angled atmospheric-humidity botanical-gardens cloud-forest conservatory conservatory-complex controlled- temperature cool-moist cooling curved curves curving dome domes energy-efficient environment flowers gardens glass glasshouse greenhouse heating high high-tech horticultural horticulture hothouse indoor-gardens light lighting mountain optimized-conditions plants regulated-climatic-conditions Singapore steel structure sustainable-building-technologies tall tallest transparent unique ventilation visibility warm-growing-environment water waterfalls windows billies billy conserved-heat container convenient cooking-device durability durable economical efficient fuel-minimises fuel-minimizes handles heat-loss-minimised heat-loss-minimized heat-retention ice-cooler inner-pots insulated insulation keeps-flavour less-evaporation lids non-electric pan picnics portable portable-oven pot pots retained-heat retains-nutrients rice-cooker safe safer sauce-pan slow-cooker spill-proof stainless-steel strong thermal-cooker thermal-cooking thermal-insulation thermos-vacuum travel vacuum-cooker vacuum-flask water-saver zero-energy-use