How well do solar thermal evacuated tubes work in the winter? Sunmaxx solar

Sunmaxx 30 evacuated tube heat pipe with butler heat dump and butler wand. This system provides about 90% of our hot water needs.
Solar thermal energy (STE) is a technology for harnessing solar energy for thermal energy (heat). Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors. Low-temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for heating water or air for residential and commercial use. High-temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. STE is different from and much more efficient than[1][2][3] photovoltaics, which converts solar energy directly into electricity. While existing generation facilities provide only 600 megawatts of solar thermal power worldwide in October 2009, [note 1] plants for an additional 400 megawatts are under construction and development is underway for concentrated solar power projects totalling 14,000 megawatts.[4]
More energy is contained in higher frequency light based upon the formula of , where h is the Planck constant and is frequency. Metal collectors down convert higher frequency light by producing a series of Compton shifts into an abundance of lower frequency light. Glass or ceramic coatings with high transmission in the visible and UV and effective absorption in the IR (heat blocking) trap metal absorbed low frequency light from radiation loss. Convection insulation prevents mechanical losses transferred through gas. Once collected as heat, thermos containment efficiency improves significantly with increased size. Unlike Photovoltaic technologies that often degrade under concentrated light, Solar Thermal depends upon light concentration that requires a clear sky to reach suitable temperatures.
Heat in a solar thermal system is guided by five basic principles: heat gain; heat transfer; heat storage; heat transport; and heat insulation.[69] Here, heat is the measure of the amount of thermal energy an object contains and is determined by the temperature, mass and specific heat of the object. Solar thermal power plants use heat exchangers that are designed for constant working conditions, to provide heat exchange.
Heat gain is the heat accumulated from the sun in the system. Solar thermal heat is trapped using the greenhouse effect; the greenhouse effect in this case is the ability of a reflective surface to transmit short wave radiation and reflect long wave radiation. Heat and infrared radiation (IR) are produced when short wave radiation light hits the absorber plate, which is then trapped inside the collector. Fluid, usually water, in the absorber tubes collect the trapped heat and transfer it to a heat storage vault.
Heat is transferred either by conduction or convection. When water is heated, kinetic energy is transferred by conduction to water molecules throughout the medium. These molecules spread their thermal energy by conduction and occupy more space than the cold slow moving molecules above them. The distribution of energy from the rising hot water to the sinking cold water contributes to the convection process. Heat is transferred from the absorber plates of the collector in the fluid by conduction. The collector fluid is circulated through the carrier pipes to the heat transfer vault. Inside the vault, heat is transferred throughout the medium through convection.
Heat storage enables solar thermal plants to produce electricity during hours without sunlight. Heat is transferred to a thermal storage medium in an insulated reservoir during hours with sunlight, and is withdrawn for power generation during hours lacking sunlight. Thermal storage mediums will be discussed in a heat storage section. Rate of heat transfer is related to the conductive and convection medium as well as the temperature differences. Bodies with large temperature differences transfer heat faster than bodies with lower temperature differences.
Heat transport refers to the activity in which heat from a solar collector is transported to the heat storage vault. Heat insulation is vital in both heat transport tubing as well as the storage vault. It prevents heat loss, which in turn relates to energy loss, or decrease in the efficiency of the system.

[@popoqwer]

Excellent ... Really well done!

[@beebob1279]

After ten years on the system, how’s it working for you? Did you make changes to anything? Now I see how the on demand hot water will work with this system. I thought by what I’m watching that the water temperature was going to be much higher. Do you have any kind of electrical generation going on also?

[@Manuel-dc7im]

That would be interesting!

[@MB031]

Great video.Well done.I always wanted to know the data up north on Dec.21 solar efficiency.Thank you for sharing this..You have beatifull green house.

[@joecool4656]

I have a correction for the math. He needed to have found the average temperature rise across sensors 2,3 and 4 which comes out to 34.8 degrees. (34.8 degrees) (80 gallons) (8.34 BTU per gallon)= 23.1K BTU. Great Video by the way!

[@adobo6905]

Total of 23.1k BTU day = 6.7 Kw day x $0.13 Kwh taxes included = $ 0.87 day saving . WOW

[@Lou_Zasil]

great vid

[@sailorboy7024]

The temp differential between the collector temp and the water temp is way out of line. 10-30F. is a good amount between the collector and lower tank temperature. That collector requires a flow rate of .80 - 1 GPM for each collector. The flow rate may be set too low. At time stamp 6:25, when looking at the pump station, there is no pressure in the system. All solar thermal systems run better with pressure in the loop. At zero pressure in the line set the expansion tank to the pressure you want in the system, then purge and fill to proper pressure. Also the temp gauges show cooler temps on the hot gauge side than on the cooler temp side returning to the collector. The controller on-off set-point may require some adjusting. Given the 80 gallon storage tank and the single collector, your water temps should finish around 105 - 120F. at that time of the year daily water usage included.

[@jimlahey5354]

Wow way to break it down. Do you work in the industry?

[@NJRESolar]

@Fearlessthinker Actually, the house has a 3 foot overhang, but with the 40 mile an hour winds, it just piled snow everywhere against the back of the house. But a blanket or sheet over the collector, might work.

[@NJRESolar]

system is designed to produce 100% of needs during summer with very little over production, if there is any excess, the top of the collector has a heat dump. If you had a pool or hot tub you could stick the extra heat there.

[@Nicholsp01]

Did you think about mounting the system on the wall of the second floor? It would be out of the way of the shade from the trees and the kids soccer balls. A vertical mount would collect less snow and may result in less excess heat in summer when the sun is higher in the sky.

[@silvercam1]

Very good Video All I'm looking for is a sun tracking computer for my concentrated solar hot water system which will heat my house and hot water needs. Everything else is ready to go, just need to track the sun in Manitoba, Canada

[@rapunzeleh546]

what do you use to insulate the pipes taking hot liquid to the tank? i have copper coming out of the collector which turns to pex as it drops down over the roof... found that copper gets so hot that it actually melted foam insulation sleeves, so was thinking of wrapping in fibreglass, then silver foil bubble wrap painted black... or abs pipe cut in half, then glued back together over the pipes/insulation.

[@marco114]

i'd like to heat my indoor pool this way, live in NC. I wonder how many tubes it would take and if it would warm the water enough to swim in the winter.

[@grahamnumber7123]

Hi do you have some data for cloudy days? I suspect a larger array could compensate but by how much?

[@guilfreehotwater1174]

Thanks! are they still working?

[@BerNieSLU]

Is water circulating between the tank and panel? if so what's preventing it from freezing at night when the pump is offline?

[@jaem355]

You should insulate all your pipes with armor flex 1 inch wall. You could have used a taco 009 and a similar controller I use resolve som 6,7,8.good luck looks great get more collectors and storage..storage is the key to heating with solar.

[@SSingh-nr8qz]

Can you "stack" these solar collectors? As in hook them up in series?

[@alzathoth]

can i use this system for in floor radiant heating too?

[@illuminationclub]

Super...but perhaps a plexiglass cover.....which will keep the unit free of snow

[@tchogworks1987]

What does the pump run off of ? Electric? Our water tank is set on 120 degrees which doesn’t seem that hot sometimes. It appears your taking a lukewarm shower all the time unless it’s summer. I can’t help from thinking whenever has anyone ever heard someone say “ man I can’t wait to get home to take a lukewarm shower “. I don’t think it’s worth it in the winter months. When I’ve been outside working in the cold weather all day I look forward to getting home getting in a nice warm or should I say hot shower. I guess it would be ok in the summer. If the system cost $5000 to $8000 where’s the savings over time? Don’t get me wrong I enjoyed the video. Really helps me to know I’ll not be getting rid of our hot water tank anytime soon. . Been thinking about a tankless water heater though. A buddy down the road has one and never runs out of hot water. The only time it uses any electric is when you turn on the hot water.

[@NJRESolar]

The system has back up, tankless electric, so regardless of whatever is in the buffer tank it’s always plenty hot

[@tomkelly8827]

With Natural gas rates right now in Ontario, it looks like you would have saved around 10cents on one of the shortest days of the year. My guess is you could make about 50 cents worth of heat in summer this way. $15/month then. $3/mo in Dec, Jan, Feb. I live in Ontario and I'm planning to use my PV panels to heat water once my batteries are full. No outdoor plumbing to freeze that way. I heat water and my floor with a coil in my cookstove firebox for winter. It works very well.

[@silpakrishnan5605]

I want a video about sofc system with heat exchanger

[@anthonydoyle3613]

Converting form BTUs to kwh because that's what I am used to, I make it about 5.1kwh per day, on this short snowy day. This would be enough hot water for two people I think. Its not enough to heat a home (but I think US homes tend not to use hot water for heating as we do in the UK). However its an impressive result considering the snow. What's it like in summer?

[@johndulku]

Hi. Thank you for the video. We are thinking about solar thermal to heat our school's greenhouse. What was the exterior temperature at the time you removed the snow from the tubes? I apologize if I missed it being mentioned in the video. Cheers. -J

[@boblebricoleux4498]

in Celsius would be even better...

[@93Badash]

tip 100 fahrenheit is near human body temperature

[@hund4440]

@@93Badash 100°C = water boiling 0° = freezing water In my opinion this is more relevant in everyday use ( like weather, cooking )than the 100°f = body temp 0°f = arbitrary Besides that it can be easily converted to kelvin which is important since it is the SI unit

[@beebob1279]

With American and international viewership the presenters need to start showing both. When I’m seeing celcius temperatures I keep an extra window open with the conversion chart to know the f temperature

[@johnnylawson1329]

do you have a heat sink?

[@RichM-vc9on]

It would have been much nicer to see the data charted using Excel or such.

[@bjleau76]

With the price of Pv panels now, would you still invest in this or go pv hot water?

[@NJRESolar]

Incentives for PV is far better. Put a heat pump hot water and make it all by PV

[@NJRESolar]

The system would cost about 5k to 8k depending upon where you live. The variable in costs is typically around the installation costs. This is before any state or federal incentives. The federal government also has a 30% tax credit. Many states have many rebates too. If you can handle the job yourself, you could probably do if for under 4k.

[@northernozarkhomestead]

Where does a person shop for one of these panels?. How do they work in the Midwest where cloudy days not bright sunny, but cold days like in the Rocky mountains are normal? How is unwanted heat disbursed during the summer time?

[@vladimir0700]

Good effort but that's a lot of expensive hardware that has to be purchased, maintained and, eventually replaced. Also, I find that showering in water below about 103F starts to feel rather cold. Is it really worth it compared to just using electric or gas?

[@SimonASNG]

He is using solar as a pre-heater. He showed an electric on-demand hot water heater that makes up the difference... It is a lot cheaper to take solar heated water from 90 up to 116 than city or well water from 55 up to 116. These things pay for themselves with energy savings in a few years and they last as long as copper and glass last (much longer than photovoltaics). It probably came with a couple extra tubes and you can buy more for less than 40$ each.

[@1timby]

OK ... let me get this right. This only raised your temps to a luke warm shower temp. So you still needed the backup to get the water for a shower. I realize that it's only having to raise the temps from 60ish instead of near freezing. Down here in the south it would take a long time to pay back the system. I use NG to heat my water. Typically the temps are in the upper 40's during most of the short winter and we get a temp boost in the summer as temps are in the 90's and low 100's.

[@guilfreehotwater1174]

where do u get your censors?

[@robertsilvers5807]

That is only $1 in electricity at 0.21 $ per kWh. $1800 in PV modules (6x300 watt panels) would have made the same amount of electric on a December day, but would have been larger.

[@huwkelvinmorgan3575]

i would add a photovoltaic solar cells a single one off switch that shunts all of the power of the solar on the roof and out the back garden into that boiler via a low voltage heating element just to bring it up to a minimum of soon as the tank reaches the correct temperature either a timer switch or a temperature switch would chuck the solar power back into my battery bank that way your not waiting all day to heat up your tank.

[@jcanivan]

nice video BUT snow is a problem because the tubes are so well insulated no very little heat from the tubes is available to melt the remaining snow BUT I guess if you are serious about collecting heat in the winter evac tubes could work. I herd there are leek problems from time to time.. I prefer DIY collectors.

[@urghize]

John Canivan what I like is a combination of both. Cheap flat ones, since they are easy to come by nowadays anyway, good for collecting ambient light. And 1 vacuumpipe for the colder days.

[@stephenleung83]

msa1985 Because evacuated tube is more efficient in cold climate then solar flat plate. In warmer climate, flat plate usually more efficient.

[@TheRebelmanone]

Where is the general location this was done? It will matter if you are in Maine or Canada, i mean i know you said alot about light and heat in the description, but nothing tells us your general location. I seen the snow and i seen the 30 degree temp but that is not the entire story, the rest of the story is where you are at in relation to latitude and longitude. This gives indication how much sun energy you can capture, the angle you are at with the sun is more direct the farther south you go knowing the sun is in the southern hemisphere in the winter.

[@patrickcote2392]

What about a really cold day and night..say...minus 30 F. Do the pipes burst from freezing?

[@SimonASNG]

The exposed tubes are all using a glycol solution and the collector its self uses some sort of molten salt that can't freeze. They use these in Alaska. All the "water" in the system is safe inside the house where it belongs.

[@jairo33]

what do you do with all the hot water in summer?

[@urghize]

FJ J We have cusomers who like to "dump" exessheat into the usualy too cold and damp cellar, or the ground under the greenhouse to prolong the season.

[@percy832]

I thought the water temp in the tank needed to be at least 120f to stop bacteria. Not having a combined system is a bad idea.

[@rokag3332]

ozone + UV

[@dougelick8397]

Wo what did this system cost? I've thought about adding a heat pipe system to supplement my old school, cast-iron radiator hydronic heat system, but don't know about the payback. I happen to be lucky in that half of my roof is unobstructed, about at 45 degrees and facing due south.

[@SimonASNG]

Ha, I just replied to a 9 year old comment ;) Moving on now. ;)

[@ybaggi]

Ok, 17412 BTU are about 5.1kWh, right? At about 25c/kWh, you just saved or produced $1.3 assuming 100% efficieny in an electrical heater. So let's say $1.5. that's $45/month. How much did your installation cost so as to determine the return? thanks for the great video and I'm jealous of your snow..

[@robertsilvers5807]

+Yves Baggi Electric heaters *are* 100% efficient.

[@Andytlp]

these things only pay off in years...its true worth lies being off grid as much as possible.

[@vitaliypro8441]

I don’t think they ever pay off, not in US at least.

[@MrBazsi888]

What is better ? HEATPIPE or DIRECTFLOW ?

[@paulmaxwell8851]

My system uses SunRain heat pipes. Made in China. Excellent; perhaps not as ruggedly made as Sunmaxx but very high performance.

[@marshallscreekfarm3833]

where can I find a tank without a heating element?

[@NJRESolar]

Google Sunearth energy products

[@Caseycallender]

So it almost gets hot enough at the end of the day to take a decently warm shower in the winter. But isn't hot enough to he considered hot water at any point. Even at that, you would be using all hot water of you wanted a warm shower and no cold making the reserve tank go away very quickly. I think it needs some work still.

[@NJRESolar]

Not sure what you're trying to say here. BTU's are BTU's. We heat the tank the most we can with the sun. Thats all savings. What ever we can't heat, we heat with tankless electric, which give us another shot to use the sun since we have solar PV. If we don't have enough solar PV, we use the grid. Its a perfect system.

[@Caseycallender]

@@NJRESolar exactly what im saying, at best this is another "possibly" cost efficient solar add in that is probably not worth it..

[@NJRESolar]

@@Caseycallender In late spring, summer and early fall its likely doing 100% of the hot water needs. Still not following you here. That said, what makes this a harder sell finaically these days are two things. 1- Due to fracking, gas is cheap right now so its not cost competitive. 2- other solar options have more incentives so its not something most people start with on their homes. These systems are used all over china and india.

[@NJRESolar]

Not exactly the case, agreed that this system cannot handle 100 percent of my needs, 10% of this is because of shading. Normally, you will never size a system for 100% winter requirements. This is because during the summer you will have significant amounts of overheating. One exception is that if you have a pool or hot tub, you can dump this heat there. Killing two birds with one stone.

[@jdickson242]

I hope he hasn't responded because he has died from legionella infection. It seems like the system draw directly grom the volume in the tank. It very risky having a tank sit at these temps.

[@NJRESolar]

It does not. Closed loop.

[@terrytytula]

You know, if you raised the collector a couple of feet you'd have less problems with snow.

[@NJRESolar]

agreed, fortunately for us in NJ, it's not that common a problem. I moved the collector when we did passive house addition. There it has a little bit of an overhang, of course during wind that doesn't do much.

[@squee222]

no mention of the ambient temperature outside. Where I am it can get down to -30 -40 celsius. so... sno on the ground means very little to me. big difference between 0 and -40

[@LK-pc4sq]

What part of Canada do you reside?

[@RossABQ]

He showed the thermometer on his tree, it was around 30 degF

[@paulmaxwell8851]

I live in Canada, so similar situation. My system makes loads of hot water down to about -20C (-10F) at which point hoarfrost no longer burns off the tubes. Since my panels are up on the roof I have no easy way to remove that frost so from then on I rely on the woodstove with coil. It's really something to see the hot water I can produce on a winter's day!

[@koreymayo8884]

Wrong! Average temp sensor in tank rose 35 degrees, so only 5,804 BTU for the day, but still doable for 1 or 2 people taking a 5 minute at low water pressure. If you had enough of these panels and tanks and a hydronic floor heating system then your whole house would have free heat! Solar water heating is 10 times more efficient and less expensive than solar electric PV panels!

[@artsmith103]

Actually you are wrong. 35F X 80 gal X 8.35 lb/gal = 23,000 BTU. About 1/4 gal of propane or $0.50. And that is with a huge 30 tube system and expensive control system. I have a 10 tube collector -1 that a deer broke. When the water is hot in the collector the pump turns on. That's it. Barely enough in the summer for 2 people.

[@irishguy200007]

Not much good in Ireland I guess with all that cloud cover.

[@irishguy200007]

So 80 cent will produce the same output?? jeese

[@oby-1607]

This just tells me it is not worth it to install this system. For the cost and where this system is installed (couldn't be worse-on the ground and shaded) for probably around $7,000 there was a 17,000 btu gain. A small space heater does more than that in an hour. Maybe if this was mounted where it should have been (on the roof) and more of them, there would be an appreciable amount of heat gain but the cost would go way up as well.

[@Miniorpernik]

Not really well .Winter is only 3months so ....

[@jimlahey5354]

5:45 I cringe when I see the unit of BTUs. For the sanr people out there that's the equivalent of 5 kilowatt hours.

[@colin.jwhitehead5644]

need to get rid of the music, you can not hear a word. Pointless.