To add my 2 cents if you a DIYer than you can start small and add on as funds allow. 

 

If you are paying for installation then it's better to save up and install one time to save on installation costs.

1 hour ago, Limpopoboy said:

@BraniI agree about starting small but I am in a little bit of a predicament with that option.. But My concern is do I go all solar while I haveing the mess of house building or HW and cooking LPG with the rest solar during construction? I don't really want to not install gas, then find once the house is built I perhaps should have installed gas.

Gas for cooking is just so much better not just from an energy efficiency point. Why do you think restaurants and chefs only cook on gas. I've been cooking on gas for over 15 years now and would never go back to cooking on electricity. If I was building a new house, gas for cooking would be integrated even if i was not going solar. I use one 19kg gas bottle per year for our gas stove and we cook every day.

I agree with Achmat that gas for cooking is the way to go, we also use it, although a lot more than Achmat, more like a 9kg bottle a month,  will be looking on cutting down on that a bit with a induction cooker for cooking whilst the sun is shining and excess energy is to be had, but would not turf gas, the potential battery implications it would have otherwise, make gas a no brainer.

As for HWC, I still suggest the solar option, evacuated glass tubes etc. there is nothing preventing you from putting in line a run through gas heater unit, if the water temperature isn't up to what you expect, but assuming its a tad colder than you'd like and you *have* to use a run through gas heater, at least you won't have to heat up the water from ice cold, yet again saving in the process...

Edited March 7, 20215 yr by Kalahari Meerkat
HWC addition

4 hours ago, Achmat said:

Gas for cooking is just so much better not just from an energy efficiency point. Why do you think restaurants and chefs only cook on gas. I've been cooking on gas for over 15 years now and would never go back to cooking on electricity. If I was building a new house, gas for cooking would be integrated even if i was not going solar. I use one 19kg gas bottle per year for our gas stove and we cook every day.

@Achmat Yes, seems to make sense. What about your hot water? Electric geyser or LPG?

8 hours ago, Limpopoboy said:

@Achmat Yes, seems to make sense. What about your hot water? Electric geyser or LPG?

Solar evacuated tubes. It still has the electric element that is controlled by a Geyserwise or can be switched on manually if there is no sun. 

10 minutes ago, Achmat said:

Solar evacuated tubes. It still has the electric element that is controlled by a Geyserwise or can be switched on manually if there is no sun. 

As I understand it @Limpopoboy won't be grid tied, so to have an electric element in the HWC would be no option, since if the sun don't shine to heat the water by direct radiation, then there won't be enough PV based production either.

I suggest that you will not need the gas in additon to the evacuated tube solar HWC, except in extreme cases, where you may have visitors and more than normal amounts of hot water are consumed.

@Kalahari Meerkat am I to assume that LPG then is the sensible option based on no Eskom connection. I don't see me having an evacuated tube, especially if they have a electrical element to them. I don't see a problem with LPG apart from ongoing costs of gas.

54 minutes ago, Kalahari Meerkat said:

As I understand it @Limpopoboy won't be grid tied, so to have an electric element in the HWC would be no option, since if the sun don't shine to heat the water by direct radiation, then there won't be enough PV based production either.

I suggest that you will not need the gas in addition to the evacuated tube solar HWC, except in extreme cases, where you may have visitors and more than normal amounts of hot water are consumed.

 

1 hour ago, Achmat said:

Solar evacuated tubes. It still has the electric element that is controlled by a Geyserwise or can be switched on manually if there is no sun. 

@Achmat I don't think evacuated tubes is the answer as no eskom connection. Also living on a wildlife estate I would be a little concerned about baboon or monkey damage to glass tubes (if we were allowed to have them).  I think I would rather have say 3 or 4 additional PV panels, controller and battery feeding a geyser and geyserwise setup if I was 100% total solar.

12 minutes ago, Limpopoboy said:

 

@Achmat I don't think evacuated tubes is the answer as no eskom connection. Also living on a wildlife estate I would be a little concerned about baboon or monkey damage to glass tubes (if we were allowed to have them).  I think I would rather have say 3 or 4 additional PV panels, controller and battery feeding a geyser and geyserwise setup if I was 100% total solar.

Have you considered a heat pump. Doesn't heat as fast as an electrical element or gas but uses about 1kw to heat the water and could be connected to your solar system instead of having a 3kw electric element in your geyser. 

LPG would be OK for the geyser. I have just not had any experience with them but there are mixed reviews with some complaints about varying hot water temperatures. 

3 minutes ago, Achmat said:

Have you considered a heat pump. Doesn't heat as fast as an electrical element or gas but uses about 1kw to heat the water and could be connected to your solar system instead of having a 3kw electric element in your geyser. 

LPG would be OK for the geyser. I have just not had any experience with them but there are mixed reviews with some complaints about varying hot water temperatures. 

^This.

Many heat pumps have a 2-3000W element in addition to the pump, this can be wired as a smart load on a Sunsynk inverter. Saves the mechanical wear on the pump by using any excess solar power to heat water. It's a very efficient arrangement. Although my own heatpump is not wired that way, I often manually enable the element when I have excess solar energy.  

Guys, I'm assuming @Limpopoboy is in the eastern Transvaal, as I know the name thus should have more than plenty of sunlight to use for hot water.

We have a 12 tube HWC without electrical element etc. and we have no extra way of heating the water here, so that would be my suggestion for @Limpopoboy the only addition I would suggest is that you consider for the future, I would see how it plays out first without adding a gas run through HWC and if it turns out that in the depths of winter, late at night, the water may be a tad too cold for comfort, then adding a gas driven run through HWC to the mix, just for the odd day, when you need more hot water than solar can provide, may be a consideration, but I'd say, note this option and file it away, just stick with the evacuated tube system initially.

Most evacuated tube solar HWC's don't have electric elements to them, you can usually have that as an option, but I don't suggest it unless you are grid tied.

Basically efficiency wise, heating water direct, vs creating electron flow and back to heat via heating element, the electron flow option with heating element is way less efficient and more costly than heating the water directly.

@Limpopoboy something like this, found via Google would be ok, ignore the "can accept electric element" that's for the cloud gatherers, you know, Cape Town, for instance, where in winter you can have multiple subsequent cloudy days where daytime temperatures may not even reach 16degC or so, then, if you were grid tied (you probably would be) an electric element has value. But not for you or me, here in the Kalahari the amount of cloudy days are few enough so as to no be an issue.

To give you an idea about the energy to be had here, we had quite a bit of rain and a few cloudy days this summer, worst period was early January where we had 100+mm of rain over 3 days and few more cloudy ones around that period. Our daily energy production from PV is around the 32kWh mark on a normal day, I'd say, in January we produced 896.5kWh for the month, so not quite all normal days, for the 1st 6 days we produced:
1st 29.7kWh
2nd 20.1kWh
3d 11.2kWh
4th 7.9kWh
5th 15.kWh
6th 35.4kWh
now you can imagine what that would do to solar direct water heating as well, but we had enough hot water over that period, cant recall coming short, so that's why we don't have anything but an evacuated tube HW system. Here, we have not gone through a complete winter yet, so ask me again in September/October how its going, but I suspect we'll be ok.

Just FYI compete monthly measured PV production here... I made changes early December thus prior to that numbers are lower than they probably could have been.
October 2020 - 827.1kWh (26.68kWh avg/day)
November 2020 - 885.7kWh (29.5kWh avg/day)
December 2020 - 917.1kWh (29.58kWh avg/day)
January 2021 - 896.5kWh (28.981kWh avg/day)
February 2021 - 859.8kWh (30.7kWh avg/day)
with March so far sitting at 225.9kWh (31+kWh avg/day so far)
since our consumption tops out at around 20kWh/day, we can afford to waste some energy, problem always is that you have to waste the energy at the time you have spare, certainly during daylight hours and mostly skewed to the middle of the day... unless you can rob a battery factory and get away with it :-), maar jy sal 'n groot trok nodig he vir daardie opsie...

4 hours ago, Kalahari Meerkat said:

Guys, I'm assuming @Limpopoboy is in the eastern Transvaal, as I know the name thus should have more than plenty of sunlight to use for hot water.

We have a 12 tube HWC without electrical element etc. and we have no extra way of heating the water here, so that would be my suggestion for @Limpopoboy the only addition I would suggest is that you consider for the future, I would see how it plays out first without adding a gas run through HWC and if it turns out that in the depths of winter, late at night, the water may be a tad too cold for comfort, then adding a gas driven run through HWC to the mix, just for the odd day, when you need more hot water than solar can provide, may be a consideration, but I'd say, note this option and file it away, just stick with the evacuated tube system initially.

Most evacuated tube solar HWC's don't have electric elements to them, you can usually have that as an option, but I don't suggest it unless you are grid tied.

Basically efficiency wise, heating water direct, vs creating electron flow and back to heat via heating element, the electron flow option with heating element is way less efficient and more costly than heating the water directly.

@Kalahari Meerkat I am in the Northern Transvaal 😁😁😁

4 hours ago, Kalahari Meerkat said:

@Limpopoboy something like this, found via Google would be ok, ignore the "can accept electric element" that's for the cloud gatherers, you know, Cape Town, for instance, where in winter you can have multiple subsequent cloudy days where daytime temperatures may not even reach 16degC or so, then, if you were grid tied (you probably would be) an electric element has value. But not for you or me, here in the Kalahari the amount of cloudy days are few enough so as to no be an issue.

To give you an idea about the energy to be had here, we had quite a bit of rain and a few cloudy days this summer, worst period was early January where we had 100+mm of rain over 3 days and few more cloudy ones around that period. Our daily energy production from PV is around the 32kWh mark on a normal day, I'd say, in January we produced 896.5kWh for the month, so not quite all normal days, for the 1st 6 days we produced:
1st 29.7kWh
2nd 20.1kWh
3d 11.2kWh
4th 7.9kWh
5th 15.kWh
6th 35.4kWh
now you can imagine what that would do to solar direct water heating as well, but we had enough hot water over that period, cant recall coming short, so that's why we don't have anything but an evacuated tube HW system. Here, we have not gone through a complete winter yet, so ask me again in September/October how its going, but I suspect we'll be ok.

Just FYI compete monthly measured PV production here... I made changes early December thus prior to that numbers are lower than they probably could have been.
October 2020 - 827.1kWh (26.68kWh avg/day)
November 2020 - 885.7kWh (29.5kWh avg/day)
December 2020 - 917.1kWh (29.58kWh avg/day)
January 2021 - 896.5kWh (28.981kWh avg/day)
February 2021 - 859.8kWh (30.7kWh avg/day)
with March so far sitting at 225.9kWh (31+kWh avg/day so far)
since our consumption tops out at around 20kWh/day, we can afford to waste some energy, problem always is that you have to waste the energy at the time you have spare, certainly during daylight hours and mostly skewed to the middle of the day... unless you can rob a battery factory and get away with it :-), maar jy sal 'n groot trok nodig he vir daardie opsie...

@Kalahari MeerkatThank you for your feedback. Its all quite mind boggling really. Just difficult to know what to do.

No worries @Limpopoboy, the way I see it is as follows, running electrons is cheap-ish if you can do it as they are being excited/as the sun is providing the electron flow.

If you need to defer the electron flow, you need to store the energy for later use, this gets expensive.

If you have regular wind, you could use this to add to the energy production process with a wind turbine or two, ideally you would have cloudless days and windy nights, then your need for battery capacity would be reduced.

So, based on the above, electric heating, sort of ok, during daylight hours (oven, hot plate cooker), but certainly for when there is no energy being produced and energy has to come from battery storage, it probably is better to look at alternatives, thus gas for cooking/baking is perfect. Microwave is ok, since usually we only run these for short periods, but be aware if you run one at full power, this can consume anything from 600W to I suppose well over 1kW of power whilst running.

Hot water production (bath/shower/washing) also is best done direct, rather than the 2 step process of making electrons move and then pushing them through a big resistor (heating element), your losses are huge if you are going the electron move vs the direct evacuated tube solar HWC. But as I wrote before if the direct route does not give you enough hot water at a late hour, it is still the most cost effective route to take, the water that may be colder than you want should then be run through a gas run-through hot water boiler which, if you have it, you will probably only really use a few times a year in the winter, I would think.

The obvious things that never get mentioned are LED light just about exclusively, fridge/freezer that is A+ rated or better or, maybe a gas based fridge/freezer may also be an option, but I know nothing of these and certainly am happy with a electron flow powered compressor based refrigeration.

Hair drier, assuming it is used in your household can be power hungry be aware that all these smaller appliances/tools/whatever do have an energy footprint which you should be aware of and keep in mind.
Dishwasher, most homes have one these days, its not a problem, but should be run off live power (when the sun is producing plenty, like mid day) rather than off battery power/at night. The same applies to the washing machine. Tumble drier, should probably be skipped, I'd think, but don't have one, so can only imagine the power requirements. I would imagine that drying washing on the washing line in you neck of the woods is probably similar to here. On the line by 9 and by 12 its dry and very warm...

As for batteries, the obvious chemical based candidates are Lead Acid, personally I would not recommend these anymore, prices have gone through the roof and quality/life isn't really there, LiFePO4 based batteries are more prevalent, since they more likely can handle the power/instantaneous power supply more so than most Lead Acid batteries.
Next would be mechanical batteries, which is not really in the realm of home user storage options, huge flywheel in a vacuum sealed case with motor/alternator combo.
Next is chemical/mechanical combo battery like the Redflow's from Australia, too expensive, last I checked, but these have some possibilities as in if a homebrew version exists and lets assume you can get the membrane that will allow you to have 5kW of continuous power draw or charge, then if you need more hours of energy storage, all you'd need to do is increase the liquid container capacities and charge them up...
There are other options like generating hydrogen when power is available and storing this for later use when you need energy and the sun has disappeared behind the clouds/horizon.

Re-visiting batteries, Lead Acid, should probably not even be taken down as low as 50% state of charge, personally I'd say no lower than 80%, meaning you get 20% of energy out the battery before charging them up again, opinions will vary, but if you want to see at least 10 years of life out of these, then I'd say 10 to 20% drain max, which means, if you need, let's say 10kW worth of energy for when the sun don't shine, you actually need 50 to 100kWh worth of battery... also note that most Lead Acid batteries are only rated at C/10, that is if its a 50kWh battery bank, then you can draw 5kW of instantaneous power (around 100A if its a 48V system) else you again are having a negative impact on the batteries potential lifespan. - Quite a few people seem to think that hey, I have 4 X 200Ah Lead acid batteries, thus 48V (series connected) 200Ah, that's 9.6kWh and should see me overnight, problem is, that you should not draw more than 1kW aka 20A out of that battery bank and if you do take the battery down to 10% or less of energy remaining, it likely within 2 to 3 years will be toast.
As for LIfePO4 batteries, these usually can be discharged down to 20% energy remaining and you should be able to expect 10+ years of life, if you stay within this lower limit, personally wanting to guarantee more life, I'd set a lower limit of 30% and even an upper limit of 80% and let the BMS handle things from there, ok this only gives me 50% of the batteries capacity as usable, but staying away from the chemical extremes, close to empty and fill 'er up, should give me a much better life expectancy out of these. As for current draw/instantaneous power, most will do C/2 some even C, so if you have a 10kWh LifePo4 bank, it can produce, assuming 48V, 100A to 200A of current flow.

All I can recommend is read and research more about the subject, the biggest cruncher/costliest affair is the energy storage/battery and since this is the costliest item effectively you need to manage it right and not just from keeping things charged and preventing too low a state of charge, but also from a use perspective, running dishwasher, not off batteries etc.

Edited March 8, 20215 yr by Kalahari Meerkat
garbled clarification...