A list of seven actions for increased energy efficiency
The below list has been created as this part of the guide is giving advice on farily separate actions. It is possible to enter the guide at the topic of interest by clicking the links, but it can also be read from top to bottom.
It is worth knowing that the suggested actions for ventilation, heating and cooling (HVAC) are not seasonally bound. They will make a difference to the energy dependency no matter if a building is entering a season of heating, or a time of cooling.
- Revise the HVAC solution to make sure everything works as inteded
- A good maintenance plan is not only to upkeep, but to also improve
- Clean ducts minimise the risk of large pressure drops
- The air handler's many functionalities are there to optimise and save energy
- Align temperature set points between all heating and cooling systems
- Understand the relation between outdoor sunlight and indoor climate
- Consider making seasonal adjustments to the indoor temperature
Make sure everything works as intended
Starting with an example, a business establishes a suburban office for employees to escape commuting. This can affect the occupancy in the original office, which in turn might need adjustments of the ventilation, heating and/or cooling to ensure a comfortable indoor climate and an energy-efficient operation. Another example, dampers that are not operating correctly are significant energy consumers. A damper, motorised or not, that is opening and closing inaccurately will cause unnecessary energy consumption due to large pressure drops and faulty air flows.
The fact that an indoor climate solution is in place is not an insurance of everything working precisely. It can very well be worth to revise a solution to make sure tangible parts are installed and commissioned as intended and that the available functionality in system controls are used to its best ability. Make sure everything works as good as it possibly can, and be aware that the use of a building can change and that adjustments might be needed to ensure an upkept energy efficiency while still offering a good indoor climate for the people inside.
A lot starts with maintenance
Even the most well-adjusted air handling unit can cause pointless energy consumption. The most obvious, and hopefully well-known, reason is the need for clean filters and ducts. Not only will filled filters and dusty ducts cause the air handling unit to run more intensively, there is also a significant risk of damaging the AHU’s fan or causing disturbing noise to the indoor environment.
A good maintenance plan is not only an important factor as such, good maintenance is also to do things right. For instance, it is important to make sure that new filters in an AHU are mounted correctly when changed. A falsely fitted filter will, just like the dusty filters or ducts, cause pressure drops that adversely affect energy consumption.
Hydronic systems should be vented, and any presence of oxygen should be avoided to avert magnitite. Magnitite can cause pressure drops, negatively affect the system operation, cause potential malfunction and, in the end, increse the use of energy. With that said, a properly pressurised hydronic system will ensure an energy-efficient solution.
The air handling unit is key
Many air handling units (AHUs) have clear opportunities to reduce energy consumption. This because they ever so often operate on irrelevant time-schemes, target unnecessarily high temperatures or run with air flows that, actually, may impact the indoor climate negatively.
To exemplify, AHUs operating as if an office is occupied all day, every day, ought to be considered energy-inefficient. Generally, neither traditional office patterns nor hybrid working models require a highly ventilated, heated or cooled office during night-time or weekends. It is first and foremost recommended to use functionalitites to schedule operating times, and if such functionality is in use, make sure the set timeframes are relevant for the use and need inside the building. Read more in our expert’s blog about how to come to terms with this and other issues that affect the energy consumption, and perhaps also the indoor climate, negatively.
Read our expert's blog for further tips
Make sure to not heat and cool at the same time
It happens quite often that a room is both heated and cooled at the same time. A critical energy-failure that can happen if heating and cooling respectively is carried out by different solutions. To exemplify, if a climate module, radiant ceiling or fan coil has a different temperature set point than the set point for radiators in the same space - a room can be both heated and cooled at the same time.
An easy recommendation to save energy is therefore to make sure temperature set points are aligned between the solutions that ensure heating and cooling in a room. There should be no need to open the window and let the energy out of the building.
To heat and cool at the same time, in the same space, is perhaps the worst energy failure in relation to HVAC.Carl-Ola Danielsson, Research & development manager, hydronic products at Swegon on the topic of ventilation, heating and cooling of a building
Energy before comfort can be costly
To set the temperature span in which adjustments can be made by the people inside the building is a reasonable measure to lower the energy consumption in a building. However, far too often the temperature limits are set way too low. Energy is prioritised, while comfort and productivity inside the building is somewhat neglected.
It is important to keep the history in mind, energy before comfort can turn out to be very expensive if tenants are reluctant to stay, and pay, due to an uncomfortable indoor climate.
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Sunshine, day-light and indoor climate
It is well-established that daylight has a biologically positive effect on the human body and affect our ability to sleep, decrease our stress levels and counteract mood swings.
However, natural day-light, and more specifically sunlight, can bring an enormous amount of energy into a building which is important to understand when creating good indoor climates. Depending on the building envelope, including isolation, window characteristics etc, the bright light is let in as more or less heat. By understanding the building construction, the conditions for a good indoor climate as well as the effects from using existing or additional sun-shading, heat energy can be used efficiently and reduce the need and consumption of energy in relation to heating and cooling.
A changing temperature span
Read the above and presume a temperature span has been chosen that allows for overall energy efficiency as well as a good indoor climate. That temperature span may be slightly shifted to warmer or colder degrees in different seasons, which means that the temperature adjustments granted inside the building, in a way, follow the outside temperature.
This is a reasonable measure for energy-savings for two main reasons. First, people are most often dressed for the outside weather even if they are spending most of their day indoors. Meaning, people are usually dressed lightly when the outside temperature is higher and wamer clothes are worn during the colder season. Second, the human body is generally not made for vast temperature changes, especially not for going from hot temperatures to much colder. Again, this allows for a somewhat wamer indoor temperature during the summer and a little colder during the chilly season.