Monday, January 13, 2014

Solar System Thoughts

We are considering our solar system.  We are going to be grid tied!  This is necessary because of many reasons, first and foremost, Arleta is on Oxygen and needs it for her concentrator.  Otherwise, it will be nice to have for our computers, appliances, and of course to help with the farm.  That said, we are still looking at getting off the grid, just differently.  We are now going to be moving off the grid over a period of time, much easier to do by the way.

So with that out of the way, here is the basic plan to get off the grid.

First we are going to get the barn completely off the grid, well because for the most part there is very little that needs to be on the grid.  Even our milking equipment is relatively low demand equipment, and so we can get that off the grid pretty easily.  Initially we will actually start completely off the grid, as we will only have the sheep, and we won’t be milking them.  Therefore, all we need for the first install is a single light and an immersion heater so the water doesn’t freeze in the winter.  This being said we still will need a solar panel, a charge controller, a battery bank, and an inverter, as well as the basic breaker box, breakers, cables, and other such electrical appliances.  The reason we are only going to have one light is that I do not like to have the light on in the barn at night, it disrupts the normal sleep cycle of the animals.  We are going to also have an immersion heater that will only be used in the winter, to keep the water from freezing.  The immersion heater will be set on a thermostat switch, so that when the water temperature starts to get below 36 degrees the immersion heater will kick on, and when it goes above 55 degrees it will switch off.  This should protect the water from freezing solid, although in really cold weather it might still form a layer of ice on top, which is really not much of a problem.

We cannot use a CF bulb in the barn for the same reason we need an immersion heater, once it gets really cold, the CF bulb will not work.  We will have to use an incandescent bulb, that will stand up to the rigorous use of the barn.  Therefore we will purchase a “rough service” bulb, as it will work best in this application even though it is not the most efficient type of bulb to use.  We may consider LED light, but again I am not certain they will do well in the conditions of the barn, especially in very cold temperatures.

We will also have to power the heat tapes that will be used on the water supply pipes that are above the frost level to allow the float to continue to work.  This will also most likely have to power the auxiliary pump that will pump the collected rainwater (or snow melt) from the winter tank into the water feeder.  So you can see there is quite a lot of stuff to really power in just a little barn for sheep and chickens, mostly so they can have water.  Still it is a system that can be easily taken off grid completely as it really doesn’t require that much energy.  The immersion heater is AC, or at least I have not found a DC model that is both reasonable in cost and sufficient for our needs.  Therefore because of this and the light bulb we will need an inverter.  However we can use a small DC pump, as well as DC powered heat tapes, which are readily available and relatively reasonable considering how efficient they are.

We will be using, at first, a single 12 volt solar panel, connected to the charge controller, and the charge controller will then be connected to the small dual battery bank, still set up for 12 volt system.  We may also be incorporating a small 12 volt wind generator to supplement the solar power system.  This is the power generation system, and will be about all we will need, except that it will not be the system we will be using once we build a new barn with milking capability.

I will most likely build the system to be essentially portable, so that later I can use it as a portable power station for off site projects.

On with the project, we will also be working to get our entire compound off the grid, through a slow build up of a grid-tied system.  This will incorporate solar panels added to the system in 24 volt pairs, 24 volt charge controllers, batteries in 24 volt banks, and lastly, twin inverters, in 24 volt to 240 volt configuration.  This is why it will take a longer time to free ourselves from the grid, as we will be looking to build a system that is rather expensive, and does require a certain amount of building to get to the capacity that we will need for full operation.

We will also be incorporating a wind turbine system, but that is for another time, as that will require additional research to determine how to tie that into the system.

We are also looking at heating water, and again this is a subject that should be addressed at another time.

Our first installation will consist of two 24 volt 100 amp panels, a single 24 volt charge controller (300 amp max load), 4 12 volt 125ah batteries in series parallel, tied to a single 24/120v true sine wave inverter.  I had looked at (am still looking at) the “grid tied inverters” as they are called and decided that it would be better to have the shunting mechanism outside the inverter, so that we could add or change the system without changing the grid tie.  Of course this system is not really going to do much for our power consumption, with the exception that on good days we will reduce dramatically our draw on the grid, costing us less in the long run.  However since we are going to be adding to the system on a fairly regular basis, the cost savings will be negated by the continued investment in the system.

Our final goal is to get to a 14kw system through a means of various power generation systems, with any overage being shunted off to the grid, in a way to pay off our cost involved in the building of the system.  We are already quite conservative in the use of electricity, however we do have a few appliances that use quite a bit of electrical power.  First would be Arleta’s oxygen concentrator, then her portable one (it has to be kept charged).  Second would obviously be our refrigeration capacity, a small efficient refrigerator freezer (uses about the same energy as a 60 watt bulb), and a medium sized freezer (used to store meats and other items).  We also will have to supply refrigeration to our milk house and creamery, so we can process milk, but that too is relatively small considering our small amount of milk we will be working with.

Then there are the pumps.  We will have the main well pump, which we will be using a 240 volt pump because they are more efficient.  Then we have the grey water pump, a small 12 volt pump that will pump the grey water up to the summer cistern, or out of the winter cistern as needed.  We will also have an even smaller 12 volt pump that will pump fluid through the solar hot fluid exchanger, which will heat most of our hot water.  I am not going to go into great detail here about the hot water system, although just for edification, I will put a small sketch here, to show a bit of what the collector will look like.  This is obviously a quick sketch, and I will go into much greater detail with much better diagrams (I hope) when I do present that aspect of the project in its own document.  It really just breaks the text up a bit and adds a little interesting diversion from the printed material.  Moving on, where were we?  Oh, solar grid tied system, usage appliances, there we go.

So, our usage is already quite low, with only critical systems really needing to be tied to the grid, but since we are tied to the grid, it only makes sense to tie the entire system to the grid, giving us the ability to use our appliances as we wish, and still save some money on our monthly power bill.  We do have a TV, it is a 32” Samsung Smart TV (LED LCD) which uses less power than other TV’s we looked at.  It is tied into our network, so it also acts as an additional AP for our wireless network, and as the media server.  So yes it is plugged in all the time, although not always on, it is always drawing power.  It also has a USB plug that is plugged into a charging station, for charging our phones and other devices that use the charging station, this is always on as well.  However it does provide many services to us, as an entertainment system, as a power source for our charging unit, as an AP for our wifi network, and as photo viewer when we want to look at nice pictures while we are working in the kitchen.  I don’t know if I can set it up to handle our cell calls, but I know I can use a camera and microphone to make Skype and G+ video calls on it, so I don’t see why we can use it for hands free calling on our phones as well.

We have other computers too.  No surprise there, we make a major portion of our income from the internet and I myself from the computer itself.  Arleta has a laptop, and although it is mostly hers, like my desktop that has her as a profile for her, I too have a profile on her laptop, so we can use either depending on what suits us.  She also has a phone that she can use on the wireless to access the web or local content as well.  I have a desktop which is my main computer, it is used for my work (remote services) and for my play (PC games), and we use the massive storage in it to act as a NAS on the network.  For this and other reasons it is on most of the time.  I have done my best to limit the power consumption, and the NAS is available even while the computer itself is in hibernation mode, so that cuts down on the power consumption.  I would like to build a SAN/NAS as it would mean we would not need the power computer online to provide NAS service, but for now that is not possible, and it would be just one more always on appliance.  In addition to this we also have a gateway computer between our broadband network switch and the internal network switch.  This computer is also always on, but it is very efficient and does not even have a monitor or other peripheral connected to it, as it only provides IDS/NAT/Firewall service, as well as security services that I can not really go into.  We have the network stack, an ISP switch that connects us to the broadband provider on the other side of the DMZ, and a Wireless router that is connected to the DMZ computer, and to the TV providing network switch services, and as the primary wifi AP.  We also have another laptop I use infrequently to boot into the network, and for other minor things such as that.  Lastly we have a subwoofer and speakers connected to the TV, the same connected to my computer, and a small video studio where we make videos we post on the web.  That is about it.  Our hot water is heated through the use of a solar collector, boosted by an on-demand water heater that is fueled by propane (now, but switchable to nat-gas or methane), a wood stove that provides most of our heat (we do have a small very efficient electrical back up system), as well as a gas/wood cook stove which we use for our cooking.

Including the eventual farm equipment, the shop equipment, and the home, we will really only need about 10 kwh of power generation to serve our needs.  We will off load the rest onto the grid until we feel we are ready to take ourselves completely off the grid, at which time we will then double our storage capacity so that we can off load our extra power into the secondary battery bank and the rest will be shunted off to earth ground if necessary.  Our needs may change in the future, so we wish to build at least 14 kwh system to ensure that we will have the capacity to handle any new demands for other services.

Yes I am considering backup systems, and redundancy, I am afterall a computer geek, so yes I have them figured in and no I am not saying what everything is, as some things are just kept for ourselves, as you just can not be too careful these days.  I am a bit paranoid sometimes, and so yes I have considered that, and to some degree I have figured that into our plans, but I also have to balance that against the fact that often I am paranoid sometimes, and I can not let that determine our conditions just because of my personal concerns of security.

However if any of you want a system that does take into consideration all of the concerns that a person prone to paranoia may have, contact us, and I will personally assist you in building a system that will not only ensure that you will have power no matter what happens, but will have security even from the worst of humanity, or the government, which ever one or both concerns you the most.

Well that will do for now, I will obviously revisit this subject several times as things get going on the new homestead, including maybe some video of some of the systems.  Look for me on G+ and contact me if you have any questions or concerns that we can help you with, we will do what we can.  Thank you all for taking the time to read this, and I hope it shows a little of what can be done.  I know there isn’t a lot of detail here, but we are working through the actual parts of the system, this is just the skeleton sketch of the system and we will release more details as they become known, including actual brands of products that we use, and why we chose those products over others.  Thank you again and have a safe and secure day, if you can.

James and Arleta Doud

Doud Dairy Farm

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