Abstract outline

Water supply systems are built to supply needed water. These systems often consume power from pumping the water from a low elevation to a reservoir high above. This reservoir is used for a buffer between periods of peak demand. In order to create stability, these systems often require pressure reduction on the way back down to the delivery point. At this reduction location, energy is dissipated into heat from the large spring within the pressure reducing valve, resulting in wasted energy (see Figure 1). Has energy recovery in these water systems been ignored when building them in the past, and can electric power be generated by replacing existing pressure reducing valves with a specially designed Power Generating Pressure Reducing System (PGPRS) (see Figure 2 and 3)?

To reduce this energy consumption a number of reverse running centrifugal pumps will be used as turbines in a PGPRS; this will help recover energy from the water system without disrupting the intended use. The PGPRS will be a system incorporating an in-line design that will use a set of parallel reverse running pumps along with a smaller pressure reducing valve. With this set of components in line with the water main, a series of computer controlled switches and valves will allow the turbines to be enabled or disabled as the flow demand increases or decreases. This will result in the required pressure reduction, as well as a stable AC power source that can be directly distributed to a grid. The pump manufacturer’s data will be used to determine a practical design on a pipe line at Highland Valley Copper (HVC). Also, satellite surface imagery of the identified water main at HVC will be used and compared with the actual pipe line survey. From that model and the strategy used to create the design, a method will be created to inform technologists how to locate, size, and design the PGPRS particular to their identified water system.

A method of determining appropriate water supply systems and adaptation, as well as the feasibility of this technology will be explored, reported and documented. It is expected that this technology can be adapted to many existing water supply systems, and that the cost of the conversion could be offset by the production of clean energy.

Water Supply Systems
What are the common types of gravity fed water supply systems that require pressure reduction and where are they located?

• Potable water supply
City/municipality

• Irrigation
City/municipality, Farming,

• Industrial water supply
Mining, pulp and paper

• Waste water
Sanitary/ storm sewer/

• Potable water supply
City/municipality

Pressure reducing and Pumps As Turbines (PAT)

How do break pressure tanks work?
• Returns excess pressure within a pipe line to atmospheric pressure before transferring it on.

Where are they used?

Can a PAT be installed up stream of this type of pressure reduction?
• this seems like it could be comparable to conventional power production where the output flow is released into atmospheric pressure
How do pressure reducing valves work?
• Spring loaded valve that opens with respect to the pressure loss to the downstream pressure setting

Where are they used?

Can a PAT be installed up stream of this type of pressure reduction?
Yes it can!!!!
What is the relationship between pressure loss, flow rate, and power production?

What kind of pressure reduction is created from a PAT?

Can the input and output pressure be compared to that of a PRV?

Is there technical information on a PAT that a pump supplier can supply in-order to design a system that can be placed up stream of an identified pressure reduction location?
Pump curve data is convert to turbine performance

Who are the main manufactures of PAT?

Is PAT being applied to existing water supply systems within BC?
Yes it is!!!!!
Viability
What makes this technology viable?
Grid connection or stand alone power supply effects economic viability because to pay back on a grid connection one must rely on commodity value which can be quite low for small hydro producers.
stand alone can be viable because it is supplying the needed power not trying to sell it.
Flow variation will effect the turbines ability to produce power, in a multiple turbine application some turbines will not produce when flow is not at full capacity resulting a turbine or two not being payed for.

a single flow rate will ensure turbine performance 24/7

government polices, taxes, and lack of engagement to support small hydro may be causing this energy recovery technology to be delayed and not implemented due to costs becoming too high to be economically viable.


turbines need to be turning all times at good efficient levels in order to be viable
What is the life expectancy of the PAT components?