Design Article
Energy harvesting, wireless sensor networks & opportunities for industrial applications
Sebastien Boisseau and Ghislain Despesse, CEA-Leti
2/27/2012 8:45 AM EST
Power, Energy, Measurement cycle frequency – Is an EH-based source viable?
Sensor node’s average power consumption (P) corresponds to the total amount of energy needed for one measurement cycle (W) multiplied by the frequency of this action (f).
Sensor node’s average power consumption (P) corresponds to the total amount of energy needed for one measurement cycle (W) multiplied by the frequency of this action (f).
This simple link between P, W and f can be illustrated by figure 5. By using log-log scales, with energy in abscissa and measurement frequency in ordinate, average power consumption is represented by straight lines of slope -1. Obviously, power sources can also be represented in this diagram. It allows to compare limited sources (batteries, lithium, wood…) and ambient energy sources (e.g. 100µW green line). For example, harvesting 100µW during 1 year corresponds to a total amount of energy equivalent to 1g of lithium.
Moreover, by taking this approach of looking at energy consumption for one measure instead of an average power consumption, it appears that:
1- Sending 100bits of data consumes 5µJ
2- Measuring acceleration consumes 50µJ
3- Making a complete measure: measure+conversion+emission consumes 250-500µJ.
Therefore, with 100µW harvested continuously, it is possible to perform a complete measure every 1-10 seconds (0.1-1Hz). This is in agreement with many industrial needs and especially with predictive maintenance topics.
Figure 5: Power, Energy and Frequency – PWf diagrams
EH Technological offers and actors
According to a study market performed by CEA-Leti, EH-powered aWSN is a field of growing interest. The technological offer is being improved and diversified. For the same reasons, the number of industrial actors increases. Figure 6 presents several industrial actors working on energy harvesting (except photovoltaics). Obviously, many research centers also work on EH (University Of Southampton (UK), MIT (USA), Peking University (CN), Holst Centre (D), Berkeley (US), INSA (FR), LETI (FR), Fraunhofer(D)…)
Figure 6: Industrial actors on EH (except photovoltaics)
Moreover, by taking this approach of looking at energy consumption for one measure instead of an average power consumption, it appears that:
1- Sending 100bits of data consumes 5µJ
2- Measuring acceleration consumes 50µJ
3- Making a complete measure: measure+conversion+emission consumes 250-500µJ.
Therefore, with 100µW harvested continuously, it is possible to perform a complete measure every 1-10 seconds (0.1-1Hz). This is in agreement with many industrial needs and especially with predictive maintenance topics.
Figure 5: Power, Energy and Frequency – PWf diagrams
EH Technological offers and actors
According to a study market performed by CEA-Leti, EH-powered aWSN is a field of growing interest. The technological offer is being improved and diversified. For the same reasons, the number of industrial actors increases. Figure 6 presents several industrial actors working on energy harvesting (except photovoltaics). Obviously, many research centers also work on EH (University Of Southampton (UK), MIT (USA), Peking University (CN), Holst Centre (D), Berkeley (US), INSA (FR), LETI (FR), Fraunhofer(D)…)
Figure 6: Industrial actors on EH (except photovoltaics)
Unfortunately, except for PV cells, EH is still perceived by industrialists as a non-mature technology that requires much improvements before being really interesting and widely used. Nevertheless, its advantages compared to wires or batteries are already well perceived. Table 1 presents some industrialists’ visions of EH (CEA-Leti study market). We compare these results with standard solutions, i.e. batteries and wires.
Table 1: Industrialists’ visions of EH
Table 1: Industrialists’ visions of EH
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Horaira
2/28/2012 2:25 AM EST
Good Article... specially gathered all pieces together.
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wlad01
3/1/2012 1:10 PM EST
Great article indeed; of course Micropelt offers thermoelectric chip-generators (Fig. 6). 100 uW can already be achieved with a temperature difference of just a couple of degrees. Industrial environments offer larger delta-T's, which can create "milliWatts". Thereby also industrial sensors using radio protocols like WHART or ISA100 can be supported by thermal energy harvesting. - Micropelt Germany -
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docdivakar
3/14/2012 10:36 AM EDT
Great summary! Figure 2 says a lot on where to focus for a given application and environment to use the appropriate harvesting technology.
MP Divakar
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jeanlucl1
4/12/2012 8:26 PM EDT
Ghislain, Sebastien,
Tres bon article.
Bien cordialement,
Jean Luc
Jean Luc Lembert
10890 Viacha Drive
San Diego, CA 92124
Phone: (858) 212-4950
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anne-francoise.pele
7/16/2012 11:25 AM EDT
FYI, Stephane Boisseau and Ghislain Despesse at the CEA-Leti (France) also contributed the article, entitled: "Vibration energy harvesting for wireless sensor networks: Assessments and perspectives".
The link to the article is: http://www.eetimes.com/design/smart-energy-design/4370888/Vibration-energy-harvesting-for-wireless-sensor-networks--Assessments-and-perspectives?pageNumber=2&Ecosystem=smart-energy-design#
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anne-francoise.pele
7/20/2012 5:18 PM EDT
Click on the link below to check out the collection of the Design Articles, Case Studies, Product How-To articles, Teardowns, etc... related to energy scavenging that have been published on Smart Energy Designline.
Click here: http://www.eetimes.com/design/smart-energy-design/4372778/Energy-harvesting---Design-archive
Check back frequently. The list will be updated as new articles arrive.
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Smile Stone
11/7/2012 12:46 AM EST
It's Awsome!!!
I want more information about it.
because my company has many vibration equipment.
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