Decreasing heat in glass porch
You can call one of the tinting places in your area and ask them to put up some ceramic film that will reflect up to 95% of heat. That's what they use on cars now days and it works but kind of pricey. What it does, is blocking UV and IR from heating up your floor and furniture  and unlike the regular tint/film, it will keep those window (glass) cool as well, preventing from radiant heat from seeping through.