HN Theater @HNTheaterMonth

Obligatory very interesting video regarding heat pumps from Technology Connections: https://www.youtube.com/watch?v=7J52mDjZzto

They are great if you are looking to use electricity to heat because they are 3 to 4 times more efficient than resistive heaters. It depends on the price of electricity and other heat sources in your area.

If you live in the north where temperatures go below -15 Celsius, air-to-air units aren't as great because they lose efficiency as it gets colder outside. My heat pump has a COP of 3, meaning it can generate as much heat as a resistive heater using 1/3 the electricity, but it shuts off at -15 Celsius because below that point it is less efficient than resistive heat. If your heat pump has a COP of 4, you might get to -25 Celsius before it is less efficient than a resistive heater.

Better, but more costly, heat pumps use in-ground water, either from a pair of wells, or from a deep pond that won't freeze to the bottom, or from many meters of water pipe buried deep enough beneath your lawn to not freeze in the winter. Because of the depth, they always have access to the earth's heat so they don't lose efficiency in the winter.

The Technology Connections YT channel has a couple of good videos about how them:

1. https://www.youtube.com/watch?v=7J52mDjZzto

2. https://www.youtube.com/watch?v=7zrx-b2sLUs

The argument is that for regions that do not spend much time below 15 degrees Fahrenheit, they tend to be cheaper to run because they can pump more heat than electricity they use, effectively becoming 300% efficient instead of 95% efficient for say an gas heater.

As the temperature differential between the desired temperature and the outside temperature increases however, the efficiency does drop and what you say is true, but for most of the populated world, this is not the situation.

https://www.youtube.com/watch?v=7J52mDjZzto

(edit: I think you're going to get a lot of links to the overly in depth series tech connections, but I'm leaving it here all the same)

It feels obligatory to reference Technology Connection in a thread about heat pumps. TC is a super fun YouTube channel that digs j to everyday technology and has had a number of episodes on heat pumps and modern thermodynamic management challenges and technologies.

https://youtu.be/7J52mDjZzto

⬐ bcjordan

Came here to post this :D

The TC channel is definitely a hacker's eye view in to all the technologies that we take for granted every day. Tons of fascinating tech history covered, too.

Other fun ones:

- a defense of the simple drip coffee maker https://youtu.be/Sp9H0MO-qS8

- why do the turn signals not sync up when you're at a stop light? https://youtu.be/2z5A-COlDPk

- how humidifiers work and ehy the simple swamp cooler style are pretty ideal https://youtu.be/oHeehYYgl28

- why dishwasher detergent packs are stupid (use powder/liquid) and why you should use the pre-wash slot and not bother pre rinsing your plates https://youtu.be/_rBO8neWw04

- why do light switches click? https://youtu.be/jrMiqEkSk48

⬐ oezi

> - why dishwasher detergent packs are stupid (use powder/liquid)

? I thought that powder and liquid for dishwashers have come out worse on any consumer reports test (at least here in Germany).

⬐ WastingMyTime89

Most dishwashers are designed to do a pre-wash, change the water, then do a wash. Pre-wash requires detergent to work optimally, ideally one specifically designed for pre-washing. Even dishwashers which have no pre-wash detergent dispenser will typically tell you to add some detergent directly on the door in the instruction manual. Most packs are suboptimal for that. Technically they should be used in addition to pre-wash detergent but that kind of defeats the point of using a pack.

⬐ Scoundreller

Best advice I learned from that channel was to run the sink faucet until it’s hot. Then run the dishwasher so it starts its cycle with actually hot water.

⬐ blacksmith_tb

Hmm, dishwashers I have had (including my current one) have a large heating element in the bottom, I would have thought that could heat the relatively small volume of water in there pretty quickly?

⬐ zo1

Most (actually all) dishwashers that I've encountered are designed to not get hot water coming in. Where I live a high-pressure hot-water outlet is not the norm at all. And yet, we don't have a catastrophic country-wide problem with dirty dishes. I'd argue that something else it at play.

⬐ Scoundreller

Not on this continent. But obviously the advice can be ignored if your dishwasher isn't connected to hot water.

The reason for your setup is probably 240V electricity that is affordable enough to resort to resistive heating.

⬐ oezi

A good dishwasher (based on testing) will never need some manual tinkering like this.

⬐ oezi

Packs should be put in the dispenser so they don't act during prewash.

⬐ mschild

Detergent packs in the US seem to be mostly gel packs. In Germany, most tabs are simply hard pressed powder. Gel packs did fail in their cleaning function and the recommendation generally goes for either tabs or powder, where powder can save you money because you set the dosage according to how full your dishwasher is.

⬐ lupire

Fine tuning powder per wash sounds like overoptimization. Just useing powder instead of tabs will save most of the money.

⬐ Scoundreller

But I save time by pouring in less when less is needed.

⬐ oezi

Prepackaged tabs with self-disolving packaging is actually the cheapest if you assign a non-zero amount of money to your own time.

⬐ kortex

How much extra time does it take to dump out some powder? I don't actually measure precisely and just eyeball it. The advantage is I can dump some extra in the bay to act as pre-wash. The cost is 4-10x more for the self-dissolving packs.

⬐ sokoloff

I looked on Amazon at Cascade powder ($0.22/oz in large packages) and the same name tablets ($0.30/tablet in large packages).

A load with powder is typically 0.75 oz. ($0.165/load) or about 55% the cost, not 10-25% the cost.

Being able to dump in extra for pre-wash is an advantage to powder for sure.

⬐ pottertheotter

I take his stuff with a grain of salt because I found the dishwasher detergent recommendation to be a bad idea.

A while before the TC video came out, I had an appliance repair person working on my fridge and asked him what he thought the best detergent was and he said use powdered, not the packs. So we switched to that.

Not long after our dishes were never getting cleaned. I thought it was a problem with the dishwasher so I took apart the filter, cleaned all the sprayers, etc. but nothing worked. Was thinking we needed a new dishwasher until one day we ran out of powdered detergent but had a couple packs left over so my wife used one.

Bingo! Our dishes came out PERFECT. We haven’t had a single problem since.

⬐ lupire

When you used powder, did you add detergent to the prewash cycle?

TC did make an apology video after the first detergent video.

⬐ pottertheotter

I usually put some in the prewash area.

⬐ cromka

Quite the contrary for me. I suppose your powder detergent might be of lower quality than the packs one, or is not as concentrated and you need to use more of it?

⬐ pottertheotter

I used Cascade Complete powder and Cascade Platinum packs.

⬐ desmosxxx

Did you get the powder from Amazon perhaps? I'm pretty sure we got fake detergent on Amazon before and it caused our dishes to not clean properly.

Also if you have a water softener you should typically use less powder.

We definitely get a better wash using the right amount of powder, but had to adjust the levels ourselves.

Powder should be better, but dishwashers can be weird, so whatever works best.

⬐ cromka

I, too, had to adjust the amount of powder. Roughly 1/2 of recommended dose goes onto tray, and an additional 1/5 directly into the washer for prewash cycle.

⬐ BoiledCabbage

Did you change brands or types when you switched to powder?

⬐ pottertheotter

I used Cascade Platinum packs before and after trying powder. When using powder I primarily used Cascade Complete (there was a short time early in the pandemic when I had to grab whatever was available on the shelf).

⬐ smhg

I tried the 'add detergent to the pre-wash-cycle' part. While it seems to make sense, it also caused a lot more rust spots on cutlery. The detergent is just too aggressive that way.

⬐ alliao

the goal is to use the cheapest not the most expensive... my miele tablets were destroying my duralex picardie big time, so I now use the cheapest powder and if I feel like the stainless steel don't shine bright enough (maybe once a month) then I use one miele tablet...

⬐ _xerces_

The packs are just powder pressed into a cube with some colorful liquid added to a little pocket to make it look high tech.

⬐ kortex

What kind of powder are you using? Some really cheap powders are basically just sodium carbonate and silicate, with some enzymes, and no actual detergents. These won't work well if your load is "too clean", as it needs some grease to saponify in order to generate detergent.

The medium/high quality stuff contains more/better detergents, water conditioners, and sometimes rinse aids. The packs are just powder formulations pressed into a pellet.

⬐ pottertheotter

I mostly used Cascade Complete powder (there was a point early in the pandemic when I had to grab whatever was on the shelf) and use Cascade Platinum packs.

A couple months back we ran out of packs and had some powder leftover, so I ran a load with the powder. I ended up having to run the load again once we got the packs.

That video: https://youtu.be/7J52mDjZzto

I feel like it's almost a requirement to take this opportunity to share Technology Connections great video [1] on the topic.

Personally, I've used a heat pump as the sole heating unit for my house for the past 6 years or so. There have been a few cases where I've opted to use an extra blanket, but overall the results have been pretty impressive, and the cost savings are pretty huge. (Apartment, so no fuel heat, it's electric or nothing)

[1] https://youtu.be/7J52mDjZzto

⬐ bklaasen

Don't you find the background rumble of the air in the vents very enervating? I was in a friend's place with a heat pump, and I felt like I was inside a badly tuned organ. Lots of atonal near-subsonic rumbling. I think heat pump vendors need to learn about acoustics: standing waves, reverberation, phase interference.

⬐ positr0n

Is a heat pump any different from regular air conditioning in that regard?

I'm from an area of the country where you run the AC 8 months out of the year so this question is weird to me unless somehow a heat pump (reverse AC) is different than an AC pump running normally.

⬐ CincinnatiMan

My two heat pumps aren’t too bad. The airflow is the same as the AC, meaning sound is present but no rumbling.

⬐ thedougd

There are hydronic heat pump systems available as well.

⬐ kencausey

That is not likely to having anything to do with being a heat pump. That is probably just the consequences of the blower, the length of ducts, how they are mounted, etc.

Technology connections did a great video on heat pumps.

https://youtu.be/7J52mDjZzto

One of the best things is that is an air conditioner you run in reverse to get some heating.

Thankfully, you are wrong about that! Just like you don't need a cooler source _from which to source cold_ in the summer with AC. Technology Connections has a fun (well, to me) video on how heat pumps work and are great. Literally just AC units running in reverse, thanks to having a valve.

https://www.youtube.com/watch?v=7J52mDjZzto

⬐ extra88

Yes, Technology Connections is a great channel and added a couple of new videos about heat pumps in the past month.

https://www.youtube.com/c/TechnologyConnections/videos

It depends on the heat pump. If you get a mini-split, and have decent insulation, they can work down to -20C:

* https://www.mitsubishielectric.ca/en/hvac/professionals/fs-s...

* https://www.mitsubishicomfort.com/articles/what-is-a-heat-pu...

* https://www.fujitsu-general.com/us/residential/benefits/year...

Some folks using them in Alaska:

* https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...

If you get a heat pump that looks like the 'traditional' external AC unit (giant cube), those tend to work down to about +5C. Not sure how much more they cost above a 'regular' air conditioner:

* https://www.lennox.com/products/heating-cooling/heat-pumps

The Technology Connections channel has a couple of interesting videos on the topic of heat pumps:

* https://www.youtube.com/watch?v=7J52mDjZzto

* https://www.youtube.com/watch?v=7zrx-b2sLUs

He has a video entitled "How to calculate when heat pumps make financial sense (and other heat pump follow-up thoughts)":

* https://www.youtube.com/watch?v=BRdq2ExLJns

NR Canada has a "AIR-SOURCE HEAT PUMP SIZING AND SELECTION GUIDE":

* https://www.nrcan.gc.ca/sites/nrcan/files/canmetenergy/pdf/A...

Financially speaking you're going to have to break out a spreadsheet and plug numbers in: (natural) gas prices, electricity prices, efficiency of the units, etc. Doing a search for "heat pump calculator" may get you started.

⬐ hedora

Page 10 has numbers for current market leaders:

https://www.nrel.gov/docs/fy11osti/52175.pdf

I walk through the "what's the break even temperature" elsewhere in this thread (where I pasted the same URL).

Also, it is kind of a moot point. If you're putting in central air (not a minisplit), it will probably automatically fall back to natural gas or resistive if it gets too cold outside. (Too cold should be something like -5F or less, assuming it falls back to resistive.)

There are highly efficient heat pump powered water heaters, going out anywhere remote, these and other heat pump systems should really be used. This is a really great overview https://www.youtube.com/watch?v=7J52mDjZzto&t=1840s

⬐ exhilaration

I knew that was a Technology Connections video before clicking on it :)

Our house is electrically heated via a heat pump, which has appreciably more efficiency than a resistance heater (or computer).

Here's a neat video about them: https://www.youtube.com/watch?v=7J52mDjZzto

⬐ lkbm

Yeah, a heat pump is definitely better if you have it. My point is that if you don't, mining provides the same energy-to-heat conversion ratio.

My house is from the 1800s and only has heating for the kitchen/dining room/living room.

His whole channel (called Technology Connections) is probably my favorite one on YouTube, can’t recommend it enough! My favorites are his series on refrigeration and heat pumps, for example this one:

https://youtube.com/watch?v=7J52mDjZzto

Edit: to clarify, this article is based on an old Technology Connections video, and the creator of that video has lots more!

⬐ netizen-936824

Seconded, I learned a ton about A/V systems from him. He has excellent technical content. Learning about how the old electromechanical juke boxes worked was fascinating.

I can also recommend Applied Science. He explains the concepts behind numerous concepts and applies them to a home project in his garage. Such project include: Home made electron microscope Chemical glass strengthening Robotic cookie maker Creating X-Rays Messing around with supercritical CO2

https://m.youtube.com/c/AppliedScience/videos

He does all sorts of random shit and it is absolutely wonderful

⬐ progre

His videos is an amazing demonstration of a general scientific engineering process: "At the 84:th attempt I started to see some promising results..."

⬐ myself248

For A/V stuff, I went looking for an understanding of how color works in video systems, and ran across this gem from Captain Disillusion:

https://www.youtube.com/watch?v=FTKP0Y9MVus

His whole channel is great, though there's not a ton there, it makes sense given the staggering amount of work that goes into the visualizations of each one.

⬐ Groxx

Applied Science is amazing, +1 highly recommended. Well, to both.

⬐ barbazoo

Love his channel! My favourite videos are the ones about dishwashers.

⬐ garaetjjte

CED saga for me.

⬐ ASalazarMX

He won me with the video about why hurricane lamps look like they do: https://www.youtube.com/watch?v=tURHTuKHBZs

⬐ a012

I watched a few videos from his channel and always amazed/wondered how can he has so many vintage items and deep knowledge of/around them. I really enjoy his presentation skill and sense of humour.

⬐ beervirus

The jokes are painfully corny. But everything else about his channel is gold.

⬐ kelnos

I'm a pretty corny person, so I enjoy them. Not laugh-out-loud funny, but at least smile-worthy.

I do really enjoy his presentation style, and the technical content is well-written and fascinating.

⬐ DiabloD3

Technology Connections is hands down one of my favorite Youtube channels.

Another guy worth mentioning that tickles the brain cells in a similar way is Isaac Arthur: a guy that breaks down science fiction into science fact, and explores what we could actually do someday in the future, and pokes fun at the stuff that will probably never happen but has become familiar tropes anyways.

https://www.youtube.com/channel/UCZFipeZtQM5CKUjx6grh54g

If you want another down to earth (ahem) channel that also explores tech, there's Tech Ingredients who has done crazy things like build the ultimate (and certainly weirdest) speakers, his own epoxy, his own thermal paste, his own whiskey with his own still, his own compressorless fridge and AC, his own rocket motors....

https://www.youtube.com/user/TechIngredients

⬐ zem

Isaac Arthur is almost certainly a pseudonym paying homage to Isaac Asimov and Arthur C Clarke

⬐ freemint

Would be but is surprisingly not.

⬐ zem

wow, okay, that's surprising for sure!

⬐ AussieWog93

Nominative determinism strikes again!

⬐ anamexis

Thanks, I wasn't aware of those two!

Riffing on those, I can also recommend DIY Perks. He makes pretty stunning electronics projects. https://www.youtube.com/c/DIYPerks

⬐ Laforet

I might just come forward and recommend NighthawkInLight. He does not upload as frequently as some of the other channels mentioned here but his videos tend to have a much higher production value for some just as interesting topics of science and technology.

https://youtube.com/c/Nighthawkinlight

> I'm wondering if there's any low-energy or green solutions to this.

The answer is "it depends". How your flat is designed will have an impact on what you can do. But if you are able and willing to do some house work, there is a lot you can have control over.

At the end of the day, it's all about how you can control humidity, the flow of hot and cold air and humidity. At your disposal, tools such as conductive materials, insulating materials, etc. Google "passive house" to see the concept and what these things use.

With that said. Heat pumps are incredibly efficient, and replacing your heater with a reversible air conditioner which you can then run in both summer and winter will do far more for your overall energy efficiency than anything else you can do.

Most of your energy consumption comes from winter-time heating. Start here for a good introduction to heat pumps and how they are so efficient: https://www.youtube.com/watch?v=7J52mDjZzto

https://archive.is/NrQQC for those who don't want to support Salon with clicks.

The article just wanders aimlessly between lies.

Pumped Hydro dams are tiny compared to hydro-power or water dams and are beautiful, the same size as solar or wheat farms. A cool seawater based one in Japan - https://www.google.com/search?q=okinawa+pumped+storage+&tbm=...

A good example of a government doing something that worked is the Australian government which wanted to spend money fighting the global financial crisis so insulated homes. Unfortunately deaths from the scheme, which were at the same rate as normal but became larger in number stop people talking about it much.

This tale of heat pump water heaters stopping a dam is rubbish. Where is the mathematics?

Heat pumps are awesome however, go to Technology Connections, not this to learn about them - https://www.youtube.com/watch?v=7J52mDjZzto

⬐ splitstud

It's almost as if simple schemes can't solve systemic problems

⬐ sidewndr46

The one you reference is a very poor example of pumped hydro. It's nameplate capacity was only 30 MW, it was uneconomical to operate, and was dismantled in 2016.

This video is a great explainer on heat pumps [1]. The TL;DR is that they are essentially nothing more than air conditioners that run in the opposite direction. Plus, a heat pump and an air conditioner can be combined into a single system.

1: https://youtu.be/7J52mDjZzto

⬐ sgerenser

Not just can be combined they effectively always are. I’m not aware of any residential heat pumps sold in the US at least that don’t also operate in cooling mode. The additional cost is basically just a reversing valve.

Yes, there's a ROI period. It's a matter of pay now or pay later (over time).

Obligatory Technology Connections video:

* https://www.youtube.com/watch?v=7J52mDjZzto

Watch this: https://www.youtube.com/watch?v=7J52mDjZzto

> So the heat pumps can also do cooling during the summer?

Here's a pair of really great videos about heat pumps and what they can (and could, in the future) do:

https://www.youtube.com/watch?v=7J52mDjZzto

https://www.youtube.com/watch?v=7zrx-b2sLUs

> no wasted power

Electric heating can be much more efficient than what's effectively resistive heating with 500%+ efficiencies being possible.

Search for "heat pumps" or watch: https://www.youtube.com/watch?v=7J52mDjZzto

⬐ arcticbull

Someone else mentioned heat pumps to me in this context too, I'm unfortunately really limited in what I can use in my apartment. It's a condo complex made of brick put up in 1906 - without heating or air conditioning. I'm not in a position to install external hardware. My parents have a heat pump set-up in their house though!

Watched the video by the way, thanks!

Related Technology Connections video: https://www.youtube.com/watch?v=7J52mDjZzto

⬐ dzhiurgis

These need to integrate HRV to be ultimate killer in home heating.

Technology Connections posted this just an hour ago.

https://youtu.be/7J52mDjZzto