[HN Gopher] A 45 year engineer clears up electric sauna ventilation
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A 45 year engineer clears up electric sauna ventilation
Author : jmacd
Score : 180 points
Date : 2024-03-02 01:52 UTC (21 hours ago)
(HTM) web link (www.saunatimes.com)
(TXT) w3m dump (www.saunatimes.com)
| kken wrote:
| Why is the age of any relevance here?
| lmpdev wrote:
| 45 year not 45 years old
| because_789 wrote:
| Is he 45, or has he been an engineer for 45 years? Either way,
| I wish I had this guy's sauna.
| vikaveri wrote:
| If his sauna is the one in the picture, it has a flaw.
| Benches are placed too low. Your feet should be approximately
| at the level of the top of the stones. The sauna looks
| similar to a barrel sauna and they often are too low due to
| curvature to allow placing benches high enough
| givemeethekeys wrote:
| Because, he's FORTY FIVE! He's FRAIL with one foot LITERALLY in
| the GRAVE!! j/k. Someone mentioned that he has 45 years of
| experience. That makes him closer to 65. If he's still doing
| cool shit, thats pretty cool.
|
| 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.
| gifvenut wrote:
| If you read the article, the problem is explained quite well:
|
| > 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.
| jaktet wrote:
| That's not an explanation of the problem though, those are
| just characteristics of a good sauna.
|
| 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.
| Brian_K_White wrote:
| 45 year engineer, not 45 year old engineer. It's not about
| their age but their experience.
|
| 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.
| 2-718-281-828 wrote:
| what kind of engineer? software engineer? ;D
| OJFord wrote:
| Fwiw it didn't read naturally to me either. I suppose I'd say
| 'an engineer of [or 'for'] 45 years'. Or 'Malcolm, 45 years
| an engineer, [...]'.
| chrispeel wrote:
| In what part of the world is it typical to say "45 year
| engineer"? I'm an engineer in the western US, and would say
| "an engineer with 45 years of experience". I interact with
| lotsa international english; this one is new
| renewiltord wrote:
| I have definitely seen that before. In any case, despite
| the website being owned by an American, the language is not
| common American English:
|
| > _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.
| Benanov wrote:
| I enjoy reading articles (even if this one felt like it had been
| translated slightly clumsily) where scientific rigor has been
| applied to something mundane.
|
| I've gained an understanding, at least.
| adrianN wrote:
| Am I reading this right? Is there no heat exchanger in the
| ventilation? That seems like an obvious improvement.
| vesinisa wrote:
| The ventilation within the sauna is actually more effective the
| greater the temperature gradient between the entering low-CO2,
| cold air and the stale, hot air in the sauna. You want the
| entering air "falling" on the stove because it's colder i.e.
| denser than the surrounding air. It then heats up and mixes
| with the hot air in the sauna.
|
| 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.
| Ekaros wrote:
| Also to remember is that amount of moisture added in usual
| sauna session is not insignificant. Throwing at least couple
| of litres of water on stove is entirely normal in addition to
| whatever is perspired.
|
| Handling this level of possible condensation might need
| additional considerations.
| Thorrez wrote:
| What does "at the building level" mean? Is the sauna only
| part of the building and not the whole building? The article
| says it's a backyard sauna, which to me sounds like the sauna
| is the whole building.
| distances wrote:
| Can't speak for this article, but an electric sauna in
| Finland is almost always inside the building/apartment,
| accessed via the bathroom. A separate sauna building would
| have a wood heated stove.
| Maxion wrote:
| I'm not really sure what you're critizisng? This was a study
| done in the early 1990s looking at what would be the best way
| to build a sauna. This isn't a study in HVAC optimization for a
| house.
|
| FWIW current finnish building code more-or-less require a heat
| exchanger in the exhaust air flow. It didn't in 1990.
| Aurornis wrote:
| A sauna is a small, enclosed area with an extremely high
| moisture content that is only used for short periods of time.
| The expense of a heat recovery ventilator that could work with
| this extreme level of moisture wouldn't even come close to
| recouping any potential cost savings.
|
| 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.
| lukan wrote:
| "The goal isn't to trap as much heat as possible because
| having some of the heat flow out is key to regulating
| temperatures."
|
| 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.
| SoftTalker wrote:
| Dry saunas are a thing also. My gym sauna is dry except for
| the humidity provided by the sweating people sitting in it.
| They prohibit putting water on the rocks.
| xenonite wrote:
| tldr: place air inlet above the heat (B); air outlet on the other
| side at the floor (D). See figure: https://www.saunatimes.com/wp-
| content/uploads/IMG_6556-1-560...
|
| This ensures: 1) quick heat up of fresh air 2) vertically uniform
| heat 3) creation of better steam
| Maxion wrote:
| I wonder if this holds true for a wood burning sauna too? An
| active fire in the stove creates a massive draft that'll pull
| air through the stove and out the chimney.
| falserum wrote:
| Where I live, saunas have the stove's inlet outside the sauna
| itself.
| mikeyouse wrote:
| Yeah the only way for wood stoves to work ~decently in a
| small room like that is to be direct vented.
| jmilloy wrote:
| No it's different for wood burning when inside the space
| because they act as an effective exhaust on their own.
|
| http://localmile.org/proper-ventilation-for-electrically-
| hea...
| FionnMc wrote:
| Some additional discussion on Reddit
| https://www.reddit.com/r/Sauna/comments/1b2skn6/a_45_year_en...
| jmacd wrote:
| The sauna design rabbit hole is a very deep one.
|
| 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/
| 2-718-281-828 wrote:
| what is some crazy sauna fact?
| Permik wrote:
| In Finland sometimes we take advantage of the heat and we
| cook sausages on our sauna stove by wrapping them in aluminum
| foil and placing them on the hot rocks. You can still take a
| sauna normally and afterwards you have a cooked sausage to
| eat!
| Moru wrote:
| Our relatives always had a nice big piece of meat in there
| when we visited. Ofcourse they had at least three different
| saunas on the yard. The smoky sauna was mostly used for the
| cooking.
| dzhiurgis wrote:
| In Korea they cook soy-sauce-marinated eggs
| swagmoose wrote:
| been browsing r/sauna for years in the lead up to building my
| own sauna. Those trumpkin notes really are the key. It's
| unfortunate that the sauna industry has very few (if any) DIY
| kits that follow best practices for traditional saunas
| spiderice wrote:
| Just looking at those Trumpkin notes for the first time. As a
| North American, I'm very surprised to see that cedar should not
| be used. I always thought that was _the_ wood to use for
| Saunas.
| dharmaturtle wrote:
| Thanks for the links. I built my own super cheap (under $100)
| electric sauna, though I would _not_ recommend it for anyone
| else to copy. It 's lasted me about 4 years now though with
| about every-other-day-usage without burning down the house
| so... that's nice. I'll see if I can apply any of Trumpkin's
| Notes to my jank build [0]
|
| [0] https://news.ycombinator.com/item?id=28495062
| hoseja wrote:
| Thought it would be about heat exchangers.
| dharma1 wrote:
| I am actually typing this from a sauna with less than ideal
| ventilation (slightly ajar glass door) - need to cut vent holes
| to the sauna/house walls but haven't gotten around to it - so the
| timing is good. The main use of the ventilation is to not end up
| with too high CO2 concentration
| Aerroon wrote:
| Off-topic but I've been curious: how well do phones handle
| saunas? I thought the heat and moisture would pretty much be the
| worst environment for electronics. Is that not the case?
| throwaway11460 wrote:
| Not the one you asked, but I like to sauna in perfectly dry air
| more than in humidity. Also slightly lower temperature. As
| there is no humidity, the heat doesn't transfer as quickly. The
| phone doesn't get hotter than it does on a sunny day outside.
| vanattab wrote:
| At least in our sauna even in dry air my phone overheats and
| shuts down.
| renewiltord wrote:
| I read on my iphone's kindle app in saunas and steam rooms
| frequently. No problem.
| dharma1 wrote:
| Overheats pretty quickly, especially on the higher bench
| SoftTalker wrote:
| I have not noticed any venting in the sauna at my gym, but
| perhaps it's not obvious. It's a pretty big sauna, it will easily
| seat over a dozen people and people are coming in and out often
| enough that the door opening probably provides adequate air
| exchange.
| golem14 wrote:
| Wouldn't it be more practical to have a prominent CO2 monitor and
| only exchange the air (maybe by opening the door for a few
| seconds) if it CO2 gets too high ?
|
| 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.
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