Circulating fan uses tenth the energy of an air conditioner.
The Revenge of the Circulating Fan https://www.lowtechmagazine.com/2014/09/circulating-fans-air...
“Cold Tube” cooling system uses half the energy of an air conditioner
131–137 of 137 posts
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#132> The notoriously bad energy efficiency of air conditioners Air conditioners are actually pretty fantastically efficient for what they do. The problem with air conditioners is that there's no way to move a ton of heat without using a lot of energy. So, they do use a lot, but they make the most of it. What's truly bad are our buildings that have the minimal insulation and sealing possible, leaking all that cold air ri…
New buildings are rather efficient in US. The problem is old buildings that use 5X the energy for HVAC. I echo that AC is quite efficient. Far more efficient than traditional heating. There's a misconception that hot areas are less environmentally friendly due to AC. The opposite is true. Hot areas are only 25 freedom units hotter than humans prefer. Cold areas have months of 50+ temperature difference. The misconcep…
> New buildings are rather efficient in US.
They can be, and there's lots of modern construction techniques that are really good (search term "building science").
One big problem is that a lot of stuff is still built to "minimum code" which just isn't that great. On top of that, sloppy construction work can significantly undermine what is done. In my own house I've fixed several simple things, like missing insulation around vents and holes cut too big (or created by a hammer, rather than cutting).
Here's a good walkthrough of a house under construction showing lots of problems typical to any subdivision (non-custom) build: https://youtu.be/OmU2N_Q732A
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#133Earlier quoted context omitted.
Is NG really over 5X cheaper than electricity? It seems like a NG genset that is better than 20% efficient wouldn't be that hard to build, yet I don't see people running their houses off of electricity that way.
In the US, natural gas averages $11.85 per 1,000 cubic feet. Electric averages $0.13 / kwh. 1,000 cubic feet of natural gas is a bit over 1 million BTU. That converts to 297 kwh of electricity. that 1,015,000 btu costs: $38.61 in electric $11.85 in natural gas
So 3-4x rather than 5-10x
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#134Earlier quoted context omitted.
> [^1] in fact, if you put it in the shade then it would warm up because it could no longer radiate to space. If I understand correctly, this isn't quite right. If it's in the shade, then whatever is shading it is radiating more heat onto it (because the shading object is hotter than space) and possibly reflecting its own radiated heat back. If it's under a clear sky then it's receiving less heat, so what it loses by…
I agree with your description, OP possibly concised his words a little too much as to imply the wrong thing.
I agree too :)
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#135Earlier quoted context omitted.
Nice. Seems related to: https://en.wikipedia.org/wiki/Planetary_equilibrium_temperat... The temperature of a perfect black body in earth’s orbit would be ~255K (-18C) (This is not the case for the technology under discussion because it’s very much not a black body) I will point out that even at modest (astronomically speaking) distances, the solid angle of a star gets preeeeetty small. For example, a black body at ju…
> The temperature of a perfect black body in earth’s orbit would be ~255K (-18C) More precisely, of a perfect black body in Earth's orbit with the same surface area and shape as Earth.
Yes, only true for black spheres. It’s size invariant though.
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#136Earlier quoted context omitted.
Best marketing voice : "Why migrate to the sunbelt? Burn gas and wait for climate change to bring the warmth to you!" ...sigh. I really hope it doesn't go this way.
Any time I buy property I check how far above sea level it is, so I can estimate when I'll be able to sell it as beachfront property...
I absolutely agree regarding climate change nuances for long term property investing!
Two things confound me:
- good internet now for my relaxation gaming vs right location for climate change.
- predicting what council rates (US has Land tax I think?!?) might turn into when the town realises it will be half underwater...
Re: “Cold Tube” cooling system uses half the energy of an air conditioner
#137Earlier quoted context omitted.
I was recently shopping for an AC unit and had to get a portable one because I have bars over my windows. Having seen the Technology Connections video I naturally tried to get a dual-hose model, but after seeing the specs (and the prices) I ended up getting a single-hose model anyway. If we go by the DOE SACC ratings, this single-hose toshiba [0] has a 14% higher SACC rating than this dual hose whynter [1], for the s…
The problem with an efficiency rating that includes air ingress is that the outdoor air temperature is an unconstrained variable. The dual hose unit will likely outperform significantly if the temperature delta is high, but if the temp delta is low then the single-hose unit is probably better as it likely has a more efficient compressor. It looks like DOE SACC tests assume the outdoor air temp is 83 degrees for 80% o…
I think you nailed it. The DOE SACC/CEER rating system provides more realistic numbers for comparing portables to window units, but the assumption of a small temperature differential gives single-hose units and unfair advantage over dual-hose units. A single-hose AC is like running your car AC on fresh air mode, it cools faster if the inside of the car is hotter than outside, but it can only drop the interior temperature so far below ambient.
In case anyone is interested, I did not end up returning my single-hose unit, but I did end up buying a dual-hose Whynter ARC-122DHP [0] for another room. It came with a yellow energy guide card listing a cooling capacity of 12000 BTUs and an EER of 11.1, which indicates an average power draw of just 1081 watts (EER=BTU/watt). Unfortunately no SACC or CEER rating was listed. Actually measuring power shows that it draws the full 1200 watts on startup, quickly drops to around 1100 watts, and then slowly drops to 900 watts as the room temperature falls. For comparison, my 8000 BTU (unknown EER, 6000 SACC, 6.5 CEER) single-hose Toshiba RAC-PD0812CRRU [1] also draws 1200 watts on startup, quickly drops to around 900 watts, and then slowly drops to 800 watts as the room temperature falls. So it seems like the dual-hose is around 20-30% more efficient (in a different room under arbitrary conditions) based off the BTU rating, but no better based off the SACC rating. I also noticed that it did not come with foam seals for the window bar like the single-hose unit did, so there is probably room for some efficiency gain there.
[0] https://www.whynter.com/product/whynter-elite-12000-btu-dual...
[1] https://www.toshiba-lifestyle.com/us/Room-Air-Conditioners/P...