> for my simulation of a solar cooled building I want to determine the > solar fraction. The system works without backup (so, if solar power is > to low, room temperature rises above set temperature). This I calculate > the cooling load in a separate simulation, then I divide the produced > cooling power (which I suppose is entirely transmitted to the building) > by the cooling load. So far so well.
By definition, your solar fraction is identically one. There is no system providing back-up - you said the temperature of the building rises - so therefore all cooling that is done is done by solar. You can't just calculate the building cooling load in another simulation without the solar and then divide the cooling load met in one system by the cooling load met in another simulation - with differing temperatures the loads will not be the same - they may be close but they will not be the same. Why don't you add a secondary cooling system to meet the loads during peak periods and then calculate the solar fraction as 1 - (load met by auxiliary / total load met). As to your second question, instantaneous solar fractions are worthless and shoudn't be used in systems that have any sort of capacitance. They can range from -Infinity to Infinity. Only integrated solar fractions are worth calculating and reporting. Jeff Jeff Thornton President - TESS, LLC 2916 Marketplace Drive - Suite 104 Madison WI 53719 USA Phone: 608-274-2577 Fax: 608-278-1475 E-mail: [EMAIL PROTECTED] Web: www.tess-inc.com _______________________________________________ TRNSYS-users mailing list [email protected] https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
