Solar Water Heating: Collector library bug and auxiliary GAS heater

We would like to simulate the solar water heating system with an auxiliary GAS heater and storage tank for residential applications. How to do it with SAM? Is it possible to use SAM to model it with the same heater volume and temperature setpoint as for the auxiliary Electric heater, and later to convert all the auxiliary electric usage to BTU as Natural Gas consumption?

Another question, on the SWH System page, when we use Choose from library, we can not select the collectors. Nothing shows up to select (no dropdown list box there). When we use Search collector by name, no matter what to type in the name box, always no match. Did I miss something to connect the library?

SAM's solar water heating model currently only models an electric auxiliary heater because the financial models are for systems that displace electricity purchases rather than gas purchases. Your approach may work, although you may also need to adjust the Auxiliary Energy Factor and Auxiliary Max Power, and I do not have values to recommend for those.

There is a bug in SAM 2012.5.11 that causes the collector library to not display correctly on the SWH system page. We will fix that in the next update. In the meantime, you can extract the exelib.zip file ( ZIP 17 KB ) to your SAM installation folder (c:\SAM\2012.5.11 by default in Windows). When you extract the zip archive, respond to the prompts to copy the files their original folders and to replace existing files. There should be four files in three folders.

Best regards,
Paul.