Water as thermal mass for a very small low tunnel/cold frame
plantslayer
13 years ago
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oakhill (zone 9A, Calif.)
13 years agomyfamilysfarm
13 years agoRelated Discussions
Thermal mass...Heat sink???
Comments (18)If you are serious about the forced air heat-exchanger you might be better off getting a 10W pool pump and a car radiator with fan, both activated when the temperatures are suitable (for heating the water or cooling the air I would kick the heat-exchanger in at about 28C, for heating the air at about 15C). A low difference in temperature is very inefficient for any heat-exchanger and the three things to optimise are surface area, surface conductivity and counterflow length (unintuitively for low differences the counterflow length term dominates practical designs so good designs are very long). Air bubbles have good surface conductivity but are hard to make a large surface area and counterflow length is very short. Better is a shower heat and fan combination (called bong-coolers in computer circles), and presumably a car radiator is very good too. It's probably a bit hard for most people as you really want a two set-point differential thermostat, something you'd have to build yourself (though it can probably be done with about 10 components). Alternatively you could use the air-exchanger for heat storing/air cooling, and under bench piping for plant heating. This would simplify the logic at the cost of two separate loops. I'd head in this direction if you are serious about thermal mass. You also want lots of water - gbrendemuehl's calculations are right on the money - we're talking up in the thousands of gallons. But you were all going to collect rainwater anyway, weren't you!...See MoreAnother way to use thermal mass
Comments (5)I got my jugs from a nearby university cafeteria recycling bin. I actually talked to the manager and asked if they would stop crushing them for several weeks and also to ask if they would leave the lids on them and they were willing to do this for me. :) I would think that any cafeteria or restaurant with a deep fat fryer would be a likely place to acquire these containers. I'm quite happy to have this system in place tonight because a large number of my potted dahlias now have tender sprouts above ground and it's forecast to drop to around 28F tonight....See Moretomato seedlings in a low tunnel or other simple outdoor structur
Comments (26)I started tomatoes via wintersowing, in a low tunnel-type structure (an upside down, child-height folding table with 6mil plastic over it...the legs of the table holding the plastic up, and then the rest of the plastic tucked under the table), in windowsills, and under lights. At this point, the ones from the windowsills are bigger, sturdier, and leafiest. Of the ones I've hardened off and moved outdoors, one of the windowsill plants is setting blossoms already. (And it really, really shouldn't be this early, but the temps went from freezing to hot here really quickly.) Not that I think anyone has enough windowsills to start 1000 plants, but figured I'd at least chime in with my experience. The ones from the low tunnel-structure and the wintersown ones are running about the same...on the small side. (I did not pre-sprout the low tunnel ones as you mentioned you might do.) The ones grown under lights are about in the middle....See MoreIs my cold water too cold?
Comments (25)I agree with asolo's comments that guaranteed temperatures are a good thing to have even if the temperature setting iof the cycles is somewhat low. That one the main reason for me to get the Bosch washer. I am aware of the actual temperatures of the cycles and that the warm cycle is just 90 degrees (rather cold), but I can adjust the cycle selection accordingly. The sanitary cycle offers 170 degrees (for three minutes, then 150), the kids cycle reaches 150 F and the hot cycle 120. It would be nice to have a few more options, but I can definitely find an appropriate cycle for all my clothes, bedding and towels. jerrod6, the European FLs sold in Europe (220 V, 5-7 kg capacity) coldest cycle is a 30 degree Celsius wash, except for maybe the delicate cycles. So all those washers should heat the water to approx. 90 F which is still below body temperature so the vast majority of clothes won't get any damage... I am not sure if the smaller European washers offered in the US are exactly the same, I guess you'd have to check the specific manuals or call the manufacturer. To the OP, yes, I do think that tap cold water is too cold to get anything clean. It might work on clothes that are very slightly soiled or smelly, but for dog bedding or dish rags I'd always choose a much higher temperature. In our old TL we used the "hot" cotton cycle and the dish rags would still be smelly. The enzymes of the detergents are not active at temperatures below approx. 90 F and no bacteria or fungi get effectively killed at anything below ~140 F. Rinsing your dish rags in the kitchen sink with hot water will most likely get them cleaner than washing them at tap cold temperatures in a washing machine. One thing you can do to kill the germs in dish rags if you really can't or don't want to do hot washes is to put the wet dish rags in the microwave for a minute. Afterwards you can wash them and they should be fairly clean....See MoreSalmanBah
13 years agokudzu9
13 years agokudzu9
13 years agothinman
13 years agogjcore
13 years ago
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