HeatExchanger:FluidToFluid - Design and Sizing

asked 2016-06-13 11:38:12 -0600

nielex's avatar

updated 2016-06-13 11:41:01 -0600

I try to simulate a waterside economiser application with a HeatExchanger:FluidToFluid with a given design dT ((supply side inlet temperature - demand side outlet temperature) should be 2°C). I did some calculations and set some different parameters but I never gets close to my design dT. Does anyone have some experience with the design and sizing of HX?

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Can you post a little more information about how you're sizing the two plant loops? As long as your supply loop design exit temperature is 2° higher than your demand loop design exit temperature, I would think the dT should be realized at max load.

Adam Hilton's avatar Adam Hilton  ( 2016-06-15 11:58:08 -0600 )edit

Design goals HX: 18/12°C, 16/10°C. Based on HX fundamentals the LMTD ( = Tsup,in - Tdem,out) should be 2°C. I have hard-sized the supply flow rate, demand flow rate and the UA (UA = Q/LMTD, Q ~ 2412 kW). DesignLoopExitTemperature = 12 °C and LoopDesignTemperatureDifference = 6 (Sizing:Plant, CHW Loop), DesignLoopExitTemperature = 10 (16) (Sizing:Plant, Condenser Loop). DeltaTLoopToLoop,Des = 8°C (EngRef page 542). But rather for me DeltaTLoopToLoop,Des should be the LMTD (EngRef 9.78) Correct? Furthermore using this values I also got some temperature peaks (increase of CHW Loop Supply outlet

nielex's avatar nielex  ( 2016-06-17 10:12:52 -0600 )edit