Heat pumps of the 1800s are becoming the technology of the future • Hacker News Board

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

#471

Post by lsaferite » Tue, Jan 17, 2023, 6:34 PM UTC

mvnuweucxqokii wrote: post #292

tomcam wrote: post #277

Earlier quoted context omitted.

Because it smells bad inside? Because fresh air feels good? Not to be snarky, but how did you miss these use cases?

If it's pretty cold outside, then you're throwing all of the ostensible energy savings of a heat pump out the window the minute you open it to air out the house. Following the thread of conversation, it just didn't compute to me: >>>> Heat pumps are great for climate control >>> Yeah, ducts are dead >> What if you want to recirculate air in your house through your central air filter to eliminate smells? > Just open t…

I'm not sure why "Heat pumps are great for climate control" went to "ducts are dead".

I live in Florida, we've used Heat Pumps for as long as I can remember. We also have central air handlers with blowers and ducts to distribute the conditioned air. Mini-splits can _also_ be ducted mini-splits. According to my HVAC geek friend, mini-splits are pretty terrible about humidity control (an important thing in Florida). For proper humidity control you'd ideally have a dedicated set of dehumidification ducts (powered by a central dehumidifier) as well. Mix in an ERV and you have the ability to build a fairly air-tight house with _controlled_ ventilation and very efficient conditioning of the air in the house.

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

#472

Post by poutine » Tue, Jan 17, 2023, 6:45 PM UTC

nemo44x wrote: post #208

poutine wrote: post #184

Earlier quoted context omitted.

It's expensive and it doesn't cool. Also doesn't circulate the air. I have some fancy filters and humidifiers as part of the system I'm putting in.

It will certainly cost more, especially since you can’t share the venting and blower. But I’d get it quoted to compare. Electric systems have really come down in price per SqFt. Now your climate doesn’t get month after month of freezing temperatures so maybe it won’t be as dramatic but the energy cost savings can be huge. Plus the overall experience of it is the best imo. You could still circulate air with the blower…

I got it quoted. Basically would be around $50k CAN for heated floors (it's a big house). Ducted mini split heat pump (2 units to handle the house size) was $60k. Central hybrid gas-heat pump was $30k.

I put in heated electric floors in the bathrooms (about $1k each).

Byrant has a humidifier (https://www.bryant.com/en/us/products/humidifiers/) that integrates with the system. It also has integral HRV. As well as an air purifier: https://www.bryant.com/en/us/products/air-purifiers/dgapa/

It's not a bad compromise for our climate. Currently living in a home I designed that has mini splits everywhere and I really dont like them. Not enough air circulation and it's really hard to balance given a well insulated house on mildly cool days which is very common here.

I intend to always keep the fan going to circulate the air in order to clean (we have allergies) and humidify.

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

#473

Post by lsaferite » Tue, Jan 17, 2023, 6:47 PM UTC

westurner wrote: post #364

jwcooper wrote: post #148

Earlier quoted context omitted.

Where I live, it can get very cold. Not always very efficient to open windows for 5 months out of the year. A great option for keeping CO2 levels down in a house is with an HRV (or ERV) [1] that will heat the fresh air coming in to cycle it throughout the house. [1] https://en.wikipedia.org/wiki/Heat_recovery_ventilation

From the ERV/HRV (Energy Recovery Ventilation / Heat Recovery Ventilation) wikipedia page: https://en.wikipedia.org/wiki/Energy_recovery_ventilation#Ty... : > During the warmer seasons, an ERV system pre-cools and dehumidifies; During cooler seasons the system humidifies and pre-heats.[1] An ERV system helps HVAC design meet ventilation and energy standards (e.g., ASHRAE), improves indoor air quality and reduces tota…

IME you don't use an ERV alone. You'd use it _with_ a Heat Pump. The ERV is all about transferring heat from one airstream to another. It's _not_ a device that manages indoor temperatures though, just recovers some of the latent energy in the air. In the process it's also managing humidity mainly as a by-product. The humidification properties of the ERV allow you to run the Heat Pump in a more efficient manner. I have an HVAC geek friend who explained the whole process, but essentially (in non physics/fluid dynamics[?] terminology), if the Heat Pump doesn't need to dehumidify air it can operate more efficiently.

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

#474

Post by darken » Tue, Jan 17, 2023, 7:28 PM UTC

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…

I'll try recording something next time I clean one of the units (one needs a deep clean this spring); no promises though. In the meantime, here are some quick notes/resources.

This video shows a similar process using water pressure to clean the unit: https://www.youtube.com/watch?v=xcIVAv8YbPQ

Some more tips and modifications:

- I cover the electronics in a garage bag held with tape. No need to unscrew the black cover over the power wires to disassemble (I unnecessarily removed this a few times heh).

- I ended up really liking this cleaning shrowd after trying a few; the hard pieces on the sides are key for making it easy to secure nicely, which many others lack: https://www.amazon.com/gp/aw/d/B083S85X97

- I spend more time (like 30min+) spraying the blower wheel so it spins. I alternate spraying with fresh water with spraying diluted "Lemocide" (@10% dilution) from a spray bottle a bunch of times depending how dirty it is. I use this https://snowjoe.com/products/sun-joe-wa24c-lte-24v-150-psi-m...> which at 100 PSI is 10x stronger than a hand pump sprayer, but 10x weaker than a real pressure washer. I.e. the sweet spot IMO.

- I use foaming coil clean from a can to clean the fins if they're particularly dirty. (WARNING: I have not used in the same cleaning as the Lemocide since I haven't confirmed if they're compatible, so be careful of any reactions if you use both in the same cleaning.)

- I take the outer casings outside for a quick rinse with the hose and dish soap if they're really dusty.

- I tape cheap plastic mirrors at 45 degree angle above the unit so I can see it from above and carefully vacuum the back coil (there are 3 folded over in a U, and you can only see 2 from the front). Otherwise this just accumulates junk and is hard to see. This also really helps with finding the 3x clips at the top of the case that secure it to the back housing.

I may have a few more notes worth sharing at some point; feel free to ping me if you have any specific questions.

Edit: See also this quick video on unclogging the drain line on a Daikin (though I used the sprayer against the tube instead of my mouth...): https://m.youtube.com/watch?v=GDrHe-rli98

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

#475

Post by mrexroad » Tue, Jan 17, 2023, 7:33 PM UTC

phyzome wrote: post #144

> owners of drafty homes may need to take on the added cost of insulation when installing a heat pump Installing good insulation is also really important even if you're not using heat pumps! With bad insulation, you're wasting energy no matter what technology you're using.

Don’t forget air sealing while at it!

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

#476

Post by ClumsyPilot » Tue, Jan 17, 2023, 7:40 PM UTC

kwhitefoot wrote: post #466

ClumsyPilot wrote: post #414

Earlier quoted context omitted.

> But yes, the GP is full of shit. Or you live insulated from shitty alliances and low income life. A friend's husband was killed by a faulty boiler, carbon monoxide poisoning. In 2015 I lived in a house where boiler ignition didn't work and you had to reach inside with a lighter. That unit was definately not sealed. UK only required consenser boilers since 2005, the ones before that used to air from inside your hous…

Condenser boilers and balanced flue are separate concepts. The house I bought in 1978 had balanced flue gas heaters but they were not condensing. Condensing boilers are an efficiency measure. Balanced flue boilers have been available in the UK since the mid sixties.

All I can do is share personal experience of living in rental properties in UK, and if these boilers were really sealed, my acquaintance wouldn't be dead.

Whether most boilers are prehistoric, or it's just years of neglect, I don't know.

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

#477

Post by nemo44x » Tue, Jan 17, 2023, 7:59 PM UTC

2rsf wrote: post #445

nemo44x wrote: post #441

Earlier quoted context omitted.

They’re much more efficient (and comfortable imo) than other systems. You’ll see pretty big costs savings. But yes, you need to be in a climate that sees long, cold winters to get the best of them I guess. Or if your home has lots of tile/stone/concrete flooring. You’re right though, they take awhile to heat up and if you’re in a place where you may need heat at night and AC in the day, they won’t be ideal.

Pretty big costs savings compared to what? if you compare radiators to floor heating, both connected to the same heat pump system than the savings are not significant

It's because of efficiency. The entire floor becomes a radiant source - this is a massive thermal source. A heat-pump is only part of the equation. You need to deliver the heat still. A radiator is generally a bad way to deliver heat from a heat pump. Radiated floors are much better. About 40% more efficient than radiators from the same heat pump.

Not to mention radiators are sort of lousy ways to heat a room anyways. They take up space and leave one side too hot and the other too cold.

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

#478

Post by bumby » Tue, Jan 17, 2023, 8:01 PM UTC

tempestn wrote: post #403

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.

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 a…

It’s worth noting that ASHRAE ventilation standards are based on “bioeffluence” levels which may or may not correlate well to other IAQ values like CO2, VOCs, etc.

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

#479

Post by nemo44x » Tue, Jan 17, 2023, 8:02 PM UTC

poutine wrote: post #472

nemo44x wrote: post #208

Earlier quoted context omitted.

It will certainly cost more, especially since you can’t share the venting and blower. But I’d get it quoted to compare. Electric systems have really come down in price per SqFt. Now your climate doesn’t get month after month of freezing temperatures so maybe it won’t be as dramatic but the energy cost savings can be huge. Plus the overall experience of it is the best imo. You could still circulate air with the blower…

I got it quoted. Basically would be around $50k CAN for heated floors (it's a big house). Ducted mini split heat pump (2 units to handle the house size) was $60k. Central hybrid gas-heat pump was $30k. I put in heated electric floors in the bathrooms (about $1k each). Byrant has a humidifier ( https://www.bryant.com/en/us/products/humidifiers/ ) that integrates with the system. It also has integral HRV. As well as an…

> I put in heated electric floors in the bathrooms (about $1k each).

Smart man.

> Currently living in a home I designed that has mini splits everywhere and I really dont like them.

I have a similar opinion. They're fine in a 1-off room that is isolated but I don't like them much otherwise. They don't look good at all.

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

#480

Post by thedougd » Tue, Jan 17, 2023, 8:47 PM UTC

mrexroad wrote: post #464

thedougd wrote: post #437

Earlier quoted context omitted.

I believe they now sell other size lines and extensions. I got hung up on the excess line set idea and did a full DIY install of a non-DIY model mini-split. I bought, borrowed, and rented a lot of tools, spent a lot of time researching and learning. I really wish I went with the DIY model. Despite that lesson, I may do it again when I finish my attic space, but this time I'll add copper line brazing to the list.

Was there anything beyond the extra time/effort that made you regret going with a non-DIY model? I’m considering doing the non-DIY in next year or so.

No, not at all. I enjoyed it but my wife had a different expectation of completion date than I. My advice is to get the tools, don't shortcut, so that you have confidence at each step.

Stuff I had already specific to HVAC:

-R-410a manifold, gauges, and hoses.

Stuff I went out and bought:

-Nitrogen tank pressure regulator and hose for HVAC.

-Mandrel pipe bender

-Flaring tool

-Micron vacuum gauge

-A slightly better copper pipe cutter and deburring tool.

Stuff I rented/borrowed:

-Vacuum pump from Autozone. Free. It was plenty big enough for a minisplit.

-Full nitrogen cylinder rental from Airgas.

Things I'm glad I did:

-Used a wall mount instead of a pad for the compressor unit. Unit stays clean.

- Pressure testing with nitrogen. It's worth the money and effort to know up front it doesn't leak.

-Followed a more thorough procedure for vacuuming/drying which involves vacuuming down several times and flushing with nitrogen. I got a much better vacuum after subsequent flushes.