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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

#341

Post by EricE »

briHass wrote: post #218
fifteenforty wrote: post #154

Earlier quoted context omitted.

US and Australian units are different for insulation, but in my terms the insulation around the best ducts is R1.5, but good ceiling insulation is R6. 4x difference Edit: not to mention the huge difference in surface area. Ducts can expose your conditioned air to a huge, poorly insulated surface. Bad for efficiency.

Interesting. The code for duct insulation in unconditioned spaces in the US is R8, and they're pushing for higher currently. They also recently undid a long held myth about ducts buried in insulation leading to condensation issues. Most areas now allow ducts to be buried as long as you have R19 above and below, or R30 above. When I just installed a ducted mini for 3 upstairs bedrooms, I surrounded my R8 flex duct wit…

lol - it's not a myth. It's physics: https://www.youtube.com/watch?v=Vufih-WN5R4

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

#342

Post by timbit42 »

acdha wrote: post #322
timbit42 wrote: post #313

Earlier quoted context omitted.

It's not that black or white. I only need a backup for my heat pumps for perhaps a week each winter. The heat pump still saves me 40% on my heating costs throughout the year. Also, Norway doesn't get as cold as you might think. They get some heat from the gulf stream in the Atlantic ocean like the UK does. Russia and Canada get a lot colder in their northern parts, like -40C quite often and sometimes even as low as -…

I’ve been wondering where the break-even points will be for ground source systems, too. I was talking with an architect a couple weeks ago who has looked into that for several projects and didn’t find the number close to working out, but that was in Boston where the winter climate is nowhere near that extreme and the labor/land costs are very high and space issues meant they’d have to do the most expensive vertical b…

10 years ago the average heat pump had a CoP of 3. Today they are 4 or a bit higher. Some ground source heat pumps have a CoP over 5. I saw one unit with 5.3. Of course, with a ground source heat pump, you can actually get that CoP when the outside air is -50C.

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

#343

Post by EricE »

gautamdivgi wrote: post #225
jimmaswell wrote: post #151

Earlier quoted context omitted.

> Ducts are dead. How do you move the heated/cooled air into/around the house without ducts?

How would it behave in a place like Chicago where we've had recent weather events that take the temperature from 40F to -10F in a couple of days? Will the system catch up that fast without ducts?

Faster since you just target the rooms you occupy.

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

#344

Post by telcal »

Brybry wrote: post #314
darken wrote: post #266

Earlier quoted context omitted.

I love our Daikin mini-splits (came with the house), but as you allude to I've had to become an mini expert on deep cleaning them. They've can get GROSS with mold when used for cooling, and the cursory filter only does so much. That being said, now they stay clean for a few years after a deep cleaning -- though my first few attempt before I refined the process did not stay clean nearly as long. (Proper water pressure…

I'd love to see a youtube video of your cleaning methodology. Most of the videos from HVAC people are... sketchy to the say the least. I've seen videos where they dismantle the whole indoor unit and leave the coil just hanging from the line set or zip tied to the backplate while they take the fan and drain pan outside to clean. One easy thing we've found that helps with drain clogs is to use a shop vacuum from outsid…

This is a video for the Mr. Cool brand of mini splits. Starting about the 45s mark you'll see how they do it without removing the unit. https://iwae.com/resources/videos/mrcool-care-kit-ductless-m...

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

#345

Post by warble »

EricE wrote: post #335
fifteenforty wrote: post #269

Earlier quoted context omitted.

The no 1 reason I bought the Daikin model referenced over the comparable Mitsubishi Electric is that it has the ‘MOULD PROOF’ function. It runs the fan automatically after you have had it in cooling mode, to evaporate the moisture build up from the interior condenser coil, thereby removing the moisture required for the growth of bacteria and mould. So far, it seems to be working! Better than relying on everyone to ma…

If you live in any kind of area with high humidity you just shifted the mold from the AC unit to the rest of your house. Hell even here in the desert I'm not sure I'd want to use that "feature".

I live in the desert. Any humidity we can get in the summer is good.

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

#346

Post by throwawayacc3 »

operatingthetan wrote: post #176
fifteenforty wrote: post #167

Earlier quoted context omitted.

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.

Good callout. Some people have the strangest reasons to hate high-efficiency ductless systems.

Except it's incorrect. The best system is a "ducted ductless" system that circulates and filters air throughout the house.

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

#347

Post by [deleted] »

teruakohatu wrote: post #111
phkahler wrote: post #35

Earlier quoted context omitted.

The fridge is heating your home, so that reduces the burden on whatever is heating your home. The coil on the back gets hot.

> The fridge is heating your home Not really, efficienty aside the heat it puts out the back is coming from inside the fridge... Which is coming from the room housing the fridge. So over the course of a day it should be neutral.

[deleted]

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

#348

Post by elil17 »

ezzaf wrote: post #187
elil17 wrote: post #79

Earlier quoted context omitted.

If you have a resistance electric furnace, that is essentially true. With gas, you add the electric generation and distribution losses, which is a pretty big difference. It does cost more to run an appliance than to heat with gas.

If you account for the electric generation and distribution losses, you should do the same for gas. "It does cost more to run an appliance than to heat with gas." That's highly dependent on the appliances involved and the price you pay for each fuel. For me, a heat pump is much cheaper to run. You really need to calculate it for each individual situation.

Heat pumps and electric furnaces are not the same thing

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

#349

Post by lll-o-lll »

danuker wrote: post #319
lll-o-lll wrote: post #282

Earlier quoted context omitted.

Not physically. Bad for our souls.

My soul abhors waste and enjoys comfort. I would feel terrible either knowing I'm wasting half my heating energy, or freezing in my home.

Warm climate, remember? If you cannot cope with an ambient temperature that drops below 20C, there is this thing called “radiant heat”. You can make it with fire.

Also, relatively small amounts of electricity. Radiant, just like your soul would become.

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

#350

Post by elil17 »

sidewndr46 wrote: post #327
elil17 wrote: post #79

Earlier quoted context omitted.

If you have a resistance electric furnace, that is essentially true. With gas, you add the electric generation and distribution losses, which is a pretty big difference. It does cost more to run an appliance than to heat with gas.

But if we're going with the "heatpumps are more than 100% efficient" that everyone brings out, then running my computer to work & heat my room is far above 200% efficiency. If I'm running my computer to use it & it keeps me warm, there is no way turning on a natural gas heater is going to reduce my costs.

Heatpumps are more than 100% efficient refers to a technical specification measure called efficiency, which is watts of heating per watt of energy input. For space heaters, electric furnaces, and your computer (/many other appliances), it’s always 100%. For modern gas furnaces it can be 90%ish (but the difference in electricity and gas prices mean that gas furnaces are still cheaper). For heat pumps it’s typically between 200% and 540%.

If you have a thermostat in your home, any appliances you use will reduce your heating usage because the thermostat will automatically decrease how much the furnace runs. So, yeah, it’s not wasteful to vent your computer exhaust outside in the winter, but no one’s doing that. On the other hand, it’s not worth it to run appliances you wouldn’t otherwise run unless you have an electric furnace, in which case it doesn’t matter.

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