I had a thermocouple from an appliance lying around in the garage and I decided that it would be a good idea to experiment with it.\u00a0 It was a used one, but I don’t know what it was from; maybe a water heater.\u00a0 But a long time ago I had cut off the end that goes into the thermostat, so all that was left was a bare copper tube with a copper wire inside of it – a coaxial cable, so to speak.\u00a0 It was so old that the copper was all oxidized and turned dark brown, so I had to polish up the end with some sandpaper.<\/p>\n
Being that it has been chilly, I can turn on the stove burner and put the thermocouple in the flame.\u00a0 I clipped on a cheapo DMM, and measured the voltage with the thermocouple’s tip a dull red, and I got about 42 millivolts.\u00a0 But how much current can this deliver?<\/p>\n
I got a 10 ohm resistor and put it across the wires.\u00a0 The DMM still read 42 millivolts.\u00a0 It didn’t drop at all, so I went and got a 1 ohm resistor and put it across the wires.\u00a0 The meter dropped only 2 millivolts from 42 to 40 mV.\u00a0 That small drop indicates the thermocouple can deliver quite a bit of current.\u00a0 But at 40 millivolts, the impedance is very low, a small fraction of an ohm.<\/p>\n
The big problem is that in order to get enough voltage to run a DC to DC converter, I need to connect at least 20 to 25 thermocouples in series, which will give 0.8 to 1 volt.\u00a0 And there doesn’t seem to be enough room in the flame to put that many thermocouples together, not to mention that they would cost a few hundred dollars.\u00a0 Here is one experimenter’s method<\/a> of generating electricity with thermocouples.<\/p>\n Another way to harvest energy is to use a Peltier junction.\u00a0 They also produce a low voltage, but not as low as a thermocouple.\u00a0 Also, it may be possible to use heat to generate IR (infrared) radiation, and that is then harvested by solar photovoltaic cells.<\/p>\n Back to experimenting…<\/p>\n","protected":false},"excerpt":{"rendered":" I had a thermocouple from an appliance lying around in the garage and I decided that it would be a good idea to experiment with it.\u00a0 It was a used one, but I don’t know what it was from; maybe a water heater.\u00a0 But a long time ago I had cut off the end that <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-5667","post","type-post","status-publish","format-standard","hentry","category-electronics"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5667","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5667"}],"version-history":[{"count":4,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5667\/revisions"}],"predecessor-version":[{"id":5925,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5667\/revisions\/5925"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5667"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5667"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5667"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}