Heat-Pipe Tube Count for 100L, 300L and 500L Tanks | SOLETKS<\/title><br \/>\n<meta name=\"description\" content=\"Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction.\">\n<link rel=\"canonical\" href=\"https:\/\/service.soletksolar.com\/heat-pipe-tube-count-by-tank-capacity\/\">\n<meta property=\"og:type\" content=\"article\"><br \/>\n<meta property=\"og:title\" content=\"Heat-Pipe Tube Count by Tank Capacity: Why 100L, 300L and 500L Configurations Differ\"><br \/>\n<meta property=\"og:description\" content=\"Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction.\"><br \/>\n<meta property=\"og:image\" content=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\"><br \/>\n<meta property=\"og:url\" content=\"https:\/\/service.soletksolar.com\/heat-pipe-tube-count-by-tank-capacity\/\"><br \/>\n<meta name=\"robots\" content=\"max-image-preview:large\">\n<link rel=\"icon\" href=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/cropped-211bdff6-75d9-4868-ba26-75265dcd448d-32x32.png\" sizes=\"32x32\">\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=Inter:wght@400;500;600;700;800&family=Outfit:wght@600;700;800&display=swap\" rel=\"stylesheet\">\n<p><script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"Article\",\n \"headline\": \"Heat-Pipe Tube Count by Tank Capacity: Why 100L, 300L and 500L Configurations Differ\",\n \"description\": \"Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction.\",\n \"image\": \"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\",\n \"datePublished\": \"2026-09-01\",\n \"dateModified\": \"2026-09-03\",\n \"author\": { \"@type\": \"Organization\", \"name\": \"SOLETKS Engineering Team\", \"url\": \"https:\/\/service.soletksolar.com\" },\n \"reviewedBy\": { \"@type\": \"Person\", \"name\": \"Dav\", \"jobTitle\": \"Product Engineering\" },\n \"publisher\": {\n \"@type\": \"Organization\",\n \"name\": \"Shandong Soletks Solar Technology Co., Ltd.\",\n \"logo\": { \"@type\": \"ImageObject\", \"url\": \"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/cropped-211bdff6-75d9-4868-ba26-75265dcd448d.png\" }\n },\n \"mainEntityOfPage\": \"https:\/\/service.soletksolar.com\/heat-pipe-tube-count-by-tank-capacity\/\"\n}\n<\/script><br \/>\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"BreadcrumbList\",\n \"itemListElement\": [\n {\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/service.soletksolar.com\/\"},\n {\"@type\":\"ListItem\",\"position\":2,\"name\":\"Blog\",\"item\":\"https:\/\/service.soletksolar.com\/category\/blog\/\"},\n {\"@type\":\"ListItem\",\"position\":3,\"name\":\"Heat-Pipe Tube Count by Tank Capacity\",\"item\":\"https:\/\/service.soletksolar.com\/heat-pipe-tube-count-by-tank-capacity\/\"}\n ]\n}\n<\/script><br \/>\n<script type=\"application\/ld+json\">\n{\n \"@context\": \"https:\/\/schema.org\",\n \"@type\": \"FAQPage\",\n \"mainEntity\": [\n {\"@type\":\"Question\",\"name\":\"How many heat-pipe tubes are needed for a 100L solar water heater?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"One published SolarMaster system uses a single 10-tube collector for 100L. That is a manufacturer-specific configuration, not a universal requirement. Confirm tube size, aperture area, tested output, climate and target solar fraction.\"}},\n {\"@type\":\"Question\",\"name\":\"How many tubes are needed for a 300L tank?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The reviewed manufacturer tables publish 30 tubes from SolarMaster and Zantia, and 36 tubes across two collectors from JinYi. A project-specific calculation must decide which performance level is appropriate.\"}},\n {\"@type\":\"Question\",\"name\":\"How many tubes are needed for a 500L tank?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The reviewed tables publish either 50 tubes across two 25-tube collectors or 60 tubes across two 30-tube collectors. The correct choice depends on collector performance, solar resource, temperature lift, system loss and solar-fraction target.\"}},\n {\"@type\":\"Question\",\"name\":\"Does SOLETKS recommend 10, 30 and 50 tubes for 100L, 300L and 500L?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No verified SOLETKS capacity-to-HPC table is currently published. SOLETKS publishes HPC collectors with 12, 16, 20, 25 and 30 tubes and provides area and output data by model. A system proposal should select those models from the project load.\"}},\n {\"@type\":\"Question\",\"name\":\"Is a higher tube count always better?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. More tubes can increase collector area within the same product family, but cross-brand comparison requires tested aperture area, efficiency, heat loss and output. 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22px;background:#f1f5f9;border-left:4px solid var(--blue-1);border-radius:0 var(--radius-sm) var(--radius-sm) 0;color:var(--muted-2);font-size:14.7px;}\n<\/style>\n<p><\/head><br \/>\n<body><\/p>\n<p><\/p>\n<div class=\"breadcrumb\">\n<div class=\"container\">\n <a href=\"https:\/\/service.soletksolar.com\/\">Home<\/a> \u203a <br \/>\n <a href=\"https:\/\/service.soletksolar.com\/category\/blog\/\">Blog<\/a> \u203a <br \/>\n <a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">HPC Heat Pipe Solar Collector<\/a> \u203a <br \/>\n <span>Tube Count by Tank Capacity<\/span>\n <\/div>\n<\/div>\n<p><\/p>\n<section class=\"hero\">\n<div class=\"container\">\n<div class=\"hero-content\">\n <span class=\"eyebrow\">Specification Comparison \u00b7 Heat-Pipe Systems<\/span><\/p>\n<h1>Heat-Pipe Tube Count by Tank Capacity: Why <span class=\"accent\">100L, 300L and 500L<\/span> Configurations Differ<\/h1>\n<p class=\"lead\">Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction \u2014 not by tube count alone.<\/p>\n<div class=\"meta-row\">\n <span>By <b>SOLETKS Engineering Team<\/b><\/span><br \/>\n <span>Reviewed by <b>Dav \u00b7 Product Engineering<\/b><\/span><br \/>\n <span>Prepared <b>2026-09-01<\/b><\/span><br \/>\n <span>Audience: <b>Distributors \u00b7 OEM Buyers \u00b7 MEP Engineers<\/b><\/span>\n <\/div>\n<div class=\"btn-group\">\n <a class=\"btn btn-primary\" href=\"https:\/\/service.soletksolar.com\/contact\/\">Request a Load-Based Proposal<\/a><br \/>\n <a class=\"btn btn-ghost\" href=\"#comparison\">See the Manufacturer Comparison \u2193<\/a>\n <\/div>\n<\/p><\/div>\n<div class=\"hero-image\">\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"Vacuum tube heat pipe solar collector array used for tank sizing comparison\"><\/p>\n<div class=\"cap\">Evacuated-tube heat-pipe collector array \u2014 tube count is a physical configuration detail, not a substitute for an energy-load calculation.<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n<p><\/p>\n<div class=\"toc-wrap\">\n<div class=\"container\">\n <span class=\"toc-label\">On this page<\/span><br \/>\n <a href=\"#comparison\">Manufacturer Comparison<\/a><br \/>\n <a href=\"#why-not\">Why Capacity \u2260 Tube Count<\/a><br \/>\n <a href=\"#soletks-hpc\">SOLETKS HPC Range<\/a><br \/>\n <a href=\"#method\">Two-Stage Method<\/a><br \/>\n <a href=\"#certs\">Certification Notes<\/a><br \/>\n <a href=\"#procurement\">Procurement Table<\/a><br \/>\n <a href=\"#mistakes\">Common Mistakes<\/a><br \/>\n <a href=\"#faq\">FAQ<\/a>\n <\/div>\n<\/div>\n<p><main><\/p>\n<div class=\"container article-body\">\n<div class=\"answer-box\">\n <span class=\"tag\">Quick Answer<\/span><\/p>\n<p>There is <strong>no universal rule<\/strong> that a 100L solar tank needs 10 heat-pipe tubes, a 300L tank needs 30, or a 500L tank needs 50. Those are real configurations published by one manufacturer, but other manufacturers publish 36 tubes for 300L and 60 tubes for 500L.<\/p>\n<p>The correct sequence is to calculate the hot-water energy load, choose a target solar fraction for the project location, select a collector from tested area and thermal-performance data, and only then confirm how many tubes that collector contains.<\/p>\n<\/p><\/div>\n<p>This distinction matters in procurement. A tube is not a standardized unit of useful heat. Tube diameter, length, absorber construction, aperture area, efficiency curve, manifold loss, operating temperature and complete-system design can all differ. Comparing quotations only by tube count can reward the wrong system.<\/p>\n<h2 id=\"comparison\">Direct Answer: What Three Manufacturers Actually Publish<\/h2>\n<p>The table below compares complete, forced-circulation heat-pipe system configurations published by SolarMaster, JinYi and Zantia. It is evidence of market variation, not a recommendation to copy any one row.<\/p>\n<div class=\"table-wrap highlight\">\n<table>\n<caption>Published heat-pipe tube counts by nominal tank capacity<\/caption>\n<thead>\n<tr>\n<th>Nominal tank capacity<\/th>\n<th>SolarMaster<\/th>\n<th>JinYi<\/th>\n<th>Zantia<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>100L<\/strong><\/td>\n<td>10 tubes \u00d7 1 collector<\/td>\n<td>Not listed<\/td>\n<td>Not listed<\/td>\n<\/tr>\n<tr>\n<td><strong>150L<\/strong><\/td>\n<td>15 tubes \u00d7 1<\/td>\n<td>18 tubes \u00d7 1<\/td>\n<td>Not listed<\/td>\n<\/tr>\n<tr>\n<td><strong>200L<\/strong><\/td>\n<td>20 tubes \u00d7 1<\/td>\n<td>24 tubes \u00d7 1<\/td>\n<td>20 tubes \u00d7 1<\/td>\n<\/tr>\n<tr>\n<td><strong>300L<\/strong><\/td>\n<td>30 tubes \u00d7 1<\/td>\n<td>36 tubes \/ 2 collectors<\/td>\n<td>30 tubes \u00d7 1<\/td>\n<\/tr>\n<tr>\n<td><strong>500L<\/strong><\/td>\n<td>25 tubes \u00d7 2 = 50<\/td>\n<td>60 tubes \/ 2 collectors<\/td>\n<td>30 tubes \u00d7 2 = 60<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<div class=\"mfg-grid\">\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">SolarMaster<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>10 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>30 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>50 tubes (2\u00d725)<\/b><\/div>\n<\/p><\/div>\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">JinYi<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>Not listed<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>36 tubes (2 units)<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>60 tubes (2 units)<\/b><\/div>\n<\/p><\/div>\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">Zantia<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>Not listed<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>30 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>60 tubes (2\u00d730)<\/b><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<p>At 300L, the published range is <strong>30\u201336 tubes<\/strong>, a 20% difference relative to 30. At 500L, it is <strong>50\u201360 tubes<\/strong>, also a 20% difference relative to 50. If litres alone determined the answer, those differences should not exist.<\/p>\n<div class=\"note-box\">\n<div class=\"icon\">!<\/div>\n<div class=\"text\">\n<p><strong>Important:<\/strong> each row belongs to that manufacturer’s own collector, tank, heat exchanger, pump station and design assumptions. Do not combine one company’s tank with another company’s tube-count table without recalculating the system.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<h2 id=\"why-not\">Why Tank Capacity Cannot Determine Tube Count by Itself<\/h2>\n<h3>1. Tube dimensions are not always the same<\/h3>\n<p>Twenty tubes of one diameter and length do not necessarily have the same absorber or aperture area as twenty tubes from another series. Even when the external dimensions look similar, the absorber coating, vacuum quality, heat-pipe condenser and manifold interface can change performance.<\/p>\n<p>Start by comparing: tube outside diameter and length, number of tubes, collector gross area, aperture or lighting area, certified efficiency parameters, heat-loss coefficient, and specified output at stated test conditions. If a quotation lists only “30 tubes” and no area or tested performance, it is incomplete.<\/p>\n<h3>2. The same tank can serve a different heat load<\/h3>\n<p>A 300L tank in a warm climate with 25\u00b0C mains water requires less energy to reach 55\u00b0C than the same tank with 5\u00b0C incoming water. A hotel preheating tank, a villa cylinder and a process-water buffer may also have completely different draw schedules.<\/p>\n<div class=\"formula-box\">\n <span class=\"fx-label\">Daily Heat Load Formula<\/span><br \/>\n Daily heat load (kWh) = water volume (L) \u00d7 temperature rise (\u00b0C) \u00d7 4.186 \u00f7 3,600\n <\/div>\n<div class=\"table-wrap\">\n<table>\n<caption>Ideal heat added to the water (40\u00b0C rise, once per day)<\/caption>\n<thead>\n<tr>\n<th>Tank volume<\/th>\n<th>Assumed temperature rise<\/th>\n<th>Ideal heat added<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>100L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>4.65 kWh<\/strong><\/td>\n<\/tr>\n<tr>\n<td>300L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>13.95 kWh<\/strong><\/td>\n<\/tr>\n<tr>\n<td>500L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>23.26 kWh<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>These figures exclude tank loss, piping loss, heat-exchanger approach, draw profile and control losses. Their purpose is to show why an energy calculation is required before a tube count.<\/p>\n<h3>3. Buyers choose different solar fractions<\/h3>\n<p>One project may ask solar thermal to cover 30% of the annual hot-water load; another may target 60% or more. The U.S. Department of Energy’s Federal Energy Management Program calculator explicitly sizes solar hot-water systems from solar resource and the percentage of load to be met.<\/p>\n<p>A larger solar fraction normally requires more collector capacity, but oversizing for the best month can create summer stagnation and poor economics. The design must examine monthly demand and solar availability, not only an annual average.<\/p>\n<h3>4. Collector output changes with operating conditions<\/h3>\n<p>Published peak or specified power is tied to test conditions. Actual useful output changes with: solar irradiance, ambient temperature, collector inlet temperature, flow rate, tilt and orientation, shading and soiling, wind, pipe and manifold loss, heat-exchanger performance, and storage temperature and stratification.<\/p>\n<p>A 30-tube collector operating with cold return fluid on a clear day is not equivalent to the same collector trying to maintain a high storage temperature in cold wind.<\/p>\n<h3>5. Complete-system architecture changes the pairing<\/h3>\n<p>The number of tanks, number of coils, collector banks, hydraulic layout, expansion vessel, controller and backup source all influence the final system. JinYi’s published 300L configuration uses two collectors and 36 tubes; SolarMaster and Zantia publish a single 30-tube collector for 300L. At 500L, all three use multiple collector modules, but the total count still varies.<\/p>\n<p>This is why a capacity-to-tube table is useful for market comparison but unsafe as a universal design chart.<\/p>\n<h2 id=\"soletks-hpc\">What SOLETKS Currently Publishes for Its HPC Collectors<\/h2>\n<p>SOLETKS’ HPC technical guide publishes five heat-pipe collector models. The verified table below compares each collector as a <strong>component<\/strong>; it does not assign a tank capacity to any model.<\/p>\n<div class=\"img-card\">\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"SOLETKS HPC evacuated tube heat pipe solar collector component\"><figcaption>SOLETKS HPC range uses \u03a658 \u00d7 1,800mm evacuated tubes across five models \u2014 physical tube count differs from any tank-capacity claim.<\/figcaption><\/div>\n<div class=\"hpc-strip\">\n<div class=\"hpc-model\">\n<div class=\"name\">HPC182<\/div>\n<div class=\"tubes\">12<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">1.20m\u00b2 \u00b7 0.72kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC240<\/div>\n<div class=\"tubes\">16<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">1.60m\u00b2 \u00b7 0.96kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC298<\/div>\n<div class=\"tubes\">20<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">2.00m\u00b2 \u00b7 1.20kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC370<\/div>\n<div class=\"tubes\">25<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">2.50m\u00b2 \u00b7 1.50kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC442<\/div>\n<div class=\"tubes\">30<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">3.00m\u00b2 \u00b7 1.80kW<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div class=\"table-wrap\">\n<table>\n<caption>SOLETKS HPC model, tube count and specified power (at 1,000W\/m\u00b2)<\/caption>\n<thead>\n<tr>\n<th>SOLETKS HPC model<\/th>\n<th>Vacuum tubes<\/th>\n<th>Lighting area<\/th>\n<th>Specified power<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>HPC182<\/td>\n<td>12<\/td>\n<td>1.20m\u00b2<\/td>\n<td>0.72kW<\/td>\n<\/tr>\n<tr>\n<td>HPC240<\/td>\n<td>16<\/td>\n<td>1.60m\u00b2<\/td>\n<td>0.96kW<\/td>\n<\/tr>\n<tr>\n<td>HPC298<\/td>\n<td>20<\/td>\n<td>2.00m\u00b2<\/td>\n<td>1.20kW<\/td>\n<\/tr>\n<tr>\n<td>HPC370<\/td>\n<td>25<\/td>\n<td>2.50m\u00b2<\/td>\n<td>1.50kW<\/td>\n<\/tr>\n<tr>\n<td>HPC442<\/td>\n<td>30<\/td>\n<td>3.00m\u00b2<\/td>\n<td>1.80kW<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>The published range uses \u03a658 \u00d7 1,800mm evacuated tubes, has a 0.6MPa working pressure and a 120\u00b0C maximum operating temperature. The guide also lists a peak efficiency of 0.724 and a total heat-loss coefficient of 2.453W\/(m\u00b2\u00b7K).<\/p>\n<p>Those values allow a qualified designer to compare models and build a collector field. The 1,000W\/m\u00b2 power row is an instantaneous test-condition reference, not a daily-energy promise. Daily and annual yield still require local irradiation, temperature and loss inputs.<\/p>\n<div class=\"note-box\">\n<div class=\"icon\">\u2715<\/div>\n<div class=\"text\">\n<p><strong>Most importantly:<\/strong> SOLETKS does not currently publish a verified table saying 100L = a specific HPC model or quantity, 300L = a specific HPC model or quantity, or 500L = a specific HPC model or quantity. Until such a table is issued and technically approved, buyers should request a project calculation rather than treat a competitor’s 10\/30\/50 pattern as a SOLETKS recommendation.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<h2 id=\"method\">A Two-Stage Method for Choosing the Collector<\/h2>\n<div class=\"stage-grid\">\n<div class=\"stage-card stage1\">\n<div class=\"stage-num\">1<\/div>\n<h3>Define the Thermal Requirement<\/h3>\n<ol>\n<li>Project location and monthly solar resource<\/li>\n<li>Daily hot-water volume and busiest-hour draw<\/li>\n<li>Cold-water temperature by season<\/li>\n<li>Required storage and delivery temperatures<\/li>\n<li>Target monthly or annual solar fraction<\/li>\n<li>Tank, pipe, recirculation and heat-exchanger losses<\/li>\n<li>Backup-heater type, capacity and operating window<\/li>\n<\/ol><\/div>\n<div class=\"stage-card stage2\">\n<div class=\"stage-num\">2<\/div>\n<h3>Select Tested Collector Area & Quantity<\/h3>\n<ol>\n<li>Use aperture or lighting area consistently<\/li>\n<li>Use the certified efficiency curve at expected conditions<\/li>\n<li>Estimate useful monthly energy, including losses<\/li>\n<li>Check roof area, structural load, wind, snow, spacing<\/li>\n<li>Check pressure drop, branch balance, pump\/exchanger duty<\/li>\n<li>Confirm stagnation, freeze protection, expansion volume<\/li>\n<li>Convert the selected model and quantity into a tube count<\/li>\n<\/ol><\/div>\n<\/p><\/div>\n<p>Calculate the hot-water energy load and the portion intended to come from solar. For commercial work, use a time series or recognized simulation method rather than one daily average.<\/p>\n<div class=\"example-box\">\n<h4>Worked example \u2014 SOLETKS HPC442 concept estimate<\/h4>\n<p>Daily hot water: 5,000L \u00b7 Cold inlet: 15\u00b0C \u00b7 Target preheat: 50\u00b0C \u00b7 Temperature rise: 35\u00b0C<\/p>\n<div class=\"calc-step\">Daily heat demand = 5,000 \u00d7 35 \u00d7 0.001163 = <strong>203.5 kWh\/day<\/strong><\/div>\n<div class=\"calc-step\">Solar target (40% fraction) = 203.5 \u00d7 40% = <strong>81.4 kWh\/day<\/strong><\/div>\n<div class=\"calc-step\">HPC442 at 700W\/m\u00b2 \u00d7 4 useful hours \u2248 <strong>4.6 kWh\/day per collector<\/strong><\/div>\n<div class=\"calc-step\">81.4 \u00f7 4.6 \u2248 <strong>18 HPC442 collectors<\/strong> (before losses & safety factors)<\/div>\n<p style=\"margin-top:12px;font-size:13px;\">This is only an early concept estimate. Final sizing must consider local irradiation, seasonality, tilt, pipe loss, tank size, backup heating, operating temperature, pump strategy and solar-fraction target.<\/p>\n<\/p><\/div>\n<p>This method may produce 30, 36, 50 or 60 tubes for a system in the capacities discussed here. The defensible answer is the one tied to stated inputs and tested performance.<\/p>\n<h2 id=\"certs\">What Certifications Can and Cannot Tell You<\/h2>\n<p>Solar Keymark distinguishes certified solar collectors, factory-made systems and custom-built systems. That distinction matters because a certified collector result does not automatically certify every tank-and-collector combination assembled around it.<\/p>\n<p>Ask the supplier to identify:<\/p>\n<ul>\n<li>the exact certified product or family<\/li>\n<li>whether the certificate applies to the collector, the factory-made system or both<\/li>\n<li>the tested aperture area and performance parameters<\/li>\n<li>whether the quoted tank\/collector combination is included<\/li>\n<li>the current certificate and test-report revision<\/li>\n<\/ul>\n<p>Certification supports comparable performance evidence. It does not eliminate the need for site sizing, hydraulic design or local code review.<\/p>\n<h2 id=\"procurement\">A Procurement Comparison That Is Better Than “Price per Tube”<\/h2>\n<p>Use a normalized quotation table:<\/p>\n<div class=\"table-wrap\">\n<table>\n<thead>\n<tr>\n<th>Procurement field<\/th>\n<th>Why it is required<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Tank model & actual usable volume<\/strong><\/td>\n<td>Nominal litres may not equal drawdown volume<\/td>\n<\/tr>\n<tr>\n<td><strong>Collector model & quantity<\/strong><\/td>\n<td>Links the quote to a verified product<\/td>\n<\/tr>\n<tr>\n<td><strong>Tube diameter, length & count<\/strong><\/td>\n<td>Confirms the physical configuration<\/td>\n<\/tr>\n<tr>\n<td><strong>Gross & aperture\/lighting area<\/strong><\/td>\n<td>Enables like-for-like area comparison<\/td>\n<\/tr>\n<tr>\n<td><strong>Efficiency curve & heat-loss coefficient<\/strong><\/td>\n<td>Supports output calculations beyond peak efficiency<\/td>\n<\/tr>\n<tr>\n<td><strong>Specified output with test conditions<\/strong><\/td>\n<td>Prevents an unqualified power claim<\/td>\n<\/tr>\n<tr>\n<td><strong>System or collector certificate<\/strong><\/td>\n<td>Shows what was independently evaluated<\/td>\n<\/tr>\n<tr>\n<td><strong>Heat-exchanger type & area<\/strong><\/td>\n<td>Confirms that collector heat can enter the tank<\/td>\n<\/tr>\n<tr>\n<td><strong>Pump, design flow & pressure drop<\/strong><\/td>\n<td>Supports hydraulic performance<\/td>\n<\/tr>\n<tr>\n<td><strong>Expansion vessel & safety valves<\/strong><\/td>\n<td>Supports closed-loop safety<\/td>\n<\/tr>\n<tr>\n<td><strong>Backup heater & recovery time<\/strong><\/td>\n<td>Shows how demand is met when solar is insufficient<\/td>\n<\/tr>\n<tr>\n<td><strong>Freeze & stagnation strategy<\/strong><\/td>\n<td>Protects the system at both temperature extremes<\/td>\n<\/tr>\n<tr>\n<td><strong>Monthly energy estimate & assumptions<\/strong><\/td>\n<td>Makes solar-fraction claims auditable<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>Price should be compared only after these fields are aligned. A system with fewer tubes may have a larger effective area or stronger tested output; a system with more tubes may be compensating for a smaller collector module or a more demanding design target.<\/p>\n<h2 id=\"mistakes\">Common Mistakes When Interpreting Tube-Count Tables<\/h2>\n<div class=\"mistake-grid\">\n<div class=\"mistake-card\">\n<div class=\"num\">1<\/div>\n<h4>Treating litres per tube as a physical constant<\/h4>\n<p>“Ten litres per tube” is a product-family pattern, not a law of solar thermal design. It does not replace an energy balance.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">2<\/div>\n<h4>Comparing heat-pipe and direct-flow systems by count<\/h4>\n<p>Collector construction and fluid path differ. Keep the comparison within the same technology class and use tested area and output.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">3<\/div>\n<h4>Ignoring the number of collector modules<\/h4>\n<p>A 500L row may say “50 tubes,” but the physical system can be two 25-tube collectors, affecting piping and layout.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">4<\/div>\n<h4>Using peak power as daily energy<\/h4>\n<p>Kilowatts describe power at a moment. Kilowatt-hours describe energy over time. Daily yield requires irradiance and condition data.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">5<\/div>\n<h4>Assuming a competitor configuration is a SOLETKS configuration<\/h4>\n<p>The comparison table documents how other manufacturers package systems \u2014 it does not fill the missing SOLETKS capacity-to-HPC mapping.<\/p>\n<\/div><\/div>\n<h2 id=\"faq\">Frequently Asked Questions<\/h2>\n<details class=\"faq-item\" open>\n<summary>How many heat-pipe tubes are needed for a 100L solar water heater?<\/summary>\n<div class=\"faq-body\">One published SolarMaster system uses a single 10-tube collector for 100L. That is a manufacturer-specific configuration, not a universal requirement. Confirm tube size, aperture area, tested output, climate and target solar fraction.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>How many tubes are needed for a 300L tank?<\/summary>\n<div class=\"faq-body\">The reviewed manufacturer tables publish 30 tubes from SolarMaster and Zantia, and 36 tubes across two collectors from JinYi. A project-specific calculation must decide which performance level is appropriate.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>How many tubes are needed for a 500L tank?<\/summary>\n<div class=\"faq-body\">The reviewed tables publish either 50 tubes across two 25-tube collectors or 60 tubes across two 30-tube collectors. The correct choice depends on collector performance, solar resource, temperature lift, system loss and solar-fraction target.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>Does SOLETKS recommend 10, 30 and 50 tubes for 100L, 300L and 500L?<\/summary>\n<div class=\"faq-body\">No verified SOLETKS capacity-to-HPC table is currently published. SOLETKS publishes HPC collectors with 12, 16, 20, 25 and 30 tubes and provides area and output data by model. A system proposal should select those models from the project load.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>Is a higher tube count always better?<\/summary>\n<div class=\"faq-body\">No. More tubes can increase collector area within the same product family, but cross-brand comparison requires tested aperture area, efficiency, heat loss and output. Excess collector capacity can also increase stagnation risk.<\/div>\n<\/details>\n<p> <\/p>\n<div class=\"cta-band\">\n<h2>Request a Load-Based Heat-Pipe System Proposal<\/h2>\n<p>Send the project location, daily hot-water demand, inlet and target temperatures, load schedule, target solar fraction, roof information and backup source. SOLETKS can then propose the HPC model quantity, storage, heat exchanger, hydraulic components and controls as one engineered system.<\/p>\n<p> <a class=\"btn btn-primary\" href=\"https:\/\/service.soletksolar.com\/contact\/\">Contact SOLETKS Engineering<\/a>\n <\/div>\n<h2>Continue the Heat-Pipe Selection Topic Cluster<\/h2>\n<div class=\"related-grid\">\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"SOLETKS HPC heat pipe solar collector guide\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Component Guide<\/span><\/p>\n<h4>HPC Heat Pipe Solar Collector \u2014 Full Verified Specifications<\/h4>\n<\/p><\/div>\n<p> <\/a><br \/>\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/products\/solar-water-heater\/heat-pipe-solar-water-heater\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Harz-Church-Hot-Water-Project-Germany.png\" alt=\"SOLETKS heat pipe solar water heater integrated product range\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Product Range<\/span><\/p>\n<h4>SOLETKS Heat Pipe Solar Water Heater \u2014 Integrated Product Line<\/h4>\n<\/p><\/div>\n<p> <\/a><br \/>\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/compact-heat-pipe-solar-water-heater\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Florida-Resort-Villa-Hot-Water-Project-USA.png\" alt=\"Compact heat pipe solar water heater cold-climate selection guide\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Cold-Climate Guide<\/span><\/p>\n<h4>Compact Heat Pipe Solar Water Heater: Cold-Climate Selection<\/h4>\n<\/p><\/div>\n<p> <\/a>\n <\/div>\n<p style=\"font-size:14px;\">For verified component data, see the <a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">SOLETKS HPC Heat Pipe Solar Collector Guide<\/a>. For the current integrated-product range, see the <a href=\"https:\/\/service.soletksolar.com\/products\/solar-water-heater\/heat-pipe-solar-water-heater\/\">SOLETKS Heat Pipe Solar Water Heater<\/a>. The existing <a href=\"https:\/\/service.soletksolar.com\/compact-heat-pipe-solar-water-heater\/\">Compact Heat Pipe Solar Water Heater guide<\/a> covers cold-climate selection and remains the destination for that broader intent.<\/p>\n<p> <\/p>\n<h2>Sources<\/h2>\n<ol class=\"sources-list\">\n<li><a href=\"https:\/\/www.solarmastertech.com\/?page_id=20647&post_type=products\" target=\"_blank\" rel=\"noopener\">SolarMaster \u2014 Split Pressurized Solar Water Heater product range<\/a><\/li>\n<li><a href=\"https:\/\/www.jinyi-solar.com\/heat-pipe-solar-water-heating-system.html\" target=\"_blank\" rel=\"noopener\">JinYi \u2014 Heat Pipe Solar Water Heating System<\/a><\/li>\n<li><a href=\"https:\/\/zantia.com\/zantia\/public\/index.php\/climatizacao\/energias-renovaveis\/energia-solar-termica\/kits-solares\/heat-pipe-forced-circulation-kits\" target=\"_blank\" rel=\"noopener\">Zantia \u2014 Heat Pipe Forced-Circulation Kits<\/a><\/li>\n<li><a href=\"https:\/\/www.energy.gov\/cmei\/femp\/articles\/solar-hot-water-system-calculator\" target=\"_blank\" rel=\"noopener\">U.S. Department of Energy FEMP \u2014 Solar Hot Water System Calculator<\/a><\/li>\n<li><a href=\"https:\/\/solarkeymark.eu\/stakeholders\/manufacturers\/\" target=\"_blank\" rel=\"noopener\">Solar Keymark \u2014 Information for Manufacturers<\/a><\/li>\n<li><a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">SOLETKS \u2014 HPC Heat Pipe Solar Collector Guide<\/a><\/li>\n<li><a href=\"https:\/\/service.soletksolar.com\/solar-water-heater-system-for-homes-hotels-and-commercial-projects\/\">SOLETKS \u2014 Solar Water Heater System Design Guide<\/a><\/li>\n<\/ol><\/div>\n<p><\/main><\/p>\n<p><\/body><br \/>\n<\/html><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction.<\/p>","protected":false},"author":1,"featured_media":352,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[16,9],"class_list":["post-1791","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-evacuated-tube-collector","tag-solar-thermal"],"_links":{"self":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts\/1791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/comments?post=1791"}],"version-history":[{"count":0,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts\/1791\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/media\/352"}],"wp:attachment":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/media?parent=1791"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/categories?post=1791"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/tags?post=1791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

{"id":1791,"date":"2026-09-01T00:00:00","date_gmt":"2026-09-01T00:00:00","guid":{"rendered":"https:\/\/service.soletksolar.com\/heat-pipe-tube-count-by-tank-capacity\/"},"modified":"2026-09-01T00:00:00","modified_gmt":"2026-09-01T00:00:00","slug":"heat-pipe-tube-count-by-tank-capacity","status":"publish","type":"post","link":"https:\/\/service.soletksolar.com\/cs\/heat-pipe-tube-count-by-tank-capacity\/","title":{"rendered":"Heat-Pipe Tube Count by Tank Capacity: Why 100L, 300L and 500L Configurations Differ"},"content":{"rendered":"

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20px;color:var(--muted-2);font-size:14.7px;}<\/p>\n<p>\/* CTA band *\/\n.cta-band{background:linear-gradient(135deg,#1e3a8a 0%,#2563eb 100%);border-radius:var(--radius-lg);padding:46px 44px;margin:50px 0;color:#fff;text-align:center;}\n.cta-band h2{color:#fff;margin-top:0;}\n.cta-band h2::before{margin-left:auto;margin-right:auto;background:rgba(255,255,255,.6);}\n.cta-band p{color:rgba(255,255,255,.88);max-width:640px;margin:0 auto 26px;}\n.cta-band .btn-primary{background:#fff;color:var(--blue-2);box-shadow:0 6px 20px rgba(0,0,0,.2);}\n.cta-band .btn-primary:hover{background:#f1f5f9;}<\/p>\n<p>\/* Related grid *\/\n.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin:28px 0 40px;}\n.related-card{background:#fff;border:1px solid var(--card-border);border-radius:var(--radius-md);overflow:hidden;transition:.25s;}\n.related-card:hover{box-shadow:0 12px 30px rgba(15,23,42,.1);transform:translateY(-4px);}\n.related-card 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li{color:#7f1d1d;font-size:14px;margin-bottom:6px;}\n.meta-table{width:100%;font-size:13.5px;border-collapse:collapse;margin:16px 0;}\n.meta-table td{padding:8px 10px;border-bottom:1px solid #f1f5f9;color:var(--muted-2);}\n.meta-table td:first-child{font-weight:600;color:var(--ink);width:220px;}\n.pill-row{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0 4px;}\n.pill{background:#f1f5f9;border-radius:14px;padding:5px 12px;font-size:12.5px;color:var(--muted-2);font-weight:600;}<\/p>\n<p>\/* Sources *\/\n.sources-list{list-style:none;padding:0;counter-reset:src;}\n.sources-list li{counter-increment:src;position:relative;padding:12px 0 12px 40px;border-bottom:1px solid var(--card-border);font-size:14px;color:var(--muted-2);}\n.sources-list li::before{content:'['counter(src)']';position:absolute;left:0;top:12px;color:var(--blue-2);font-weight:700;font-size:13px;}\n.sources-list li:last-child{border-bottom:none;}<\/p>\n<p>blockquote{margin:22px 0;padding:16px 22px;background:#f1f5f9;border-left:4px solid var(--blue-1);border-radius:0 var(--radius-sm) var(--radius-sm) 0;color:var(--muted-2);font-size:14.7px;}\n<\/style>\n<p><\/head><br \/>\n<body><\/p>\n<p><\/p>\n<div class=\"breadcrumb\">\n<div class=\"container\">\n <a href=\"https:\/\/service.soletksolar.com\/\">Home<\/a> \u203a <br \/>\n <a href=\"https:\/\/service.soletksolar.com\/category\/blog\/\">Blog<\/a> \u203a <br \/>\n <a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">HPC Heat Pipe Solar Collector<\/a> \u203a <br \/>\n <span>Tube Count by Tank Capacity<\/span>\n <\/div>\n<\/div>\n<p><\/p>\n<section class=\"hero\">\n<div class=\"container\">\n<div class=\"hero-content\">\n <span class=\"eyebrow\">Specification Comparison \u00b7 Heat-Pipe Systems<\/span><\/p>\n<h1>Heat-Pipe Tube Count by Tank Capacity: Why <span class=\"accent\">100L, 300L and 500L<\/span> Configurations Differ<\/h1>\n<p class=\"lead\">Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction \u2014 not by tube count alone.<\/p>\n<div class=\"meta-row\">\n <span>By <b>SOLETKS Engineering Team<\/b><\/span><br \/>\n <span>Reviewed by <b>Dav \u00b7 Product Engineering<\/b><\/span><br \/>\n <span>Prepared <b>2026-09-01<\/b><\/span><br \/>\n <span>Audience: <b>Distributors \u00b7 OEM Buyers \u00b7 MEP Engineers<\/b><\/span>\n <\/div>\n<div class=\"btn-group\">\n <a class=\"btn btn-primary\" href=\"https:\/\/service.soletksolar.com\/contact\/\">Request a Load-Based Proposal<\/a><br \/>\n <a class=\"btn btn-ghost\" href=\"#comparison\">See the Manufacturer Comparison \u2193<\/a>\n <\/div>\n<\/p><\/div>\n<div class=\"hero-image\">\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"Vacuum tube heat pipe solar collector array used for tank sizing comparison\"><\/p>\n<div class=\"cap\">Evacuated-tube heat-pipe collector array \u2014 tube count is a physical configuration detail, not a substitute for an energy-load calculation.<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n<p><\/p>\n<div class=\"toc-wrap\">\n<div class=\"container\">\n <span class=\"toc-label\">On this page<\/span><br \/>\n <a href=\"#comparison\">Manufacturer Comparison<\/a><br \/>\n <a href=\"#why-not\">Why Capacity \u2260 Tube Count<\/a><br \/>\n <a href=\"#soletks-hpc\">SOLETKS HPC Range<\/a><br \/>\n <a href=\"#method\">Two-Stage Method<\/a><br \/>\n <a href=\"#certs\">Certification Notes<\/a><br \/>\n <a href=\"#procurement\">Procurement Table<\/a><br \/>\n <a href=\"#mistakes\">Common Mistakes<\/a><br \/>\n <a href=\"#faq\">FAQ<\/a>\n <\/div>\n<\/div>\n<p><main><\/p>\n<div class=\"container article-body\">\n<div class=\"answer-box\">\n <span class=\"tag\">Quick Answer<\/span><\/p>\n<p>There is <strong>no universal rule<\/strong> that a 100L solar tank needs 10 heat-pipe tubes, a 300L tank needs 30, or a 500L tank needs 50. Those are real configurations published by one manufacturer, but other manufacturers publish 36 tubes for 300L and 60 tubes for 500L.<\/p>\n<p>The correct sequence is to calculate the hot-water energy load, choose a target solar fraction for the project location, select a collector from tested area and thermal-performance data, and only then confirm how many tubes that collector contains.<\/p>\n<\/p><\/div>\n<p>This distinction matters in procurement. A tube is not a standardized unit of useful heat. Tube diameter, length, absorber construction, aperture area, efficiency curve, manifold loss, operating temperature and complete-system design can all differ. Comparing quotations only by tube count can reward the wrong system.<\/p>\n<h2 id=\"comparison\">Direct Answer: What Three Manufacturers Actually Publish<\/h2>\n<p>The table below compares complete, forced-circulation heat-pipe system configurations published by SolarMaster, JinYi and Zantia. It is evidence of market variation, not a recommendation to copy any one row.<\/p>\n<div class=\"table-wrap highlight\">\n<table>\n<caption>Published heat-pipe tube counts by nominal tank capacity<\/caption>\n<thead>\n<tr>\n<th>Nominal tank capacity<\/th>\n<th>SolarMaster<\/th>\n<th>JinYi<\/th>\n<th>Zantia<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>100L<\/strong><\/td>\n<td>10 tubes \u00d7 1 collector<\/td>\n<td>Not listed<\/td>\n<td>Not listed<\/td>\n<\/tr>\n<tr>\n<td><strong>150L<\/strong><\/td>\n<td>15 tubes \u00d7 1<\/td>\n<td>18 tubes \u00d7 1<\/td>\n<td>Not listed<\/td>\n<\/tr>\n<tr>\n<td><strong>200L<\/strong><\/td>\n<td>20 tubes \u00d7 1<\/td>\n<td>24 tubes \u00d7 1<\/td>\n<td>20 tubes \u00d7 1<\/td>\n<\/tr>\n<tr>\n<td><strong>300L<\/strong><\/td>\n<td>30 tubes \u00d7 1<\/td>\n<td>36 tubes \/ 2 collectors<\/td>\n<td>30 tubes \u00d7 1<\/td>\n<\/tr>\n<tr>\n<td><strong>500L<\/strong><\/td>\n<td>25 tubes \u00d7 2 = 50<\/td>\n<td>60 tubes \/ 2 collectors<\/td>\n<td>30 tubes \u00d7 2 = 60<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<div class=\"mfg-grid\">\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">SolarMaster<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>10 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>30 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>50 tubes (2\u00d725)<\/b><\/div>\n<\/p><\/div>\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">JinYi<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>Not listed<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>36 tubes (2 units)<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>60 tubes (2 units)<\/b><\/div>\n<\/p><\/div>\n<div class=\"mfg-card\">\n<div class=\"mfg-name\">Zantia<\/div>\n<div class=\"mfg-row\"><span>100L<\/span><b>Not listed<\/b><\/div>\n<div class=\"mfg-row\"><span>300L<\/span><b>30 tubes<\/b><\/div>\n<div class=\"mfg-row\"><span>500L<\/span><b>60 tubes (2\u00d730)<\/b><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<p>At 300L, the published range is <strong>30\u201336 tubes<\/strong>, a 20% difference relative to 30. At 500L, it is <strong>50\u201360 tubes<\/strong>, also a 20% difference relative to 50. If litres alone determined the answer, those differences should not exist.<\/p>\n<div class=\"note-box\">\n<div class=\"icon\">!<\/div>\n<div class=\"text\">\n<p><strong>Important:<\/strong> each row belongs to that manufacturer’s own collector, tank, heat exchanger, pump station and design assumptions. Do not combine one company’s tank with another company’s tube-count table without recalculating the system.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<h2 id=\"why-not\">Why Tank Capacity Cannot Determine Tube Count by Itself<\/h2>\n<h3>1. Tube dimensions are not always the same<\/h3>\n<p>Twenty tubes of one diameter and length do not necessarily have the same absorber or aperture area as twenty tubes from another series. Even when the external dimensions look similar, the absorber coating, vacuum quality, heat-pipe condenser and manifold interface can change performance.<\/p>\n<p>Start by comparing: tube outside diameter and length, number of tubes, collector gross area, aperture or lighting area, certified efficiency parameters, heat-loss coefficient, and specified output at stated test conditions. If a quotation lists only “30 tubes” and no area or tested performance, it is incomplete.<\/p>\n<h3>2. The same tank can serve a different heat load<\/h3>\n<p>A 300L tank in a warm climate with 25\u00b0C mains water requires less energy to reach 55\u00b0C than the same tank with 5\u00b0C incoming water. A hotel preheating tank, a villa cylinder and a process-water buffer may also have completely different draw schedules.<\/p>\n<div class=\"formula-box\">\n <span class=\"fx-label\">Daily Heat Load Formula<\/span><br \/>\n Daily heat load (kWh) = water volume (L) \u00d7 temperature rise (\u00b0C) \u00d7 4.186 \u00f7 3,600\n <\/div>\n<div class=\"table-wrap\">\n<table>\n<caption>Ideal heat added to the water (40\u00b0C rise, once per day)<\/caption>\n<thead>\n<tr>\n<th>Tank volume<\/th>\n<th>Assumed temperature rise<\/th>\n<th>Ideal heat added<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>100L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>4.65 kWh<\/strong><\/td>\n<\/tr>\n<tr>\n<td>300L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>13.95 kWh<\/strong><\/td>\n<\/tr>\n<tr>\n<td>500L<\/td>\n<td>40\u00b0C<\/td>\n<td><strong>23.26 kWh<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>These figures exclude tank loss, piping loss, heat-exchanger approach, draw profile and control losses. Their purpose is to show why an energy calculation is required before a tube count.<\/p>\n<h3>3. Buyers choose different solar fractions<\/h3>\n<p>One project may ask solar thermal to cover 30% of the annual hot-water load; another may target 60% or more. The U.S. Department of Energy’s Federal Energy Management Program calculator explicitly sizes solar hot-water systems from solar resource and the percentage of load to be met.<\/p>\n<p>A larger solar fraction normally requires more collector capacity, but oversizing for the best month can create summer stagnation and poor economics. The design must examine monthly demand and solar availability, not only an annual average.<\/p>\n<h3>4. Collector output changes with operating conditions<\/h3>\n<p>Published peak or specified power is tied to test conditions. Actual useful output changes with: solar irradiance, ambient temperature, collector inlet temperature, flow rate, tilt and orientation, shading and soiling, wind, pipe and manifold loss, heat-exchanger performance, and storage temperature and stratification.<\/p>\n<p>A 30-tube collector operating with cold return fluid on a clear day is not equivalent to the same collector trying to maintain a high storage temperature in cold wind.<\/p>\n<h3>5. Complete-system architecture changes the pairing<\/h3>\n<p>The number of tanks, number of coils, collector banks, hydraulic layout, expansion vessel, controller and backup source all influence the final system. JinYi’s published 300L configuration uses two collectors and 36 tubes; SolarMaster and Zantia publish a single 30-tube collector for 300L. At 500L, all three use multiple collector modules, but the total count still varies.<\/p>\n<p>This is why a capacity-to-tube table is useful for market comparison but unsafe as a universal design chart.<\/p>\n<h2 id=\"soletks-hpc\">What SOLETKS Currently Publishes for Its HPC Collectors<\/h2>\n<p>SOLETKS’ HPC technical guide publishes five heat-pipe collector models. The verified table below compares each collector as a <strong>component<\/strong>; it does not assign a tank capacity to any model.<\/p>\n<div class=\"img-card\">\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"SOLETKS HPC evacuated tube heat pipe solar collector component\"><figcaption>SOLETKS HPC range uses \u03a658 \u00d7 1,800mm evacuated tubes across five models \u2014 physical tube count differs from any tank-capacity claim.<\/figcaption><\/div>\n<div class=\"hpc-strip\">\n<div class=\"hpc-model\">\n<div class=\"name\">HPC182<\/div>\n<div class=\"tubes\">12<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">1.20m\u00b2 \u00b7 0.72kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC240<\/div>\n<div class=\"tubes\">16<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">1.60m\u00b2 \u00b7 0.96kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC298<\/div>\n<div class=\"tubes\">20<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">2.00m\u00b2 \u00b7 1.20kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC370<\/div>\n<div class=\"tubes\">25<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">2.50m\u00b2 \u00b7 1.50kW<\/div>\n<\/p><\/div>\n<div class=\"hpc-model\">\n<div class=\"name\">HPC442<\/div>\n<div class=\"tubes\">30<\/div>\n<div class=\"tubes-label\">tubes<\/div>\n<div class=\"area\">3.00m\u00b2 \u00b7 1.80kW<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<div class=\"table-wrap\">\n<table>\n<caption>SOLETKS HPC model, tube count and specified power (at 1,000W\/m\u00b2)<\/caption>\n<thead>\n<tr>\n<th>SOLETKS HPC model<\/th>\n<th>Vacuum tubes<\/th>\n<th>Lighting area<\/th>\n<th>Specified power<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>HPC182<\/td>\n<td>12<\/td>\n<td>1.20m\u00b2<\/td>\n<td>0.72kW<\/td>\n<\/tr>\n<tr>\n<td>HPC240<\/td>\n<td>16<\/td>\n<td>1.60m\u00b2<\/td>\n<td>0.96kW<\/td>\n<\/tr>\n<tr>\n<td>HPC298<\/td>\n<td>20<\/td>\n<td>2.00m\u00b2<\/td>\n<td>1.20kW<\/td>\n<\/tr>\n<tr>\n<td>HPC370<\/td>\n<td>25<\/td>\n<td>2.50m\u00b2<\/td>\n<td>1.50kW<\/td>\n<\/tr>\n<tr>\n<td>HPC442<\/td>\n<td>30<\/td>\n<td>3.00m\u00b2<\/td>\n<td>1.80kW<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>The published range uses \u03a658 \u00d7 1,800mm evacuated tubes, has a 0.6MPa working pressure and a 120\u00b0C maximum operating temperature. The guide also lists a peak efficiency of 0.724 and a total heat-loss coefficient of 2.453W\/(m\u00b2\u00b7K).<\/p>\n<p>Those values allow a qualified designer to compare models and build a collector field. The 1,000W\/m\u00b2 power row is an instantaneous test-condition reference, not a daily-energy promise. Daily and annual yield still require local irradiation, temperature and loss inputs.<\/p>\n<div class=\"note-box\">\n<div class=\"icon\">\u2715<\/div>\n<div class=\"text\">\n<p><strong>Most importantly:<\/strong> SOLETKS does not currently publish a verified table saying 100L = a specific HPC model or quantity, 300L = a specific HPC model or quantity, or 500L = a specific HPC model or quantity. Until such a table is issued and technically approved, buyers should request a project calculation rather than treat a competitor’s 10\/30\/50 pattern as a SOLETKS recommendation.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<h2 id=\"method\">A Two-Stage Method for Choosing the Collector<\/h2>\n<div class=\"stage-grid\">\n<div class=\"stage-card stage1\">\n<div class=\"stage-num\">1<\/div>\n<h3>Define the Thermal Requirement<\/h3>\n<ol>\n<li>Project location and monthly solar resource<\/li>\n<li>Daily hot-water volume and busiest-hour draw<\/li>\n<li>Cold-water temperature by season<\/li>\n<li>Required storage and delivery temperatures<\/li>\n<li>Target monthly or annual solar fraction<\/li>\n<li>Tank, pipe, recirculation and heat-exchanger losses<\/li>\n<li>Backup-heater type, capacity and operating window<\/li>\n<\/ol><\/div>\n<div class=\"stage-card stage2\">\n<div class=\"stage-num\">2<\/div>\n<h3>Select Tested Collector Area & Quantity<\/h3>\n<ol>\n<li>Use aperture or lighting area consistently<\/li>\n<li>Use the certified efficiency curve at expected conditions<\/li>\n<li>Estimate useful monthly energy, including losses<\/li>\n<li>Check roof area, structural load, wind, snow, spacing<\/li>\n<li>Check pressure drop, branch balance, pump\/exchanger duty<\/li>\n<li>Confirm stagnation, freeze protection, expansion volume<\/li>\n<li>Convert the selected model and quantity into a tube count<\/li>\n<\/ol><\/div>\n<\/p><\/div>\n<p>Calculate the hot-water energy load and the portion intended to come from solar. For commercial work, use a time series or recognized simulation method rather than one daily average.<\/p>\n<div class=\"example-box\">\n<h4>Worked example \u2014 SOLETKS HPC442 concept estimate<\/h4>\n<p>Daily hot water: 5,000L \u00b7 Cold inlet: 15\u00b0C \u00b7 Target preheat: 50\u00b0C \u00b7 Temperature rise: 35\u00b0C<\/p>\n<div class=\"calc-step\">Daily heat demand = 5,000 \u00d7 35 \u00d7 0.001163 = <strong>203.5 kWh\/day<\/strong><\/div>\n<div class=\"calc-step\">Solar target (40% fraction) = 203.5 \u00d7 40% = <strong>81.4 kWh\/day<\/strong><\/div>\n<div class=\"calc-step\">HPC442 at 700W\/m\u00b2 \u00d7 4 useful hours \u2248 <strong>4.6 kWh\/day per collector<\/strong><\/div>\n<div class=\"calc-step\">81.4 \u00f7 4.6 \u2248 <strong>18 HPC442 collectors<\/strong> (before losses & safety factors)<\/div>\n<p style=\"margin-top:12px;font-size:13px;\">This is only an early concept estimate. Final sizing must consider local irradiation, seasonality, tilt, pipe loss, tank size, backup heating, operating temperature, pump strategy and solar-fraction target.<\/p>\n<\/p><\/div>\n<p>This method may produce 30, 36, 50 or 60 tubes for a system in the capacities discussed here. The defensible answer is the one tied to stated inputs and tested performance.<\/p>\n<h2 id=\"certs\">What Certifications Can and Cannot Tell You<\/h2>\n<p>Solar Keymark distinguishes certified solar collectors, factory-made systems and custom-built systems. That distinction matters because a certified collector result does not automatically certify every tank-and-collector combination assembled around it.<\/p>\n<p>Ask the supplier to identify:<\/p>\n<ul>\n<li>the exact certified product or family<\/li>\n<li>whether the certificate applies to the collector, the factory-made system or both<\/li>\n<li>the tested aperture area and performance parameters<\/li>\n<li>whether the quoted tank\/collector combination is included<\/li>\n<li>the current certificate and test-report revision<\/li>\n<\/ul>\n<p>Certification supports comparable performance evidence. It does not eliminate the need for site sizing, hydraulic design or local code review.<\/p>\n<h2 id=\"procurement\">A Procurement Comparison That Is Better Than “Price per Tube”<\/h2>\n<p>Use a normalized quotation table:<\/p>\n<div class=\"table-wrap\">\n<table>\n<thead>\n<tr>\n<th>Procurement field<\/th>\n<th>Why it is required<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Tank model & actual usable volume<\/strong><\/td>\n<td>Nominal litres may not equal drawdown volume<\/td>\n<\/tr>\n<tr>\n<td><strong>Collector model & quantity<\/strong><\/td>\n<td>Links the quote to a verified product<\/td>\n<\/tr>\n<tr>\n<td><strong>Tube diameter, length & count<\/strong><\/td>\n<td>Confirms the physical configuration<\/td>\n<\/tr>\n<tr>\n<td><strong>Gross & aperture\/lighting area<\/strong><\/td>\n<td>Enables like-for-like area comparison<\/td>\n<\/tr>\n<tr>\n<td><strong>Efficiency curve & heat-loss coefficient<\/strong><\/td>\n<td>Supports output calculations beyond peak efficiency<\/td>\n<\/tr>\n<tr>\n<td><strong>Specified output with test conditions<\/strong><\/td>\n<td>Prevents an unqualified power claim<\/td>\n<\/tr>\n<tr>\n<td><strong>System or collector certificate<\/strong><\/td>\n<td>Shows what was independently evaluated<\/td>\n<\/tr>\n<tr>\n<td><strong>Heat-exchanger type & area<\/strong><\/td>\n<td>Confirms that collector heat can enter the tank<\/td>\n<\/tr>\n<tr>\n<td><strong>Pump, design flow & pressure drop<\/strong><\/td>\n<td>Supports hydraulic performance<\/td>\n<\/tr>\n<tr>\n<td><strong>Expansion vessel & safety valves<\/strong><\/td>\n<td>Supports closed-loop safety<\/td>\n<\/tr>\n<tr>\n<td><strong>Backup heater & recovery time<\/strong><\/td>\n<td>Shows how demand is met when solar is insufficient<\/td>\n<\/tr>\n<tr>\n<td><strong>Freeze & stagnation strategy<\/strong><\/td>\n<td>Protects the system at both temperature extremes<\/td>\n<\/tr>\n<tr>\n<td><strong>Monthly energy estimate & assumptions<\/strong><\/td>\n<td>Makes solar-fraction claims auditable<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<p>Price should be compared only after these fields are aligned. A system with fewer tubes may have a larger effective area or stronger tested output; a system with more tubes may be compensating for a smaller collector module or a more demanding design target.<\/p>\n<h2 id=\"mistakes\">Common Mistakes When Interpreting Tube-Count Tables<\/h2>\n<div class=\"mistake-grid\">\n<div class=\"mistake-card\">\n<div class=\"num\">1<\/div>\n<h4>Treating litres per tube as a physical constant<\/h4>\n<p>“Ten litres per tube” is a product-family pattern, not a law of solar thermal design. It does not replace an energy balance.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">2<\/div>\n<h4>Comparing heat-pipe and direct-flow systems by count<\/h4>\n<p>Collector construction and fluid path differ. Keep the comparison within the same technology class and use tested area and output.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">3<\/div>\n<h4>Ignoring the number of collector modules<\/h4>\n<p>A 500L row may say “50 tubes,” but the physical system can be two 25-tube collectors, affecting piping and layout.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">4<\/div>\n<h4>Using peak power as daily energy<\/h4>\n<p>Kilowatts describe power at a moment. Kilowatt-hours describe energy over time. Daily yield requires irradiance and condition data.<\/p>\n<\/div>\n<div class=\"mistake-card\">\n<div class=\"num\">5<\/div>\n<h4>Assuming a competitor configuration is a SOLETKS configuration<\/h4>\n<p>The comparison table documents how other manufacturers package systems \u2014 it does not fill the missing SOLETKS capacity-to-HPC mapping.<\/p>\n<\/div><\/div>\n<h2 id=\"faq\">Frequently Asked Questions<\/h2>\n<details class=\"faq-item\" open>\n<summary>How many heat-pipe tubes are needed for a 100L solar water heater?<\/summary>\n<div class=\"faq-body\">One published SolarMaster system uses a single 10-tube collector for 100L. That is a manufacturer-specific configuration, not a universal requirement. Confirm tube size, aperture area, tested output, climate and target solar fraction.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>How many tubes are needed for a 300L tank?<\/summary>\n<div class=\"faq-body\">The reviewed manufacturer tables publish 30 tubes from SolarMaster and Zantia, and 36 tubes across two collectors from JinYi. A project-specific calculation must decide which performance level is appropriate.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>How many tubes are needed for a 500L tank?<\/summary>\n<div class=\"faq-body\">The reviewed tables publish either 50 tubes across two 25-tube collectors or 60 tubes across two 30-tube collectors. The correct choice depends on collector performance, solar resource, temperature lift, system loss and solar-fraction target.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>Does SOLETKS recommend 10, 30 and 50 tubes for 100L, 300L and 500L?<\/summary>\n<div class=\"faq-body\">No verified SOLETKS capacity-to-HPC table is currently published. SOLETKS publishes HPC collectors with 12, 16, 20, 25 and 30 tubes and provides area and output data by model. A system proposal should select those models from the project load.<\/div>\n<\/details>\n<details class=\"faq-item\">\n<summary>Is a higher tube count always better?<\/summary>\n<div class=\"faq-body\">No. More tubes can increase collector area within the same product family, but cross-brand comparison requires tested aperture area, efficiency, heat loss and output. Excess collector capacity can also increase stagnation risk.<\/div>\n<\/details>\n<p> <\/p>\n<div class=\"cta-band\">\n<h2>Request a Load-Based Heat-Pipe System Proposal<\/h2>\n<p>Send the project location, daily hot-water demand, inlet and target temperatures, load schedule, target solar fraction, roof information and backup source. SOLETKS can then propose the HPC model quantity, storage, heat exchanger, hydraulic components and controls as one engineered system.<\/p>\n<p> <a class=\"btn btn-primary\" href=\"https:\/\/service.soletksolar.com\/contact\/\">Contact SOLETKS Engineering<\/a>\n <\/div>\n<h2>Continue the Heat-Pipe Selection Topic Cluster<\/h2>\n<div class=\"related-grid\">\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Vacuum-tube-solar-collector.jpg\" alt=\"SOLETKS HPC heat pipe solar collector guide\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Component Guide<\/span><\/p>\n<h4>HPC Heat Pipe Solar Collector \u2014 Full Verified Specifications<\/h4>\n<\/p><\/div>\n<p> <\/a><br \/>\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/products\/solar-water-heater\/heat-pipe-solar-water-heater\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Harz-Church-Hot-Water-Project-Germany.png\" alt=\"SOLETKS heat pipe solar water heater integrated product range\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Product Range<\/span><\/p>\n<h4>SOLETKS Heat Pipe Solar Water Heater \u2014 Integrated Product Line<\/h4>\n<\/p><\/div>\n<p> <\/a><br \/>\n <a class=\"related-card\" href=\"https:\/\/service.soletksolar.com\/compact-heat-pipe-solar-water-heater\/\"><br \/>\n <img decoding=\"async\" src=\"https:\/\/service.soletksolar.com\/wp-content\/uploads\/2025\/11\/Florida-Resort-Villa-Hot-Water-Project-USA.png\" alt=\"Compact heat pipe solar water heater cold-climate selection guide\"><\/p>\n<div class=\"rc-body\">\n <span class=\"rc-tag\">Cold-Climate Guide<\/span><\/p>\n<h4>Compact Heat Pipe Solar Water Heater: Cold-Climate Selection<\/h4>\n<\/p><\/div>\n<p> <\/a>\n <\/div>\n<p style=\"font-size:14px;\">For verified component data, see the <a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">SOLETKS HPC Heat Pipe Solar Collector Guide<\/a>. For the current integrated-product range, see the <a href=\"https:\/\/service.soletksolar.com\/products\/solar-water-heater\/heat-pipe-solar-water-heater\/\">SOLETKS Heat Pipe Solar Water Heater<\/a>. The existing <a href=\"https:\/\/service.soletksolar.com\/compact-heat-pipe-solar-water-heater\/\">Compact Heat Pipe Solar Water Heater guide<\/a> covers cold-climate selection and remains the destination for that broader intent.<\/p>\n<p> <\/p>\n<h2>Sources<\/h2>\n<ol class=\"sources-list\">\n<li><a href=\"https:\/\/www.solarmastertech.com\/?page_id=20647&post_type=products\" target=\"_blank\" rel=\"noopener\">SolarMaster \u2014 Split Pressurized Solar Water Heater product range<\/a><\/li>\n<li><a href=\"https:\/\/www.jinyi-solar.com\/heat-pipe-solar-water-heating-system.html\" target=\"_blank\" rel=\"noopener\">JinYi \u2014 Heat Pipe Solar Water Heating System<\/a><\/li>\n<li><a href=\"https:\/\/zantia.com\/zantia\/public\/index.php\/climatizacao\/energias-renovaveis\/energia-solar-termica\/kits-solares\/heat-pipe-forced-circulation-kits\" target=\"_blank\" rel=\"noopener\">Zantia \u2014 Heat Pipe Forced-Circulation Kits<\/a><\/li>\n<li><a href=\"https:\/\/www.energy.gov\/cmei\/femp\/articles\/solar-hot-water-system-calculator\" target=\"_blank\" rel=\"noopener\">U.S. Department of Energy FEMP \u2014 Solar Hot Water System Calculator<\/a><\/li>\n<li><a href=\"https:\/\/solarkeymark.eu\/stakeholders\/manufacturers\/\" target=\"_blank\" rel=\"noopener\">Solar Keymark \u2014 Information for Manufacturers<\/a><\/li>\n<li><a href=\"https:\/\/service.soletksolar.com\/hpc-heat-pipe-solar-collector\/\">SOLETKS \u2014 HPC Heat Pipe Solar Collector Guide<\/a><\/li>\n<li><a href=\"https:\/\/service.soletksolar.com\/solar-water-heater-system-for-homes-hotels-and-commercial-projects\/\">SOLETKS \u2014 Solar Water Heater System Design Guide<\/a><\/li>\n<\/ol><\/div>\n<p><\/main><\/p>\n<p><\/body><br \/>\n<\/html><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Compare published heat-pipe tube counts for 100L, 300L and 500L solar tanks, then size by collector area, output, climate and solar fraction.<\/p>","protected":false},"author":1,"featured_media":352,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[16,9],"class_list":["post-1791","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-evacuated-tube-collector","tag-solar-thermal"],"_links":{"self":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts\/1791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/comments?post=1791"}],"version-history":[{"count":0,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/posts\/1791\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/media\/352"}],"wp:attachment":[{"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/media?parent=1791"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/categories?post=1791"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/service.soletksolar.com\/cs\/wp-json\/wp\/v2\/tags?post=1791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}