Trying to design a super efficiant heater

[Sceadwian]

Heat pumps seem to be a heated issue here =) There's another thread where a fight very similar to this one broke out. That one was a little more complex though because depending on the average ground temperature a few feet underground these systems can generate 4kw's of heating/cooling power using only 1kw of power. The extra energy just comes from the ground and it's tendancy to reach thermal equalibrium. System efficiency depends a lot on soil and local geography as well. Also your latitude makes a big difference, at the equator it's pretty pointless, much the same further north, but in the middle the system are quiet popular now for new installations, mainly because it requires running a lot of water pipes under a pretty large area of ground.

 

[cbiblis]

Yes, you must be speaking of the geothermal hvac systems. I have had my hvac sub's install these systems here in NC per customer request. They are efficient however when weighed out, the installation cost will take over 20 years to compensate for the expenses for the system. Like most solar/geothermal systems. However, the one system that is outstanding in price/savings is a solar hot water heater. These are well worth installing. Everything else is a waste of money at this time.

 

[Sceadwian]

20 years? That's pretty bad, I think a lot of that comes from absurd markups from installers milking people that are willing to go for efficient systems that don't considering the total cost of ownership. I honestly didn't realize they were that bad. If I were ever to do anything like that it would have to be home brewed.

 

[cbiblis]

you think 20 years is bad? Check this out...
So i decided to get into solar energy about 4 years ago. I did alot of research on it and pricing. I priced out the solar kilowatt/power pricing and came up with, If the solar panel where to generate the amount of power that they proclaimed they would generate it would take 30 years to pay off, they are warrantied for 15 not a smart investment. So i decided to try to build my own to save money. I was handy with a soldering iron so i ordered 500 cells for less than 2 dollars a piece(out of china, which was a fraction of the cost to purchase the same rebuilt panels complete.) I did everything myself, cased it in Plexiglas and filled it with nitrogen to keep from fogging. When i completed the project. i ran it for 6 months tracking the savings over each month. Well on average it would take me 10 years to pay off the material cost of the project not even counting the solar tracker that i installed to maximize the yield of production of energy acquired. What a blooming waste of money. I did however build a solar water heater for my 2-1/2 bath house with 4 residents, 3 being girls, and knocked my power bill down a hundred dollars a month. The power company even dropped in on me to see what i had done to drop over 50% of my bill over the past 10 years at that residents. However to be honest i also installed home made attic vents with thermostats to save on cooling cost as well and swapped my light bulbs to fluorescent's, though they only account for 10% of the savings.

Anyhow yes, I agree that the markups are way to high and until people stop buying them at these ridiculous costs, in order to keep up with the Jones's, then the prices will always be out of reach to thoughts who just want to contribute to a better tomorrow.

 

[cbiblis]

by the way the solar hot water heater i designed and built cost me 1200 dollars in material cost. To purchase the comparable system, it would have cost over 8000 dollars to purchase and 6000 dollars to install. Costing a total cost of 14,000 dollars verse my 1200 dollar system with about 30 hrs involved that would be 426 dollars per hour for one man. And that was using a retail supplier, lowe's, for the materials.
Yes, thank god for the internet. There are great links out there on solar water heaters. And it's free. I spent over 100 dollars on the green info sites but i didn't learn a single thing that i hadn't already learned on the forums, bubble gum wrappers and other sites. They're all scams ment to pick your pocket.
Anyhow I'm rambling, I'll shut up now.

 

[tcmtech]

Strange thing how people will spend hundreds of dollars on a fancy chicken hatching machine but wont spend a dime let alone lift a finger to build something that can save them loads of money every day.

At least your doing something and doing it on a level that raises eyebrows!

The world needs far more people doing what you did and letting their friends know how cheap and easy it is to learn to do it themselves as well!

I built a wood burning boiler system 7 years ago for about $3000 and one weeks time invested. To date it has saved me about $17000 in fuel, so I can relate!

 

[cbiblis]

if you were to read the backyard chicken forum that i am on you will notice that i suggest to everyone to build there own incubators from a water cooler, a case fan and a good thermostat, which i offer to sell for 40 dollars on ebay, and a light bulb for a heater. They can build if for 60 bucks, i even give them directions and draw schematics for them. But in the end they want someone else to build it for them. Now i'm being honest when i say that i have 250 dollars in each of the incubators that i build in materials alone. I have 30 hrs in building them. It works out to me making 12 dollars an hour. After shipping and handling cost. This doesn't include my tool maintenance costs such as router & bits, compressor & guns, Saws & saw blades, nor does it include nails, glue, biscuits. Ext. Where the joke is, is the sportsman and the dickey incubators that everyone else buys. They are made from painted 1/2" plywood. Among other things. My quality incubators are 100 dollars less than there cheapest incubators a 5 times better. I'm not trying to make a killing just trying to make a living however i can.

 

[Sceadwian]

Nothing wrong with being made from plywood, it's actually pretty good insulation. Wood is an exceptionally good heat insulator, it's also dirty cheap.

 

[cbiblis]

Maybe in some applications but with incubators there are issues. The r-value is 0.62. solid wood 1.2. We are also dealing with humidity. For 18 days the humidity has to be 50% the last 3-4 days it have to be 80%. Plywood also absorbs bacteria and is hard to clean. Paint wares off and chips. I use wax to seal the cabinets. When there ready to seal i put them in the kiln for an hour then i go into the kiln and rub wax into the wood. When they cool they are moister resistant. I hose mine out after each use with a spray nozzle.

 

[Mr RB]

Do you have any photos? I'd like to see one of your incubators and it might help people suggesting efficiency improvements etc.

 

[dimwatt]

I have been following this thread some. I want to say this about incubators and the backyard chicken hobby. If you search my info, you will see my first post was about chickens.

1st, raising backyard chickens is the fastest growing hobby in the US. In fact , the USA Today even ran an article on raising backyard chickens a couple of weeks ago.

2nd. Large commercial hatcheries have incubating chicks down to a science. Most of the technology really isnt that technical advanced, but priced out of the range of the common hobbiest.

3rd. Hobbest style incubators vary in cost from a $49, styrofoam chest, to a more advance, $4000 plastic oven draw type cabinet that gently rolls the eggs instead of tilts the eggs from side to side. The typical cabinet style incubator that most hobbiest can afford is either the GQF Sportsman, or the Dickey's with a capacity of about 288 eggs. These come at a price of around $600up. If you want to trashtalk Cbiblis's incubators, look up the sportman and dickey incubators first and see just who is trying to take advantage of the eco nutcases.

4th, While it is realitively cheap to build a incubator out of a cardboard box or old cooler, and eggs can be found around the countryside for incubation. Not everybody wants a mutt chicken and they are willing to spend as much as $150 a dozen for some of the more exotic breeds of Birds. $30 a dozen is not uncommon and even the more popular breeds will bring a $1 per egg. Do you really want to trust your $150 investment on a cardboard box or rigged up coleman cooler.

Hatchrates are the name of the game. If you set 12 fertile viable eggs, you expect a 100% hatch rate, if only 2 or 3 hatch in your cardboard box or cooler, you are now up to $50per baby chick in cost. If you hatch 75% in a well build well designed purpose built incubator, you can quickly recover the cost of said incubator just in adverage cost of chicks with every hatch. Two or three poor hatches and you could have paid for a quality incubator. I could go pretty deep in the economics of this situation, but wont. Either do the math yourself or take my word for it, if you are hatching lots of baby chicks, you want/need a quality incubator. It would take $720 worth of $30per doz eggs to fill a 288 cabinet stye incubator to full capacity, a 25% hatch rate would mean only 72 eggs hatch or only about $180 worth of eggs. A loss of $540. This is almost the cost of a well built quality incubator. Do the math on $150 a dozen eggs and see how fast you would go in the hole with a poor hatch rate or how fast a quality incubator could pay for itself.

Offering a well designed and well build incubator at or about the same cost as those currently on the market is not taking advantage of anyone. I also believe a craftmans has the right to recover his or her cost of doing business. If you cant make something for your efforts, then why bother. You electronic guys do charge for your services when a customer calls dont you. Do you feel you are taking advantage of a person just because they dont know how to drawup a PCB or design a circuit.. No you charge them just the same.

I do commend those here at this forum that unselfishly give up their valuable time teaching those that are trying to learn, some of the information found here would be hard to put a price on, how do you sell or price experience.

 

[cbiblis]

Do you have any photos? I'd like to see one of your incubators and it might help people suggesting efficiency improvements etc.

This is the model that i'm working on right know, It's in shambles but you get the jest of it. The heater that is in it is one i built yesterday to try out. It is the 18ohm resistors. It will work good to maintain temp but i'll have to add another nichrome wire to bring the temp up to the temp. The pic of the watt meter is displaying the nichrome heater wattage by itself. This is what i want to change.

 

[cbiblis]

I'm thinking about modifying my thermo design. I was thinking about adding a second relay to the design that will trigger when the temp is 1 degree less then the set temp. This should inturn run the 60ohm nichrome when it's needed and i will use the original relay for the 180ohm resistor heater. Heres the link to the schematic.
https://www.electro-tech-online.com/attachments/hysterisis-png.35634/

R7 is a 10m not a 4.7m

 

[Sceadwian]

Beautiful cabinet. Honestly I wouldn't worry about efficiency for this kind of application. If you want it to be more efficient design it to use better insulation. If it's in a room that would benefit from auxiliary heating just don't bother. One of the best insulators available is air, although you'd have to do a little extra work to cover the cavities to make it pretty looking there's no reason you couldn't use hollow walls with 2 or 3 air layers inbetween, using thinner wood with an air gap rather than a single piece of wood, the R value will jump dramatically.

 

[tcmtech]

Some of the best insulation I have found is the simple double foil backed bubble wrap stuff. Around here the more common brand is Reflectix.

I use it on all of my hot water lines for my boiler and three layers of it, about an inch thick total, is enough to keep snow from melting on 200 F water lines all winter.

Its R value is about 7 per layer but the ability to reflect heat gives it a much higher equivalent R number.

For lower cost high heat retention I dont think there are too many other types that can compete!

 

[Sceadwian]

Foil is a great idea, but you need an air gap to utilize it. In the kind of cabinet cbiblis made the primary conduction method is just that physical conduction, simple air gaps alone will dramatically increase efficiency, add foil to that and it's even better because it reduces the radiation that would be the primary transmitter of heat in an air cavity. Least I think. I'm not entirely sure the primary heat transfer in an air cavity is actually radiation, but it's a greater portion of it compared to simple conduction.

 

[cbiblis]

I will increase the r-value if i have to. I have an idea to do both of the suggestions. I could build the exterior box then line the interior with 1/2" hvac ducting board. Then case it in with a thin 1/4" layer of walnut to cover it up. It would look good and insulate. This would however add a significant amount of cost and time. How about the heater? Are ya'll saying to just install the 60ohm and be done with it?

 

[cbiblis]

my thermostat is still in design state. i have built several prototypes so far. I want to do everything i can to it before i set them in stone and have them printed commercially. Hence the addition of the humidity and temperature leds in the other post i linked to.

 

[Sceadwian]

Yeah, the heating coil is effectively irrelevant as long as it produce enough power to get the temperature you want, just keep in mind if it's capable of producing a too much heat you'll want to add a saftey mechanism seperate from the main system to shut everything down and sound an alarm if it would go over temperature. If it it's well insulated you could start a fire if the temperature controller failed.

 

[cbiblis]

it has a thermocouple on the heater.