Pumps UK were contacted by CITI bank in Canary Wharf to advise on an upgrade on their cold water booster set. The current insulation had 4 x directly driven long coupled pumps, each pump had 90 KW motors on them. The pumps had been designed to run as Duty Assist but because the 40 bar draw down vessel had been removed 2 pumps were starting at once and running on without any demand.
The equipment was also of high importance; not only did it supply all the water services to one of the biggest banks in Canary Wharf, it supplied the water to the cooling towers that kept the data centres cool.
We carried out a survey on the water demand on the system and found that we could reduce the size of the pumps and greatly reduce the motor size. This would result in a saving of over 90kw per hour. This making a 12 month “payback” time for the works.
The new pumps also were fitted with Inverter so that we could keep a constant pressure in the system, and the pumps would cascade duty as the flow rate increased in the system. This would also greatly reduce the energy required for the system.
We decided that we would remove all the pumps and controls and start again. We selected four Lowara e-SV vertical multistage pumps that had the capability of producing 40 Bar of head. Due to the importance of the equipment we had to carry out the works over various weekends.
As the set could not be switched off, we had to remove one pump at a time. Due to the size of the new pumps, we had to split the motors and pump bodies in half and then re-build them in position. To avoid all the existing pumps and pipework, we had to build a frame and lifting points in and around the existing equipment.
The suction pipework from the new pump was also built and installed on site. This pipework was only suppling the water from the break tank which was located in the other room opposite to the pumps, so this did not have a great amount of pressure behind it.
The discharge pipe had to be fabricated from steel pipe as the pumps were pumping up 48 floors and generating around 40bar of pressure. To ensure there was no issue with the new discharge pipes, on the day of installation we carried out hydrostatic test before attended site. Also as these pumps where supply drinking water we had the pipework dipped in a galvanised solution to remove the risk of contamination.
We also fitted a pressure vessel at the top of the riser to act as a buffer vessel so that the inverter could over ramp and stop the pumps at low demand. This also meant that the vessel could be rated at 16 Bar.
This system has now been running for some time and has saved the client a substantial amount of energy and consequently, a lot of money.
If you would like us to attend your site to see if this is possible in your building, please feel free to contact our team to see if we can offer a solution.