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solar collector for domestic water heater

asked 2017-06-27 12:14:35 -0500

kabot gravatar image

updated 2017-07-09 12:59:59 -0500

I am modeling a solar thermal collector to heat a storage tank, with an auxiliary resource to a instantaneous water heater. Pretty much like the example file, but with only 1 collector.

I am having some issues here and I would appreciate very much some help:

  • As a report, I am having almost 11000 warnings: Warning * GetSpecificHeatGlycol: Temperature out of range (too low) for fluid [WATER] specific heat * *** * ~~~ * This error occurred 56 total times; *** * ~~~ * during Warmup 0 times; *** * ~~~ * during Sizing 0 times. *** * ~~~ * Max=-1.280499E-002 {C} Min=-1.280499E-002 {C}

Warning * GetDensityGlycol: Temperature out of range (too low) for fluid [WATER] density * *** * ~~~ * This error occurred 12 total times; *** * ~~~ * during Warmup 0 times; *** * ~~~ * during Sizing 0 times. *** * ~~~ * Max=-1.280499E-002 {C} Min=-1.280499E-002 {C}


Warning * GetSpecificHeatGlycol: Temperature out of range (too high) for fluid [WATER] specific heat * *** * ~~~ * This error occurred 10321 total times; *** * ~~~ * during Warmup 0 times; *** * ~~~ * during Sizing 0 times. *** * ~~~ * Max=211.007203 {C} Min=125.007536 {C}


Warning * GetDensityGlycol: Temperature out of range (too high) for fluid [WATER] density * *** * ~~~ * This error occurred 1280 total times; *** * ~~~ * during Warmup 0 times; *** * ~~~ * during Sizing 0 times. *** * ~~~ * Max=193.355078 {C} Min=100.035962 {C}

How would I be able to solve it? I am trying to solve it for two days now and still didn't figured it out.


Issue 2: How would I be able to simulate one Plant Loop (solar collector loop) in the source side, and an auxiliary heater that would send the water direct to the demand on the use side of the water heater (mixed)?

I am for now working with two Plant loops but indeed I think would be more efficient if the use side were an auxiliary heater direct to the demand.

I can upload my idf file if needed.

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answered 2017-07-12 04:17:02 -0500

ezeraj gravatar image

1st issue - From the errors i can infer that the simulated values exceed the limits of the medium used.I have no experience in Energy Plus but I have encountered similar erros while using Dymola, by giving the correct medium as input I am sure you would solve this error.

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Dear ezeraj, thank you very much for your contribution! Indeed, I could notice this was the problem, but wasnt able to solve it correcting the medium, once I think this is an active system where the water itself is running the system, instead of any type of glycol. In another hand, I might have misunderstood how it works. I changed the maximum and minimum temperatures allowed on the loop in order to reduce the errors, but indeed I think this is not the solution at all (just a makeup to reduce the errors).

kabot gravatar imagekabot ( 2017-07-19 03:35:02 -0500 )edit

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Asked: 2017-06-27 12:14:35 -0500

Seen: 315 times

Last updated: Jul 12