[TRNSYS-users] (PLEASE)optimization of a solar heating system combined

Wed Apr 13 21:56:52 PDT 2016

You can use GenOpt optimization for your solar collector - heat pump case study. The result you obtain depends on the value of the optimization goal function. Also, bear in mind that the performance of your system depends on the temperature levels and mass flow rates in the system. If the domain (i.e. boundary values of the solar collector area) is low enough, you should be fine with a flow rate of the pump for the solar loop set as a parameter (constant), otherwise, you must make this a function of optimization variable(s).
Also, peak your optimization goal functions carefully, the change of its value could not be so sensitive to the change of input parameters, which could lead to local (instead of global) optimum values. If you have more than one optimization variables, your goal function must be a mathematical relation of all of them, or run optimizations for each one and compare solutions. I would also recommend running a parametric analysis, so you know you are not stuck on a local minimum.
Marko 

      From: "trnsys-users-request at lists.onebuilding.org" <trnsys-users-request at lists.onebuilding.org>
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Today's Topics:

  1. Re: (PLEASE)optimization of a solar heating system combined
      with dual-source heatpump (Jeff Thornton)
<I want to find the best configuration of the system (include the area of the collectors, the angle of azimuth&dip of the collector, the constant flowrate of the collectors, the volume of the storage tank ) .when i simulated it in trnsys and genopt using PSO ,i tried to set the object function as the sum of  energy consumption in a year or the life circle cost of the system ,it turned out that the optimised area of collector is awalys to be the low limit of the collectors range i set in the genopt, may be it is  the truth,i am confused.>Set the tank volume to something reasonable with typical flow rates.  Set the collector slope to the latitude and the azimuth facing the equator.  Run a simple parametric study and look at the life cycle cost of the system as a function of the collector area.  It is VERY possible that the system will show increasing life cycle cost with increasing collector area - especially in a climate without a great solar resource.<Has anyone has the experience of optimization in similar system?how to confirm the best area of collector of the system?>We do optimizations on systems like this all the time but we don't ever start with a 5 variable optimization.  We'll use the Hooke-Jeeves algorithm on the tank volume and array area to get us in the right ballpark (with slope = latitude and south facing collectors at standard flow rates).  Once you are in the ballpark then you can expand to more variables and have some hope of finding a solution with that many variables. Jeff  ---
Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577  Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton at tess-inc.com
On 04/13/2016 9:31 am, Dr Yi Zhang wrote:
I am not sure if the PSO in GenOpt is a multi-objective algorithm... if not, you need to set the weighting between the two objectives "right" in order to get the desired result. Try jEPlus+EA for a multi-objective approach, which will show you the trade-off between performance and cost: http://www.jeplus.org/wiki/doku.php?id=docs:jeplus_ea:features Seeing  the trade-off will help you answer your second question, too. Regards, Yi From: TRNSYS-users [mailto:trnsys-users-bounces at lists.onebuilding.org] On Behalf Of Free
Sent: 13 April 2016 14:47
To: trnsys-users
Subject: [TRNSYS-users] (PLEASE)optimization of a solar heating system combined with dual-source heatpump Dear allI am now doing a project named "optimization of a solar heating system combined with dual-source heatpump(dual-source:water in storage tank  and outdoor air)" in trnsys for my master degree thesis, the system is just used for space heating in heating season at a high and cold area where the solar radiation is not so good.The schematic diagram of the system is as follow:I want to find the best configuration of the system (include the area of the collectors, the angle of azimuth&dip of the collector, the constant flowrate of the collectors, the volume of the storage tank ) .when i simulated it in trnsys and genopt using PSO ,i tried to set the object function as the sum of  energy consumption in a year or the life circle cost of the system ,it turned out that the optimised area of collector is awalys to be the low limit of the collectors range i set in the genopt, may be it is  the truth,i am confused. another question which is really important to me:Has anyone has the experience of optimization in similar system?how to confirm the best area of collector of the system?any advice is much appreciated.Warebest regards  
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