient (but with storm windows on, they're OK). However, the walls of the house are 16" thick granite and there is some tree cover.

If you keep the house closed during the day in the summer, temps on the lower floor get above 80F only about 5 days a year in PA, USA. Those days would be bright sun and temps in the upper 90sF.

I suppose due to the volume of stone that this isn't a particularly economical way to do things, but for a quarry owner, no big deal. I would also suppose that this could be done with something much less expensive than cut granite rock and made even better due to real insulation, which I'm sure their house doesn't have - it's just stone, a small wall space of hardwood 2x4 and lath/plaster.

 

[mikej460]

We live in an old stone cottage with vaulted bedrooms and dubious insulation. The 400 year old part stays cool in summer but the more recent extensions (70s/80s) suffer from heat build up upstairs that make sleeping impossible during a heat wave. We've experimented with lots of different ways of cooling the hotter rooms down and the only thing that works is shutting out the sun during the day then opening all windows and doors front to back once the outside has cooled in the evening. But this depends on air movement and when there is no wind this tactic has little effect. I've now, after 3 nights if broken sleep, bought a portable ac unit from Machine Mart and installed it in our bedroom. It's great.

 

[MikeJhn]

People who live in the Med/South of France had it right a long time ago, during the day windows open and shutters closed, hence why the windows open inwards, problem is you walk around in the gloom inside all day, but that should not be a problem as you should be outside, my own place in France has 650mm stone walls and is always at about 20deg under the outside air, even at 40deg externally, the stone just does not seem to heat up.

 

[Rorschach]

My office is now under 24C!
Finally had the combo we needed of a prolonged cool period and a decent breeze, the cycle is broken, for now.

 

[mikej460]

Woke up a but chilly this morning and it was still 24C in the bedroom! I guess that despite my complaining about the heat everyday we do adjust..

 

[Rorschach]

Woke up a but chilly this morning and it was still 24C in the bedroom! I guess that despite my complaining about the heat everyday we do adjust..

By the time I adjust to the heat it starts getting cold and by the time the cold has stopped making me miserable, spring is around the corner

 

[Woody2Shoes]

It may be different there than here, but in the states, the challenge in getting at that lower level coolness (it's about 50-55F here) or heat in the winter is getting it without mold and condensation problems. There was an old tradesman on another US forum who described something to me (i didn't completely follow it) as being a pass through of air underground and back up, and he said it worked well. he lives in either VA or TN in the US (both are very hot).

Challenge 2 is that if too much load is put on a segment or mass of earth underground, it will just come closer to the temp of the air being passed through it.

I know nothing about geothermal but expect that what happens is the well is drilled, something that will allow the ground adjacent to the well to absorb heat is installed and the piping runs through that (and whatever they require for mass is probably a good starting point for an estimate).

Or you can go all out as some have done where I grew up and build a house that's actually underground except for the top foot or so. There was one where I grew up - not sort of part of the way underground or built into a hillside, but with all floors underground. The owner said that was a cheaper way to build and own per square foot.

I think your first point is about managing ventilation - and sources of excess humidity (washing/cooking) - properly.
Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.

Here are a couple of examples from the US using the ground as a source of both heat and cool - collected by cirulating air underground:

 

[artie]

we do adjust..

Remember 10 or so years ago we had that really cold spell. It was down to -18 at one point.

I remember going out one morning thinking that's a nice mild one, when I got in the car the gauge said -6

 

[Blaidd-Drwg]

Just finished insulating my pole shed and then installed a ductless mini split just in time for two weeks of high 90 degree Fahrenheit "spring" weather. It made a massive difference.

 

[Just4Fun]

Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.

We have a ground source heat pump. Our house is no Buckingham Palace but it is a big old draughty pile. When we installed the pump our supplier calculated that the largest off-the-shelf pump they offered would probably be big enough and their solution - rather than opt for a custom build (expensive) - was to put in the standard unit but size the loop in our field to be big enough to support 2 such units, and then put an extra pipe in the trench. The cost of the pipe was small compared to the cost of digging the trench for it. The theory was that if the standard pump proved to be too small it would be easy to install a second pump without having to dig up the field again. We have never needed a second pump, but having an oversized field loop was, I think, a good move. Plus if the field loop were ever to spring a leak we have a second pipe ready to take over.

 

[D_W]

I think your first point is about managing ventilation - and sources of excess humidity (washing/cooking) - properly.
Re. your second point - yes, apparently Buckingham Palace has a ground source heat pump installed (sounds inappropriate for such a big old draughty pile) but when on full blast can freeze the lake (quicker than it otherwise would)! I think that the answer is about sizing the heat/cool collector appropriately for the application.

Here are a couple of examples from the US using the ground as a source of both heat and cool - collected by cirulating air underground:

I'm such a perv for this kind of stuff that I've seen those before

I like the buckingham palace story! It still seems to me that in a world without social ridicule, there's something for nothing available in perhaps not totally uniform ways. For example, my house is brick, and the side that gets afternoon sun is partially brick and then a corner is stucco finished. The insulation inside the house isn't so great. There is zero chance that side of the house wouldn't heat all of our domestic hot water with something as simple as a black painted glass covered thermosiphon. The chance that I would ever get away with that is zero, but it would literally reduce the heat load in the house (or in the winter, more efficiently bring it inside) and heat the water, both.

It's in the blood:
https://www.motherearthnews.com/diy/fireplace-water-heater-zmaz78ndzraw
(that's a relative of mine - what's not that well communicated in that article in today's context is that article is 45 years old - once airtight stoves became the norm here, they replaced this setup).