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Heat pumps of the 1800s are becoming the technology of the future

knowablemagazine.org

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Re: Heat pumps of the 1800s are becoming the technology of the future

#401

Post by NavinF »

biofunsf wrote: post #371
kccqzy wrote: post #132

Earlier quoted context omitted.

Not being snarky but why don't you just open the window for that? I have a CO2 detector that I believe is a reasonable proxy for stale air. When it goes above 1000 I simply open the windows. By the time I remember to close the windows the reading is almost always below 500.

digression: Any recommendations for a good CO2 detector?

AutoPilot APCEM2

The only requirement is "2 channel low drift NDIR gas sensor". Cheap CO2 detectors either have zero IR sensors (instead they guesstimate eCO2 using a VOC sensor) or a single IR sensor that requires weekly calibration outdoors or it will just assume that the lowest sensor reading means 400ppm.

Re: Heat pumps of the 1800s are becoming the technology of the future

#402

Post by tempestn »

fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

Ducts are good for indoor air quality though. Keeping our central fan on at low speed all the time significantly reduces measured CO2 in occupied rooms, particularly bedrooms overnight.

Re: Heat pumps of the 1800s are becoming the technology of the future

#403

Post by tempestn »

fifteenforty wrote: post #167
throw0101a wrote: post #118

Earlier quoted context omitted.

> Ducts are dead. Ducts are still needed to circulate air, especially if you want to remove stale air (e.g., bathrooms, kitchen) and bring in (filtered) fresh air (to bedrooms).

A recirculating central heating system doesn't do that. As mentioned below you either need exhaust only ventilation, balanced ventilation or ideally ERV/HRV. All of the above are available in both ducted and ductless forms.

A recirculation system will prevent high levels of CO2 buildup in occupied rooms, particularly with closed doors. I've measured the difference in our bedroom overnight between having the fan on and off, and it was dramatic (if I recall correctly, something like 700ppm in the morning vs 2000). Even if it's only keeping the level consistent throughout the house, that would be a benefit. But every house will have some amount of air leakage as well; a recirculation fan with a fresh air intake (which all modern ones have) will pull in fresh, filtered and conditioned air to replace air that leaks out. If that's not sufficient for indoor air quality, then you can crack a window or set an exhaust fan to run periodically. I haven't generally found that necessary though.

ERV/HRV has its place it less moderate climates where there is significant efficiency loss from pulling in outdoor air, especially if indoor conditions require a significant amount of fresh air turnover. But a central HVAC system with a recirculation fan most definitely can be beneficial in a lot of cases.

Re: Heat pumps of the 1800s are becoming the technology of the future

#404

Post by lll-o-lll »

abigail95 wrote: post #397
lll-o-lll wrote: post #192

Earlier quoted context omitted.

If you live in a warm climate, I personally think insulation is the worst (excepting roofing). Not because of efficiency, but because you isolate yourself from nature! The traditional Queenslander (look up Bluey if you don’t know what I mean), has so much going for it. It allows airflow through the whole house, a protected outside to sit and be with nature, lizards coming and going, bliss! This hermetically sealed en…

Australians have a very strange relationship to insulation and temperature. Some might say it's the defining feature and purpose of having shelter is that we don't live at the mercy of the weather. I can't run a business with indoor temps from 24-31c during business hours. Compounding loss of brain function outside of 18-23c is found by every study I've read. The less exposure to particulate pollution and extreme tem…

Don’t generalise from me. I am a very strange Australian!

From a business perspective, I think you are probably right. I don’t personally find cold affects my brain function (you can put on warm clothing right?), but heat probably does once we get above 30c. It’s summer right now in Aus, might be affecting some of my posting.

For home though, I’m happy for the inside to be much the same as the outside. Mostly though, I just want the interface between my home and the natural world to be permeable. I think that’s good for mental health, and that the pros outweigh the cons. The thing is that you can’t have that and properly insulate it at the same time. So a choice has to be made, and I personally lean towards less insulation/more lizards.

Having said that, we’re all different, whatever floats your boat. If you prefer plastic bubbles inside caves of steel, who am I to judge?

Re: Heat pumps of the 1800s are becoming the technology of the future

#405

Post by hnbad »

It's astonishing to me to see an article present heat pumps as innovative new tech and insulation as something worth looking into.

In Germany if you want to build a house, almost every construction company will default to some variant of heat pumps. Actual plumbing companies are more likely to recommend an air-sourced heat pump, prefab construction companies seem to have taken a liking to air-air heat pumps (which like air conditioners pump hot air into rooms rather than running hot water pipes through the building for heating) but either way it'll be a heat pump of some kind or another.

Also not only is there a legal minimum requirement for insulation but all grants and subsidies (when available) specify a minimum standard for insulation that must be met. Note that in new constructions they're also combined with a ventilation system to prevent mould and improve air quality. In older buildings retrofitted with modern insulation, tenants are usually instructed on how to vent by opening the windows.

On the other hand, air conditioning is almost unheard of compared to the US outside retail. Even office buildings usually only have desk fans.

Re: Heat pumps of the 1800s are becoming the technology of the future

#406

Post by [deleted] »

Brybry wrote: post #199
fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

I don't think the hardware is that expensive in the US, it's the installation (which costs more than the hardware). And mistakes by installers will cost even more. Our installers didn't flare a line set connection properly and it leaked slowly and that was a very expensive bill (especially since refrigerants have changed so much). Our Daikin indoor units have also had condensate leaking issues, probably due to poor i…

[deleted]

Re: Heat pumps of the 1800s are becoming the technology of the future

#407

Post by [deleted] »

fifteenforty wrote: post #109

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units includ…

[deleted]

Re: Heat pumps of the 1800s are becoming the technology of the future

#409

Post by duckmysick »

jonplackett wrote: post #312

> Lord Kelvin proposed using heat pump systems for space heating way back in 1852. The first heat pump was designed and built a few years later That’s the kind of speed we need if this is going to be any help before everything’s on fire anyway. From what I can tell (in / for the UK at least) heat pumps currently aren’t that great - my dad’s boiler just died and every plumber he spoke to said heat pumps kinda suck and…

> every plumber he spoke to said heat pumps kinda suck

What did they say precisely?

Re: Heat pumps of the 1800s are becoming the technology of the future

#410

Post by creativenolo »

jonplackett wrote: post #382
Danieru wrote: post #354

Earlier quoted context omitted.

"I talked to a bunch of horse tamers and they say cars are just no good. So I bought another horse. I don't see all the hype" Similar issue in the states. HVAC specialist trash talking mini splits because a mini split's advantage of cheaper maintenance and install is meaningless to the HVAC specialist. Instead they only see the trade offs. Then they quote a bill as if installing a mini split requires a diploma and po…

This isn’t an appropriate analogy - the plumbers also fit the heat pumps. They just don’t recommend them

Horse tamers drive cars. I think the analogy is more about what you're set up to do, used to and profit from.
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