Dear all,
I am using Trnsys17 and I have some queries on Type 666.
1. What is the difference between Chilled Water Inlet Temperature and Cooling Water Temperature? Does this correspond to chilled water return temp (entering) and chilled water supply temp (leaving) respectively?
2. How are Chilled Water Inlet Temperature and Cooling Water Temperature different from CHW Set Point Temeprature?
3. Similarly what is the difference between Chilled Water Flowrate and Cooling Water Flowrate?
4. I have a specific chiller which I intend to input. How do I convert the biquadratic coefficients for the performance curves into text file for full and part load. Link to chiller specs http://simulationresearch.lbl.gov/modelica/releases/v2.1.0/help/Buildings_Fluid_Chillers_Data_ElectricEIR.html#Buildings.Fluid.Chillers.Data.ElectricEIR.ElectricEIRChiller_Carrier_19EX_5208kW_6_88COP_Vanes
Thank you :)
Kindest regards,
Gab
?Dear *GABRIEL*
*1)Chilled water inlet temperature is t**he temperature of the chilled
water stream entering the chiller.It is the temperature of the fluid
returning from load e.g. air handling unit.*
*whereas cooling water temperature is the the temperature at which the
cooling water flow stream enters the chiller from cooling tower to provide
cooling in its condenser unit.*
*2)Chilled water set point temperature is the the set point temperature for
the chilled water stream. If the chiller has the capacity to meet the
current load, the chiller will modulate to meet the load and chilled water
stream will leave at this temperature.*
*So chilled water inlet temperature is at which chilled water from load
enter the chiller and chilled water set point is the temperature at which
you want the chilled water from chiller to enter in load.*
*3)Most of the chiller manufacturing companies provides softwares to check
chiller performance by varying chilled water inlet temp,cooling water temp
etc.Using that software you can create your own data file.for example check
this link*
http://www.ppiway.com/chillerperformance/index.html
*I hope i answered your question.*?
?M Wajahat Khan?
--
Gab,
I would also like to mention something that I did that can be replicated with not too much difficulty for the external TRNSYS data files for Type666.
You mentioned that you were looking at the EnergyPlus?s Chiller:Electric:EIR. This is a convenient place to start because of the numerous chiller data information in the C:\EnergyPlusV8-4-0\Chillers.idf file (I recommend viewing this in the IDF Editor). Like the Type666 chiller the performance of this E+ model is also based on the relevant temperatures and EIR.
Cooling capacity as a function of CW supply temp and entering condenser temp curve = a + b*CWS + c*CWS**2 + d*ECT + e*ECT**2 + f*CWS*ECT
CWS = supply (leaving) chilled water temperature(C) ECT = entering condenser fluid temperature(C)
Electric Input Ratio (EIR) as a function of temperature EIR = 1/COP curve = a + b*CWS + c*CWS**2 + d*ECT + e*ECT**2 + f*CWS*ECT
CWS = supply (leaving) chilled water temperature(C) ECT = entering condenser fluid temperature(C)
Electric Input Ratio (EIR) as a function of Part Load Ratio (PLR) EIR = 1/COP quadratic curve = a + b*PLR + c*PLR**2
PLR = part load ratio (cooling load/steady state capacity)
In the *.idf file are the the coefficients and temperature ranges for the above equations for the 162 different chillers. What my colleague did was create a spreadsheet that takes the confidents and tabulated different temperatures and performance, so he could plot the chiller curves. What I did was use the tabulated temperatures and performance to make the TRNSYS data files. Now, I can simply plug in the coefficients and temperature ranges from that E+ file, and I automatically get the TRNSYS Type666 data files. I cannot share the spreadsheet tool, yet it does not take too much effort or time.
Please let me know if you have any questions while this is still fresh in my mind.
Cheers,
Matt
P.S. TRNSYS/TESS development team: For the wish list, I would like to put a request for a chiller model based on the E+ Chiller:Electric:ReformulatedEIR model that uses performance maps based on leaving condenser water temperature (oppose to entering).
https://energyplus.net/sites/all/modules/custom/nrel_custom/pdfs/pdfs_v8.4.0/EngineeringReference.pdf
(page 594)