[HN Gopher] Home Office Projects Series: Air conditioner setup
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Home Office Projects Series: Air conditioner setup
Author : gcds
Score : 137 points
Date : 2020-09-03 13:57 UTC (9 hours ago)
(HTM) web link (www.techprowd.com)
(TXT) w3m dump (www.techprowd.com)
| esaym wrote:
| I find it odd that for heat he only mentions units external from
| the a/c. The 'cu-229cf' unit he bought seems to be capable of
| heatpump mode[0]. Nonetheless, I really hate mini-splits. They
| always have really thin intake air filters that really don't
| filter anything. Thus the insides of the indoor unit are always
| caked in layers of dust and mold.
|
| [0]: https://panasonic.jp/aircon/housing/products/19f.html
| lxe wrote:
| I just did a DIY install of a mini split AC, including running
| electrical and the refrigerant lines, having never done so
| before. There was a whole "hidden side of the iceberg" to learn
| besides just the controller parts of how it works. The unit cost
| was ~600 while the install would have been ~1500, so I was
| betting that if I mess up catastrophically I could replace the
| whole thing once or even twice.
| miahi wrote:
| Did you use a vacuum pump for the refrigerant lines? If air is
| still inside the lines, the unit will not last as long - the
| problem is the trapped moisture that can damage the pump in the
| long run.
| zaroth wrote:
| Would love to read the write up!
| OnACoffeeBreak wrote:
| Did you have to get your work inspected? Where I live in the
| United States, the electrical lines would have to be inspected
| for compliance with building code, and I am not sure about the
| HVAC lines.
| bradlys wrote:
| Someone said Japan used to be in the title - and now that it
| isn't - I think it should go back. HN is mostly a US based
| website (with an emphasis on Silicon Valley). This methodology is
| wildly uncommon in the US. There's very little likelihood this
| kind of thing would happen in well over 90%+ of the USA.
|
| First off - if you're renting - you're not putting holes in the
| walls that go to the exterior and there certainly aren't any
| already existing. I've never seen or heard of that in the USA -
| particularly for apartments. Secondly - you're not hanging air
| conditioning units off the exterior walls of the apartment
| (rental or owned - you don't own/rent the exterior and ain't no
| residential building consenting to that shit). If you had a
| balcony, that's where it'd go, at best. Thirdly - where's your
| power coming from!? Most of these units are 220V and usually
| there is only one or two 220V power outlets in American homes
| these days and they're always dedicated to the washer+dryer.
| Maybe you have a third for an electric oven/stove. (Or an
| electric water heater) You'd have to run new power lines and that
| involves tearing up the walls. You could try to find 110V mini-
| split AC units but they're pretty uncommon in the USA (and much
| less powerful). As well, not having that AC on a dedicated
| breaker means you'll be giving up all other outlets on that
| breaker whenever the AC is on, which could be a lot of essential
| outlets in esoteric places.
|
| Great insight for someone who lives in Japan and someone who
| wants to see what it looks like to install AC in Japan. Put it
| back in the title!
| eropple wrote:
| Most of your points are very good ones, but one thing jumped
| out at me - in my experience, 12000 BTU 110v mini-splits aren't
| that hard to source, nor crazy-expensive, in the US. Super
| worth it, too, if you can manage it.
| outworlder wrote:
| > Most of these units are 220V and usually there is only one or
| two 220V power outlets in American homes these days and they're
| always dedicated to the washer+dryer.
|
| Meh. Only relevant if you need to pull more than 15A or so.
| There are plenty of portable air conditioners for sale in the
| US and most are happy with 110V and less than 15A.
|
| > HN is mostly a US based website
|
| This sounds like gatekeeping. There are lots of readers from
| all around the world.
|
| > Secondly - you're not hanging air conditioning units off the
| exterior walls of the apartment
|
| In the US. This is not particular to Japan. In fact, I'd argue
| that this is the most common air-conditioner setup worldwide,
| with building in many countries providing supports for either
| split systems or, more commonly, 'window' units.
| brendawalsh wrote:
| These minisplit units are typically, at least 9k to 12k BTUs,
| and if it a multi-zone unit it can be 24k or more.
|
| I have yet to see a portable AC in the US that is more than
| 12k btus and as quiet as a mini-split.
|
| Mini-splits are more popular now in the US, but, for whatever
| reason, the US is really into ducted systems.
|
| I never understood why putting an air duct in a hot attic and
| an air handler in a hot garage made any sense.
|
| You do have me curious on traffic stats for HN by country,
| though.
| perennate wrote:
| > many countries providing supports for either split systems
| or, more commonly, 'window' units.
|
| I think that's what GP was saying about the US -- while
| window units are very common, split systems are relatively
| rare. But anyway I think most of the article wasn't specific
| to a split system A/C unit, or even air conditioners in
| general.
| bradlys wrote:
| > Meh. Only relevant if you need to pull more than 15A or so.
| There are plenty of portable air conditioners for sale in the
| US and most are happy with 110V and less than 15A.
|
| You don't really know if people are happy with what they
| have. They just get what they get because that's all they can
| do. If your building outlaws window units, just because they
| have portable units - does that mean they're happy with a
| portable unit?
|
| > This sounds like gatekeeping. There are lots of readers
| from all around the world.
|
| American readership dwarfs every other country and region. It
| doesn't matter if there are "lots" of others when it's a US
| based website. YCombinator itself is mostly about investing
| in US based companies. Just look at the number it invests in
| in the US vs every other place.
| https://www.ycombinator.com/companies/ It isn't gatekeeping -
| I'm asking for someone to put in a more accurate title. After
| all - if I put "Rules of the road" up and it was Japan's
| rules of the road on an American website, it would be
| misleading. One would be expecting something relevant to the
| website they're reading it on (an American one!) while
| reading it but - instead - it isn't. Thus, bad title! It
| would be better to say, "Rules of the road in Japan".
|
| > In the US.
|
| How many times did I reference the USA in my comment? Five
| times. Guess I should have done six so that people wouldn't
| get confused about where I was talking about!
| perennate wrote:
| Most of the blog post was about reverse engineering the control
| protocol and automating the unit. The same principles could be
| applied to other A/C units, like window units that are
| ubiquitous in many parts of the US. It is not specific to split
| system, they didn't even install it themselves, that was a
| minor part of the blog post. Also, their methodology of writing
| their own software is uncommon anywhere, even in Japan; but
| that's true of many things that get posted here, that's what
| makes them interesting.
| nonbirithm wrote:
| > First off - if you're renting - you're not putting holes in
| the walls that go to the exterior and there certainly aren't
| any already existing. I've never seen or heard of that in the
| USA - particularly for apartments.
|
| This is allowed in my apartment. My closest neighbor cut a hole
| in the door leading outside and affixed an air conditioner to
| it, then made a setup of plastic bagging to make it lead all
| the way to their bedroom across the living space. In fact
| multiple other renters on the first floor did exactly the same
| thing.
|
| It's a relatively expensive place in Washington at around
| $2,200/mo market price.
|
| Or maybe I'm misunderstanding and the hole in the door existed
| before. I'll have to ask the next time I see them.
| boxed wrote:
| Just by luck before the pandemic hit I installed ground heat
| exchange with cooling for my house. This is so efficient the
| cooling is _free_. How do you ask is that even thermodynamically
| possible? Well all the heat from the cooling is used to heat the
| hole, which you get back in cheaper heating of the house from the
| same hole in winter. It 's amazing!
| calvinmorrison wrote:
| I like that the schematics are included on the air conditioner. I
| have a few older appliances like this that have it, and it has
| helped me a few times replacing/diagnosing parts.
|
| I laughed a bit where he explains about "Humidity" and the
| temperature. I know Americans are fat and lazy and love our AC's,
| but if you spend any time on the east coast, it's a giant swamp.
| Life is pretty insufferable without an AC when you are sitting
| inside all day working - and newer buildings are not designed
| with passive cooling in mind. I'd like to thank my forerunners
| for sucking it up but I basically keep my 3 window unit AC's on
| from June-Sept in Philadelphia.
| gcds wrote:
| I was more targeting Europeans with that paragraph as I never
| had any issues with it in Europe (UK, Germany, Lithuania)
| brudgers wrote:
| Pretty much every AC in the US has schematics somewhere behind
| a cover plate because field service by ordinarily trained
| technicians is a part of the equipment's life cycle. Basically,
| it's a safety issue (it might even be a UL requirement, I just
| didn't go that far down the google rabbit hole beyond the UL
| White Book https://legacy-uploads.ul.com/wp-
| content/uploads/2014/09/UL-...).
| 7thaccount wrote:
| In Louisiana and Arkansas (probably several other states), the
| temperature can get over 100 Farenheit with super high
| humidity. This leads to "swamp @$$" without copious amounts of
| AC. Being comfortable requires AC in the home, car, and at
| work.
|
| In highschool gym class we would just sit in the shade under
| the bleachers during the summer (too hot to do anything) and be
| dripping sweat everywhere back in class. It was miserable.
|
| It's just so miserable during the summer. The downside is that
| I'm only used to temperatures between 69 and 74 Farenheit, so I
| would be miserable in some place like Germany where they just
| live with the heat for a few weeks each year. I rented a house
| in Portland once without AC and it was during a heat wave. I'd
| douse myself in cold water, sit under the fan, and get very
| little sleep.
|
| A hurricane just hit Louisiana and the grid damage has been
| extensive (worst on record) so no power or AC. My mother's
| house is 85 degrees inside at night so she's sleeping in her
| office which is in a nearby town with power. I haven't seen the
| numbers yet, but typically a lot of elderly people die in these
| conditions without AC.
|
| The hurricane hit last Thursday I think and these are the
| current outages still in effect. Normally we would have power
| again in a couple of days in most non rural areas. The fact
| that it's been a full week and could be out for two more weeks
| is just unheard of.
|
| https://poweroutage.us/area/state/louisiana
| gowld wrote:
| What's amazing is that covid and politics at eso crazy that
| the hurricane gets nearly no news headlines.
| kijin wrote:
| We love to romanticize the past, when people supposedly did
| fine without energy-wasting gadgets.
|
| The oft-forgotten truth is that people in the past just died
| more. And still do, in many parts of the world that are
| surprisingly close to us.
| s0rce wrote:
| Heating buildings still takes more energy than air
| conditioning (usually much larger temperature
| differentials), people in the past used an enormous amount
| of energy on heating. They just consumed and generated the
| energy locally in the form of burning fuel, probably wood
| and coal instead of using an electric grid or natural gas.
|
| Also, I don't think A/C is any more of an energy wasting
| gadget than a heater. I can survive, moderately comfortable
| on a camping trip down to -10C, probably colder if I needed
| but I certainly wouldn't want my office/home to get that
| cold. Similarly, I don't want my house to be 30C with 85%
| RH.
| Scoundreller wrote:
| And are/were substantially less productive.
|
| When Singapore developed, the first thing the PM did was
| install A/C in all government buildings.
|
| https://www.vox.com/2015/3/23/8278085/singapore-lee-kuan-
| yew...
| dpeck wrote:
| As much as A/C is amazing, it's the lack of moving air that
| makes me the most uncomfortable. I've always been surprised
| at how much of Europe seems to have no interest in fans,
| ceiling or otherwise.
| vyrotek wrote:
| In Italy many are worried about "colpo d'aria" (blast of
| air) which they blame for all sorts of health problems.
| They also dislike ice in their drinks and think
| eating/swallowing some will hurt you too. I'm not certain
| whether the current generation of youth believe it or not.
|
| Source: Mother is Italian.
| bserge wrote:
| Ah yes, the draught, the European version of fan death :D
| baq wrote:
| at my latitude wind blows from the west 80% of the time. i
| can count windless days in the year on my fingers.
| dpeck wrote:
| That sounds really nice. Which latitude? Most of my time
| in Europe has been UK/Ireland/Netherlands/Belgium/Austria
| and in the summers I wouldn't say I'm often "hot" but it
| does often feel stuffy. Especially in bedrooms, and
| sometimes feeing that same way on warmer autumn days as
| well.
| baq wrote:
| 54N. just how the jet stream likes it.
| rsync wrote:
| Having individual heating and cooling units ( _per unit gas
| heaters!_ ) is stupendously inefficient.
|
| I travel in Asia fairly regularly so this isn't new to me, but
| even after all of these years I can't believe I continue to see
| shiny, brand new "high end" condo buildings in Hong Kong,
| Shanghai, Tokyo, Seoul, etc., with individual AC units hanging
| out the window.
|
| Contrast this with a condo in Minneapolis that I own wherein heat
| and AC are central in the building and individual units can set
| their temperature to whatever they like - all run with
| tremendously higher efficiency.
|
| It was explained to me once that there are Asian (specifically,
| Chinese) attitudes towards thrift that make it
| inconceivable/impossible to pay for AC that someone else might be
| using (or misusing). I don't know how true that is.
|
| What I do know is, my building in MPLS looks very nice without
| several hundred crappy boxes hanging out the windows.
| jonpurdy wrote:
| Others have mentioned the efficiency of cooling individual
| rooms instead of the entire home so I'll skip that. (Not to
| mention that in Korea and Japan, halls are considered
| "outdoors" and are not heated or cooled, which is a massive
| waste of energy for the few seconds that people spend in the
| hallways.)
|
| My issue is that any place I've lived with central AC (or a
| condo with a fan coil unit) is that when it's actually hot, the
| central units don't have enough capacity to cool my unit down
| enough and don't provide enough control. It's like the old
| cable modem congestion problem where the whole neighbourhood
| slows down during peak times.
|
| Heat is even worse; when buildings are heated centrally they're
| usually much too warm in the winter and I end up with my
| balcony door opened to let the heat escape. Vastly less
| efficient than letting me heat my own unit.
|
| By forcing people to heat and cool only their units as
| required, people either get the exact temperature they want, or
| will accept a non-ideal temperature and supplement with fans to
| save money.
| larrywright wrote:
| I've only been to one city in India (Chennai), but my
| experience there was that common areas are not air
| conditioned. Hotel and office hallways, public restrooms,
| etc.
| gcds wrote:
| I think it's more efficient to heat/cool single room than all
| house when for e.g. you spend most of the day in office/living
| room and then go to bed. That way you only have one AC running
| but of course if you have big family then it maybe makes sense
| but still... Those mini split AC efficiency is much higher than
| I have seen in US ducted systems (follow few channels) because
| mini splits uses inverter technology for higher efficiencies.
| bluGill wrote:
| That depends on insulation.
|
| If your house is well insulated it doesn't make much
| difference as the cooling needed for when you are in the room
| (assuming you use all rooms every day) is most of the cooling
| needed for the entire day. Thus you may as well temperature
| control everything at once and call it good. The loss of
| energy is more than worth it considering the comfort.
|
| If you have poor insulation the above doesn't apply.
|
| In extreem climates there is another consideration:you need
| to keep the entire building warm enough to keep the pipes
| from freezing. Here you keep everything warm because if the
| heater fails in one room there is a risk you won't enter that
| room until it is too late and you have done major damage. By
| having one central unit it is much more likely someone will
| notice before there is a problem. Extreme climates also tend
| to have better insulation which makes the central system more
| convenient.
| rietta wrote:
| Or you have to keep it cooled to keep the relative humidity
| low enough that mold and mildew do not take over.
| driverdan wrote:
| With a central chiller you can still have each room on a
| separate zone.
| edgarvaldes wrote:
| >attitudes towards thrift that make it inconceivable/impossible
| to pay for AC that someone else might be using (or misusing)
|
| Sounds somewhat similar to the opinion some americans have
| against free healtcare
| [deleted]
| ClumsyPilot wrote:
| When I moved to UK I was shocked that each house amd apartment
| (!) has a separate gas boiler, a device that need maintenance,
| takes up space, makes noise and regularly kills people with
| carbon monoxide. I then met a person who lost a loved one to
| that thing!
|
| In Russia and Czech Republic we have district heating, you just
| get billed for the amount of hot water consumed. Some of that
| heat comes from industrial sources or nuclear power-plants.
|
| Even where it's coming from a giant gas boiler, they can be
| efficient combined heat and power units. Ofcourse, some of that
| infrastructure is old, but a rich western country should be
| able to do even better.
|
| We'd only have a boiler in rural areas, to have them in
| apartments is just madness.
| jimbobimbo wrote:
| What's missing from the description of a district heating
| paradise in Russia (ex USSR really) are constant issues with
| hot water / heat availability throughout the year. It's not
| unheard of cities shutting down central hot water supply for
| months for maintenance, or breakdowns of central heating in
| the middle of the harsh winter. The further you go from
| regional centers, the worse situation gets. The temperature
| that you get in your apartment out of this system is also
| inconsistent, and depends on a variety of issues with aged
| infrastructure.
|
| My family lives in a relatively small town in Ukraine, got
| fed up with that and installed a gas-powered heater that
| serves both heating and hot water. This setup is 15+ years
| old already, never looked back. When the rest of the building
| is freezing cold, it just works.
| spockz wrote:
| District heating exists in the Netherlands as well. Even
| though it might be more efficient it usually is crazy
| expensive. I paid more for heating and hot water in my 90m2
| apartment in Utrecht with two of us where we almost never
| were at home than for our 150m2 house with two extra kids and
| being at home often.
| sergeykish wrote:
| I've definitely seen gas boiler/heater in city center
| apartment, Olomouc, Czech Republic.
|
| I am from Ukraine. While in theory district heating is
| awesome there are some problems in implementation:
|
| * every summer there is a three weeks period without hot
| water, a lot of people have electric boiler as backup, it is
| even bigger than gas boiler
|
| * no hot water in off peak time on upper floors of old
| buildings, have to flush some away, fixed with loop in new
| buildings
|
| * old buildings vertical heating pipes makes it impossible to
| bill apartment, no incentives for heat insulation (wall and
| windows) or reducing temperature, 25degC in winter is a norm,
| fixed with per apartment pipes in new buildings
|
| * a lot of heat escapes pipes, melted snow patches in winter
|
| * fixing broken pipe is messy, change of the pipes even
| worse, seen both
|
| * requires high level of participation - at least some small
| towns have no district water for 20 years, some even without
| district heating
|
| * modern gas boilers are 90+% efficient [1]
|
| Some new buildings have heating plants, looks like a better
| idea. But heating is a big part of CO2 emissions, stored
| hydrogen heating plant is a future. Even better if it is a
| power plant too.
|
| [1] https://www.theheatinghub.co.uk/boiler-efficiency-guide-
| and-...
| m0zg wrote:
| That's all wonderful until they shut off your hot water for a
| month for repairs. :-) Source: lived in Moscow for 8 years.
| Vastly prefer my 60 gallon boiler.
| reaperducer wrote:
| _In Russia and Czech Republic we have district heating_
|
| This exists in some cities in the United States, but it's
| usually older cities like New York and Chicago.
|
| The plus side, is that often if you have a building with
| district heating, you will also have district cooling.
|
| On a somewhat related note, some of the buildings in Chicago
| heat and cool themselves with water pumped directly from the
| Chicago River. Lake Michigan acts as a giant thermal
| reservoir. ("Cooler by the lake," as the TV weathermen say.)
| andechs wrote:
| Toronto's deep water cooling system is the largest in the
| world, and air conditions a good chunk of the downtown
| core.
|
| http://buildipedia.com/aec-pros/engineering-news/torontos-
| de...
| frosted-flakes wrote:
| Fascinating. I never knew that this existed.
|
| It's also interesting that it's also part of the city's
| drinking water supply:
|
| > The Energy Transfer Station includes large arrays of
| heat exchangers that allow the heat from the downtown
| chilled water loop to be rejected into the city's
| drinking water supply before distribution to the public.
| The heat removed from the downtown chilled water loop is
| therefore never transferred to Lake Ontario and the
| slight temperature increase is insignificant for water
| utility consumers.
| guerby wrote:
| In Paris there's even a cold water network:
|
| https://www.climespace.fr/en
|
| In addition to hot water since 1927:
|
| https://fr.wikipedia.org/wiki/Compagnie_parisienne_de_chauff.
| ..
| bserge wrote:
| Yeah but there is no such infrastructure in most of the UK,
| so it would be a big and expensive undertaking to build it.
|
| Individual gas/electric boilers are a pretty good solution.
| Maintenance isn't that hard, though legally you need a Gas
| Safe certified technician to do everything, and they're smug,
| expensive, slow, and not all that smart tbh. But because
| there's no competition you have to put up with that :D
|
| That was the most frustrating thing for me - I could do
| everything myself, but wasn't allowed to.
| ClumsyPilot wrote:
| For apartment blocks it's particularly silly because you
| can install a single device in the basement at the time of
| construction. Some newer blocks have it.
|
| UK housing stock is in desperate need of upgrades, most
| houses are literally bleeding money through the walls
| because of poor insulation, and because heatpumps are much
| more efficient that boilers.
|
| Consider that they are more economical when supplying
| several houses, pay for themselves over time and that
| interest rates are zero. It becomes obvious that we need a
| large-scale program of energy efficiency upgrades, it would
| create jobs during a recession and help address climate
| change.
| bobthepanda wrote:
| Prior to certified technicians people were dying of carbon
| monoxide poisoning after improperly installing or
| maintaining boilers.
| https://www.youtube.com/watch?v=0B_sgYnNEO4
| asdfasgasdgasdg wrote:
| I am not sure that it is true that split system ACs are
| substantially less efficient than central. And depending on the
| size of your unit and how much space you can leave
| unconditioned, it can save substantial energy to use a split
| solution. For example, we used space heaters during the winter
| in cali to save substantially on energy. This is because even
| with much less efficient electric heating, heating just two
| bedrooms at night is more efficient than heating the entire
| house. (We saved hundreds of dollars each winter despite that a
| btu from an electric heater costs two or three times as much as
| a btu of gas.)
| EricE wrote:
| Exactly - obviously the larger the home and more uneven the
| occupancy, the more the individual units make more sense.
|
| And you don't have to have one indoor unit per outside unit.
| Systems that can have one outdoor unit with up to four inside
| units are readily available.
|
| What's really wild is Mitsubishi's City system - designed for
| commercial spaces (or really large homes) you can have dozens
| of internal units. And more impressively, it can move heat
| around _inside_ the building. If you were having a party in
| the middle of winter and all the body heat was heating up the
| room where everyone was you could "AC" that room and then
| dump the heat elsewhere in the building.
|
| The key is the per-room zoning. Minisplits are by far the
| easiest and most efficient way to micro-zone. Also the
| elimination of loss from ductwork should not be discounted
| either; it's often very significant. Especially if you can
| eliminate ductwork from unconditioned space!
| L_Rahman wrote:
| This examples fails to account for the fact that radiant floor
| heating is a default feature in all new Korean homes.
| oehtXRwMkIs wrote:
| You mean mainly apartment units right?
| criddell wrote:
| The examples seem to mostly be looking at cooling and
| dehumidifying. What do radian floors for heating have to do
| with that?
| bluGill wrote:
| Heating the air drys it out...
|
| The article is about Japan. I would expect Korea has a
| different climate which means different considerations.
| (but I'm not an expert in climate)
| criddell wrote:
| > Heating the air drys it out...
|
| I'm not sure that's true. Hot air can hold a lot of
| moisture, the extreme example being steam.
| larrywright wrote:
| I think what is more true is that typical furnace designs
| remove moisture from the air that they heat.
|
| Most comfortable place I ever lived in, heating wise, was
| an old house that had been converted into apartments. It
| still had steam heat. I loved that.
| bluGill wrote:
| A furnace doesn't remove moisture.
|
| Steam heat is radiant which feels very good. Nothing to
| do with moisture added, steam heat is almost always a
| closed loop so no water is put into the air.
| bluGill wrote:
| This is complex...
|
| Hot air can hold a lot more moisture than cold air. (what
| you said). However when you take cold air and heat it the
| amount of water in the air doesn't change, while the
| amount of water than the air can hold did. When talking
| about water in the air the important part is how much it
| can hold relative to how much it does hold, not how much
| it actually is holding.
| marcinzm wrote:
| >Contrast this with a condo in Minneapolis that I own wherein
| heat and AC are central in the building and individual units
| can set their temperature to whatever they like - all run with
| tremendously higher efficiency.
|
| Is it more efficient? There is going to be loss as things get
| pumped across hundreds of feet even with insulation. The
| central system needs to run even if few units or not units are
| using it just in case. In Asia heating and cooling is done per
| room to the minimum as I understand it so "per unit
| temperature" wouldn't fly. And an in-room gas heater is going
| to be 100% efficient with no losses due to transmission.
| bluGill wrote:
| Hard to say. Many central systems are old an inefficient.
| However modern high efficiency systems require a water drain
| which rooms often don't have available thus most room systems
| are not able to get the best modern efficiency. Most houses
| in Minneapolis I used to live there) have a single furnace in
| the basement which can achieve just as much efficiency as any
| other central system.
|
| There also indoor unvented space heaters. They work and are
| very efficient. However they put all the combustion
| byproducts into the air, and thus really only useful in rooms
| that have a lot natural ventilation (tents for example)
| quickthrowman wrote:
| Generally (in a high-rise) the units are fed a steady stream
| of 'supply air' at 50 F or so, and heat pumps in the unit
| itself control the climate in the unit.
|
| HVAC needs to run constantly in these buildings as they're
| sealed and need airflow for air exchange.
|
| Air isn't heated and then sent thru the ducts in a high-rise
| building.
| novok wrote:
| Wouldn't a shared system with individual metering, which is how
| electricity works for the most part, work then in that case?
| l3s2d wrote:
| The bit about attitudes towards shared payments is fascinating.
| I wonder if this is truly attitude or just lack of choice.
|
| Are there any concrete examples of existing systems where
| people choose to pay more when the alternatives are
| significantly cheaper but pricing is shared?
|
| Hypothetical example scenario: Someone would choose to pay $10
| for their own water instead of $2.50 (on average, with minor
| fluctuations), in order to avoid subsidizing other tenants'
| water usage. The difference in cost could be attributed to the
| maintenance burden of many monitoring devices. I have a hard
| time believing anyone would choose the more expensive option.
| philwelch wrote:
| Human intuitions about fairness are not always Pareto-
| optimal.
| michaelt wrote:
| _> Are there any concrete examples of existing systems where
| people choose to pay more when the alternatives are
| significantly cheaper but pricing is shared?_
|
| American healthcare? :-p
| smileysteve wrote:
| This is not limited to Asian, single units are also common in
| European, and Central American cities; (likely buildings that
| existed prior to air conditioning ubiquity -- which also
| related to sealing of the home);
|
| Much of this is related to air conditioning attitudes as well;
| Do you need to have comfortable temperatures in the entire
| house or just a living room with comfort when working, watching
| tv, eating dinner.
|
| tldr; air conditiong views vary from necessary to an accessory;
| where they're an accessory, one of units are most common
| [deleted]
| falcolas wrote:
| All of those images look more like heat pumps, which are
| actually ridiculously power efficient, especially if you're
| heating/cooling the rooms individually (since you're cooling
| only the hotspots, not the entire house to handle one hot
| room).
|
| EDIT: The unit installed by the article's writer is an AC only,
| which is probably because the AC is cheaper than a heat pump.
| But a heat pump can both heat and cool, and are quite
| efficient.
|
| The Google term of use is "Heat Pump Mini-Split"
| gcds wrote:
| It is heat pump it can cool/heat just in Japan they don't
| call them heat pump. Plus it is inverter based so super
| efficient.
| falcolas wrote:
| Interesting. Odd, but interesting. Thanks!
| Spivak wrote:
| Whole building climate control isn't really the problem, it's
| that unlike electricity, there's not a good billing system
| attached to it like we have for eletric and gas.
|
| Other than "it doesn't exist yet" there's nothing fundamental
| about central air that precludes being able to bill individual
| units separately based on their usage. The fairest way for a
| group to pay for something isn't always diving the total cost
| equally among the group. Can you imagine if we did that for
| taxes?
| tantalor wrote:
| I doubt that. OP said "individual units can set their
| temperature to whatever they like"
|
| This implies they can turn on/off their usage. So you can
| install one electric meter per unit, which equally distribute
| the current load on the A/C, and turn the meters off
| (increasing load on other meters) when that unit is not
| consuming A/C.
| Spivak wrote:
| Whole building climate control doesn't mean all units are
| set to the same temperature! The discussion is specifically
| about a zoning hvac systems and billing for them.
|
| HVAC systems unfortunately don't work as nicely as you
| describe. You can't run the HVAC for just one unit,
| typically buildings are broken down into floors and either
| the system for the floor is on or off. This is how you see
| multi-tenant offices designed -- each floor is submetered
| and the cost is divided proportionally among the tenants on
| that floor based on square footage. The zoning works by
| controlling airflow in the ducts. So while your billing
| system is clever it would be absolute murder if you were
| the only one running AC/Heat and you would be much better
| off with a smaller individual unit.
| thaumasiotes wrote:
| > It was explained to me once that there are Asian
| (specifically, Chinese) attitudes towards thrift that make it
| inconceivable/impossible to pay for AC that someone else might
| be using (or misusing). I don't know how true that is.
|
| I don't know how true it is either, but I can provide some mild
| support.
|
| Several years ago a vicious heat wave hit Shanghai, and the
| subway stations filled with people taking advantage of the air
| conditioning. I asked a friend about this -- I don't see the
| subway station as a particularly nice place to hang out, since
| it's loud -- and the response was "they all have air
| conditioning at home, but they don't want to pay for it".
| bobthepanda wrote:
| I've heard of people doing this in malls, but subway stations
| is a bit weird for sure.
|
| Movie theaters in the US were very popular prior to prevalent
| home AC for much the same reason.
| thaumasiotes wrote:
| Malls are far away. Your local subway station is
| necessarily nearby.
| fulafel wrote:
| Insulation and ventilation cold/heat recovery is more important
| yhan central vs per room heat pumps.
| mattdoughty wrote:
| I used to live in a flat (I guess you would call it a condo in
| the US) with heating provided by the building. My landlord who
| I lived with left the heating on 24/7 during the winter and the
| flat would get ridiculously hot. Even though he was the one
| paying for it indirectly through service charges. This
| arrangement is becoming quite common for new build flats in the
| UK but I would actively avoid if I was looking to buy.
| jefftk wrote:
| _> tremendously higher efficiency_
|
| For heat, yes, but not AC. For example, the Mitsubishi MY-
| GL12NA is a very efficient mini-split with an EER of 13, but a
| random modern window or through-wall unit (ex:
| https://amazon.com/dp/B07D8R2V8H/) will have an EER of ~12.
| amluto wrote:
| > Having individual heating and cooling units (per unit gas
| heaters!) is stupendously inefficient.
|
| > Contrast this with a condo in Minneapolis that I own wherein
| heat and AC are central in the building and individual units
| can set their temperature to whatever they like - all run with
| tremendously higher efficiency.
|
| This needs some real data.
|
| There are a few central technologies that might be used. A
| condensing gas-fired boiler might exceed 95% efficiency if you
| imagine that losses in the hydronic pipes are minimal. An
| evaporative cooling tower has awkward-to-define efficiency
| because it consumes water, but I doubt it works very well in
| Miami. A giant air-source central heat pump might be reasonably
| efficient (COP around 4?).
|
| But little modern heat pumps with variable-speed drives (often
| marketed as "inverters") can be very efficient indeed. Fujitsu
| will sell you a unit right here in the USA with SEER 29 or
| better, and the general trend is that the smaller units are
| more efficient than the larger units. (Yes, SEER uses
| ridiculous units.)
|
| Additionally, in most markets, a reasonably efficient heat pump
| is both less expensive to operate than even a 100% efficient
| boiler and has lower greenhouse gas emissions.
| Melkman wrote:
| I know it's only one datapoint but recently we had four
| indoor airco units installed in our house for the bedrooms
| and livingroom. I expected a single outdoor unit. However
| during talks with the installer he advised us to go for two
| outdoor units. This was cheaper in hardware, a bit more
| efficient and way cheaper to install by placing one outdoor
| unit on the front of the house and one on the back so all
| rooms could be reached within a meter or so from the outdoor
| units.
| sgc wrote:
| For heat pumps more outdoor units is definitely more
| efficient, since the outdoor unit needs to be big enough to
| accommodate all connected indoor units at once, and will be
| on even if only one is in use. Two per unit is my go to
| trade off on that one, with an attempt to group together
| units that are more likely to be used at the same time (so
| no bedroom / living room split, try to stick with
| bedroom/bedroom and living room/dining room etc).
|
| BTW they have low profile indoor units that can be embedded
| flush with the ceiling or wall, so the bulkiness indoors is
| not even required anymore.
| PaulDavisThe1st wrote:
| those ceiling mount units ... not sized for typical US
| construction techniques, so installing them in an
| existing ceiling can be quite complex. If you're doing
| new construction, it is possible to correctly frame up
| the ceiling so that installing them becomes trivial.
| brendawalsh wrote:
| There are two kinds available currently for ceiling.
|
| The cassette, that would fit into a drop ceiling, and
| there is also a mini-ducted unit, installed in the
| ceiling with small-run ducted ports.
|
| My favorite are the ones that look like picture frames.
| rsync wrote:
| "This needs some real data."
|
| I agree and I, admittedly, have none.
|
| I will say, however, that a deeper dive into these
| efficiencies would _also_ have to take into account the
| production, distribution and installation costs (embedded
| pollution, not dollars) of several hundred little devices vs.
| a single plant that is integrated into each unit during
| building construction.
|
| Even considering room by room optimization (turning off AC in
| living room while you sleep, etc.) it's hard to imagine this
| penciling out vs. operating + embedded costs ...
|
| (and I still suspect that _just the operating costs_ are
| higher, but your point is well taken ...)
| saeranv wrote:
| At least one building science expert (Joseph Lstiburek)
| reccomends a decentralized approach for HVAC, with tightly
| sealed individual units: https://www.buildingscience.com/do
| cuments/digests/bsd-110-hv...
|
| Although I do wonder how that works with something like
| district heating/cooling systems, which seem to rely on
| centralized boilers and chillers to move thermal energy
| between buildings.
| brendawalsh wrote:
| I was gonna say, the outlay of capital for a building-wide
| hydronic system and an evaporative tower, versus each owner
| be responsible for their AC, I can see why that would be
| possible.
|
| Particularly if the building is older.
|
| Also, I am curious why there are multiple single condensor
| units in lieu of multizone units...I guess it is
| financially easier to purchase one unit at a time.
| jk700 wrote:
| A common form of central heating, like burning fossils kind
| that delivers hot water over insulated pipes to each
| building, is more efficient in pretty much every way and is
| cheap to add during building construction than doing it
| individually. But it's not the case with a "central AC",
| it's less efficient, more expensive to add during building
| construction and operating costs are no better. Just think
| about it, you can't just deliver cold over a pipe and rely
| on air convection, like with heat, you need to literally
| move cold air into each room and make it individually
| adjustable. It's a ridiculously inefficient complicated
| expensive system requiring extra space and with
| installation costs higher than that of all AC units
| individually installed.
| yourapostasy wrote:
| Make sure if you get a mini-split that you do the following
| around keeping the condensate drain mechanism going. I have
| yet to see a mini-split product manual/installation guide
| that gives detailed information on these operational issues.
|
| Many models let you run the condensate drain on your choice
| of right or left side. The unused side is often only supplied
| with a friction-fit drain plug. Over a period of many years,
| some of these plugs can shrink, not quite fall out, and then
| you get a real mess.
|
| Make sure the drain pipe is dry. Clean it with denatured
| alcohol, then let dry again.
|
| Buy a silicone sealant that carries a 20-year warranty. Buy a
| roll of "cork tape" [1]. Fill about 2.5 cm / 1 inch of the
| drain pipe with the silicone sealant. Stretch wrap the drain
| plug with the cork tape, so the tape thins out while sticking
| to the plug. Pinch/squeeze/roll the part of the tape that
| hangs out beyond the end of the plug so it is slightly
| smaller than the stem of the plug. Push the plug into the
| drain pipe, and try to push it all the way up to the head of
| the plug. The cork tape will fill out and adhere to the walls
| of the pipe. Finally, stretch wrap more cork tape (or self-
| fusing silicone waterproof tape if you don't like the
| stickiness on both sides of the cork tape) around the entire
| drain pipe and drain plug assembly, including wrapping the
| end, and seal up the assembly to the pipe.
|
| Mount a very slightly tilted metal shelf underneath the mini-
| split air handler (the part that mounts on your wall inside
| your building), and install an AC-mains-powered moisture
| sensor that cuts off power to the mini-split when triggered,
| at the lowest end of the shelf. Mini-splits usually use a
| zero-capacity drain pan to stay as slim as possible, and if
| they clog up at the condensate drain pipe, they overflow
| rapidly (within minutes).
|
| Learn how to take the plastic cowling off the unit before you
| mount it, document it by video or photographs, and stash it
| with your product manuals. Mini-split manuals usually don't
| show how to take them apart enough to get at the condensate
| drain, and most models I've seen have lots of plastic catches
| all over that are hard to see when you're standing on a
| ladder peering between the ceiling and the cowling. If you
| ever get biogrowth in it, you'll want to know how to take it
| apart.
|
| Or, if you don't want to take it apart to get at the drain,
| you can codge together a way to run your wet/dry shop vac to
| mount to the condensate drain and pull stuff out. I used a
| shop vac mini kit [2]. I also got a venturi-based device to
| try to develop more vacuum [3] with the CO2 tank I normally
| use to make fizzy water.
|
| [1] https://smile.amazon.com/DiversiTech-6-330-Cork-
| Insulation-B...
|
| [2] https://smile.amazon.com/Wet-Dry-Accessories-
| VT1215-Attachme...
|
| [3] https://smile.amazon.com/gp/product/B00CIRZGV6/
| hinkley wrote:
| I was a bit surprised he bought two condensers instead of one
| large one.
|
| I'm looking for a mini split currently and I found condensers
| with up to three separate coolant lines (although with the
| shape of my place. I might only be able to use 2 at once, and
| have to use a window unit on the other end).
|
| Unit size (especially width) goes up much slower than BTUs, so
| the main value of two seems to be cooling your house in
| installments, which he isn't doing.
| Scoundreller wrote:
| Lately new condo builds in Toronto will have an in-unit heat
| pump that fails within 5 years (and May or may not sound like a
| spaceship), with a coolant line going to a central unit that'll
| have a geothermal/auxiliary heating/cooling loop, that also
| tends to fail.
|
| All in all, a stupid system in practice. Only benefit of it all
| is that you don't have to wait for the building to change
| between heating or cooling mode.
|
| At least we tend to still have central hot water and don't
| meter water yet. Metering can make a lot of sense, but not when
| your account fee is $15-$20/month. Any reduction in use just
| means some rich dude goes on more jet vacations.
| bkovacev wrote:
| Why would it fail within 5 years? Isn't the usual lifespan of
| those pumps 10-15 years?
| sergers wrote:
| Is this really specific to Japanese air conditioners? Or is this
| really about mini-split ac that are manufactured around the world
| under many companies.
|
| I don't see whats specifically Japanese outside of the person
| using Panasonic and is in Japan.
|
| The person could be in the USA with Mrcool mini split, it would
| be a similar article.
|
| Edit: title has been changed to remove mention of Japan, so my
| nitpick may no longer valid:)
| agwa wrote:
| I've never seen an apartment building in the US with special
| pipes for running the refrigerant lines. It's just not feasible
| to install a mini split in the US if you're renting, but it
| appears Japan is totally set up for it.
| gcds wrote:
| Impossible to live without AC in Japan. Also almost every
| move company can remove/install AC's pretty easily so it's
| kinda convient.
|
| Also if all rooms already have installed AC's then apartment
| rent price is much higher than similar without it so it's
| 50/50 what you want.
| agwa wrote:
| It's the same in many parts of the US, but unless the
| apartment comes with central AC, we're stuck with noisy and
| inefficient window AC units[1], or worse, portable AC
| units[2].
|
| [1] https://www.mytrustedcontractor.com/wp-
| content/uploads/2025/...
|
| [2] https://www.lg.com/us/images/air-
| conditioners/md05186704/gal...
| driverdan wrote:
| > Impossible to live without AC in Japan
|
| Come on. People lived there for thousands of years before
| AC.
| sandworm101 wrote:
| Not in highrises. Not in megacities.
| dkarp wrote:
| He uses the Echonet Lite protocol[1] and says that it is a home
| automation protocol used in Japan. So that whole second part is
| Japan specific. I agree that the rest probably isn't.
|
| 1. https://echonet.jp/hems_en/
| phantom784 wrote:
| I wish those holes for refrigerant lines in apartments were
| standard in the US. My apartment in the bay area has no AC and
| furthermore doesn't allow window units, so I'm stuck with
| inefficient portable units. I'd love to be able to just put some
| mini-splits in (and I'd probably still come out ahead over
| renting a place that comes with central AC).
| djanogo wrote:
| Where are the refrigerant lines, how did they run them from
| compressor to evaporator?, I thought the biggest issue with AC
| self install is filling the refrigerant and sealing those lines.
| jabart wrote:
| Units come pre-charged now. My new central air unit was pre-
| charged at the compressor for 50ft of line. You need to still
| seal the lines to the unit which requires something hotter than
| a propane torch(acetylene), then you should purge the lines
| with nitrogen, have HVAC gauges to verify the pressure holds,
| then evac with a pump watching the gauges again. Those are some
| pricey one-time use tools. Some mini-splits now have DIY
| connectors and precharged lines to work around those issues.
| Scoundreller wrote:
| When it comes to pricey one-time use tools, I've found that I
| can come ahead by buying online (used or from Asia) and
| reselling it locally once I'm done.
|
| It's the tools I keep that end up costing me. I might need
| that 2nd jack, 3rd ladder, always nice to have a bucket of
| 10mms, bike rack for changing tire 1x/yr.
| wintermutestwin wrote:
| There are some mini-splits that have a "quick connect" type of
| tether that don't require a professional to install. Here is
| one: https://www.forestair.ca/en/serie-mini-anglais
| andrewmunsell wrote:
| I looked at that model (I can't install a traditional mini-
| split at my apartment) as a way of reducing the noise in my
| bedroom b/c of the AC, but the reviews are mostly bad, and
| many related to issues with the refrigerant after trying to
| disconnect and reconnect it over time...
| sokoloff wrote:
| There are units that come with compressors pre-charged with an
| amount of refrigerant for the units and a lineset length of
| between X and Y. You can also buy linesets of different lengths
| that have all the ends pre-fabricated.
|
| After installing everything, you open two valves on the
| compressor unit to flood the lineset and evaporator with the
| refrigerant. It's not perfect [the lines are likely to have
| some water vapor in them], but it works. (The manufacturers
| also charge a premium for these "DIY" versions, so if you can
| find a way to do the traditional charging, you can save some
| money [or apply that towards an HVAC tech to come out, do a
| quick vac the lines/leak test/charge].
| gcds wrote:
| Like are those wall color piping on the left side. The mini
| split ACs in japan come with precharged outdoor unit which has
| valves closed so the installers route lines from indoor to
| outdoor unit (using already packed with insulation lines). The
| connections are made using flare connectors. After all
| connected they use vacuum pump to evacuate air from lines and
| then opened up lines that's basically all in the installation.
| [deleted]
| pwg wrote:
| > Where are the refrigerant lines, how did they run them from
| compressor to evaporator?
|
| Look at this image from the blog post showing the post install
| view:
|
| https://www.techprowd.com/content/images/2020/09/image-24.pn...
|
| Notice on the left edge there is a large white "pipe" running
| from the evaporator unit down to a hole in the wall (the hole
| was already present and visible in other photos). The
| refrigerant lines are running inside that white cover and
| through that hole to the outside unit.
|
| > I thought the biggest issue with AC self install is filling
| the refrigerant and sealing those lines.
|
| As for the refrigerant fill, yes, that is the part of the work
| that most DIY folks will not have the equipment to perform. The
| evaporator and compressor units for most of these mini-split
| units come prefilled with refrigerant plus enough extra for X
| length of tubing (I forget the length X at this time). The
| install basically involves installing the lines, evacuating
| them (refrigeration grade vacuum pump needed here) and then
| opening the shutoff valves in the two units to release the
| already present refrigerant.
|
| Since most DIY's will not have a refrigeration grade vacuum
| pump, and are unlikely to be able to justify the several
| hundred dollars for one for a one-off install, this is the
| point where the DIY'er would need to call a professional for
| the final completion of the install.
| gcds wrote:
| In japan there is also way to rent tools, next time I am
| doing it by myself it costed almost third AC to get 2
| installed... When materials and rent didn't even cost more
| than 1 install cost
| Scoundreller wrote:
| > refrigeration grade vacuum pump needed here
|
| My understanding is that some of the DIY units had a built-in
| vacuum pump for this step.
|
| Edit: never mind, I think I'm making stuff up in my head. But
| I could see it being a feature in the future.
|
| What makes a vacuum unit "refrigeration grade"? Other than
| recovering what you're vacuuming if you're doing maintenance
| instead of a first install?
| pwg wrote:
| Generally what makes it 'refrigeration grade' is the level
| of vacuum down to which it can pull.
|
| Here are some examples of refrigeration vacuum pumps:
|
| https://www.grainger.com/search/hvac-and-
| refrigeration/air-c...
| jcrawfordor wrote:
| Rated to pull high vacuum, <500 micron at the most. You can
| get such pumps very cheaply, the issue is usually the
| volume on them - when I tried using a very cheap ($60) one
| it took a very long time and kept going into thermal
| protect on the way down, and that was with a small system.
| Refrigeration techs use vacuum pumps that both move a large
| volume and can do very high vacuum and that's pretty
| expensive, although not insanely so - I see one from a
| popular HVAC brand for $500.
| bri3d wrote:
| Some mini-splits (MrCool DIY series) also come with the lines
| precharged using quick-connects. These require no
| professional tools or equipment, with the drawback that
| installation is limited to the exact length of line provided.
| johnbrodie wrote:
| I recently installed a mini-split in my garage, Mr. Cool DIY
| 24k. The lines come precharged, as long as you don't need to
| alter the length, you can completely DIY it. Most people just
| coil up the extra line behind the unit if needed, the length of
| my run meant I had no extra.
|
| It's clearly not the same quality as the non-DIY Mitsubishi and
| other units, but US installers barely know what mini-splits are
| anyway. Installing mine cost under 2k total IIRC, and the
| nearest quote from a pro was 5k+. Highly recommended.
| mc32 wrote:
| What I'd like to know is how they safely pipe gas to all
| apartments given the occurrence of earthquakes. Does the main
| valve auto shut off in the event of tremors above M3 of
| something?
| gcds wrote:
| There is heavy measures regarding that topic. One is Gas Meter
| turns off all the gas when earthquake happens. Second I think
| all pipes are flexible so it wouldn't break from earthquakes
| bemmu wrote:
| I also live in Japan, and recently bought 3 new air conditioners,
| but my instinct was the opposite: forego anything "smart".
|
| For tech like that I want it to be as dumb as possible so that
| there are less things that can go wrong with it. As a bonus the
| dumb ones are much cheaper as well.
| gcds wrote:
| Those 2 AC's there almost the cheapest models you can buy for 6
| tatami size and iirc they were 39k/ea. I needed to buy those
| modules extra to make it "smart"
| bemmu wrote:
| Nice, your now smartened ones are actually cheaper than our
| dumb ones then. I was looking at CS-220DFR, also for 6
| tatami, for which the best price on Kakaku is 49k (tax
| inclusive).
|
| But in the end we got three Daikin ones from our moving
| company, because their prices were similar (actually almost
| felt like we get the moving service as a bonus), and it seems
| very convenient to have one company do everything.
|
| Curious to see if they try to sneak in some extra fees at the
| last moment, because as it is I wonder if they're actually
| making a profit with us.
| gcds wrote:
| Exacatly my 30k install cost for 2 ACs were high already
| after all works they like so it will be 15k extra I am like
| WHUT but oh well it's japan next time going to rent tools
| for 5k and materials for like 10k max.
|
| My unit CS-229CFR with tax I think was 42k or similar and
| model to make it smart was +5k so it was still cheaper than
| cheapest smart model
| roel_v wrote:
| Should've bought Daikin A/C's - their network bridges speak HTTP
| with a simple REST service. Highly recommend, it was very easy to
| integrate them into my home automation setup.
| gcds wrote:
| I have already one Panasonic AC, so mixing them didn't feel
| right. Plus I have few extra Echonet Lite devices in home so it
| would be easier for my case.
| roel_v wrote:
| Yeah then it makes sense
| Nextgrid wrote:
| A lot of consumer-grade ACs use IR-based remotes which can
| easily be connected into whatever automation solution you have
| with something like a Broadlink bridge.
| gcds wrote:
| Yes, but only downside of that is beep sounds and stateless,
| while Echonet Lite can provide you all internal properties
| like outdoor temp and etc and also current settings.
| roel_v wrote:
| You can't query those for the current room temp, current
| settings etc. So then if you mix the OEM app & your home
| automation app, things get messed up. IR bridges are a hack
| in home automation, when buying new stuff avoid them.
| squeaky-clean wrote:
| Just my personal opinion, but the thermometer on an A/C
| unit is kind of worthless unless you sit within a foot of
| the unit. I prefer being able to read a sensor on the
| opposite side of the room, or even several sensors
| throughout the house, rather than one on the A/C unit. I
| don't use any OEM app at all, just my own. The OEM ones
| never do exactly what I want, so I have to hack something
| additional onto their features anyways. Home automation
| systems are really personal anyways though. I'm sure anyone
| here who's implemented their own has their own unique
| opinions about what's best ;)
| roel_v wrote:
| Of course, and not only that, but very strongly held
| opinions too :)
| miahi wrote:
| Yes, it was a nice surprise finding that the protocol is that
| simple.
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