{"id":6741,"date":"2024-11-29T12:55:16","date_gmt":"2024-11-29T12:55:16","guid":{"rendered":"https:\/\/workhouse.sweetdishy.com\/?p=6741"},"modified":"2024-11-29T12:55:16","modified_gmt":"2024-11-29T12:55:16","slug":"efficiency-parameters-conversion","status":"publish","type":"post","link":"https:\/\/workhouse.sweetdishy.com\/index.php\/2024\/11\/29\/efficiency-parameters-conversion\/","title":{"rendered":"Efficiency parameters conversion"},"content":{"rendered":"\n

In the equations representing the performance of the solar collectors presented so far, the inlet fluid temperature is used. In some European standards, however (e.g. EN 12975-2: 2006), the average temperature is used, T<\/em>m<\/sub>, defined as the arithmetic average of the inlet and outlet temperatures [(T<\/em>i<\/sub> + T<\/em>o<\/sub>)\/2] and the efficiency is plotted against (T<\/em>m<\/sub> \u2212 T<\/em>a<\/sub>)\/G<\/em>t<\/sub>. In this case the collector instantaneous efficiency is given by:<\/p>\n\n\n\n

\"image\"(4.35)<\/strong><\/p>\n\n\n\n

where \"image\" is the mean temperature collector efficiency factor.<\/a><\/p>\n\n\n\n

If the temperature rise through the collector is linear with distance, which is correct for most applications \"image\" and the collector efficiency factor given by Eq. (3.48)<\/a>.<\/p>\n\n\n\n

Therefore, in the case where\u00a0T<\/em>m<\/sub>\u00a0is used for the collector performance, Eq.\u00a0(4.35)\u00a0plots as a straight line and the intercept\u00a0\"image\"\u00a0and slope\u00a0\"image\"\u00a0of the curve are related to\u00a0F<\/em>R<\/sub>(\u03c4\u03b1<\/em>)n<\/sub>\u00a0and\u00a0F<\/em>R<\/sub>U<\/em>L<\/sub>, respectively, by eliminating\u00a0\u03b7<\/em>\u00a0and\u00a0T<\/em>o<\/sub>\u00a0from Eq.\u00a0(4.2)\u00a0and\u00a0(4.4)\u00a0and using the equation for\u00a0T<\/em>m<\/sub>:<\/p>\n\n\n\n

\"image\"(4.36a)<\/strong><\/p>\n\n\n\n

\"image\"(4.36b)<\/strong><\/p>\n\n\n\n

And<\/p>\n\n\n\n

\"image\"(4.36c)<\/strong><\/p>\n\n\n\n

\"image\"(4.36d)<\/strong><\/p>\n\n\n\n

To apply these equations the fluid flow rate through the collector must be known.<\/p>\n\n\n\n

Similarly in the case where T<\/em>o<\/sub> is used for the collector performance and the efficiency is plotted against (T<\/em>o<\/sub> \u2212 T<\/em>a<\/sub>)\/G<\/em>t<\/sub>, sometimes applied in the case of air collectors, the collector instantaneous efficiency is given by:<\/p>\n\n\n\n

\"image\"(4.37)<\/strong><\/p>\n\n\n\n

Equation\u00a0(4.37)\u00a0also plots as a straight line and as above, the intercept\u00a0\"image\"\u00a0and slope\u00a0\"image\"\u00a0of the curve are related to\u00a0F<\/em>R<\/sub>(\u03c4\u03b1<\/em>)n<\/sub>\u00a0and\u00a0F<\/em>R<\/sub>U<\/em>L<\/sub>, respectively, from:<\/p>\n\n\n\n

\"image\"(4.38a)<\/strong><\/p>\n\n\n\n

\"image\"(4.38b)<\/strong><\/p>\n\n\n\n

And<\/p>\n\n\n\n

\"image\"(4.38c)<\/strong><\/p>\n\n\n\n

\"image\"\/<\/figure>\n","protected":false},"excerpt":{"rendered":"

In the equations representing the performance of the solar collectors presented so far, the inlet fluid temperature is used. In some European standards, however (e.g. EN 12975-2: 2006), the average temperature is used, Tm, defined as the arithmetic average of the inlet and outlet temperatures [(Ti + To)\/2] and the efficiency is plotted against (Tm \u2212 Ta)\/Gt. In this case […]<\/p>\n","protected":false},"author":1,"featured_media":6689,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[700],"tags":[],"class_list":["post-6741","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-4-performance-of-solar-collectors"],"jetpack_featured_media_url":"https:\/\/workhouse.sweetdishy.com\/wp-content\/uploads\/2024\/11\/solar-energy-2.png","_links":{"self":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6741","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/comments?post=6741"}],"version-history":[{"count":1,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6741\/revisions"}],"predecessor-version":[{"id":6742,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/posts\/6741\/revisions\/6742"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media\/6689"}],"wp:attachment":[{"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/media?parent=6741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/categories?post=6741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/workhouse.sweetdishy.com\/index.php\/wp-json\/wp\/v2\/tags?post=6741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}