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Chou, My apologies for the delay in getting back to you. 1. As you mentioned in the first simulation with Type 56----to get a basic idea of how much energy the building will consume, use the VENTILATION Type with outside air and use the COOLING Type to define set up temperature. I set the VENTILATION Type with the conditioned air (temperature 16C), I think the cooling load will change, but the results don't change significantly (<10%). Also in the VENTILATION Type, I wonder the air change rate refers to the fresh air or the mixed air (flow of fresh + return air) if the VENTILATION is set up as outside.Type56's VENTILATION is quite simple; it is just an air flow rate (specified in air changes in v16, and specified as either an air change rate or a mass flow rate in v17) with the temperature and RH that you specify. There is no assumption at all about whether it is outside air or return air. From your description of adding a VENTILATION type with a temperature of 16C, my guess is that your cooling load was reduced by adding a cool stream of air to the room (provided that your room setpoint is above 16C of course). The size of the reduction would depend upon how much air you added. If you specified a small amount of air, the reduction would be small. If you specify the conditions of the VENTILATION types as "outside" then Type56 simply adds the quantity of air that you specified and uses the ambient conditions that it already knows from the ambient temperature and RH inputs to the Type. In this case, you are adding only the flow of fresh air. In order to add a mixed flow, you would have to specify the air change rate of the mixed flow and the conditions of the mixed flow, probably as additional INPUTS to Type56. 2. In the file of BALANCE summary, the BAL_ENERGY is supposed to be zero, according to the Manual. However my results indicate that this item is up to 10^6 kJ, and it doesn't equal to the sum of the other items. And there is not too much details about it on the manual.I would need to take a look at the input file in order to determine whether or not this is expected. 3. I try to use Type 53 + Type 52 as the AC components of the Type 56, But when I run the model, an error occurs, which says,the fact that the filename is blank in the error message is probably an indication that you didn't specify a performance data file for Type53. Try opening Type53 and selecting the "External Files" tab to make sure that a file is referenced. An example file can be found in: .Trnsys17\Examples\Data Files\Type53-ParallelChillers.dat. If you are using Trnsys16, I can send you a copy of the file. Kind regards, David -- *************************** 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 d.bradley@tess-inc.com http://www.tess-inc.com http://www.trnsys.com |