Dumb heating element and water pump
- Thread starter fatjay
- Start date
I see where you are going, I will tell you about the two folk I know with the systems. Now I don't know their bills, or time to get "warm" but I do know a little bit about two systems on each end of the extreme.
Guy one lives in northern ID almost Canada. His system in in a VERY nice hanger, like airplane hanger. This guy has all kind of cool toys, those $40 four person side by side hot rods, naturally airplanes. I think he lights cigars with $100 bills. His system in commercial, and only has it off for a few months in the spring-fall. When outside temps are in the 50's it is getting cold at night. His runs all the time, and the floor is "warm" to the touch. It is not "hot", and warm is not the best word. Lets say you put your hand on the wood kitchen table in your house, thats it.
The other guy is a "home made" setup using a big hot water heater. I think he said he has 3-4 different "loops", not sure if that is a thing, I really don't know much about it.
When he cranks his up again around this time of year here in middle MO. He has it set to pretty hot. You don't want to hold your hand under the water hot. he says that will warm up the slab quicker. I never asked how quick. Then he will turn it down to what I would call lukewarm. Personally I think the floor is still cool to the touch, much cooler then guy 1, but it is warmer then my floor, when on a 50f day and you open the shop it is flat cold in there, and if you leave a bottle of water on the floor it is the same temp as you take it out of the fridge. His is on 24x7 in the winter. Everything he has is electric. I don't know what the bill did after he hooked that up, that would be tacky to ask. You don't ask if bills go up, but you do ask if bills go down....solar people tend to like to talk about that.
I think it would have to, I have never seen the light on the water heater off, but I don't look every time I am over there. And that pump is always running, you can hear that in one part of his shop. He is a big time wood worker with vac hoses in the floor and this big fancy dust collection deal he setup. Stuff to keep the wood in storage nice, humidity,heat, cool all that jazz.
I also admit I am not sold on it for my use. I am out in my shop darn near every day, at least 4 hours after work, and usually most weekends. It is my man cave. I just have normal heat. Up stairs it gets quite warm with the heat running that you need to turn it off even with two fans moving stuff around. I thought about heating the slab, but not sure if my use would warrant it.
Peco is the power company.
Yes, it's a 50/50 mix with water and RV anti-freeze, water is just a bit of an oversimplification.
I heat my house with wood. It's a bit of a pain. Felling tree's, cutting them up, splitting the wood, seasoning the wood. I'm looking for less maintenance and less reliance on outside elements.
I know a guy in nebraska that heats his shop with radiant floor heat with electric hot water for between $40-60/mo. However, he has massive amounts of insulation. Which I will have eventually. But not yet. My walls are 8" thick which means I can get R27 in there, and R40-50 in the roof. The garage doors and man doors are insulated as well. The idea is once there's heat there, it'll stay.
Yes, it's a 50/50 mix with water and RV anti-freeze, water is just a bit of an oversimplification.
I heat my house with wood. It's a bit of a pain. Felling tree's, cutting them up, splitting the wood, seasoning the wood. I'm looking for less maintenance and less reliance on outside elements.
I know a guy in nebraska that heats his shop with radiant floor heat with electric hot water for between $40-60/mo. However, he has massive amounts of insulation. Which I will have eventually. But not yet. My walls are 8" thick which means I can get R27 in there, and R40-50 in the roof. The garage doors and man doors are insulated as well. The idea is once there's heat there, it'll stay.
orangezero
New Member
- Joined
- Sep 20, 2020
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One idea that isn't mentioned much is to hook up solar panels outside and wire them up to solar panels inside. Panels are basically just large surface area diodes that can dissipate heat, and you can more easily keep them near the max power point of the outside panel and get a bit more energy than just directly hooking up a heating element to a solar panel. You could also use diodes in series to dissipate heat, but you already have panels.
The guy I heard about this from used two outdoor panels to run into 2/3rds of an indoor panel, and it heats his internal panel up to a good temp, but less than a typical solar panel may get on a hot roof in summer. Dacian from electrodacus.com has pictures on his forum/website in the gmail section. Not everyone wants solar panels in their homes, but for this case it could do some good without spending a lot of money.
The guy I heard about this from used two outdoor panels to run into 2/3rds of an indoor panel, and it heats his internal panel up to a good temp, but less than a typical solar panel may get on a hot roof in summer. Dacian from electrodacus.com has pictures on his forum/website in the gmail section. Not everyone wants solar panels in their homes, but for this case it could do some good without spending a lot of money.
ruralsolar
New Member
Lots of math about how much energy to heat the slab to a certain temp. What is really missing to help size the system is the temp the slab needs to be at to keep the air temp at a certain point (if that is something desired beyond warming up the floor some for when doing work). Siegenthaler has some excellent webinars and blogs about low temp hydronics, more specifically in this case, the math to figure out what surface temp a floor needs to be at to maintain a certain room temp assuming you know the BTU load of the space.
www.pmmag.com
John Siegenthaler: Radiant panel systems
Radiant floors don’t necessarily have to feel warm to work properly.
www.pmmag.com
They offer residential heating TOU rates. Try their cost savings estimate: https://www.peco.com/smart-energy/innovation-technology/time-of-use-pricing
That is interesting, I didn't know that existed. Thanks.
Whats-n-Watts
New Member
Water Heating Calculator for Time, Energy, and Power
The calculators on this page compute how long it takes to heat water, how much energy is consumed, and how much heating power is required.
DC submersible water heater element for 12 24 and 48 volt heating
DC submersible water heater elements for 12 24 and 48 volt heating. a great alternative to AC and sumplimenting solar hot water systems
www.hurricanewindpower.com
A 4500w 240v element can be used but a true DC would perform much better. 240v will only give you around 900w or so water heating power at 48v. I read something to the effect of each time the ac element voltage is reduced by half the output is 25% of the sticker ratings or something like that. Unless you use an inverter stick to the DC element. Missouri Wind and Solar have the reputation of selling AC elements for DC but I have no experience with them so I can't say for sure.
You could throw a small battery in, wire as a normal small system and just leave the inverter out if the mix. You could power one off the battery and the top element off the LVD. A decent scc should supply the rated Amps of the controller. I'm going to do some experiments with a dump load fed into a MPPT battery input so the controller has voltage to power it from a separate system and throw a panel or two on the second scc and set them so that when the LVD from controller #1 drops off the other #2 still has power coming in. Of course I will fuse and diode between the two controllers to prevent back feeding. Will it work? I don't know but there is one way to find out. Try it.
Quattrohead
Solar Wizard
I'm going to suggest you ditch the radiant heating entirely and use mini splits instead. They are mega efficient and quite simple to get up and running on solar.
But first of all, insulate the building. It's not fun or sexy but it is by far your best investment.
But first of all, insulate the building. It's not fun or sexy but it is by far your best investment.
Zwy
Solar Wizard
Entirely off mini splits probably works in FL, not so good here.
The trend I see now is air to water heat pumps and this is used for radiant heating. This is done with thermal storage and if you look at John Siegenthaler's training material, it shows this is the trend. I run radiant floor heat in my shop using a condensing boiler. The system has worked great for about 12 years now. I'm heating 4400 sq feet with 18 foot ceiling with about 900 gallons all season with shop temp at 70F.
But back to the thermal storage. The heat source can be multiple sources, direct electric, gas condensing boiler, oil boiler, biomass and ground source or air to water heat pump. I'm currently in planning and acquisition stage of a project to heat my house. Tomorrow I will be picking up a pair of 525 gallon boiler tanks for thermal storage. I can use these in conjunction with any of the heat sources listed above.
I built this system about 8 years ago. It is closed loop, the source is a 75 gallon propane water heater which also provides domestic HW.
It is heating a 6" slab in a 1200 sf attached garage which is insulated. Nothing fancy with insulation, just 6" walls with batting, R38 (I believe) in the ceiling. Floor has 1 1/2" foam board under and 3" around sides/edges. I am located in the inland NW, so pretty cold temps in winter (-20 is not unusual).
I set it at 62 when I know I'm going to be working on projects for several days or weeks and back it down to 55 if I don't plan on being out there much. Floor heats up at about 1 degree per hour. It's not to bad to run like this (cost wise) but if I run it up to 70F or higher it goes through the propane rapidly. Running it the way I do (55 - 62) I use about 1000 gallons of propane a year. I love this system and it has worked flawlessly. I have always thought it would be really cool to have an alternative source of heat for my system such as PV or even better have PV as the primary source and propane as backup. I am very interested to see what you come up with. Please keep us posted with your progress. That is a beautiful shop you are building.
It is heating a 6" slab in a 1200 sf attached garage which is insulated. Nothing fancy with insulation, just 6" walls with batting, R38 (I believe) in the ceiling. Floor has 1 1/2" foam board under and 3" around sides/edges. I am located in the inland NW, so pretty cold temps in winter (-20 is not unusual).
I set it at 62 when I know I'm going to be working on projects for several days or weeks and back it down to 55 if I don't plan on being out there much. Floor heats up at about 1 degree per hour. It's not to bad to run like this (cost wise) but if I run it up to 70F or higher it goes through the propane rapidly. Running it the way I do (55 - 62) I use about 1000 gallons of propane a year. I love this system and it has worked flawlessly. I have always thought it would be really cool to have an alternative source of heat for my system such as PV or even better have PV as the primary source and propane as backup. I am very interested to see what you come up with. Please keep us posted with your progress. That is a beautiful shop you are building.
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Daddy Tanuki
Solar Wizard
maybe a stupid question, but why not build a cheap water boiler using firewood for the duration? you live in Penn... plenty of wood to burn especially since this is not a fireplace or wood stove where you need to worry about creosote buildup. a tank that you can build a fire around and a pump...
then when you have the time/cash/whatever you can convert to whatever your original plan was
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