The Assessment of Hydrogen Energy Systems for Fuel Cell Vehicles Using Principal Component Analysis and Cluster Analysis

Table 4

The correlation coefficient matrix.

	SO2	CO2	NO𝑥	CO	CH4	Dust	Waste water	Waste solids	Costs	Energy
SO2	1.0000	0.8688	0.9986	0.0513	−0.5662	0.7204	0.9996	0.9996	0.6932	−0.0717
CO2	0.8688	1.0000	0.8490	−0.3925	−0.8498	0.5394	0.8555	0.8557	0.7126	0.0552
NO𝑥	0.9986	0.8490	1.0000	0.0933	−0.5270	0.7439	0.9991	0.9991	0.6699	−0.0778
CO	0.0513	−0.3925	0.0933	1.0000	0.6754	0.2397	0.0739	0.0733	−0.1803	−0.1969
CH4	−0.5662	−0.8498	−0.5270	0.6754	1.0000	−0.0837	−0.5483	−0.5487	−0.6369	−0.0968
Dust	0.7204	0.5394	0.7439	0.2397	−0.0837	1.0000	0.7193	0.7189	0.3216	−0.0434
Waste water	0.9996	0.8555	0.9991	0.0739	−0.5483	0.7193	1.0000	1.0000	0.6873	−0.0783
Waste solids	0.9996	0.8557	0.9991	0.0733	−0.5487	0.7189	1.0000	1.0000	0.6875	−0.0782
Costs	0.6932	0.7126	0.6699	−0.1803	−0.6369	0.3216	0.6873	0.6875	1.0000	−0.4905
Energy	−0.0717	0.0552	−0.0778	−0.1969	−0.0968	−0.0434	−0.0783	−0.0782	−0.4905	1.0000