Building new Off Grid Home in Panama

westbranch · April 2013

Re: Bulding new Off Grid Home in Panama

PT, Re: the 'heat sink' you have for walls.... is it possible to add some insulation or reflective paint to (or shade) the outer skin to defer/deflect the sun light/heat elsewhere? The cooler the structure the better. Though shade might not be so good for PV power.

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Westbranch - looking into reflective coatings, paint, etc to do just that. Insulation on cinder block construction would probably put the locals over the edge regarding the "gringo" effect. They do not like change as I mentioned before. Even if we find a suitable product, getting it here is another question. Nothing is made here, everything is imported.

Cheers

Ernest

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Did a Lat-Long find for our location. Hope I state these correctly:

8*471 N Lat 80*007 W Long

Cheers

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Reflective Coatings - Paint

Found this site:http://reflectivecoatingsinfo.wordpress.com

Interesting synopsis:

"CERAMIC PAINTS CLAIM TO INSULATE AND TO REFLECT HEAT

Ceramic-filled or so-called ceramic insulating paint additive technologies promoted by several companies claim to be an”insulating” paint panacea to make exterior house walls cool have been a nonsensical concept from their outset based upon just one law of physics. Since insulation and it associated mandatory “R- value” measurement in the building industry (R for resistance) have been long established as the measure of effectiveness for insulation. This is based on thermal mass (thickness & density) and in some varieties, effectiveness in trapping air inside the thick barrier or dense product. Average paint thickness is a single sheet of paper. Now comes the two sheets of paper thick ceramic-filled paint (up to TEN pieces pieces of paper for some manufacturers), and the claims of insulation value when used to paint any type of exterior wall. Buildings coated in this way are claimed to be so cool so as to be compared to the space shuttle in how it is protected by ceramic tiles in re-entry to our atmosphere. This is all smoke and mirrors since the very basis for the R-values claimed cannot possibly be achieved for any substantial length of time by thousandths of an inch of any paint film with insulation elements (ceramic or hollow glass) mixed inside of it.

The paints that are said to insulate do not use the IR pigments at all and would be seen to rely upon the insulative idea for the gains they promise as opposed to true reflection of the infrared, thermal wavelengths from the sun, which heat up surfaces in contact with direct sunlight."

This seems to support the sentiment expressed earlier. Still looking for the a solution.

Cheers

mike95490 · April 2013

Re: Bulding new Off Grid Home in Panama

Decide if you want the thermal mass inside (slow to change temps) or outside. You can purchase/rent a 2 part spray foam machine (The big city there should have them) and insulate with that, wrap with wire mesh and stucco (outside) or drywall over
it for inside. ( sorry if this is a repeat - I've not read the prior 100 postings. ) It will make portals a bit thicker, so trim will need to be figured out.

Or roll down bamboo or reed shades will shade the walls, they would last about 2 years maybe.

Cariboocoot · April 2013

Re: Bulding new Off Grid Home in Panama

Corrugated metal roof panels painted white on the sun-exposed walls, mounted 6" out with air gap top and bottom. Best with insulation barrier behind it, but it sounds like 1" rigid foam is unheard of there. Someone should explain to them that insulation can help keep you cool as well as keep you warm.

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot - lots of items that we take for granted are not reflected here or available. The more expats that come here, the more it will change, but like up north, it will take time. A lot of change up north came from legislation, not volunteerism. There is also a mindset that it is good enough for Panamanians, so why not you.

Have found additional information on reflective coatings/paint from Aussi sites. One company has a product that is energy star rated. Another provides demonstrative proof that their product works. A lot of research down under considering their climate is similar to here, and government wants to conserve - good incentive for industry partnering with government to achieve an aim. Here are the web sites:

Astec paints - Energy Star Rated - good YouTube video
http://www.greenpainters.org.au/Consumer-Information/Heat-Reflective-Paints.htm

http://www.shieldcoat.com.au/why-choose-us

http://www.brighthubengineering.com/building-construction-design/83701-ceramic-thermal-coatings-vs-paint-for-houses/

http://www.hytechsales.com/prod1000.html

http://www.heatreflectivepaint.com.au

Just some evening reading.

Cheers

Ernest

Blackcherry04 · April 2013

Re: Bulding new Off Grid Home in Panama

I would assume that vegetation would grow like crazy there, I'd take a look at whats out there that you could plant to give you a screening effect on the house. I don't have a green thumb, you might get the seeds or started plants shipped to you. My neighbor planted some kind of a Bush / Tree that grows vertical that has made a huge difference in the afternoon sun he used to get. If they grow to high, they will kill your sun on the PV's, that may be a issue. I also see people using that sun shade stuff they use on Green Houses, it's easy to find online and comes in different light transmission densities. The ones I have seen are on a stretched cable and you can slide it like a shower curtain.

I am with Coot, I'd be looking for some rigid foam board for your interior walls. It's cheap, compared to the payback.

Just a thought.

solar_dave · April 2013

Re: Bulding new Off Grid Home in Panama

When I did my new office/shop building here in Arizona I had to fight with the contractor to do 2 inches of exterior ridged foam over the 2X6 walls. It just isn't done he complained and he had to make the flashing up special. Guess what, I ran the mini split yesterday and the worst hour of the day with 95F outside temps and 4 computers running for work with 6 displays, the load only went up about 0.5 kWh for the peak hour of the day and most of the day it was about 0.3 kWh as compared to a non AC day. I am sure the added insulation helped. I wish my house was built like that.

I seriously looked at spray foam for the wall cavities, the price was just astronomical.

You want to save $$$$ on the AC bill don't scrimp on the insulation.

Surfpath · April 2013

Re: Bulding new Off Grid Home in Panama

Panamretiree wrote: »

Thanks for the info Bill. Have to look at everything to get the inside cooler without the use of AC. Was at a friends house for dinner, cinder block construction the same as ours and the west wall in her bedroom was very hot - cinder block houses are heat sinks. This led to a discussion on this.

Not much insulation in these homes. had to arm twist the builder to accept our requirement for attic insulation and roof vents. They do not accept change very well here.

Hi Ernest,
I experience lows of 22/23c and highs of 29/31c & lots of humidity.

With this in mind I researched and designed a low humidity, temperature controlled house using most of the same materials they seem to use in Panama (from your photos).

I have a min max weather guage in my home and it varies from a low of 22c to a high of 27c with an average temp of 25c. My house is natually airconditioned.

It's got a:
-White reflective metal roof
-large cement block (8" throughout)
-High cathedral ceilings with an easily accessed window placed fairly high up for those really hot 'summer' days.
-I imported fiberglass insulation batts (R22) and designed an unvented roof assembly.
-Except for the one window (see above) we have no others. So there is constant air flow throughout house, even when we are not home. I installed heavy duty screened metal shutters (they also act as 'burgler proofing') with outside clips that allow for the addition of storm fabric if need be.
-and white painted external walls help reflect the afternoon sun.
-the house is positioned with it's longest span going E-W. This means that less of the side walls of the building face the morning/afternoon sun.

CMU block buildings can be hot, moldy boxes if heat and humidity are allowed to permeate and stay in the building envelope. However, if humid air is allowed to exit constantly, and if surfaces that receive direct sun are reflective and well insulated, then they can be wonderful structures.

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

BC - are you and Coot bachelors? - I'm not and I don't know how the better half would take this type of change. On the brighter side, we have been to the house every evening and watch progress during the day. We are confident that we will have significant shade for the walls. We have discussed plants and such and will be putting them in with the caveat tat the solar panels are not to be impacted. If we impact on the solar panels, why do this at all.

Cheers

Ernest

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

SurfPath (hope the name is because you do surf - going to give it a try here - the waves at El Palmar are quite something) - we are having the exterior walls parted smooth so that in the event that we need to do anything to the exterior it can be. Even a 1/2 inch rigid insul board at an R-3 rating would make a significant difference without changing the exterior a lot. You can go over the rigid board with raging and make it ok like any there house. if we considered putting rigid insul board on the outside walls we would only have to do the south end of the house. I'm for doing almost anything to get the heat signature inside the house down.

We are having exterior decorative grates over all windows, and metal-gated doors. This is so we can leave the windows open and not loose our personal effects, and for our personal security.

The attic will be vented, and the ceiling insulated.

Cheers

Ernest

Blackcherry04 · April 2013

Re: Bulding new Off Grid Home in Panama

Panamretiree wrote: »

BC - are you and Coot bachelors? - I'm not and I don't know how the better half would take this type of change. On the brighter side, we have been to the house every evening and watch progress during the day. We are confident that we will have significant shade for the walls. We have discussed plants and such and will be putting them in with the caveat tat the solar panels are not to be impacted. If we impact on the solar panels, why do this at all.

Cheers

Ernest

Bachelor .....lol, I could say, I wish. Mine knows that living in a shipping container wouldn't be much fun. I saw you were a boater, we live 9 months a year on ours so were together 24 / 7. We have a 78 ft boat, so we each have a end. I think mine gave up at about the 30 year mark as it being a lost cause to try to change anything about me or what I do.

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

BC - we lived on a 40 foot Bayliner Bodega in WestBay Marina in Victoria. I had a job that had me away one week a month. Close quarter living is a test for sure. It was my dream to do the live aboard thing. The Mrs was a trooper, and now I'm supporting her in her dream, living in the warm. Always wanted a bigger boat, not in the cards right now. Still miss the water.

westbranch · April 2013

Re: Bulding new Off Grid Home in Panama

Well guys my SWMBO "training plan" was brought to fruition by 'only' supplying her with a few lights first, all 12v DC, then adding an inverter to run her laptop so she could be at the cabin and do some of her consulting work, ... one thing at a time eh?... then she was doing some spring cleanup and said to herself, 'hell we've got an inverter' (600W), I'll just use it rather than go start the genny, and KABLOUEY the lights went off and the vacuum was silent...??? What did I (she) do??? Oh you just blew the last fuse we have for the lights.
Now she really knows about how much power she can pull... She double checks every time now;)

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

On the boat we had an amp meter situated directly across from the galley. We watched it religiously. We had a 30 amp service and a 50 amp service. The 30 amp service operated the heaters, the 50 amp service ran the boat. Like you say, education was really the issue. The Mrs also started to realize that controlling the humidity in the boat was the key element in having a comfortable interior. I would have to say that this is also the case down here. Don't quite know how to do it if al the windows are open. We really only have to ensure the bedroom is dehumidified. Working on making this a reality.

Continuing on with the lighting load survey Should be done in another day or two then will publish.

Like the SWMBO acronym, in my case, since SWMBO is not here, I make all the decisions, it's my universe and I like it.

When I get the system in place do I get to have a signature block like you fellows?

Having a few cerveza under a hot sun.

Cheers

Ernest

BB. · April 2013

Re: Bulding new Off Grid Home in Panama

Anytime you wish...

Just click here and add your signature:

http://forum.solar-electric.com/profile.php?do=editsignature

And on your last, or next post, check the box that says "Show your signature".

And you are done. (see your last post 8)).

-Bill

westbranch · April 2013

Re: Bulding new Off Grid Home in Panama

Sig line? YES even if you are just ordering, it helps understand you query, and we don't have to ask the simple questions...

Just remembered a few nights in Fiji, temps all > 30* C and sticky humidity...every day... we just came from the Red Center of Australia, +50* C and <10 % RH, we were traveling around the big island and had never used a ceiling fan till one motel , coldest night since we had left BC at -30* C.

Fan was directly over the bed, on Low speed, ended up looking for another sheet to keep warm, we knew what it would be like without the fan...
hth

Blackcherry04 · April 2013

Re: Bulding new Off Grid Home in Panama

I hear you, I started mine off with a 3500 watt Inverter, that was a mistake. I bought a 1300 watt Outback GFX1312, it will surge to 1800 w for 30 minutes. It is like a miracle, I now have plenty of battery backup and when I run the generator she's getting the stuff done that use to be done on battery power, With " Generator Support " it's changed everything.

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Just completed the LED light load consumption trials.

Had 1.5, 2, 4 and 6 watt LEDs on for varying times.

The load test data is below:
Lighting - Actuals

Type/Volts/Watts/Kill-A-Watt Meter Measurement in kWhs/Time for Trial in Hours/Actual Watts
1.5W LED 120 1.5 0.050 21.11 0.002

2W LED 120 2 0.030 11.11 0.003

4W LED 120 4 0.120 22.12 0.005

6W LED 120 6 0.080 12.12 0.007

Put these readings into my load analysis and it changed the numbers upward.

Here are the photos of what I used:

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Here is my latest lighting load spreadsheet:

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Working on My System wish list - have a good idea though.

Cheers

Ernest

Ralph Day · April 2013

Re: Bulding new Off Grid Home in Panama

I've got one similar to your 6w one in a lamp. Have you tried them in an open ceiling fixture by any chance? How do they do?

Ralph

westbranch · April 2013

Re: Bulding new Off Grid Home in Panama

One Question, what is the difference between K-A-Watt reading and the final Watts in your table (which appear to be in Kwh)?

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Ralph Day wrote: »

I've got one similar to your 6w one in a lamp. Have you tried them in an open ceiling fixture by any chance? How do they do?

Ralph

Going to put it in a 4" pot light. Will be comparing it to a 50W INC. Found this in Panama city, cost $12.50.

Were you ever in the Navy?

Cheers

Ernest

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

westbranch wrote: »

One Question, what is the difference between K-A-Watt reading and the final Watts in your table (which appear to be in Kwh)?

The difference is that the K-A-W meter reading is time based. I divided the K-A-W meter kWh reading by the number of hours logged to give me the hourly watts. As I have started to realize, in order to get the advertised output, there is a requirement to put more in.

For example the first LED is 1.5 W. The actual power usage is 2W (.05kWhs/21.11hrs).

I think my math is correct.

Cheers

Ernest

Cariboocoot · April 2013

Re: Bulding new Off Grid Home in Panama

You do know the K-A-W will read Watts directly, saving a lot of math. So if the light is rated as "1.5 Watts" and the meter says "2 Watts" when it's on .... you can easily extrapolate the Watt hours over any given amount of run time.

Pity they don't like to tell the truth about these things, eh? If it uses 2 Watts it uses 2 Watts, not 1.5 Watts. Light output needs to be rated in Lumens, not Watts, and should also have a number for colour temperature.

It's just easier to say "60 Watt equivalent". Easier to lie that way too.

Still I envy the price. I guess we're not really serious about saving energy in Canada. :roll:

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Have been perusing the web and the different forums here, and have come to realize that getting batteries for a solar system imported may not be the most cost effective way to put together a battery bank. There isn't much choice for the rest of the system. I also think I read a post by Cariboocoot that a person should get the most economical battery that fits the requirement.

Have found Trojan T-105s here for ~$265.00, I do wish I was back home, but I'm not. Have to pay 7% tax so the cost is ~$283.00 a battery. For a 48VDC battery bank this will be ~$2264.00. T-105s are 225 AH, so this battery bank would give me:

112*48*.75=4 kWhrs/day of power. My load analysis indicates a daily usage of between 4.8 to 5.5 kWhrs/Day. It could possibly be less in reality, but we do not know yet. I also saw one post where the fellow asked SWMBO if she could get by without using certain appliances, he guessed the silence meant no.

I've read and considered all aspects of parallel and series battery strings, and think that a parallel 48 VDC system would give more than sufficient power, allow for 8 to 12 305 Watt panels to be installed. Another advantage would be similar to what I read by Chris Olson, in that he can take a battery bank off line for maintenance and still run his house. Going with a 48 VDC system keeps wire size down to a minimum, and allows for a single inverter/charger to run the house. When considering a 24 VDC system, there may be the need to run 2-inverter/chargers for a creeping power load (the sentiment on this site is that if you build it, it will grow).

The system that we are considering will have to be imported and the main ingredients are:

8 to 12 - 305 watt 7T2 Helios panels
MidNite PV6 Combiner Boxe(s) - only one needed for 8 panels
MidNite Solar Classic 150 CC - I believe I read that this CC can be programmed for load applications
Schneider XW4548 Inverter/Charger - I like the operating characteristics of this unit - a lot of talk about this one on the forums
Schneider XW System Control Panel
Bogart TM 2025A Trimetric AH/Volt Meter (used its little brother on our boat)

Keeping the batteries out of the equation is a good idea I think.

I would use 2/0 wire for the battery bank and hooking up to the inverter.

I was considering the 24 VDC system primarily for the installation of 24 VDC ceiling fans, but have been doing some research and the 24 VDC Vari-Fan CFM of ~3600 is equivalent to the westinghouse industrial fan 56 inch at 1/2 speed. The power is comparable as well at 30 watts. Using the 120 VAC fans would mean I would not need a 48 to 24 VDC converter. Will be buying one and doing a trial on it with the K-A-W. They cost ~$60.00, cheap test if it works out.

Another consideration is the Schneider XW4024 inverter/charger is rated at 4 kW, and is just under ~$200.00 less (as I mentioned may need two - not a lot of savings).

I am still looking for batteries here, maybe find some L16s, had the Trojan L16H on our first boat, never ran out of power, Surrette, or others. Nothing is simple in Panama as nothing is made here, everything is imported.

Cheers

Ernest

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

You do know the K-A-W will read Watts directly, saving a lot of math. So if the light is rated as "1.5 Watts" and the meter says "2 Watts" when it's on .... you can easily extrapolate the Watt hours over any given amount of run time.

Pity they don't like to tell the truth about these things, eh? If it uses 2 Watts it uses 2 Watts, not 1.5 Watts. Light output needs to be rated in Lumens, not Watts, and should also have a number for colour temperature.

It's just easier to say "60 Watt equivalent". Easier to lie that way too.

Still I envy the price. I guess we're not really serious about saving energy in Canada. :roll:

Found it, would have made all that extrapolation unnecessary and given me more time for cerveza. Doing a test on the iPad speaker, it reads "03' when I go to the watt reading, so this indicates 3W - yes?

Leds differ in price here. The 4W LED that I did the trial with cost me ~$22.00 USD here in Coronado. Went to the Discovery Center in Panama city and it was $12.50. A huge rip, but I now know where to go.

Hate being lied to or deceived, this load analysis has really opened my eyes.

Cheers

Looked at my initial load numbers just from the info on the appliance. The iPad speakers wet 1.8W, instead of the 3W actual

Ernest

BB. · April 2013

Re: Bulding new Off Grid Home in Panama

Yes, 3 watts... Note that digital meters appear to be very accurate and repeatable... A K-a-Watt meter is probably accurate to around 10% +/-... And ad the extreme edges, may not be (i.e., that could be 2.5 or 3.4 watts--and it "picked" 3 watts). But is still gives you a lot more accurate information than you had before.

Also, regarding your batteries... Remember, we are sizing them for power usage when the sun is down. If you use a fair amount of power during the day--You can "power those loads" directly from your solar array (pumping, fans, computers, cooking, etc.). So, those daytime power numbers do not come off the battery bank, just from the solar array.

Which leads us to the next "issue"... We talk about 5%-13% (could be upwards of 25% rate of charge if it makes sense for your system) rule of thumb rate of charge... A 225 AH @ 6 volt T-105 battery would "ideally" be around 10% rate of charge or ~22.5 amps. On a 48 volt battery bank, such an array would be:an--

22.5 Amp * 58 volts charging * 1/0.77 panel+controller deratings = ~1,695 watt array

But, lets say you have a 10 amp @ 48 volt load during the day (~580 Watt load for fridge/fan/computer/etc.)... That reduces your charging current to the battery bank to ~12.5 amps, or just over 5% rate of charge.

You can see a desktop computer (200 watts), a fridge (140 watts running 1/2 the time), network, printer, fans, some task lighting, etc... And it would not be hard to run close to 500 Watts average loads during the middle of the day at times.

So, that reinforces conservation (laptop vs desktop computer) and why we don't like to suggest a 5% array for an off grid setup if there is any power usage during the day--There is just not enough power to get that battery bank back full during the sunny day--and takes even longer to recharge a bank if the clouds roll on past.

Lastly, if you missed it--Here is the link where you can edit your signature:

http://forum.solar-electric.com/profile.php?do=editsignature

-Bill

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

BB. wrote: »

Lastly, if you missed it--Here is the link where you can edit your signature:

http://forum.solar-electric.com/profile.php?do=editsignature

-Bill

Got the link, put the system in one of my last posts.

Cheers

Panamretiree · April 2013

Re: Bulding new Off Grid Home in Panama

BB. wrote: »

Also, regarding your batteries... Remember, we are sizing them for power usage when the sun is down. If you use a fair amount of power during the day--You can "power those loads" directly from your solar array (pumping, fans, computers, cooking, etc.). So, those daytime power numbers do not come off the battery bank, just from the solar array.

Which leads us to the next "issue"... We talk about 5%-13% (could be upwards of 25% rate of charge if it makes sense for your system) rule of thumb rate of charge... A 225 AH @ 6 volt T-105 battery would "ideally" be around 10% rate of charge or ~22.5 amps. On a 48 volt battery bank, such an array would be:an--

22.5 Amp * 58 volts charging * 1/0.77 panel+controller deratings = ~1,695 watt array

But, lets say you have a 10 amp @ 48 volt load during the day (~580 Watt load for fridge/fan/computer/etc.)... That reduces your charging current to the battery bank to ~12.5 amps, or just over 5% rate of charge.

You can see a desktop computer (200 watts), a fridge (140 watts running 1/2 the time), network, printer, fans, some task lighting, etc... And it would not be hard to run close to 500 Watts average loads during the middle of the day at times.

So, that reinforces conservation (laptop vs desktop computer) and why we don't like to suggest a 5% array for an off grid setup if there is any power usage during the day--There is just not enough power to get that battery bank back full during the sunny day--and takes even longer to recharge a bank if the clouds roll on past.

-Bill

Thanks for the info. Let me just reiterate what I am reading. Battery size and type determine the charging requirement - agreed.

The load analysis really has to be further refined into two parts - daytime and nighttime. I can use this because down here it is almost an even 12 hour split. From this the battery size can be determined - primarily to power the night loads. Once this is done, look at the array size to determine what size array would be required to charge the batteries during the day and provide solar power to operate the day loads.

My understanding from discussion down here that it is very rare when there is not at least 3 1/2 hours of sun time to charge batteries. With this in mind, the solar array would need to be sized to achieve this aim, and power daytime loads.

So my next task is to source the types of batteries I can get in Panama without having to import, and further refine the load analysis into daytime-nighttime.

Using your figures, and I expect you were looking at a single string of T-105s, not a parallel configuration, I would need to have an array size of ~3300 watt array. Using the panels I am looking at, 12 at 305 watt= 3660 watt array.

I have some refining to do. Thanks for the input.

Cheers

Ernest

Building new Off Grid Home in Panama

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