[TRNSYS-users] Tank losses in general and Type4

[Mateo de Guadalfajara]

Dear Michael Diekerhof.

I suppose that you already have a transys model with at least: solar
collector, solar field pump with control sistem, tank storage, auxiliary
source and a variable demand.

To study the possitive effect of increasing the size of the system you can
use constant design ratios for the equipments and increase the annual
demand.

I use at least three important ratios.
   1) RAD (Ratio Area Demand) which is the area of solar collector divided
by the annual demand. (m2 / (MWh/a)) {ex 0,5}
   2) RFA (Ratio Flow Area) which is solar field flow divided by the solar
field area ((m3/h)/m2) {ex.0,020}
   3) RVA (Ratio Volume Area) which is the volume of the seasonal storage
divided by the size of the solar field (m3/m2). {ex. 2}

Keep these three ratios constant and change the annual demand. Sistems with
different size will be simulated and an increase of efficiency in the
seasonal storage will be seen.

http://www.sciencedirect.com/science/article/pii/S1876610212016116

Greetings,
               Mateo de Guadalfajara


2013/1/13 Michael Diekerhof <Michael.diekerhof at web.de>

> Dear all,
>
> I´m working with Type 4 to simulate a stratified storage tank.
>
> I have a question due to my results. If the storage volume (liters)
> increases of course the absolute tank losses (Wh) are getting higher as
> well. But how can i show that the relative value decreases if the storage
> tank gets bigger? The literature says, that the relative tank losses
> decrease with a higher tank volume since the relation of volume to surface
> increases.
>
> But even if I compare the "tank losses" to the "energy from heat source",
> the relative value gets higher with a bigger storage tank.
>
>
> I am very thankful for any suggestions to answer this question.
>
> Best,
> Michael
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