vacuum tube solar hot water heaters solar panels/turbines/electric radiant heaters
Question:
I have a commercial poultry operation and vacuum tube solar hot water heaters are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources… vacuum tube solar hot water heaters
How about a greenhouse? They’ll bulldoze my front lawn Sunday morning, two greenhouse kits will be delivered on Monday, and my farmer friend and I hope to have them assembled and filled with 500 tomato plants already started in other houses by April 15. Standard labor to put up a 30 x 96′ greenhouse in a field from scratch is 3 people, vacuum tube solar hot water heaters 1 day (if they know what they are doing
Putting the single 28 x 100′ pieces of plastic film on these 14′ wide x 9′ tall x 96′ long houses should take 2 people an hour or so, on a calm day. The house nearer the road will be covered with Bayer’s new clear 10-year Dureflex urethane film (tres elegant, non?), and the one behind it will have a $120 piece of standard 4-year cloudy greenhouse polyethylene film with UV inhibitors. Assembling these houses is fairly simple, like a large erector set, more like a tent than a building… Pound the 50″ “ground sleeve” pipes into the ground on 4′ centers, making the tops all the same level, then slip the single-piece bent hoop pipes into them, and attach the ridge pipe purlin with clamps. Then add 1×4 hip purlin boards to the hoops with U-clamps to secure the plastic film at the top of the roll up sides, about 4′ above the ground, and bolt a 1×8 perimeter skirtboard to the ground sleeves (we aren’t sure we need this, but we’ll probably do it anyway.) The endwalls will be plastic film over 2×4 framing on 4×8′ centers, with 1 or 2 plastic-film-covered 4×8′ doors. (We’ll put up the houses running EW with a 14′ space between them, and at some point we may add another arch between them to make them into a single 42′ x 96′ 4,032 ft^2 gutter-connected greenhouse with 3 arches and a little more post bracing under the gutters, like, 2×4s U-clamped to the vertical part of those pipes to prevent buckling, and maybe a soaker hose in each seamless gutter for snow melting, with the plastic films lapped over the center arch.) The next step is to stretch the large piece of plastic film over the frame squarely and secure it to the hip boards with deck screws and another 1×4 batten board, then lay the bottom edge of the film out flat on the ground about a foot on each side of the house, slide together each 100′ thinwall swedged pipe roller, attach a T-handle with a right angle clamp at one end, and duct tape (the universal solution vacuum tube solar hot water heaters the plastic to the roller pipe every 2′. vacuum tube solar hot water heaters The roller pipe ends up hanging from the film as it’s rolled up, so as I understand this, it only needs a handle at one end. The high tunnel ap note from ag prof Otho Wells at U New Hampshire says one person can roll up an entire 96′ side from one end in about 20 seconds (about 10 turns on the crank.) vacuum tube solar hot water heaters It might be fun to mechanize this with thermostatic control. We might slowly rotate another ridge purlin with a gearmotor, with some strings attached to that axle that loop under both side rollers from the inside of the house, with the other ends of the strings joining in a loop over the outside of the house between the bows, which would also serve to reduce wind flutter and plastic film fatigue. Bubblewalls are another option for shading and insulation. The hoops are 21′ lengths of standard schedule 40 3/4″ galvanized water pipe, (1.05″ OD) bent into a gothic arch shape (3 bends, like the outline of a typical house) by 2 people using a large outdoor plywood table with some simple 2×4 guides nailed to it as a jig. The manufacturer Mike Schwarz (302) 656-0276 is a low-overhead wholesale pipe vendor in Wilmington DE who got into the greenhouse business when he realized that he was selling a lot of his pipe with cosmetic defects to large local growers who were bending it into greenhouses. He doesn’t know much about the greenhouse business yet, and doesn’t realize that he’s in the solar heating business, and hasn’t applied for any million solar roof grants yet, so his prices are quite low, at 42 cents per square foot of “solar collector,” or about 0.4 cents per peak watt, about a hundred times less than photovoltaic power. Happy spring! vacuum tube solar hot water heaters
Response:
He doesn’t know much about the greenhouse business yet, and doesn’t realize that he’s in the solar heating business, and hasn’t applied for any million solar roof grants yet, so his prices are quite low, at 42 cents per square foot of “solar collector,” or about 0.4 cents per peak watt, about a hundred times less than photovoltaic power. vacuum tube solar hot water heaters
Oops, that’s a thousand times less. Happy spring! Nick
Response:
This might not work for a farm situation, but didn’t the Tightwad Gazette have an idea about using shelves with black-painted milk jugs filled with water as heat collectors? Hmmm, if it was for a chicken house, it might work, but not for a commercial property… vacuum tube solar hot water heaters
Response:
I have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy
sources.vacuum tube solar hot water heaters.. Birds put out a lot of heat on their own, so I’m a little curious about how far north you are. A green house built against the barn with a bunch of 55 gal drums painted black for thermal ballast and a bunch of black plastic hoses for heat pick up. Basic design similar to several solar hot water heaters published in old Mother Earth News magazines. Maybe someone in alt arch alt remembers that solar heated house a Japanese woman (?) designed for the west coast of Alaska. Not meaning to be critical, but could you break the news groups you post to into groups so people responding do not end up spamming a dozen ng’s? Another alternative might be to get one of those news reader programs that lets you set follow-ups to a single newsgroup of your choice while posting to many. You’ll get more responses from people who might otherwise not post. Posting from misc rural vacuum tube solar hot water heaters
Response:
I have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources… Birds put out a lot of heat on their own…
About 16 Btu/h of sensible and 18 of latent heat (chicken sweat
for an ASHRAE-standard 2-pound broiler raised at 60 F on litter. A green house built against the barn with a bunch of 55 gal drums painted black for thermal ballast and a bunch of black plastic hoses…
…might work better with lots of insulation vs glazing with overheating during the day and lots of heat loss at night. And who needs thermal mass with the chickens doing the heating? Ventilation would help, eg a couple of Jade Mountain’s FC115 $54 Thermofor passive vent openers opening some hinged foamboard panels up to 15 pounds and 15″ when the temperature reaches 70 F. (I have no financial interest in Jade Mountain, BTW.) Basic design similar to several solar hot water heaters published in old Mother Earth News magazines.
Why heat hot water? :vacuum tube solar hot water heaters Those designs seem inefficient and labor-intensive and not easy to replicate (“Charlie and me drove around all day until we found this bathtub, see? It wuz mostly buried in mud, and we got out our shovels and crowbars…”) Not meaning to be critical, but could you break the news groups you post to into groups so people responding do not end up spamming a dozen ng’s? vacuum tube solar hot water heaters
No. Spamming is commercial. Few of my postings are, and it seems to me they are relevant to the crossposted groups. Others might observe the same discipline in their posted responses, removing irrelevant newsgroups as needed (eg alt.solar.thermal from “Hydrogen revisited.”) Crossposting doesn’t waste bandwidth or human time, since you’ll only see this posting once even if you subscribe to all the newsgroups, and it encourages a more interdisciplinary view of the world, global piracy, vs lots of insular cross-eyed cargo cults, like PV enthusiasts who want to heat houses with electric resistance devices. Happy Spring, vacuum tube solar hot water heaters
Response:
vacuum tube solar hot water heaters Not meaning to be critical, but could you break the news groups you post to into groups so people responding do not end up spamming a dozen ng’s? No. Spamming is commercial. Few of my postings are, and it seems to me they are relevant to the crossposted groups. Others might observe the same discipline in their posted responses, removing irrelevant newsgroups as needed (eg alt.solar.thermal from “Hydrogen revisited.”) Crossposting doesn’t waste bandwidth or human time, since you’ll only see this posting once even if you subscribe to all the newsgroups, and it encourages a more interdisciplinary view of the world, global piracy, vs lots of insular cross-eyed cargo cults, like PV enthusiasts who want to heat houses with electric resistance devices. Happy Spring, Nick
Anytime you ask a question and make it impossible for a person to reply to you without posting to a dozen newsgroups, you are spamming. Please include a VALID Email address that can accept replies. Every reply goes to a dozen places, and I bet most of the replies are complaining about your crossposting…
Response:
I have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources… Birds put out a lot of heat on their own… About 16 Btu/h of sensible and 18 of latent heat (chicken sweat
for an ASHRAE-standard 2-pound broiler raised at 60 F on litter.
That’s useful info. I hadn’t seen numbers on the thermal output of birds before. I’ve used my pet peacock as a foot warmer on cold nights for years. Higher heat output than a cat or dog. The cost to operate is chickenfeed. If I could just solve the polution problem…vacuum tube solar hot water heaters
Response:
I have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources…
With all due respect to Nick(the greenhouse man), the most obvious thing for you to do, that could solve 2 problems at once, is to build a chicken poop digester, and use the methane to heat the buildings / run a generator, whatever. I don’t know where to suggest you start looking but I think that it would be your best long-term bet.
Response:
vacuum tube solar hot water heaters
Religious nuts and so on. But in my mind, if the subject matter is relevant to more than one group, it’s fine and useful to crosspost. As far as the user only seeing any given cross-post that’s true with certain news readers. Not all have that ability.
I don’t know of any such readers. Perhaps you are looking at the same thing posted individually to multiple newsgroups, which can be a pain, vs crosspostings. Incidentally, one is not “forced to reply” to all groups, if a) one recognizes an obvious email address fudge like “sanspam” and removes it to reply by email, or b) removes irrelevant newsgroups from the header upon responding with a posting. More than ’nuff said on this subject, vacuum tube solar hot water heaters
Response:
The normal setup for forced air is both outlet and inlet ducts in the floor. This is fine when the heat source is the furnace, but for circulating solar heat not so fine, because the warm air will simply sit on the ceiling while the cold air scoots along the floor. So you need powerful ceiling fans to drive the warm air down towards the registers. Or alternately you could install additional ducts to pick up heat from the ceiling. Hope this helps I want to reduce our heating costs. We live in southwestern Ontario. We have good insulation and the house is sealed quite well. I want to construct a solar heat collector and already have the plans drawn up…. Now, I am curious if I could use ducts to connect the solar heat collector to my forced air furnace ductwork to distribute the heat throughout the house,
“One good thing about self-pity…you don’t have to doubt its sincerity.”
Response:
The normal setup for forced air is both outlet and inlet ducts in the floor. This is fine when the heat source is the furnace, but for circulating solar heat not so fine, because the warm air will simply sit on the ceiling while the cold air scoots along the floor.
Would the location of the heat source be that important? Why wouldn’t the warm air from the furnace decide to go sit on the ceiling too? So you need powerful ceiling fans to drive the warm air down towards the registers.
Ceiling fans aren’t that powerful. Grainger’s $140 110W 4F424 56″ diameter reversible fan moves 27,500 cfm, equivalent to about 28 20″ window box fans. How much airflow do we need?vacuum tube solar hot water heaters
Response:
The normal setup for forced air is both outlet and inlet ducts in the floor. This is fine when the heat source is the furnace, but for circulating solar heat not so fine, because the warm air will simply sit on the ceiling while the cold air scoots along the floor. Would the location of the heat source be that important? Why wouldn’t the warm air from the furnace decide to go sit on the ceiling too?
When the furnace is working, hot air is pushed out the supply ducts, and cold air is being pulled down the return ducts. The air circulates vertically within the room, first rising to the ceiling and then settling to the floor as it cools before returning to the furnace. However, when the supply registers have air at the same temperature as the return ducts, the air simply slides along the floor between the ducts, and does not mix with the warmer ceiling air (not all that well, anyway). Hope I’m explaining this OK. Maybe someone else could do a better job. So you need powerful ceiling fans to drive the warm air down towards the registers. Ceiling fans aren’t that powerful. Grainger’s $140 110W 4F424 56″ diameter reversible fan moves 27,500 cfm, equivalent to about 28 20″ window box fans. How much airflow do we need?
That’s plenty powerful. However, the average house probably needs more than one, in different rooms. – “One good thing about self-pity…you don’t have to doubt its sincerity.”
Response:
The normal setup for forced air is both outlet and inlet ducts in the floor. This is fine when the heat source is the furnace, but for circulating solar heat not so fine, because the warm air will simply sit on the ceiling while the cold air scoots along the floor. Would the location of the heat source be that important? Why wouldn’t the warm air from the furnace decide to go sit on the ceiling too? When the furnace is working, hot air is pushed out the supply ducts, and cold air is being pulled down the return ducts. The air circulates vertically within the room, first rising to the ceiling and then settling to the floor as it cools before returning to the furnace.
I think the air in the room is mostly well-mixed by the energy in the airstream imparted by the furnace blower, vs temperature differences, in this case, vs a woodstove in the center of a room. However, when the supply registers have air at the same temperature as the return ducts, the air simply slides along the floor between the ducts, and does not mix with the warmer ceiling air (not all that well, anyway).
I don’t think it does that, in fact. It seems to me that the room air would still mix well, as long as the same air velocity exited the supply registers, which are rated for “throw” at certain velocities. With no obstructions, the moving airstream mixes the room air like open windows cause wind all over a car or a bathtub tap heats all of the bathwater. vacuum tube solar hot water heaters
Response:
- Hide quoted text — Show quoted text – I have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources… Birds put out a lot of heat on their own… About 16 Btu/h of sensible and 18 of latent heat (chicken sweat
for an ASHRAE-standard 2-pound broiler raised at 60 F on litter. That’s useful info. I hadn’t seen numbers on the thermal output of birds before. I’ve used my pet peacock as a foot warmer on cold nights for years. Higher heat output than a cat or dog. The cost to operate is chickenfeed. If I could just solve the polution problem… vacuum tube solar hot water heaters
vacuum tube solar hot water heaters
Response:
Now, I am curious if I could use ducts to connect the solar heat collector to my forced air furnace ductwork to distribute the heat throughout the house, specifically the main level?
One simple technique is to install floor vents in your main level. That way, you will have warm air rising into your main living space without the need for turning on energy-consuming fans. You can also employ water tanks of some sort in direct solar gain (the sun shines directly on them) if you want to level out the heat distribution throughout the day and night. Cheers, Will Stewart
Response:
Birds put out a lot of heat on their own… About 16 Btu/h of sensible and 18 of latent heat (chicken sweat
for an ASHRAE-standard 2-pound broiler raised at 60 F on litter. That’s useful info. I hadn’t seen numbers on the thermal output of birds before…
The ASHRAE Handbook of Fundamentals (HOF) has many cheerful facts about animal heat production, eg sheep heat as a function of air temperature and fleece length. …Wonder, though, which BTU the writer is using, the BTU [international] or BTU [therm]?
Looks like it hardly matters. They don’t differ a great deal, though. 16 BTU international would be equivalent to 4.689 watts and 16 therms 4.686 watts.
Whoa, those are apples and oranges! Btu’s are energy, and watts are power, the time rate of change of energy, like miles vs miles per hour. In other words, Energy = Power x Time. A watt-hour is 3.41 Btu, so 16 Btu is 4.69 watt-hours or 0.00469 kilowatt hours (kWh.) Also, a “therm” is 100K Btu, roughly equivalent to a gallon of oil, in natural gas circles. Anyone want to bother to calculate practical considerations such as how many chickens it would take to produce enough chicken manure to produce enough methane to produce 36 kilowatts of usable power?
The smallest creature listed in the NRAES On-Farm Biogas Production book is a 130 pound feeder pig who produces 0.16 cubic feet (a 6.5″ cube
of manure per day which makes 5.6 ft^3/day of biogas which can make 0.2 kWh/day of electrical energy, ie 8.3 watts, on a continuous basis (vs. 4.83×130^0.75 = 186 watts of heat from the pig, according to the HOF), so producing 36 kW on a continuous basis requires 4,320 pigs, which could make you unpopular with the neighbors. Aerobically composting poop or raising animals for heat production seems like a much better deal, energy-wise, and requires simpler equipment. Nick Expired US Patent No. 3,933,628 (US Patents are available for $3 each from The Superintendent of Patents and Trademarks, Washington, DC 20231) describes a “Method and Apparatus for the Anaerobic Digestion of Decomposable Organic Materials,” issued to inventor Frederick T. Varani of Golden, CO on Jan 20, 1976, and assigned to Bio-Gas of Colorado. He describes a way to make methane in conjunction with a 100,000-cow feedlot, using 2 EPDM-rubber-lined trenches, each 700 feet long x 80 feet wide x 40 feet deep. The trenches have self-inflated translucent “solar covers” and cost $0.02 per gallon, including excavation. The feedlot generates 3.3 million pounds of manure each day, along with 6 million pounds of water and 200,000 pounds of carbon, which the digesters turn into about 7 million cubic feet of methane per day with a heating value of 277 million Btu per hour, along with 2 1/2 million cubic feet of CO2. The digesters contain heat exchangers for temperature control… The fermentation reaction will proceed satisfactorily at any temperature between approximately 90 F and 115 F, however, between these limits many different species of bacteria become active, each in its own particular temperature zone carved out of this broader range. In other words, the digestion process is basically an equilibrium between many species of bacteria that live upon various substrates (food) and on one another. Changes in temperature cause this equilibrium to shift and some of the more temperature-sensitive species die off or become less active while others assume a more active role… Ideally, methanogenic bacteria should be kept at about 95 F and the temperature range should not be allowed to vary more than +/- 2 F per day from this base temperature if temperature shock is to be avoided. This could be a municipal sewage treatment system, without the cows, or an efficient way to combine sewage treatment and long term passive solar thermal storage, for a single house, on a smaller scale. Pages 825-826 of Metcalf and Eddy’s 1991 _Wastewater Engineering_ say Typical values [of gas production] vary from 12-18 ft^3/lb of volatile solids destroyed… Gas production can also be crudely estimated on a per capita basis. The normal yield is 0.6 to 0.8 ft^3/person/day (15 to 22 m^3/1000 persons/day) in primary plants treating normal domestic wastewater. In secondary plants, the gas production is increased to 1.0 ft^3/person/day… Because digester gas is typically about 65% methane, the low heating value of digester gas is approximately 600 Btu/ft^3 (22,400 kJ/m^3)… In large plants digester gas may be used as fuel for boiler and internal combustion engines, which are in turn used for pumping wastewater, operating blowers, and generating electricity… Because digester gas contains hydrogen sulfide, particulates and water vapor, the gas frequently has to be cleaned in dry or wet scrubbers before it is used in internal combustion engines.
Response:
vacuum tube solar hot water heatersI have a commercial poultry operation and are looking for economical ways to heat my farm, If possible, I would like use renewable energy sources… 2== However, differences can be quite significant when talking large numbers. The chicken farmer [rancher?] estimated his energy requirement as 36,000 watts, or 36 kw, did he not? 3== Someone proposed that the fecal output from the chickens could be used to produce methane, which could be used as a source of heat, tractor fuel, etc. Anyone want to bother to calculate practical considerations such as how many chickens it would take to produce enough chicken manure to produce enough methane to produce 36 kilowatts of usable power?
A “large commercial poultry operation” implies thousands of birds, and daily fecal removal/disposal. Disposal of said fecal matter is a huge problem. Dumping it into pit after pit to degrade or dumping it into methane digester tanks for relatively quick disposal AND recieving all the gas you need for motor fuel, generators, heat, plus hi-grade fertilizer. Or the effort expended in collecting the daily output of chicken manure and transferring it to the digester, especially if the chickens are free-range and not battery chickens?
as above, effort has to be expended (poop has to be removed), and there are no “large commercial poultry operation” with “free ranging birds” in this country that i’ve ever seen. don’t know how it’s done ‘down-under’, but here commercial chicken/turkey ‘farms’ are huge, low sheds housing 10k+ birds, in cages. feeding is automatic, fecal matter removal is MANDATORY by law (besides, you’d be up to your *** in days) for sanitary reasons. ….Now if the chickens could be toilet trained to go to the digester input, might be practical. However, I have never heard of a toilet-trained bird of any description. There is a reason for the term “bird brained”. 4== Someone suggested running a tractor on methane. If they look into it, think they will find that this isn’t all that easy either. 5== Chicken manure is one of the highest energy natural fertilizers. My suggestion to the chicken farmer is to simply collect the chicken manure and sell it for this purpose and to buy the electricity and fuel he needs. vacuum tube solar hot water heaters
If you check with your Brit friends, they can tell you of all the poultry/dairy/goat/pig farms that have been energy self-sufficient since before WWII, all on methane. also, there are commercial digester manufacturers in AU., GB, US and many other countries.vacuum tube solar hot water heaters
Response:
vacuum tube solar hot water heaters However, differences can be quite significant when talking large numbers. The chicken farmer [rancher?] estimated his energy requirement as 36,000 watts, or 36 kw, did he not? 3== Someone proposed that the fecal output from the chickens could be used to produce methane, which could be used as a source of heat, tractor fuel, etc. Anyone want to bother to calculate practical considerations such as how many chickens it would take to produce enough chicken manure to produce enough methane to produce 36 kilowatts of usable power? Or the effort expended in collecting the daily output of chicken manure and transferring it to the digester, especially if the chickens are free-range and not battery chickens? ….Now if the chickens could be toilet trained to go to the digester input, might be practical. However, I have never heard of a toilet-trained bird of any description. There is a reason for the term “bird brained”. 4== Someone suggested running a tractor on methane. If they look into it, think they will find that this isn’t all that easy either. 5== Chicken manure is one of the highest energy natural fertilizers. My suggestion to the chicken farmer is to simply collect the chicken manure and sell it for this purpose and to buy the electricity and fuel he needs.
Bacause of its low C/N ratio, chicken manure would give rise to volatile nitrogen comopounds as it rotted, and the fertilizer value would drop. If you added a high-C waste product to the mix (Ideal mix is 30:1 C:N), you could capture all the nitrogen, recover some methane, and make a stable compost which would be more valuable than the original chicken manure.
Response:
vacuum tube solar hot water heaters
And I’m curious as to if a black tin roof could be arranged to sit 100mm proud of an insulating layer and hot air collected at the ridge and blown down in? If a DC fan was run direct off a solar cell array it would only work when required; ie when the sun shines. In hot weather the system could be used to pull a cooling draught into the building, by the suction of hot air rising to the ridge and being allowed to escape, and the output of the solar cell used to run well…a small fridge? vacuum tube solar hot water heaters
Response:
According to Producing your own Power (etd by Carol Hupping Stoner) 100 chickens will produce between 12-24 qubic ft of methane per day..hope this helps Carl – vacuum tube solar hot water heaters Birds put out a lot of heat on their own… About 16 Btu/h of sensible and 18 of latent heat (chicken sweat
for an ASHRAE-standard 2-pound broiler raised at 60 F on litter. That’s useful info. I hadn’t seen numbers on the thermal output of birds before… The ASHRAE Handbook of Fundamentals (HOF) has many cheerful facts about animal heat production, eg sheep heat as a function of air temperature and fleece length. …Wonder, though, which BTU the writer is using, the BTU [international] or BTU [therm]? Looks like it hardly matters. They don’t differ a great deal, though. 16 BTU international would be equivalent to 4.689 watts and 16 therms 4.686 watts. Whoa, those are apples and oranges! Btu’s are energy, and watts are power, the time rate of change of energy, like miles vs miles per hour. In other words, Energy = Power x Time. A watt-hour is 3.41 Btu, so 16 Btu is 4.69 watt-hours or 0.00469 kilowatt hours (kWh.) Also, a “therm” is 100K Btu, roughly equivalent to a gallon of oil, in natural gas circles. Anyone want to bother to calculate practical considerations such as how many chickens it would take to produce enough chicken manure to produce enough methane to produce 36 kilowatts of usable power? The smallest creature listed in the NRAES On-Farm Biogas Production book is a 130 pound feeder pig who produces 0.16 cubic feet (a 6.5″ cube
of manure per day which makes 5.6 ft^3/day of biogas which can make 0.2 kWh/day of electrical energy, ie 8.3 watts, on a continuous basis (vs. 4.83×130^0.75 = 186 watts of heat from the pig, according to the HOF), so producing 36 kW on a continuous basis requires 4,320 pigs, which could make you unpopular with the neighbors. Aerobically composting poop or raising animals for heat production seems like a much better deal, energy-wise, and requires simpler equipment. Nick Expired US Patent No. 3,933,628 (US Patents are available for $3 each from The Superintendent of Patents and Trademarks, Washington, DC 20231) describes a “Method and Apparatus for the Anaerobic Digestion of Decomposable Organic Materials,” issued to inventor Frederick T. Varani of Golden, CO on Jan 20, 1976, and assigned to Bio-Gas of Colorado. He describes a way to make methane in conjunction with a 100,000-cow feedlot, using 2 EPDM-rubber-lined trenches, each 700 feet long x 80 feet wide x 40 feet deep. The trenches have self-inflated translucent “solar covers” and cost $0.02 per gallon, including excavation. The feedlot generates 3.3 million pounds of manure each day, along with 6 million pounds of water and 200,000 pounds of carbon, which the digesters turn into about 7 million cubic feet of methane per day with a heating value of 277 million Btu per hour, along with 2 1/2 million cubic feet of CO2. The digesters contain heat exchangers for temperature control… The fermentation reaction will proceed satisfactorily at any temperature between approximately 90 F and 115 F, however, between these limits many different species of bacteria become active, each in its own particular temperature zone carved out of this broader range. In other words, the digestion process is basically an equilibrium between many species of bacteria that live upon various substrates (food) and on one another. Changes in temperature cause this equilibrium to shift and some of the more temperature-sensitive species die off or become less active while others assume a more active role… Ideally, methanogenic bacteria should be kept at about 95 F and the temperature range should not be allowed to vary more than +/- 2 F per day from this base temperature if temperature shock is to be avoided. This could be a municipal sewage treatment system, without the cows, or an efficient way to combine sewage treatment and long term passive solar thermal storage, for a single house, on a smaller scale. Pages 825-826 of Metcalf and Eddy’s 1991 _Wastewater Engineering_ say Typical values [of gas production] vary from 12-18 ft^3/lb of volatile solids destroyed… Gas production can also be crudely estimated on a per capita basis. The normal yield is 0.6 to 0.8 ft^3/person/day (15 to 22 m^3/1000 persons/day) in primary plants treating normal domestic wastewater. In secondary plants, the gas production is increased to 1.0 ft^3/person/day… Because digester gas is typically about 65% methane, the low heating value of digester gas is approximately 600 Btu/ft^3 (22,400 kJ/m^3)… In large plants digester gas may be used as fuel for boiler and internal combustion engines, which are in turn used for pumping wastewater, operating blowers, and generating electricity… Because digester gas contains hydrogen sulfide, particulates and water vapor, the gas frequently has to be cleaned in dry or wet scrubbers before it is used in internal combustion engines.
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…when the supply registers have air at the same temperature as the return ducts, the air simply slides along the floor between the ducts, and does not mix with the warmer ceiling air… You lost me when you said that supply ducts and return ducts could have the same temperature. Wouldn’t that result in a thermostatic shut off of fan and furnace?
We want the fan on as long as the sunspace is warm and the house needs heat. Long before there were forced air furnaces, there were “gravity flow” systems that simply used the principle of convection…
vacuum tube solar hot water heaters
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vacuum tube solar hot water heatersThe normal setup for forced air is both outlet and inlet ducts in the floor. This is fine when the heat source is the furnace, but for circulating solar heat not so fine, because the warm air will simply sit on the ceiling while the cold air scoots along the floor. Would the location of the heat source be that important? Why wouldn’t the warm air from the furnace decide to go sit on the ceiling too? When the furnace is working, hot air is pushed out the supply ducts, and cold air is being pulled down the return ducts. The air circulates vertically within the room, first rising to the ceiling and then settling to the floor as it cools before returning to the furnace. However, when the supply registers have air at the same temperature as the return ducts, the air simply slides along the floor between the ducts, and does not mix with the warmer ceiling air (not all that well, anyway). Hope I’m explaining this OK. Maybe someone else could do a better job.
You lost me when you said that supply ducts and return ducts could have the same temperature. Wouldn’t that result in a thermostatic shut off of fan and furnace? Long before there were forced air furnaces, there were “gravity flow” systems that simply used the principle of convection. Houses were only as comfortable as the furnace fire was <big, and/or the insulation kept the heat in. With solar heating, the same principle should work if the heat storage source is in the lowest part of the house. Without any blowers, air expands as it is heated, and becomes relatively lighter than the cold dense air which falls in replacement of the the hot air, which rises. Convection is a relatively constant circular vertical flow, not just a matter of hot air rising and staying up there forever. It can’t be as hot as the newly heated air on its way up, which forces the slightly cooler air back down toward the heat source, endlessly. My approach will always be to let convection happen, with appropriate ducts/registers/whatever…. – Hide quoted text — Show quoted text – So you need powerful ceiling fans to drive the warm air down towards the registers. Ceiling fans aren’t that powerful. Grainger’s $140 110W 4F424 56″ diameter reversible fan moves 27,500 cfm, equivalent to about 28 20″ window box fans. How much airflow do we need? That’s plenty powerful. However, the average house probably needs more than one, in different rooms. – “One good thing about self-pity…you don’t have to doubt its sincerity.”
vacuum tube solar hot water heaters
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The problem is that they come with their own amplifiers. I can’t believe the rock-concert sounds that come out of that tiny head! vacuum tube solar hot water heaters
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The problem is that they come with their own amplifiers. I can’t believe the rock-concert sounds that come out of that tiny head! vacuum tube solar hot water heaters
Years ago I went with my best friend first thing one spring morning to drive her 81-year-old granny for admission to hospital. When we arrived, the granny said she was almost ready, but we *must* have a cup of tea (old Scottish lady, didn’t go anywhere without her morning tea) and that she still had to feed her bird. When she went to the other room to feed the bird, and I guess took the cover off the cage, there was a sudden burst of sound that made me spurt tea all over. I’d thought she had a canary. I just had to go see what kind of bird it really was and/or how many birds were really in there! It *was* a canary, and only one. Seeing me still mopping the front of my shirt with a napkin, the granny figured out what had happened and explained: ”I used to have two canaries. When the other one died, this one was silent for about a week. Then I guess she made up her mind that it was her responsibility to make enough song and noise for two, and she’s been singing and making a racket like that every day since. Sometimes it’s quite a nuisance, but mostly I love it. When Pappy goes, if he goes before me, I hope I can take the same attitude and spread enough joy for two.” Thanks, Janis, for bringing back the memory of a lovely old couple, now both long gone. Melanie ObfrugalNewPet(s): Some wonderful pets are available at animal shelters for much less than pet stores or breeders or classified ads are asking, and those at most animal shelters have been checked over for health problems and suitability for adoption (temperament, etc.) Here, the SPCA also arranges for spay or neutering (if needed) at a discount rate, and though they don’t advertise it, they often have an “instore special” of two adoptions for the price of one.
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preferred is calcium chloride hexahydrate (1 pt CaCl, 6 pts H2O). melts when sun shines (absorbs energy) and freezes when it cools down (releases energy). the energy absorbed/released is the CaCl.6H2O ‘heat of fusion’. can’t find the number but typically stated in kilo-calories/gram. definitely ‘much’. in english, the melting/freezing of 1 gram of CaCl.6H2O will absorb/release ‘much’ energy without it’s temperature changing from it’s freezing point (30 C). at room temp, water will only rise 1 deg(C) for each calorie absorbed and release the same when the room gets cooler. if you try to store a kilo-calorie in a gram water you’d have to raise the temp 1000 deg. with the CaCl, you only need to melt it to store ‘much’ heat. sorry i can’t seem to find the heat of fusion for CaCl.6H2O but it’s certainly more than the 1 cal/gram you get heating water. wray This might not work for a farm situation, but didn’t the Tightwad Gazette have an idea about using shelves with black-painted milk jugs filled with water as heat collectors? Hmmm, if it was for a chicken house, it might work, but not for a commercial property.vacuum tube solar hot water heaters
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