Before we build a greenhouse, we have to understand the critical issue of a conventional greenhouse.
The cirtial issue with any other greenhouses is, too bloody HOT during day/summer and too COLD during night/winter. That is, polarization between two extremes is the issue. If you do not know what we are talking about here, then you do not have a handson experience of this.
How do you solve this problem?
Nothing can solve this problem until you STORE the thermal energy collected during the day and then INSULATE the greenhouse to such an extent that you keep the heat inside and prevent the low temperature radiant heat from seeping in. As a rule of thumb, the insulation has to be so good that the inside temperature drop/loss during the night has to be kept below 1 degree per hour (16 hours between 5pm and 9am in winter means 16 degrees drop). Period. Not doing this with soap liquid bubbles is a pure waste of solar energy and your money.
Remember, WATER is the BEST heat battery/capacitor on earth. Not utilizing this wonderful property of water is purely unwise. The wonder of soap liquid bubbles is, they mix air with water to create a thermal mass that is light in weight and better for solar thermal capture. And it does not block the light coming in, it simply scatters the light and give your appearance of whiteness.
