Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question
3

where is the mathematical model of Dehumidifier:Desiccant:NoFans

asked 2018-05-30 06:27:55 -0600

Dr. Fan gravatar image

updated 2018-05-30 10:28:40 -0600

Hello everyone, i have some difficulty to find the mathematical model of the object Dehumidifier:Desiccant:NoFans contained in EnergyPlus, even i have went through the documents of "InputOutputReference" and "EngineeringReference". As specified in the document of "InputOutputReference" , the object of Dehumidifier:Desiccant:NoFans allows the users to use either the default performance model or user specified performance model. As i currently i have no user specified model, so i have to use the default performance model.The default performance model is defined in the "InputOutputReference" by a performance curve of the following form:image description. This equation includes many coefficients (i.e. C1, C2,C3 and C15), but the values of these coeffieicnts are not given.
Is there anyone can give me some hints to the values of these coefficients. I quite appreciate if anyone can give me some feedbacks. Thank you in advance.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
1

answered 2018-05-30 15:11:57 -0600

updated 2018-05-30 15:13:07 -0600

You can find the hardcoded coefficients in the source code.

See DesiccantDehumidifiers.cc#L2154:L2169

You'll notice that the hardcoded coefficients are 0-indexed while the engineering reference is 1-indexed, so offset it by 1...

// Calculate leaving conditions
TC0 = -38.7782841989449;
TC1 = 2.0127655837628;
TC2 = 5212.49360216097;
TC3 = 15.2362536782665;
TC4 = -80.4910419759181;
TC5 = -0.105014122001509;
TC6 = -229.668673645144;
TC7 = -0.015424703743461;
TC8 = -69440.0689831847;
TC9 = -1.6686064694322;
TC10 = 38.5855718977592;
TC11 = 0.000196395381206009;
TC12 = 386.179386548324;
TC13 = -0.801959614172614;
TC14 = -3.33080986818745;
TC15 = -15.2034386065714;

ProcAirOutTemp = TC0 + TC1 * ProcAirInTemp + TC2 * ProcAirInHumRat + TC3 * ProcAirVel + TC4 * ProcAirInTemp * ProcAirInHumRat +
                 TC5 * ProcAirInTemp * ProcAirVel + TC6 * ProcAirInHumRat * ProcAirVel + TC7 * ProcAirInTemp * ProcAirInTemp +
                 TC8 * ProcAirInHumRat * ProcAirInHumRat + TC9 * ProcAirVel * ProcAirVel +
                 TC10 * ProcAirInTemp * ProcAirInTemp * ProcAirInHumRat * ProcAirInHumRat +
                 TC11 * ProcAirInTemp * ProcAirInTemp * ProcAirVel * ProcAirVel +
                 TC12 * ProcAirInHumRat * ProcAirInHumRat * ProcAirVel * ProcAirVel + TC13 * std::log(ProcAirInTemp) +
TC14 * std::log(ProcAirInHumRat) + TC15 * std::log(ProcAirVel);
edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

 

Question Tools

1 follower

Stats

Asked: 2018-05-30 06:27:55 -0600

Seen: 102 times

Last updated: May 30 '18