The relevance is that someone spent 45 years, as a trained adult engineer no less, not 45 years merely breathing, aware of a problem and only after than much experience, solved it.
It would also be interesting if they had been a 1 year engineer or not an engineer at all, just for different reasons.
> He is enjoying his sauna 4-6 times a week. Instead of watching the “idiot TV”, Malcolm has spent his evening watching his thermal meters in his hot room.
One would not use the present continuous tense in that context as much as in that sentence.
A 10 year smoker may or may not also be a 10 year old smoker, but probably not.
A 6 month project may or may not also be a 6 month old project. Etc etc.
I wish they'd explain the problem in a short sentence before diving right in. Maybe this blog is for people who already know what the issues with an electric sauna are... bad ventilation, I assume.
> In my simple mind, the Finnish Sauna is just a type of Heat Treat Furnace or Oven that you load humans into and try to provide them with three characteristics. (1) not oversaturate their lungs with their own Carbon Dioxide waste products from being enclosed in a sauna with poor ventilation and limited fresh air volume changes (called Air Mixing in the study), (2) create an enjoyable Temperature distribution within the sauna environment (called Temperatures in the study) and lastly (3) provide a well distributed Ladled Steam Humidity cloud throughout the Sauna (called Air Condition in the study). Basically, everything you would expect for a good Finnish Sauna experience.
The rest of the article explains the ventilation needed for this.
I don’t see the problem defined well in the article, but it can mostly be surmised from the intro:
> Malcolm has analyzed the Finnish 1992 sauna ventilation study profile, applied his knowledge and experience as a 45 year engineer to test and better understand sauna ventilation in his own backyard sauna.
They wanted to test and understand the sauna ventilation in his backyard sauna and used a 1992 research paper as a reference. I can only assume this venture started because they were dissatisfied with the ventilation in their backyard sauna.
If anyone is interested in more information about sauna design in general, Trumpkin's Notes are by far the most referred to guide out there. [1]
There are also new products [2] which help improve saunas which are not ideally designed or where there are constraints (ceiling height mostly) to deal with.
1: https://localmile.org/trumpkins-notes-on-building-a-sauna/ 2: https://saunum.com/en/
I’m looking to spend about 1500, if you were to upgrade your situation while having a slightly large shoe string budget, any leads ?
I have no plans on upgrading so I haven't put any thought into it. A causal search revealed this in your price range [0] but I don't know anything about it. Don't forget that you'll likely need to pay for an electrician to upgrade your home circuit.
For me if I were to upgrade, it would be first be to get a better heater. The thermal foil + sleeping bag is surprisingly effective, though obviously I can't practice Trumpkin's advice on doing hot-cold-hot-cold-hot cycles easily without a door. It currently takes about 10-15m to get up to temp. So if you were on a smaller shoestring budget, I do think my thermal foil + sleeping bag build would save you a _lot_ of money on wood. I built a small (4x4x4) wood cube to sit in (you can see its base in the photo) but it leaked so much air that my DIY heater couldn't keep up. So I went with the thermal foil, which has all kinds of advantages... but it's certainly an eyesore :) A more powerful heater (with the appropriate house circuit) would make a small DIY wood box viable again. I think I _could_ recommend my jank build for others if they used a heater that wasn't DIY.
I still wonder when my DIY heater is going to kill me. I've since covered it with ceramic and wood so I'm no longer worried about 3d degree burns from fainting or whatever. And I use a GFCI outlet so any shock won't kill me. And I literally unplug it when not in use so it won't do anything unexpected. My thermal foil is _flammable_ though... which I found out when my heater started sparking. A better heater won't do that - but still...
Honestly, depending on your situation, it might just be better to save for a "real" sauna. For me time and money are currently at a premium, so I likely won't upgrade for years.
[0] https://se.kristo.shop/products/240064176624-17?variant=4064...
that's what she said
That being said, almost any real implementation in a cold climate place like Finland would have a heat exchanger at the building level for a mechanized ventilation system. It's of course still not 100% efficient so the circulation system within the sauna still works.
Handling this level of possible condensation might need additional considerations.
As the other commenter said, nowadays sauna in Finland is usually inside your house and the mechanized ventilation is connected to the overall ventilation system of your house. Hence the original article[1] explored the optimal positioning for mechanized air in/outlets in a sauna. The current Finnish building code incorporates the recommendations from this study (as document RT 91-11260).
I guess you could apply the same principles to an electric sauna in a separate building. Just use two fans (one pulling, one pushing) instead of an AC system. Most often a separate sauna building in Finland however has a wood-fired stove, which doesn't need as much consideration for ventilation as an electric sauna. My understanding is that the wood-fired stove itself creates a strong continuous draft which takes care of ventilation in the sauna room (pulling fresh air from outside through the stove and by combustion into the chimney).
[1]: https://publications.vtt.fi/pdf/tiedotteet/1992/T1431.pdf
FWIW current finnish building code more-or-less require a heat exchanger in the exhaust air flow. It didn't in 1990.
The combination of ventilation and heat source along with water poured on to the source is a way to regulate and adjust the temperature. The goal isn’t to trap as much heat as possible because having some of the heat flow out is key to regulating temperatures.
So, not really an obvious improvement at all.
Rather to get old air out and fresh one in. Temperature regulation is done by more or less heating, or if all fails, opening the door.
I have a barrel sauna with a Harvia. I take my phone in all the time. One level only. Where my head is, is where the thermostat is. When the temp says 170F the phone which is maybe a half meter below my head will almost never overheat. At 190F it will overheat eventually. Usually around 15 minutes or so. The higher I hold the phone and the less I insulate it the faster it overheats. “Overheat” in this case simply is the iPhone warning that it is getting too hot. I have the most recent iPhone SE at the time of this writing (2022 iPhone SE)
There’s no danger to the phone whatsoever. The phone is very good about protecting itself. Outside of the heat warnings it cools down and functions normally afterwards. The only real problem is the annoyance of not being able to use the phone in the sauna because Apple is a little overprotective of the device.
I would personally not call regularly exposing lithium ion cells to 170+ degrees F “safe”.
Why do you think those protections are there?
This ensures: 1) quick heat up of fresh air 2) vertically uniform heat 3) creation of better steam
http://localmile.org/proper-ventilation-for-electrically-hea...
I've gained an understanding, at least.
Maybe it's hard keeping a co2 monitor operating in humid sauna conditions, I dunno.
Also, given that many saunas are not airtight, I wonder what a steady state CO2 concentration would be. It may be high, but not dangerous.
