July 07, 2022, 04:01:58 AM
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Topic: De-ice Bridges  (Read 138 times)

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Offline Enthalpy

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De-ice Bridges
« on: May 22, 2022, 05:19:46 PM »
Hello everybody!

Zeolites produce heat when adsorbing water reversibly, which may heat homes in Winter from Summer sunlight, and I learned recently that after a century, this process progresses.
Energy density (around 330kJ/kg without casing nor auxiliaries) nears that of lithium batteries for cheaper.

Could they find other uses?

Forget hand heaters, self-heating food cans and self-warming dildos for walkers: single-use reactions like quicklime hydration and iron oxidation bring around 5MJ/kg.

Heating a Moon or Mars station isn't limited by material cost. Mass decides. The cycle lasts only 14+14 terrestrial days on the Moon and 1 day or 2 years on Mars depending on the latitude. A battery is lighter than zeolites but the solar panels to recharge it are heavy. It's much a matter of durability and of competing storage materials.

Hot water bottles? Water from +70°C to +30°C stores only 167kJ/kg, molten paraffin around 250kJ/kg at constant temperature. But I'd like the zeolite process to keep all high-tech and electricity out of the bed, possibly as separate components.

Could heat from zeolites warm bridges to avoid icing? Warming is (or was) done in Switzerland and must cost a shiny penny. Bridges offer area for sunlight collectors, most locations in Switzerland enjoy sunny summers. I didn't put figures.

CaCl2 dried or dehydrated by sunlight can de-ice bridges too. CaCl2 melts snow and ice by dissolution, and by its big heat of dissolution too if dehydrated. It would be sprinkled on the bridge when needed, rather by fixed means. The sewer all around the bridge would direct the brine to a tank for reuse, but direct the rainwater of normal times to its usual destination. During sunny time, in summer if needed, heat dries the brine back to CaCl2, preferibly dehydrated by exceeding +150°C.

My gut feeling: the CaCl2 process must use far less energy than heating the bridge, it's simpler and faster. Side screens shall collect the splashing brine.

Marc Schaefer, aka Enthalpy

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