Public procurement notice: Periodic Indicative Notice Without Call For Competition
Published: 2017-02-08
Buyer: Transport for London — London Underground (Line Upgrades)
Country: UK
Contract type: Services
CPV classification: 42500000 | 42510000 | 42511100 | 42512000 | 42512200

Technical requirements: London Underground is inviting companies to participate in market engagement for the Platform Air Handling Unit (PAHU) Development project. This project is being undertaken by Power and Cooling upgrades to provide cooling in support of the Deep Tube Upgrade Programme (DTUP).
A PAHU is a bespoke device which provides cooling to the platforms at London Underground stations. The unit comprises a fan and cooling coil in an enclosed unit and cooling is provided by connection to a chilled water system.
PAHUs were installed at two high-use LUL stations in 2012 but have been found to lose operational functionality over time because the cooling coils are subject to fouling due to their fin pitch spacing, depth and configuration. Furthermore, due to the location of the units on the crown of the tunnel above the track, access to clean and maintain the units is limited due to the constraints of engineering hours and height they are installed at. This has lead to a very high operating cost in terms of frequent and labour intensive maintenance works.
LUL have undertaken a trial in a station environment which has developed a new cooling coil configuration which is capable of maintaining functionality for a longer period. The results of this trial have been used to develop a feasibility study into the installation of the PAHUs in different form factors/locations on the platform and more a modular design to improve maintenance and installation.
The project only covers the ‘primary’ system of the PAHU, which is the interaction between the chilled water in the coils and the air. It is worth noting that there is significant work to be done on the relationships between flow rate, chilled water temperature, condensate production and refrigerant medium in the ‘secondary’ system that is currently outside of the scope of this project.
The high-level objective of the PAHU Redevelopment project is to take the output of the trial and feasibility study and to undertake further design development and ultimately a trial in a high-demand LUL station. The key stages of the project are as follows:
— Concept Design: design of three units of different form factors/locations on the platform, building on the output of the feasibility study.
— Trial: manufacture of one design and a trial in an LUL station in Summer 2018 (note, the enabling works and installation would be undertaken by others).
It is expected that successful design and trial of a new PAHU design will lead to a substantial roll-out of units across a number of locations over a 10-20year period.
— Cooling unit shall be designed to achieve a nominal 30 year life, assuming proper maintenance and a mid-life refurbishment.
— The unit shall be able to operate for a full summer season (May — September) without normal maintenance intervention e.g. cleaning.
— The unit design shall not exceed a size or weight that can be installed (or removed) on the infrastructure via normal accepted access and delivery arrangements, i.e. without the need to use an Engineering Train.
— *Designer can review increasing the ΔT in order to maximise the cooling performance of the unit (kW/m2 of coil area) but any alterations need to be cognisant of the impact of this change on the chiller size, volume of condensation and hence operational costs.
— The system shall be capable of providing a design capacity of not less than 200 kW of cooling per platform in a clean state. Where practicable, the cooling performance will be maximised above this value to a maximum value of 300kW.
— At any point in the year the cooling performance when normalised to the design conditions shall not fall to less than 85 % of the rated performance at the design conditions.