In this blog we don’t usually write about our products, but we have recently worked on a project that we think will provide interesting insights about preventing overheating in the common corridors of taller apartment buildings.
Aldgate Place E1 is a new city-based residential development by Barratt London, consisting of one-, two-, three- and four-bedroom apartments and penthouses. There are six buildings, ranging from six to 25 storeys.
Overheating resulting from district heating systems
The project relies on district heating systems. This involves circulating Low Temperature Hot Water (LTHW) pipe work through the building via risers and corridor ceiling voids to the individual apartments to provide for their needs. Even when well insulated, there is a risk of overheating within the corridors because of heat loss from the pipe work. This can result in unpleasant conditions for residents and the potential for cold water services to heat up.
Cooling corridors with outside air and its downside
Building ventilation strategy has historically given little consideration to corridors. However, it has recently become common to ventilate corridors with a notional amount of outside air, often via the building smoke ventilation systems.
The downside is that outside air alone only has limited cooling capacity, especially during the warmer summer months, and often the quantity of outside air needed to help mitigate the heat gains is significant, and therefore difficult to accommodate.
The solution: the Colt CoolShaft
CFD analysis shows that corridor temperatures on the warmest design day of the year are between 22-23°C at low level and 23-24°C at high level, so that desirable temperatures are achieved throughout the corridor.To address this issue, we have developed CoolShaft, a combined smoke and day-to-day shaft system which uses evaporative cooling technology to provide active pre-cooling of the incoming air, without compromising the ability of the shaft system to ventilate the common area in a fire. It’s more efficient when temperatures outside rise, and one unit can cool multiple floors due to its greater cooling capacity. That is to say, even on the hottest summer day, desirable conditions can be achieved within the corridors, which would not be possible using outside air. CoolShaft has the added advantage of being suitable for all types of smoke ventilation systems and buildings.
We carried out a study of the overheating in the project’s buildings and used our in-house Computational Fluid Dynamics (CFD) facilities to develop our solution.
Two low-energy Colt CoolStream Evaporative Coolers provide the cooling in combination with low-energy, low-noise, high-efficiency EC fans to provide the air movement through the building. All floors are ventilated simultaneously, ensuring the temperatures in the corridors are consistent. This has the added advantage of not requiring a complex controls system cycling through the floors.
The system consumes no more power than an alternative fan-only system, and significantly less than air conditioning.
Paul Compton is Technical Director for Colt, experienced in smoke control, HVAC, solar shading and louvre systems.
