DIY solar dehumidifier - Page 6

jeff5may · 05-24-14, 05:40 PM

A new thread recently popped up, introducing a new concept for indirect evaporative cooling and dehumidification of buildings:

http://ecorenovator.org/forum/geothe...25-energy.html

The NREL paper describing the system, named the DEVAP, is here:
http://search.nrel.gov/cs.html?url=h...nrel&n=4&la=en

This thread got me thinking about the solar dehumidifier again. Indoors, a desiccant waterfall or forced air, swamp cooler type unit would dehumidify the air. Outdoors, a solar desalination tower could effectively remove as much water as one needed. Consider this description borrowed from Wikipedia:

In 1993 a desalination plant was invented by Akhtar Iqbal Zuberi in Pakistan. Zuberi’s plant produces 40 liters of water per square meter per day. This is at least ten (10) times more productive than a conventional Horizontal Solar desalination plant. Water desalinated from this plant has 16 parts per million (ppm).[14]

The structure is a raised tower made of cement, with a tank at the top. The whole plant is covered with glass of the same shape, but slightly larger, allowing for a gap between the cement tower and the glass.

The tank is filled with saline water and water from an outside tank, drop by drop water enters the inner tank. The excessive water from the inner tank drips out onto the cement walls of the tower, from top to bottom. By solar radiation, the water on the wet surface and in the tank evaporate and condense on the inner surface of the glass cylinder and flow down onto the collecting drain channel. Meanwhile, the concentrated saline water drains out through a saline drain.

In this process fresh saline water is continuously added to the walls from the top of the tower. After evaporation, the remaining saline water falls down and drains out continuously. The movement of water also increases the energy of molecules and increases the evaporation process. The increase in the tower’s height also increases the production.

This plant’s base is 3.5 by 1.5 feet by 10 foot high, and gives about 12 liters of water per day.Built horizontally, a structured plant receives solar radiation at noon only. But Zuberi’s plant is a vertical tower and receives solar energy from sunrise till sunset. From early morning, it receives perpendicular radiation on one side of the plant. While at noon its top, gets radiation equivalent to the horizontal plant. From noon till sunset, the other side receives maximum radiation. By increasing the height, the tower plant receives more solar energy and the inner temperature increases as height increases. Ultimately this increases the water yield.

A number of experiments have been conducted and a much more productive plant has been developed, with further work continuing.

This project can be implemented anywhere there is ground water, brine or sea water available with suitable sun. During different experiments a plant six (6) 6 feet high can attain a temperature of 60 degrees Celsius, while a plant of ten (10) feet high can reach a temperature of up to 86 degree Celsius.

http://www.energyglobe.info/awards/n...8#.U4FRUnJdV48

In this application, there is no need to save the purified water. Once the evaporation process has occurred, we are done. Therefore, a simple thermostat-controlled venting system could be used to "smokestack" the humid air from the top of the tower. This humid air would be replaced by ambient air at the bottom of the tower. With the original application, the shaded side of the plant would definitely condense more water.

This assumes a tower made of concrete or bricks, but the tower may not need to be constructed as such. For example, a dark colored strip of towels or other wicking material sandwiched between suntuf panels may work well. The structure would need additional support, which may end up costing more than cinder blocks. As long as it got sun on both sides, it would collect the same energy from the sun.

jeff5may · 05-24-14, 10:19 PM

For a test run or proof of concept, one could build a "water honcho".

Water Honcho Portable Solar Powered Desalination and Water filter systems. Portable solar desalination, drinking water filter. FRESH and HEALTHY drinking water from any water source.

I wonder how many of these things they sell at $300 each?

MEMPHIS91 · 06-26-16, 09:02 PM

Over 2 years later lets bring this thread back to life.

I have a 2,300 square foot house that I want to keep the humidity at 40% during the summer.

I have looked over 80% of the links (that are still good) and am working on drawing up a diagram off how this should look.

I am constantly thinking "KEEP IT SIMPLE STUPID".

Anyone ever complete a unit that they can give me pointers on?

MEMPHIS91 · 06-26-16, 09:26 PM

NiHaoMike · 07-03-19, 09:12 PM

Looks like someone finally built a working proof of concept!

https://www.youtube.com/watch?v=R_g4nT4a28U

MN Renovator · 07-04-19, 07:24 PM

I know it's fairly simple but it looks more complex than the diagrams and discussions earlier. There are more thermal stages with 'heat gained here, but then pulled away here' stuff.

If I had the free time, I'd start a DIY solar liquid desiccant air conditioner manifesto, but time is massively lacking during the summer for me. In the future, perhaps.

jeff5may · 03-18-21, 02:08 PM

I don't know why I didn't check on this thread over the years. I actually tried out a couple of experimental rigs using this principle, and they both worked.

The first setup was built in one day at grandma's house and was gravity fed. Indoor dehumidifier section was an old storm window pane in a rubbermaid tote. I put a little submersible fountain pump in the bottom, feeding some drip irrigation plastic plumbing. Pump sent liquid up to the top of the window pane, and the drip hose distributed the liquid along the top horizontally. Liquid ran down the window pane into the tote. Maybe 10 gallons per hour flow rate.

I put an overflow hole in the tote, and a rubber grommet and garden hose fitting into the grommet. A garden hose ran along the floor outdoors. At the other end, I built a solar still like the "water honcho" pictured before. The evaporation vessel was a plastic kiddie pool spray painted black. I made a tepee out of some bamboo sticks and covered it with some old clear greenhouse film. The film was simply anchored to the ground with bricks.

To get the thing primed, I heated up a stock pot worth of water and added road runner ice melting salt to get a saturated solution. Put it in the tote, made more salt water solution, until the tote started to overflow. I hung a wad of salt in a sock and attached it to the tote so the salt was was suspended in the solution. Done.

The thing worked great all summer and into the fall. Grandma's basement became not musty, and her windows quit fogging up at night. Eventually, mother nature had her way with the greenhouse film and it got destroyed by hail.

05-24-14, 05:40 PM	#51
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	A new thread recently popped up, introducing a new concept for indirect evaporative cooling and dehumidification of buildings: http://ecorenovator.org/forum/geothe...25-energy.html The NREL paper describing the system, named the DEVAP, is here: http://search.nrel.gov/cs.html?url=h...nrel&n=4&la=en This thread got me thinking about the solar dehumidifier again. Indoors, a desiccant waterfall or forced air, swamp cooler type unit would dehumidify the air. Outdoors, a solar desalination tower could effectively remove as much water as one needed. Consider this description borrowed from Wikipedia: In 1993 a desalination plant was invented by Akhtar Iqbal Zuberi in Pakistan. Zuberi’s plant produces 40 liters of water per square meter per day. This is at least ten (10) times more productive than a conventional Horizontal Solar desalination plant. Water desalinated from this plant has 16 parts per million (ppm).[14] The structure is a raised tower made of cement, with a tank at the top. The whole plant is covered with glass of the same shape, but slightly larger, allowing for a gap between the cement tower and the glass. The tank is filled with saline water and water from an outside tank, drop by drop water enters the inner tank. The excessive water from the inner tank drips out onto the cement walls of the tower, from top to bottom. By solar radiation, the water on the wet surface and in the tank evaporate and condense on the inner surface of the glass cylinder and flow down onto the collecting drain channel. Meanwhile, the concentrated saline water drains out through a saline drain. In this process fresh saline water is continuously added to the walls from the top of the tower. After evaporation, the remaining saline water falls down and drains out continuously. The movement of water also increases the energy of molecules and increases the evaporation process. The increase in the tower’s height also increases the production. This plant’s base is 3.5 by 1.5 feet by 10 foot high, and gives about 12 liters of water per day.Built horizontally, a structured plant receives solar radiation at noon only. But Zuberi’s plant is a vertical tower and receives solar energy from sunrise till sunset. From early morning, it receives perpendicular radiation on one side of the plant. While at noon its top, gets radiation equivalent to the horizontal plant. From noon till sunset, the other side receives maximum radiation. By increasing the height, the tower plant receives more solar energy and the inner temperature increases as height increases. Ultimately this increases the water yield. A number of experiments have been conducted and a much more productive plant has been developed, with further work continuing. This project can be implemented anywhere there is ground water, brine or sea water available with suitable sun. During different experiments a plant six (6) 6 feet high can attain a temperature of 60 degrees Celsius, while a plant of ten (10) feet high can reach a temperature of up to 86 degree Celsius. http://www.energyglobe.info/awards/n...8#.U4FRUnJdV48 In this application, there is no need to save the purified water. Once the evaporation process has occurred, we are done. Therefore, a simple thermostat-controlled venting system could be used to "smokestack" the humid air from the top of the tower. This humid air would be replaced by ambient air at the bottom of the tower. With the original application, the shaded side of the plant would definitely condense more water. This assumes a tower made of concrete or bricks, but the tower may not need to be constructed as such. For example, a dark colored strip of towels or other wicking material sandwiched between suntuf panels may work well. The structure would need additional support, which may end up costing more than cinder blocks. As long as it got sun on both sides, it would collect the same energy from the sun. Last edited by jeff5may; 05-24-14 at 10:12 PM..

05-24-14, 10:19 PM	#52
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	For a test run or proof of concept, one could build a "water honcho". Water Honcho Portable Solar Powered Desalination and Water filter systems. Portable solar desalination, drinking water filter. FRESH and HEALTHY drinking water from any water source. I wonder how many of these things they sell at $300 each? Attached Thumbnails Last edited by jeff5may; 09-25-18 at 08:33 AM..

06-26-16, 09:02 PM	#53
MEMPHIS91 Journeyman EcoRenovator Join Date: Apr 2015 Location: Oxford, MS USA Posts: 496 Thanks: 69 Thanked 87 Times in 61 Posts	Over 2 years later lets bring this thread back to life. I have a 2,300 square foot house that I want to keep the humidity at 40% during the summer. I have looked over 80% of the links (that are still good) and am working on drawing up a diagram off how this should look. I am constantly thinking "KEEP IT SIMPLE STUPID". Anyone ever complete a unit that they can give me pointers on? __________________ שְׁמַע יִשְׂרָאֵל ה' אֱלֹהֵינוּ ה' אֶחָד

06-26-16, 09:26 PM	#54
MEMPHIS91 Journeyman EcoRenovator Join Date: Apr 2015 Location: Oxford, MS USA Posts: 496 Thanks: 69 Thanked 87 Times in 61 Posts	Attached Thumbnails __________________ שְׁמַע יִשְׂרָאֵל ה' אֱלֹהֵינוּ ה' אֶחָד

07-04-19, 07:24 PM	#56
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 940 Thanks: 41 Thanked 117 Times in 91 Posts	I know it's fairly simple but it looks more complex than the diagrams and discussions earlier. There are more thermal stages with 'heat gained here, but then pulled away here' stuff. If I had the free time, I'd start a DIY solar liquid desiccant air conditioner manifesto, but time is massively lacking during the summer for me. In the future, perhaps.

03-18-21, 02:08 PM	#57
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	I don't know why I didn't check on this thread over the years. I actually tried out a couple of experimental rigs using this principle, and they both worked. The first setup was built in one day at grandma's house and was gravity fed. Indoor dehumidifier section was an old storm window pane in a rubbermaid tote. I put a little submersible fountain pump in the bottom, feeding some drip irrigation plastic plumbing. Pump sent liquid up to the top of the window pane, and the drip hose distributed the liquid along the top horizontally. Liquid ran down the window pane into the tote. Maybe 10 gallons per hour flow rate. I put an overflow hole in the tote, and a rubber grommet and garden hose fitting into the grommet. A garden hose ran along the floor outdoors. At the other end, I built a solar still like the "water honcho" pictured before. The evaporation vessel was a plastic kiddie pool spray painted black. I made a tepee out of some bamboo sticks and covered it with some old clear greenhouse film. The film was simply anchored to the ground with bricks. To get the thing primed, I heated up a stock pot worth of water and added road runner ice melting salt to get a saturated solution. Put it in the tote, made more salt water solution, until the tote started to overflow. I hung a wad of salt in a sock and attached it to the tote so the salt was was suspended in the solution. Done. The thing worked great all summer and into the fall. Grandma's basement became not musty, and her windows quit fogging up at night. Eventually, mother nature had her way with the greenhouse film and it got destroyed by hail.