Home Office Projects Series: Air conditioner setup • Hacker News Board

Re: Home Office Projects Series: Air conditioner setup

#91

Post by sgc » Thu, Sep 03, 2020, 5:51 PM UTC

Melkman wrote: post #56

amluto wrote: post #43

Earlier quoted context omitted.

> 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-f…

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 b…

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.

Re: Home Office Projects Series: Air conditioner setup

#92

Post by bkovacev » Thu, Sep 03, 2020, 5:58 PM UTC

Scoundreller wrote: post #31

rsync wrote: post #24

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 wher…

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. A…

Why would it fail within 5 years? Isn't the usual lifespan of those pumps 10-15 years?

Re: Home Office Projects Series: Air conditioner setup

#93

Post by Spivak » Thu, Sep 03, 2020, 5:59 PM UTC

tantalor wrote: post #64

Spivak wrote: post #40

Earlier quoted context omitted.

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 eq…

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.

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.

Re: Home Office Projects Series: Air conditioner setup

#94

Post by criddell » Thu, Sep 03, 2020, 6:06 PM UTC

bluGill wrote: post #87

criddell wrote: post #80

Earlier quoted context omitted.

The examples seem to mostly be looking at cooling and dehumidifying. What do radian floors for heating have to do with that?

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)

> 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.

Re: Home Office Projects Series: Air conditioner setup

#95

Post by spockz » Thu, Sep 03, 2020, 6:07 PM UTC

ClumsyPilot wrote: post #72

rsync wrote: post #24

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 wher…

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…

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.

Re: Home Office Projects Series: Air conditioner setup

#96

Post by sergeykish » Thu, Sep 03, 2020, 6:11 PM UTC

ClumsyPilot wrote: post #72

rsync wrote: post #24

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 wher…

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…

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, 25°C 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-...

Re: Home Office Projects Series: Air conditioner setup

#97

Post by m0zg » Thu, Sep 03, 2020, 6:12 PM UTC

ClumsyPilot wrote: post #72

rsync wrote: post #24

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 wher…

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…

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.

Re: Home Office Projects Series: Air conditioner setup

#98

Post by oehtXRwMkIs » Thu, Sep 03, 2020, 6:14 PM UTC

L_Rahman wrote: post #63

rsync wrote: post #24

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 wher…

This examples fails to account for the fact that radiant floor heating is a default feature in all new Korean homes.

You mean mainly apartment units right?

Re: Home Office Projects Series: Air conditioner setup

#99

Post by larrywright » Thu, Sep 03, 2020, 6:24 PM UTC

jonpurdy wrote: post #89

rsync wrote: post #24

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 wher…

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…

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.

Re: Home Office Projects Series: Air conditioner setup

#100

Post by larrywright » Thu, Sep 03, 2020, 6:29 PM UTC

criddell wrote: post #94

bluGill wrote: post #87

Earlier quoted context omitted.

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)

> 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.

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.