{"id":5028,"date":"2023-08-30T12:51:49","date_gmt":"2023-08-30T12:51:49","guid":{"rendered":"https:\/\/csiag.eu\/?p=5028"},"modified":"2024-05-18T14:43:42","modified_gmt":"2024-05-18T14:43:42","slug":"refrigerator-fan-control","status":"publish","type":"post","link":"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/","title":{"rendered":"Refrigerator \u2013 Fan Control"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Funktionsweise_Absorber\" >How absorbers work<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Kuhlung_fur_den_Kondensator\" >Cooling for the condenser<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Lufter-Regelung\" >Fan control<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Programmierung\" >programming<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Legende\" >Legend:<\/a><\/li><\/ul><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/#Temperatursensor_im_Gefrierfach\" >Temperature sensor in the freezer compartment<\/a><\/li><\/ul><\/nav><\/div>\n<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading time<\/span> <span class=\"rt-time\"> 5<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span>\n<p>Especially with absorption refrigerators, it is a problem to get the required cooling performance from the refrigerator in warm seasons, especially in southern and therefore warmer climes. A fan control can help.<\/p>\n\n\n\n<p>The difference with and without the fan is clear: without the fan, the temperature in the freezer compartment is between 7 ... 11 \u00b0C, with fan after a short time -20 \u00b0C! <\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Funktionsweise_Absorber\"><\/span>How absorbers work<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>An absorber, unlike a compressor, works with water and ammonia in a hydrogen atmosphere. Hydrogen acts as a pressure equalizer. Water and ammonia are heated in the so-called \u201ccooker\u201d, mainly using gas, 230 V AC or 12 V DC, but also petrol.<\/p>\n\n\n\n<p>The ammonia becomes gaseous as a result of heating. It cools down via the condenser (located behind the upper vent in the caravan or motorhome wall) and, in turn, reaches the evaporator (located in the freezer compartment of the refrigerator) in a liquefied form, in which the hydrogen compensates for the pressure differences that arise when the ammonia evaporates again and produces the desired one Cold is generated. In the absorber, the ammonia dissolves again with the water and the cycle begins again.<\/p>\n\n\n\n<p>A low cooling performance at higher outside temperatures is due to the fact that not enough ammonia in liquefied form can be fed into the evaporator because it cannot cool down sufficiently on the way through the condenser.<\/p>\n\n\n\n<p>If the condenser is additionally cooled by fans with an increased air flow, more ammonia liquefies and the cooling performance increases accordingly.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Kuhlung_fur_den_Kondensator\"><\/span>Cooling for the condenser<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Some absorption refrigerators already have one or two additional fans with temperature control. If this is not enough, you can remedy the situation yourself. SmartHome makes it possible.<\/p>\n\n\n\n<p>First you need suitable fans, <a href=\"https:\/\/www.amazon.de\/dp\/B09722FQHV?ref=ppx_yo2ov_dt_b_product_details&amp;th=1\" target=\"_blank\" rel=\"noopener\">this<\/a> are available in packs of three (360 x 120 x 25 mm). Together they have an air flow of 7 m<sup>3<\/sup>\/H. They are designed for 12 V DC, but are supplied with a 230 V power supply. Of course a 12 V control would have been nicer. In order to be able to control the fans individually, the cable must be cut directly before the three individual lines are combined.<\/p>\n\n\n\n<p>Installation is carried out using a 30 x 30 mm aluminum angle strip, which is held horizontally using a double-sided <a href=\"https:\/\/www.amazon.de\/dp\/B086RQZYTM?psc=1&amp;ref=ppx_yo2ov_dt_b_product_details\" target=\"_blank\" rel=\"noopener\">duct tape<\/a> glued to the inside of the wall. The fans are also attached in the same way. The thick adhesive tape largely decouples running noises, although unfortunately not completely.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"800\" height=\"308\" src=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/Ventilatoren_KS-2.jpg\" alt=\"\" class=\"wp-image-5037\" srcset=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/Ventilatoren_KS-2.jpg 800w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/Ventilatoren_KS-2-300x116.jpg 300w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/Ventilatoren_KS-2-768x296.jpg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Lufter-Regelung\"><\/span>Fan control<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Well, if the performance cannot be regulated via the speed, then by activating one, two or all three fans depending on the temperature difference in front of the condenser and after the evaporator.<\/p>\n\n\n\n<p>A <a href=\"https:\/\/de.elv.com\/homematic-differenz-temperatur-sensor-hm-wds30-ot2-sm-2-fuer-smart-home-hausautomation-143420\" target=\"_blank\" rel=\"noopener\">Homematic temperature difference sensor<\/a> (Sensor 1 is attached to the top of the condenser using a cable tie, sensor 2 is attached to the lower pipe after the evaporator), determines the necessary values and is also attached to a free area behind the lower ventilation opening in the caravan or motorhome wall using double-sided adhesive tape.<br>Anyone who doesn&#039;t like batteries or accumulators (2x AA) but wants to use the 12 V DC on-board network will find this <a href=\"https:\/\/csiag.eu\/en\/temperature-measurement\/\" data-type=\"link\" data-id=\"https:\/\/csiag.eu\/temperatur-messung\/\">here<\/a> instructions on how a DCDC converter 12 V \/ 3.3 V can be integrated into the temperature difference sensor for this purpose.<\/p>\n\n\n\n<p>A Homematic 4-way switching actuator supplies the three individual fans with 12V via channels 1, 2 and 3.<br><strong>Danger<\/strong> \u2013 There are different versions of the 4-way switching actuator: at the <a href=\"https:\/\/de.elv.com\/homematic-funk-schaltaktor-4-fach-hm-lc-sw4-wm-fuer-smart-home-hausautomation-099082?fs=240820572\" target=\"_blank\" rel=\"noopener\">Version with mechanical relays<\/a> you are free to choose the switching polarity (plus or minus), while the purely electronic ones, which switch via switching transistors, usually switch minus, i.e. here all plus lines must be connected directly to plus, while the minus lines are connected to the screw terminals of channels 1 .. 3 can be connected.<br>This can also be mounted in the same way.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Programmierung\"><\/span>programming<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>For the sake of simplicity, a separate program is created for each fan, which switches on the respective fan depending on the temperature difference threshold. also for the switch-off process when the switching threshold is undershot.<\/p>\n\n\n\n<p class=\"text-indent: 10px;\">Here is an example for the fan on channel 1:<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" style=\"padding-left: 40px;\"><span class=\"ez-toc-section\" id=\"Legende\"><\/span>Legend:<span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<p><p class=\"text-indent: 10px;\" style=\"padding-left: 80px;\">KS_TDS_Diff_K3 -&gt; Name* of channel 3 of the temperature difference sensor <br>KS_Lft -&gt; created <a href=\"https:\/\/csiag.eu\/en\/smarthome-system-variables\/\">variable<\/a>** (true or not true)<br>KS_SW_Lft1_K1 -&gt; Name* of channel 1 of the switching actuator<br>KS_SW_Lft2_K2 -&gt; Name* of channel 2 of the switching actuator<br>KS_SW_Lft3_K3 -&gt; Name* of channel 3 of the switching actuator<br>KS_SW_Lft4_K4 -&gt; Name* of channel 4 of the switching actuator<\/p><\/p>\n\n\n\n<p><p style=\"padding-left: 80px;\">* will after <a href=\"https:\/\/csiag.eu\/en\/teach-smarthome-devices\/\" data-type=\"post\" data-id=\"73\">Training<\/a> of the device manually<br>** A variable to be checked is used to decide whether a subsequent action <br>&nbsp; &nbsp; is initiated or not.<br>&nbsp; &nbsp; (Here, for example, the fan should not be activated at night to create background noise. <br>&nbsp; &nbsp; &nbsp;Consequently, the variable in the night time is set up in a separate program <br>&nbsp; &nbsp; &nbsp;\u201cnot true\u201d, set to \u201ctrue\u201d during the day)<\/p><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Turn on<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"324\" src=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6-1024x324.png\" alt=\"\" class=\"wp-image-5029\" srcset=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6-1024x324.png 1024w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6-1536x485.png 1536w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6-300x95.png 300w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6-768x243.png 768w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-6.png 1924w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Fan 2 is switched on when a differential temperature* of 16 \u00b0C is exceeded, fan 3 from 24 \u00b0C.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Turn off<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"358\" src=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7-1024x358.png\" alt=\"\" class=\"wp-image-5030\" srcset=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7-1024x358.png 1024w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7-1536x538.png 1536w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7-300x105.png 300w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7-768x269.png 768w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-7.png 1926w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Fan 2 is switched off when the differential temperature* falls below 8 \u00b0C, fan 3 when the temperature drops below 16 \u00b0C.<\/p>\n\n\n\n<p>A variable <code>SV_KS_Lft<\/code> can be used to make a decision that allows you to generally allow or prevent the action of the fans, for example if you are sensitive to noise at night and therefore the fans should not run.<\/p>\n\n\n\n<p>*The difference temperature here is arbitrarily set to the values mentioned only as an example. In reality, at outside temperatures of around 5 to 10 \u00b0C, you should determine the temperature difference that occurs - without active ventilation. As the outside temperature rises, you monitor the change in this temperature difference and adjust the point of use of the fans accordingly.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Manual control<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"328\" src=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8-1024x328.png\" alt=\"\" class=\"wp-image-5031\" srcset=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8-1024x328.png 1024w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8-1536x492.png 1536w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8-300x96.png 300w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8-768x246.png 768w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-8.png 1924w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Manual and time-dependent control<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"399\" src=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9-1024x399.png\" alt=\"\" class=\"wp-image-5032\" srcset=\"https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9-1024x399.png 1024w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9-1536x599.png 1536w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9-300x117.png 300w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9-768x299.png 768w, https:\/\/csiag.eu\/wp-content\/uploads\/2023\/08\/image-9.png 1924w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Here the variable is either set manually to \u201cfalse\u201d in order to switch off all fans or automatically, depending on the selected time period, here daily from 10 p.m. to 7 a.m.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Temperatursensor_im_Gefrierfach\"><\/span>Temperature sensor in the freezer compartment<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>If you want to play it safe and make the fan action dependent on the temperature in the freezer compartment, drill a hole of about 5 mm (diameter of the temperature sensor) at the top left of the heat exchanger in the freezer compartment, insert the temperature sensor into this hole from behind, push it forward so that it just appears inside the freezer compartment with its cable strain relief and seal the hole and cable with silicone from behind.<\/p>\n\n\n\n<p>The temperature sensor can be of the type <a href=\"https:\/\/www.eq-3.de\/produkte\/homematic\/detail\/hm-wds30-t-o.html\" target=\"_blank\" rel=\"noreferrer noopener\">HM-WDS30-T-O<\/a> (1-channel) or <a href=\"https:\/\/de.elv.com\/homematic-differenz-temperatur-sensor-hm-wds30-ot2-sm-2-fuer-smart-home-hausautomation-143420\" target=\"_blank\" rel=\"noreferrer noopener\">HM-WDS30-OT2-SM-2<\/a> (2-channel).<\/p>\n\n\n\n<p>In this case, programming is not carried out via the difference channel (<em>K3<\/em>), but the associated sensor channel (for the single-channel sensor <em>K1<\/em>) by switching on a fan when the measured temperature falls below -18 \u00b0C, for example.<\/p>\n\n\n\n<p>The second fan comes into action when the temperature reaches -16 \u00b0C, for example, and the third fan at -14 \u00b0C. In this way, the desired temperature (here e.g. -20 \u00b0C) can be reached again very quickly, especially when the outside temperature is high.<\/p>","protected":false},"excerpt":{"rendered":"<p><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Reading time<\/span> <span class=\"rt-time\"> 5<\/span> <span class=\"rt-label rt-postfix\">minutes<\/span><\/span>With absorption refrigerators in particular, it is a problem to elicit the required cooling capacity from the refrigerator at warm times of the year, especially in warmer, more southerly climes. A fan control can provide a remedy. The difference with and without a fan is clear: without a fan, the temperature in the freezer compartment is between 7 ... 11 \u00b0C, with a fan after a short...&nbsp;<a href=\"https:\/\/csiag.eu\/en\/blog\/2023\/08\/30\/kuehlschrank-ventilator-steuerung\/\" rel=\"bookmark\">Read More \"<span class=\"screen-reader-text\">Refrigerator \u2013 Fan Control<\/span><\/a><\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"off","neve_meta_content_width":70,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[2106,346],"tags":[],"class_list":["post-5028","post","type-post","status-publish","format-standard","hentry","category-absorber-kuehlschrank","category-smarthome"],"modified_by":"Achim Goerner","_links":{"self":[{"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/posts\/5028","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/comments?post=5028"}],"version-history":[{"count":0,"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/posts\/5028\/revisions"}],"wp:attachment":[{"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/media?parent=5028"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/categories?post=5028"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/csiag.eu\/en\/wp-json\/wp\/v2\/tags?post=5028"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}