# Modeling Heat Consumption of an Office Building During COVID-19 Restrictions
## 5 Discussion  
First, an opportunity to achieve similar results in the case of any other office building depends on TRVs and whether the building is equipped with an AHU unit or not. As indicated in the literature, when applying a traditional SH system, hot water moves across the building at almost the same temperature no matter what the mass flow rate is. In other words, hot water moves across the entire building from the DH substation to the most remote space, experiencing a limited temperature drop in the supply line. Hence, without TRVs, the entire building tends to overheat. That means the SH system ensures a minimal acceptable indoor temperature in the most remote spaces while other spaces will overheat. Compared with a hydronic SH system, AHU units do not have to heat the entire office. Moreover, they may be turned on only within the occupied zone. We discussed advancements in experimental and dynamic analyses to evaluate transient effects in building systems, emphasizing the use of detailed models and real-time data to improve accuracy in predicting energy consumption, thermal performance, and occupant comfort. The study showed that night setbacks in HVAC systems could lead to energy savings ranging between 6.4% and 8.2%, as demonstrated in scenarios where SH demand was reduced by 49.7 MWh annually, resulting in 347 EUR/day cost savings. These transient effects, caused by temperature recovery during morning operation, can be analyzed with precision using dynamic simulation tools such as EnergyPlus and TRNSYS. For this case study, setback periods reduced average indoor temperatures from 23.5 \({}^{\circ}\)C to 20.4 \({}^{\circ}\)C under controlled conditions, aligning with optimal comfort levels while enhancing efficiency. The scenario when the thermal inertia was considered revealed that high-inertia constructions reduced peak heating or cooling loads by up to 30%, contributing an additional 5078 kWh in annual energy savings and 228 EUR/day in cost reductions. Similarly, advanced glazing systems with low solar heat gain coefficients can significantly mitigate transient effects. By reducing peak solar gain by as much as 50%, they address up to a 40% variation in internal zone temperatures caused by uneven solar loads, improving occupant comfort by minimizing indoor temperature swings by up to 5 \({}^{\circ}\)C during peak solar exposure. The integration of real-time sensor networks and IoT devices further supports transient analyses. For example, in scenarios where dynamic setpoints were adjusted during unoccupied periods using real-time occupancy detection, energy savings of 10% to 15% were achieved, equivalent to an annual energy reduction of 38.6 MWh with 270 EUR/day in cost savings. Novel control strategies, which analyze transient behaviors in response to weather changes, demonstrated a 15% improvement in energy efficiency compared to traditional control methods, with optimized HVAC configurations reducing fan energy consumption by 20% during transient periods. Occupant-centric experiments underline the importance of adaptive thermal comfort models, showing that temperature shifts of up to 3 \({}^{\circ}\)C can be tolerated without compromising comfort, enabling further energy reductions. This research emphasizes localized thermal gradients' impact, particularly under transient conditions, where optimizing facade technologies and shading devices reduced internal temperature swings, enhanced thermal comfort, and improved energy savings. The combination of these strategies yielded a total annual energy saving of 119.8 MWh (19.8%) and cost savings of 1.89 keUR/day. These findings illustrate the growing sophistication of dynamic analysis methods and experimental validations, which now capture transient effects of HVAC operations, thermal loads, and material behaviors with remarkable accuracy. This progress is crucial for optimizing energy performance and improving the sustainability of building systems under real-world conditions.