The predominant wind direction is from the South-West which means that air is blown over the river and the water meadow provided as part of the landscape in front of the building. There is some degree of evaporative cooling which reduces the air-temperature of the incoming air. Exposed concrete soffits provide the majority of the thermal mass and these are pre-cooled by the night-time cooling strategy. In very hot weather when the natural ventilation can no longer maintain the required conditions, cool water (fed by the river cooling system) is circulated around either chilled beams or pipes embedded in the concrete slab to provide further cooling. The building was designed to make maximum use of daylight, both to provide a bright environment and also to reduce energy consumption. The large window areas and 'sky-lights' in the roof cones provide sufficient natural light for low-energy electric lighting to be kept to a minimum, reducing both energy demands and ambient heat creation. Artificial lighting typically represents around 30% of a building’s energy use. The required quietness levels needed in The Hive's extensive study areas are achieved through vertical decorative Ash 'fins' mounted on sound absorption blankets fixed to the structure's concrete soffits, and acoustic panels positioned strategically all around the building. The main heating source in winter is a 550 kW biomass boiler, with emergency back-up being provided by three 250 kW gas-fired boilers. In extreme summer conditions, river water is pumped into the basement of the building, passed across concrete heat exchangers, with the cooled air ducted up into the central atrium. Temperature checks are maintained on the water returned to the river to comply with the UK Environment Agency's fish protection regulations. The engineers developed a strategy which uses the River Severn as a heat sink. Water is pumped from the river to The Hive, passed through a heat exchanger and then returned to the river at only a few degrees warmer. On the other side of the heat exchanger, water is pumped around the building and used to cool the concrete slabs; the water inside the building is kept hydraulically separate from the river water to prevent contamination and blockages. Rainwater harvesting is used to serve the WC flushing and archaeological washing requirements. Neither of these require potable water and so can be fed from harvested rainwater with minimal treatment. They also represent the greatest consumptive use within the facility. Landscaping consultants Grant Associates surrounded the library with plantings of Black Pear (the county fruit of Worcestershire), black poplars, cherries, oaks, pollarded willows and medieval fruits.