Solar Power System for Housing

Once upon a time there was a story about Donald Duck, who bought a typewriter because it would solve all his spelling problems.

dear u need to contact a firm who is doing a solar power projects

they only have a software or data sheets related to how much power you want to generate using solar power and how much cells you required of what size

you're doing it backwards, first, add up all your requirements in KWh, then begin shopping different solar configuration set-ups. you may or may not require the components in various packages. I also suggest you buy Andy Germany some beer so he'll give you a tutorial on batteries before you spent any money on them

Currently total off-grid power adds roughly $20,000 to the cost of a new 1500 square foot home with all the normal conveniences.

The only PV system with batteries for 20 grand is a small off grid cabin system. I have one. It's cool, and makes no sense financially, except I am not connected to the utility, I don't have a mailbox, phone line, water lines, gas, you get the picture. It's perfect. These numbers are turnkey installed. You DIY's can subtract about 30%. And if you think you can do it as well as we can, go for it. Most can't

Next up, a system still too small for most people, is for a house that uses 1000KWH per month, with two days of autonomy in case of poor performance from weather (this would be a very slim safety margin) and sizing a battery bank to remain above a 50% depth of discharge in order to get a reasonable life from the battery bank, in the mid Atlantic area, with a PV array with perfect orientation an NO shade (I don't mean just a very sunny roof) a system costs about $80,000. This is down from several we built in the early 2000's for over $200,000. If you want to change your lifestyle to hermit mode when the batteries are low, it can cost a lot less.

A grid tied system, with a 20KW NG genset for unlimited offgrid backup, is about $38.000. A straight grid tied system would be around $30,000. (It would not be very useful in a grid outage, although the new SMA inverters offer a small AC output (1500 watts) that can operate small charging functions when the grid is down but the sun is out, which is great for computers and cell phones. Grid outage averages less than three days per year east of the Mississippi. Lot's of capital to deploy for a very small benefit.

Seems expensive? You are going to buy a lot of fuel in the next 20 years. (electricity, diesel, NG, etc.) Can you avoid that by investing now? With the existing 30% Federal tax credit, you will get about a very good return, especially if you pay over .12 cents per KWH, and it is a grid tied system.

Add batteries, and you are buying a luxury item. It will not be financially feasible, like granite countertops and Porsche 911's. Trying to tar and feather solar PV because you want battery backup is ridiculous. Trying to tell people you can buy a whole house system for 20 grand is also ridiculous. If you spend 100$ per month (1000 KWH at .10), that number will increase by 5% a year for the next 20 years. That is a huge cash flow, which you can use to finance your PV system and provide a sufficient return. It is not out of the question. It is good business.

I can't see an economical case for a PV system that is off-grid. The outright cost is huge and the batteries need replacement on a periodic basis, adding to the cost.

However, living in Florida I am looking for a DIY solution to provide some partial power for a few key systems in my house when a hurricane disrupts power for extended periods.

The last big outage was quite a number of years ago and my girlfriend was without power for 21 days. We are due for another at some point.

I am thinking that enough power to service a small window AC unit and maybe a refrigerator would go a long way to making such an outage bearable.

The best financial payback for solar (in Florida) is a solar hot water system.

I think the issue with DIY in our state is that it makes if difficult or impossible to qualify for the tax credits.

Any HVAC (even a small window AC) puts the size requirement into the much bigger than small Solar PV category. Buy a generator, especially if you have NG. or propane and a couple of 40 pound tanks. You can move them to the filling station if you have to, or get a bigger fixed tank. You'll need at least 4KW for the smallest AC. I would buy a whole house 14 or 20 KW, and hardwire it with an Automatic Transfer Switch. You probably won't do this with a smaller unit.

Fuel acquisition, storage and noise are the issues.

When the power goes down fuel resources become scarce and undependable.

Storage of that fuel is an issue. The best alternative is a large buried propane tank.

A noisy generator is not only a disturbance, but a big flag that tell desperate people you have power and resources inside.

The generator may be the only real alternative in the end. I will know more after completing a full energy audit and prioritizing my needs.

Under an emergency situation there are many things I can do without. We don't have to live the life of royalty, just survive the ordeal with the basic necessities.

Same here, AH. I have a small battery PV system, an Air-X wind mill, and a genset. I manage demand/supply by adjusting lifestyle with availability of resources. My genset monitors state of charge on the battery bank, which powers the emergency load panel through an AC inverter. It is strictly an UPS. We build systems professionally. I have propane. I am not worried about showing people I have resources. This is disaster avoidance, not conspiracy theory. The life you live is 1000x more important than the life you fear. I think preppers are fools, because they waste resources. They may have the last laugh. So be it.

I'm working on a small wood fired boiler/steam driven genset. Seems biomass fuel is the most likely to be available, but not very clean. It is carbon neutral though. It's very exciting to be in this era of fuel source disruption, but really it is nothing new. It's all about the money it takes to power our lifestyle, but now a lot of people actually care about the status of the ecosphere called Earth. Solutions are rampant, but are very disruptive to entrenched capital. It's inevitable that, like nuclear weapons, we find a way to control environmental destruction, or destroy ourselves with pollution. Not in my lifetime, sure, but maybe in my kids or grandkids. I'm confident we'll figure it out, not with standing those of you who don't think it is all that critical. (read, not worth the money) I do love a soapbox, and really enjoy this forum.

The only thing I am "prepping" for is hurricane and fire. Both can drive you out of your home.

For hurricanes I can usually shelter at my home (providing it isn't a Cat 5), so a month's worth of food and enough power to run the essentials is prudent. However, I don't have the resources to help a block or more of others knocking on my door that have neither.

I ordered an EFergy Wireless Home Energy monitor to get a handle on what exactly uses what.

I was thinking that another tact is to use a battery pack recharged by a generator. That way you could rapid charge the battery pack on a periodic basis rather than run a generator continuously. Sort of like the way a well pump works with a precharged pressure tank.

Lastly, I really don't see how 'preppers' waste resources. First, there are not that many of them. Second, FEMA and other government websites advise the whole public to keep stores of food and other necessities. Have a look.

So, it's not like these guys are doing something that they shouldn't be doing. They may be doing it in excess, but then again, most people do absolutely nothing. They are ones that become the les miserables of society and the resource cost of rescuing them is much, much higher than the cost of simply preparing. How many billions of dollars has FEMA spent on natural disasters in the last 5 years?

We keep two 3-day bag of essentials (clothes, personal items, ect.) for each of us that we can grab if there is a fire. I learned that lesson when a close friend (colleague) had a small house fire. Not a lot of fun standing outside naked (or nearly so) waiting for the Red Cross.

Everything they owned had to be cleaned due to smoke and water damage. The house damage was relatively small, but they were displaced for months while they waited for everything to be fixed, cleaned, and returned to them. I got the day-by-day story. Most of us read about a house fire in the paper and that is the end of it. Not so for the victims.

Yes, you are right about natural disaster preparedness. I didn't mean to lump that activity with the TV version of preppers, which is nuclear/conspiracy theory driven. It is their money, they can spend it how they want. It seems wasteful to me. My sister runs a smoke/water cleaning company. It is very tough for those people who suffer fires.

Genset with battery is a pretty good solution, since the variety of charge options is so large. That is what I described in my reply.

Why do you like FL, the weather or lack of low temps? Just curious. Getting to know your personality through CR4, you do not seem like a FL guy to me.

It was a business decision. My business partner lives here and we want to locate or consolidate our company in one location.

I have spent most of my life living in the boondocks or farmlands in the North East, so this is a paradigm shift. I can say that I much prefer the warmer weather than the cold wet winters of some of the places I have lived. Fun when you are a kid, but wears thin after awhile.

One other advantage with Florida is that cars stay a lot cleaner down here (excluding the salt spray along the ocean). I sold all my other cars and just drive a sports car every day, all year long now. Never could have done that anywhere else.

We get about 2 months a year where it gets really hot (and humid). That's far less than all the months of winter in the North East. Also, we top out at about 95° for the summer, which has been a lot cooler than some of the places up north.

On successfully functional refrigeration:

It has been interesting adding an ounce or two to "full refrigeration 134a charging of 183 grams".

we are airconditioning "draped" spaces in large rooms and isolated from whole home areas with under 160 watts/hr for a few hours , nearly daily in Amish communities.

Literally a surround is placed in for to just contain the needed cooling from a solar storage set up.

Fridge Boxes from Sunfrost, CA, are 60 watt and 90w for the large one.

Good answer to OP: search and find your calculator that your thread requested- there is more than a few.

resulting answers with comparisons are helpful figures of costs and outputs above and throughout! thanks.

You're talking big money again. I've installed 20KW/ATS systems on Sanibel Island back in the early 2000's with automatic start-up for both power failures and short service runs to keep the engine oil up in the cylinders. They are not cheap and require permits and development orders because of the noise/bitchy neighbor factor.

For my own house in SWFla I just ran a second set of feed wires, in the form of a motor home extension cord, into my breaker panel to a spare 100 amp breaker and unhook from the grid via the main grid disconnect while the 5K generator is running. The cord hangs out the back of the house and is long enough to put the generator outside in the back yard while it is running.

As Anonymous Hero said,

Go here, first↓
Searching The Internet - Exploratorium
Then, after learning how to search, you will find all the answers, by yourself, freeing you from having to ask others how to find things like:
Solar Power Systems - Complete Home Solar Systems

It would appear from the Solar Power Systems website supplied by Lyn that a 5000 watt off-grid whole house system can be bought including batteries for $20K.

My point about an off grid system for $20K was that it would be easy to design it into a new house along with many other proven energy saving and collecting ideas now in production and even if you need a huge side-by-side 48" Sub Zero, they are now so energy efficient they use less electricity than a standard 100 watt light bulb.

Dehydrating toilets, LED lighting, 12 volt small appliances, and dual fuel stove and fridge like they use in motorhomes, solar heat for water and home heating needs could augment dual fuel water heater or small on-demand water heaters and geo-thermal HVAC is already perfected.

If a flowing creek is available water can be used to pump itself up into a cistern also.

Almost all the replies and comments stress one thing: Cost of storage of electricity. Thanks to the reasonably low price of poly crystalline silicon PV panels, production of power is far cheaper than it was, say about 5 years back. Cost of other components, such as wiring, has gone up, due to very high pricing of copper. DIY, of course is the only way to being down the cost, and hardly five per cent of people are DIY inclined.

With this scenario, solar energy with its short and uncertain availability, would take a back seat compared to the far more convenient fossil fuelled generation of electrical power.

Perhaps the best way to utilize solar power on a large scale would be to have electrolysis of sea water in coastal locations in a big way, produce hydrogen, collect it, and transform it into electricity by burning it to produce water, and be happy all the time. All it would need is replenishment of sea water in the electrolytic cells. If and when solar energy is available. It would be just converted to hydrogen, which is eminently storable.

If you have to ask you can't afford it.

First of all find out the total energy requirements of your appliances and whether they are designed to run on 120V, or 220V AC or they could be run on 12V DC.

If they could be run on 12V DC, it would be very simple. Due to resistive losses, you cannot have long leads and have to use a much thicker wires. If it is AC, then you need to have an inverter of capacity at least 20% more than the total energy of your appliances (When used simultaneously)

You do need a battery back up, which should be about twice the energy requirements of your appliances since you have to take into account ain-less days also.

Then come the solar PV panels. The total capacity of the panels evidently should match your energy needs + about twenty percent so that there is no under capacity. You need a charge controller for the batteries so that they are not over charged.

I'll try to be constructive. This an example of how not to design an energy system to satisfy a demand scenario. This is like deciding how much fuel to put in an aircraft by determining it's top speed.

You need to audit use over time. It's not easy, but it forces you to evaluate the potential impact of alternate strategies, such as improving efficiency, often done by investing in superior equipment. It's a cost/benefit approach.

There is no software that will answer these questions, unless you have the data. You can't get the data from a placard.

You kind of do estimate how much fuel (power/energy) to put into an airplane (vehicle/house) based on it's top (most efficient) speed over the distance you want to go. Carry too much and it cuts efficiency (cost per mile/day).

If you oversize your solar panels you are able to take advantage of the short charging times on cloudy or short days so a capacity overage of 20% or more has two advantages, you don't come up short on amperage and your charging time is reduced.

Trip calculations between points are static. (it's always the same distance and in a particular aircraft, with a particular engine; it requires a given amount of fuel, within a few points.)

A grid connection to a house, and the service rating in amps IS a good analogy.

Solar system design is not, unless it is grid tied. When the grid is absent, new criteria must be adhered to.

You cannot know those parameters with a solar system. At any given moment in time, you cannot decide on how much fuel will be added, (beause of the variable nature of solar radiation, and weather) and don't know how much output is required (because of the variable nature of HVAC requirements, lighting, other loads, etc.) You don't know the state of charge (fuel on hand) at any given time. These three variables make robust systems very challenging to design. Disregarding them is not an option.

This concept is most difficult for many people, and is a source of poor system performance, which is regrettable, as it damages the industry. I am not implying that people will not accept a compromise, I'm implying that it is easy to misrepresent the system. I know that to be true, because I have built a lot of them. I've worked with several reputable electrical engineering firms who also fail to comprehend the design requiremnets of solar, because of the relience on equipment placard data. Variable supply is a bear.

Depends on how variable the passenger list is.

I understand the variable factor of sunshine, except maybe in St. Pete, Florida where the St. Pete Times has had in it's front page heading for decades that the paper is free the next day if the sun doesn't shine on St. Pete during the course of a day.

Unless you live in a desert, I would suppose a 5-way off-grid system would be mandatory with solar water heating, a wind generator which would have the possibility of working through the night many nights a year and a solar array attached to a bank of batteries sufficient in size to get you through two or three days of bad weather and a back-up generator of course.

Geothermal heating and air conditioning generally uses a low flow volume calculated to the air handler flow requirements so the well pump can be a DC pump which would seem to me to be more efficient than an AC pump though I'm not sure if they make submersible DC pumps or not. Steam heat from a remote wood or coal burning steam generator could be used in snowy regions. My brother has had one in Iowa for years now to help heat his 5000 square foot house.

If rainwater were channeled or pumped into a cistern via a 12 volt motorhome style pump and then pumped into the house using gravity and a make-up pressure pump for toilets, washing, etc., energy requirements for water use could be kept low.

I moved back to Florida in 1973 just to get away from 45 days of no sun in Bloomington, Indiana. It was from November to mid-December with temperatures in the 30's and 40's so in that circumstance you'd be up a creek without a paddle so to speak, and totally reliant on the generator.

One thing that has not gone Energy Star is clothes dryers. Very difficult to hang your wet clothes out when temps dip below freezing.

...."they make submersible DC pumps or not."

yes

and DC a/c units aforementioned

and

3 phase dc used in VFD a-lot-of-things

I want to add to this discussion.

Solar panel for residential use must first start with your existing power requirements. You must do a home audit before you can do anything else.

The first step is understanding your individual appliance needs - then considering what you can do to update those appliances to reduce your loads.

When you start this way you potentially reduce costs in 4 ways:

1. Electrical demand

2. PV Solar panel size

3. Charger/Inverter size

4. Battery size

The last three are the big cost savings. Cutting your daily consumption from 12 kWh/day to 8 kWh/d can reduce a huge chunk of up front cash with the system.

So, reconsider the cost of updating appliances, LED lighting, and other things that improve the energy consumption efficiency of your home. It pays off big.

The second consideration that few people think about is system losses.

1. PV Panel loss - manufactures rate their panels with a ± tolerance, so you should factor in the possible loss (i.e, ± 5% - so figure worse case = -5%)

2. Heat - PV panels loose efficiency as they get warmer. You could loose 10% in summer.

3. Dirt - dirt on the glass will reduce efficiency about 2%

4. Wiring losses - 3%

5. Inverter/Charger 7%

6. Battery 30%

You can easily have 50% or more system loss. You also need to consider panel aging loss.

Given that you need to size your system bigger due to these losses, reducing your energy needs first is a must.

On an excel format

one could plug in the results we had in 1980: One ~ 8x3 ft air-solar collector delivered the power of heat energy at the rate of over 3000 btuh in Dayton Ohio, normal to the sun in the summer.

Air Collector copied after the Solastar(tm) series then:

Three yoder industries 500F baked window-screens-layered

1.5 inch thick poly-iso-foam-foil-inside lining bottom of the solar box and sides

all layers of the screen 3/4 inch apart as well as the clear-er TFE layer 'buffer' above the screns towards the sunlight, and that TFE layer just under

FILON or solar glazing-

Framed in galvanized 24 gauge metal boxes and top edging ~

about 100 cfm peak for a 25- 30F temp rise

4 collectors "cooked" 1500 sq ft in a 3000 sqft avg home of the 1970's in February 1981.

This would work better if he had painted the siding black inside the collector. I'm planning to try it on my little house in East Tennessee so I'll tell you how it works out next month.

http://www.wholesalesolar.com/pdf.folder/Download%20folder/Load.evaluation.worksheet.pdf

Breaking news....

Insurance will be getting harder and harder to get for solar powered homes. Seem fire fighters won't go into houses with active solar panels because they cannot actually turn it all off.