The amount it displays when you hover over it is not accurate. This doesn't behave sufficiently like a vanilla heat generation entity for the game engine to understand it properly. The solar collectors will generate 0.1% of their max heat even at night, which is what you're seeing, but that's pretty negligible compared to the main effect. If you hook up some boilers or stirling engines to it on an isolated circuit you'll see it generating a lot more than 160W during the day.
There is some lag time when you first hook it up, because it takes some time to heat up the system enough to start generating energy. Heat Pipe 1 is not very powerful at transmitting heat over a distance, so keep the stirling engine or boiler as close as possible to your solar collectors rather than using a long pipe. You can link up a row of 4 or 5 solar collector 1s to each other end to end though. Another thing to keep in mind is that heat energy is used at a lower priority than wind or photoelectric solar. So if you're getting enough energy from wind and solar panels to meet all your demand, you won't consume any from a stirling engine or turbine. It will just save up the heat energy for later when you need the power (the same way that in vanilla you won't burn coal when your solar panels are meeting demand). The electrical grid display will only show power as generated if it is actually consumed, so when you have more than enough energy production it can appear that you're generating less energy per energy source than their max capability.
