Efficiency improvement of Spanish irrigation project

Dur­ing the dry sum­mer sea­son, the increase of the vol­ume of water avail­able to an irri­ga­tion chan­nel in North­east Spain has ben­e­fit­ted local agri­cul­ture. With exten­sive sup­port from Sulz­er, the reser­voir of San Sal­vador has been suc­cess­ful­ly com­mis­sioned with ener­gy con­sump­tion kept to a minimum.
Main­tain­ing an effec­tive agri­cul­ture sys­tem is essen­tial to keep­ing food on the super­mar­ket shelves and this requires an effi­cient and reli­able sup­ply of water. As the demand for this resource increas­es, so it becomes more impor­tant to opti­mize the stor­age and deliv­ery of fresh water supplies.
From the out­set, the project own­ers were very clear that oper­a­tional effi­cien­cy was the top pri­or­i­ty to ensure that annu­al run­ning costs were kept to a min­i­mum. The com­pa­ny Sulz­er design and engi­neer­ing entered the com­pet­i­tive ten­der with a pro­pos­al that would lat­er be shown to offer between 15% and 50% improve­ment, depend­ing on the con­di­tions, on the run­ning costs of a rival bid. This ben­e­fit, while appeal­ing, was sup­ple­ment­ed by the pro­pos­al from Sulz­er to work in part­ner­ship with the cus­tomer and offer its con­sid­er­able exper­tise in pump­ing solutions.
Rather than just deliv­er­ing a num­ber of pumps that could deliv­er the nec­es­sary water flows, Sulz­er pre­pared a com­pre­hen­sive solu­tion that includ­ed all the con­trol infra­struc­ture as well as all the main­te­nance equip­ment. In fact, the design of the final instal­la­tion would involve siphon-effect dis­charge pipework that would improve the per­for­mance of the pumps by reduc­ing the sta­t­ic head. For this project, the com­pa­ny pro­posed some of its lat­est pumps equipped with pre­mi­um effi­cien­cy, IE3, PE7 motors that would make an excel­lent start­ing point for an ener­gy effi­cient installation.
The cus­tomer was look­ing for a part­ner to help with the design of the pump­ing sys­tem as well as the infra­struc­ture for remov­ing and installing the pumps for main­te­nance. This need­ed care­ful con­sid­er­a­tion to ensure safe han­dling of the pumps. Addi­tion­al­ly, all the lift­ing equip­ment and pro­ce­dures had to be approved by an inde­pen­dent assessor.
The cir­cu­lar shape of the pump­ing sta­tion build­ing posed many chal­lenges for the design­ers, not least the lack of space for all the equip­ment. Sulz­er sug­gest­ed the instal­la­tion of one pump con­trol cen­ter to oper­ate two sets of pumps. This pro­pos­al was accept­ed, sav­ing both space and expense for the project. The pump­ing sta­tion had to be built in two inde­pen­dent­ly oper­at­ed sec­tions, allow­ing pump main­te­nance to be car­ried out with­out affect­ing capacity.
Each set of four pumps is made-up of two dif­fer­ent pump mod­els, cho­sen by the engi­neers to offer the most effi­cient pump­ing solu­tion for every lev­el of water in the reser­voir. The pumps are con­trolled by vari­able speed dri­ves and this com­bi­na­tion allowed Sulz­er to cre­ate a chart that showed how dif­fer­ent com­bi­na­tions and set­tings of the pump con­trol sys­tem would oper­ate depend­ing on the water lev­els in the reservoir.
The pump­ing sta­tion is designed to main­tain a suf­fi­cient water lev­el in the dis­tri­b­u­tion chan­nel so that the irri­ga­tion sys­tem remains oper­a­tional. How­ev­er, the water lev­els in the reser­voir can change sub­stan­tial­ly, espe­cial­ly between the dry and rainy sea­sons. Estab­lish­ing the best pump arrange­ment and pump­ing regimes would pose a con­sid­er­able challenge.
The pumps are installed over two lev­els as well as being split into two inde­pen­dent sec­tions. Each pump was designed with its own siphon effect sys­tem at the dis­charge point that would deliv­er con­sid­er­able ener­gy sav­ings over the whole ser­vice life of the pump. This was a very impor­tant con­sid­er­a­tion for the cus­tomer, and one that would be piv­otal in Sulz­er win­ning the contract.
In instal­la­tions where large elec­tric motors are oper­at­ing round-the-clock, small improve­ments in effi­cien­cy can make a sig­nif­i­cant dif­fer­ence in ener­gy costs. When this is com­bined with opti­mized valve designs, the addi­tion of the siphon effect and pre­ci­sion con­trol, the over­all effi­cien­cy is magnified.