ZHM suffered thermal decomposition until 553[degrees]C, with a char residue 61%; however, at 453[degrees]C, this sample had only 62% of its weight.
X-ray diffraction patterns: (a) sodium myristate, (b) copper hydroxide nitrate (CHN), (c) copper hydroxide nitrate intercalated by the anion myristate, produced by indirect method (CHN[myristate] indirect), (d) copper hydroxide myristate, produced by direct method (CHM), (e) zinc hydroxide nitrate (ZHN), (f) zinc hydroxide nitrate intercalated by the anion myristate, produced by indirect method (ZHN[myristate] indirect), zinc hydroxide myristate, produced by direct method (ZHM).
(b) ZHS, (c) ZHN(stearate) indirect, (d) ZHM, (e) ZHN(myristate) indirect, (f) ZHA, (g) ZHN(azelate) indirect, (h) ZHP.
2002), an empirical solar model (Zhang-Huang Model, or ZHM for short) was developed that correlated total solar radiation to the cloud cover, change in dry-bulb temperature over the past three hours, relative humidity, and wind speed (see Equation 3).
For this project, the ZHM has been constrained with the addition of maximum and minimum thresholds to prevent it from predicting solar radiation that is outside of physical reality, i.e., either exceeding the clear sky or zero radiation when the sun is above the horizon.
The original ZHM derived a single set of coefficients based on regression analysis of 1993 measured solar data in two Chinese cities (Zhang et al.
Although the ZHM with the regional coefficients has been shown to produce reasonable estimates of monthly and annual solar radiation, the hourly solar profiles tend to show statistical noise that is most apparent on clear days without any clouds, when an analytical model indicates there should be a regular bell-shaped hourly profile (see top plot of Figure 8 showing the unmodified hourly profiles from the ZHM).
To improve the hourly solar profiles in the IWEC2 weather files, the ASHRAE 2009 Clear Sky Model (Gueymard and Thevenard 2013), or ACSM09 for brevity, is used to recalculate the hourly distribution of global horizontal radiation while leaving the total daily solar radiation computed by the ZHM unchanged.
Since both projects used essentially the same source data, the other remaining difference between the two are the models used to estimate solar radiation: the Kasten model for IWEC and the ZHM for IWEC2.
It was understood that the accuracy of the ZHM depended a great deal on having the appropriate solar coefficients and ideally tuned to measured solar data for the location.