Australian Politics Forum - Renewable Energy (Spilt)

freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: Renewable Energy (Spilt) Reply #15 - Nov 7^th, 2008 at 1:31pm huh?
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muso

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Re: Renewable Energy (Spilt)
Reply #16 - Nov 7^th, 2008 at 1:44pm

Well for starters, take a look at the link that explains how the cooler works. All you need is a hot water supply.

The absorption cycle is driven by a thermal transfer fluid (hot water or glycol mixture) at 158 o F to 203 o F from solar thermal energy or other heat source and the condenser is cooled through a cooling tower. ....

The Yazaki absorption chiller or chiller-heater uses a solution of lithium bromide and water, under a vacuum, as the working fluid. Water is the refrigerant and lithium bromide, a nontoxic salt, is the absorbent. Refrigerant, liberated by heat from the solution, produces a refrigerating effect in the evaporator when cooling water is circulated through the condenser and absorber.

These are commercially built units. Now these actually use some electricity, but there is no theoretical need to do so. As it works by a thermal exchange system, efficiencies as high as 97% can be achieved.

By the way Sprint - the link shows a solar cooling system not solar hot water, but I'd still recommend solar hot water, especially if you have daughters or gf's staying over (when they get older).

Here's another excellent link to the topic of solar cooling:

http://www.climatemanagers.com/index.php?option=com_content&task=view&id=74&Item...

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yazaki-chiller-diagram.jpg (75 KB | 84 )

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freediver

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Re: Renewable Energy (Spilt)
Reply #17 - Nov 7^th, 2008 at 2:35pm

As it works by a thermal exchange system, efficiencies as high as 97% can be achieved.

97% of what?

Did you notice the scheme has a cooling water supply? So people would either have to leave the hose running constantly, or have a small lake in the backyard to act as a heat sink. It basically takes a convoluted, expensive way to cool your house and makes it even more convoluted by powering it from the sun instead of electricity. A simple evaporative cooler would use less water, less dangerous chemicals and cost a tiny fraction of this cumbersome machine.

muso wrote on Nov 7^th, 2008 at 1:28pm:

freediver wrote on Nov 7^th, 2008 at 1:25pm:

Retrofitting them can be expensive.

You don't even have to retrofit them. All you need is hot water.

Do you know what retrofitting means?

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muso

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Re: Renewable Energy (Spilt)
Reply #18 - Nov 8^th, 2008 at 6:08am

freediver wrote on Nov 7^th, 2008 at 2:35pm:

As it works by a thermal exchange system, efficiencies as high as 97% can be achieved.

97% of what?

Did you notice the scheme has a cooling water supply? So people would either have to leave the hose running constantly, or have a small lake in the backyard to act as a heat sink. It basically takes a convoluted, expensive way to cool your house and makes it even more convoluted by powering it from the sun instead of electricity. A simple evaporative cooler would use less water, less dangerous chemicals and cost a tiny fraction of this cumbersome machine.

muso wrote on Nov 7^th, 2008 at 1:28pm:

freediver wrote on Nov 7^th, 2008 at 1:25pm:

Retrofitting them can be expensive.

You don't even have to retrofit them. All you need is hot water.

Do you know what retrofitting means?

Feeding from a hot water tap would hardly count as retrofitting, although you'd need to feed the water back into the hot water system. For a gravity fed system, that's hardly a big deal.

The pictured unit is a large scale solar cooler designed for an office block or a warehouse. It can be used in reverse cycle mode to work as a heater during the winter months. Units like that have been installed all over Europe, and they don't use anything like as much water as an evaporative cooling system, because the cooling tower is tiny by comparison in this unit.

Of course the ideal situation is passive heating/ cooling systems, which just require a smarter building design, but this unit works well in older buildings.

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freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: Renewable Energy (Spilt) Reply #19 - Nov 8^th, 2008 at 9:00am Feeding from a hot water tap would hardly count as retrofitting, although you'd need to feed the water back into the hot water system. For a gravity fed system, that's hardly a big deal. I'm talking about retrofitting the solar collector to an existing roof. It is expensive. I have no idea what you are going on about.
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muso

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Re: Renewable Energy (Spilt)
Reply #20 - Nov 8^th, 2008 at 9:45am

What I mean is that if you have an existing solar hot water system, it's relatively easy to use the heat from the hot water (the excess capacity) to power a solar cooler in a domestic situation. (No extra solar collector required.)

You can either use electricity to pump the water around the coils, or use a direct gas turbine arrangement with no electricity required.

There are of course other possibilities, such as a heat pump for colder climates.

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tallowood Gold Member Offline Израиль Навсегда Posts: 8639 Gender:	Re: Renewable Energy (Spilt) Reply #21 - Nov 10^th, 2008 at 10:07pm "There is no escape" S = k_B ln Omega Entropy. The science of little stitches keeping big wounds closed.
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tallowood Gold Member Offline Израиль Навсегда Posts: 8639 Gender:	Re: Renewable Energy (Spilt) Reply #22 - Nov 14^th, 2008 at 12:52pm tallowood wrote on Nov 10^th, 2008 at 10:07pm: "There is no escape" S = k_B ln Omega Entropy. The science of little stitches keeping big wounds closed. Unless of course humans will break out of boundary of the close system. Outside of the square
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muso

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Re: Renewable Energy (Spilt)
Reply #23 - Nov 14^th, 2008 at 5:55pm

Mate, there is nothing controversial about Solar Cooling. Energy is conserved. We're not reinventing physics. You can reduce entropy by consuming energy. All refrigerators do that using electrical energy. In this case, the source of that energy is the sun. Many commercial units have been installed throughout Europe.

As far as this 'perpetual motion engine' is concerned, I'd like to know where it draws its energy from

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freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: Renewable Energy (Spilt) Reply #24 - Nov 14^th, 2008 at 6:02pm Can you give some references about their use in Europe?
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muso Gold Member Offline Posts: 13151 Gladstone, Queensland Gender:	Re: Renewable Energy (Spilt) Reply #25 - Nov 14^th, 2008 at 7:08pm freediver wrote on Nov 14^th, 2008 at 6:02pm: Can you give some references about their use in Europe? Sure: http://cat.inist.fr/?aModele=afficheN&cpsidt=3304132 http://www.sciencedaily.com/releases/2008/07/080714151427.htm Pdf: http://www.eurac.edu/NR/rdonlyres/E7869E44-95BB-4422-87C0-77E193248DBE/0/Europea...
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tallowood

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Re: Renewable Energy (Spilt)
Reply #26 - Nov 14^th, 2008 at 8:44pm

muso wrote on Nov 14^th, 2008 at 5:55pm:

Mate, there is nothing controversial about Solar Cooling. Energy is conserved. We're not reinventing physics. You can reduce entropy by consuming energy. All refrigerators do that using electrical energy. In this case, the source of that energy is the sun. Many commercial units have been installed throughout Europe.

As far as this 'perpetual motion engine' is concerned, I'd like to know where it draws its energy from

There was nothing controversial about diverting rivers flow and using irrigation till we reached boundary of limitation. The same will eventually happen with solar energy.
Fridges don't reduce entropy in environment only within own walls but extra energy dissipates outside increasing temperature around them. Harnessing solar will mean not consuming the energy but redirecting it and changing its form but doing so more energy will be consumed then saved. None of human build devices are 100% or more thermodynamic efficient.

However with all that if efficiency can be increase from say 90% to 91% it is worth doing providing that generation of energy and it's usage don't produce harmful wastes. In this way solar is preferable to burning carbon or to nuclear.

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muso

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Re: Renewable Energy (Spilt)
Reply #27 - Nov 15^th, 2008 at 6:17am

tallowood wrote on Nov 14^th, 2008 at 8:44pm:

There was nothing controversial about diverting rivers flow and using irrigation till we reached boundary of limitation. The same will eventually happen with solar energy.
Fridges don't reduce entropy in environment only within own walls but extra energy dissipates outside increasing temperature around them. Harnessing solar will mean not consuming the energy but redirecting it and changing its form but doing so more energy will be consumed then saved. None of human build devices are 100% or more thermodynamic efficient.

However with all that if efficiency can be increase from say 90% to 91% it is worth doing providing that generation of energy and it's usage don't produce harmful wastes. In this way solar is preferable to burning carbon or to nuclear.

Re your comments on Fridges, yeah it's always a local effect. I understand the Laws of Thermodynamics.

All refrigerative cooling diverts heat outside. In the scheme of things, that's not a big problem. As I'm sure you're aware, the greenhouse effect is all about increased solar heating of the planet, and this extra heat captured from the sun makes all other heat sources look insignificant by comparison.

As far as your comments on harmful wastes are concerned, tell me more. Full Life Cycle Analysis has already been carried out on these devices. It's an EU requirement for any renewable energy devices that are used as carbon offsets.

The efficiency is actually much higher than electrically powered refrigeration systems, especially if you take into account transmission and generation losses, electric motor efficiency losses etc.

Solar Cooling is a no-brainer in cases where passive cooling is not practicable - in other words existing buildings that can't be redesigned.

The only reason it hasn't been adopted in Australia yet is that we're a little behind the 8-ball in adopting it. However in terms of passive cooling and building design concepts, we're actually world leaders. We export the technology.

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freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: Renewable Energy (Spilt) Reply #28 - Nov 15^th, 2008 at 12:40pm The heat generated by burning fossil fuels (eg to run refridgerators) does not have a detectable impact on global temperature. It is the impact of the gasses released during the burning that is significant, as they hang around for a century or more and prevent the heat from the sun from radiating back out into space.
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muso

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Re: Renewable Energy (Spilt)
Reply #29 - Nov 15^th, 2008 at 7:02pm

freediver wrote on Nov 15^th, 2008 at 12:40pm:

The heat generated by burning fossil fuels (eg to run refridgerators) does not have a detectable impact on global temperature. It is the impact of the gasses released during the burning that is significant, as they hang around for a century or more and prevent the heat from the sun from radiating back out into space.

Yes, thank you. I probably explained that badly in my second paragraph, but that's it in a nutshell.

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