This is a development of 280 apartments on a brownfield site, a former decaying industrial site, surrounded on two sides by a river valley, which was overgrown and dangerous to access. The valley has been transformed into a public park with pedestrian access to the Luas light rail, bus corridors and a major school complex. The surveillance of the park and access routes by the apartments is vital for their safety. Access bridges and play areas provided in the development increase activity in the valley while also providing a major amenity for the development. The valley and its trees also provide natural shelter for the development.
The development is arranged as a series of compact blocks around a generous central space, which connects through to open spaces surrounding the site. The arrangement of separate blocks of four to seven storeys allows nearly all the apartments dual aspect and good daylight and sunlight throughout the day. This is an important factor in creating a highly sustainable development with very low energy inputs.
The apartments are supported by a crèche and employment in a 400m2 office building. The development is also immediately adjacent to a national monument, Drimnagh Castle, to a major educational campus and to local shopping facilities. Parking is in an underground car park which is affordable in the relatively high density scheme. The parking basement also provides accessible pipe distribution and central boiler house for the development. The development achieves an A3 BER at very low extra cost. The full details of the energy saving features are set out below.
In terms of the building envelope the following key elements were utilised: the insulation specification is 60% above that in the building regulations, the wall construction is traditional blockwork, dry-lined on the inside face with 100mm fibreglass insulation and having a brick outer leaf, thermal mass is used for passive heat storage.
The orientation, glazing positions and detailing were resolved to maximise benefit from solar gain, draught lobbies at ground floor (to avoid heat loss by people coming and going) and extremely high levels of airtightness were achieved through rigorous site practices after the first fix.
The biggest innovation with this development is the use of a district heating system which distributes hot water to the individual apartments. A gas fired centralised boiler room contains 10 modular condensing boilers and the low energy pumps which control the flow and return pipes. The distribution pipes are highly insulated and supply both the hot water demand and the space heating requirement of all the entire development. Residents can enjoy instant hot water and the apartments each have an individual meter which monitors consumption, they are then billed bi-monthly per kilowatt/hour of energy for the hot water they have used. The gas is bought by the management company at the commercial rate, which allows savings to be passed onto the residents.
In addition to this, each apartment is ventilated with an individual mechanical ventilation with heat recovery (HRMV) system. The heat recovery unit is a device that delivers a constant stream of fresh warm air to the apartment by recycling or recovering the heat from air being vented out of the apartment and transferring it to the fresh air being drawn in. About 60% of the heat is recovered, which reduces the need for residents to turn on their heating system. The benefits also include: a constant supply of filtered fresh air, reduced air moisture and reduced allergens in the air, reduced condensation and dust.
The individual controls for both the district heating and the ventilation system have been specifically designed to be user-friendly. The HRMV control is factory-set so the ‘off’ mode corresponds to the background ‘trickle’ rate of air changes and the ‘on’ mode is a booster setting to be used for instance after a shower has been used or after cooking. The heating and hot water operate on simple timer clock timers. The central boilerhome could be readily converted to a renewable energy source . This would be virtually impossible with individual heaters in each apartment.