The NEED for Flow

Living in densely populated Hong Kong, residential buildings are in high demand, comprising 7% of the city's land area. Our team of innovators noticed the constant illumination in apartment complexes, prompting us to explore greener solutions. While leaving lights on may seem wasteful, it ensures safety for residents with varied schedules and emergency situations. However, this practice consumes significant energy, mainly generated from non-renewable sources like coal and natural gas, contributing to carbon emissions and climate change. To achieve Hong Kong's emission reduction goals, a shift to renewable energy is crucial. Moreover, powering lights 24/7 is financially burdensome for property companies due to rising electricity tariffs.

To address these challenges, I propose FLOW, a generator that captures energy from wastewater. By installing these generators in residents' homes, we can power a portion of the complex's lights using the energy generated from shower water. This solution is environmentally friendly, utilizing clean energy sources, and is financially viable, offering long-term cost savings.

Concept Details

The energy production of this generator is based on the conversion of energy from mechanical energy (KE + GPE) to electrical energy. As energy is conserved in this closed-system generator, it will alter the conversion between the gravitational potential energy (the energy that withstands the generator) and the kinetic energy, which stands for the water movement. Due to the small size of the generator components, the gravitational potential energy and frictional energy that is dissipated from the generator will be reduced, making this a high-efficiency generator. There are two modules where the main calculations will be performed, the first module is where the water will come in contact with the generator turbine (water source and pump), and the second module is the top of the elbow joint pipe, where it will supply water to the shower sectors in bathrooms in the households. The pipes all take place in the residential pipe room, which has a connection to the power supply and switch room in the household.

Dimension of the Magnet
6 cm × 2 cm × 2 cm

Diameter of the Coil
4.5 cm

Cross-Sectional Area
15.9 cm^2

Hong Kong street lamps were gradually replaced by sodium lamps with energy-efficient light-emitting diode (LED) systems in 2016. This also gradually affected the majority of residential zones. Each lighting source for 7m LED Street Lamps has a power of 30W and is usually in operation from dusk to dawn, detected by the light sensors. This gives the flexibility of the street lamps to turn on and off at different times, which gives the opportunity for extra energy to be conserved due to its effective usage.

Typically, the duration of dusk till dawn in Hong Kong is 8 hours and 30 minutes in summer and 10 hours in winter. This gives the energy consumption of a 7m LED Street Lamp in summer to be 0.255kWh and 0.3kWh in winter every night. Dividing the total energy production of all generators from each apartment by the energy consumption of one streetlight gives the values 10.8 and 9.18, respectively. Hence, each apartment can power up to 9 to 10 street lights every night. This exceeds our expectations, as there are only 40 street lights in the entire 10-apartment community. the extra electrical power will remain stored in the thermal energy storages that are implemented in the underground of each apartment.

FLOW’s Technology

The FLOW generator incorporates three main technologies: the waterwheel, V-Belt drive, and a piston structure connected to a coil of wire. The waterwheel captures the movement of water, inspired by traditional designs but with curved blades for increased efficiency. The V-Belt drive connects two wheels of different sizes with a belt, enabling variable speed and power transmission. The piston converts high rotary speed into horizontal movement for the wire coil.

Compared to other renewable energy solutions in Hong Kong, such as hydropower plants, FLOW is more feasible and efficient. The scarcity of water sources and limited land availability make large hydropower plants impractical. In contrast, FLOW's small size allows for installation in individual apartments, generating enough energy to power complex lights. A collective installation of FLOW generators in an apartment complex can generate up to 27.54kWh per day, equivalent to powering 90 LED lights. No additional land excavation is required, making it a convenient and effective solution for community needs.

FLOW

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Compliant Dispenser Pump

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Street Light Control Circuit - Non-Inverting Schmitt Trigger