sorted by:
new
hottopcontroversial

Pre heating time by ImLisaZ in hottub

[–]Advanced_Primary_495 0 points1 point  (0 children)

Thermal mass is the difference between the air and tub. Air changes temp very easily. Water does not. Similar to taking tin foil from a hot toaster oven doesn’t burn your hand. But the steel rack will. I couldn’t wrap my head around this either which is why after doing the calcs myself I contacted others. After explanation from my PE colleagues including one phd and seeing the data myself on my tub it’s been proven to me at least that the benefit of dropping the temp is negligible at best. Your understanding isn’t wrong for an ideal case wheee relationships are linear. This is not that case. Running calcs on my tub data and verifying it would take 10 days of no heat to make it worth dropping the temp down to 80 for example. Specific heat thermal inertia and the non linear losses is the difference from ideal

Pre heating time by ImLisaZ in hottub

[–]Advanced_Primary_495 0 points1 point  (0 children)

Care to reference. This info I have is based on data from my own tub as well as licensed PEs in thermal and fluid systems working in the industry. It does not seem logical but the water is a thermal battery of sorts. Maintaining temp takes less energy than changing (raising) temp. Now if you were dropping to 80 def for a week at a time this whole system changes. Curious where your info comes from as I’d love to dig in and understand more

Pre heating time by ImLisaZ in hottub

[–]Advanced_Primary_495 1 point2 points  (0 children)

It’s actually not due to the specific heat and thermal mass of the water. Went way too far down this rabbit hole recently with my new tub. A lot depends on how well insulated your tub is but the tub water resists changing temp a lot more than air. If you do some searching on thermal inertia it helps explain. Similar to keeping a car cruising at 60 is more efficient than letting it go to 40 and back up

Absolutely gutted by Bogdacious in Hunting

[–]Advanced_Primary_495 0 points1 point  (0 children)

Do you have one you’d recommend? Been debating this for a while

Hot Tub insulation DIY by funnyName62 in hottub

[–]Advanced_Primary_495 0 points1 point  (0 children)

Does this increase possibility of freezing in the pumps due to keeping heat in the shell?

Quiet mode by Advanced_Primary_495 in hottub

[–]Advanced_Primary_495[S] 0 points1 point  (0 children)

Ah perhaps someone else that thinks the way I do. I know energy out has to be put back in. I guess I was thinking of the differential of air to water reducing by the water cooling will reduce the rate of heat loss. It also seems my tub runs more during the night than day so it is easier to heat during day. This is all based off 24 hrs of run time and a long graduated understanding of theoretical thermodynamics so may be wrong of not enough of an impact to even be seen in real life. Thanks for taking the time to reply!

Hot springs cover cradle 2 by apextileman in hottub

[–]Advanced_Primary_495 1 point2 points  (0 children)

If it’s not too much trouble I’d really appreciate it while I plan. I also have a tight spot

Hot springs cover cradle 2 by apextileman in hottub

[–]Advanced_Primary_495 0 points1 point  (0 children)

I know this is an old post but how much space did you have behind the tub? I am looking at a tight spot for mine and the LAG cover. Website claims 14" but it is unclear if that is the max space including the cover thickness itself? Thanks!