EFFICIENCY

Turbine Types:

When talking about efficiency it's important to understand that there are many different types of turbines which all have unique use cases. To the left you can see a graph containing common turbine designs and a rough estimate of their power output at different flow rates and effective heads. For my purposes I used a Francis turbine because it's easily the most adaptable in terms of its versatility to power output. It is important to note that in a purely low-head situation turbines like the Kaplan would better fit the job, however, a Francis turbine will still work while also providing a better understanding of hydroelectric principals. 

Head:

The basic definition of head is how far the inlet of the turbine is from the surface of the water above the dam. When talking about head we use two distinctions, hydraulic head and effective head. Hydraulic head refers to the total distance between the water's surface and turbine’s inlet like stated before. Effective head or net head considers the losses due to friction that the water experiences as it travels down the pipes to the inlet of the turbine, so in order to calculate your effective head you subtract your losses from friction from your hydraulic head.

Flow:

Flow is measured in either cubic feet per second (CFS) or Cubic meters per second. How Much flow a turbine can intake per second is primarily a result of the inlet diameter, water velocity at the inlet and its outlet diameter. In order to maintain high efficiency in a turbine these 3 factors must be balanced. It can be hard to imagine what a cubic foot or cubic meter of water actually looks like. There are two ways of thinking about it, mathematically or visually. Mathematically a cubic foot of water is 62.4 pounds and a cubic meter of water is 1000 kilograms, while it is easy to understand the force behind the water with this method it's difficult to understand the volume. Visually you can think of a cubic foot of water being about 1 adult chicken and 1 cubic meter of water being 35 chickens, while silly this does allow for an understanding of how much water passes through a turbine each second.   

Watts:

A watt is simply a unit of power and is the product of Volts * Amperage. Many household appliances are measured in watts or some form of watt hour. When generating power, watts are measured in kilowatts or megawatts because it's on such a large scale. 1 kilowatt is 1000 watts and 1 megawatt is 1000000 watts. A kilowatt hour is a common form of measurement especially for a household, for example if a 100-watt light bulb that runs for 10 hours will1 kWh of energy.

Calculator:

Use this to calculate the power a hydroelectric turbine in a low-head dam scenario would produce.

(this calculator assumes a Francis turbine configuration)