03-01-2014, 05:49 AM
I have been playing around with the different parameters related to storage devices (across time-slices). I have two concerns with the STG_LOSS parameter:
, which is clearly lower than the ones according to VEDA/TIMES.
1) As VAR_ACT_s represents the energy stored at the beginning of time-slice s (p.229 of part II), wouldn't it be more rational to use G_YRFR_s-1 in the equation on p.230 of part II ?
2) A second, and more critical issue I have is that, when analyzing the numerical value of the storage losses, remarkably low values of losses occur which do not correspond to the ones I calculate by hand by following the equation on p.230.
As a test case, I use a storage device with STG_EFF equal to 1, and STG_LOSS equal to 0.25.
I used 4 seasonal time-slices (SU, FA, WI, SP, each lasting 25% of the year) and three daynite time-slices (D,P,N in that order, day and night representing 40% of the 'day', while peak represents 20%) => G_YRFR = 0.1 for WID and WIN, and G_YRFR = 0.05 for WIP.
The storage process is declared on the DAYNITE level as is the stored commodity. The storage device is only used in the winter (as I made sure that demand couldn't be reached without the storage device in the winter-peak).
I get the following values:
| Period | 2010 | 2010 | 2010 | |
| Attribute | Vintage\TimeSlice | WID | WIP | WIN |
| VAR_Act | 2010 | 0.000648133 | 3.153816015 | |
| VAR_FIn | 2010 | 3.1536 | 0.000648222 | |
| VAR_FOut | 2010 | 3.1536 | ||
| G_YRFR | 0.1 | 0.05 | 0.1 |
My calculations state that the activity variable of WIP (given all values of WID), should amount
| 3.134652504 |
As I increased the STG_loss parameter, the difference between what I calculate and the VEDA/TIMES results diverge stronger.
Does anyone has an idea what is going wrong here?