DESIGN FOR WELLBEING
The environments where we live and work have a direct impact on our wellbeing, from our sleep/ wake cycles and mood to productivity and performance. Indeed there is a large body of research that convincingly demonstrates that the design, construction and operation of buildings have a substantial impact on the health and wellbeing of their occupants.
Furthermore, the evidence shows that there is a clear difference between internal environments that are simply not detrimental to health and those that positively support and enhance health and wellbeing. For workplaces, where staff-related costs typically represent 90% of operating costs (energy and rental related costs typically represent 1% and 9% respectively), anything that can help to make a workforce productive can have significant impacts on an organisation’s bottom line.
The importance of an HVAC system in commercial and residential buildings cannot be overemphasized, but is sometimes overlooked. It is well known that outside air pollution is harmful to health and over the years a number of initiatives have been undertaken to improve and reduce these levels.
A good ventilation system will not only meet the ventilation requirements of the building but will also meet its temperature comfort conditions. This is where mechanical ventilation has its advantages as it can be combined with a gas fired heating unit to meet winter conditions. Freecooling, will in most cases, help to lower the space temperature when it creeps above the desired set-point. And for when those summer time temperatures cause the mercury to rise even higher, a mechanical cooling system will be necessary to improve comfort conditions for the occupants.
Modern equipment can combine many of these functions in one system. For example, the Reznor RTU range is composed of air-to-air heat pumps, packaged with various heat recovery options and gas fired heating coils to maximize efficiency. All units are equipped with high efficiency G4 class air filters. Fresh air and ventilation options provide a high level of indoor air quality and help ensure a clean and comfortable conditioned space.
Air quality
Operating an HVAC system at optimum efficiency is a challenging endeavour. The number of set points, levels and feedbacks of boilers, chillers, pumps, fans, air delivery components and more can cause costly inefficiencies. Add to that the fact that weather variables affect the heat transfers in a building and increase loads on the HVAC.
According to the Environmental Protection Agency (EPA), poor indoor air quality is among the top factors of environmental risk. Pollutants in the air can aggravate allergies and asthma in some people and cause dizziness and headaches in others.
Air quality depends on various factors. Too many people within a poorly ventilated space will cause an increase in poor air quality. Good levels of air filtration will help remove larger pollutant particles from the airstream and is necessary to maintain good levels of air quality.
Environmental changes
Natural ventilation can improve indoor air quality by reducing pollutants that are present indoors assuming that those outside are in fact cleaner.
Humidification also plays a part in the improvement of air quality, particularly in environments such as hospitals. Humidity control is essential to many applications; from healthcare and labs to anywhere equipment productivity is vital. Humidification units use the latest advances in technology to optimize the reliability and effectiveness. The systems are able to adapt to environmental changes and deliver on promises of energy efficiency.
Relative humidity can be seen to have a similar impact on bacteria as it does on viruses, in that intermediate RH conditions have a considerable influence on bacteria survival, both airborne and on surfaces. A high death rate of airborne pneumococci, streptococci and staphylococci is seen at intermediate RH levels. Furthermore increased decay of a hospital strain of staphylococcus is seen at higher humidity levels.
Obviously, high relative humidity conditions are to be avoided; excessively high humidity (above 70%) is associated with mould growth and the multiplication of house dust mites, and these can have adverse implications for asthma and allergy suffered. Mould, once established, will continue to grow even at lower humidifies and so continue to release musty odours.
Danny Packham is European product manager – Warm Air and Radiant for Nortek Global HVAC UK
