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UNICEF Ethiopia

awashtenders.com Sep22,2020

Clarification 1- for LITB-2020-9160928 Procurement of Solar water pumping system

In addition to the below clarification on specifications, due date for submission is extended until 30.09.2020 at 2:00PM

Clarification for the question raised by KG international Enterprise

1.      It is believed that the proposed “Sun switch” is required to prevent the pump from overheating. If your pump controller has equivalent function, it is well. But, other bidders did not raise this question and may supply the “Sun switch” besides the pump controller. So, for bid evaluation purpose, you should supply the “Sun switch”.

2.      Since the production casing diameter of Ashuda bore hole is 8 inch, the 6 inch pump will safely enter the well. So, it is acceptable if your enterprise supplies 6 inch diameter pump.

3.      Similarly in Robit water supply project, a 6 inch diameter pump is acceptable for 8 inch casing diameter.  Since, the safe yield of the bore hole (17 l/s) is more than the recommended pump discharge (5 l/s), keeping the specified head installing 22KW pump may increase the discharge by some percent. Since, the borehole yield is enough to accommodate the discharge variation, it may have no negative impact on the system. So, we prefer a better pump power and your recommended 18.5KW pump is not acceptable. 

4.      Regarding Barwa water supply project,currently the project is providing the service for the community and the existing electrical submersible pump installed in the collection chamber is a horizontal pump. So, the main objective of installing the solar pump for this project is to reduce the cost of fuel, maintenance and operation cost.Since, the depth of the collection chamber is small (3m), vertical submersible pump is not acceptable.

5.      The coordinates of collection chamber and the service reservoir of Barwa water supply project are:

Description

Collection Chamber

100m3 Service Reservoir

Easting

440200.84 m    (38.45OE)

442552.49 m      (38.47 OE)

Northing

1409693.80 m  (12.75ON)

1410632.82 m     (12.76 ON)

Elevation

1195.3 meter AMSL

1140.14 meter AMSL

 The maximum input voltage of the inverter is 750V. It is a typing error which says 75V.

 NB:For bid evaluation purpose, we advise the bidders shall supply the materials as per specifications stated in the bedding document.

Clarification for the question raised by DAVIS & SHIRTLIFF

1.      Pump Power (KW):

For Robit and Barwa water supply project, you can deliver the solar pumps at the higher side of the specified pump power. For Ashuda water supply project if the pump attains the specified discharge and head(duty point) and the efficiency is >=70% at peak solar intensity time, a lesser power pump is acceptable.However, a higher power pump (higher discharge) will deplete quickly the water in the borehole and affect the borehole life. So, it is not acceptable to supply a higher power pump for Ashuda Project.

Solar Panel Size:

Your enterprise can offer solar panel size above the specified power in the bidding document. But, the pump controller voltage and other accessories required for the installation of should suit the solar panel power.

Solar Panel Quantity:

The quantity of solar panel to be supplied should satisfy the required solar pump power specified on the bidding document.But, installation drawing should be attached with the bid document to check the required power, maximum voltage and current specified in the BOQ.

2.      The required data for source coordinate, length, type and diameter of pressure line for the three water supply projects, and dynamic water level of Ashuda water supply project are attached in the table below

Transport and Installation Cost: as communicated earlier, the RWB prefers supply of solar water pump under this bid, installation can be undertaken locally.

Basic Data concerning Ashuda, Barwa and Robit  Water supply Project

Item No

Description

Unit

Ashuda

Barwa

Robit

 
 

1

Source co-ordinate

 

 

 

 

 

 

Easting

m

269795.84  (36.89 OE)

442552.49  (38.47 OE)

379452.09  (37.89 OE)

 

Northing

m

1265472.16 (11.44 ON)

1410632.82 (12.76 ON)

1397580.77 (12.64 ON)

 

Elevation

m

2040.24

1195.3

1714.21

 

2

Service Reservoir

 

 

 

 

 
 

Easting

m

 

440200.84 (38.45 OE)

379571.61 (37.89 OE)

 
 

Northing

m

 

1409693.8 (12.75 ON)

1397398.7  (12.64 ON)

 

 

Elevation

m

2110.42

1340.14

1818.42

 

3

Pressure Main

 

 

 

 

 

3.1

Length

m

1701

3295

1176.22

 

3.2

Diameter

mm

DN 65

DN 80

OD 90

 

3.3

Type

 

GI

GS

HDPE

 

4

Riser Pipe

 

 

 

 

 

4.1

Length

m

98

Horizontal Surface pump will be installed at 25 m3 circular collection chamber (Internal diameter=4m and Depth=3m)

110

 

4.2

Diameter

mm

DN 65

2  1/2”

 

4.3

Type

 

GI

GI

 

5

Dynamic water level

m

90

90.30

 

Clarification for the question raised by LG Patsons Engineering Pvt. Ltd.

   Clarification for commercial Queries of question 1-3 shall be given by UNICEF Procurement Section.

Technical  Queries

1.      For Robit and Barwa water supply project, your enterprise can offer the solar pumps at the higher side of the specified pump (10-15% of the specified discharge) considering the fluctuation of the solar intensity. However, for Ashuda water supply project the recommended pump discharge is almost equal to the yield of the bore hole. So, a higher discharge pump will deplete quickly the water in the borehole during the peak intensity hour and may seriously affect the borehole life. So, it is not acceptable to supply a higher discharge pump for Ashuda Project

2.      The ‘Best Point’(ηmax) efficiency of the pump should be >=70% during the peak intensity period. However, for evaluation purpose, your enterprise shall offer the best efficient pump as much as possible.