Sustainability Series – Dockline

Sustainability Series – Dockline

Design, Sustainability, Work

Dockline – Successful refurbishment with significantly improved energy rating and lettable space – plus LEED Platinum certification

This recently completed project was a refurbishment of the existing New Century House in Dublin’s IFSC- now renamed to Dockline. The building was originally constructed around 1998 and surrounded by residential and commercial developments on all sides. The LUAS line runs adjacent to the north of the building, restricting construction works and access to site.

The building consists of six levels of lettable tenant office space and a basement including parking and amenity spaces. The works included the strip-out of all existing plant and refurbishment of the façade. There was a significant sustainable energy drive for the development. This resulted in the existing natural gas supply providing space and domestic water heating being removed and replaced with heat pumps.

A mix of Shell & Core and Cat A on tenant floors was delivered, with full fit-out of landlord and front-of-house areas including reception, amenities and toilet cores. Part of the project scope also included the installation of new lifts in the building.

Improved energy rating and how we achieved it

The project included upgrading the overall building from a D2 BER rating to an A3 BER rating. This facilitated the building achieving certification of LEED Platinum. The resultant energy emissions from the development were:
• Building Energy Emissions: 80.2 kWh/m²/yr
• Carbon Dioxide (CO2): 15.77 kgCO2 /m²/yr

Various options were considered during an iterative design process to improve the envelope in conjunction with the most efficient plant given the restricted use of space. Within the design energy model, variations of improved façade, i.e., U-value options with insulated suspended slab and roof options were run against efficiencies of heat pumps available on the market. Costings against these options were negotiated with the client and project team to ensure the most viable market solution was achieved with sufficient payback for client. The energy model also took into consideration the daylight and overheating analysis on each floorplate given the full height glazing, with the associated g values.

Improving lettable space

To enhance and improve the lettable space, existing mechanical ventilation plant, which was previously located locally at each floorplate, was removed to give more nett lettable space, with plant relocated to the basement carpark. The existing air-cooled chillers were located at roof level, this too was replaced with high efficiency heat pumps and relocated to the basement, with the space infilled to give more lettable tenant space.
Based on the location of the development near several public transport links, reduced car parking over increased lettable space was favoured.

Sustainable design features

As part of the electrical design works, LED lighting was installed throughout replacing older fluorescents. PIR occupancy sensors were incorporated in open plan areas, to minimise energy use. A lighting control system was installed to monitor and allow easier control of the systems.

Energy consumption monitoring
Energy metering was installed on each floor distribution board, as part of the overall LEED strategy. This allows for monitoring of the overall usage through the central BMS system. Power factor correction was installed within the main switch room to further limit energy wastage.

EV chargers
As part of the planning application and LEED accreditation the addition of EV chargers was included in the design, adding to LEED credits.

Water consumption management and monitoring
Water meters have been added to each tenant floor plate. These are linked back to the central BMS. They notify if high levels of water are being used, which may be caused by leaks in the system. Individual cleaners’ sinks are provided with separate meters, in line with LEED credits. Booster pumps have incorporated variable speed drives. All sanitaryware including WHBs, showers and toilets are low flow/flush, with taps being sensor-operated.

Heating and cooling
The high-efficiency 4-pipe heat pumps provide heating and cooling to tenant and landlord spaces, and all tenant spaces are provided with energy metering linked to central BMS. The office and toilet AHUs have heat recovery incorporated within each unit to ensure maximum efficiency. A heat recovery unit is dedicated to the basement amenity space. All ductwork associated with heat recovery plant is thermally insulated.

Summary of sustainable features

• Replacement of façade with high insulated cladding
• Improved U-values within the façade cladding
• Insulated suspended ground slab above basement areas
• Insulated roof level
• Heat pump heating and cooling
• Removal of natural gas
• Heat pump for domestic hot water
• LED lighting throughout
• Lighting control including PIRs
• Energy metering
• Water reduction in sanitaryware selection – low flush, sensor operated flow
• External light pollution reduction
• Recycled building materials
• VSD on fans/pumps
• Leak detection

Overall, taking the existing footprint of the building from a D2 to an A3 BER energy rating, while improving the envelope aesthetics of the development, increasing the lettable area and achieving LEED targets, has been a successful project for the client and full project team.