Control

Yes the set points can be changed, but Breathing Buildings must do this. If the room is found to be too cold in Winter then we can return to installations in order to install a new control programme to change the set points.

Our system can control the heating if a complex heating control system is required in order for our ventilation to work efficiently. However it is usually sufficient for heating to be controlled on a thermostat linked to room temperature.

Control is the critical aspect of natural ventilation and one that we spend a great deal of time understanding. To ensure a pleasant environment we monitor the temperature inside and outside the space, the CO2 levels in a space and the temperature of the supplied air. Of course all this is pointless unless you can understand the science behind your strategy, an area in which Breathing Buildings academic excellence allows us to accept design responsibility for our schemes.

We provide an operations manual for all our installations that help to understand the system and how it operates. If requested we can also provide a single sheet overview of how our system works, for distribution to the users of the space. We ensure that users know how to use the system by performing a client demonstration once the building is occupied.

It is important from the outset that users understand that the system is not air conditioning and therefore does not guarantee internal temperatures.

No. Often mechanical ventilation systems are not as accurately controlled as people believe. For example, the local area around a mechanical system's delivery duct is susceptible to temperature gradients in the same way as an opening on the facade of a building. Issues of temperature stratification within a building, conflicting perceptions of thermal comfort, and air quality issues often arise with mechanically ventilated systems, especially in larger spaces with heat loads at multiple levels.

Manually controlled, Natural ventilation typically also has significant problems with these issues. The challenges of temperature variations etc. are reduced dramatically when a controlled natural ventilation system is used. The optimum solution is usually a hybrid control – part manual, part automated, natural ventilation design.

The benefits of natural ventilation are prominent in the reduced energy consumption of the heating, cooling and ventilation systems. Of course the conditions inside the building aren't going to be completely independent of those outside, and the occupants of the building should be made aware of this as early as possible.

When the building has lots of exposed thermal mass, such as concrete or food stock in supermarkets, we can use the night cool function to keep the temperature down.  With a lightweight construction when it is hot outside a building with no cooling is likely to warm up too whether naturally or mechanically ventilated.

If the e-stack system is required to talk to the BMS then it can either be hard wired (usually in smaller projects) or we can communicate via MODBUS links.

The system is automatically controlled based on internal temperature and CO2 and external temperature. User control is minimal, an on/off/test switch which is usually always kept in the on position except for maintenance. If low-level windows are manually operated then a blue/red LED indicator provides guidance as to when to open and close the windows, but the users still have control.

The e-stack roof based system operates a Summer/Winter mode driven by an outside air temperature threshold, switching automatically between upwards displacement ventilation and mixing ventilation.

The units are sized to provide sufficient air flow to prevent summertime overheating. This is often a much larger volume of air than is required for minimum ventilation, and therefore a large area is required.

Most of the time this is not required as the question of when to open the windows is pretty intuitive. We supply a red/blue light LED indicator to advise users when to open windows.

If automated windows are required, for example when they are at high level, then the e-stack will provided enable signals to actuators.