Solar Thermal Market By Collector Type (Evacuated Tube Collector, Flat Plate Collector, Unglazed Water Collector, Air Collector), By System (Thermosiphon Solar Heating System, Pumped Solar Heating System), By Application (Hot Water Systems, Solar Combi Systems, Swimming Pool Heating, Others), By End Use (Residential, Commercial, Industrial): Global Opportunity Analysis and Industry Forecast, 2021-2031