Difference between revisions of "SPIS Toolbox - Estimate System Size and Costs"
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Following this procedure, the principal analytical steps to support decision-making should be completed. The technical, agronomical and financial aspects of the possible SPIS configuration (and alternatives) should now be available. | Following this procedure, the principal analytical steps to support decision-making should be completed. The technical, agronomical and financial aspects of the possible SPIS configuration (and alternatives) should now be available. | ||
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*Required PV generator size; | *Required PV generator size; | ||
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*Suitability check list / evaluation. | *Suitability check list / evaluation. | ||
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== Data Requirements == | == Data Requirements == | ||
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*Country-specific costs of PV pump [Currency/kWp]. | *Country-specific costs of PV pump [Currency/kWp]. | ||
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== People / Stakeholders == | == People / Stakeholders == | ||
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*Experienced system integrators. | *Experienced system integrators. | ||
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== Important issues == | == Important issues == | ||
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*A commercial software solution that integrates design for the PV pump and the irrigation system is currently not available on the market. | *A commercial software solution that integrates design for the PV pump and the irrigation system is currently not available on the market. | ||
*SPIS usually have to be oversized to meet these peak demands, resulting in a fairly low degree of system utilization. | *SPIS usually have to be oversized to meet these peak demands, resulting in a fairly low degree of system utilization. | ||
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[[Category:Tools]] | [[Category:Tools]] | ||
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Revision as of 13:45, 12 May 2017
Estimate System Size and Costs
Proper sizing of the components of an SPIS is critical,since an SPIS with insufficient capacity will not satisfy the farmers’ needs and an over dimensioned system will induce unnecessary operation and capital costs. Negligence of the sustainable water yield of water sources may result in water shortage and a depletion of water resources, thus having negative impacts on the farm budget and the environment.
The required size of the PV generator can be estimated using the following parameters:
- daily crop water requirement Vd [m3/day]
- total pumping head HT [m]
- mean daily global solar radiation G for the design month [kWh/m2day].
A simple arithmetic formula that takes the individual system component efficiencies into account can be used to estimate the required solar-generating peak power
P peak [Wp].
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Example: It is calculated that crops in an irrigation system require 30 m³/d and field observations confirm that water needs to be pumped up 50 meters from a borehole to a reservoir. From the NASA website it becomes clear that the daily total global irradiation at the location of the farm is 5 kWh/m²day. According to this equation, a 2.4-kWp PV generator is required. |
The DESIGN 03-Pump Sizing Tool (Excel-based worksheet) can be used to select the typeof solar pump. The tool includes a database of 100 solar pumps available on the market toallow for a pre-selection of the motor/pump unitby the agricultural advisor.
The approximate cost of theplanned PV system can be calculated by multiplying the country-specific average system cost [currency/kWp] and the calculated PV generator power (P peak).
The final design of the PV pumpand irrigation system should be left to experienced system integrators who use computer-based system sizing and simulation tools such as COMPASS, WinCAPS and PVSYST, HydroCALC, GESTAR (See Further Reading, Links and Tools at the end of the Module).
An example of the design of a simple SPIS is part of the toolDESIGN 04-Case Study Mr Paolo.
Following this procedure, the principal analytical steps to support decision-making should be completed. The technical, agronomical and financial aspects of the possible SPIS configuration (and alternatives) should now be available.
Outcome / Product
- Required PV generator size;
- Pre-selection of motor/pump unit;
- Motor/pump characteristics;
- Layout of water distribution system;
- Daily course of solar irradiation and water flow;
- System cost estimate;
- System cost parameters;
- Suitability check list / evaluation.
Data Requirements
- Daily crop water requirement Vd [m³/day];
- Total pumping head Ht [m];
- Mean daily global solar radiation G for the design month [kWh/m²day];
- Country-specific costs of PV pump [Currency/kWp].
People / Stakeholders
- Agricultural service providers;
- Experienced system integrators.
Important issues
- A commercial software solution that integrates design for the PV pump and the irrigation system is currently not available on the market.
- SPIS usually have to be oversized to meet these peak demands, resulting in a fairly low degree of system utilization.
