Refrigeration and refrigerating machinery Air conditioning 42 Heating 25 Congresses 12 Handbooks, manuals, etc 12 Cold storage 11 Ventilation 10 Heat engineering 6 Equipment and supplies 5 Periodicals 5 Food 4 Buildings 3 Cooling 3 Energy conservation 3 Environmental engineering 3 Frozen foods 3 Ice 3 Manufacture 3 Transportation 3 Ammonia 2 Automatic control 2 Building materials 2 Environmental aspects 2 Farm produce 2 Fruit 2 Heat 2 Low temperature engineering 2 Low temperatures 2 Maintenance and repair 2 Refrigerants 2