Energy certifications are becoming more and more common nowadays. Sometimes, they can be a marketing strategy to make a building more attractive. However, the really important point is the outstanding energy savings that they can provide to a building. The most famous certifications are BREEAM, LEED and Passivhaus. Today, we want to talk about the last one. An amazing case in Candem has been developed. It has been awarded as the biggest Passivhaus residential project in the UK.
Candem case. A Passivhaus neighbourhood
Finding Passivhaus buildings isn’t difficult. However, it is hard to find a big residential unit based on Passivhaus. Agar Grove state, in Candem, is a big residential area with 493 houses. Some pre-existent buildings made even more complex the project. These buildings avoid orienting buildings south to north always what made even more difficult to control solar gains.
District heating. A big problem for Passivhaus
Apart from design strategies to meet the requirements stablished by Passivhaus standard, extra difficulties arose when facing the project. The area was heated by district heating. One of the most restrictive parameters of Passivhaus is the primary energy demand. To simplify this problem, designers decided to reduce, as much as possible, the lenght of pipeworks. In Agar Grove, the boilers weren’t placed all together, but block by block. This helped to the phase development as well as it reduced the pressure and and temperature requirements of the system, diminishing the energy requirements.
Mechanical ventilation. Absolutely required in Passivhaus
Passivhaus buildings are really tight. So tight, that ventilation problems are common. In the Candem case, private and duplex houses have individual MVHR units installed to provide an efficient ventilation. These units are mounted onto the external wall. However, social tenure houses have communal MVHRs.
Heat purging is mainly achieved by opening windows. MVHRs in bypass mode make a small contribution to it. Whether it is noisy outside, windows can be returned to crack position to provide some acoustic attenuation.
This amazing project is a good example of Passivhaus certification in a big residential area. We highly recommend that you visit it if you are close to Candem.
Source: CIBSE journal
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