It is a hot one today. In the three years I've been in Midway, today's forecast of 98 degrees is the highest I can remember. When you have a plant in a greenhouse it obviously can get even hotter. Yesterday we got to 97 degrees and the greenhouse cooling system did its job fairly well.
At the old house I just used a sprinkler that could spray about 30 feet put it did it with a fairly fine mist. You don't want a lot of water. Just enough to lightly dampen the leaves in a way that it can fairly quickly evaporate. I used a hose end timer to have it run at set times.
For the greenhouse I've setup foggers at the top of the greenhouse and use a Rachio controller with the Cycle and Soak setting turned on which gives me a nice mist every 15 minutes during the hot part of the day and every 20 minutes during the warm parts of the day.
With the fans running and the foggers going I can, even on hot days like today, keep the plants about 3-8 degrees cooler (see screen shot above). Current temperature is 96 degrees, but the greenhouse is 89 degrees currently. Our typical summer day is about 91 degrees here and on average the greenhouse is around 88 degrees during the hot part of the day. Which means less stress on the plant, little to no leaf burn and possibly more growth.
I'm using Jain foggers. Fairly easy to setup and they put out a very fine mist with very little dripping after they shut off. Like the name implies, it looks like a fog when there is no wind and if you run them long enough.