# Parameter Variations

A closer look on the results of dimensioning the base case leads to a comprehensive knowledge about the MaxLean system behaviour and the advantages of the concept. To gain insight into the influence the components have on the optimised system, a number of parameter variations were performed. For each variation a new optimisation procedure was carried out leading to different curves in the cost/savings diagram. Figure 3 gives an overview of the parameters varied and the results of the optimisation runs.

variation

* base case

• best points

Fig. 3. Cost benefit diagrams of the parameter variations. The triangular dots in the respective charts
represent the dimensioning of the base case. The circular dots are the associated best points, generated with
the varied parameters. a) Cost of solar collector: 100 % to 70 % of the initial price. b) Efficiency curve of
solar collector: , From a low efficiency to a high efficiency flat plate collector. c) Cost of storage tank: 100 %
to 60 % of the initial price. d) Insulation of storage tank: 7.5 cm to 17.5 cm. e) Variation of the rise in energy

prices. 1.3 %/a to 7.5 %/a.

– Portugal *

 Variation cost/benefit ratio [€/kWhprlmary] additional cost [€/a] primary energy savings [kWhpnmary/a] V store [m3] Acollecotr [m2] Base Case 0.077 347 4502 0.67 8.9 95 0.075 340 4552 0.67 9.2 cost of solar 90 0.072 328 4552 0.67 9.2 /£ / collector 85 0.069 322 4653 0.65 10 / € [% of initial 80 0.067 325 4863 0.69 11 cost] 75 0.064 312 4876 0.67 11.3 70 0.061 307 5032 0.67 12.4
 Table 1. Results of the optimised systems generated by dimensioning the MaxLean system with varying parameters.

 95 0.075 336 4502 0.67 8.9 90 0.072 326 4502 0.67 8.9 cost of 85 0.07 316 4502 0.67 8.9 € storage tank 80 0.068 306 4502 0.67 8.9 V/ [% of 75 0.066 295 4502 0.67 8.9 initial cost] 70 0.063 283 4476 0.67 8.8 65 0.061 270 4444 0.71 8.4 60 0.058 260 4444 0.71 8.4 0.075 0.091 428 4701 0.77 12 0 f insulation of a 0.1 0.084 398 4743 0.75 11 | storage tank n 0.125 0.08 371 4639 0.69 10.1 [m] 0.175 0.075 339 4517 0.65 8.8 rise in 3 0.066 296 4502 0.67 8.9 £ energy prices 5 0.049 218 4479 0.65 9 —J [%/a] 7.5 0.02 93 4594 0.67 9.5