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BTU's per dollar
Well, today was our first rainy cold overcast day of the year. It really
looks like November today. At 2:30 PM the patio was 50F, the GH was 62F I turned off the overhead misters so the water doesn't make damp down everything, making them cold and clammy, and I turned on the little electric space heater. HA! Talk about useless! So I guess I will go to Grainger, get the gas valve assembly and fire up the Southern Burner. Drat. Why does this sort of thing always happen on a holiday weekend when everything's closed? K Barrett "alpickrel" wrote in message oups.com... You were smart. My old hoophouse frame is still standing right next to the greenhouse. It is 15 x 30 (or so). Just the metal frame right now. It has grapes growing on it. I have had the idea in the back of my head to cover it with insualtion and black plastic water circulating tubes and turn it into a giant solar hot water collector/storage unit of some kind that I can then use at night to pump the heat into the greenhouse next to it. The heat sink can't be IN the greenhouse because to be of any real use, whatever goes in there...a pool or whatever..., it has to be able to get hot enough to be of use long after the sun gets off it, so plants won't be able to be grown in there with it. (now I get K Barrett's joke about lying to herself about her barrel of water.) I was staring at my electrical subpanel for the greenhouse this afternoon and wondering what it would take to run a line large enough to power an electric heater that would make me feel like I was not lying to myself when I plugged it in. I still think a good option is to find a way to drag a big warm blanket over the greenhouse every night. I also wondered when somebody with the know how will get the bright idea of turning clear 6 mil greenhouse plastic film into a giant solar electric collector sheet. I mean I spend all summer trying to REMOVE light and heat. It would be nice to be doing something useful with it. There is talk of a spray-on solar panel. On Nov 9, 8:05 pm, "Pat Brennan" wrote: When I put up my last greenhouse I needed a new power service. I had the power company run an extra 200 amps of service and used it for my backup heating system. The thought that oil now costs the same as that backup system is as you said scary stuff. This greenhouse is one third the size of my others. As we started to get into heating season I was able to empty it and turn it off. As oil continues to rise I am wondering if between the store (which closes at the end of the month) and the little greenhouse if I can close a big greenhouse. And if I do not need the greenhouse, I am also wondering how I turn it into a solar collector. I think I need to do some reading on heat pump and transfer systems and swimming pools. Pat |
BTU's per dollar
Is anyone using this method? Sounds intriguing. Knowing the length of the
trench to be effective would be helpful. And what about ducting the hot air from the greenhouse down through the trench? I can see this method working on a small hobby greenhouse. "Ray B" wrote in message news:6ajZi.1890$cD.932@trndny08... About the least expensive heating method (it's good for cooling, too) I've ever heard of was published in the AOS Bulletin in the late '70's or '80's. A guy had an extended trench dug 6' into the ground (or some depth well-below his frost line), and made a long duct of large, unglazed clay sewer pipe. One end came up through the floor of the greenhouse, and the other end was enclosed in a structure above ground. The inlet end was covered with a mesh and filter to prevent all but air from entering. A thermostatically-controlled fan in the GH drew air through the submerged pipe, where the natural subsurface temperature was in the low-'60's F year round, which is certainly plenty warm for nighttime, with solar heating boosting the daytime temp. In the summer, he would switch to a cooling thermostat, drawing that same cool air. That's certainly less maintenance than a swamp cooler! The article also discussed how the unglazed clay absorbed the condensed humidity in the summer, and moistened the air in the winter, but I don't recall details. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! "alpickrel" wrote in message oups.com... You were smart. My old hoophouse frame is still standing right next to the greenhouse. It is 15 x 30 (or so). Just the metal frame right now. It has grapes growing on it. I have had the idea in the back of my head to cover it with insualtion and black plastic water circulating tubes and turn it into a giant solar hot water collector/storage unit of some kind that I can then use at night to pump the heat into the greenhouse next to it. The heat sink can't be IN the greenhouse because to be of any real use, whatever goes in there...a pool or whatever..., it has to be able to get hot enough to be of use long after the sun gets off it, so plants won't be able to be grown in there with it. (now I get K Barrett's joke about lying to herself about her barrel of water.) I was staring at my electrical subpanel for the greenhouse this afternoon and wondering what it would take to run a line large enough to power an electric heater that would make me feel like I was not lying to myself when I plugged it in. I still think a good option is to find a way to drag a big warm blanket over the greenhouse every night. I also wondered when somebody with the know how will get the bright idea of turning clear 6 mil greenhouse plastic film into a giant solar electric collector sheet. I mean I spend all summer trying to REMOVE light and heat. It would be nice to be doing something useful with it. There is talk of a spray-on solar panel. On Nov 9, 8:05 pm, "Pat Brennan" wrote: When I put up my last greenhouse I needed a new power service. I had the power company run an extra 200 amps of service and used it for my backup heating system. The thought that oil now costs the same as that backup system is as you said scary stuff. This greenhouse is one third the size of my others. As we started to get into heating season I was able to empty it and turn it off. As oil continues to rise I am wondering if between the store (which closes at the end of the month) and the little greenhouse if I can close a big greenhouse. And if I do not need the greenhouse, I am also wondering how I turn it into a solar collector. I think I need to do some reading on heat pump and transfer systems and swimming pools. Pat |
BTU's per dollar
I'm thinking about it....
Depth, length, surface area of the pipe, and air volume would all be in consideration. I would think that multiple, smaller-diameter (4", 6" ?) pipes might be better than one large-diameter one (greater surface-to-volume ratio, but more resistance to air flow). I would guess that venting the hot greenhouse air in the summer should be up and out, not down through the buried pipes. Cool air would be drawn in from the pipes by natural convection, even without a fan. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! "Mark_OK" wrote in message ... Is anyone using this method? Sounds intriguing. Knowing the length of the trench to be effective would be helpful. And what about ducting the hot air from the greenhouse down through the trench? I can see this method working on a small hobby greenhouse. "Ray B" wrote in message news:6ajZi.1890$cD.932@trndny08... About the least expensive heating method (it's good for cooling, too) I've ever heard of was published in the AOS Bulletin in the late '70's or '80's. A guy had an extended trench dug 6' into the ground (or some depth well-below his frost line), and made a long duct of large, unglazed clay sewer pipe. One end came up through the floor of the greenhouse, and the other end was enclosed in a structure above ground. The inlet end was covered with a mesh and filter to prevent all but air from entering. A thermostatically-controlled fan in the GH drew air through the submerged pipe, where the natural subsurface temperature was in the low-'60's F year round, which is certainly plenty warm for nighttime, with solar heating boosting the daytime temp. In the summer, he would switch to a cooling thermostat, drawing that same cool air. That's certainly less maintenance than a swamp cooler! The article also discussed how the unglazed clay absorbed the condensed humidity in the summer, and moistened the air in the winter, but I don't recall details. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! "alpickrel" wrote in message oups.com... You were smart. My old hoophouse frame is still standing right next to the greenhouse. It is 15 x 30 (or so). Just the metal frame right now. It has grapes growing on it. I have had the idea in the back of my head to cover it with insualtion and black plastic water circulating tubes and turn it into a giant solar hot water collector/storage unit of some kind that I can then use at night to pump the heat into the greenhouse next to it. The heat sink can't be IN the greenhouse because to be of any real use, whatever goes in there...a pool or whatever..., it has to be able to get hot enough to be of use long after the sun gets off it, so plants won't be able to be grown in there with it. (now I get K Barrett's joke about lying to herself about her barrel of water.) I was staring at my electrical subpanel for the greenhouse this afternoon and wondering what it would take to run a line large enough to power an electric heater that would make me feel like I was not lying to myself when I plugged it in. I still think a good option is to find a way to drag a big warm blanket over the greenhouse every night. I also wondered when somebody with the know how will get the bright idea of turning clear 6 mil greenhouse plastic film into a giant solar electric collector sheet. I mean I spend all summer trying to REMOVE light and heat. It would be nice to be doing something useful with it. There is talk of a spray-on solar panel. On Nov 9, 8:05 pm, "Pat Brennan" wrote: When I put up my last greenhouse I needed a new power service. I had the power company run an extra 200 amps of service and used it for my backup heating system. The thought that oil now costs the same as that backup system is as you said scary stuff. This greenhouse is one third the size of my others. As we started to get into heating season I was able to empty it and turn it off. As oil continues to rise I am wondering if between the store (which closes at the end of the month) and the little greenhouse if I can close a big greenhouse. And if I do not need the greenhouse, I am also wondering how I turn it into a solar collector. I think I need to do some reading on heat pump and transfer systems and swimming pools. Pat |
BTU's per dollar
How well do you think the flexible, corrugated, black plastic septic-system
pipe would work? It's fairly thin-walled, so the heat transfer would be fairly good I would think, and by being flexible, you could bury a bunch of coils, reducing the amount of property that would have to be dug up. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! |
BTU's per dollar
I don't see why that wouldn't work and would be cheaper and easier to work
with than the clay type. "Ray B" wrote in message news:4rZZi.4449$NC.3728@trndny07... How well do you think the flexible, corrugated, black plastic septic-system pipe would work? It's fairly thin-walled, so the heat transfer would be fairly good I would think, and by being flexible, you could bury a bunch of coils, reducing the amount of property that would have to be dug up. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! |
BTU's per dollar
I would guess that venting the hot greenhouse air in the summer should be up and out, not down through the buried pipes. Cool air would be drawn in from the pipes by natural convection, even without a fan. I was just thinking of keeping the humidity level up by recirculating the air, but I see your point. Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! "Mark_OK" wrote in message ... Is anyone using this method? Sounds intriguing. Knowing the length of the trench to be effective would be helpful. And what about ducting the hot air from the greenhouse down through the trench? I can see this method working on a small hobby greenhouse. "Ray B" wrote in message news:6ajZi.1890$cD.932@trndny08... About the least expensive heating method (it's good for cooling, too) I've ever heard of was published in the AOS Bulletin in the late '70's or '80's. A guy had an extended trench dug 6' into the ground (or some depth well-below his frost line), and made a long duct of large, unglazed clay sewer pipe. One end came up through the floor of the greenhouse, and the other end was enclosed in a structure above ground. The inlet end was covered with a mesh and filter to prevent all but air from entering. A thermostatically-controlled fan in the GH drew air through the submerged pipe, where the natural subsurface temperature was in the low-'60's F year round, which is certainly plenty warm for nighttime, with solar heating boosting the daytime temp. In the summer, he would switch to a cooling thermostat, drawing that same cool air. That's certainly less maintenance than a swamp cooler! The article also discussed how the unglazed clay absorbed the condensed humidity in the summer, and moistened the air in the winter, but I don't recall details. -- Ray Barkalow - First Rays Orchids - www.firstrays.com Plants, Supplies. Books, Artwork, and lots of Free Info! "alpickrel" wrote in message oups.com... You were smart. My old hoophouse frame is still standing right next to the greenhouse. It is 15 x 30 (or so). Just the metal frame right now. It has grapes growing on it. I have had the idea in the back of my head to cover it with insualtion and black plastic water circulating tubes and turn it into a giant solar hot water collector/storage unit of some kind that I can then use at night to pump the heat into the greenhouse next to it. The heat sink can't be IN the greenhouse because to be of any real use, whatever goes in there...a pool or whatever..., it has to be able to get hot enough to be of use long after the sun gets off it, so plants won't be able to be grown in there with it. (now I get K Barrett's joke about lying to herself about her barrel of water.) I was staring at my electrical subpanel for the greenhouse this afternoon and wondering what it would take to run a line large enough to power an electric heater that would make me feel like I was not lying to myself when I plugged it in. I still think a good option is to find a way to drag a big warm blanket over the greenhouse every night. I also wondered when somebody with the know how will get the bright idea of turning clear 6 mil greenhouse plastic film into a giant solar electric collector sheet. I mean I spend all summer trying to REMOVE light and heat. It would be nice to be doing something useful with it. There is talk of a spray-on solar panel. On Nov 9, 8:05 pm, "Pat Brennan" wrote: When I put up my last greenhouse I needed a new power service. I had the power company run an extra 200 amps of service and used it for my backup heating system. The thought that oil now costs the same as that backup system is as you said scary stuff. This greenhouse is one third the size of my others. As we started to get into heating season I was able to empty it and turn it off. As oil continues to rise I am wondering if between the store (which closes at the end of the month) and the little greenhouse if I can close a big greenhouse. And if I do not need the greenhouse, I am also wondering how I turn it into a solar collector. I think I need to do some reading on heat pump and transfer systems and swimming pools. Pat |
BTU's per dollar
My guess would be that the cooler air down in the underground pipes
will not be drawn up into the greenhouse if there is cross venting from inlet to exhaust vents in the greenhouse above that bypasses the pipes unless the pipes have an external inlet. Cool air will settle to the lowest point. A fan to push or pull it through the pipes seems required without this external inlet. The system is analogous to swamp coolers: in order to be effective the air coming in must be forced through the cooling structure; be it damp crushed clay filled pipes buried in the earth or soaked pads in front of an inlet shutter. The trench of crushed clay pipes needs one open end to be on the outside of the greenhouse and one to be on the inside. Actually, I would guess two inlet openings and one exhaust are needed. One inlet is outside the greenhouse to draw in air for cooling as vents at the top of the greenhouse exhaust the hotter air. A second inlet is needed (and the first one closed) when air inside the greenhouse is circulated though the pipes to warm it to the average mean temp during "heating". Imagine a semi-passive cooling system where a fan powered by a solar panel forced air through the cooling pipes. For cooling, you only need the fan to come on when the sun is out anyway. To be ultra effective as a heater makes it bit more complicated. I would need to look into heat exchangers and heat exchange technology because we are talking about a primitive heat pump here. Something is needed to 'concentrate' the BTUs before moving them up into the greenhouse air and releasing them. I can see the idea of a passive system being of help if I imagine that what the ground pipes are doing is drawing the mean average air temperature held constant by the earth at about the 6 foot depth up into the greenhouse. This way you start your base air heating BTU requirements at 55 degrees or so and not at whatever the current air temperature is outside the greenhouse. In addition, heated air naturally rises. What you are doing with the pipes when you heat is to increase the ground's heat radiating surface. Imaging a long or deep cave with a plastic bubble setting on top of the opening that traps the air heated to the underground mean average temperature. In a VERY deep tunnel, would the mean average temperature rising up from the bottom be magma? |
BTU's per dollar
My thought was a recirculating system. Say an inlet at the top of the
greenhouse and an outlet at the bottom of the greenhouse, at opposite ends of the greenhouse. A fan or fans would have to be used to force the air through the duct work. I have a feeling that the amount of underground duct work needed to even make a slight difference will be substantial. It probably would be just as effective if you just sunk the greenhouse into the ground a few feet. "alpickrel" wrote in message ups.com... My guess would be that the cooler air down in the underground pipes will not be drawn up into the greenhouse if there is cross venting from inlet to exhaust vents in the greenhouse above that bypasses the pipes unless the pipes have an external inlet. Cool air will settle to the lowest point. A fan to push or pull it through the pipes seems required without this external inlet. The system is analogous to swamp coolers: in order to be effective the air coming in must be forced through the cooling structure; be it damp crushed clay filled pipes buried in the earth or soaked pads in front of an inlet shutter. The trench of crushed clay pipes needs one open end to be on the outside of the greenhouse and one to be on the inside. Actually, I would guess two inlet openings and one exhaust are needed. One inlet is outside the greenhouse to draw in air for cooling as vents at the top of the greenhouse exhaust the hotter air. A second inlet is needed (and the first one closed) when air inside the greenhouse is circulated though the pipes to warm it to the average mean temp during "heating". Imagine a semi-passive cooling system where a fan powered by a solar panel forced air through the cooling pipes. For cooling, you only need the fan to come on when the sun is out anyway. To be ultra effective as a heater makes it bit more complicated. I would need to look into heat exchangers and heat exchange technology because we are talking about a primitive heat pump here. Something is needed to 'concentrate' the BTUs before moving them up into the greenhouse air and releasing them. I can see the idea of a passive system being of help if I imagine that what the ground pipes are doing is drawing the mean average air temperature held constant by the earth at about the 6 foot depth up into the greenhouse. This way you start your base air heating BTU requirements at 55 degrees or so and not at whatever the current air temperature is outside the greenhouse. In addition, heated air naturally rises. What you are doing with the pipes when you heat is to increase the ground's heat radiating surface. Imaging a long or deep cave with a plastic bubble setting on top of the opening that traps the air heated to the underground mean average temperature. In a VERY deep tunnel, would the mean average temperature rising up from the bottom be magma? |
BTU's per dollar
On Mon, 12 Nov 2007 15:06:41 -0600, "Mark_OK" wrote:
My thought was a recirculating system. Say an inlet at the top of the greenhouse and an outlet at the bottom of the greenhouse, at opposite ends of the greenhouse. A fan or fans would have to be used to force the air through the duct work. I have a feeling that the amount of underground duct work needed to even make a slight difference will be substantial. It probably would be just as effective if you just sunk the greenhouse into the ground a few feet. We sunk the support walls on the lean-to greenhouse - wall is depth of house wall (basement). Filled the gh with cobbles ( football sized rock) then topped with gravel for a level floor. We put pipes in the cobbles - planned to force ceiling height air down thru the pipes and let it drift up thru the cobbles to create humidity. Never did find a way to use a fan to do this. The vertical is now gone and since the gh floor has settled I will bet the pipes collapsed under the cobbles as well. But the 4 foot of rock in the gh floor is a mitigating factor on heat and cold. I thought the article was clay pipe with the clay walls pulling humidity from the surrounding ground water and would need a reversible fan to force hot air in to cool and pull warmed air out to mitigate the cold. If a loop maybe the fan only goes one way and the effect is different by the season. SuE http://orchids.legolas.org/gallery/main.php |
BTU's per dollar
It was more me trying to save a penny than being smart. I was installing a
heat pump for summer phal forcing. The unit came with resistive backup and it made no difference if the power company installed a 200 or 400 amp drop. It was basically a free backup system that I knew I could not afford to run very long. We hooted and howled as we watched the meter spin when I first tested the unit. The fact that oil is now making the meter spin as fast has yet to make me hoot or howl, more like moan and groan. I feel pretty silly that my only heat pump is attack to a greenhouse not currently being heated. I am thinking more and more that I will change that after our annual sale this weekend. Of all my heating options short of burning wood or coal, I think heat pumps are my best option. I just have to figure out how to use solar to my best advantage and come up with an efficient way to store and retrieve heat. I think it is doable and the retrofit costs would not be that great. But with the way the orchid economy is right now I am just not sure it is worth the effort and money. I am afraid that doing nothing may just be conceding defeat. Al, I too have been thinking about greenhouse blankets for a while now. I have done net searches looking for the perfect blanket and have not had much luck. Pool covers and greenhouse thermal curtain are not right. I did find a space blanket type material. It would stop IR loss but would add no R value. We need big bolts of the material they make gloves out of, something like Dupont's thinsolate. Pat "alpickrel" wrote in message oups.com... You were smart. My old hoophouse frame is still standing right next to the greenhouse. It is 15 x 30 (or so). Just the metal frame right now. It has grapes growing on it. I have had the idea in the back of my head to cover it with insualtion and black plastic water circulating tubes and turn it into a giant solar hot water collector/storage unit of some kind that I can then use at night to pump the heat into the greenhouse next to it. The heat sink can't be IN the greenhouse because to be of any real use, whatever goes in there...a pool or whatever..., it has to be able to get hot enough to be of use long after the sun gets off it, so plants won't be able to be grown in there with it. (now I get K Barrett's joke about lying to herself about her barrel of water.) I was staring at my electrical subpanel for the greenhouse this afternoon and wondering what it would take to run a line large enough to power an electric heater that would make me feel like I was not lying to myself when I plugged it in. I still think a good option is to find a way to drag a big warm blanket over the greenhouse every night. I also wondered when somebody with the know how will get the bright idea of turning clear 6 mil greenhouse plastic film into a giant solar electric collector sheet. I mean I spend all summer trying to REMOVE light and heat. It would be nice to be doing something useful with it. There is talk of a spray-on solar panel. |
BTU's per dollar
On Nov 13, 8:33 am, "Pat Brennan" wrote:
It was more me trying to save a penny than being smart. I was installing a heat pump for summer phal forcing. The unit came with resistive backup and it made no difference if the power company installed a 200 or 400 amp drop. It was basically a free backup system that I knew I could not afford to run very long. We hooted and howled as we watched the meter spin when I first Today I am working in the greenhouse and contemplating the frightening oil bill I just got. I thought oil was $2.799 per gallon. But that's the home heating oil price. I would have paid sales tax of 5% on that making it $2.93 per gallon, but last year I learned that as a business I can send the oil vendor a signed certificate to allow me to not be taxed since the fuel is used to produce items for resale. This woke them up to the fact that I am a business and should not be paying "home" heating oil prices. I am now paying "Fuel; commercial tax discount" prices of $3.094 per gallon. (NO tax on that, however) You just can't win. Buying oil sans sales tax will now cost me almost $500 more per season. It never dawned on me to ask if there was a separate pricing structure before I sent the tax form in. I should have known. I looked into electricity prices and learned that as long as Dominion power assumes I am using all this electricity for home use it is less expensive than what businesses pay. So I should not have been caught by surprise here. (Electricty is looking prettier all the time. Of course, if I run a bigger electric line in to power an electric heater for my "commercial" greenhouse, somebody at the electric company will notice.) |
BTU's per dollar
Around here oil price drops with volume no matter what you use it for. It
sounds like you need to put your oil business out for bid. I am able to get quotes as margins so at least I can compare fruit with fruit. In some areas you can get a quote in $/gal for the whole season, no one has ever offered me a lock in price. Expect to save 2 to 20 cents off the 'home' prices. Around here 'home' electric service is at most one 400 amp drop. Pat |
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