The Physics of Hot Air - with Shaun Fitzgerald
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- เผยแพร่เมื่อ 13 มิ.ย. 2024
- Energy use worldwide continues to soar and buildings are responsible for a large percentage of this use.
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Join new Royal Institution Director Shaun Fitzgerald as he will reveal the surprising physics of hot air, and how using his research led him to revolutionise building ventilation with dramatic reductions in energy usage
Watch the Q&A: • Q&A: The Physics of Ho...
Shaun Fitzgerald is the Director of the Royal Institution and a Royal Academy of Engineering Visiting Professor at the Department of Engineering at Cambridge University. He is also the CEO of Breathing Buildings Ltd, a leading technology company pioneering hybrid ventilation systems. He was appointed a Fellow of the Royal Academy of Engineering in 2014.
This talk and Q&A was filmed in the Ri on 24 May 2018.
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Not enough time to cover heat exchange systems, as that is another lecture. However, the headline is this - if you have external temperatures which are so low that additional heating is needed to maintain the average internal temperature at a satisfactory level then it is generally more efficient to use a heat recovery device for those temperatures. However, with heat gains in modern buildings, you get close to zero degrees C before you reach this point. The issue with climates like the UK is that you don’t spend many hours much below that point each year during the occupied day, so a mixing ventilation strategy is best. If you go to cold continental climates though, the story is different. Hence, that’s where heat recovery systems are generally preferred.
do you intend to go into further detail into those systems and is there a possibility of another lecture?
@@susan45tb There are a number of different heat exchange systems one can devise/use. I do cover this in other lectures although it appeals rather more to a narrower audience! Happy to invite you to some lectures next year in Cambridge UK if this is of interest.
Greatly enjoyed thank you for sharing. I was brought back to a talk i watched about a guy making self sustaining "earth ships" basically homes.
Your acknowledgment that a hybrid system, that should include heating, heat pump, heat exchange, and heat recovery systems where necessary, and engineer without them where possible is truly progressive. I'm so tired of so-called environmentalists who look at this as an all or nothing proposition. A true engineer knows that all is compromise in one form or another. Great explanations by the way. I look forward to your next presentation.
I'm fully convinced that the titles of RI talks are constructed in such a way that makes it almost impossible to explain to my friends what i was doing last night.
Thank you, maybe?
The building I work in (a tall high rise) naturally produces a massive updraft through all the stair wells and the elevator shafts, and fans constantly push air down to counteract this force. When the fans stop working (they are on a separate power system from the building so this is rare), the draft is so strong that the elevators stop working and cannot counteract the force. It's amazing how much current buildings can generate just by their inherent design.
I've never thought that ventilation can be so fascinating. Great lecture!
Thank you for this. The complexity is fascinating. I watched it sitting in my rental house sitting atop a hill in Los Angeles, surrounded by portable fans, air filters... wondering if the landlord might not notice if I added vents to the roof.... I used to teach at the Los Angeles RFK Ambassador school complex where the high school gym is a sealed box, doors on the bottom, two large windows in the upper corner--that do not open. Filled with students it quickly heats up to stifling. Mechanical air conditioning full on. In Shiibata Japan there is the wonderfully designed Niigata High School. Japanese summers are incredibly hot and humid, yet this school with rows of clerestory windows that open and close by some method; I never figured it out. Those windows were opening and closing hourly keeping the entire school cool. These are simple, but obvious solutions. Transom windows in old buildings are almost always painted or nailed shut. Yet it only takes getting one open on a hot day to understand why they existed. In my classrooms in the RFK, I would wedge a horizontal piece of cardboard in the upper part of the open door to get the transom flow.
Awesome lecture & great save on the House of Commons & Lords
Totally different topic than I was expecting. I thought this was about Stirling engines, or something.
Me too. He did mention heat pumps, though. The physics of hot air is: when heated a gas will increase in pressure or expand or both, depending upon constraints. Stop. The lecture seemed wayward to me.
absolutely fascinating lecture
Love the water modelling vs the air modelling.
This is a really great field of study and shows how we still need to do a lot of research in natural ventilation. Also temperature comfort is not everything. If we have 21C and 20% humidity in winter, that is a terrible environment and can cause many respiratory problems!
Also just by fixing our current infrastructure, energy consumption would improve a lot. E.g. in our previous company's spaces the thermostats were not adjustable which is not a bad idea since this prevents the fights between employees. The problem was the regulation which was 100% heating in winter and 100% cooling in summer. The result of this was open windows that fixed the excessive heat/cold problem :/
Fantastic lecture!
You could say that the energy savings are literally through the roof. Among other things.
very nice lecture i like that there is no definite answer still, blows your mind in the Comupter Age
Have you guys looked at thermodiode like layers and complete outer airflow shells yet.
Those H pot stacks on the contact theatre have a lot of inelegant steel cross strutting which looks (IMO) dreadful - it's hard to believe someone designed it to look like that on purpose... maybe they weren't allowed to make them out of a self supporting material for planning reasons.
'It's like a sniffer, once it gets going" lmfao 👏😂
Many building codes require tracking the amount of fresh outside air into the building. This makes the bi-directional flow in a single stack pretty much a non-starter at least here in the USA, as the outside air flow is not measurable and reportable so you cannot "prove" that there was at least xyz cubic feet per minute of fresh outside air delivered to the space.
Other than that, this is a very cool talk and very interesting to see the flow demos.
You need to talk to the earth ship guy, he melted a type writer on the top floor in one of his early models =P
Natural ventilation ... an uprising idea in architecture
amazing!! love it!!! TnxAlot 💥🔥 #heatwave2018
Why no mention of heat exchange ventilation systems. I thought it was the top of technological achievement right now.
So there is still no way to ventilate my apartment naturally when it's outside 35C and I want 20C inside...
Not from what I understand. In passing, the lecturer said something about bringing in cold air during the night.
You could try qanat-style ventilation. Have air coming in cooled by passing it trough deep tunnel.
Of course the "simplest" of topics is an exaggeration.
As he mentioned its a current area of research, but there are many fields that know a lot about thermodynamics. Now that architecture is taking a closer look at this aspect, would benefit greatly to learn from them.
and about the questions.. I have some ideas but this is not the correct platform to discuss and debate them.
100 degrees inside...90 degrees outside...regardless if it vents the 90 degree air in or not..it's still hot as fuck. No one wants to work in a office and sweat.
Pity you weren't around in the mid-eighties, I might not have ruined my career trying to promote an air-to-air heat exchanger which could recover 83% of low grade heat at a cost of 10W per kW per cubic metre, and work perfectly in the summer in the opposite direction to keep heat out of the building. Britain couldn't care less. I was in competition with all those H&V companies, and could go to hell. So I did, thanks. I live in the best natural climate in the world, and can monitor the size of your increasing oceans.
Good lecture, but nobody learns anything. I'm sure you know this.
Underground Miners and Mining Engineers would have a lot of direct experience, but you'd have to ask ?
Ok, the title does not fit anything, I thought it was hot air balloon. Please be specific. Otherwise great lecture.
It looks a bit underexplained.
That reference building needs to fire the maintenance department. That's not a design flaw , it an error between the seat and steering wheel . but nice try on selling new building projects.
Why does he make it sound like its QFT? Its the simplest of topics including its governing mathematical equations.
.. But very surprisingly it seems like this aspect of desing is not part of the normal architectural discipline.. humm
your belief that this is the simplest of topics is due to your lack of understanding. maybe with those equations you know you can solve the problem he posed toward the end of the lecture. don't worry, it's simple.
*In reality it comes down to worker productivity not temperature.* In my company the morning the building is hot. Every hour the employees work above productivity they get two degrees of cooling (one actually but the display is rigged to show two) . Less productivity the heat goes back on. This way the a/c pays for itself. In the winter the opposite, the faster the employees work the more their body heats up. When this happens the display on the thermometer goes up but its also rigged so they think its getting warmer. We use the employees body heat to heat the executive suites which are at the top. In summer the a/c just controls the executive suites but they think its cooling the main part of the building. We believe in giving our employees the freedom to be warm or cool through hard rewarding work! Go Free market capitalism!
British Brexit politics of hot air.
Time to learn about the physics which fills the President of the united states
Haha Good one
You must be talking about Dark Matter and Dark Energy, it's creepy physics with him.
+no no It was a joke, also you are not required to engage with Histewy's comment, you aren't required to even read it either. Her comment is not preventing you from discussing science here. ;)
Thanks for understanding. Also I'm a dude lmao, that picture was taken long ago when I had long hair. I don't now.
I come here for science too. Was just a joke. Apologies if you took offence to it.
For thousands of years, we have been building buildings with no regard to physics. I say it's too late to design according to physics. After all, we would only save thousands of dollars per year on heating and cooling. We are a wasteful species and if we do invent "free" zero point energy sources, we would not have to worry about cutting corners on the cost of climate control at all. Money could be spent on more efficient buildings, but does the planning cost outweigh the working cost? This is very scientific, but means only pennies on the dollar. If we colonize Mars, maybe this information would be relevant, but I doubt we can change to a new form of architecture in any short amount of time. Eventually, we will have such powerful computer models and we can make "smart" buildings, but I doubt soon enough.
CandidDate I would say we have been building building regarding to physics without even realising it
Have you ever heard of the Dunning Kruger effect? en.wikipedia.org/wiki/Dunning-Kruger_effect
Lancer --- We've been building for weather and gravitational reasons, not so much air flow. Otherwise we'd all be living in geodesic domes, which have been known to leak rain, I might add.
Your comment is so poorly thought out & doesn't consider so many important things
do you suggest to stop the efforts in energy savings and put everything into coming up with "free zero point energy sources"? How would that work? This is not age of empires, progress is not linear and guaranteed.