{"id":2471,"date":"2026-06-19T11:11:43","date_gmt":"2026-06-19T03:11:43","guid":{"rendered":"https:\/\/szfengheng.com\/cdu-cooling-fan-comparison-92mm-120mm-pwm\/"},"modified":"2026-06-19T21:25:10","modified_gmt":"2026-06-19T13:25:10","slug":"cdu-cooling-fan-comparison-92mm-120mm-pwm","status":"publish","type":"post","link":"https:\/\/szfengheng.com\/fr\/cdu-cooling-fan-comparison-92mm-120mm-pwm\/","title":{"rendered":"CDU Pump Station Cooling Fan Comparison: 92mm vs 120mm PWM for Coolant Distribution Units"},"content":{"rendered":"<p><script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"TechArticle\",\n  \"headline\": \"CDU Cooling Fan Comparison: 92mm vs 120mm PWM for Coolant Distribution Units\",\n  \"description\": \"Technical comparison of 92mm and 120mm PWM cooling fans for Coolant Distribution Units in AI liquid cooling systems, including performance, noise, and application guidance.\",\n  \"url\": \"https:\/\/szfengheng.com\/cdu-cooling-fan-comparison-92mm-120mm-pwm\/\",\n  \"datePublished\": \"2026-06-19\",\n  \"dateModified\": \"2026-06-19\",\n  \"author\": {\"@type\": \"Organization\",\"name\": \"Fengheng Technology\",\"url\": \"https:\/\/szfengheng.com\"},\n  \"publisher\": {\"@type\": \"Organization\",\"name\": \"Fengheng Technology\",\"url\": \"https:\/\/szfengheng.com\"},\n  \"keywords\": \"CDU cooling fan 92mm 120mm PWM, coolant distribution unit fan, AI liquid cooling CDU\"\n}\n<\/script><\/p>\n<p><script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What size fan is best for a CDU cooling unit?\",\n      \"acceptedAnswer\": {\"@type\": \"Answer\",\"text\": \"CDU fan size depends on heat rejection capacity. For CDUs handling 15\u201330 kW, 92mm fans (80 CFM each) work well in compact configurations. For 40\u201380 kW CDU stations, 120mm fans (110\u2013140 CFM each) provide higher airflow with lower noise. Fengheng Technology offers 92\u00d725mm, 120\u00d725mm, and 120\u00d738mm models for CDU applications.\"}\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What static pressure do CDU fans need?\",\n      \"acceptedAnswer\": {\"@type\": \"Answer\",\"text\": \"CDU internal heat exchangers typically create 100\u2013200 Pa resistance. CDU fans should deliver \u2265250 Pa minimum, with 350\u2013420 Pa providing comfortable margin for full-speed operation and future capacity increases. Fengheng Technology CDU fans deliver 350 Pa (92mm) to 420 Pa (120\u00d738mm).\"}\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can CDU fans use 48V DC power?\",\n      \"acceptedAnswer\": {\"@type\": \"Answer\",\"text\": \"Yes. OCP Open Rack v3 CDU stations use 48V DC power distribution. Fengheng Technology 48V DC CDU fans eliminate the need for DC-DC converters, improving system efficiency by 3\u20135% and simplifying the power architecture. 48V DC models are available in 92mm, 120mm, and 172mm sizes.\"}\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What is the noise level difference between 92mm and 120mm CDU fans?\",\n      \"acceptedAnswer\": {\"@type\": \"Answer\",\"text\": \"At equivalent airflow, 120mm fans operate at lower RPM than 92mm fans, resulting in 3\u20136 dB lower noise. A 120\u00d725mm fan delivering 110 CFM at 5,500 RPM produces approximately 48 dB(A), while a 92\u00d725mm fan at similar airflow requires 8,000 RPM and produces 54 dB(A). For data centers with strict acoustic requirements, 120mm fans are preferred.\"}\n    }\n  ]\n}\n<\/script><\/p>\n<h2>CDU Fan Selection: The 92mm vs 120mm Decision<\/h2>\n<p>Coolant Distribution Units are the heart of AI liquid cooling infrastructure. They circulate chilled water or dielectric fluid to server cold plates and include internal heat exchangers that must reject heat to room air or building chilled water. The fans inside the CDU cabinet drive airflow across these heat exchangers, and choosing the wrong size fan leads to either inadequate cooling or unnecessary noise and energy consumption.<\/p>\n<h2>How CDU Heat Rejection Works<\/h2>\n<p>A typical CDU for AI GPU clusters handles primary loop coolant returning from server cold plates at 35\u201345\u00b0C. The CDU heat exchanger transfers this heat to:<\/p>\n<ul>\n<li><strong>Building chilled water<\/strong> (if using water-side economizer): Fans may be minimal or not needed<\/li>\n<li><strong>Room air<\/strong> (in adiabatic or air-cooled CDU): Fans are the primary heat rejection mechanism<\/li>\n<\/ul>\n<p>For air-cooled CDU configurations \u2014 common in edge AI deployments and smaller installations \u2014 fan selection directly determines maximum heat rejection capacity and CDU operating temperature limits.<\/p>\n<h2>92mm Fan Characteristics for CDU Applications<\/h2>\n<p><strong>Advantages of 92mm CDU fans:<\/strong><\/p>\n<ul>\n<li>High rotational speed (up to 8,000 RPM) enables aggressive PWM speed range<\/li>\n<li>Compact footprint allows dense fan arrays in limited CDU cabinet space<\/li>\n<li>Lower cost per unit \u2014 beneficial for redundant N+2 configurations<\/li>\n<li>Faster spin-up response for sudden heat load changes<\/li>\n<\/ul>\n<p><strong>Limitations:<\/strong><\/p>\n<ul>\n<li>Higher noise at maximum speed (54\u201358 dB(A) at 8,000 RPM)<\/li>\n<li>Lower maximum airflow per unit (80 CFM) requires more fans for high-capacity CDUs<\/li>\n<li>Higher vibration at maximum speed can affect bearing life in continuous operation<\/li>\n<\/ul>\n<p><strong>Best for:<\/strong> CDU stations handling 15\u201330 kW, compact CDU chassis, edge AI deployments<\/p>\n<h2>120mm Fan Characteristics for CDU Applications<\/h2>\n<p><strong>Advantages of 120mm CDU fans:<\/strong><\/p>\n<ul>\n<li>Higher airflow per unit (110\u2013140 CFM) means fewer fans required for equivalent cooling<\/li>\n<li>Lower operating RPM (4,500\u20135,500 RPM) at equivalent airflow reduces noise by 4\u20136 dB<\/li>\n<li>Lower vibration extends bearing life in 24\/7 continuous operation<\/li>\n<li>Available in 120\u00d725mm (thin) and 120\u00d738mm (thick) variants for different depth constraints<\/li>\n<\/ul>\n<p><strong>Limitations:<\/strong><\/p>\n<ul>\n<li>Larger footprint limits density in compact CDU cabinets<\/li>\n<li>Higher per-unit cost<\/li>\n<\/ul>\n<p><strong>Best for:<\/strong> CDU stations handling 40\u2013100 kW, primary loop CDU installations, data center deployments with strict acoustic limits<\/p>\n<h2>Performance Comparison Table<\/h2>\n<table>\n<thead>\n<tr>\n<th>Specification<\/th>\n<th>92\u00d725mm<\/th>\n<th>120\u00d725mm<\/th>\n<th>120\u00d738mm<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Max RPM<\/td>\n<td>8,000<\/td>\n<td>5,500<\/td>\n<td>4,500<\/td>\n<\/tr>\n<tr>\n<td>Max Airflow<\/td>\n<td>80 CFM<\/td>\n<td>110 CFM<\/td>\n<td>140 CFM<\/td>\n<\/tr>\n<tr>\n<td>Static Pressure<\/td>\n<td>350 Pa<\/td>\n<td>380 Pa<\/td>\n<td>420 Pa<\/td>\n<\/tr>\n<tr>\n<td>Noise (max)<\/td>\n<td>54 dB(A)<\/td>\n<td>48 dB(A)<\/td>\n<td>45 dB(A)<\/td>\n<\/tr>\n<tr>\n<td>Voltage<\/td>\n<td>48V DC<\/td>\n<td>48V DC<\/td>\n<td>48V DC<\/td>\n<\/tr>\n<tr>\n<td>Control<\/td>\n<td>4-pin PWM<\/td>\n<td>4-pin PWM<\/td>\n<td>4-pin PWM<\/td>\n<\/tr>\n<tr>\n<td>MTBF<\/td>\n<td>\u226550,000 h<\/td>\n<td>\u226550,000 h<\/td>\n<td>\u226550,000 h<\/td>\n<\/tr>\n<tr>\n<td>Best CDU Size<\/td>\n<td>15\u201330 kW<\/td>\n<td>40\u201360 kW<\/td>\n<td>60\u2013100 kW<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>CDU Fan Configuration for AI GPU Clusters<\/h2>\n<p>AI GPU clusters (NVIDIA DGX SuperPOD, Meta RSC) typically use CDU stations sized at 100\u2013200 kW per unit. For a 100 kW air-cooled CDU:<\/p>\n<ul>\n<li>Using 120\u00d738mm fans (140 CFM each): 6 fans + 2 spare = 8-fan array<\/li>\n<li>Using 120\u00d725mm fans (110 CFM each): 8 fans + 2 spare = 10-fan array<\/li>\n<li>Using 92\u00d725mm fans (80 CFM each): 12 fans + 4 spare = 16-fan array<\/li>\n<\/ul>\n<p>For large installations, 172\u00d751mm fans (280\u2013350 CFM each) provide even higher airflow per unit and are recommended for CDU stations above 100 kW \u2014 see the <a href=\"\/48v-dc-cooling-fans-ai-computing-racks\/\">48V DC cooling fans guide<\/a> for larger format options.<\/p>\n<div style=\"background:#f0f6ff;border-left:4px solid #2E75B6;padding:20px 24px;margin:32px 0;border-radius:4px;\">\n<h3 style=\"margin:0 0 8px;color:#1F3864;\">CDU Fan Samples from Fengheng Technology<\/h3>\n<p>92mm and 120mm CDU fans with 48V DC input, PWM control, and MTBF \u226550,000h. Custom configurations available. Sample lead time 2 weeks. <a href=\"mailto:fengheng@adc-coolingfan.com\">Contact fengheng@adc-coolingfan.com<\/a> or <a href=\"\/ai-liquid-cooling\/\">view full portfolio \u2192<\/a><\/p>\n<\/div>\n<h2>Related Technical Guides<\/h2>\n<ul>\n<li><a href=\"\/ai-server-liquid-cooling-fans\/\">Do AI Servers Still Need Cooling Fans in Liquid Cooling Systems?<\/a><\/li>\n<li><a href=\"\/rdhx-fan-selection-guide-static-pressure-airflow\/\">RDHx Fan Selection: Static Pressure vs Airflow<\/a><\/li>\n<li><a href=\"\/48v-dc-cooling-fans-ai-computing-racks\/\">48V DC Cooling Fans for OCP Open Rack v3<\/a><\/li>\n<li><a href=\"\/gpu-liquid-cooling-auxiliary-fan-mtbf-selection\/\">GPU Liquid Cooling Auxiliary Fan MTBF Selection<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>CDU Fan Selection: The 92mm vs 120mm Decision Coolant D [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2471","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"acf":[],"_links":{"self":[{"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/posts\/2471","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/comments?post=2471"}],"version-history":[{"count":5,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/posts\/2471\/revisions"}],"predecessor-version":[{"id":2503,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/posts\/2471\/revisions\/2503"}],"wp:attachment":[{"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/media?parent=2471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/categories?post=2471"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/szfengheng.com\/fr\/wp-json\/wp\/v2\/tags?post=2471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}