ebm-papst has devel\u00adoped a line of active compact cooling systems specif\u00adi\u00adcally for the market-oriented designs of the new high-perfor\u00admance LEDs.<\/p><\/blockquote>\n
Also, completely new design possi\u00adbil\u00adi\u00adties can be real\u00adized, mini\u00admizing main\u00adte\u00adnance of even very complex lighting systems, such as in museums, theaters, and places of worship, storage facil\u00adi\u00adties, street lighting or stadiums (Fig. 1). Active cooling opens new hori\u00adzons in effi\u00adcient LED lighting.<\/p>\n
Selecting the right light source<\/h2>\n
The correct amount of light deter\u00admines how we perceive the world. This is why there are lighting spec\u00adi\u00adfiers, who can make us see things \u201cin the right light\u201d. However, it is often diffi\u00adcult even for experts to select the right light source. Ideally, a light source should have a universal appli\u00adca\u00adtion, requiring little space or power. CoB lights (Chip on Board) meet a whole range of industry require\u00adments. However, its semi\u00adcon\u00adductor chip must have targeted cooling in order to main\u00adtain its life\u00adtime and color fidelity. To meet the CoB require\u00adments, ebm-papst has devel\u00adoped a line of active compact cooling systems specif\u00adi\u00adcally for the market-oriented designs of the new high-perfor\u00admance LEDs. It saves space and allows completely new lighting possi\u00adbil\u00adi\u00adties.<\/p>\n
LED bulbs \u2013 compact and effi\u00adcient?<\/h2>\n![](\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2017\/10\/LED-lifetime-prediction-450x335.jpg\")
Figure 2: The life expectancy of the LED is essen\u00adtially depen\u00addent on the temper\u00ada\u00adture, which is why targeted heat removal is espe\u00adcially impor\u00adtant.<\/p><\/div><\/div>\n
When you look at the CoB in detail, you will quickly notice several prob\u00adlems (Fig. 2). As a semi\u00adcon\u00adductor, the LED chip can only operate up to a prede\u00adter\u00admined junc\u00adtion temper\u00ada\u00adture. Should the temper\u00ada\u00adture rise, the LED quickly develops chal\u00adlenges. These include a reduc\u00adtion in CRI (color rendering index), effi\u00adcacy and most impor\u00adtantly, a reduc\u00adtion in life\u00adtime.<\/p>\n
But even at lower temper\u00ada\u00adtures, the mate\u00adrial ages rapidly, lumi\u00adnance and effi\u00adciency decrease, the color range reduces- in short, its useful life is down. Despite their high effi\u00adciency, the waste heat of LED surfaces and the high power density of the LED light sources can be formi\u00addable. This amount of waste heat must be dissi\u00adpated in a targeted manner, either by means of conven\u00adtional (often over\u00adsized) passive cooling or via targeted active heat dissi\u00adpa\u00adtion (see text on the box).<\/p>\n
![](\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2017\/10\/cooling-LED-compact-build-450x417.jpg\")
Figure 3: Active cooling solu\u00adtions also impress with their compact design.<\/p><\/div><\/div>\n
In prin\u00adciple, the following must be consid\u00adered: Energy (heat) always flows from hot to cold. For cooling solu\u00adtions, the total heat resis\u00adtance, i.e. the sum of indi\u00advidual paths of thermal resis\u00adtance, must be taken into account. Here, a signif\u00adi\u00adcant differ\u00adence between passive and active cooling concept already emerges: The \u201ccooling pathway\u201d LED Chip \u2013 substrate \u2013 heat sink \u2013 air is always the same, but the mate\u00adrial part of the same cooling perfor\u00admance varies greatly. The more mate\u00adrial is used, the larger the heat sink-is required.<\/p>\n
Smaller LEDs with the same output and passive cooling are not yet capable of producing smaller fixture designs; because they require large heat sinks as the thermal dissipation\/heat transfer to the air becomes a limiting factor for the heat transfer. Passively cooled LEDs there\u00adfore require a high use of mate\u00adrial and are usually neither compact nor envi\u00adron\u00admen\u00adtally friendly. At this point, active cooling concepts offer several distin\u00adguishing advan\u00adtages (Fig. 3).<\/p>\n
Future-proof active cooling<\/h2>\n![](\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2017\/10\/active-cooling-LED-compact-450x254.jpg\")
Figure 4: Heat sinks and fans can be combined into a compact module for common LED cooling solu\u00adtions, which facil\u00adi\u00adtates assembly.<\/p><\/div><\/div>\n
Since the heat dissi\u00adpa\u00adtion from the heat sink to the air is the main resis\u00adtance in the energy discharge, the largest cooling reserves can also be released. A key feature of active cooling is the targeted air supply to the heat sink. Forced convec\u00adtion, or more specif\u00adi\u00adcally turbu\u00adlent flow is gener\u00adated towards the heat sink, which consid\u00ader\u00adably improves heat transfer from the thermal mass of the heat sink itself into the neigh\u00adboring reser\u00advoir of air which surrounds the light fixture.<\/p>\n
Normally, the system works as follows: A small heavy-duty LED surface is attached to the heat sink with a thermal inter\u00adface mate\u00adrial. This provides a much lower thermal resis\u00adtance enabling a greater transfer of heat from the LED into the heat sink, with between four- and six-fold decrease, the fan creating cold fresh air flow. The elec\u00adtronic cooling experts from ebm-papst St. Georgen have now combined heat sinks and fans into a compact module for common LED cooling solu\u00adtion designs, which makes instal\u00adla\u00adtion easier (Fig. 4). Its smaller design also saves not only in mate\u00adrial but also in weight, and the targeted airflow also ensures that heat transfer impairing deposits such as dust do not adhere at all.<\/p>\n
Noise-free, reli\u00adable, long-lasting<\/h2>\n
The ever-changing require\u00adments of modern lighting LED tech\u00adnology demand opti\u00admizing new concepts in simu\u00adla\u00adtion programs with mate\u00adrial-specific, aero\u00addy\u00adnamic and drive-specific details, where effi\u00adcient, reli\u00adable cooling modules can be built in the smallest avail\u00adable space. A six-fold decrease in dimen\u00adsions compared to passive cooling speaks for itself. Other impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p>\n
Most people can perceive noise starting from about 12 dB (A), the fans above reach values between 7 and 19 dB (A), whereas compa\u00adrable fans avail\u00adable on the market start from 18 dB (A) upwards. For compar\u00adison, the noise level in an office is about 35 dB (A), so the modules are inaudible even in museums or theaters. Power consump\u00adtion of the fan is between 0.18 and 1.1 W at 12 VDC. This allows the modules to dissi\u00adpate waste heat reli\u00adably at between 38 and 200 Watts.<\/p>\n
Impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p><\/blockquote>\n
Depending on the output cate\u00adgory, round and square axial compact modules have diam\u00ade\u00adters and side lengths which include 40, 50, 60, 80 or 92 or 119 mm with an overall height of 10 to 25 mm. In the radial version with air deflec\u00adtion at 90 \u00b0, the dimen\u00adsions are 51, 76 or 97 mm with the height of 15 to 33 mm. Thus, compared to passive cooling solu\u00adtions compa\u00adrable to the cooling capacity, 50 to 100 % higher lumi\u00adnance is possible with the same size. Another posi\u00adtive benefit of the targeted active cooling is the low-temper\u00ada\u00adture color fidelity of the LED arrays. Espe\u00adcially in museums, a high CRI is essen\u00adtial to see the illu\u00admi\u00adnated objects in the right light.<\/p>\n
As the cooling modules were devel\u00adoped for world\u00adwide main\u00adte\u00adnance-free use, their service life is compa\u00adrable to the CoB light sources. At 40 \u00b0C, the value is 87,500 to 97,500 h, i.e. around 10 years; at an ambient temper\u00ada\u00adture of 20 \u00b0C, the service life is doubled and can often far exceeds that of the LED itself. The tech\u00adnology from ebm-papst also takes into account an envi\u00adron\u00admen\u00adtally compat\u00adible overall service life concept for devel\u00adop\u00adment, produc\u00adtion, oper\u00ada\u00adtion and disposal.<\/p>\n
As a result of their reduced size, modern compact modules for active LED cooling enable completely new lighting concepts, dras\u00adti\u00adcally shorten the time-to-market for the chip-specific designs and improve the envi\u00adron\u00admental balance of the lighting concepts due to its low main\u00adte\u00adnance.<\/p>\n
\nActive cooling prin\u00adci\u00adples<\/strong><\/h2>\nThe heat discharge coef\u00adfi\u00adcient, which is impor\u00adtant for heat dissi\u00adpa\u00adtion, describes the ability of the air to dissi\u00adpate energy from the surface of a cooler. Among other things, it depends on the air density and the thermal conduc\u00adtivity coef\u00adfi\u00adcients of the heat dissi\u00adpating mate\u00adrial as well as the air. The thermal conduc\u00adtivity coef\u00adfi\u00adcient is usually calcu\u00adlated using the temper\u00ada\u00adture differ\u00adence of the parts involved. In contrast to thermal conduc\u00adtivity, the heat transfer coef\u00adfi\u00adcient is not a mate\u00adrial constant, but is strongly depen\u00addent on the flow velocity or the type of flow (laminar or turbu\u00adlent) as well as the geometric condi\u00adtions and the surface texture. Active cooling employs more effi\u00adcient heat dissi\u00adpa\u00adtion.<\/p>\n
In the case of laminar flow, the air moves in approx\u00adi\u00admately parallel layers. The heat is trans\u00adferred between the layers only by very slow heat conduc\u00adtion. Conversely, in case of turbu\u00adlent flow, inten\u00adsive swirling and shifting occurs. This results in an almost perfect mixing of air flows. Heat transfer in turbu\u00adlent flow is there\u00adfore a lot more effi\u00adcient as in the case of laminar flow, which is used in passive cooling (Fig. 5). To use an example from everyday life, a small hair dryer uses 1.0-1.5 kWatts per a blast of turbu\u00adlent air. On the other hand, an elec\u00adtric convec\u00adtion heater with 1.5 kWatts builds up a lot more with a largely laminar inflow with the same output.<\/p>\n
![](\"https:\/\/ebmpapst-7237.kxcdn.com\/en\/files\/2017\/10\/LED-cooling-surroundings-660x373.jpg\")
Figure 5: The picture shows how the LED heats the heat sink (red, 55 \u00b0C) and the fan blows the cool ambient air (blue, 25 \u00b0C) through the heat sink and thereby limits the maximum temper\u00ada\u00adture at the LED to approx. 60 \u00b0C.<\/p><\/div><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
In most cases, spot lights and flash lights with long-life LED modules in various output cate\u00adgories score highly. Their high lumi\u00adnance enables a targeted light control with overall low power consump\u00adtion. As with all semi\u00adcon\u00adduc\u00adtors, however, the waste heat has to be removed effi\u00adciently, other\u00adwise, it leads to hazardous high temper\u00ada\u00adtures despite high effi\u00adciency of [\u2026]<\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[5,16],"tags":[164],"class_list":["post-12299","post","type-post","status-publish","format-standard","hentry","category-electronics","category-fans","tag-compactpower"],"acf":[],"_links":{"self":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/comments?post=12299"}],"version-history":[{"count":2,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions"}],"predecessor-version":[{"id":22281,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions\/22281"}],"wp:attachment":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/media?parent=12299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/categories?post=12299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/tags?post=12299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Figure 2: The life expectancy of the LED is essen\u00adtially depen\u00addent on the temper\u00ada\u00adture, which is why targeted heat removal is espe\u00adcially impor\u00adtant.<\/p><\/div><\/div>\n
When you look at the CoB in detail, you will quickly notice several prob\u00adlems (Fig. 2). As a semi\u00adcon\u00adductor, the LED chip can only operate up to a prede\u00adter\u00admined junc\u00adtion temper\u00ada\u00adture. Should the temper\u00ada\u00adture rise, the LED quickly develops chal\u00adlenges. These include a reduc\u00adtion in CRI (color rendering index), effi\u00adcacy and most impor\u00adtantly, a reduc\u00adtion in life\u00adtime.<\/p>\n
But even at lower temper\u00ada\u00adtures, the mate\u00adrial ages rapidly, lumi\u00adnance and effi\u00adciency decrease, the color range reduces- in short, its useful life is down. Despite their high effi\u00adciency, the waste heat of LED surfaces and the high power density of the LED light sources can be formi\u00addable. This amount of waste heat must be dissi\u00adpated in a targeted manner, either by means of conven\u00adtional (often over\u00adsized) passive cooling or via targeted active heat dissi\u00adpa\u00adtion (see text on the box).<\/p>\n
Figure 3: Active cooling solu\u00adtions also impress with their compact design.<\/p><\/div><\/div>\n
In prin\u00adciple, the following must be consid\u00adered: Energy (heat) always flows from hot to cold. For cooling solu\u00adtions, the total heat resis\u00adtance, i.e. the sum of indi\u00advidual paths of thermal resis\u00adtance, must be taken into account. Here, a signif\u00adi\u00adcant differ\u00adence between passive and active cooling concept already emerges: The \u201ccooling pathway\u201d LED Chip \u2013 substrate \u2013 heat sink \u2013 air is always the same, but the mate\u00adrial part of the same cooling perfor\u00admance varies greatly. The more mate\u00adrial is used, the larger the heat sink-is required.<\/p>\n
Smaller LEDs with the same output and passive cooling are not yet capable of producing smaller fixture designs; because they require large heat sinks as the thermal dissipation\/heat transfer to the air becomes a limiting factor for the heat transfer. Passively cooled LEDs there\u00adfore require a high use of mate\u00adrial and are usually neither compact nor envi\u00adron\u00admen\u00adtally friendly. At this point, active cooling concepts offer several distin\u00adguishing advan\u00adtages (Fig. 3).<\/p>\n
Future-proof active cooling<\/h2>\nFigure 4: Heat sinks and fans can be combined into a compact module for common LED cooling solu\u00adtions, which facil\u00adi\u00adtates assembly.<\/p><\/div><\/div>\n
Since the heat dissi\u00adpa\u00adtion from the heat sink to the air is the main resis\u00adtance in the energy discharge, the largest cooling reserves can also be released. A key feature of active cooling is the targeted air supply to the heat sink. Forced convec\u00adtion, or more specif\u00adi\u00adcally turbu\u00adlent flow is gener\u00adated towards the heat sink, which consid\u00ader\u00adably improves heat transfer from the thermal mass of the heat sink itself into the neigh\u00adboring reser\u00advoir of air which surrounds the light fixture.<\/p>\n
Normally, the system works as follows: A small heavy-duty LED surface is attached to the heat sink with a thermal inter\u00adface mate\u00adrial. This provides a much lower thermal resis\u00adtance enabling a greater transfer of heat from the LED into the heat sink, with between four- and six-fold decrease, the fan creating cold fresh air flow. The elec\u00adtronic cooling experts from ebm-papst St. Georgen have now combined heat sinks and fans into a compact module for common LED cooling solu\u00adtion designs, which makes instal\u00adla\u00adtion easier (Fig. 4). Its smaller design also saves not only in mate\u00adrial but also in weight, and the targeted airflow also ensures that heat transfer impairing deposits such as dust do not adhere at all.<\/p>\n
Noise-free, reli\u00adable, long-lasting<\/h2>\n
The ever-changing require\u00adments of modern lighting LED tech\u00adnology demand opti\u00admizing new concepts in simu\u00adla\u00adtion programs with mate\u00adrial-specific, aero\u00addy\u00adnamic and drive-specific details, where effi\u00adcient, reli\u00adable cooling modules can be built in the smallest avail\u00adable space. A six-fold decrease in dimen\u00adsions compared to passive cooling speaks for itself. Other impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p>\n
Most people can perceive noise starting from about 12 dB (A), the fans above reach values between 7 and 19 dB (A), whereas compa\u00adrable fans avail\u00adable on the market start from 18 dB (A) upwards. For compar\u00adison, the noise level in an office is about 35 dB (A), so the modules are inaudible even in museums or theaters. Power consump\u00adtion of the fan is between 0.18 and 1.1 W at 12 VDC. This allows the modules to dissi\u00adpate waste heat reli\u00adably at between 38 and 200 Watts.<\/p>\n
Impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p><\/blockquote>\n
Depending on the output cate\u00adgory, round and square axial compact modules have diam\u00ade\u00adters and side lengths which include 40, 50, 60, 80 or 92 or 119 mm with an overall height of 10 to 25 mm. In the radial version with air deflec\u00adtion at 90 \u00b0, the dimen\u00adsions are 51, 76 or 97 mm with the height of 15 to 33 mm. Thus, compared to passive cooling solu\u00adtions compa\u00adrable to the cooling capacity, 50 to 100 % higher lumi\u00adnance is possible with the same size. Another posi\u00adtive benefit of the targeted active cooling is the low-temper\u00ada\u00adture color fidelity of the LED arrays. Espe\u00adcially in museums, a high CRI is essen\u00adtial to see the illu\u00admi\u00adnated objects in the right light.<\/p>\n
As the cooling modules were devel\u00adoped for world\u00adwide main\u00adte\u00adnance-free use, their service life is compa\u00adrable to the CoB light sources. At 40 \u00b0C, the value is 87,500 to 97,500 h, i.e. around 10 years; at an ambient temper\u00ada\u00adture of 20 \u00b0C, the service life is doubled and can often far exceeds that of the LED itself. The tech\u00adnology from ebm-papst also takes into account an envi\u00adron\u00admen\u00adtally compat\u00adible overall service life concept for devel\u00adop\u00adment, produc\u00adtion, oper\u00ada\u00adtion and disposal.<\/p>\n
As a result of their reduced size, modern compact modules for active LED cooling enable completely new lighting concepts, dras\u00adti\u00adcally shorten the time-to-market for the chip-specific designs and improve the envi\u00adron\u00admental balance of the lighting concepts due to its low main\u00adte\u00adnance.<\/p>\n
\nActive cooling prin\u00adci\u00adples<\/strong><\/h2>\nThe heat discharge coef\u00adfi\u00adcient, which is impor\u00adtant for heat dissi\u00adpa\u00adtion, describes the ability of the air to dissi\u00adpate energy from the surface of a cooler. Among other things, it depends on the air density and the thermal conduc\u00adtivity coef\u00adfi\u00adcients of the heat dissi\u00adpating mate\u00adrial as well as the air. The thermal conduc\u00adtivity coef\u00adfi\u00adcient is usually calcu\u00adlated using the temper\u00ada\u00adture differ\u00adence of the parts involved. In contrast to thermal conduc\u00adtivity, the heat transfer coef\u00adfi\u00adcient is not a mate\u00adrial constant, but is strongly depen\u00addent on the flow velocity or the type of flow (laminar or turbu\u00adlent) as well as the geometric condi\u00adtions and the surface texture. Active cooling employs more effi\u00adcient heat dissi\u00adpa\u00adtion.<\/p>\n
In the case of laminar flow, the air moves in approx\u00adi\u00admately parallel layers. The heat is trans\u00adferred between the layers only by very slow heat conduc\u00adtion. Conversely, in case of turbu\u00adlent flow, inten\u00adsive swirling and shifting occurs. This results in an almost perfect mixing of air flows. Heat transfer in turbu\u00adlent flow is there\u00adfore a lot more effi\u00adcient as in the case of laminar flow, which is used in passive cooling (Fig. 5). To use an example from everyday life, a small hair dryer uses 1.0-1.5 kWatts per a blast of turbu\u00adlent air. On the other hand, an elec\u00adtric convec\u00adtion heater with 1.5 kWatts builds up a lot more with a largely laminar inflow with the same output.<\/p>\n
Figure 5: The picture shows how the LED heats the heat sink (red, 55 \u00b0C) and the fan blows the cool ambient air (blue, 25 \u00b0C) through the heat sink and thereby limits the maximum temper\u00ada\u00adture at the LED to approx. 60 \u00b0C.<\/p><\/div><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
In most cases, spot lights and flash lights with long-life LED modules in various output cate\u00adgories score highly. Their high lumi\u00adnance enables a targeted light control with overall low power consump\u00adtion. As with all semi\u00adcon\u00adduc\u00adtors, however, the waste heat has to be removed effi\u00adciently, other\u00adwise, it leads to hazardous high temper\u00ada\u00adtures despite high effi\u00adciency of [\u2026]<\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[5,16],"tags":[164],"class_list":["post-12299","post","type-post","status-publish","format-standard","hentry","category-electronics","category-fans","tag-compactpower"],"acf":[],"_links":{"self":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/comments?post=12299"}],"version-history":[{"count":2,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions"}],"predecessor-version":[{"id":22281,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions\/22281"}],"wp:attachment":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/media?parent=12299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/categories?post=12299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/tags?post=12299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Figure 4: Heat sinks and fans can be combined into a compact module for common LED cooling solu\u00adtions, which facil\u00adi\u00adtates assembly.<\/p><\/div><\/div>\n
Since the heat dissi\u00adpa\u00adtion from the heat sink to the air is the main resis\u00adtance in the energy discharge, the largest cooling reserves can also be released. A key feature of active cooling is the targeted air supply to the heat sink. Forced convec\u00adtion, or more specif\u00adi\u00adcally turbu\u00adlent flow is gener\u00adated towards the heat sink, which consid\u00ader\u00adably improves heat transfer from the thermal mass of the heat sink itself into the neigh\u00adboring reser\u00advoir of air which surrounds the light fixture.<\/p>\n
Normally, the system works as follows: A small heavy-duty LED surface is attached to the heat sink with a thermal inter\u00adface mate\u00adrial. This provides a much lower thermal resis\u00adtance enabling a greater transfer of heat from the LED into the heat sink, with between four- and six-fold decrease, the fan creating cold fresh air flow. The elec\u00adtronic cooling experts from ebm-papst St. Georgen have now combined heat sinks and fans into a compact module for common LED cooling solu\u00adtion designs, which makes instal\u00adla\u00adtion easier (Fig. 4). Its smaller design also saves not only in mate\u00adrial but also in weight, and the targeted airflow also ensures that heat transfer impairing deposits such as dust do not adhere at all.<\/p>\n
Noise-free, reli\u00adable, long-lasting<\/h2>\n
The ever-changing require\u00adments of modern lighting LED tech\u00adnology demand opti\u00admizing new concepts in simu\u00adla\u00adtion programs with mate\u00adrial-specific, aero\u00addy\u00adnamic and drive-specific details, where effi\u00adcient, reli\u00adable cooling modules can be built in the smallest avail\u00adable space. A six-fold decrease in dimen\u00adsions compared to passive cooling speaks for itself. Other impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p>\n
Most people can perceive noise starting from about 12 dB (A), the fans above reach values between 7 and 19 dB (A), whereas compa\u00adrable fans avail\u00adable on the market start from 18 dB (A) upwards. For compar\u00adison, the noise level in an office is about 35 dB (A), so the modules are inaudible even in museums or theaters. Power consump\u00adtion of the fan is between 0.18 and 1.1 W at 12 VDC. This allows the modules to dissi\u00adpate waste heat reli\u00adably at between 38 and 200 Watts.<\/p>\n
Impor\u00adtant require\u00adments for the use of active cooling are low oper\u00adating noise and a longer service life.<\/p><\/blockquote>\n
Depending on the output cate\u00adgory, round and square axial compact modules have diam\u00ade\u00adters and side lengths which include 40, 50, 60, 80 or 92 or 119 mm with an overall height of 10 to 25 mm. In the radial version with air deflec\u00adtion at 90 \u00b0, the dimen\u00adsions are 51, 76 or 97 mm with the height of 15 to 33 mm. Thus, compared to passive cooling solu\u00adtions compa\u00adrable to the cooling capacity, 50 to 100 % higher lumi\u00adnance is possible with the same size. Another posi\u00adtive benefit of the targeted active cooling is the low-temper\u00ada\u00adture color fidelity of the LED arrays. Espe\u00adcially in museums, a high CRI is essen\u00adtial to see the illu\u00admi\u00adnated objects in the right light.<\/p>\n
As the cooling modules were devel\u00adoped for world\u00adwide main\u00adte\u00adnance-free use, their service life is compa\u00adrable to the CoB light sources. At 40 \u00b0C, the value is 87,500 to 97,500 h, i.e. around 10 years; at an ambient temper\u00ada\u00adture of 20 \u00b0C, the service life is doubled and can often far exceeds that of the LED itself. The tech\u00adnology from ebm-papst also takes into account an envi\u00adron\u00admen\u00adtally compat\u00adible overall service life concept for devel\u00adop\u00adment, produc\u00adtion, oper\u00ada\u00adtion and disposal.<\/p>\n
As a result of their reduced size, modern compact modules for active LED cooling enable completely new lighting concepts, dras\u00adti\u00adcally shorten the time-to-market for the chip-specific designs and improve the envi\u00adron\u00admental balance of the lighting concepts due to its low main\u00adte\u00adnance.<\/p>\n
\nActive cooling prin\u00adci\u00adples<\/strong><\/h2>\n
The heat discharge coef\u00adfi\u00adcient, which is impor\u00adtant for heat dissi\u00adpa\u00adtion, describes the ability of the air to dissi\u00adpate energy from the surface of a cooler. Among other things, it depends on the air density and the thermal conduc\u00adtivity coef\u00adfi\u00adcients of the heat dissi\u00adpating mate\u00adrial as well as the air. The thermal conduc\u00adtivity coef\u00adfi\u00adcient is usually calcu\u00adlated using the temper\u00ada\u00adture differ\u00adence of the parts involved. In contrast to thermal conduc\u00adtivity, the heat transfer coef\u00adfi\u00adcient is not a mate\u00adrial constant, but is strongly depen\u00addent on the flow velocity or the type of flow (laminar or turbu\u00adlent) as well as the geometric condi\u00adtions and the surface texture. Active cooling employs more effi\u00adcient heat dissi\u00adpa\u00adtion.<\/p>\n
In the case of laminar flow, the air moves in approx\u00adi\u00admately parallel layers. The heat is trans\u00adferred between the layers only by very slow heat conduc\u00adtion. Conversely, in case of turbu\u00adlent flow, inten\u00adsive swirling and shifting occurs. This results in an almost perfect mixing of air flows. Heat transfer in turbu\u00adlent flow is there\u00adfore a lot more effi\u00adcient as in the case of laminar flow, which is used in passive cooling (Fig. 5). To use an example from everyday life, a small hair dryer uses 1.0-1.5 kWatts per a blast of turbu\u00adlent air. On the other hand, an elec\u00adtric convec\u00adtion heater with 1.5 kWatts builds up a lot more with a largely laminar inflow with the same output.<\/p>\n
Figure 5: The picture shows how the LED heats the heat sink (red, 55 \u00b0C) and the fan blows the cool ambient air (blue, 25 \u00b0C) through the heat sink and thereby limits the maximum temper\u00ada\u00adture at the LED to approx. 60 \u00b0C.<\/p><\/div><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
In most cases, spot lights and flash lights with long-life LED modules in various output cate\u00adgories score highly. Their high lumi\u00adnance enables a targeted light control with overall low power consump\u00adtion. As with all semi\u00adcon\u00adduc\u00adtors, however, the waste heat has to be removed effi\u00adciently, other\u00adwise, it leads to hazardous high temper\u00ada\u00adtures despite high effi\u00adciency of [\u2026]<\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"wp_typography_post_enhancements_disabled":false,"footnotes":""},"categories":[5,16],"tags":[164],"class_list":["post-12299","post","type-post","status-publish","format-standard","hentry","category-electronics","category-fans","tag-compactpower"],"acf":[],"_links":{"self":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/comments?post=12299"}],"version-history":[{"count":2,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions"}],"predecessor-version":[{"id":22281,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/posts\/12299\/revisions\/22281"}],"wp:attachment":[{"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/media?parent=12299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/categories?post=12299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mag.ebmpapst.com\/en\/wp-json\/wp\/v2\/tags?post=12299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}