Hi,
I am working in a solar district heating simulation project and I am getting a solar collecotr efficiency over 64%, which is impossible. I am refering to the ratio between incident radiation to the collectors, and the energy gain by them:
total radiation on tilted surface: 1,93 MWh/m²/year
useful energy gain by collectors: 1,23 MWh/m²/year
So, I connected something erroneously, but I can not find the right way. I tried Quadratic Collector type1a and type1b and I got the same excessive efficiency.
In the first one TYPE1a the connections with weather data are the following:
Ambient temperature-->Ambient temperature
Total radiation on tilted surface-->Incident radiation
In type 1b the connection are the following:
Ambient temperature-->Ambient temperature
Total radiation on horizontal --> Total horizontal radiation
Sky difuse radiation on horizontal --> Horizontal diffuse radiation
Ground reflected diffuse radiation on horizontal --> Ground reflectance
Total radiation on tilted surface --> Incident radiation
Angle of incidence for tilted surface --> Incident Angle
Slope of tilted surface --> Collector slope
I really need to solve this problem, thanks.
Jordi