{"id":136794,"date":"2025-06-16T10:43:22","date_gmt":"2025-06-16T08:43:22","guid":{"rendered":"https:\/\/www.velasolaris.com\/?post_type=handbuch&#038;p=136794"},"modified":"2025-10-20T16:28:30","modified_gmt":"2025-10-20T14:28:30","slug":"iso-9806-konversion","status":"publish","type":"handbuch","link":"https:\/\/www.velasolaris.com\/en\/handbuch\/polysun-designer\/producers\/solar-thermal-collectors\/iso-9806-konversion\/","title":{"rendered":"Conversion models of the collector parameters between EN 12975 and ISO 9806"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">As the physical models and parameters differ between EN 12975 and ISO 9806, the following describes how catalogue entries for European, ASHRAE, Chinese and PVT collectors are migrated.<br>An overview table explaining the ISO 9806 catalogue can be found <a href=\"https:\/\/www.velasolaris.com\/en\/handbuch\/polysun-designer\/solar-thermal-and-conventional-heating-systems\/solar-thermal-collectors\/collector-model-according-to-iso-9806\/\">here<\/a>.<\/p>\n\n\n\n<section id=\"res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33\" class=\"res-collapse py-5\" style=\"background-color: transparent;\">\n    <div class=\"inner-container container-fluid\" >\n\n        <div id=\"accordion_sAC2p5oN9s\" class=\"collapse-all\">\n\t\t\t\t\t\t\t                    <div class=\"card\">\n                        <div class=\"collapsed\" data-toggle=\"collapse\" data-target=\"#collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-1\" aria-expanded=\"true\" aria-controls=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-1\">\n                            <div class=\"card-header d-flex justify-content-between\" id=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-1\">\n\t\t\t\t\t\t\t\t<h2 class=\"title style-auto\">European collectors (EN 12975) in ISO 9806<\/h2>                                <div class=\"collapse-icon\" id=\"arrow-collapse\"> <i class=\"fal fa-angle-down rotate-icon\"><\/i> <\/div>\n                            <\/div>\n                        <\/div>\n\n                        <div id=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-1\" class=\"collapse\" aria-labelledby=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-1\" data-parent=\"#accordion_sAC2p5oN9s\">\n                            <div class=\"card-body\">\n\t\t\t\t\t\t\t\t<p>The following table lists the parameters of the European collectors in accordance with EN 12975.<\/p>\n<p><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<tbody>\n<tr>\n<td><strong>Parameters<\/strong><\/td>\n<td><strong>Unit<\/strong><\/td>\n<td><strong>Symbol<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Eta0 (laminar);<br \/>\nbu<\/td>\n<td>[-] ;<\/p>\n<p>\\(\\frac{s}{m}\\)<\/td>\n<td>\\(\\eta_{0,l}\\);<br \/>\n\\(b_{u}\\)<\/td>\n<\/tr>\n<tr>\n<td>Eta0 (turbulent)<\/td>\n<td>[-]<\/td>\n<td>\\(\\eta_{0,t}\\)<\/td>\n<\/tr>\n<tr>\n<td>A1 (without wind); b1<\/td>\n<td>\\(\\frac{W}{m^{2}K}\\)<\/td>\n<td>\\(A_{1,nowind}\\) ; \\(b_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>A1 (with wind);<br \/>\nb2<\/td>\n<td>\\(\\frac{W}{m^{2}K}\\);<\/p>\n<p>\\(\\frac{Ws}{m^{3}K}\\)<\/td>\n<td>\\(A_{1,wind}\\) ;<br \/>\n\\(b_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>A2;<br \/>\nEpsilon\/Alpha<\/td>\n<td>\\(\\frac{W}{m^{2}K^{2}}\\);<\/p>\n<p>[-]<\/td>\n<td>\\(A_{2}\\) ; \\(\\frac{\\epsilon}{\\alpha}\\)<\/td>\n<\/tr>\n<tr>\n<td>A3<\/td>\n<td>\\(\\frac{W}{m^{2}K^{2}}\\)<\/td>\n<td>\\(A_{3}\\)<\/td>\n<\/tr>\n<tr>\n<td>bu (cold collector)<\/td>\n<td>\\(\\frac{s}{m}\\)<\/td>\n<td>\\(b_{u,cold}\\)<\/td>\n<\/tr>\n<tr>\n<td>b1 (cold collector)<\/td>\n<td>\\(\\frac{W}{m^{2}K}\\)<\/td>\n<td>\\(b_{1,cold}\\)<\/td>\n<\/tr>\n<tr>\n<td>b2 (cold collector)<\/td>\n<td>\\(\\frac{Ws}{m^{3}K}\\)<\/td>\n<td>\\(b_{2,cold}\\)<\/td>\n<\/tr>\n<tr>\n<td>Dynamic heat capacity<\/td>\n<td>\\(\\frac{J}{K}\\)<\/td>\n<td>\\(c_{dyn}\\)<\/td>\n<\/tr>\n<tr>\n<td>Diffuse irradiation fraction<\/td>\n<td>[-]<\/td>\n<td>\\(f_{diff}\\)<\/td>\n<\/tr>\n<tr>\n<td>Volume<\/td>\n<td>l<\/td>\n<td>\\(V_{EN}\\)<\/td>\n<\/tr>\n<tr>\n<td>Internal pipe diameter<\/td>\n<td>mm<\/td>\n<td>\\(D_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Single pipe length<\/td>\n<td>m<\/td>\n<td>\\(l_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Parallel piping<\/td>\n<td>[-]<\/td>\n<td>\\(p_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pipe roughness<\/td>\n<td>[-]<\/td>\n<td>\\(\\xi_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Linear form factor<\/td>\n<td>[-]<\/td>\n<td>\\(z_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>Friction factor<\/td>\n<td>[-]<\/td>\n<td>\\(z_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>Mixture concentration during test<\/td>\n<td>[-]<\/td>\n<td>\\(x_{mix}\\)<\/td>\n<\/tr>\n<tr>\n<td>Test flow rate<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{test}\\)<\/td>\n<\/tr>\n<tr>\n<td>Maximum pressure<\/td>\n<td>bar<\/td>\n<td>\\(p_{max}\\)<\/td>\n<\/tr>\n<tr>\n<td>Maximum temperature<\/td>\n<td>\u00b0C<\/td>\n<td>\\(T_{max}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pipes per Panel<\/td>\n<td>[-]<\/td>\n<td>\\(n_{pipes}\\)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n<p><!-- \/wp:table --><\/p>\n<p>Depending on the chosen norm in the catalog column &#8220;Testing standard Solar Keymark&#8221; of the original EN 12975 catalog entry, a conversion factor needs to be multiplied to the old EN 12975 parameters:<\/p>\n<ul>\n<li>If the Solar Keymark standard column is empty or is set to &#8220;EN 12975&#8221; \\(f_{Area}=\\frac{A_{aperture}}{A_{gross}} \\)<\/li>\n<li>If the Solar Keymark standard column is set to &#8220;EN ISO 9806:2013&#8221; or &#8220;EN ISO 9806:2017&#8221;<\/li>\n<li>\\(f_{Area}=1 \\)<\/li>\n<\/ul>\n<p>The following calculations are used to convert the old collector data for ISO 9806:<\/p>\n<ol>\n<li><strong><strong>Efficiency \\(\\eta_{0,b}\\)<br \/>\n<\/strong><\/strong>a. For flat-plate and vacuum tube collectors with \\(K_{d,0}\\) as diffuser IAM factor = 0,95 \\(\\eta_{0,b} = \\frac{\\eta_{0,t}\\cdot f_{Area}}{0.85+0.15K_{d,0}}\\)<br \/>\nb. For unglazed collectors \\(\\eta_{0,b} = {\\eta_{0,t} \\cdot} f_{Area} \\cdot {(1- 3b_{u})}\\)<br \/>\nc. For concentrating collectors with the Reynolds number \\(Re_{0}\\) = 5000 \\(eta_{0,b} = 2\\cdot f_{Area}\\cdot( \\eta_{0,l} &#8211; \\eta_{0,t}) + 3(\\eta_{0,t}-\\eta_{0,l})(1- \\frac{1}{1+\\frac{Re_{0}}{2000}})\\)<\/li>\n<li><strong><strong>Heat loss coefficient \\(a_{1}\\)<br \/>\n<\/strong><\/strong>a. For flat-plate, vacuum tube and concentrating collectors: \\(A_{1,wind} \\cdot f_{Area} = a_{1}\\)b. For unglazed collectors: \\(b_{1}\\cdot f_{Area} = a_{1 }\\)<\/li>\n<li><strong><strong>Temperature dependence of the heat loss coefficient \\(a_{2}\\)<br \/>\n<\/strong><\/strong>a. For flat-plate, vacuum tube and concentrating collectors: \\(A_{2} \\cdot f_{Area} = a_{2 }\\)<br \/>\nb. For unglazed collectors: 0 = \\(a_{2}\\)<\/li>\n<li><strong><strong><strong>Wind speed dependence of the heat loss coefficient \\(a_{3}\\)<br \/>\n<\/strong><\/strong><\/strong>a. For flat-plate, vacuum tube and concentrating collectors: 0 = \\(a_{3}\\)<br \/>\nb. For unglazed collectors: \\(b_{2} \\cdot f_{Area} = a_{3 }\\)<\/li>\n<li><strong><strong><strong>Sky temperature dependence of the heat loss coefficient \\(a_{4}\\)<br \/>\n<\/strong><\/strong><\/strong>a. For flat-plate, vacuum tube and concentrating collectors: 0 = \\(a_{4}\\)<br \/>\nb. For unglazed collectors: \\(\\frac{\\epsilon}{\\alpha} \\cdot f_{Area} = a_{4}\\)<\/li>\n<li><strong>Effective thermal capacity \\(a_{5}\\)<br \/>\n<\/strong>a. \\(\\frac{c_{dyn}}{A_{gross}} = a_{5}\\)<\/li>\n<li><strong><strong><strong>Wind speed dependence of the zero loss efficiency \\(a_{6}\\)<br \/>\n<\/strong><\/strong><\/strong>a. For flat-plate, vacuum tube and concentrating collectors: 0 = \\(a_{6}\\)<br \/>\nb. For unglazed collectors: \\(\\eta_{0,t} \\cdot b_{u}\\cdot f_{Area}^{2} = a_{6}\\)<\/li>\n<li><strong><strong>Effects of wind speed on radiation loss<br \/>\n<\/strong><\/strong>a. 0 = \\(a_{7}\\)<\/li>\n<li><strong><strong>Radiation losses<br \/>\n<\/strong><\/strong>a. 0 = \\(a_{8}\\)<\/li>\n<li><strong>Diffuse IAM factor \\(K_{d}\\)<br \/>\n<\/strong>a. For flat-plate, vacuum tube and concentrating collectors: \\(K_{d} = 0.95\\)<br \/>\nb. For unglazed collectors: \\(K_{d} = f_{diff}\\)if \\(f_{diff}\\) is not set: \\(K_{d} = 0.2\\)<\/li>\n<li><strong>Volume<br \/>\n<\/strong>\\(V = max(V_{EN}, \\frac{D_{pipe}^2}{4} \\cdot \\pi \\cdot l_{pipe} \\cdot p_{pipe})\\)<\/li>\n<\/ol>\n                            <\/div>\n                        <\/div>\n\n                    <\/div>\n\t\t\t\t\n\t\t\t\t                    <div class=\"card\">\n                        <div class=\"collapsed\" data-toggle=\"collapse\" data-target=\"#collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-2\" aria-expanded=\"true\" aria-controls=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-2\">\n                            <div class=\"card-header d-flex justify-content-between\" id=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-2\">\n\t\t\t\t\t\t\t\t<h2 class=\"title style-auto\">ASHRAE collectors in ISO 9806<\/h2>                                <div class=\"collapse-icon\" id=\"arrow-collapse\"> <i class=\"fal fa-angle-down rotate-icon\"><\/i> <\/div>\n                            <\/div>\n                        <\/div>\n\n                        <div id=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-2\" class=\"collapse\" aria-labelledby=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-2\" data-parent=\"#accordion_sAC2p5oN9s\">\n                            <div class=\"card-body\">\n\t\t\t\t\t\t\t\t<p>The following table lists the parameters of the ASHRAE collectors.<\/p>\n<p><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\"><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<tbody>\n<tr>\n<td><strong>Parameters<\/strong><\/td>\n<td><strong>Unit<\/strong><\/td>\n<td><strong>Symbol<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Dry weight<\/td>\n<td>kg<\/td>\n<td>\\(m_{dry}\\)<\/td>\n<\/tr>\n<tr>\n<td>Eta0<\/td>\n<td>[-]<\/td>\n<td>\\(\\eta_{0}\\)<\/td>\n<\/tr>\n<tr>\n<td>A1<\/td>\n<td>\\(\\frac{W}{m^{2}K}\\)<\/td>\n<td>\\(A_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>A2<\/td>\n<td>\\(\\frac{W}{m^{2}K^{2}}\\)<\/td>\n<td>\\(A_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>A3<\/td>\n<td>\\(\\frac{W}{m^{2}K^{2}}\\)<\/td>\n<td>\\(A_{3}\\)<\/td>\n<\/tr>\n<tr>\n<td>Dynamic heat capacity<\/td>\n<td>\\(\\frac{J}{K}\\)<\/td>\n<td>\\(c_{dyn}\\)<\/td>\n<\/tr>\n<tr>\n<td>Diffuse irradiation fraction<\/td>\n<td>[-]<\/td>\n<td>\\(f_{diff}\\)<\/td>\n<\/tr>\n<tr>\n<td>Volume<\/td>\n<td>l<\/td>\n<td>\\(V\\)<\/td>\n<\/tr>\n<tr>\n<td>Flow rate 1<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pressure loss 1<\/td>\n<td>Pa<\/td>\n<td>\\(\\delta p_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>Flow rate 2<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pressure loss 2<\/td>\n<td>Pa<\/td>\n<td>\\(\\delta p_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>Flow rate 3<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{3}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pressure loss 3<\/td>\n<td>Pa<\/td>\n<td>\\(\\delta p_{3}\\)<\/td>\n<\/tr>\n<tr>\n<td>Test flow rate<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{test}\\)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n<p><!-- \/wp:table --><\/figure>\n<p><!-- \/wp:table --><\/p>\n<p>The following calculations are used to convert the old collector data for ISO 9806:<\/p>\n<ol>\n<li><strong><strong>Efficiency \\(\\eta_{0} = \\eta_{0,b}\\)<\/strong><\/strong><\/li>\n<li><strong><strong><strong>Heat loss coefficient \\(a_{1}\\)<\/strong><\/strong><\/strong>\\(|A_{1}| = a_{1}\\)<\/li>\n<li><strong><strong>Temperature dependence of the heat loss coefficient \\(a_{2}\\)<br \/>\n<\/strong><\/strong>\\(|A_{2}| = a_{2}\\)<\/li>\n<li><strong>Wind speed dependence of the heat loss coefficient \\(a_{3}\\)<br \/>\n<\/strong>\\(a_{3} = \\frac {a_{1}\\cdot f_{c}-a_{1}}{3}\\) where the coefficient is \\(f_{c}\\):<br \/>\na. For flat-plate collectors:<br \/>\n\\(f_{c} = 1.1 \\frac{J}{m^3 K}\\)<br \/>\nb. For vacuum tube collectors:\\(f_{c} = 1.05 \\frac{J}{m^3 K}\\)<\/p>\n<p>c. For unglazed and concentrating collectors:<\/p>\n<p>\\(f_{c} = 1.2 \\frac{J}{m^3 K}\\)<\/li>\n<li><strong><strong>Sky temperature dependence of the heat loss coefficient \\(a_{4}\\)<\/strong><\/strong>\\(0 = a_{4}\\)<\/li>\n<li><strong>Effective thermal capacity \\(a_{5}\\)<br \/>\n<\/strong>a. \\(\\frac{c_{dyn}}{A_{gross}} = a_{5}\\)<br \/>\nb. If the dynamic heat capacity was not specified: \\(\\frac{10&#8217;000}{A_ {gross}}\\)<\/li>\n<li><strong><strong>Wind speed dependence of the zero loss efficiency \\(a_{6}\\)<\/strong><\/strong>\\(0 = a_{6}\\)<\/li>\n<li><strong><strong>wind speed effect on radiation loss<\/strong><\/strong>0 = \\(a_{7}\\)<\/li>\n<li><strong><strong>Radiation loss<\/strong><\/strong>0 = \\(a_{8}\\)<\/li>\n<li><strong><strong><strong>Diffuse IAM factor \\(K_{d}\\)<br \/>\n<\/strong><\/strong><\/strong>a. For flat-plate and vacuum tube collectors with: \\(K_{d} = 0.95\\)<br \/>\nb. For concentrating collectors: \\(K_{d} = f_{diff}\\)if \\(f_{diff}\\) is not set: \\(K_{d} = 0.2\\)<\/li>\n<li><strong><strong><strong>Volume<\/strong><\/strong><\/strong>\\(V = max(V_{EN}, \\frac{D_{pipe}^2}{4} \\cdot \\pi \\cdot l_{pipe} \\cdot p_{pipe})\\)<\/li>\n<li><strong>Maximum temperature<\/strong>\\(T_{max} =0\\)<\/li>\n<li><strong>North-South axis\u00a0<\/strong>\\(N_{axis} = 0\\)<\/li>\n<\/ol>\n                            <\/div>\n                        <\/div>\n\n                    <\/div>\n\t\t\t\t\n\t\t\t\t                    <div class=\"card\">\n                        <div class=\"collapsed\" data-toggle=\"collapse\" data-target=\"#collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-3\" aria-expanded=\"true\" aria-controls=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-3\">\n                            <div class=\"card-header d-flex justify-content-between\" id=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-3\">\n\t\t\t\t\t\t\t\t<h2 class=\"title style-auto\">Chinese collectors in ISO 9806<\/h2>                                <div class=\"collapse-icon\" id=\"arrow-collapse\"> <i class=\"fal fa-angle-down rotate-icon\"><\/i> <\/div>\n                            <\/div>\n                        <\/div>\n\n                        <div id=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-3\" class=\"collapse\" aria-labelledby=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-3\" data-parent=\"#accordion_sAC2p5oN9s\">\n                            <div class=\"card-body\">\n\t\t\t\t\t\t\t\t<p>The following table lists the parameters of the Chinese collectors.<\/p>\n<p><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\"><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\"><!-- wp:table --><\/p>\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<tbody>\n<tr>\n<td><strong>Parameters<\/strong><\/td>\n<td><strong>Unit<\/strong><\/td>\n<td><strong>Symbol<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Eta0<\/td>\n<td>[-]<\/td>\n<td>\\(\\eta_{0}\\)<\/td>\n<\/tr>\n<tr>\n<td>A1<\/td>\n<td>\\(\\frac{W}{m^{2}K}\\)<\/td>\n<td>\\(A_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>A2<\/td>\n<td>\\(\\frac{W}{m^{2}K^{2}}\\)<\/td>\n<td>\\(A_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>Dynamic heat capacity<\/td>\n<td>\\(\\frac{J}{K}\\)<\/td>\n<td>\\(c_{dyn}\\)<\/td>\n<\/tr>\n<tr>\n<td>Volume<\/td>\n<td>l<\/td>\n<td>\\(V_{EN}\\)<\/td>\n<\/tr>\n<tr>\n<td>Internal pipe diameter<\/td>\n<td>mm<\/td>\n<td>\\(D_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Single pipe length<\/td>\n<td>m<\/td>\n<td>\\(l_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Parallel piping<\/td>\n<td>[-]<\/td>\n<td>\\(p_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Pipe roughness<\/td>\n<td>[-]<\/td>\n<td>\\(\\xi_{pipe}\\)<\/td>\n<\/tr>\n<tr>\n<td>Linear form factor<\/td>\n<td>[-]<\/td>\n<td>\\(z_{1}\\)<\/td>\n<\/tr>\n<tr>\n<td>Friction factor<\/td>\n<td>[-]<\/td>\n<td>\\(z_{2}\\)<\/td>\n<\/tr>\n<tr>\n<td>Mixture concentration during test<\/td>\n<td>[-]<\/td>\n<td>\\(x_{mix}\\)<\/td>\n<\/tr>\n<tr>\n<td>Test flow rate<\/td>\n<td>\\(\\frac{l}{h}\\)<\/td>\n<td>\\(\\dot{V}_{test}\\)<\/td>\n<\/tr>\n<tr>\n<td>Maximum pressure<\/td>\n<td>bar<\/td>\n<td>\\(p_{max}\\)<\/td>\n<\/tr>\n<tr>\n<td>Maximum temperature<\/td>\n<td>\u00b0C<\/td>\n<td>\\(T_{max}\\)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n<p><!-- \/wp:table --><\/figure>\n<p><!-- \/wp:table --><\/figure>\n<p><!-- \/wp:table --><\/p>\n<p>The factor \\(f_{Area}=\\frac{A_{aperture}}{A_{gross}} \\) is multiplied to all the old EN 12975 parameters and the following assumption were carried out to obtain the final ISO 9806 collector parameters:<\/p>\n<ol>\n<li><strong><strong>Efficiency \\(\\eta_{0} \\cdot f_{Area} = \\eta_{0,b}\\)<\/strong><\/strong><\/li>\n<li><strong><strong><strong>Heat loss coefficient \\(a_{1} \\)<\/strong><\/strong><\/strong>\\(|A_{1}| \\cdot f_{Area} = a_{1}\\)<\/li>\n<li><strong><strong><strong>Temperature dependence of the heat loss coefficient \\(a_{2}\\)<\/strong><\/strong><\/strong>\\(|A_{2}| \\cdot f_{Area} = a_{2}\\)<\/li>\n<li><strong><strong>Wind speed dependence of the heat loss coefficient \\(a_{3}\\)<\/strong><\/strong>\\(a_{3} = \\frac {a_{1}\\cdot f_{c}-a_{1}}{3} \\cdot f_{Area}\\) where the coefficient is \\(f_{c}\\):<br \/>\na. For flat-plate collectors:\\(f_{c} = 1.1 \\frac{J}{m^3 K}\\)<\/p>\n<p>b. For vacuum tube collectors:<\/p>\n<p>\\(f_{c} = 1.05 \\frac{J}{m^3 K}\\)<\/p>\n<p>c. For unglazed and concentrating collectors:<\/p>\n<p>\\(f_{c} = 1.2 \\frac{J}{m^3 K}\\)<\/li>\n<li><strong><strong>Sky temperature dependence of the heat loss coefficient \\(a_{4}\\)<\/strong><\/strong>\\(0 = a_{4}\\)<\/li>\n<li><strong>Effective thermal capacity \\(a_{5}\\)<br \/>\n<\/strong><br \/>\n\\(\\frac{c_{dyn}}{A_{gross}} = a_{5}\\)<\/li>\n<li><strong><strong>Wind speed dependence of the zero loss efficiency \\(a_{6}\\)<\/strong><\/strong>\\(0 = a_{6}\\)<\/li>\n<li><strong>Wind speed effect on radiation loss<br \/>\n<\/strong>0 = \\(a_{7}\\)<\/li>\n<li><strong>Radiation loss<br \/>\n<\/strong>0 = \\(a_{8}\\)<\/li>\n<li><strong><strong>Diffuse IAM factor \\(K_{d}\\)<br \/>\n<\/strong><\/strong>a. For flat-plate and vacuum tube collectors with: \\(K_{d} = 0.95\\)b. For concentrating collectors: \\(K_{d} = f_{diff}\\)if \\(f_{diff}\\) is not set: \\(K_{d} = 0.2\\)<\/li>\n<li><strong><strong>Volume<br \/>\n<\/strong><\/strong>\\(V = max(V_{EN}, \\frac{D_{pipe}^2}{4} \\cdot \\pi \\cdot l_{pipe} \\cdot p_{pipe})\\)<\/li>\n<li><strong>Maximum temperature<br \/>\n<\/strong>\\(T_{max} =0\\)<\/li>\n<li><strong>North-south axis<br \/>\n<\/strong>\\(N_{axis} = 0\\)<\/li>\n<\/ol>\n                            <\/div>\n                        <\/div>\n\n                    <\/div>\n\t\t\t\t\n\t\t\t\t                    <div class=\"card\">\n                        <div class=\"collapsed\" data-toggle=\"collapse\" data-target=\"#collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-4\" aria-expanded=\"true\" aria-controls=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-4\">\n                            <div class=\"card-header d-flex justify-content-between\" id=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-4\">\n\t\t\t\t\t\t\t\t<h2 class=\"title style-auto\">Conversion of IAM data into k-values<\/h2>                                <div class=\"collapse-icon\" id=\"arrow-collapse\"> <i class=\"fal fa-angle-down rotate-icon\"><\/i> <\/div>\n                            <\/div>\n                        <\/div>\n\n                        <div id=\"collapse-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-4\" class=\"collapse\" aria-labelledby=\"heading-res-collapse-block_ceafe5aaf021fb7ffcfa853ad4d8bd33-4\" data-parent=\"#accordion_sAC2p5oN9s\">\n                            <div class=\"card-body\">\n\t\t\t\t\t\t\t\t<p>This section describes the conversion of IAM types and data entries from the old catalogues to the k-values used in ISO 9806. The conversion rules are the same for all types of collectors and PVT collectors (Collector, CollectorAshrae, CollectorChina, PVTCollector, PVTCollectorAshrae).<\/p>\n<p>The conversion model depends on the IAM model previously selected in the catalogue entry.<\/p>\n<ul>\n<li>IAM model \u00abAmbrosetti\u00bb and \u00abASHRAE\u00bb \\(k_{\\gamma, i} = 1 &#8211; (tan(\\frac{|\\theta_{i}|}{2}))^{a_{\\gamma}}\\) \\(a_{\\gamma} = \\frac{ln(1- iam_{value, \\gamma})}{ln (tan(\\frac {iam_{elevation, \\gamma}}{2}))}\\)<\/li>\n<li>IAM model \u00abTable\u00bb<br \/>\nIn this case, the same angle factors are assigned to the k values.\\(k_{l,i} = iam_{value, 0, i}\\)<br \/>\n\\(k_{t,i} = iam_{value, 90, i}\\)<\/p>\n<p data-renderer-start-pos=\"891\">In the new catalog the k values are set in 10\u00b0 intervals, starting at 10\u00b0 until 90\u00b0. During the catalog conversion any intermediate values (e.g, 15\u00b0) will be ignored.<\/p>\n<p data-renderer-start-pos=\"1063\">If IAM values for some incidence angle between 10\u00b0 and 90\u00b0 with 10 \u00b0 interval were missing, these are calculated through a linear interpolation:<\/p>\n<p>\\(k_{missing}=k_{previous}+(k_{next}-k_{previous})\\cdot \\frac{\\theta_{missing}-\\theta_{previous}}{\\theta_{next}-\\theta_{previous}} \\)<\/p>\n<p>The starting values for the interpolation are 1 for the angle 0\u00b0 and 0 for the angle of 90\u00b0. If the value at 10\u00b0 is higher then 1, then the k value at 0 \u00b0 is set to the same value.<\/li>\n<\/ul>\n                            <\/div>\n                        <\/div>\n\n                    <\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t        <\/div>\n\n\n\n    <\/div>\n<\/section>","protected":false},"author":135679,"featured_media":0,"parent":117670,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","class_list":["post-136794","handbuch","type-handbuch","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v28.0 (Yoast SEO v28.0) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Conversion models of the collector parameters between EN 12975 and ISO 9806 - POLYSUN<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.velasolaris.com\/en\/handbuch\/polysun-designer\/producers\/solar-thermal-collectors\/iso-9806-konversion\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Conversion models of the collector parameters between EN 12975 and ISO 9806\" \/>\n<meta property=\"og:description\" content=\"As the physical models and parameters differ between EN 12975 and ISO 9806, the...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.velasolaris.com\/en\/handbuch\/polysun-designer\/producers\/solar-thermal-collectors\/iso-9806-konversion\/\" \/>\n<meta property=\"og:site_name\" content=\"POLYSUN\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/polysun.switzerland\/\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-20T14:28:30+00:00\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.velasolaris.com\\\/en\\\/handbuch\\\/polysun-designer\\\/producers\\\/solar-thermal-collectors\\\/iso-9806-konversion\\\/\",\"url\":\"https:\\\/\\\/www.velasolaris.com\\\/en\\\/handbuch\\\/polysun-designer\\\/producers\\\/solar-thermal-collectors\\\/iso-9806-konversion\\\/\",\"name\":\"Conversion models of the collector parameters between EN 12975 and ISO 9806 - 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