The Spanish data quoted by Leigh is interesting re the 24 hour operation, but I would have thought that if some of the solar radiation was used to heat water for use during the night, that the power output during the day would be less. There is only a finite total energy per day, and if you average it so it lasts for 24 hours, the maximum rate of energy consumption (power) will have to be less. Cheers, John G.
----- Original Message ----- From: "Leigh Bunting" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, February 19, 2002 11:42 PM Subject: Re: [aus-soaring] Manmade Thermal? | Mike Cleaver wrote: | | > At 12:27 18-02-02 +1000, you wrote: | > | > Will it work in reverse at night due to katabatic flow down the chimney? | > | | Apparently -yes. But not in this way, see below: | | "A SOLAR power plant that generates electricity after sunset | sounds like a contradiction in terms, but the Spanish | experiment showed that the solar chimney has this rare talent. | Radiation passing through the collector heats not only the air | beneath it, but also the ground. This heat is released into the | air in the evening. | | As the air cools, the chimney becomes more sensitive to small | rises in temperature. And Schlaich's team found that by | covering the soil with more heat-absorbent materials, they | could make the prototype generate electricity for longer and | longer into the evening. Schlaich now proposes placing coils of | black plastic water-filled tubes under the collector. By pumping | water warmed during the day into an insulated store and then | returning it to the coils at night, he calculates that the plant | could be made to work at full capacity for 24 hours a day. | | Another idea tested in Spain was to use the outer portion of the | collector to grow food. Towards the rim, the air temperature is | not too much above ambient and the wind speed not too high. | This also means that people can work beneath much of the | collector while the plant is functioning. Maintenance near the | centre could be more of a problem. In a 100-megawatt plant, | the updraught would be about 15 metres a second (54 | kilometres an hour), which is bracing but not overpowering. | | The temperature, however, could reach a staggering 35 �C above | ambient." | | -- | Leigh Bunting | Colonel Light Gardens | South Australia | <Open Windows and let the bugs in> | | | | -- | * You are subscribed to the aus-soaring mailing list. | * To Unsubscribe: send email to [EMAIL PROTECTED] | * with "unsubscribe aus-soaring" in the body of the message | * or with "help" in the body of the message for more information. | | -- * You are subscribed to the aus-soaring mailing list. * To Unsubscribe: send email to [EMAIL PROTECTED] * with "unsubscribe aus-soaring" in the body of the message * or with "help" in the body of the message for more information.
