Mexstan

I am NOT an expert in this subject so need a bit of help. Actually, need LOTS of help and guidance.

The orphanage that I volunteer at is presently paying over US$1,100 a month in electrical bills. They are now looking at reducing that monthly cost with solar panels. My question for the more knowledgeable folks here is this;
It has been calculated that 128 solar panels are required to cover the energy usage there, but the initial cost is high. Yes, once they are installed, the monthly cost is dramatically reduced, but which is better, to just throw solar panels at the problem, or first take whatever steps can be done to reduce the consumption,such as LED lights, energy star appliances etc. After that, then recalculate how many panels will be required as the consumption will be reduced.
Is just adding more solar panels instead of reducing consumption putting the cart before the horse?

MikeyB

I would take the second approach in reducing the power consumption with more efficient equipment and other devices. Find out what the heavy power usage items are and start from there looking at more efficient means. For example is everything all electric? Like cooking appliances and water heaters? If so look to see if propane fuel is cheaper to consume for those items. More efficient AC/heater systems, replace incandescent lights with LED's, etc.

jrs_dodge_diesel

I would think so. Your first idea sounds more feasible. Definitely change your lighting out to compact florescents (CFL) and/or LED lighting. That alone will drop the usage a good bit, especially if you have a lot of incandescent lights. Then reassess the solar panels.

If you have a problem of people forgetting to turn off lights when leaving a room, you can install the motion detector switches.

Do you know what your electrical rate (kilowatt hour) that your utility is charging?

Mexstan

None of the buildings have heating or A/C. All the stoves are gas. There are numerous old style fridges, two very large walk in fridges (not sure if anything can be done about these) and of course lots of inefficient lights. Much of the water is solar heated with more to come. The rest is heated by gas. There are also assorted water pumps, but doubt if anything can be done about those either.

Don't know the rate, but will try to remember to look it up when I am out there on Monday.

SIXSLUG

It's the old fridges and probably a hot climate...

Solar panels are nice but expensive, and less efficient when really hot direct sunlight hits them, you will also be tending batteries if you aren't just adding power back into the local electric system...

I have changed all the bulbs in my house to LED except the girls bathroom, which are incandescent. When I watch the meter with those on it is spinning a lot faster than when a lot of the led's are on and the bathroom bulbs are off...

Mexstan

While it may sometimes get a bit hot here, it is actually a very moderate climate. In the sun it gets very hot, very quickly, but the shady areas are very comfortable. The fridges of course are indoors, so are all at a comfortable room temperature. The plan is not to use any batteries and a bi-directional meter.

j_martin

You are asking an engineering question and providing no information to make any engineering calculations.

Electrical usage (kilowatt hours per month) and/or cost per KWH.
Number, type, and wattages of lighting. Hours used.
Power consumption of each motor driven device.

Generally speaking, it takes a long time for solar panels to pay back their cost. I haven't been following closely, but here it was iffy even when US was paying a large percentage of the initial install cost. They are also in danger of weather induced damage, ESD (lightning) or winds.

A 100 watt lamp burning 10 hours a day consumes 30 KWH/month. At .10/KWH, that's $3.00 per month. A 1400 lux LED will consume between 1/5 to 1/7 as much power. Taking the higher number that's $0.60 per month, or $2.40 less, so pay back for a $15.00 LED lamp is about 6 months. These are all real numbers, actually on the high side.

Power factor correction on motors can gain 30% in efficiency pretty easily. That's a little trickier but worth while. You can get a Kill-O-Watt power measuring device for about $30 and track down the usage for each appliance. Then decide which to modify or replace.

If you have an old walk in cooler that's been converted to R134, you can gain a lot by re-converting to C12 (a propane-isobutane mix)

You may have gathered that I don't think throwing solar at the problem is the most economical solution. After power conservation measures at relatively low cost, the amount of equipment needed would be much less, so the solution is either conservation first, then solar, or conservation alone.

Mexstan

Thanks for the answers so far.

j_m, how 'bout coming down here for a day or two and giving us some sound advice?

SIXSLUG

J Martin has good advice.

I intended to say more direct sunlight as to relationship to the equator rather than hot. The angle of the sun may limit the efficiency of the panels if they get really hot from a more intense light angle than up here in the NW....I think they can be tilted though to increase efficiency. My solar guy moved back to Colorado back in '10 and I don't know any others around here

I asked my neighbor what his array cost and he's at 20K. Says his bill went from $60/month to about $18/month.....that's a long way to 20 grand!! He's proud of his commitment to reducing his carbon footprint though, so I guess it is worth it for him....His are mounted on a 7/12 pitch roof facing S-SW and due West.

Mexstan

One of the local companies who has been in the solar panel business for about 10 years has quoted the equivalent of US$86,236 (at today's ridiculous conversion rate) to install 17.5 kWp of panels (128), arrange for the bi-directional meter(s) etc etc. In other words, a complete system. They claim a return on the investment in 3.90 years.

The orphanage does not have this kind of money and relies 100% on donations. They have enough donated so far to obtain about 6% of the panels per this quote. The company is willing to do the initial installation and then add panels as the funds roll in. I am opposed to this and already told the director of the orphanage to FIRST address the root cause of their high energy consumption and after that step has been completed to reevaluate the situation and go for another quote.

j_martin

Twist my arm a bit. I have a daughter living at a mission near El Paso that needs visiting.

Mexstan

You have not seen your daughter for a while so a visit is long overdue. Right? Not sure how you would get from El Paso to here, but check out flights to Queretaro (QRO), Mexico City (MEX) or Leon (BJX). The best for us is QRO, then BJX. MEX is a 3.5 drive away.
If you are seriously considering a trip down here, send me a PM.

patdaly

One other thing, get someone to measure the Amperage drawn on each of the 110V legs. I don't know if the newer smart meters work the same way, but regular old meters spin based upon the highest leg, so if you have more load on one leg than another, you can be paying for more electricity than you are actually using. Once you balance the legs as good as possible, then my next advice would be to work as best you can to lower the total load as others have mentioned.

At that point you may well be able to start working towards a much smaller Solar setup to further reduce the cost.

Mexstan

Thanks for the tip. We have had balancing problems in the past, but new stuff has been added, so time to check again. This meter is a digital type.

AlpineRAM

I'll throw in my 2c...

I would also take a good look at all the refrigeration units you have.
A dusty condenser can increase energy consumption by more than 30%, so take care to keep them clean. Make sure that there is good air flow around the condenser and that the heat can get away from the device. Also take a good look at the door seals. Air entering there will kill efficiency.
For bigger split devices like the walk ins it can prove beneficial to go for a lower temperature during the cool of the night and let them warm up a little (not exceeding correct storage temp. for the goods) in the daytime.

As for solar- if you go for a much smaller array you can (should) go for something that will just carry your continuous consumption during the day, and never get into a situation where you sell electricity to the grid.
With a small array and a bit of control logic you can use EG 4kW average solar to power several walk in fridges by doing a "round robin" of turning them on when "free" energy is available.
If you want to go that route you will need to measure a lot before you start building.

Markus