Energy and Buildings

Journal: Energy and Buildings

Abbreviation

Energy build.

Publisher

Elsevier

ISSN

0378-7788
1872-6178

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Publications1 - 10 of 96

Stuck in a stack—Temperature measurements of the microclimate around split type condensing units in a high rise building in Singapore
Bruelisauer, Marcel; Meggers, Forrest; Saber, Esmail; et al. (2014)
Energy and Buildings
The use of air-conditioning, the largest energy demand for buildings in the tropics, is increasing as regional population and affluence grow. The majority of installed systems are split type air-conditioners. While the performance of new equipment is much better, the influence of the microclimate where the condensing units are installed is often overlooked. Several studies have used CFD simulations to analyse the stack effect, a buoyancy-driven airflow induced by heat rejected from condensing units. This leads to higher on-coil temperatures, deteriorating the performance of the air-conditioners. We present the first field measurements from a 24-storey building in Singapore. A network of wireless temperature sensors measured the temperature around the stack of condensing units. We found that the temperatures in the void space increased continuously along the height of the building by 10–13 °C, showing a significant stack effect from the rejected heat from condensing units. We also found that hot air gets stuck behind louvres, built as aesthetic barriers, which increases the temperature another 9 °C. Temperatures of around 50 °C at the inlet of the condensing units for floors 10 and above are the combined result, reducing the unit efficiency by 32% compared to the undisturbed design case. This significant effect is completely neglected in building design and performance evaluation, and only with an integrated design process can truly efficient solutions be realised.
Post-Insulating traditional massive walls in Southern Europe: A moderate thermal resistance can be more effective than you think
Posani, Magda; Veiga, Rosário; Freitas, Vasco (2023)
Energy and Buildings
Post-insulating existing buildings is a promising solution for reducing operational CO2 emissions from the European built environment. Nonetheless, its efficacy is unclear when traditional and historic massive walls are considered, especially in Southern Europe. This study employs a validated and calibrated dynamic hygrothermal simulation model to assess indoor comfort and energy demands in a public library with thick stone masonry walls and intermittent occupation, considering three Southern European climates: Porto, Lisbon, and Bologna. Five insulation materials, including three thermal mortars and two conventional materials (Hydrophobic Mineral Wool and Expanded Polystyrene), are compared using internal and external insulation solutions. Thin insulation systems (4 cm) with moderate thermal resistance (Rt = 0.3–1.0 m2K/W) are studied and found to provide more benefits than drawbacks. One thermal mortar-based system demonstrates comparable performance to conventional insulation materials, indicating that low-conductivity thermal mortars are effective for retrofitting historic and traditional massive walls. Numerical analyses show that optimal reductions of energy demand can be achieved with an insulation Rt of 0.9–1.3 m2K/W, while further increases yield no additional benefits and even counterproductive outcomes. Results support adopting moderate Rt insulation in Southern European climates and highlight the need for future research considering the effect of post-insulation on climate change adaptation.
A scalable approach for real-world implementation of deep reinforcement learning controllers in buildings based on online transfer learning: The HiLo case study
Coraci, Davide; Silvestri, Alberto; Razzano, Giuseppe; et al. (2025)
Energy and Buildings
In recent years, Transfer Learning (TL) has emerged as a promising solution to scale Deep Reinforcement Learning (DRL) controllers for building energy management, addressing challenges related to DRL implementation as high data requirements and reliance on surrogate models. Moreover, most TL applications are limited to simulations, not revealing their real performance in actual buildings. This paper explores the implementation of an online TL methodology combining imitation learning and fine-tuning to transfer a DRL controller between two real office environments. Pre-trained in simulation using a calibrated digital twin, the DRL controller reduces energy consumption and improves indoor temperature control when managing the operation of a Thermally Activated Building System in one of the two offices both in simulation and in the real field. Afterwards, the DRL controller is transferred to the other office following the online TL methodology. The proposed approach outperforms a DRL controller implemented without pre-training, and Rule-Based and Proportional-Integral controllers, achieving energy savings between 6 and 40% and improving indoor temperature control between 30 and 50%. These findings underscore the efficacy of the online TL methodology as a viable solution to enhance the scalability of DRL controllers in real buildings.
Use of model predictive control and weather forecasts for energy efficient building climate control
Oldewurtel, Frauke; Parisio, Alessandra; Jones, Colin N.; et al. (2012)
Energy and Buildings
Influence of the urban microclimate in street canyons on the energy demand for space cooling and heating of buildings
Allegrini, Jonas; Dorer, Viktor; Carmeliet, Jan (2012)
Energy and Buildings
Overview of occupant-centric KPIs for building performance and their value to various building stakeholders
Sleiman, Sleiman; Ouf, Mohamed; Luo, Wei; et al. (2024)
Energy and Buildings
Recognizing the significance of occupants and their interactions with the building's operational systems, various occupant-related key performance indicators (KPIs) have been established. However, there remains a notable gap concerning the practical utilization of these indicators by building stakeholders. Therefore, this study provides a comprehensive overview of the occupant-related building performance KPIs and how various building stakeholders influence them through their decision-making. The study assessed: (1) roles of various building stakeholders; (2) stakeholders’ requirement for occupant-centric KPIs in their decision-making process; (3) factors demonstrating effective occupant-centric KPIs along with data requirements to evaluate them; and (4) stakeholders’ decisions and actions that affect occupant-centric KPIs. Key stakeholders identified involved investors, building owners, designers, building occupants, building managers and operators, as well as utility providers. Effective occupant-centric KPIs were characterised by their fit-for-purpose, actionability, quantifiability, comparability, reproducibility, integrability, feasibility, and usability. Results indicated that building managers and operators primarily affect thermal, air quality, and visual KPIs. Building occupants, public authorities, investors, building owners, and designers influence all categories of occupant-centric KPIs. Utility providers particularly impact thermal KPIs. In conclusion, findings of this study contribute to shaping the way in which stakeholders consider occupants in their decision-making to achieve building performance objectives by data-driven occupant-centric KPIs.
Do energy performance certificates allow reliable predictions of actual energy consumption and savings? Learning from the Swiss national database
Cozza, Stefano; Chambers, Jonathan; Deb, Chirag; et al. (2020)
Energy and Buildings
The thermal performance gap in buildings is defined as the difference between the theoretical and the actual energy consumption for heating, and is known to undermine energy retrofit strategies and policies. This study examines the performance gap in retrofitted buildings using the Swiss Cantonal Energy Certificate for Buildings (CECB) database, using a sample of 1172 buildings for which both theoretical and actual metered consumption were known. We found an average negative performance gap of –23% for pre-retrofit buildings (actual consumption smaller than calculated) and instead a good approximation of actual consumption with theoretical consumption after retrofitting (a positive gap of 2%). A regression analysis on the energy performance certificate input parameters characterizing the building led to the conclusion that these are poor predictors of actual consumption compared to the theoretical calculation: parameters such as the energy label and the thermal proprieties of the envelope (U-values) have minor explanatory power for the actual consumption despite explaining a high degree of change in the theoretical consumption. Analysis of the indicator Energy Savings Deficit (ESD) shows an overestimation (of 37%) of the achievable savings on the basis of the theoretical consumption, whereas the prediction of savings using measured consumption before retrofit resulted in a good agreement with the actual savings (3.6% overestimation). This implies that energy savings can be estimated rather accurately by comparing the actual current consumption with the expected theoretical consumption defined by the certificate after retrofit.
A reflective adaptive solar façade for multi-building energy and comfort management
Powell, Daniel; Hischier, Illias; Jayathissa, Prageeth; et al. (2018)
Energy and Buildings
Decentralized cooling and dehumidification with a 3 stage LowEx heat exchanger for free reheating
Baldini, Luca; Kim, Moon Keun; Leibundgut, Hansjürg (2014)
Energy and Buildings
Exploring the gap between carbon-budget-compatible buildings and existing solutions – A Swiss case study
Priore, Yasmine D.; Habert, Guillaume; Jusselme, Thomas (2023)
Energy and Buildings
Challenging climate goals demand immediate greenhouse gas emissions reductions for long-term temperature stabilization. Given the nearly linear relationship between warming and cumulative net emissions, the carbon budget approach is a useful tool to quantify remaining carbon allowances for countries, sectors, and even buildings. The built environment plays a crucial role in today’s carbon emissions and future reduction potentials. Although much progress has been achieved towards energy efficient buildings, less attention has been given to the impact of materials put in place. Furthermore, the construction sector lacks of quantified reduction efforts and time horizon limits to clearly define a climate neutrality pathway. This article proposes a definition of yearly targets until 2050 for the operational and embodied carbon of buildings in line with a global 1.5 °C carbon budget and the Swiss climate strategy. The proposed targets are then compared with the impact of current practices and future technical developments. Gaps between targets and practices are quantified and discussed to better understand the upcoming challenges of the Swiss construction sector.

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