[esp-r] Re: slab-on-grade hydronic floor in a solar heating system

[Geissler Achim]

Dear Ida


a)      The "dangerous" warning can be ignored, however, most likely the results file does not have any useful content

b)      Are there error messages during simulation for your plant net without the fourth connection? Have you tried reducing time step (especially, if there are warning messages in regard to water temperatures)? Could you give *your* net with component types (how many nodes in the tank, for example)?

A very small plant network with the components you describe will be very "quick", thermally. Try one minute plant time steps. Also, the coupling with the building via slab on grad hydronic floor may make short building side time steps necessary (try 10 ts/h building and 6 ts/building_ts plant).

Best
Achim



Von: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-bounces at lists.strath.ac.uk] Im Auftrag von Ida Auråen
Gesendet: Montag, 8. April 2013 15:56
An: esp-r at lists.strath.ac.uk
Betreff: [esp-r] slab-on-grade hydronic floor in a solar heating system

Hello.

I have a question regarding slab-on-grade hydronic floor under the "plant and systems" menu.

I'm trying to create a solar heating system with the following components:
1) "simplified flat plate solar collector",
2) "Variable speed domestic WHC pump" and
3) "slab-on-grade hydronic floor".

I have linked all these three components and defined where heat is being injected in the zone. I have also set up the control loop with sensor, actuator and defined period data. But when I want to run a simulation and check the results I just get a message saying "Library is incomplete or corrupt... Do you want to - attempt to continue (DANGEROUS) or - give up?"

I don't understand what is wrong.

I know that a former student at my University has built up a similar system, instead of a hydronic floor, he used a hot water tank, and he managed to run simulations. He had 4 connections, and not 3 as I have. But I don't understand why one would the fourth connection..?

He had the following connections:

recieving comp. - sending comp.:

Solar collector - Pump (mass frac.: 1, temp: 0)
Hot water tank - Solar collector (mass frac.: 1, temp: 0)
Pump - Hot water tank (mass frac.: 1, temp: 0)
Hot water tank - Pump (mass frac.: 0, temp: 20)

He told me that he found a similar connection in one of esp-r exemplar models, therefore he implemented it in his model. But I haven't found it myself.

My question is:

What kind of connections are needed to run simulations for a system with a solar collector, pump and hydronic floor?

I am still a novice using ESP-r, so any replies would be appreciated.

Regards, Ida Auråen


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