{"id":4568,"date":"2026-09-01T23:52:55","date_gmt":"2026-09-02T06:52:55","guid":{"rendered":"https:\/\/www.26yc.com\/plate-heat-exchanger-frost-protection\/"},"modified":"2026-10-09T17:56:59","modified_gmt":"2026-10-10T00:56:59","slug":"plate-heat-exchanger-frost-protection","status":"publish","type":"post","link":"https:\/\/www.26yc.com\/de\/plate-heat-exchanger-frost-protection\/","title":{"rendered":"Frost Protection for Plate Heat Exchangers"},"content":{"rendered":"<p>In cold-climate ventilation, an exhaust-to-supply air-to-air plate exchanger can frost on the exhaust side when the supply outlet drops below the dew point of the humid exhaust. Frost narrows the channels, raises pressure drop and eventually blocks the core. Knowing when it forms &mdash; and which protection strategy to use &mdash; keeps the unit efficient through winter.<\/p>\n<h2>When frost actually forms<\/h2>\n<p>Frost needs two things: sub-freezing supply temperature and moisture in the exhaust. A typical case: exhaust at 20&nbsp;&deg;C and 40% RH, outdoor air at &minus;10&nbsp;&deg;C. As the exhaust cools toward the supply outlet it can reach &minus;5&nbsp;&deg;C, well below freezing, and the condensed moisture ices onto the plates.<\/p>\n<ul>\n<li>Effectiveness above ~70% in deep cold raises frost risk.<\/li>\n<li>High indoor humidity (pools, labs, kitchens) makes it worse.<\/li>\n<li>Frost shows first at the cold corner of the plate pack.<\/li>\n<\/ul>\n<h2>Four protection strategies<\/h2>\n<table>\n<thead>\n<tr>\n<th>Method<\/th>\n<th>How it works<\/th>\n<th>Trade-off<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Preheat supply inlet<\/td>\n<td>Warm outdoor air before the core<\/td>\n<td>Most reliable; uses energy<\/td>\n<\/tr>\n<tr>\n<td>Exhaust bypass \/ recirculation<\/td>\n<td>Waste part of recovery to keep plates warm<\/td>\n<td>Simple; lowers seasonal effectiveness<\/td>\n<\/tr>\n<tr>\n<td>Periodic defrost (wheels)<\/td>\n<td>Reverse rotation or purge to melt ice<\/td>\n<td>Not for plates; brief loss of recovery<\/td>\n<\/tr>\n<tr>\n<td>Heat-pipe assist<\/td>\n<td>Heat pipe pre-warms supply near the cold corner<\/td>\n<td>Passive; adds cost and depth<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>For a <a href=\"https:\/\/www.26yc.com\/de\/heat-exchanger\/\">plate exchanger<\/a>, preheat at the supply inlet is the standard fix because plates have no moving parts to reverse. A <a href=\"https:\/\/www.26yc.com\/de\/heat-recovery\/\">rotary wheel<\/a> can instead use a purge and periodic defrost cycle.<\/p>\n<h2>Sizing margin<\/h2>\n<p>Size the core for the design winter temperature, then add 10&ndash;15% face area so the bypass or preheat strategy has room to work without starving airflow. Our <a href=\"https:\/\/www.26yc.com\/de\/plate-heat-exchangers-guide-en\/\">sizing guide<\/a> walks through the calculation, and the <a href=\"https:\/\/www.26yc.com\/de\/commercial-kitchen-heat-recovery\/\">kitchen recovery<\/a> example shows the same logic on a warm-side load.<\/p>\n<div style=\"background:#f0f4fa;border-left:4px solid #235294;padding:18px 20px;border-radius:8px;margin:24px 0\">\n<h3 style=\"margin:0 0 8px\">Designing a cold-climate exchanger?<\/h3>\n<p style=\"margin:0 0 14px\">EN159 supplies plate, rotary, heat-pipe and counterflow air-to-air exchangers with frost-protection options sized to your winter design conditions. Send outdoor and exhaust temperatures, humidity and airflow.<\/p>\n<p><a href=\"https:\/\/www.26yc.com\/de\/contact-us\/\" style=\"display:inline-block;background:#235294;color:#fff;padding:10px 20px;border-radius:6px;font-weight:700;text-decoration:none\">Angebot anfordern<\/a>\n<\/div>\n<h2>Related reading<\/h2>\n<p>\n<a href=\"https:\/\/www.26yc.com\/de\/heat-exchanger\/\">Air-to-Air Heat Exchangers<\/a> &middot;<br \/>\n<a href=\"https:\/\/www.26yc.com\/de\/heat-recovery\/\">Heat Recovery Units<\/a> &middot;<br \/>\n<a href=\"https:\/\/www.26yc.com\/de\/plate-heat-exchangers-guide-en\/\">Plate Heat Exchanger Guide<\/a>\n<\/p>\n<h2>Frequently Asked Questions<\/h2>\n<p><strong>Why does frost form on a plate heat exchanger?<\/strong><br \/>Frost forms when the supply outlet temperature drops below the freezing point of the moisture in the humid exhaust, condensing and then freezing on the cold plates until the channels narrow or block.<\/p>\n<p><strong>What frost-protection strategies are used?<\/strong><br \/>Common methods are preheating the incoming air, recirculating a portion of warm supply air, modulating or bypassing the exchanger at low outdoor temperatures, and using a defrost cycle on the exhaust side.<\/p>\n<p><strong>How should a unit be sized for cold climates?<\/strong><br \/>Size the core and the frost-control strategy for the design winter condition, checking the supply outlet temperature against the exhaust dew point so the chosen method keeps channels clear.<\/p>\n<p><strong>Does frost protection hurt efficiency?<\/strong><br \/>It trades a little recovered heat for reliability; a well-tuned bypass or preheat holds effectiveness high through most of the season while preventing blockage during the coldest hours.<\/p>\n<div class=\"yc-related\">\n<h3>Verwandte Artikel<\/h3>\n<ul>\n<li><a href=\"https:\/\/www.26yc.com\/de\/heat-pipe-heat-exchanger-working-principle\/\" title=\"How Heat Pipe Heat Exchangers Work: Passive, No-Moving-Parts Recovery\">How Heat Pipe Heat Exchangers Work: Passive, No-Moving-Parts Recovery<\/a><\/li>\n<li><a href=\"https:\/\/www.26yc.com\/de\/customizable-hydrophilic-aluminum-foil-plate-heat-exchanger-fresh-air-unit-for-boiler-exhaust-white-plume-reduction\/\" title=\"Customizable Hydrophilic Aluminum Foil Plate Heat Exchanger \u2014 Fresh Air Unit for Boiler Exhaust White Plume Reduction\">Customizable Hydrophilic Aluminum Foil Plate Heat Exchanger \u2014 Fresh Air Unit for Boiler Exhaust White Plume Reduction<\/a><\/li>\n<\/ul>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>In cold-climate ventilation, an exhaust-to-supply air-to-air plate exchanger can frost on the exhaust side when the supply outlet drops below the dew point of the humid exhaust. Frost narrows the channels, raises pressure drop and eventually blocks the core. Knowing when it forms &mdash; and which protection strategy to use &mdash; keeps the unit efficient [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[71],"tags":[183,236,215,175],"class_list":["post-4568","post","type-post","status-publish","format-standard","hentry","category-heat-exchanger","tag-air-to-air","tag-cold-climate","tag-frost-protection","tag-plate-heat-exchanger"],"_links":{"self":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/posts\/4568","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/comments?post=4568"}],"version-history":[{"count":3,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/posts\/4568\/revisions"}],"predecessor-version":[{"id":5288,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/posts\/4568\/revisions\/5288"}],"wp:attachment":[{"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/media?parent=4568"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/categories?post=4568"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.26yc.com\/de\/wp-json\/wp\/v2\/tags?post=4568"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}