can any one guide me how to find solar sunhour/day using solar irradiation values for a particular site and  finding optimum angle of module facing in order to get maximum in fixed mounting

To find Sunhours/day, 1. u need to have the solar irradiance values for every 10 minutes intervals of the day. 2. Note the time interval for which solar irradiation remains significant say..200w/m2 and above for the day. 3.Multiply this time interval (in hrs) with the average of the irradiance values noted throughout the day. 4. u will get the incident solar energy (kwh/m2) 5. Now when we divide this incident solar energy by the reference irradiance which is 1KW/m2 to get the no of peak sun hours.

I suggest to try PVGIS database or PVsyst software.

Sounds to me that NABSEP training would be of value??

thanks dinesh more and abdul aziz baraz can i use nasa solar data as base what are the latest measuring instruments available for site survey condition

You solar 'professionals" are scaring the crap out of me... I guess not all countries have permiting and inspections.

Hi Mark,

I fail to understand how permitting and inspection would impact the expected solar sunhour/day of a site? Maybe you can explain.

If in the US, go to NREL website, then National Solar Radiation Database to obtain TMY3 (Typical Mean Year) data from hundreds of sites. Each dataset is composed of numerous years of data, giving the typical mean year data.
Finding the optimum tilt angle depends upon solar radiation data, spacing (closeness of rows of PV modules), and environmental shading. Using software such as PVsyst can allow you to define the system, and then run simulations with different row spacing and tilt angles to determine the optimum angle.