Don't know of any module that produces 500 watts but that doesn't mean there isn't one. Theoretically, solar panels will produce full output when in a laboratory with the correct luminescence supplied. That is how they are rated. Angle towards the sun, time of day, and amount of available sunlight all factor into the output. Practically, my 235 watt module still is producing some power, albeit very little, at dusk and dawn. It will also make some power on cloudy and rainy days, but not near the rating watts. This is a polycrystalline cell module. Monocrystalline, especially thin film, will produce, relatively, more power in lower light conditions.
Yes, you can run an electric fridge with solar and sufficient batteries for storage. I'm using a small 120v dorm fridge that draws 80 watts when operating. I have 320 AH of batteries and a single 235 watt module. I have yet to test all of it out full time but I'm pretty confident it will work out well.
