Wow! Looks like impressive results can be had from passive solar! Thanks for the link.Pops wrote:A community kitchen in "Auroville , Tamil Nadu , India " has a fixed, very large parabolic dish ( multiple reflectors - 840 square metres ) built into the roof which generates steam ( 4000 Kg / day ) for the kitchen to cook with. This kitchen feeds several communities, approximately 10000 people.
About the lighting. I've seen a demonstration the system on a fair a while back. I believe it was by Schott Glasswerke from Germany. The idea is simple. You have a collector on the roof (basically a glass lens) and you send the light to wherever you want by glass-fiber.
The second problem is the light yield. If you have a collector as big as the roof of the building and 100% efficient, you'll be able to create the same light density inside as the natural light outside. However if your building has two floors the light has to be distributed over the two floors and your light density will halve, etc.
clv101 wrote:We were thinking about using narrow copper pipes and an array of lenses focusing the sun’s energy from a larger area down onto the pipes. Would these intermittent very hot spots on the pipe produce a more efficient system overall?
The difficulty of course is keeping the lens focused on the pipe as the sun moves through the day!
ExampleGiven wrote:A Tankless water heater should last 20 - 25 years and they can be repaired. My Gas Takagi tankless cost about 900. It costs about 25% less to run than a conventional water heater. The gas ones can deliver more gallons per minute that the electrics that I've read about.
Specop_007 wrote:ExampleGiven wrote:A Tankless water heater should last 20 - 25 years and they can be repaired. My Gas Takagi tankless cost about 900. It costs about 25% less to run than a conventional water heater. The gas ones can deliver more gallons per minute that the electrics that I've read about.
Exactly. I can get a gas hot water heater for what... 100 bucks on sale? I think mine was 150 or 200, right around there. The cheapest I found tankless was around 600 or so, and it'd be iffy on running much more then 1 appliance at a time. So, assuming 200 to 600, thats 400 bucks more for tankless. Its going to take you 20 years to recoup the difference in price!
gonin02 wrote:are high energy costs the reason these devices are popular in asia/europe?
until our energy prices reach that critical point it is not cost effective to own one in NA?Specop_007 wrote:ExampleGiven wrote:A Tankless water heater should last 20 - 25 years and they can be repaired. My Gas Takagi tankless cost about 900. It costs about 25% less to run than a conventional water heater. The gas ones can deliver more gallons per minute that the electrics that I've read about.
Exactly. I can get a gas hot water heater for what... 100 bucks on sale? I think mine was 150 or 200, right around there. The cheapest I found tankless was around 600 or so, and it'd be iffy on running much more then 1 appliance at a time. So, assuming 200 to 600, thats 400 bucks more for tankless. Its going to take you 20 years to recoup the difference in price!
Return to Conservation & Efficiency
Users browsing this forum: No registered users and 102 guests