On Wednesday, August 31st, The Swiss Federal Council outlined measures that could be taken in the event of a severe gas shortage. These include limiting heating in buildings to a maximum of 19 degrees Celsius. Space heating in Switzerland accounts for three-quarters of the gas consumed in winter, and that households, industry, the services sector, and public institutions have been asked to turn down the thermostat. According to the government, one degree less heating can save 5% to 6% of energy.
The interest in the energy and building sectors, however, had already been renewed by climate change communities and initiatives (such as the IPCC), long before Europe’s energy crisis. Globally, the building sector accounts for 36% of the final energy consumption, which turns the spotlight on the building sector in the energy crisis. In Switzerland, the figure is as high as 45%, with space heating accounting for 67% of the building sector’s final energy demand. In other words, 30% of the final energy consumption in Switzerland is accounted for by space heating in the building sector.
Overheated offices constitute a big saving potential
Thanks to indoor air quality data collected from more than 300 office buildings spread all over Switzerland (from small office spaces to the biggest ones like the Circle at Zurich airport), we have observed an average indoor air temperature of 22 degrees Celsius (i.e., a 3-degree Celsius deviation from the current recommendation) over the last heating period. Hence, the recommended temperature set point of 19 degrees Celsius by the Swiss Federal Council holds the promise to save 15% to 18% a year on space heating in commercial buildings. Extrapolating this saving on space heating to the entire building stock in Switzerland, it is estimated that 10-12 TWh of energy can be saved per year, representing about 30% of the Swiss natural gas imports in 2021.
Besides over-heated Swiss office spaces, our data revealed over-ventilation practices, due, most likely, to the health and safety measures after the COVID-19 pandemic, calling for costly shortcuts like non-stop (or maximum allowable) ventilation. Increasing the observed CO2 set point of 550 ppm to 1000 ppm, well within the acceptable range by health regulations and building standards, can help save potentially 10% of buildings’ total electricity consumption over the heating period while mechanical ventilation systems are running at half capacity.
This, in turn, leads to a reduced exchange of indoor and outdoor air, and thus to an additional saving potential on the space heating which would have been consumed to heat up the fresh cold outside air. We estimate that a 50% reduction in ventilation practices over the heating period can save up to 40% of space heating energy demand in commercial buildings, equivalent to about 35% of the Swiss natural gas imports in 2021.
Saving energy without compromising comfort
New combinations of predictive control with real-time data-driven health metrics offer promising possibilities to regulate the indoor climate of residential and office buildings automatically, cost-effectively, and energy-efficiently, with no compromise on occupants’ well-being and comfort. Thanks to the proprietary cloud-based indoor environment data analytics software (OxygenX) we provide, building owners and operators have an opportunity to deal effectively with two pressing yet often conflicting objectives: reduce the environmental impact of buildings to help meet energy-saving goals; and optimize indoor air quality to support the occupant wellbeing and comfort.
OxygenX is a scalable building control solution that enables the optimization of building air quality parameters and energy efficiency in real-time. Continuously collecting and analyzing real-time sensor data on indoor/outdoor air conditions - temperature, humidity, and airborne pollutant levels - along with modeled parameters such as occupancy levels and space use as well as humidification/purification capacities of natural indoor plants, our Software dynamically optimizes building controls to provide a healthier indoor environment at the lowest energy use. In particular, the software optimizes a given space for air quality or energy savings depending on occupancy and indoor plant density (i.e., green leaves per floor area).
What you need to really know is your air quality
Older forms of demand-controlled automation systems typically approximate indoor air quality (IAQ) based on carbon dioxide (CO2) alone. This data is then used to decide when to ventilate. With OxygenX, however, we provide a tool that precisely identifies when to ventilate and for how long by incorporating more than five IAQ parameters (such as CO2, PM2.5, VOCs, NO2, O3, temperature, and humidity). CO2 is a lagging indicator so that occupants can be exposed to IAQ health risks before the high threshold is detected.
Besides utilizing pragmatic health and safety rating tools to optimize ventilation operations and minimize their energy use at no cost to building air quality and occupant comfort, OxygenX quantifies and leverages natural air-humidification and -purification capacities of indoor plants (i.e., plant-assisted saving concept) while managing heating and ventilation energy use.
Using nature to make office buildings more sustainable
The plant-assisted saving concept is a nature-based solution that utilizes CO2 (as well as PMs and VOCs) removal and humidification capacities of indoor plants for saving on ventilation and heating bills. Thanks to removing airborne pollutants from (and/or adding moisture into) the indoor air, a plant-assisted humidification/purification concept helps reduce demands on the fresh air supply (i.e., fewer ventilation operations) that, in turn, allows the conditioned air to remain in the building (i.e., fewer energy losses and less space heating demand over the cold season), resulting in operational savings on the electricity and heating bills, respectively.
Leveraging IoT-based sensor technology and data-driven science-based metrics (including, plant species, space type, and occupancy status) for indoor greenery design concepts, our pilot studies in Swiss office buildings have revealed a potential plant-assisted saving of 10% on ventilation practices, equivalent to about 5-6% saving a year on the space heating demand (i.e., one degree less of heating) in Swiss office buildings. Extrapolating this plant-assisted saving potential to the whole building stock in Switzerland, we estimate 2-4 TWh of energy can be saved per year, representing about 10% of the Swiss natural gas imports in 2021.
To find out more, download our recent publication for free.