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Gary, There is a bit of room for interpretation in your question; I'm not sure whether the setpoint to which you refer is the temperature of the chilled water that the absorption chiller is providing or whether it is the room temperature that you want to maintain. I am guessing that you want to change the room temperature setpoint and that you have defined your zone temperature using the HEAT and COOL types inside TRNBuild. If that is the case, then here are the steps you need to take: 1. turn OFF the automatic HEAT and COOL types in TRNBuild so that the zone temperature floats. 2. in the Simulation Studio, define a thermostat (Type108 would be a good choice) that watches the zone temperature and has the same set point schedule that you previously defined in TRNBuild. The output of this thermostat model is going to be the control signal input to your cooling equipment. 3. decide how you want to remove energy from the sapce (fan coil, radiant cooled slabs, etc.) and choose an appropriate model. 4. define a water loop that includes a pump, the delivery device, a thermal storage tank (Type534 would be a good choice), and the absorption chiller. 5. connect the cooling signal output of the thermostat model to both the pump and the chiller control signal. One work of caution: in most circumstances, the absorption chiller is not directly connected to the delivery device. There are usually two loops. If there are multiple energy delivery devices then they are usually on a secondary loop while the absorption chiller is on a primary loop (http://www.nanomagnetics.org/chilledwatertips/constant_volumen_constant_speed.php) Alternatively, you can have a situation where there is a chilled water distribution loop with a pump that draws chilled water from a tank, passes it to the load, and returns warmer water to the tank. The pump runs based on a thermostat that watches the zone temperature. The chiller is on a separate loop that pumps water from the tank, cools it down with the chiller and returns it to the tank. A thermostat that watches the tank temperature and turns on the chiller and a pump when needed. There is a tutorial online that would be well worth reading; I think it will fill in some of the gaps in what I have explained above. http://sel.me.wisc.edu/trnsys/downloads/tutorials_and_examples/tlc_tutorial.pdf Best, David On 9/30/2012 04:53, KUM GARY wrote:
Hi all, -- *************************** 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 |