Power conservation in single-family homes yields benefits for the economy and the environment
Daphne Berenskiöld chose to do her thesis while at FVB. This choice also led to her getting the award for best thesis from Swedvac. Her work was entitled “Attenuation of outdoor temperature sensors in small properties” and she shares her results here.
Environmentally-friendly energy sources have the potential to produce a large amount of energy spread out over the year. However, they have a hard time maintaining sufficiently high power during cold winter days when many people need electricity and heat at the same time.
“In some cases, fossil fuels need to be used to accommodate the power peaks, which is both expensive and bad for the environment,” Daphne reports.
“At the same time, energy companies are putting more and more emphasis on power output. This is why power conservation can lead to both environmental benefits and economic savings for the homeowner.”
Using attenuation
The idea of Daphne’s thesis was to test how a heating system can react at an appropriate rate for the building using attenuation. She received a lot of support and knowledge from Johan Söderberg and David Ekström at FVB during her work. Direct attenuation of outdoor temperature sensors works by manipulating the output signal to believe the outdoor temperature is different than it is. It can also be done by changing the temperature slower than the actual outdoor temperature changes.
“This is done so the heating system will react more slowly and compensate for the building’s thermal inertia,” Daphne explains. This way, you reduce the power peaks and create a more even indoor temperature.
Thermal attenuation
Today, there are more and less advanced programs that reduce the power demand for heating by analyzing the building’s thermal inertia and attenuating the fluctuations in temperature. Common to most of these is that they are integrated into the heating system from the start, which makes them unsuitable for existing systems. They can also be designed for larger buildings and not useful for single-family homes.
“My thesis investigated the possibility of attenuating the outdoor temperature sensor in a different way for these types of buildings, namely thermal.”
Multiple benefits
Temperature measurements were performed in a single-family house to calculate its need for attenuation. Then, attenuation was created with a thermos that contained a suitable “thermal inertia”.
“The measurements showed that it is technically possible to attenuate an outdoor temperature sensor thermally and thus mimic a building’s thermal inertia,” says Daphne.
“The attenuation does not provide much energy savings if the building is heated only with direct electricity or district heating. This is largely due to the fact that the attenuation shifts the energy consumption and evens out the power output.
However, the need to overcompensate the heating level to avoid it getting cold indoors is reduced as a result of the reduced distribution losses, which increases the energy savings. If the house has a heat pump, more energy can be saved, particularly during the autumn and spring, when cool nights would otherwise require an electric heater to be used.
Increased comfort
Daphne’s work showed that the largest savings to be had from attenuation comes from power reduction.
The residents experienced an increase in comfort because the heating system reacted more slowly when changing over to colder weather, as it previously used to get too hot indoors.
“This work has taught me that the inertia in a building has a major impact on the indoor climate. It is important that the heating system works in conjunction with the house,” says Daphne.
The work also shows that even small variations in the indoor temperature can be perceived differently depending on circumstances other than the actual temperature in the room.
“So it is not possible to create an entirely perfect indoor climate just by having an entirely even temperature,” she concludes.
More information:
Daphne Berenskiöld, 08-594 761 87
