Jager February 14, 2011 Share February 14, 2011 Wow, I just read that, I guess I wasn't terribly coherent after 20 hours at work!! Dave, theoretically the input could be applied anywhere in the system to achieve oscillation at the system's natural frequency. The more I think about it the more that I think it would work to have a single cylinder. The key is going to be having enough variability in the design to vary the frequency and the magnitude of the piston. Frequency is easily accomplished by having a variable speed motor driving the piston. Magnitude will be a little more difficult to change since it will be changed by "hard set" physical features of the device such as stroke length and cylinder diameter. just a thought, but depending on the size of the drive "wheel" attached to the motor fine tuning the initial model could be a simple as cutting the piston arm mating area with a channel with teeth in it instead of just one hole for a screw or bolt. then you simply move the arm in or out the diameter of the drive wheel and tighten down into one of the teeth to lock it into place as you test. you could forgo the teeth and simply clamp the arm in with a very tight bolt, but the teeth should allow better grip and less chance of the arm sliding out of the intended spot. it is a design that i have heard steam engine modelers and builders used to find the proper settings for their piston travel. HTH Link to comment Share on other sites More sharing options...
dave w February 14, 2011 Author Share February 14, 2011 just a thought, but depending on the size of the drive "wheel" attached to the motor fine tuning the initial model could be a simple as cutting the piston arm mating area with a channel with teeth in it instead of just one hole for a screw or bolt. then you simply move the arm in or out the diameter of the drive wheel and tighten down into one of the teeth to lock it into place as you test. you could forgo the teeth and simply clamp the arm in with a very tight bolt, but the teeth should allow better grip and less chance of the arm sliding out of the intended spot. it is a design that i have heard steam engine modelers and builders used to find the proper settings for their piston travel. HTH I think I understand what you mean by this. Now that I've moved the refugium away from the surface of the tank I will need another cylinder to create waves in this area, otherwise the algae growth tends to look stagnant. This refugium is above the tank water line and the two motors don't need to be timed. Happy Valentines Day to all, we take care of our wives so they let us enjoy reef tanks. Link to comment Share on other sites More sharing options...
dave w February 14, 2011 Author Share February 14, 2011 use pvc as the skeleton of the cement rock. It'll make it lighter, plus you can run water thru it. This is a good point if I don't cast the whole thing in a snow mold. If I used something substantial like 2" PVC, I could place it horizontally and turn it to add the artificial live rock mix. That mix of cement/sand/crushed oyster shells/rock salt is pretty weak and doesn't bond well unless it is put on a horizontal surface. I'd have to keep turning the "tree" to keep adding the cement mix to it. Link to comment Share on other sites More sharing options...
zygote2k February 14, 2011 Share February 14, 2011 no more snow. make a pvc "tree" and place it in a sand mold, fill with aragocrete, cure it, run it. it'll be fine. Link to comment Share on other sites More sharing options...
Chad February 15, 2011 Share February 15, 2011 OK, Dave, I have an initial guess that I calculated (based on a few assumptions) and validated from the info that DaveLin gave me in another thread. I think the device should displace between displace between 10-18 gallons (I expect 14 gallons to be an ~1" wave) with a frequency of ~ 3 seconds (though I calculated a 30% error on this, so it could be anywhere between 2.2 - 4.0 seconds or so). I would choose a cylinder with a diameter of 8" and stroke length that can be varied from ~4-12". (basically a 13-14" diameter gear to drive the piston). Good place to start? Link to comment Share on other sites More sharing options...
zygote2k February 15, 2011 Share February 15, 2011 If you make your piston device like an engine, you could place it under water and on the downstroke, it will pull water from one side and on the upstroke, it wil push water out the other side. If you make a camshaft then you can make an oscillating wave with two of the pistons. Link to comment Share on other sites More sharing options...
Chad February 15, 2011 Share February 15, 2011 If you make your piston device like an engine, you could place it under water and on the downstroke, it will pull water from one side and on the upstroke, it wil push water out the other side. Exactly. If you make a camshaft then you can make an oscillating wave with two of the pistons. true, but probably an unnecessary complication to the design since a single piston will do the job if sized properly (for the "oscillating" wave you are referring to, a single piston at double the frequency will do the same thing. Link to comment Share on other sites More sharing options...
davelin315 February 15, 2011 Share February 15, 2011 Dave, I don't know how much temperature will be an issue. I thought that it would become an issue in an outdoor pond I had last summer to house school stuff, but the only issue that eventually came up was when it was cold for several nights and days in a row. Prior to that I had a 300 gallon rubbermaid tub sitting on pavers under my deck. It received afternoon/evening sun for about 3-4 hours and the temperature never got hot throughout the entire summer and there was very little fluctuation, despite the fact that the air temp would climb into the hundreds and the tub is black. With your sumps being in the ground, I think that the ground temperature will regulate the water for you, with your need being heating rather than cooling. Link to comment Share on other sites More sharing options...
Jager February 15, 2011 Share February 15, 2011 following dave there, you may wish to temporarily fill a refugium section with water and put a temperature probe in to monitor where the water evens out to then possibly check it morning noon or night (if you have a controller use the datalogging and save your sanity) I have a feelign based on how you have set up the tanks that you may see water that is a bit cooler then expected (mid 70's or so maybe less) and you may see higher expense to heat the water up to your wanted amount. If that is the case while it is still uncovered and such you could insulate the tanks on the earth sides and cinderblock sides and leave the viewing side open still, which should use less energy overall once your water reaches desired temp. HTH Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 Dave, I don't know how much temperature will be an issue. I thought that it would become an issue in an outdoor pond I had last summer to house school stuff, but the only issue that eventually came up was when it was cold for several nights and days in a row. Prior to that I had a 300 gallon rubbermaid tub sitting on pavers under my deck. It received afternoon/evening sun for about 3-4 hours and the temperature never got hot throughout the entire summer and there was very little fluctuation, despite the fact that the air temp would climb into the hundreds and the tub is black. With your sumps being in the ground, I think that the ground temperature will regulate the water for you, with your need being heating rather than cooling. It will take at least a year for the bulb of temperature to build up around the tank and I'd guess this steady temperature will be 70 or so. So I agree that winter heating may be more of a problem than summer cooling. I don't see summer temps as much of a problem. If I need to raise the tank temp I can just use a large blower and put a lot of hot air in the water. I worry about August when it is 95 to 100F outside and we're near 100% humidity. In winter, keep in mind that the earth is a good insulating blanket and that the greenhouse has a relatively small amount of exposed surface area. I plan to run underground pipes through the back yard for geothermal. This built up heat will help warm the tank during the winter, but by February or March all that built up heat may be used up and I need extra heating. Time will tell, but I think you will be right about a winter heating deficiency. Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 following dave there, you may wish to temporarily fill a refugium section with water and put a temperature probe in to monitor where the water evens out to then possibly check it morning noon or night (if you have a controller use the datalogging and save your sanity) I have a feelign based on how you have set up the tanks that you may see water that is a bit cooler then expected (mid 70's or so maybe less) and you may see higher expense to heat the water up to your wanted amount. If that is the case while it is still uncovered and such you could insulate the tanks on the earth sides and cinderblock sides and leave the viewing side open still, which should use less energy overall once your water reaches desired temp. HTH Good points. I have 4" of insulation around the three underground walls and the 16' high fourth side is against the warm wall of the basement and the house. Insulation simply slows heat transfer, it doesn't stop anything. Even this much insulation is only effective about 3' deep into the soil, after that the ground temperature tends to be an unchanging 55F to 60F. I suspect you and Dave will be right that my stable temperature will be on the low side. But unless you have a better idea, I'd guess the first year of sump water temp measurements may not tell me much because it could take that long to stabilize the temperature of the surrounding ground. I got three 100' coils of 4" pipe today to bury around the underground cinderblock walls. If I leave off a summer shade cloth, the room could easily go over 100F much of the summer with 400 square feet of glass facing due south. If I run an air blower through these cool pipes it may build up enough "heat sink" in the surrounding ground to last much of the winter. But my gut feeling is that you and Dave are right, halfway through the winter I will probably need supplemental heat as the stored heat flows from the outside ground into the room and then out through the glass covering to the cold winter. There is a guy with a greenhouse in northern Ohio on RC who put a layer of 8mm twinwall polycarbonate on both sides of his walls. Although each glazing is only R-1.5 or so, the 8" thick "air sandwich" in between may bring the R value up to R-8 or higher. I asked if this would reduce too much light transmission and they politely laughed and said that too much light will be my problem, not too little. So my point is that I could create thick insulation with a second layer of glazing for about $1,000 and in the long run this will probably be cheaper than winter heating bills. I should probably make this decision before the 2012 winter. Keep up the critique. Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 Exactly. true, but probably an unnecessary complication to the design since a single piston will do the job if sized properly (for the "oscillating" wave you are referring to, a single piston at double the frequency will do the same thing. Rob and Chad, are you guys saying that the piston should move side to side instead of up and down? Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 (edited) OK, Dave, I have an initial guess that I calculated (based on a few assumptions) and validated from the info that DaveLin gave me in another thread. I think the device should displace between displace between 10-18 gallons (I expect 14 gallons to be an ~1" wave) with a frequency of ~ 3 seconds (though I calculated a 30% error on this, so it could be anywhere between 2.2 - 4.0 seconds or so). I would choose a cylinder with a diameter of 8" and stroke length that can be varied from ~4-12". (basically a 13-14" diameter gear to drive the piston). Good place to start? This is a perfect place to start, I will make a piston and cylinder as soon as the frame is welded and the tank fiberglassed. I don't see this taking much time so it will be easy to scrap or modify if we find it's not working well enough. Thanks for your best guess at the size. Edited February 16, 2011 by dave w Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 no more snow. make a pvc "tree" and place it in a sand mold, fill with aragocrete, cure it, run it. it'll be fine. I will do it as soon as the tank is fiberglassed. Right now it appears that our snows are over for a while. Link to comment Share on other sites More sharing options...
Jager February 16, 2011 Share February 16, 2011 i would look at at doing what you posted with the insulation, then air pocket then insulation and refugium tank probably dave, I don't know how comfortable you are with that or if it is feasible given the weight and materials you are using, but much like a double or triple insulated window you want to be able to control influx and outflow of heat as much as possible. This may result in you using your ground loop for cooling more, but i am very concerned about the winter weather in DC and ground temps. you may end up spending inordinate amounts of energy to heat the tanks due to ground leeching heat away from the tanks. maybe build and insulate the refugium tanks with multiple layers per side by sandwiching insulation or spraying foam insulation in between the pieces to lessen heat loss. better to test this sorta thing now while the ground is still chilly and see what happens. HTH Link to comment Share on other sites More sharing options...
Chad February 16, 2011 Share February 16, 2011 Up and down since it will be easiest to implement and the travel will be less (not sure if I misunderstood what Rob was saying or not, I thought he was talking about using both sides of the piston for a push-pull effect). You have most of the parts for a heat pump (heat sink, heat source, pump, and tubing between them... all you need is a condensor), perhaps you could incorporate one for your heating and cooling? I have a book on the subject if you want to take a look at it. I picked it up after being intrigued at feeling a warm pipe that was being heated by the frozen ground during winter in upstate NY. Link to comment Share on other sites More sharing options...
LanglandJoshua February 16, 2011 Share February 16, 2011 (edited) I think your talking about geothermal heating/cooling Chad, its amazing what nature already does for us. Yet with all our advanced systems it can be a pain to take advantage of it. Edited February 16, 2011 by LanglandJoshua Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 i would look at at doing what you posted with the insulation, then air pocket then insulation and refugium tank probably dave, I don't know how comfortable you are with that or if it is feasible given the weight and materials you are using, but much like a double or triple insulated window you want to be able to control influx and outflow of heat as much as possible. This may result in you using your ground loop for cooling more, but i am very concerned about the winter weather in DC and ground temps. you may end up spending inordinate amounts of energy to heat the tanks due to ground leeching heat away from the tanks. maybe build and insulate the refugium tanks with multiple layers per side by sandwiching insulation or spraying foam insulation in between the pieces to lessen heat loss. better to test this sorta thing now while the ground is still chilly and see what happens. HTH The 8mm twinwall polycarbonate is light, a 64 sq. ft. (4' by 16') panel only seems to weigh 35 pounds or so. A second layer inside the room should not be too hard to install. Rather than insulate each sump seperately I will insulate the whole underground portion of the room around its perimeter, so all 2,000 gallons of sump will be the same temperature as the ground. If the room hits 90F in the summer and 70F in winter, the ground temp may vary between 80F in summer and 65F in winter, as a guess. I think the trick is to use an underground water circulation system in the summer to build up as much heat in the ground as possible. I like the idea of drawing my summer air through soil tubes because that also helps warm up the soil all around the room. As you can see from the pictures, the room is about 7' below ground level. I think we all agree that summer cooling will not be as critical as winter heating. I once put in a geothermal heating system and 8 tons of heating required about two thousand feet of underground pipe, as I remember. I guess that this 400 square foot room may require half a ton of heating and cooling if it is well insulated and much of this load will be taken care of by my extension of the house HVAC plenum (forced air) system to the sunroom. Although half a ton may be ample, it never hurts to have extra cooling and heating capacity for extreme weather. If I run 2" PVC pipes about 36" underground for a couple hundred feet I think I may approach half a ton of winter heating capacity, although come March I may regret that I didn't put in more. I guess I'm talking myself into another 100' of geothermal piping, it is pretty cheap to install. I hope the sunroom has low heat gain and loss. It is basically a hole in the ground with a glass cover. The north wall is normally the biggest heat loser but this 17' x 20' wall is shared with the house so it has no heat gain or loss. Other than the south facing glass roof, the only other exposed wall is the west one to let in afternoon sun and this small wall is only 140 sq. ft. The proof will be shown in my August and March water temperatures, when I will see if heating and cooling needs are larger than I anticipated. Link to comment Share on other sites More sharing options...
dave w February 16, 2011 Author Share February 16, 2011 Up and down since it will be easiest to implement and the travel will be less (not sure if I misunderstood what Rob was saying or not, I thought he was talking about using both sides of the piston for a push-pull effect). You have most of the parts for a heat pump (heat sink, heat source, pump, and tubing between them... all you need is a condensor), perhaps you could incorporate one for your heating and cooling? I have a book on the subject if you want to take a look at it. I picked it up after being intrigued at feeling a warm pipe that was being heated by the frozen ground during winter in upstate NY. I have a left over 3 ton condensor from a failed geothermal project. It is larger than I need but may still do the trick. It exchanges heat from ground water to freon then compresses the freon like a normal heat pump. Link to comment Share on other sites More sharing options...
Jager February 16, 2011 Share February 16, 2011 i would assume you are correct dave, I cannot find the link or article, but there was a tpye of glass coating that allowed light through on one side but trapped its escape back out, it was used in high tech greenhouses years ago to help prevent winter temperature drops, I will continue to google search in hopes that i can find it, but what you are looking at insulation and geothermal wise should be ok unless my math is terrible again. i reread what you posted above about forced air usage if the temp drops instead of using drop in heaters, i think depending on how you have sealed the greenhouse/ refugium areas, to be the most efficient way of heating the water economically, but you also mentioned on page 1 radiant heating, have you considered tiling the floor under the entire tanks and running a radiant heat system that is separate from the room radiant heat connected to a thermometer or tank controller? that way the heat naturally rises through from the tiles to the tanks (abet that glass or acrylic tanks arent the best heat absorbers,) so you minimize the flow needed to keep the water uniformly warm? once the tank hits a certain temp the radiant heat is shut off by the controller. whether that is worth doing or not I do not know, but it would make it a lot more pleasant to be in the room in the winter due to a nice warm floor. Link to comment Share on other sites More sharing options...
steveoutlaw February 16, 2011 Share February 16, 2011 Pictures!!! Link to comment Share on other sites More sharing options...
dave w February 17, 2011 Author Share February 17, 2011 i would assume you are correct dave, I cannot find the link or article, but there was a tpye of glass coating that allowed light through on one side but trapped its escape back out, it was used in high tech greenhouses years ago to help prevent winter temperature drops, I will continue to google search in hopes that i can find it, but what you are looking at insulation and geothermal wise should be ok unless my math is terrible again. i reread what you posted above about forced air usage if the temp drops instead of using drop in heaters, i think depending on how you have sealed the greenhouse/ refugium areas, to be the most efficient way of heating the water economically, but you also mentioned on page 1 radiant heating, have you considered tiling the floor under the entire tanks and running a radiant heat system that is separate from the room radiant heat connected to a thermometer or tank controller? that way the heat naturally rises through from the tiles to the tanks (abet that glass or acrylic tanks arent the best heat absorbers,) so you minimize the flow needed to keep the water uniformly warm? once the tank hits a certain temp the radiant heat is shut off by the controller. whether that is worth doing or not I do not know, but it would make it a lot more pleasant to be in the room in the winter due to a nice warm floor. Every September for the past 5 years I have sworn that I would build a solar water collector on my roof before winter. This would dovetail nicely with radiant heat but some other project always gets in the way (kids, job, etc.) I will plumb radiant heating lines under the floor and under the tank. I don't worry much about what the lines contact as long as they are under the main display tank. The floor will be 18" travertine squares over plywood. Travertine is a type of limestone/marble, soft and easy to cut. This is good, because I am placing a floor drain in the center of the sunroom so I can wash the room with a garden hose and handle inevitable water spills. Putting flat squares on a conical floor doesn't work so I will have to trim each square into a wedge for even grout joints. Friends say not to worry, nobody will ever look at the floor while surrounded by 40 some feet of reef tank. So plumbing pex tubing for radiant heat is easy, building the solar collector and wood boiler combination to power the system is hard. At least I will have a new project to keep me busy when the tank is done. My experience on energy use tells me to keep multiple options. I will route the house HVAC plenum to the sunroom, install a generator, geothermal lines, pull in a gas heater (my house is on a gas line), and one day use the solar collector and wood boiler to supplement. It may also help to wire up outlets for traditional electric water heating. If a hard winter storm or August hurricane knocks out my power for 2 weeks, all the redundancy will have cost less than 3,000 gallons of dead reef. Link to comment Share on other sites More sharing options...
dave w February 17, 2011 Author Share February 17, 2011 Pictures!!! Steve, my deepest apologies for being a technical idiot. I have pics on my blackberry and a new room layout on sketchup but don't know how to get them loaded into this forum. And this is after it has already been explained to me in writing! I will figure it out soon and post. Link to comment Share on other sites More sharing options...
Jager February 17, 2011 Share February 17, 2011 i finished reading a thread oer at Rc about a 1000g plywood tankbuild and I found the radiant heat "system" I was trying to find for you on top of the floor. here is a direct link to the thread, He ran pex tubing from his water heater through a hot water house pump controlled by a ranco heat controller and 100feet of pex tubing in his sump (separate systems so no contaminating the SW or house water) seems to keep his tank right where he wants it for very low cost. he was seeing less then 15 bucks for 1500gallons of water ish total to heat. Pex radiant heat run page 20 has more photos of the pump etc that may be of help then something else that may save you innumerable headaches a DIY salt mix he used as well. seems his corals and inverts are doing as well or better then previous with RC/IO mixes DIY salt mix it is a bit to read but he has it in grams per 1000gallons, a bit later he breaks down what brand names he used to get the ingredients, and a math formula for mixing smaller amounts with proper ratios. bit of a read but HTH Link to comment Share on other sites More sharing options...
Jager February 17, 2011 Share February 17, 2011 (edited) since I cant edit the last post dave you may wish to look into one of these things, apparently they do all sorts of water movement and do so with minimum electricity usage ie use solar to drive it, its like plug and play for a greehouse granted I have no idea its cost, but it is cool. http://www.oloid.ch/frame.php3?lang=en&nav=pro&content=oloid_typ200 Edited February 17, 2011 by Jager Link to comment Share on other sites More sharing options...
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