Return-Path: Received: from rly-df04.mx.aol.com (rly-df04.mail.aol.com [172.19.156.17]) by air-df03.mail.aol.com (v123.3) with ESMTP id MAILINDF032-54649b42b652cc; Sun, 08 Mar 2009 16:32:59 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-df04.mx.aol.com (v123.3) with ESMTP id MAILRELAYINDF045-54649b42b652cc; Sun, 08 Mar 2009 16:32:39 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LgPfc-00024Z-66 for rs_out_1@blacksheep.org; Sun, 08 Mar 2009 20:32:24 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LgPfb-00024Q-Ou for rsgb_lf_group@blacksheep.org; Sun, 08 Mar 2009 20:32:23 +0000 Received: from mhost01h.leeds.ac.uk ([129.11.77.238]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LgPfb-0001Kj-1c for rsgb_lf_group@blacksheep.org; Sun, 08 Mar 2009 20:32:23 +0000 Received: from APOLLO1.ds.leeds.ac.uk (apollo1.leeds.ac.uk [129.11.5.4]) by mhost01h.leeds.ac.uk (8.14.3/8.14.3) with ESMTP id n28KVU1R004012 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT) for ; Sun, 8 Mar 2009 20:31:31 GMT Received: from dexbr1.ds.leeds.ac.uk (129.11.76.19) by APOLLO1.ds.leeds.ac.uk (129.11.5.4) with Microsoft SMTP Server id 8.1.311.2; Sun, 8 Mar 2009 20:32:16 +0000 Received: from HERMES4.ds.leeds.ac.uk ([129.11.5.130]) by dexbr1.ds.leeds.ac.uk with Microsoft SMTPSVC(6.0.3790.3959); Sun, 8 Mar 2009 20:32:14 +0000 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-Class: urn:content-classes:message MIME-Version: 1.0 Date: Sun, 8 Mar 2009 20:32:15 +0000 Message-ID: <731EB49F88B309428FFDDD2423F810E4B90C1C@HERMES4.ds.leeds.ac.uk> X-MS-Has-Attach: X-MS-TNEF-Correlator: <731EB49F88B309428FFDDD2423F810E4B90C1C@HERMES4.ds.leeds.ac.uk> Thread-Topic: Re: energy saving bulbs Thread-Index: AcmgBQlcGnSesynkRq62WV9GOYbLuQAI+pBo References: <1794381892.23372.1236524009509.JavaMail.mail@webmail03> <007f01c9a004$97057380$0900a8c0@AM> From: Chris Trayner To: X-OriginalArrivalTime: 08 Mar 2009 20:32:14.0694 (UTC) FILETIME=[F76DC060:01C9A02C] X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Content-Type: multipart/mixed; boundary="----_=_NextPart_001_01C9A02C.F81A4D68" Subject: LF: RE: Re: energy saving bulbs X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) ------_=_NextPart_001_01C9A02C.F81A4D68 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear All, Thanks, Alan, for your thoughts. > The tale that filament lamps are inefficient is a myth !! All the energy f= ed to the bulb is converted into radiation ! some is light and some is heat.....a CLF just produces less heat and more light and more polution! Well, in a sense you're right: efficiency is defined as (energy out) / (ener= gy in), and the conservation of energy principle implies that (in the steady= state) everything is 100% efficient ;-) In practice, by efficiency one means (wanted energy out) / (energy in), and=20= when you turn on a lamp you're not necessarily cold. In engineering terms it= 's better to decouple the things and have a lamp produce just light.=20 - Electricity is generated at something like 1/3 efficiency overall, and usi= ng fuels to generate heat directly is better. - The idea that waste heat can be used is relevant in cold climates, but pre= sumably less so nearer the equator. I also wonder whether these discussions may be useful only for a limited tim= e. I get the impression that LED room lighting may be starting to replace ot= her forms. Is this right? How does its efficiency compare with other forms?=20= Opinions, anyone? If LED room lighting does come in, it raises new problems of interference re= levant to LF. One thinks of LEDs as being innocent DC devices fed via a resi= stor. But modern designs often turn them on and off at frequencies in the kH= z range, generating harmonics going into the lower radio bands. This has bee= n known for some time in the cave radio community, where 87kHz is the most c= ommonly used band. The Cave Radio Journal has also documented interference w= ith 2m and 70cm amateur band handhelds. This can work both ways - if I speak= into a PMR446 radio it quenches my LED helmet lamp - the Empire strikes bac= k! Cave radio experience is that interference from LED lamps is very short rang= e, but these lamps are driven from local batteries. Will mains-driven ones r= adiate from the wiring? Do vehicle LEDs cause interference? Does anyone have= any experience of this? 73, Chris G4OKW ----------------------------- Dr Chris Trayner School of Electronic & Electrical Engineering, The University of Leeds, Leeds LS2 9JT, United Kingdom Tel: +44 113 34 32053 Fax: +44 113 34 32032 ------_=_NextPart_001_01C9A02C.F81A4D68 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: base64 eJ8+IhEUAQaQCAAEAAAAAAABAAEAAQeQBgAIAAAA5AQAAAAAAADoAAEIgAcAGAAAAElQTS5N aWNyb3NvZnQgTWFpbC5Ob3RlADEIAQ2ABAACAAAAAgACAAEEgAEAHAAAAFJFOiBSZTogZW5l cmd5IHNhdmluZyBidWxicwBsCQEFgAMADgAAANkHAwAIABQAIAAPAAAALgEBIIADAA4AAADZ BwMACAAUACAADwAAAC4BAQmAAQAhAAAAMUIwNTVFRkFDQ0E3OUE0OTg3RTVFMzM5RUM2NzRC MjEAWQcBA5AGAAwOAAA5AAAAAwAmAAAAAAADADYAAAAAAEAAOQBoTRr4LKDJAR4APQABAAAA BQAAAFJFOiAAAAAAAgFHAAEAAAA5AAAAYz11czthPSA7cD1Vbml2ZXJzaXR5IG9mIExlO2w9 SEVSTUVTNC0wOTAzMDgyMDMyMTVaLTE2MTIAAAAAHgBJAAEAAAAcAAAATEY6IFJlOiBlbmVy Z3kgc2F2aW5nIGJ1bGJzAEAATgAAj85zBKDJAR4AWgABAAAAIwAAAG93bmVyLXJzZ2JfbGZf 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