An energy conservation design in vacuum sanitation systems

Vacuum sanitation systems are environmental friendly and are widely used in new residential equipment and passenger transport. The water consumption is reduced in such systems but a large amount of energy is required to generate the vacuum. In respect that designers of current systems did not consider the difference in energy supply to collect different amount of waste, these systems are less practical than desired and can be improved upon for energy conservation. This paper proposes a variable vacuum-degree sanitation design that is more energy conserving than the currently used vacuum sanitation devices. The vacuum degree is chosen automatically due to the amount of solid and liquid waste. In the case of less waste, smaller vacuum degree is generated, resulting in energy conservation. The closestool of this new device is specially designed to have the ability of testing the amount of excrement. The vacuum degree is then adjusted by controlling the compressed-air supply according to the dynamic pressure response of pneumatic ejector circuit. To verify the effect of energy conservation, experiments are carried out in the artificial excrement collection, and the variable vacuum-degree design saves more than 50% of the energy supply.