Solar Power Plants:OFF-GRID/Hybrid
Suppose you have installed solar panels with a peak power output capacity of 4000 Watts. In Summer at 12 noon how much power will this Generate?
I was expecting at least 80% that is 3200 Watts. But what I actually got was around 2200 Watts! Only about 55%! How do you explain this? The issue here is the rise in temperature of the solar panels of above 65 degree C. The panels were too hot to touch. Throwing water on the solar panels increases the output power (by about 10%) for few minutes. There is a second problem. If the Lithium Battery or the MPPT controller in the Inverter becomes hot (Ambient room temperature of 45 degree C plus heating in the Inverter or the Battery due to High load current), the charge controller and the BMS will try to reduce the amount of charging current down to zero to avoid the explosion of the battery. So, to improve matters:
- Hide the Inverter and the battery from Sun’s heat by keeping these inside a concrete building.
- Run water from a water tank on the solar panels when it is too hot in the noon. The panel also remains clean with out dust
- A water tank of say 1000 litres kept below in the shadow of the panels and a half hp motor pump can be used to auto-sprinkle the water. You may waste about 200 W power for the motor but may get an increase in PV power of about 400 W.
BOQ OF A SOLAR HYBRID INVERTER
- Solar Panel Frame
- Solar Panels say 5 kW
- DC-Distribution board (DC DB)
- Lightening Arrestor
- Grounding Cylinders for earthing
- Earthing copper wire
- AC-Distribution Board for Grid Connection and AC-DB for Load connection with MCBs
- Transformerless High Efficiency Inverter say 5 kW
- Zero Export to CT Accessories
- CAN/RS485 Connecting Communication Cable
- Lithium Ferro-Phosphate Battery that is compatible to the Inverter for CAN/485 Signaling say with a capacity 10 kWh
Earthing Cylinders. At least 3 earthing cylinders of 2 m long will be needed.
What is Better, Mono-Crystalline or Poly-Crystalline solar panels?
Mono-Crystalline Panels (545 Watts) are desired providing the price per watt is the same as that of Poly-Crystalline panels (330 Watts). At times you may find the Poly-Crystalline panels suitable if you want to use the 2 MPPT strings on the Inverter to match the MPPT input voltage Range. Mono and Poly will generally provide the same performance for a given price. One disadvantage of the Poly will be that it will consume more space and a slight increase the Frame cost.