AIR QUALITY Keep control around the clock
Jon Belfield, president of the Building Controls Industry Association (BCIA), discusses the negative impact a poorly ventilated working space can have on staff productivity and explains the environmental benefits of night cooling.
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n our somewhat unpredictable UK climate and with all four seasons sometimes occurring on the same day, the task of managing the temperature in our buildings can be a tricky one, even more so with modern energy efficiency targets to meet. With wellbeing in the workplace also ranking high on the list of an employer’s objectives, it is essential that building managers have effective techniques in place that maximise a building’s ability to regulate its temperature with minimal effort required from its occupants. When we’re at home most of us are conscious of the ways we can save on our energy costs and the concept of #onesmallchange is instinctive. We switch off lights in unoccupied rooms, we hang up our washing instead of using the tumble dryer and we’ll open a window if it’s too warm in summer. These simple habits come more naturally to us when we’re at home – perhaps this behaviour is because we’re the ones paying the bills! However, once we get to work, who among us can truly say we haven’t been a little lazy or forgetful when it comes to taking our green credentials from home into our work place? I read a great statistic recently that goes some way to explaining the potential impact of our behaviour on energy: Two identical saloon cars are both covering 18,000 miles per year – one a company car and one privately owned. The privately owned car used significantly less fuel than the company car. Please don’t take this as being the same in every case, but you can see how the same car or building can perform differently due to different ‘behaviours’.
Workplace wellbeing
Poor building management can be a factor in workforce dissatisfaction. In 2016 global research firm Ipsos carried out a study on behalf of Steelcase, the leading workplace solutions provider. The study found that UK workers are the least satisfied with their office ambience, with 33% of workers saying they don’t like their office environment, suffering from a lack of control over making it suit their needs.
Nearly half (45%) of UK workers are dissatisfied with the room temperature at work, and 32% are unhappy with the light intensity.
Only 39% of respondents said they could adjust the office temperature, and only 21% were able to alter the lighting.
Whether we take these statistics literally or not, the underlying basic point is that these factors can have a serious detrimental effect on the concentration, productivity and engagement levels of workers, with the study showing that a lack of flexibility and control over the physical work environment correlates with a lack of engagement and lower productivity. In contrast, highly engaged employees are those that have the most flexibility over how and where they work.
Long, hot summer
Let’s go back to the summer of 2018, the UK’s joint hottest on record, and, for England supporters at least, a more enjoyable World Cup than we’ve experienced for many a year! The warm temperatures, in most cases, raised people’s spirits, whether we were at the beach, in a pub garden or attending a family barbecue. But going back into work on a Monday morning in a hot office that hasn’t had any ventilation for a couple of days brings us all back to reality, and we start counting down the hours or days until we can be outside enjoying the sunshine again. This could be bad news for your productivity levels, but there are ways you can ensure your building is at a suitable temperature, and building controls play a key role.
As Building Energy Management Systems (BEMS) designers, we have a responsibility to ensure conditions are achieved efficiently but must trust occupants to make adjustments to suit their needs – it is a shared responsibility for the space and the energy that provides that space in the same way as previously mentioned when the quoted efficiency of a car can be influenced so much by user behaviour. A recent directive proposing speed limiters to be mandatory on all new cars after 2022 would restrict the ‘behaviour’ element for speed and efficiency. In many ways, we already have this in buildings with BEMS whereby the ‘zone’ setpoint might be 19˚C and the local adjustment allows for a plus or minus of 3˚C, giving a minimum of 16˚C and a maximum of 22˚C.
Modern advancements in building technology mean that we can now cool buildings more efficiently, particularly buildings with high numbers of occupants, such as schools, hospitals, office buildings and factories.
Night cooling
We can use technology to cool our buildings at night through night cooling, also known as night purging, which uses a building’s thermal mass to absorb heat gains during the day before cooling the mass at night using external air.
The accumulated heat is discharged to the outside, thus lowering the temperature of the thermal mass. For night cooling to be effective a building requires significant thermal mass to be exposed to both the occupied spaces of the building and to its ventilation paths. Night cooling can be achieved naturally (through open windows) or mechanically with fans. Natural ventilation is not always ideal because it relies on natural ventilation, which ultimately means leaving openings in the building’s external shell to allow the air to pass through. For buildings where security is a particularly important issue this is obviously not suitable.
By using a BEMS we can monitor the temperature levels inside and outside the building and use the information to determine the amount of cooling required. Fans can be controlled by the BEMS to drive the required amount of air through the thermal mass and target the areas where it is most needed. Because of this, air ducts can be smaller, therefore reducing security risks and potential noise issues.
Subtle blend
There is a subtle blend of actual ability to make real changes to an environment and the positive feeling that can be achieved by just knowing that you can make a change, no matter how small. This comes back to a shared ownership and responsibility for the space, with BEMS engineers, facilities managers and occupants all seeking to keep energy consumption down to a realistic minimum.
www.acr-news.com June 2019 19
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