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Julian C Thong

David, is there any way you could post without all the colours and seeming like a salesman?

 

Just posting web addresses allows people interested to research. I automatically don't read your posts cos of the shpeel.

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david why dont you buy one and tell us how much you save and if it works after a few years we can all start buying them... but do hire a guard to protect your mirror or it will be for sale at the loca

It is very difficult to estimate energy costs over the next 20 years. I think the sensible system at the present cost point would only allow you to run power at an "emergency" level at night. I also t

'thebob', I think the KISS (Keep It Simple Stupid) principle needs to be applied here,   Liquid Salt, is indeed a method for storing heat, but not very practical for a home supply set up. Also not

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David_LivinginTalisay

David, the most efficient air conditioning systems are available now and have been for decades. Refrigerated Air Conditioners (RAC's)

Absorption refrigeration and Peltier systems were invented over a hundred years ago and are and always will be totally inefficient (Physics demands it)

 

All refrigeration systems (including refrigerated air cons) remove heat. This is why they are often called heat pumps.

There is no such thing as 'Cold'. Cold is not a measurable unit, heat is. Cold only exists relatively after heat is removed. So if we require something to be 'colder' we have to remove the heat. Heat removed is measured in watts of heat. (BTU's in the old days)

Removing this heat involves equipment using energy, usually electrical energy unfortunately also called watts (Lets say electrical watts)

Now the efficiency of the equipment used to remove the heat and cause the fridge or room to be colder can be measured and is quoted as the co-efficient factor. (Co-ef) The co-efficient factor is derived by dividing the amount of heat removed (watts of heat), by the energy used (electrical watts) by the equipment used to do the job. So if 1000 electrical watts are used to remove 2000 watts of heat the Co-ef would be 2 but if 2000 electrical watts are used to remove 1000 watts of heat the Co-ef would be only 0.5.

For example:

Say a room requires 2400 watts of heat per hour to be removed for it to be at a comfortable temperature.

A typical 1 HP Refrigerated air conditioner could provide this 2400 watts per hour of heat removal while using approx 800 per hour of electrical energy. It would therefore have a Co-ef of 3 which is typical for RAC's (2400 divided by 800)

Using an absorption system to do the same job would use approx three to five times more electrical energy than the RAC.

Using a Peltier system to do the same job would use approx eight to ten times more electrical energy than the RAC.

It is a no-brainer, these other forms of heat transfer are not just a little inefficient and perhaps could be improved, they have been around for over a hundred years and are many times less efficient than the common RAC.

 

I am a refrigeration engineer and in the past ten or so years there have been many, perhaps well intended, who are going to save the world by 'their' discovery. Only trouble is they are presenting ideas and principles, that were discarded decades ago, as their invention!!

With the huge amount of funding that is available and the gullibility of those distributing it, many of these dreamers end up well funded, at least until exposed. Then they disappear. The Spanish 'Solar power air conditioner' is a classic example. This is simply a refrigerated water chiller supplying an air handling unit.. Nothing new, there air millions of similar systems around the world, but no doubt some sucker organisation will fund these re-inventors.

Sorry David, there are no free lunches in the real world! Cheers.

 

 

'Ozepete'

My parents used to have an 'Electrolux Refridgerator' - this had no compressor, but used HEAT to power such Absorption Refrigerator (Electric heating element in this case)

Absorption refrigerator

From Wikipedia, the free encyclopedia

An absorption refrigerator is a refrigerator that uses a heat source (e.g., solar, kerosene-fueled flame) to provide the energy needed to drive the cooling system. Absorption refrigerators are a popular alternative to regular compressor refrigerators where electricity is unreliable, costly, or unavailable, where noise from the compressor is problematic, or where surplus heat is available (e.g., from turbine exhausts or industrial processes). For example, absorption refrigerators powered by heat from the combustion of liquefied petroleum gas are often used for food storage in recreational vehicles.

 

Both absorption and compressor refrigerators use a refrigerant with a very low boiling point (less than 0 °F/−18 °C). In both types, when this refrigerant evaporates (boils), it takes some heat away with it, providing the cooling effect. The main difference between the two types is the way the refrigerant is changed from a gas back into a liquid so that the cycle can repeat. An absorption refrigerator changes the gas back into a liquid using a different method that needs only heat, and has no moving parts. In comparison, a compressor refrigerator uses an electrically-powered compressor to increase the pressure on the gas, and then condenses the hot high pressure gas back to a liquid by heat exchange with a coolant (usually air). Once the high pressure gas has cooled, it passes through a pressure release valve which drops the refrigerant temperature to below freezing. The other difference between the two types is the refrigerant used. Compressor refrigerators typically use an HCFC or HFC, while absorption refrigerators typically use ammonia.

 

The standard for the absorption refrigerator is given by the ANSI/AHRI standard 560-2000[1].

 

How does a gas-powered fridge actually work?

 

The gas-powered fridge was invented by Baltzar von Platen and Carl Munters, from the Royal Institute of Technology in Stockholm, in 1922. You can read about it here on the Electrolux website. Later Albert Einstein and Leo Szilard patented it a variant of the idea.

 

You can read a thorough descrition of these fridges in David Grant-Taylor's Ph.D. thesis .

 

The fridge has no moving parts and is powered by a small flame or heat-source. It uses a working fluid which is a mixture of ammonia and water. The space in the pipes is filled with hydrogen and the whole thing is pressurised and sealed.

 

electrolux.jpg

 

There are three interlinked circuits in this fridge. Ammonia circulates round the outer loop B-T1-T2-T3-T7-C-P-Q-P-B. Hydrogen circulates around the left loop C-T4-T3-T7-C. A dilute ammonia solution in water circulates round the lower loop B-T4-C-P-Q-P-B. The actual cooling occurs at the evaporator, T3, (which is inside the ice box of the fridge) where pure liquid ammonia evaporates in a light breeze of hydrogen, removing latent heat and producing a cooling effect.

 

The main ammonia cycle works like this: The boiler, B, contains a solution of ammonia in water. The heat from the flame evaporates the ammonia and some water and these vapours flow up into the condensor T1. This has cooling fins on the outside and is designed so that the water condenses out and runs back into the boiler while the pure ammonia vapour continues to the second condensor, T2. The pure ammonia collects in U from where it dribbles into the evaporator T3 which is in the ice box. Some of the ammonia dribbling down T3 evaporates because there is a continuous flow of hydrogen blowing past (see below). The evaporation creates the cooling effect. The heavy ammonia vapour and remaining ammonia liquid falls down T7 into the reservoir, C.

 

The hydrogen cycle works like this: A steady trickle of weak ammonia solution flows from the boiler, B, into the absorber, T4. This dissolves the ammonia vapour coming up from C and allows pure hydrogen to circulate up T6. The hydrogen is drawn up as the denser ammonia vapour and hydrogen mixture falls down inside T7. This hydrogen-pump creates the continuous flow of hydrogen that evaporates the ammonia in T3, cooling the fridge.

 

The dilute ammonia cycle works like this: From the reservoir, C, the rich liquid flows along a pipe, P, to a coil where it is heated, Q. Vapour travels up the vertical part of P and into the boiler, B. This keeps the level in the boiler high enough that the diulte ammonia solution flows up T5 and into the top of T4. This solution, running down T4, attracts the ammonia vapour out of the upgoing hydrogen. The solution is dilute because it has come from the bottom of the boiler where the denser, weak solution, sinks. Ammonia solution in water is less dense than water.

 

Now how on earth did anyone manage to invent something as clever as that?

 

Well, Einstein was a clever guy of course.....

 

 

 

 

Amazing That Electolux, designed, produced, and successfully sold, such an old design, that had no compressor, just a heat source, so amazingly silent in operation!

 

576px-Absorption_fridge.jpg

 

 

What is Electrolux Refrigerators

 

The most popular type of refrigerator which employs vapor absorption system is the electrolux refrigerator. It works on three fluid absorption system. A three fluid system employs a refrigerant, a solvent and an inert gas, and eliminate the aqua pump from the system thus making it completely free from moving parts.

 

The whole plant is separated into two section, the "low side" in which evaporation is effected by a steadily maintained low pressure and a high side" where the reclamation of the refrigerant in a liquid state is achieved under the influence of high pressure and heat.

 

Ammonia gas coming out of the boiler is passed through the rectifier or water separator which is provided between the boiler and the condenser so as to prevent the entry of any water vapour into the evaporator where it would freeze and stroke the machine. After this the gas is liquefied in the condenser from where it gravities to a U-tube gas seal containing liquid ammonia and then enters the evaporator. The whole plant is charged to a pressure of about 1 kg/cm square. The evaporator contains hydrogen at a pressure of 12 kg/cm square, Therefore as soon as ammonia enters the evaporator it pressure falls to 2 kgf/cm-square according to Dalton law of partial pressure keeping the same total pressure and corresponding temperature being about -18C. Due to low temperature; ammonia evaporates taking its heat from the refrigerated space and thus produce cooling effect.

 

The heavy mixture of ammonia vapour and hydrogen then passes into the absorber where it met water coming from the boiler. In the absorber ammonia is absorbed in water shiest hydrogen rises up and returns to the evaporator. The strong solution of ammonia issuing from the absorber is preheated in the inter charger, and in urn dilute solution on its way to the absorber, is cooled therefore absorption is accelerated.

 

Since the total pressure on the high and low sides are equal so the only pressure head against which the liquid is to be forced so that it may enter the boiler is"h".The necessary pumping action to overcome this head is achieved by applying a small amount of heat to the coil a t"A". This way the ammonia vapour continuously circulates and thus produces cold in the evaporator.

 

 

This year, Electrolux is celebrating its 90th anniversary.

The ambition for the company has always been to provide innovations and products that improve people's quality of life.

 

The D fridge – the end of explosions (1925)

 

The first Electrolux refrigerator was a cooling machine that converted heat to cold through a process of absorption, the Model D fridge could run on electricity, gas or kerosene. It also required a water source and a drain. The cooling medium was ammonia, which unlike other cooling substances used at the time was not prone to explode under pressure.

 

Baltzar von Platen and Carl Munters, two very well known Swedish engineers, developed the Model D process during their studies at the Royal Institute of Technology in Stockholm. Electrolux president Axel Wenner-Gren subsequently made an offer and based the whole of Electrolux' future on the success of this new refrigerator.

 

 

The air fridge – refrigerators enter middle-class households (1931)

 

Refrigeration technology was further developed and refined in the 1930s. The problem with the previous Model D fridge was that it needed a power source as well as running water to function. The new air fridges, the L1 stand-alone unit for example, used air to cool the ammonia, thereby making it much more flexible and independent of a source of water. By the late 1930s, a refrigerator was a standard piece of equipment in most middle-class households.

 

 

The City Box freezer – compact living a la 1950s (1956)

 

The most important trend of the 1950s was in the food storage segment. Refrigerators rapidly grew larger, and for reasons of operating economy were gradually forced to shift to compressor operation. The result of the transition was apparent by the late 1950s, when the brand new tall refrigerators were introduced. They were combined appliances with refrigerator, freezer and cool compartments. The increasingly fast-growing deep-freeze industry created demand for freezers, and Electrolux introduced its first in 1956, the City Box.

 

The SP 111 refrigerator – a substitute of the cellar (1959)

 

Electrolux learnt that consumers wanted a cellar or pantry-type cabinet in their new apartments. Since there wasn't space for one in the new modern apartments, it was instead incorporated into the fridge. Therefore, the SP 111 included a refrigerator at shoulder height, and underneath a cooled cabinet for storing items like jams and juices – items that traditionally would be stored in a cellar.

 

 

Hard to imagine this would still be selling if so grossly inefficient as 'Ozepete' suggests with "Absorption refrigeration and Peltier systems were invented over a hundred years ago and are and always will be totally inefficient (Physics demands it)"

 

We had a small Refrigerator that we used with our Trailer Tent in the UK (and on a Trip to France once). One could run it off the Mains Electric the night before to get it nice and cold and make the ice cubes, run it off the Car Alternator, charging an Auxiliary 12V Battery, and run it off Propane Gas at the camp site. Efficient or Not, is was damn convenient!

 

Say what you like, if one replaces such Heat Source with FREE Power from the SUN, what does it matter in terms of energy conversion efficiency if all those Megawatts of the Suns Heat Energy cost you Nothing (except the cost of the equipment to capture and convert that captured Heat energy to water of at least 190)

Edited by David_LivinginTalisay
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Stranded Shipscook

A very good thread, aletrnative power is the future, no doubt about it.

 

more important arguments which are mostly overlooked in the debate what is cheaper :

 

The Public Energy costs in the near and distant future WILL not get Lower !!!

 

And even when national or private big energy suppliers will bring the "Green" power in future, they still will charge more. Mainly the argument would be the large investments they have to make.

 

So when u invest some money now, you got a guaranteed price for the next 25 years or so. Not much saving ?

 

Those who can remember, how much did a liter of fuel sold in the 80ties? or a Kw/h

 

convert the examples of Kw/h price from that time and imagine you had that equipment in those years, yes, leave the purchase price without theoretical adjustment due to inflation rate.

 

The savings then are enourmous.

 

From my own 2 Solarcells on the Yacht i know that they constantly put power out, rain (60%) or shine (100%)

 

Here in the Philippines mostly too much, the regulator burned through and the batteries boiled ! Siemens send me a new and Tropic adjusted regulator for free from Germany.

 

i jst wish i had a million peso cash, then i would go for it right away !

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aletrnative power is the future, no doubt about it.

 

 

Whilst I agree, there is more rubbish talked about solar/alternative energy than almost anythng else. Also, many of the claims made by manufacturers and dealers are, to say the least, optimistic.

 

I built my first heat engine in the early 60's, and have built many since. (In fact, I have one, a Heinrici, half-built on the bench right now.)

By the late 60's I had a solar powered engine that ran a water pump. OK, only a small pump it is true, but the solar dish was only the size of a dustbin lid... which it was.

 

In 1979 I moved house and built an experimental solar powered heating system for my workshop.

 

Whilst none of this makes me an expert, it does mean that I can look critically at the claims that are made.

Some of which are dubious.

Check before you buy.

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I've looked into harnessing solar energy both for electricity as well as providing hot water. Quite frankly, the payback period is far too long for us here in the Philippines - and that's if you can locally obtain everything you need and, from my research, you can't.

 

If you have a look at the Home Depot web site (and there is a Home Depot on Guam), you'll find a solar panel kit suitable as the sole power generating source for a typical family home. That costs around 480,000 Pesos for the twelve panels and two controllers but does not include mounting hardware or fixings. Nor does it include the (ideally) 24 deep-cycle batteries nor the full sine-wave inverter you'll also need. The only deep-cycle batteries I've located here are made by Motolite and cost in excess of 8,000 Pesos each - so an additional 192,000 Pesos. I've not been able to source a suitable inverter here but you could obtain one from Europe for around 200,000 (excluding import duties). (A somewhat cheaper alternative would be to use a modified sine-wave inverter but that's not recommended where electronics or motors are to be powered.) So an investment of 872,000+ would be required. Now my last electricity bill in Cebu was 4,500 Pesos, so the payback time would be about 194 months - or 16 years and 2 months.

 

There are, however, two things not factored-in to the calculation above. Firstly that VECO bills will rise during that period but by how much, one can not say for sure. The second is that you will have to start replacing batteries at three-yearly intervals at least (and possibly more frequently than that) and, of course, the cost per battery will increase also. I've also not factored-in import duties but I estimate it would take at least 25 years before the power generated would be "free". Wellll.... not quite: the other day I met a "visiting fireman" from a German Company a division of which is involved in solar energy. He told me that, at best solar panels are 60% efficient but the real kicker is that they degrade over time and have a maximum rated life of less than 20 years. So, in truth, there is no payback.

 

Now for solar-powered hot water. If you go down to Citi Hardware you'll find a display of "Solar Powered Hot Water Heaters" manufactured by Suntec, a Chinese company; the unit I saw costs 36,000 Pesos and is mounted on a steel frame designed to be put somewhere at ground level where it will get full sun - in a city that could be a problem. Unfortunately the descriptive name is a bit misleading since these are most definitely NOT designed to be connected directly to the household plumbing - even though the "sales assistants" will try to tell you otherwise. If you were to attempt to connect it to the plumbing, one or both of the following would happen - the water pressure will fracture one or more of the evacuated glass collection tubes or you'll melt the plastic pipework of your house - these things can heat water to over 90 degrees Celsius and the plastic pipework I've seen here is rated at less than half that. Rather, these devices are designed to be connected to the coil that is inside an indirect hot water cylinder via a low pressure recirculating pump (of the type typically found on most British central heating systems). Are such cylinders available? Of course not! From what I've read about these systems, they really should be connected using copper (the heat exchanger is manufactured from copper and connecting copper directly to steel is not a good idea) - and good luck finding decent copper tube of the right size and suitable fittings here.

 

If one were to import the copper indirect cylinder, insulating jacket, recirculating pump, thermostat, copper tube and fittings at a likely cost of another 50,000 or so, that makes for an exceedingly expensive hot water system. A better bet is an imported US-made electric water heater/storage tank, the biggest of which is a mere 28,000 Pesos (at Citi Hardware). Bear in mind that an electric water heater only uses electricity when it's heating water, the Suntec system uses it all the time.

 

I would dearly love to be off-grid but it really isn't worth the cost. Besides, here in Davao, electricity is cheaper and we enjoy a considerably more stable supply so I'll let Davao Light generate and distribute what I need and save myself a stack of cash.

 

 

 

 

 

Mark

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Ozepete

David's quote:

Hard to imagine this would still be selling if so grossly inefficient as 'Ozepete' suggests with "Absorption refrigeration and Peltier systems were invented over a hundred years ago and are and always will be totally inefficient (Physics demands it)"

 

Dave, these are 'Absorption' systems that you displayed and they are grossly inefficient compared to compressor refrigerators. The still sell these world wide because they can also operate from gas (or some with kerosene) and therefore suit where no electrical power source is constantly available. They do have a small market position. They suit caravans, remote camps etc. Traditional absorption fridges also have narrower operating ability. That is they don't work well, if at all, in high ambients. (Above 35c) Just when you need them most, they sit there using heaps of power and deliver bugger all cooling... just ask a caravaner in Central Oz during summer!

Likewise peltier systems are still sold. These are usually the cheap lunch box sized coolers. They are ok for providing temperatures about ambient less 25c but chew up huge amounts of power. These are very cheap to buy and suitable if you can put up with food / drinks at +15c on a 40c day!! But again they are hugely inefficient but ok for keeping a sandwich or two cool but thats about all! (A US green organisation provided huge funding for a mob of tricksters who had them convinced they could refrigerate milk from Indian dairy-farms with this method!!)

We would all like to have less power hungry appliances and power for free, but unfortunately it ain't going to happen with absorption or peltier system refrigeration. Although there will be a lot getting very rich by presenting 'amazing' breakthroughs to well meaning investors, and that's what really pisses me off. Sooner or later there will be some real major advances but funding them will be difficult because of these frauds.

At our company we have been doing a lot of research into the application of eutectic systems to todays refrigeration requirements. (Eutectic refrigeration is not new. It involves freezing a medium through it's phase change point so as to store thermal energy while power is abundant, to be used later) This technology has huge potential, particularly where power is erratic or limited, and is being successfully used in the boat refrigeration systems we manufacture in Oz.

Cheers.

 

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David_LivinginTalisay

Solar AC Unit Employing Solar Absorption Chiller Technology

 

 

 

Les Hamasaki, developer of a ten ton solar absorption chiller air conditioner system, at Debs Park Audubon Environmental Center in Los Angeles, explains that his AC unit uses lithium bromide which is safe and not dangerous to the environment like conventional AC units which use ozone-destroying CFCs. His solar AC unit utilizes solar absorption chiller thermal heat pipe technology, which has been around some time, and is easy and cost effective to produce.

 

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Stranded Shipscook
aletrnative power is the future, no doubt about it.

 

 

Whilst I agree, there is more rubbish talked about solar/alternative energy than almost anythng else. Also, many of the claims made by manufacturers and dealers are, to say the least, optimistic.

 

I built my first heat engine in the early 60's, and have built many since. (In fact, I have one, a Heinrici, half-built on the bench right now.)

By the late 60's I had a solar powered engine that ran a water pump. OK, only a small pump it is true, but the solar dish was only the size of a dustbin lid... which it was.

 

In 1979 I moved house and built an experimental solar powered heating system for my workshop.

 

Whilst none of this makes me an expert, it does mean that I can look critically at the claims that are made.

Some of which are dubious.

Check before you buy.

 

Could you kindly share a link or something, i want to fiddle around a bit too with alternative staff to build.

Thanks in advance

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Guenther, as it was pre-internet, most are in magazines, predominantly Model Engineer mag.

 

However, whilst in the Philippines once, I did build a small heat engine from scrap with only hand tools. It ran on coconut husks or even when placed on the edge of a cooking fire, and drove a fan that cooled the air down a bit, or at least, circulated it. (I hoped the locals would be impressed and try to do the same thing, but, sadly, not.)

 

 

Send me a PM with your email and I'll see what I have that I can copy and send you.

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  • 3 weeks later...

Personally as opposed to a complete system, I would be quite happy with a reasonable cost standby system to run fans lights fridge during brownouts!

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In the US, the Real Goods people (http://www.realgoods.com/home.do) have been in business for 30 years. They sell a wide range of products from many manufactures and cover the entire spectrum of off-grid life. Their Solar Living Source-book (http://www.realgoods...ok-realgoods.do) is a compendium of all approaches to off-gris and discusses much more than just solar power that tales after the original Whole Earth Catalog. It includes extensive introductions, basic engineering, and products that range from solar powered flashlights to giant systems that can feed American power hungry lifestyles. They also have low wattage appliances, solar water heating, and also a solid array of 12-volt products.

 

This thread was begun as a pitch for a specific product that seems over-priced and under-performing when compared to the market place.

 

The Source-book also included all the algorithms for calculating cost/benefits that both amortize initial investment and ongoing maintenance costs. Batteries are, indeed, needed and are a large part of the expenses and require good care and feeding. RealGoods generally encourages people to start small and not invest in a large system until you know what you're doing. They recommend that one start with golfcart batteries which are designed for deep cycle charging. Marine batteries also have deep cycling properties but are also usually designed to provide engine starting voltage thus spending both weight and cost for features not needed..

 

To deal with power looses here in my Maryland suburb (had a 4 day outage 5 years ago and 4-8 hour ones now in bad storms) I use a product I bought from RealGoods , the Xantrex Power 1500. It is an integrated deep cycle battery, 1300 watt inverter, and charger built onto a cart. It does a great job during brownouts keeping my fish tanks going and a few other things. Xantrex is a well respected company that has been in the alternate energy business for a long time, with inverters, to change 12v DC into 120 (or 2xx) AC. I also have an old home computer UPS that I keep charged as well. One could build the equivalent of my system for less by cobbling together a couple golf cart batteries, a charger, and a low end inverted. One should also beware that most inverters do not produce a clean sinewave. This is fine for most electrical products but can screw up the sound in decent audio gear.

 

I am curious if anyone knows of the use of solar hot water heating in the Ph. Solar water heaters can be made much more easily than solar electrical systems and only require basic plumbing and carpentry skills to set up.

 

My biggest advice is buyer beware. There are no silver bullets and even the simplest solar systems require knowledgeable users and basic engineering to avoid disappointment and wasted money. Also these systems, mishandled, can easily kill you. Batteries can leak explosive gas and very dangerous electrical arcs can be created if mishandled. The kind of "just buy this one thing and you will be all set" advertising, like that which began this thread, are at the least misleading. The system as originally described, without batteries, would only be useful in the Phil when the sun was shining - one would need to be hooked to the grid if one wanted any power at night or in cloudy weather. I own land in the Utah desert, where the sun really does shine bright most days, but I would not trust my someday home there to solar alone. Interconnecting a home solar setup to your house wiring is certainly possible (and again the Real Goods Source-book discusses how at length) but should only be installed by a competent electrician. Many experienced off-grid people in the US recommend having a diesel generator for backup to the solar system. Gas and propane generators are also available. Real Goods also has freezers and refrigerators that run directly from propane or other natural gas.

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Davaoeno

David_LivinginTalisay, on 31 October 2010 - 11:05 AM, said:Charging batteries from this AC power and then drawing power from inverters connected to these batteries (or directly for LED lighting or Florescent tubes running of 12V DC modules), is probably the only practical solution for power when the sun is not shining.

 

 

 

cdpino posted: To deal with power looses here in my Maryland suburb (had a 4 day outage 5 years ago and 4-8 hour ones now in bad storms) I use a product I bought from RealGoods , the Xantrex Power 1500. It is an integrated deep cycle battery, 1300 watt inverter, and charger built onto a cart. It does a great job during brownouts keeping my fish tanks going and a few other things. Xantrex is a well respected company that has been in the alternate energy business for a long time, with inverters, to change 12v DC into 120 (or 2xx) AC. I also have an old home computer UPS that I keep charged as well. One could build the equivalent of my system for less by cobbling together a couple golf cart batteries, a charger, and a low end inverted. One should also beware that most inverters do not produce a clean sinewave. This is fine for most electrical products but can screw up the sound in decent audio gear.

 

I used to have a house in the Dominican Republic. Every decent house there, and every business, had a bank of car batteries - 6-12] and an inverter because there is a brown out every day in the DR [ if there was a day w/o a brown out i missed it ! ] But here in the Philippines I have not seen one similar set up- even in expensive houses. Can someone please explain to me why such systems arent used here please? I was thinking of putting such system in my house here in Davao

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Ozepete

David_LivinginTalisay, on 31 October 2010 - 11:05 AM, said:Charging batteries from this AC power and then drawing power from inverters connected to these batteries (or directly for LED lighting or Florescent tubes running of 12V DC modules), is probably the only practical solution for power when the sun is not shining.

 

 

 

cdpino posted: To deal with power looses here in my Maryland suburb (had a 4 day outage 5 years ago and 4-8 hour ones now in bad storms) I use a product I bought from RealGoods , the Xantrex Power 1500. It is an integrated deep cycle battery, 1300 watt inverter, and charger built onto a cart. It does a great job during brownouts keeping my fish tanks going and a few other things. Xantrex is a well respected company that has been in the alternate energy business for a long time, with inverters, to change 12v DC into 120 (or 2xx) AC. I also have an old home computer UPS that I keep charged as well. One could build the equivalent of my system for less by cobbling together a couple golf cart batteries, a charger, and a low end inverted. One should also beware that most inverters do not produce a clean sinewave. This is fine for most electrical products but can screw up the sound in decent audio gear.

 

I used to have a house in the Dominican Republic. Every decent house there, and every business, had a bank of car batteries - 6-12] and an inverter because there is a brown out every day in the DR [ if there was a day w/o a brown out i missed it ! ] But here in the Philippines I have not seen one similar set up- even in expensive houses. Can someone please explain to me why such systems arent used here please? I was thinking of putting such system in my house here in Davao

What you refer to here is a most practical power back up system possible.

Have a battery bank (one or many in parallel) which is connected to a constant 3 stage charger. A pure sine-wane inverter then converts the battery DC power into the required 220 VAC an 60 hertz. The power from the inverter can then be connected to appliances that are essential.

 

BUT: You first must do some homework...

1. Identify the appliances that you need to power up at any one *time during brownouts then add up their consumption in watts (Usually on the appliance tag) *You may opt to run them sequentially, say the fridge first until it is satisfied then others etc. to keep this figure down.

2. This figure indicates the load on the inverter. Next the inverter should be rated at no more than 50% duty so double the wattage figure. To start induction motors like fridges / freezers etc the inverter must be grossly over-sized further or have surge capability of >300% of it's nominal rating. So lets say the fridge needs 300 watts (Typical cyclic defrost small fridge) and other essentials bring the total to say 500 watts. A 1000 watt (1 Kw) pure sine wave inverter with some surge capacity would suit. (Avoid any except pure sine-wave)

3.. Now the battery bank to supply the inverter. Using the example above, to power an inverter supplying 500 watts at 220 VAC from 12 VDC will require 41.6 amps at 12 VDC theoretically. Theoretically because there are are issues that alter the equation. Firstly the inverter will 'waste about 20%' , secondly the batteries will and should only be required to supply 50% of their rated storage capacity. So now the equation is like this: (41.6 amps x 1.25) x 2 = 104 Amperes. Therefore you would require a battery with about 100 amps rated capacity at 12 VDC to provide 500 watts of 220 VAC for one hour via an inverter.

4. The charger to re-supply the battery(s) needs to be rated so as to be able to replace the battery energy consumed before the next brown out. It should also suit the battery(s).

 

Or: You go buy a little 4 stroke 1000 watt inverter genie (!Kw) and save a lot of stuffing around. And unlike all the other options, the genie doesn't cost a mint or run out of puff!

 

Cheers..

Edited by Ozepete
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Davaoeno

Thanks Ozepete- can you tell me why that system isnt used here- when it is almost universal in the DR ? [ My assumption was that filipinos figure that if they dont think about or prepare for brownouts then maybe they wont happen ! But then i'm a cynic ]

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David_LivinginTalisay

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Edited by David_LivinginTalisay
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