Next Gen Heat Pump Heats & Cools Using Sound!
Vložit
- čas přidán 15. 05. 2024
- Thermo-Acoustic Heat Pump: Roborock S7 Max V Ultra - Buy 1 get 1 Free between 12/14-12/18 ! bit.ly/3VUJO3V
Heat pumps have changed the world in so many ways. Without them, Ice Cream, cold drinks and Las Vegas wouldn't be possible. And how they work is deeply fascinating, but there is a next generation Heat Pump and it works using sound, a thermoacoustic heat pump. How does it work, and what sorts of benefits do they have? Might your next fridge or air conditioner work on sound waves? Let's dig in today on Two Bit da vinci. Next Gen Heat Pump Heats & Cools Using Sound!
NightHawkInLight 's Video!
• Acoustic Cooling & How...
Heat Pump Video Links
• This Heating Tech Brea...
• I'm Shocked How Much M...
》》》SUPPORT THE SHOW!《《《
In-Depth Content @ www.twobitdavinci.com
Become a Patron! geni.us/TwoBitPatreon
Become a CZcams Member! geni.us/TwoBitMember
One Time Donation: geni.us/PaypalMe
》》》GOING SOLAR?《《《
Save 50% on Solar Panels ⟫ geni.us/SolarSteals
Save 50% on Solar Inverters ⟫ geni.us/Inverters
Drone Quotes for Solar ⟫ geni.us/DroneQuote
》》》TWO BIT DA VINCI《《《
I'm Ricky, This is Two Bit da Vinci, and if you're interested in learning about the future of Technology, Energy & Transportation, subscribe & Join us for the ride!
》》》COMPANY OUTREACH 《《《
Sponsor A Video! sponsors@twobit.media
》》》CONNECT WITH US 《《《
Twitter 》 / twobitdavinci
Facebook 》 / twobitdavinci
Instagram 》 / twobitdavinci
Chapters
00:00 Introduction
01:00 Rise of the Heat Pump
02:03 Drawbacks
03:00 Innovation
04:49 Thermo-Acoustic Heat Pump
08:09 Benefits
09:06 Questions
10:51 Conclusions
what we'll cover
two bit da vinci,heat pump,renewable heat incentive,how heat pumps work,clean heat grant scheme,air source heat pump water heater,therm acoustic heat pump,thermo-acoustic heat pump,thermoacoustic cooling,thermoacoustic refrigeration,thermoacoustic heat pump,thermoacoustic heat engine,saving on heating,saving on cooling,heat pumps,heat pump tech,future of heat pumps,heat pump vs air conditioner,This Heat Pumps Sets Records Using Sound! This Heating Tech Breaks Records Using Sound! - Věda a technologie
Checkout the Roborock S7 Max V Ultra - Buy 1 get 1 Free between 12/14-12/18 ! bit.ly/3VUJO3V
How Many Helium Balloons Are Filled Each Year?
We got one as soon as they were available in the US. Wall-E is an awesome little bot running around our house now. 🤣
If you are losing refrigerant from your residential heat pump, refilling it is not part of the maintenance, you need a leak search and repair. Those systems are supposed to be sealed as well. Don’t get scammed by HVAC companies!
@@josephesparza9900 I second this!
Fix that Fuking Mike Pls. For 6 Months the same trash high pitch Audio. For fuk sake Man ! I have to Pas your video through Audio Filter.
"No maintenance"? Helium is an amazing escape artist.
And we're already (slowly) running out of it.
Also classical heat pumps are sealed and they leak all the time it is just usually very slowly.
Exactly. We use helium for leak checks on hyperbaric chambers due to it being so “slippery”
The main reason for leaks is at valve seals. Diffusion through through a tank with no valve (permanently sealed with metal) would take a long time.
@@timderks5960 - the backorder waitlist was about two years the last I heard.
In the '90's, I was surprised that a brand of German home refrigerators had a sonic compressor: a piezo-electric loudspeaker with a buccine-shaped closed chamber. I had never seen that kind of compressors.
I'm a HVAC technician. I install service and maintain heat pumps and all kinds of HVAC systems. I'm excited to see how far heat pump technology has come.
Hi AJ, odd query: do you know how long say a typical modern 2.5kw split AC has to run to make sure its compressor doesn't go without oil? Eg. 5 minutes at a certain % of power capacity? Or do modern units have a way to only run intermittently without running out of oil for the compressor? Cheers
@@jimmybrad156 The compressor should have oil in it when it starts running. It should not need to run to ensure it doesn't go without oil unless there is oil migration. Oil return is not a common issue with smaller systems. Refrigeration systems and some large units will "pump down" or empty the refrigerant from the evaporator at the end of cycles to make sure oil returns to the compressor. I'm in the US so we rate our systems in btu. If my math is right your talking about a roughly 8500 btu system. Like a window unit or mini split? It's very unlikely you have oil return problems unless you're talking about a freezer or something.
@@RoyArrowood Yeh it's a small split. 8500 BTU is spot on (2.5kw.)
Thermoacoustic heat pumps have been around for decades. it's the technology used to cool natural gas to below -160C before shipping in LNG tankers. I'd always wondered why it had never been scaled down for home use.
Thanks for this! I remember watching a science show in rhe early 80's (probably "Living Tomorrow" ) featuring breakthrough studies for A/C & refrigeration using the same tech.
Note to self, buy a good thermostat...
Absolutely. Well known to Cryogenic engineers.
I guess cost reason and scalability
My mother told me a story about her school teacher not believing her about using sound to perform refrigeration, so she took a newspaper clipping on the subject to school. This would have been in the early 50s.
Living in the center of Texas we need A/C in summer. Over time in our little hamlet as the units that pump air through floor vents go out we have learned to install the units for windows not in windows but in a sealed box inside the house at ceiling level with a nice vent on the outside wall. We wire in a new electrical outlet a ways below it and run the A.C cord through the wall until it comes out by it and can be plugged in. It has a tray with a drain to the outside under it. We put several of these in a house and they look not so different than mini-split units. Each has its own remote and the new ones are very efficient, and easy to get at a good price. This way we can fix our own A/C problems and even replace individuals units without having to wait for expensive A/C guys to show up. And cold air coming in at ceiling level is obviously better. One friend told me their summer electric bill was cut in half with the boxed in units.
They made us get rid of cfcs in the 80s and 90s due to the ozone hole. They were replaced with hfcs or hydrofluorocarbons. Hfcs are not as efficient as cfcs so we use more energy for the same amount of cooling.
Now however there is a big push to get rid of hfcs too. My guess is whatever we are supposed to replace them with will be even less efficient. Such progress.
I do remember one company giving up on this tech. They found that the efficiency was not competitive and improving it would mean exploring an enormous design space
just use AI to design it
There's also the issue of needing helium to get it to work. With the shortages we're already having in helium, I'm not sure that a new technology that really requires it is such a good idea.
I do sort of see the theory behind how this might work, but I don't see this one as being practical soon enough to be useful ever. It looks like the population of the world is about to start declining, which opens up opportunities to clean up the atmosphere and if conventional airconditioners are being driven by clean power, then it wouldn't much matter.
I was wondering, a couple weeks ago, how you could melt ice with sound vibration and now here you are. Thanks CZcams.
Spam bot
As someone in the HVAC industry, I am surprised I hadn't heard anything about this technology before. Great work!
Weirdly, I did hear about this many years ago. I dismissed it as science fiction. Well, maybe it's real :)
You hadn't HEARD about it 😂
*I'll see myself to the door*
It's because it's bullcrap
It’s a Tesla invention/design how do you think he was cooling his towers? There’s a lot of suppression regarding his inventions. His design worked off of resonant frequencies rather than frequency generator.
@@barclaymatheson8240 you do know NightHawkInLight built one on his CZcams channel
Cool!
I don't know if it was mentioned in the video, but the working principle of these heat pumps is that of the stirling cycle. This is just up my alley as I'm slightly obsessed with the beautiful simplicity of the stirling cycle. It should in theory be more efficient than the rankine cycle (that is used in your everyday heat pumps which uses a phase shifting working fluid). The biggest drawback of the stirling cycle has however always been the low power density, which has caused big, impractical and expensive machines. If this is solved in these thermo acoustic heat pumps I'd say it is a breakthrough.
Fun fact: The process is reversable, meaning that if you have a temperature difference, It can create a standing wave from which energy in turn can be harvested by the "speaker".
Have you looked into the very old technology, the sterling engine?
When mechanical energy is supplied, it will move thermal energy.
But it also can use a thermal difference to create mechanical energy 🙂
yeah we had a video on it last year!
@@TwoBitDaVinci Must have been before I stumbled across your channel early this year..... 🙂
Makes sense in theory. 30 years no maintenance sounds crazy though. You know how many blown subwoofers I’ve gone through lol
Yeah I don't think we're going to be blasting this speaker like you probably were.
Every new technology is marketed as low maintenence until they actually use it for a few decades and realize all the work that inevitably needs to be done to keep it functional. Reality is never as simple as our theories.
Looks like I need to assemble an old sub into a pipe bent into a circle and see what happens. Really fascinating stuff, thanks!
I love these posts on emerging technologies Ricky. Keep them coming I say!!!
Man. Sound based heating. Space cooled panels. The more I watch this channel the more thermodynamics seems like a barely explored playground begging for creativity. Thank you!
If the 'pseudo-archaeologists' are correct then this is part of the missing technology we used 10,000 years ago: acoustic levitation, acoustic heating/cooling, ultrasonic medicine, etc. I've done A LOT of research on this, and its plausible.
Is there any information on the theoretical efficiency of these devices? Because that would seem to me to be the primary factor in how to view their potential.
Thank you for this animation. So explanative !
Love your content and the march of technology towards a better earth.
Going to be super expensive at the beginning. Existing hvac is so entrenched going to be hard to compete with them. Do you use it with duct work? Minie split head? I think sound and saltwater would produce the same effect. I used to sweat and put the older phone to my face and the speaker would make my face cold when someone talked.
Finally outdoor concerts are possible in Greenland. The noisier the concert the hotter it gets!!
As a sound designer, I love this concept
I have not heard about it for a while, but a year ago Matt Ferrel did a video about "passive" radiative cooling into space, bypassing the greenhouse gasses. The advantage of this technique is that the radiated heat is no longer on earth and not just moved from a building to the atmosphere. Several companies were working on that. Skycool one of them. That seems more promising, but in the end, we will need all options for reducing energy use and increasing the efficiency of cooling.
lol Matt and I cover similar topics, but my sky cool video came out first. yah it's great tech, but doesn't address heating obviously, so a combination would be awesome!
I just want to say I am really enjoying your channel. I also love how you mention other cool channels in your videos ! I'm discovering a lot of very cool channels thanks to you !
This is such cool tech! Keep it coming Nicky
As an HVAC Tech this sound wave heating and Cooling device will be a game changer, if it ever happens. Thank you Ricky Merry Christmas to you and your family
It's been around for over a century. It's not very efficient..
@@Bryan-Hensley And if it isn't something that can be made to work in the next few years, then there's not much point to it ever being developed.
Heard about these years ago. Good stuff.
You can do this now with regular air compressors. Without the phase change of the refrigerant, you are going to have a hard time scaling this up to even residential capacity.
You might as well just do away with the mechanical portion and go with thermal couples powered by solar panels. They are about as efficient as the acoustic systems.
I believe the James Webb Telescope uses a thermal acoustic heat pump to cool the camera so it can see far into the infrared. I guess it only makes sense to try to commercialize it.
Edit: typos.
yeah there is a thermoacoustic heat pump on james webb!
Thanks for covering this tech. Whole house management of heat.. that sounds like a great concept!
Great video. Thanks. Very interesting technology that has me thinking 1.) what can we do with the excess heat when cooling, and 2.) would adding fins around the center of the tube facilitate a greater temperature differential? Of course I know all of this has already been figured out... I just happen to go to "how can I build one myself" in my head. 🙂
Thanks Ricky - very interesting but you also reminded me of all of the various heat sources in our homes as well, that are typically wasted - stoves (we use induction - which I love - so it is reduced), ovens, fridges, etc. All sources of heat. Need to think about how to harvest their heat output. The sound concept is very interesting - it makes sense for sure and it should lower the cost of heating quite dramatically - but I think that there is a lot of heat that we can harvest in out homes that is just passing us by and that we could use anytime for things like heating water, etc. Anyway, food for thought 🙂 Thanks for sharing and have a great festive season 👍
I fully agree with you. 75 - 80% of all heat generated is wasted. I have been doing low temperature thermal energy storage research for years. So much more research needs to be done in this area.
It depends on where you live as well. Most of the heat from household appliances will end up indoors - so if you live somewhere where it's cold most of the year, the energy wasted isn't that much. But in warmer countries, it may be a big waste - especially if it's so hot that one want to use an AC (then not just the heat from the appliances is wasted - but the AC have to waste even more energy to remove that heat as well). So in those places (and even in many cold countries during summer time), it would indeed be nice if the waste heat from many appliances could be used to heat tap water or something instead.
This is much more common in large scale commercial applications. For example, newer or updated hospitals use a system like you mention. They can pull heat off the top floor to cool it and send that heat to a lower floor to heat it and the excess goes into the hot water all at the same time. The downside from what I have found is no one really offers a system like this for the scale of a home. You could build one yourself, but most people are not going to do that for many reasons. You could also tie all the fridge and freezers together into one rack of multistage compressors like they do sometimes in commercial refrigeration. The biggest problem with a system like this is the complexity for a home, the cost, and the downside of 1 failed component could take down the whole system. In a perfect world or someone willing to spend the money and take the risk, it would work well. From a current cost and availability standpoint, it is dead. Most people want cheap and quick, maybe one day.
Thx for bringing new things to our attention 😊
Always!
Love my mini-split heat pumps! heat in the winter and cool in the summer.
Broooooo that ad transition 👌was smooooooooth 😅
Hey thanks for the shoutout! Great video
I always thought that there was a lot of wasted energy happening each time the neighbor with his big sub-woofers passed by.
Perhaps in the future we could invite him over to re-heat our hot water tank, although I'd have to store the glassware and pass out the ear plugs first!
It wouldn't be particularly practical, but if you lined the wall with piezo generators you could probably harvest some of the sound and generate some power out of it. I doubt enough with the speakers we have available, but probably some.
I actually think about heat pumps all the time LOL
me too!
This design seems ideal for an integrated circuit implementation. Multiple tiny cavities with piezoelectric components to generate the waves. And with smaller cavities the volume to area ratio may be more advantageous to heat transfer, which goes by the surface area.
So you mean for a different way to cool electronic components? Perhaps something built into the actual chips?
@@ipp_tutor Exactly! Reserving areas on chips which would use microscopic piezoelectrics to create cold spots. They could become a standard, drop in design component.
@@alvarofernandez5118 That would be really game changing, IMO. Combine that with self-powered chips with nuclear diamond batteries like Ricky suggested in a previous video and you’re laughing
Seems like it might be hard to fill and get a good seal on a microscopic cavity
In my opinion this could be used to make devices unfixable...
7:56 the pipes on the left side of the diagram are incorrectly configured. The cold ‘tap’ should be to the right, where the exchanger is coldest, and the transfer-to-hot-side tap should be all the way to the left (where you show the cold tap).
This is not, back in the early 2000's and up to around 2013, there was a few groups working on this, there was also press releases. One of them was a team from PennState that designed a thermoacoustic refrigerator to keep Ben & Jerry's ice cream frozen. Some of the press releases showed residential refrigerators. The only reason that is getting noticed again is probably all initial patents have expired.
Really interesting, if it works to be better or on par with normal hest pumps but cheaper to produce or buy then it's a winner, plus not dangerous gases win win
Really cool stuff indeed! If it is more efficient than traditional heatpumps, then why not. But of course, as always, it all comes down to cost.
Thanks again Ricky!
Absolutely!
The answer to the question about the technology is, it’s just a matter of finding out how to make it work commercially and the likelihood is, like all of these technologies it will find a place and be able to be used in specific use cases just like infrared heating panels.
So, someone missed the news regarding Victor Schaubager's heating device which uses 2 corrugated copper discs. It's probably on Rex Research. I've considered making some myself. The Japanese would love this, since power is not easy to come by there.
Without knowing conversion rate potential vs purchasing price and running costs, nobody knows....
Great video 👍🏻 nice job guys
🤓
I actually spend a lot of time thinking about heat pumps :P
me too! haha
This coming weekend for much of the US, a heat pump may be very challenged to keep anything warm. :)
As tot he Robot Floor Cleaner. I would love one, but we have sooo many stairs.. lol
This tech looks great for heating, but how does it go for cooling.
Here In Brisbane Australia, our winters are relatively mild. However summer temps exceed 45°C. So cooling is much more important to me.
Exciting technology... can't wait to see it evolve. SoCalFreddy
very intriguing! such an interesting idea to go on, realy impressive ^^
I saw on Real Engineering, that this is what cools the James Web Telescope! Thanks for the video.
I would really like to see all the appliances share a common heat exchanger. It’s always annoyed me thinking about using energy for my refrigerator when its cold outside!
Your refrigerator already heats your home with electric heat. The heat it takes out of your food gets transferred it to your kitchen, and the inefficiency of your fridge also heats your kitchen even more. However, since it's all electric heat, it was expensive to produce, and doesn't reduce your heating bill much, unless you already have electric heat. It's Summer when this works against you; heating your house when your air conditioner tries to cool it. It's your dryer that could use a good heat exchanger, as it throws away most of its heat through an outside vent. Can't safely vent it into your house if it's gas; all the carbon monoxide. That's where a good safe heat exchanger would save you lots of energy and money, if there even is such a thing.
I totally agree with you. There has to be a smart way to couple all the thermal cycles of our home appliances. This would go through a seriously complex home design but I think the end result would be more efficient than what we have now.
@@ipp_tutor Yes, but it would also require all appliance manufacturers to agree on a standard way to tie all of them together. That's a difficult thing to do, but I agree that it's a great idea. It should save a lot of energy, if implemented properly.
I keep my refrigerator on the porch.
@@MARILYNANDERSON88 similarly, I don’t heat my kitchen!
The only place I do heat is my bedroom, and that is with a wood stove (& all the wood comes from my own property and is gathered and cut by myself).
I do sometimes use a portable, infrared light - based, fan forced heater in the adjoining bathroom for brief periods since it is easier than trying to arrange a fan to efficiently blow the warm air from the bedroom into the bathroom, but this is only when I am taking my shower (maybe 10 minutes on average).
Hi Ricky,
Isn't this technology or principle being used in the James Webb Space Telescope?
be interesting to see if there are any long term exposure side effects from the sound waves.
We're getting closer and closer to a different version of something we forgot ;)
i have had a traditional heat pump at my house, air source, since 1995 and it still works, with occassional maintenence.
the biggest fault is when the outside temperature drops below 32 degrees f, it doesn't produce much heat. the manu-
facturer claims it is efficient down to 0 degrees f, but how much heat is in very cold air? during this cold snap (12/22)
my heatpump has been running almost nonstop and producing very little heat. maybe the acoustic version will be better.
Sounds great)
You say it broke records but never mentioned its coefficient nor the conditions in which it managed to hit it.
Is that a good method in the usual range heat pumps even hit 300% efficiency? Can it go even further, like say in -20 degrees? Too many questions unanswered.
This channel is about sensationalism, if you want real answers to your good questions, go elsewhere, to a proper science channel or something.
i vaguely remember a thermo-acoustic application for cooling some years ago
Hoe is a coefficient of greater than 1 possible, since the only energy seems to be from the speaker. Would love to know.
I love your thought experiments! Thank you for sharing and getting my mechanical designer mind, brain storming.
My pleasure! thank you for being awesome :)
I still think an oak log in winter and an open window in summer are hard to replace. No wiring. No bad gasses. Works everywhere. What do you think?
Not sure I understand the first bit about resonant frequency. Are you saying the gas molecules, in addition to being compressed by the forward movement of the speaker diaphragm are also excited to vibrate at a higher state by resonance? What about the energy needed to increase the rate of vibration? Where is that coming from, is it from the compression? Is this sufficient? Because speaker diaphragms move back and forth. When it moves forward it compresses the air in front of it while creating a low pressure area behind it. When it moves back however, the opposite happens. Now its creating low pressure inside the tube, making the gas inside expand and cool. Net effect should be close to zero apart from mechanical heating up of speaker motor. So what aren't I, seeing?
awesome, hope they succeed
You could attach the hot and cold ends to a Stirling engine and recap some of the energy to run the system and just add back in the loss
Sounds good on paper. The most important thing is the insulation of the building itself. You can be very efficient with a regular AC/heat pump too. With a good old R22 🤣😂
I didn't want to read 400+ comments but didn't see an answer about purchasing these heat pumps atm in US from any vender? Can you buy them now as it's been awhile or any status reports? Ty!
Another awesome video. Have you ever looked at the antique tech of the "icy Ball", by Crosley? well worth the look see. God bless you.
God Bless you Randy! No I haven't I'll check it out now!
Great tech 👍
having not watched the video yet. does this open up the possibility of homebrewed apparati of this nature?
1) Clic canal
2) Mirar lista : 🎧
3) Escuchar
I have read that helium gas would slowly leak out of even sealed metal containers. I would definitely ask about that issue if I were to consider maintenance life span....
Awesome technology sound waves to create heat. Who knew?
Very Interesting!!!😁
Thank you. Nice.
Most welcome!
This is a neat concept. You would think nasa and cern are using this now. It would be fun to design. I wonder if we will ever be able to make helium.
Will these heat pumps need to in ground tubing like a ground source heat pump?
There has been so many of these GROUNDBREAKING discoveries for decades now and we never 99.9% of them. There's like a hundred of these videos put up on CZcams every day.
Very interesting! Ty!
Glad you think so cheers!
@@TwoBitDaVinci These would not be two hard to make. You might be able to use a infrared camera to get a good swag on matching the freq with the tube shape, but I'm guessing a time measurement of the reflecting wave might be a better indicator, but that requires a receiver circuit to measure it and expensive electronics. I've done this with radar but not sound. The tech is totally doable but requires money to develop. I see a lot of potential with the proper funding.
Strange there is no commercially available unit today. How long will we have wait for one that is competitively priced?
If they work well, their inherently lower cost of materials and installation should make them a massive big winner! But how long do we have to wait for the COP to be big enough?
"Paul Atredes learned that his name was a cooling sound." (reference David Lynch's Dune, with the "killing sound" idea.)
This technology is what allows the James Webb Space Telescope to work. They can’t have vibrations from a compressor mess up the images they’re trying to take, so they use this to reduce vibrations. It allows them to get temperatures of a few hundred degrees below 0 which is what’s required to allow the sensor to detect deep infrared wavelengths.
Couldn't really grasp the idea of how this will transfer heat. Sure you explained how acoustic energy turns into thermal energy. But first, we have to take the heat from let's say out of the house and convert it into acoustic energy in order to transfer it back into thermal energy to pump in the house. How is the heat gets transferred from one space to the other?
Maintenance free for decades? Now that's what I want for my car/aircraft/insert mobile heavy duty application.
I'm still a bit confused. Is this thing just concentrating heat energy from inside the tube so that it can be brought outside? In other words. would the inside of the tube just get colder and colder until absolute zero? How would this cool my refrigerator?
even cooler is the idea of having a house that claims to need no cooling or heating like an earthship or wooden houses like "Holz100" houses.
Or an aircrete dome.
Ooo, interesting 😀
So cool
The present medium for the sound is a gas, but wouldn't a liquid be more powerful? If the sound can compress gas and create Heat it should also be able to compress liquid. Create your sound in atmosphere beside your liquid. Is your current sound like a rhythmic Bang?
Sounds like it has some great potential. Reminds me of the peltier cooler.
Interesting, I've heard of acoustic cooling a decade ago. Someone told me a story that one day someone noticed that as metal cools it lets off a sound, so they played the same frequency back at room temperature metal and it cooled it! Wonder if this could assist in making an acoustic heat pump?
In the acoustic chamber, seeing as it is completely sealed would hydrogen not be a good option? it's extremely cheap and abundant.
Apart from the energy efficiencies of the acoustic heat pump tube itself, the losses in the amplifier will have to be considered.
Thx. for the video. That was informative. Could you do a video on 'Clear Hydrogen' please? No, I am NOT talking about Green H2. This is supposed to be Carbon Negative. There in a company in Canada called 'Proton Technologies' who has already filed about 100 patents on this. I thought it would be interesting to know your take on this since you specialize on Eco friendly technologies on this channel.
So is it possible to make more electrical power per input with a heat pump?
Can't wait for these and thermomagnetics to take over my industry
If you have calcified water, and use a clothing dryer, and have this cleaner robot; you should conserve the water from the dryer in order to use this in the robot vacuumer. Presto; less maintenance and water saved.
1. What's their EER? (Btus/watt)
2. Can they cool just as well as heat a space?
3. Name of manufacturers, pricing, etc?
Thank you! 🙏🏽✌🏽🔆
There is such a thing as Google. You can answer those questions yourself.