1 Chandos Street, St Leonards


Lifecycle replacement of an original boiler. Design, supply & Install new energy efficient condensing boiler

The existing gas fired boiler (410kW) is original to the building and serves the buildings Heating Hot Water (HHW) system which consists of a hot water reticulation loop running through the building to numerous hot water heating coils located within various air duct ducts on each separate level of the building. The domestic hot water system utilises a calorifier located at roof level, which is a storage tank with an internal heating coil connected to the main heating hot water boiler. The calorifier system was replaced with an independent domestic hot water service splitting the mechanical heating from the domestic heating. Even when there is no space heating requirement, the main building boiler runs to provide heating to the calorifier. This is extremely inefficient.

For the boiler upgrade two different options have been investigated; a modulating condensing boiler and a non-condensing boiler. The difference between the two is that a condensing boiler allows for lower return inlet water temperatures (35°C) compared with a non-condensing (50°C). The condensing boiler also has a higher operational efficiency (90%) compared with the non-condensing (83%). The footprints of each unit are similar and can spatially fit within the room. However following due diligence into each boiler type, it was found that due to the limited access requirements to the plant room, such as one doorway and a narrow staircase leading up from level 10, a modular condensing boiler would be more favourable due to its compact size and ease of disassembly and reassembly on-site. Two different models of condensing boiler were investigated further and the merits of each type are shown in the table below.

The original boiler was replaced with a 300kw condensing boiler which is 30% more energy efficient than the existing 400kw gas fired boiler


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