Revolutionary solar heating: combine it with your existing water heater - Video 58

This would be OK for places that never get below freezing but not in Ohio in the winter at night.. I did not see a check valve to prevent water from expanding and pushing the cold water backwards or an expansion tank so the pressure remains low enough.. The systems around here have a heat loop filled with a solution that does not freeze at our cold temperatures and an exchanger that passes the heat to the fresh water in the house.. You would also have to worry about biological things growing in the system that would eventually cause problems.. Simply prewarming the incoming cold water to room temperature does chop a lot off the cost of heating but the expansion tank and check valve are still needed..

[@nnvasen-good-energy]

I pin this answer as I agree that I have not been complete enough, sorry! Our solar system is indeed right ... for us, it is not complete for all circumstances. The important point of this video is that you can put 2 systems together and have the best of both. The existing system is usually designed to supply always water at the same temperature. That's already a lot of benefit. The additional (solar) system can take the role of the money saver and can be as complex or simple as needed. I just would like to trigger a movement of solar exploitation in a corner of the house where so much energy is taken from ... the wrong source. You saw my statistics: only 3% of households in Developed Countries have solar thermal and 30% (10x more) is making hot water with electricity. The electrical grid is stressed worldwide. Let us relax ... it.

[@richardsandwell2285]

This is an easy win, I use solar hot water most of the summer from mid Feb to Late October.

[@nnvasen-good-energy]

Thank you Richard! You are right, the sun is sending us so much energy, people are complaining it's too much. And 30% of households in Developed Countries heat the water with electricity...

[@ajarivas72]

@@nnvasen-good-energy I installed mirrors around my solar water heater and I get 3 times the heat. 190 kilograms of water from 25 °C to 60 °C in just 20 minutes during sunny mornings.

[@nnvasen-good-energy]

That is amazing, a cheaper way to turn surface into energy. Is the "movement" of the sun a problem?

[@MrRamtecs]

Very nice, I am considering a solar water heater . The area where I plan to put it is a tropical area, I wonder what my choices would be if I don’t have an electric water heater? Also, I would need a mixing valve to combine cool water with the hot water so people don’t get burned when washing dishes. I suspect putting a relieving pressure valve as a safety precaution would be good.

[@nnvasen-good-energy]

If you have this thermostat valve, you have a large temperature range where the people even don't notice a difference in solar irradiation. Then the storage volume is an important variable for secure supply. Good insulation is most important with higher temperature and a high temperature allows also to have less volume and still the same energy.

[@nnvasen-good-energy]

So the thermostat allows to live without electric heating.

[@waltermessines5181]

Goed gedaan jochie... From a fellow NL expat.

[@nnvasen-good-energy]

Hoi Walter, waar ben je als expat, in Italia? Hier zeggen ze dat wij als peterselie (prezzemolo) zijn, het groeit overal.

[@waltermessines5181]

@@nnvasen-good-energy Portugal, al 20 jaar, maar overweeg om terug te keren naar Brabant... Niet echt dat ik Carnaval mis, maar wel de "gezelligheid"...

[@nnvasen-good-energy]

Ja, ik zit al 34 jaar in Toscane en Sicilië en denk af en toe terug aan mijn studententijd in Eindhoven. Portugal schijnt ook een schitterend land te zijn. Is het niet beter om Brabant uit te nodigen daarheen te gaan, dat is nog veel gezelliger! Wij hebben hier een Zero Energy Holiday Home (ZEH) en dan kun je er nog van rondkomen dat er kennissen uit NL langskomen: tevredenheid aan beide kanten!

[@waltermessines5181]

@@nnvasen-good-energy goed plan, heb een pandje op het oog, zoek 500K€ ... Mooi groot pand, weinig werk om het op orde te brengen; kan turn-key opgeleverd worden voor die prijs. ;

[@nnvasen-good-energy]

Dat zijn hoge prijzen in NL (toch?), Walter! Maar met duurzame energie maak je het pand zeer interessand. Wie weet, hoe hoog de energieprijzen dan zijn. En voor de hittegolven heb ik gisteren een andere video uitgebracht.

[@charanvantijn541]

This is a good possibility for using more heat from the sun. But have you looked at solar diverters? I use the SOLIC 200. It's been working flawlessly for years now. Nearly free hot water during 8 months of the year. Plus no water lines outside the house.

[@nnvasen-good-energy]

That's indeed a smart solution, especially for video 63! There the problem is that the PV energy actually *must* be avoided to flow into the grid, if the energy meter doesn't distinguish the direction of the energy flow (in/out). That must be tried. I will say it to our friends, which actually have this problem. Thanks Charan!

[@markthomasson5077]

Good idea…but as others say, many problems, and PV is now best. If you DIY, yes worth considering. That said, my neighbour, in Scotland, just got PV for 100% grant! My dad tried something similar in the 80s. House in Devon UK. It preheated a very large header tank. Before we moved it act started boiling! The idea was to drain in winter…but an early frost caught it out, sprung a leak, to never work again.

[@nnvasen-good-energy]

Yes, I know also someone that had a frost and it was irrepairable. With DIY you can at least make things modular and exchangable. Or take measure before the event occurs. It would be nice if the manufacturer made these solar collectors error proof. We are so used to the simplicity of PV that solar thermal seems fragile, but many other things also need elementary care and maybe we are more used to those.

[@mungewell]

For cold climate look at drain-down systems, which use a small pump to only fill the collector whilst the sun is shining.

[@Gary-wh7ce]

New subscriber from Michigan, USA. Nice video / content on hot water heating and not wasting precious energy. I use solar to run air conditioning in the summer and resistive electric heat in the winter for one large room (20 square meters) which does help a little with the bills. Learning a lot and not listening to the politics on the subject but plan to expand more in the next home and enjoy retirement without the high bills or worries should a grid fail in the area. Keep you the good work sir. Ciao. Gary

[@nnvasen-good-energy]

we had 2 weeks ago guests from Michigan in our Zero Energy Holiday Home (ZEH)... Thank you for your encouraging words and hope you will have a nice retirement time. Reading that you use PV the whole year around you might be interested to see this video 25 and the next four of the 25-series about a current project I am improving about a mobile airco that I use with double efficiency because I use both cold and hot side of the heat pump circuit. kzbin.info/www/bejne/bHy1i36MmNlgq6c We have also a political issue: our state supported PV system with grid connection is commanded to go down during a black out and that seems to be a safety prescription also in other EU member states. Even if I would just switch off our system from the grid during blackout, it seems there decision that we may not enjoy independence during the blackout. It will just shut down and not even charge the home batteries. Is that the same in the United States?

[@Helderhoofd]

Thank you for explaining!

[@nnvasen-good-energy]

Graag gedaan (your name tells me that we have the same native language)!

[@lauriev]

Logical good sense approach, thanks.

[@nnvasen-good-energy]

Glad it was helpful, Lauriev!

[@stevepailet8258]

I have decided for my climate zone 4 in the USA to do a drain back system Evacuated tubes 30 tubes. 10 gallon drain back tank located inside of the house. it heats up a 50 gallon storage tank so there is a pump to move the water thru this system It will be supplied by a photo voltaic panel so water only is pumped during the day if there is sufficient sun. There will then be connected via a heat exchanger to a 50 gallon heat pump water heater. there will be another small pump to move the water from the drain back to the HP.wh Like you the hp water heater will be centrally located so no plumbing run will be over 20 ft. Figure the vacuum tube does not put out as much heat as a flat panel but is should be able to produce 12000 btu of water per hour

[@nnvasen-good-energy]

I wonder why there are so few evacuated tube collectors. In Mauritius (I had a Renewable Energy project there) there was plenty of them. High quality and also for colder climates a good solution, with less heat loss. Is zone 4 sandwiched between north and south, and then running the north west coast? Should be like my native country, the Netherlands. You have quite a complex system it seems, but nothing against that. Important is that it is all under control. By the way, I just bought the Home Assistant system and want to make videos about it, should be a control solution to run this complexity, or do you have another system? Arduino should also be good.

[@downtoearth1950]

I am in Australia I have an Evacuated 22 tube solar hot water system 315 litres

[@nnvasen-good-energy]

Then I think you have nice high temperatures in the hot season! You can dilute the water so virtually your storage is bigger.

[@johnjoeflanagan]

Very helpful tips here, thank you.😊

[@nnvasen-good-energy]

Glad it was helpful John!

[@nickwinn7812]

One could equally store the pre-heat water in the house closer to the final water heater. It is rare for the storage to be on the roof for any format of solar water heating in northern Europe, for the obvious reasons that the losses would be greater and the consumption of water is unacceptable due to the long pipe runs to draw-off points.

[@nnvasen-good-energy]

That's a good point. Certainly they have worked on the problem of heat loss and long tubes to the end user.

[@richardross7219]

Similar to what Mother Earth News Magazine showed 50 years ago. Your system is nice but, what happens when the weather dropps below freezing?

[@nnvasen-good-energy]

See my pinned answer, above. The news that I try to bring is to make a hybrid, maintaining the old system, so that the additional system (here solar) can be simpler and even DIY. And yes, unlike with our system, you have to take care of freezing.

[@stevepailet8258]

this question is exactly why I am doing a drain back system.. no water in the system on the roof susseptable to freezing

[@richardross7219]

@@stevepailet8258 Depending where you are and how cold it gets, the drain back systems can run into trouble in a power outage. I prefer hot air systems because they are cheaper to build and leaks aren't a big problem. I built my house passive solar 30 years ago. I works well when we get sunny days. Unfortunately, the number of sunny days per winter has greatly reduced in the past 30 years. Good Luck, Rick

[@nnvasen-good-energy]

Good point Richard, working with air. Certain configurations can even work with cooling, if you make the so called "Trombe"-wall, which can draw air from a cooler place (under the house or north side).

[@markthomasson5077]

Feels mean to diss your good work..one final comment Used PV panels are very inexpensive. If these are connected directly to a low voltage DC immersion heater in your tank, with a thermostat, you have a very cheap simple system. There are other KZbin videos showing this.

[@nnvasen-good-energy]

No problem, Mark, for a good comment. In the first place I like very much your idea for its simplicity: high safety and no inverter needed, at least it can be dimensioned 1.2 kW less. You can even put other PV panels closer to the heater because there is more current (100 A with 1.2 kW). However, the PV has an efficiency of about 15%, even if that might be a bit better with variable voltage (that's why I like the simplicity of your solution) and solar thermal is at 65% or higher. That is a big difference, but as also other comments reveal, many in the audience are concerned with the technical problems of solar thermal, while PV is so simple. And you made it even simpler: I don't see any need for other components other than the cables and a (thermostatic) switch.

[@markthomasson5077]

@@nnvasen-good-energy yes, if you have limited space, and a high hot water use, thermal could be a good option. I understand self contained units are / were very common in many hot countries.

[@nnvasen-good-energy]

I was for work in Mauritius and saw many vacuum tube collectors

[@markthomasson5077]

Is that not a huge weight to be putting on a roof?

[@nnvasen-good-energy]

About 300 kg, yes, that is like 75 kg on each of 4 fixtures.

[@opera5714]

All solar is local. These systems sound nice, but they come with issues. I've seen these on rooftops and after a couple years they get removed. I have a thermal unit and have never installed it. There is no place on the roof that gets sun most of the day. I heat water with excess PV and panels can be placed anywhere. The purpose of a water heater is to have it turn off soon and then it is just useless junk on the roof. PV can be used for anything. The marketplace eventually figures it out. In more than a half century this technology hasn't made it mainstream.

[@nnvasen-good-energy]

Hi Opera, you have a nice channel going on, I saw already some nice video that I want to watch. You make a very good point. Solar collectors have a lot more that can happen. I would not accept that as a fact, because solar thermal has the merits of having much more conversion efficiency and to work even if covered by a bit of shadow.

[@nnvasen-good-energy]

I also have complaints about the temp that our collector reaches and will ask the manufacturer. However I liked so much the idea af an hybrid and keeping the old system and its proven advantages. I wanted to show that idea on youtube.

[@nnvasen-good-energy]

I also hope that many DIY like my brother at minute 13 will be induced to make a colle tor, even simple. With the guarantee of hot water it will be less daunting to try it. There will be no problem to sell a cold shower to your house mates.

[@opera5714]

@@nnvasen-good-energy My channel would be better if I bothered to learn to edit. They are very technical and I don't see myself as a personality. My PV hot water designs have been built around the world, even Tiera del Fuego. I got a kick out of that. I don't know if you do home repairs, but plumbing always turns into a nightmare. Give me wires anytime. The vast majority of YT viewers are only voyeurs and never build anything.

[@opera5714]

@@nnvasen-good-energy Some add an extra pipe and a pump to circulate the water thru the water heater. As with most things, a simple idea can easily become more complicated.

[@Snerdles]

PV seems like a better usage and then just use a solar hot water preheat tank as an energy dump for excess solar. If you really want thermal hot water then make a mount that you use regular PV solar panels cooled by the water, again in to a preheat tank and then you collect the thermal energy and also the output of the PV will be better thanks to being liquid cooled. A pure thermal collector doesn't seem yo make much sense though, now that PV is so efficient and cheap. Running the piping and making sure the roof weight limits are still within spec, plus having piping on your roof is already a liability in case of damage or equipment failure.

[@nnvasen-good-energy]

Sorry for the late reply, I am working on another KZbin channel on GHG Accounting. I like very much the idea of solar CHP (Combined Heat and Power) and in a short video I mention that. However, it is hard to find those PV panels. Indeed they run better if cooled as you write, but it must be well below 70℃. However, solar thermal is not too expensive, our 3.2 m² should give some 2.5 kW so that is really 1€ per Watt. And the efficiency is much higher (about 65% against 15%). You are right about complexity. I've been working now on hydraulics for the next Saturday video and ... it is not so easy as it seems, and plumbers are not easy to find (here). But diversity seems me a good principle. Indeed we have 6 kW PV against those 2.5 kW solar.

[@normyanke2515]

In northern latitudes we can use data for solar PV, that works at full power for little more than 10-12% annually, but for six winter months about 3%, and almost 0% in dec. and jan. In summer you make too much hot water, and it cannot be stored. Unlike solar PV which can be stored in batteries or sent to the grid, your excess summer hot water has no value. Therefore the actuall value might be something like 4 or 5% or less of annual costs. There will be no payback in most of the world. In sunny climates.....its obviously much better.

[@nnvasen-good-energy]

I partly agree. I am a nordic person (NL) living in Italy, I know the difference. This difference is not so dramatic in the amount of kWh per year on a m² of solar surface. Therefore, PV is popular also in northern countries. Thermal energy can be stored. Heat 30 litre of water 30℃ in a (bigger of parallel) water tank and you store about 1 kWh. That can be done at a much lower cost than with batteries.

[@redrockcrf4663]

@@nnvasen-good-energy I've gone even more basic - when the sun is hot enough I just put a camping solar shoer out on the patio and usse that to shower later, or for dish washing water. Spent a few dollars about 30 years ago and still using it.

[@nnvasen-good-energy]

Simple but effective!