Throughout the last decade there has been a clear trend towards more insulation, airtight construction, and optimal use of solar gains. However, recent research has pointed out that the actual energy use in buildings is typically underestimated for very energy efficient buildings, whereas overrated for poorly insulated buildings. This is partly caused by user behavior, but primarily due to the evolution towards condensing boilers and heat pumps requiring low temperature distribution systems, which in turn lead to slow systems that are put on 24/7. The envisioned gains due to more energy efficient technology are superseded by the transition towards uniform and continuous systems for heating, cooling, ventilation, domestic hot water, and the electrical installation.
In the competition we will focus on demonstrating the potential of demand controlled services. Space heating and cooling should be controlled in space and time in accordance with the user behaviour. Hence, we will rely on IoT technology in which automated use of the smartphone will adjust the set-point temperatures. If your IoT updated GPS knows when you will be home, your house can also anticipate to your arrival by preheating the house. In order to enable this dynamic behavior, we need a fast responding system and minimal thermal mass. The distribution consists of a hydraulic system with dynamic microfan assisted convectors with a very short response time to rapidly adjust to the demand profile.
A demand-controlled exhaust system with self-regulating air inlets is adopted for ventilation. The required air flow rates are calculated for each room based on the carbon dioxide levels (tracer for human presence), relative humidity (cooking and bathing), and volatile organic components (odors). By adjusting valve settings and fan speed the air flow rates allow to optimize the trade-off between good indoor air quality and increased energy use. Due to the highly effective control algorithm, this system is preferred over a full mechanical system with heat recovery due to the additional cost, maintenance, electric fan use, ductwork, and as well, the embedded energy to manufacture these items. The ventilation system is completely IoT controlled, which allows for control updates, online performance assessment and automated system diagnostics.
Although we typically only need domestic hot water of 40°C, water in boilers is typically stored at 60°C to omit the risk for legionella infection. By consequence, we see that the required energy for domestic hot water often even outweighs the energy use for space heating in energy efficient buildings. Hence, Ghent University has developed a patented technology that allows to adopt a variable temperature regime in the boiler, based on predictive modeling that calculates the growth of the biofilm and legionella in the system. This approach allows for a significant reduction in energy use, while maintaining the safety levels of the domestic hot water installation.
There is a clear mismatch between the electrical production cycle of solar panels during daytime, and the household electricity demand which is predominantly in the morning and evening. This undermines grid stability, and in some neighbourhoods the effective production of PV systems is reduced by 50%. Electrical storage is an effective way to balance this, but also necessitates an optimized energy management to ensure optimal use of the capacity by linking the electrical storage to a thermal storage system to expand the buffer potential.