Making the right choice

In influencing the choice of heating and ventilation systems architects can ensure these systems support their designs while delivering optimum building performance. Phil Brompton of Powrmatic explains:

As regulations require improved thermal performance of buildings – through better thermal insulation and more airtight construction – the interplay of the building’s design and its services becomes increasingly important. For example, tightly constructed buildings with little or no natural air ‘leakage’ are reliant on ventilation systems to maintain suitable indoor air quality. In parallel, there are very strong reasons to opt for natural ventilation to minimise the building’s carbon footprint, as the only energy consumption required is to open and close the ventilators.

Also, of course, many such buildings will have a requirement for smoke ventilation systems, either separately from the day-to-day ventilation or as a dual purpose system.

Of necessity, these ventilators will need to penetrate the building envelope so this is an area where the architect’s understanding of the options will play a key role in terms of both building performance and aesthetics.

In selecting an architectural solution for smoke and natural ventilation there are a number of factors that should be taken into account. Clearly the ventilators should be fully tested and certified (to EN12101-2) for the application while also offering a design that provides seamless integration into the building fabric to complement, or possibly enhance, the architectural design. For example, there are glazed ventilators for both natural and smoke ventilation that also provide an excellent source of natural daylight and can be integrated into inclined and vertical glazing systems.

Engagement with suppliers should also include discussions around installation options for the type of application (e.g. turn down base for upstands, glazing adapters for curtain walling, fixing flanges or direct fixing to masonry) along with choices of finish to match the building. Other factors to consider when specifying ventilators are their light transmission and U-value specifications, along with independent verification of low air permeability, weather tightness and wind resistance to maximise energy efficiency. The design of the ventilator should also include thermal breaks to prevent cold-bridging, as well as the use of durable materials. These materials should be from a sustainable source, recyclable at the end of life and be manufactured using sustainable processes.

There are additional sustainability benefits to sourcing from a UK manufacturer, as this reduces the overall embedded carbon of the project. Local manufacture also enables a more flexible and responsive approach with the ability to manufacture standard and bespoke sizes to suit each project’s requirements and construction schedules.

Air rotation heating

In the majority of buildings, once the heating system has been designed and installed there is relatively little change to its con- figuration. However, this is not the case with many ‘shed-type’ buildings such as warehouses, factories and some retail outlets.

In these situations the building operator may have a requirement to occasionally – or even frequently – change the layout of the space and if this results in a need to reconfigure the heating system it can prove to be an expensive exercise. In these circumstances it makes sense to opt for a heating design that does not impose such constraints on the building layout. It was in addressing this challenge that a new technology called air rotation heating was developed – initially in the USA but now gaining popularity in the UK.

Air rotation heating works by using high efficiency axial fans to move large volumes of air at relatively low temperatures and velocities through the space with minimum energy consumption, while low temperature operation helps to maximise condensing for further energy savings.

A major benefit of the air rotation heating approach is that it is able to provide excellent temperature control (typically no more than +/-1.5°C of the set point) irrespective of the layout of the space. This also means that any reconfiguration of the space does not impact on the heating or require the heating system to be redesigned, as might be the case with fixed systems.

Meeting the challenges

For all of these reasons, there is a strong incentive for architects to give careful consideration to ventilation and heating as a key part of the design process, potentially working closely with other disciplines and specialist suppliers to arrive at the best solution for the end client.