by Professor Risto Kosonen
The effect of the cold winter on the sufficiency of power and energy prices is thought-provoking. Public bodies have prepared for this with energy-saving campaigns. In addition, several property owners have drawn up instructions on how to reduce energy use. So much has been learned from previous energy crises that the importance of indoor climate is emphasized in several guidelines. In professional society, the importance of indoor climate is understood both in terms of human health and the long-term functionality of structures, but then it remains to be seen how the average resident will perform.
There is no going back, and, likely, the price of energy will permanently remain at a higher level than before. The slowdown of global warming requires expensive investments in energy systems, and we must quickly get rid of fossil burning. In the future, energy production must be based mainly on the use of renewable energy, the output of which varies significantly daily. Due to fluctuating production, the peak power of buildings has to be managed better than at the moment. We are moving from optimizing energy use to power management. In this balancing energy production and consumption, buildings play a significant role, which, however, requires improving the smart readiness of buildings and also local energy storage.
During Corona, we learned how to work remotely and now we have started returning to our jobs. They have learned to work remotely so well that many workplaces have to attract employees to come back to the office. It is clear that the ways of working are changing and the ratio of remote work will be significant in the future in jobs and tasks where it is possible. In the future, office buildings will function more and more as meeting places than as spaces intended for actual work. This means that the number of people in the offices and their different premises vary significantly.
In terms of energy use, demand-based ventilation is an effective way to manage varying numbers of people in such a way that the air quality remains good and energy is not wasted. Ventilation is used where and when workers are present, where different sensors control the operation of the ventilation.
In the last years, it has been learned that the ventilation of buildings is of great importance in the control of airborne respiratory infections. In terms of the risk of infection, adequate ventilation for the people present must always be ensured in pandemic situations. Now, as we move towards winter, pandemic cases are becoming more common. It is good to keep this in mind when controlling the ventilation.
Management of indoor climate and energy use requires systems that perform according to plan. In the conducted studies, it has been found that there are shortcomings in the performance of the HVAC- systems, and the monitoring of the system operation is in many cases neglected. Several technically complex demand-based ventilation systems do not work as they should. Several of these deficiencies could be easily corrected if the operation of the systems was monitored better.
It has been said that data is the new oil. The utilization of data enables completely new services with which optimal control of building services is possible. In the efficient utilization of data, the operation of the technical systems and the correctness of the measurements must be ensured. Now, during the energy crisis and infection cases becoming more common, ensuring the operation and the correctness of the set values is a primary measure that should be done by technical staff.
by Professor Olli Seppänen
Nordic Ventilation Group (NVG) works for better performance and understanding of ventilation and its effects. Topic is now more important than ever. Good ventilation is essential for good indoor air quality, and health of the building occupants. It is known that proper ventilation improves the productivity, learning, health, and even sleeping. During the Covid pandemic it has been shown that efficient ventilation reduces the infections caused by the virus particles in the air.
The other side of the coin is the fact that a lot of heating or cooling energy escapes from buildings with exhausted air, totally it can be 5-10% of total national primary energy use. Most of the new buildings in Nordic countries recover the heat from the exhausted air by heat exchangers, in some countries heat recovery is mandatory even in the residential buildings. This reduces significantly the energy need of buildings.
Energy saving is currently the focus in EU. Energy use could be reduced drastically by stopping heating and ventilation, of course, this should not be done. If space heating and ventilation is reduced, it must be done very skillfully so that the indoor environmental quality is not deteriorated. Severe moisture and IAQ damages, caused by low ventilation and heating are still in the mind of professionals.
Hopefully, current need to reduce energy use do not repeat the mistakes done before. It is extremely important to maintain adequate ventilation in the occupied spaces of the buildings. Energy savings can, however, be achieved targeting heating and ventilation better into the rooms and areas where occupants are. Empty or partly occupied room do not need the same amount of ventilation or even heating than fully occupied spaces. Large potential for energy savings can be achieved with the better targeted ventilation and heating.
HVAC systems can be complex and require regular maintenance and adjustment to the changes in the use of the building. Regular inspection of ventilation is needed. Inspection is mandatory in most countries in the new buildings but not in existing. Need for regular inspection has been realized, first in Sweden, where the ventilation inspections have been mandatory already since 1991. In Finland an official guide for inspections was published in September 2022. Experience has shown that regular inspections are necessary, particularly for the complicated systems, like demand control ventilation (DCV).
Recent Nordic Ventilation Forum showed that the problems in ventilation performance are very common in DCV systems in all Nordic countries. Improvements are needed in the construction process, equipment, automation, IAQ-indicators, and many other areas. Covid pandemic has shown that better controlled ventilation should be available in fight against air borne infections. Current systems are not able to vary ventilation rates at as large range as required for good energy efficiency and air quality. New criteria for ventilation rates and design are needed and put in practice.
A major task of NVG is to collect, develop and share the knowledge of the better performance of ventilation. The current activities of NVG are focused on the lessons learned from the Covid pandemic for better design and operation of ventilation including new criteria of design ventilation rates, control by demand, use of sensors in practice, effectiveness of ventilation, and use of air cleaners to assist ventilation.
This blog offers a platform to the NVG members to express their ideas to a larger professional audience. In a long run it will be a significant source of information to bodies involved in development of new ventilation and IAQ technology.