Mavi, there are a number of things that could be a problem. The two most common ones are that you have to assign heat exchanger nodes to tank nodes (using a pull-down menu in the lower right hand corner of the window). Sometimes when you change from one heat exchanger type to another, they have different numbers of nodes and if you do not assign all the heat exchanger nodes, they can end up getting assigned to tank node 0 (which doesn't exist). Check the heat exchanger node assignments first. another problem comes if you have defined a large heat exchanger. The volume taken up by the heat exchanger is removed from the tank nodes. If you have a big heat exchanger and a small tank, you can end up with the heat exchanger taking up more volume than is available in the tank. If neither of these two solve your problem, please send me the project file and tank data file and I will have a look in the code, Kind regards, David On 6/24/2010 02:33, Mavi Cambronero Vázquez wrote:
-- *************************** David BRADLEY Principal Thermal Energy Systems Specialists, LLC 22 North Carroll Street - suite 370 Madison, WI 53703 USA P:+1.608.274.2577 F:+1.608.278.1475 bradley@tess-inc.com http://www.tess-inc.com http://www.trnsys.com |