This is the hottest part of the year, and my underground bunker is keeping it’s cool:
The ragged sort of sine wave line was the outdoor temperature over the last 24 hours. The other lines are the temperatures of the rooms with thermostats in them. There has not been any artificial heat in weeks and never any cooling. The bedroom is a little warmer that Barb likes for sleeping but I think if we opened two windows at night and put fans in the windows, we could cool the bedroom down to her ideal of 66 F.
The humidity varies from 45.2% to 53.3% That’s near ideal.
That’s some thoughtful design and good construction!
Having the surrounding thermal mass how you like it is a boon.
When the surrounding thermal mass is not how you like it, you need a lot of energy to re-tune it. OR, you open the window for temporary increase/decrease.
I’m frequently reminded of what permafrost means: a depth of soil, at a particular location, where the temperature never gets above 0C because by the time the heat pulse from summer arrives, it’s chased by the cold pulse from winter. Take that and make it a perma-habitation: Temperature is always 20C/68F on the nose. That’s a well-tuned underground bunker/hobbit hole.
The yearly deep earth average is about 51F. I expected I would need to supply some heat all year long. That has not been the case. The lights, electronics, water heater, refrigerator, freezer, and standby power of the other appliances have been sufficient to keep the temperature in the proper range.
I know I also inadvertently ignored the solar contribution to the exposed south facing conventional concrete block wall. I assumed only air conduction and ignored the radiant contribution. When I realized this, I became worried about needing to cool it in the summer. I think it is going to be okay.
If needed, I can also play games with ventilation. Currently, it is running 24/7. I could turn it off for a few hours during the hottest part of the day.
“…exposed south facing conventional concrete block wall.”
A summertime “false panel” a few inches away from the wall would shield it from solar radiation, still allow air circulation along the wall to prevent moisture accumulation. Probably, the entire wall does not need to be shielded, just a reasonable precentage of it.
The trick would be to make it inexpensively, very easily attached and detached by one person, secure during storm conditions, and low maintenance overall.
In Florida – where summer is 11 months long – it’s common to see solar screening on west-facing patios and large expanses of due east and due west glass- pull down like a window shade, latch it, when the sun drops (or rises) far enough, raise it. Some installations are motorized, and I’d guess timer-controlling it would be simple. It still allows some amount of light to pass, so while impeding unrestricted vision, it’s not a complete blackout.
The stuff is available in different shielding densities – 50% to 90% – and various colors. I’d expect that only some reduction in solar gain, and that only for a limited period of time, would be necessary; maybe 50% for three months might do it.
An underground bunker…. with windows?
Building/fire codes and my wife likes the view: https://www.joehuffman.org/NewHome/20200703_1SiteSelection.jpg
No problem. A hinged overhead awning/shutter made with layers of steel and concrete (ballistic and radiological shielding) that can be locked down from inside eliminates most of the shortcomings of “window in a bunker”.
I thought of and sort of planned for it. But it had to be custom-built and expensive. I settled for metal roll-up shutters.
The opening of the shield in case of fire and no electricity problem increases the complexity, space requirements, and expense. But if I decide I really need it, I could still add something like that.
I hate you just a little bit more, every time you post about that sweet bunker that i can’t have. #jealous
R
You can’t have mine, but I can put you in touch with the architect if you want. They are based in Colorado and do these types of buildings all over the country.