How about a solar car port on a budget?

[Naam]

10 minutes ago, scorecard said:

My dream is to eventually instal solar on the house roof and get the family electricity bill down to zero, also meaning zero cost to run 3 to 4 aircons for about 60 - 70% of the year.

may you live long enough to see your dream becomes reality. but don't hold your breath.

[Naam]

On 9/1/2019 at 6:35 PM, RideJocky said:

You can refrigerate water during the day and use it to chill your ac unit at night

interesting! does one pour the water into the inside or outside unit?

[scorecard]

7 minutes ago, Naam said:

interesting! does one pour the water into the inside or outside unit?

You put ice blocks in a bowl and use your normal fan to drive air across the ice and cool the room and turn off the A/C.

 

Don't laugh, a couple of decades back we did this and it does work up to a point. 

[Naam]

On 9/1/2019 at 6:45 PM, Crossy said:

 

It's actually better to make ice (latent heat of fusion and all that high-school physics stuff you forgot straight after the exam).

 

Make 1 ton of ice and you can have 12,000 BTU of aircon for 1 day.

 

depending on the ice temperature the btu harvest can be exponentially higher. but so will be the energy cost to cool down an ice block to absolute zero -273ºC.

[Naam]

2 minutes ago, scorecard said:

You put ice blocks in a bowl and use your normal fan to drive air across the ice and cool the room and turn off the A/C.

 

Don't laugh, a couple of decades back we did this and it does work up to a point. 

and from that point onward you are royally p*ssed off because your room has 99% relative humidity.

[RideJocky]

interesting! does one pour the water into the inside or outside unit?

 

Either

 

It’s somewhat common in the US, but not with solar. They chill the water at night when you can buy electricity off-peak, then either use a water-cooled chiller to cool the refrigerant, or use the chilled water directly.

 

 

 

 

 

[tjo o tjim]

3 hours ago, Naam said:

i respectfully but totally disagree. ẟt between 18ºC well water and an average of 30ºC ambient temperature is a feast for every condensing unit enough to increase efficiency exponentially.

True; I was thinking in terms of direct use and not spraying on your condensing coils.  Approach temperature is too tight to get down to a comfortable wet bulb with direct use. 

[DUNROAMIN]

On 8/31/2019 at 1:35 PM, Crossy said:

Ok some photos.

 

The roof spacers look like this, the large (14mm) hole in the top is to allow the driver to get to the head of the self-drilling bolt that will hold it to the roof (drilled through the tile into the roof steel).

 

 

They will work something like this.

 

 

The steel mounting rails primed ready.

 

 

The 600W inverters, each links to two panels.

 

 

And, just in case you don't know what they look like, 4 x 300W solar panels.

 

 

 

 

 

Hi, when you ordered the inverters did it come with some sort of instructions for installation to your existing power source??

[Crossy]

1 hour ago, DUNROAMIN said:

Hi, when you ordered the inverters did it come with some sort of instructions for installation to your existing power source??

 

The instructions are somewhat, er, minimal. But since it's a simple connection of L, N and E to the distribution board it's not rocket science.

 

I recommend an RCD/RCBO protected circuit with the over-current selected to allow whatever your maximum generated power is going to be.

 

[khunPer]

On 9/1/2019 at 1:08 PM, Crossy said:

The problem with renewables, and solar in partcular, is that they are often at maximum production when the load is at a minimum and at zero production (at night) when the load is, if not maximum, certainly significant. So either there needs to be conventional backup (which doesn't start quickly and so needs to run inefficiently at small loads during the day) or we need a LOT of storage (a ruddy big battery).

Yes, the back-up power is the general problem with renewables, when no sun, or when no wind. Been discussed a lot in my windy Scandinavian home-country, where we sometimes generate more wind-power than we can use – we export through the grid – and sometimes quite little production, so we import from the grid. Seems like the grid needs an update to cover this, also with the government intention of changing to electric cars, prohibiting sale of fuel cars from 2030, which demand the existing grid cannot cover at all.

 

Thanks for your calculation, solar energy has become affordable now when compared to normal grid price; your official export-to-grid tarif would probably be much lower than 4 baht a unit. I calculated on installing some solar panels about 10 years ago when building my house, and at that time, with battery storage, it would take some 17+ years to pay the investment back including interest loss, some loss of efficiency over time in the panels, and some maintenance. The major question then was if the life-time was more than 17 years, especially the battery storage, and how many years more it could live, so I decided not to tie up several hundred thousand bath in alternative power supply.

[frank genin]

Gentleman
I am impressed that you dare to do DYI
I was planning to do the same thing since some times
And your exemple is inspiring
Where are you base as i wish to come one day to see it finished
to kick my final decision to do the same !

I am close to Chayaphum on my side and you ?
Regards    Frank

[RideJocky]

Are the batteries renewable?


Sent from my iPhone using Thaivisa Connect

[Jaggg88]

On 9/1/2019 at 9:15 AM, johng said:

Imagine how much power would be produced if every roof top in Thailand was covered in solar panels..they would (probably) not have to import any electric from neighbouring countries and save billions on gas and oil.

 

So true - 360 days of sunshine yet they're talking about building a nuclear power station - madness!

[Crossy]

Well the modem has arrived, I can't get it to work. software expects 4 digit inverter IDs, inverters have 8 digit IDs. Tried just the last 4 no dice.

 

So now talking to the seller but it appears to be a known issue! Grrr.

 

Meanwhile using my quick and dirty monitor (ok my Kill-A-Watt) the system made just under 3 units on a rather dull and overcast day.

 

[Crossy]

2 hours ago, RideJocky said:

Are the batteries renewable?

 

What batteries? This is a grid-tie system.

 

[sometimewoodworker]

12 hours ago, Crossy said:

Well the modem has arrived, I can't get it to work. software expects 4 digit inverter IDs, inverters have 8 digit IDs. Tried just the last 4 no dice.

 

So now talking to the seller but it appears to be a known issue! Grrr.

 

Meanwhile using my quick and dirty monitor (ok my Kill-A-Watt) the system made just under 3 units on a rather dull and overcast day.

 

Is the modem strictly needed? Or just fun icing on the cake to monitor what's happening?

[Crossy]

9 hours ago, sometimewoodworker said:

Is the modem strictly needed? Or just fun icing on the cake to monitor what's happening?

 

Not strictly needed, but it should allow control of the output level of the inverters so I can turn off exporting on the days the meter reader may be noticing the meter going backwards. At the current power level there's no problem.

 

[tjo o tjim]

Is the modem zigbee or serial?  The software looks pretty cool from the screenshots I found, but your micro inverters look slightly different in the way they are labeled.  Did you just have the one label or were there stickers on the ports as well with the same (or different) number?

 

You could get out your arduino and set up a zigbee/serial sniffer, but if the software is validating for four digits you are kind of stuck...

[maxpower]

46 minutes ago, tjo o tjim said:

Is the modem zigbee or serial?

Zigbee is a communication protocol, serial is communication method.

 

[Crossy]

Well I've opened a dispute with the AliExpress seller for return and refund. The correct modem is +$200 over the one they sold me as compatible ????

 

Not entirely the seller's fault as the inverters look identical, just a different length of wireless ID number.

 

Meanwhile I've been speaking to the manufacturer, very helpful they are too, they are sending me the correct modem for $105 inc shipping.

 

Another dull day today produced 2.9 units.

 

[maxcorrigan]

14 hours ago, Crossy said:

 

Not strictly needed, but it should allow control of the output level of the inverters so I can turn off exporting on the days the meter reader may be noticing the meter going backwards. At the current power level there's no problem.

 

Does the meter reader tell you when he's coming, or do you keep a close eye on the spinning wheel and do a quick flip?

Interesting post by the way Crossy, as an old fabricating engineer it brought back a lot of memories, keep up the good work, want to see the finished job!

[Monomial]

Rather than worry about the complexity of batteries, why not do what many utilities are doing these days with their surplus power. Mine Bitcoin. That way, if you need the power, you have it available. If you don't, you store it as capital in a digital currency, which you then use to pay your electric bill. That way, you could size your system for peak load, and not have to worry about the complexity of storage.  The storage is entirely digital and scalable.

 

Doesn't help if you are worried about emergency power in case the grid goes down, but as a purely financial strategy it makes a lot of sense. 

[Naam]

10 hours ago, Monomial said:

why not do what many utilities are doing these days with their surplus power. Mine Bitcoin.

 

[SoonOh]

Thank You for sharing. Looking forward for updates and pictures. 

[VocalNeal]

I was thinking of using your spacer and rail system to add another layer of roof to emulate the Land Rover Safari roof of old. To reduce the absorbed heat of midday.

 

[Crossy]

Still waiting for the replacement modem.

 

There was actually some sun today, system made 4.3 units before the rain arrived.

[sfokevin]

On 9/4/2019 at 4:41 PM, Crossy said:

Well I've opened a dispute with the AliExpress seller for return and refund. The correct modem is +$200 over the one they sold me as compatible ????

 

Not entirely the seller's fault as the inverters look identical, just a different length of wireless ID number.

 

Meanwhile I've been speaking to the manufacturer, very helpful they are too, they are sending me the correct modem for $105 inc shipping.

 

Another dull day today produced 2.9 units.

 

Kudos!... That’s about 18 baht!... Monthly your saving 600 baht... That’s diner at Dukes!...

[sfokevin]

I was thinking of a similar setup with a main single inverter that would have a limiter to prevent the meter from turning backwards... Like this... 

 

https://www.lazada.co.th/products/2000-grid-tie-inverter-dc-45-90-v-pv-ac190v-260v-300w-6-1-i317922520-s600542057.html?spm=a2o4m.searchlist.list.35.2c742772yeVtsw&search=1

 

Here is a 1k watt version...

https://www.lazada.co.th/products/yh-1000w-mppt-solar-grid-tie-inverter-stackable-with-power-limiter-sensor-dc45-90v-solar-input-ac190v-260v-outputbattery-discharge-power-mode-i268396688-s420167630.html?spm=a2o4m.searchlist.list.56.46cf2772rNMBAc&search=1

[BritManToo]

On 9/3/2019 at 6:15 PM, Crossy said:

Meanwhile using my quick and dirty monitor (ok my Kill-A-Watt) the system made just under 3 units on a rather dull and overcast day.

 

My 1 panel made 8 units in 9 days.

Lots of rain and often cloudy this month.

[Crossy]

1 hour ago, BritManToo said:

My 1 panel made 8 units in 9 days.

 

Sounds about right.

 

We made 4.5 units on Sunday, there was actual sun for a while.

 

On the whole I'm reasonably happy, still not got the replacement modem ????