Thermal Zoning Research Articles

Methods of determining thresholds of climate variables in building thermal design zoning in China

Climate variable thresholds (CVTs) are essential for building thermal design zoning (BTZ). However, the CVTs in the current BTZ are no longer suitable for developing the current building design. Therefore, the calculation method of bidirectional optimization zone index division standard is established: Forward optimization to obtain the outdoor threshold value that meets the indoor temperature calculation; Reverse optimization to obtain the distribution trend of the combined form of the envelope structure under the known indoor calculated temperature and outdoor climate conditions. According to the new calculation method, the outdoor heating threshold temperatures (OHTT) are adjusted from the original 5 °C–10 °C. In addition, CVTs are updated for significant subregions, such as: 1) the CVT for the hot summer and cold winter and hot summer and warm winter zone is calculated as 10 °C; 2) the CVT for severe cold (SCZ) and cold zones (CZ) is updated to −8 °C. These results will support the development of a BTZ and provide a scientific basis for reforming the heating method in China.

INFLUENCE OF CLIMATE ON THE COUPLED HEAT AND MOISTURE TRANSFER THERMAL CALCULATION IN CHINA

ABSTRACT The climate in China varies substantially across its extensive territory. However, the traditional thermal design of buildings is primarily based on pure heat calculation that considers only heat transfer. Therefore, the heat transfer of a building envelope should be clarified under the action of periodic external disturbance circulation. In this study, four different climatic factors were selected for heat transfer simulation, including season, solar radiation, air temperature, and relative humidity. The results indicate that the outdoor relative humidity has a significant impact on the difference between coupled heat and moisture calculation and pure thermal calculation. This influence becomes evident in the cooling conditions in summer but weakens in the winter heating conditions. Accordingly, the meteorological data of 270 cities in China were statistically analyzed using Python programming language. The concept of “cooling high-humidity days” was proposed as a zoning indicator for coupled heat and humidity thermal calculation zoning. The coupled heat and moisture thermal calculation design zoning map of China is provided, which affords the specific calculation method in building thermal design.

Simultaneous thermal zoning and demand control ventilation

Heating, Ventilation, and Air Conditioning systems play a crucial role in controlling indoor air conditions, including temperature, humidity, and CO₂ concentration, to ensure human comfort and safety. Thermal zoning and demand-controlled ventilation have demonstrated enhancements in comfort and energy efficiency. This study aims to develop a mathematical model for a Heating, Ventilation, and Air Conditioning system employing an estimated state-feedback control algorithm to optimize indoor comfort and energy savings while minimizing sensor requirements. The model encompasses dynamic equations governing CO₂ concentration and temperature in a five-room building. Temperature regulation is achieved by adjusting the airflow from a cooling unit with dampers, while CO₂ levels are managed by controlling the proportion of fresh air intake. To showcase the advantages of the proposed control approach, comparisons were made with alternative methods based on response performance, energy consumption, and sensor requirements. The estimated state-feedback control outperformed other approaches, requiring only one temperature and one CO₂ sensor at the mixed return. Additional occupancy sensors in each room are not necessary if an Extended Kalman filter is utilized. This technique exhibits scalability, adaptable to varying output variables and room configurations, and holds promise for broader implementation in the HVAC industry. By optimizing energy consumption and maintaining indoor air quality, this approach aligns with established sustainability metrics, promoting environmental responsibility. Compliance with health and safety audit standards ensures the fulfillment of social targets, while adherence to regulations and laws ensures governance targets are met.

LCZ framework and landscape metrics: Exploration of urban and peri-urban thermal environment emphasizing 2/3D characteristics

Rapid urbanization has altered the environment and climate, necessitating a thorough grasp of urban thermal dynamics for sustainable development. The lack of detailed urban information poses a considerable challenge. This study employs the Local Climate Zone (LCZ) framework to delve into the intricate relationship between land surface temperature (LST) zones and both 2/3D urban characteristics. The LCZ map for Bojnourd city, Iran, was prepared, consisting of eleven classes categorized into five built types and six land cover types. The mean LST in the summer of 2021 was derived from Landsat8 using the split-window algorithm (SWA) and divided into seven thermal zones. The research reveals distinctive spatial patterns of LCZs across various Land LST zones. Notably, LCZ2 (Compact mid-rise) and LCZ 3 (Compact low-rise), despite differing heights, share the same thermal zone (Zone3), suggesting influences beyond height on thermal zoning. In contrast, LCZ5 (Open midrise), situated in a cooler thermal zone (Zone2), features more vegetation and taller trees, exhibiting a lower LST range compared to LCZ2 and LCZ3. Class-level metrics (AREA_MN and LPI) offer a similar description of LCZ spatial patterns, while landscape-level metrics like SHDI and IJI provide a more insightful depiction of spatial patterns. The study found that the most appropriate spatial pattern for improving urban thermal conditions involves considering a set of factors such as vegetation presence, land cover proximity, height, and density. This ensures sustainable and green urban development that is in tune with climate change and promotes balanced and harmonious thermal patterns in the urban environment.

BIM and Sustainable Design: A Review of Strategies and Tools for Green Building Practices

Building Information Modeling (BIM) provides a robust foundation for driving sustainability across architecture, engineering and construction (AEC) practices. This paper presents a systematic review of literature elucidating the confluence of BIM tools and processes with accelerated performance simulations and green building certification systems needed to guide environmentally sensitive design. Integrated Revit-Insight 360 is shown to enable 21% lower energy use intensity (EUI) and 8.5% reduced lifecycle costs over baseline for an office building through rapid multi-objective optimization spanning orientation, envelope and HVAC properties. Enhanced integrated platforms perform detailed thermal zoning analysis capturing realistic solar gains and heat storage effects, right-sizing heating equipment by 7.2% over conventional workflows. Further, BIM automation mitigates nearly 50-80% of manual calculations for BEAM Plus, LEED prerequisites and accelerates documentation for certification. However, interoperability issues inhibiting holistic sustainability evaluations persist due to lack of modeling standards. Emerging tools exemplify modular green assessment connecting multi-vendor engines to resolve underlying technical barriers. As BIM object definitions and seamless analytical integration matures, widespread mainstreaming for sustainability is foreseeable. While current measured metrics revolve around energy use, emissions and green certification, future work needs to address social and economic indicators also enabled by data-rich BIMs. Nevertheless, coupled with continuous monitoring for validation, BIM provides the foundation for the AEC industry to progress towards comprehensive sustainable building lifecycles.

Environmental Complexes with Thermal Zoning for the Conditions of the Far North and the Arctic

The author’s proposals dedicated to the optimization of the design process, considering the specific requirements determined by the natural and climatic conditions of the Far North and the Arctic zone of the Russian Federation are disclosed. The authors rely on two methodological approaches: optimization of urban planning policy, on the one hand, and revision of the typology of residential and public buildings for the conditions of the Arctic and the Far North, on the other. The authors have developed and are actively promoting the basic principles of “green architecture” (the buffer principle, the community principle, the compensation principle, the principle of nature-likeness and the principle of vertical transfer). The main objective of this article is to put forward, develop and develop the concept of “thermal zoning”, which inherits the productive typological ideas of the Soviet period. It is shown how the scientific developments of the authors are tested in experimental and competitive design. In addition, specific proposals have been put forward to improve the urban development policy of the Arctic and create a new body that will optimize the activities of designers for the sustainable development of the architectural environment of Arctic cities and settlements.

Impact of thermal zone modeling on a small office building with all-electric HVAC systems in hot-humid and cold-humid climates

In code-compliant simulations, the impact of thermal zoning method is significant on building energy use of building systems. However, in practice, thermal zone modeling is often determined by general rules without careful consideration of the specific characteristics of different HVAC systems. Therefore, this study evaluated the impact of thermal zone modeling on all-electric HVAC Systems in hot-humid and cold-humid climates using different levels of usage profiles. The results of this study identify the significant influence of thermal zoning methods on the annual energy use in all-electric HVAC systems depending on usage rates and climate. When different thermal zoning models were used, the amount of energy used differed depending on HVAC system type and zone usage (i.e., PSZ system varied from 4.6% to 8.8% in Houston, TX, and from 4.6% to 20.1% in Chicago, IL). In addition, a significant difference can be found in peak heating demands for selected HVAC systems in buildings located in cold climates (i.e., for winter peak days, the daily load differences of 21.8% to 24.5% in Chicago, IL). The results of this study can be used to improve the accuracy of thermal zone modeling for code compliance that considers different HVAC system types.

An ontology-based framework for automatic building energy modeling with thermal zoning

Building Energy Modeling (BEM) has wide application in building design and operation stages. Developing BEM requires numerous data from multiple sources, and therefore is time consuming and expertise demanding. Building Information Modeling can provide information needed for BEM, but a seamless transfer of BIM to BEM is not available yet. This study proposes an ontology-based automatic framework aimed at integrating multiple data sources and automatically generating BEM models, in which the ontology model could integrate data from weather, building, internal heat gain, and Heating, Ventilation, and Air Conditioning system. We developed a cross-domain and rule-based reasoning method for thermal zoning, and an automatic ontology model to BEM model translation method using instance-based mapping and dynamic data conversion. We demonstrated our approach by developing a BEM model for one floor of a campus building. The results showed that the proposed framework could automatically generate the model that has the potential to reduce the modeling time by over 99% comparing with manual modeling.

How spatio-temporal resolution impacts urban energy calibration

Building Energy Modeling tools help forecast the energy performance of buildings. Urban energy models (UBEMs) emerged as important instruments to analyze the energy performance of buildings aggregated at different spatial resolutions, from the building level to the district level. They heavily rely on available data on geometries and measurements to create accurately calibrated energy models. However, limited research has been conducted to understand the impact of spatial and temporal resolution on the simulation results because of the difficulty of comparing results and not having a standardized procedure to report simulation errors. We review the literature on UBEM validation compared to measured energy data and show the discrepancies in the reporting accuracy. We articulate the need for consistent reporting on model accuracy and introduce a multi-dimensional Level of Detail (LoD) specification for UBEM, including geometry, thermal zoning, and spatio-temporal resolution of the measured data used to calibrate the models. Using a university campus with 70 buildings as an extensive case study, we demonstrate the performance of Bayesian calibration from the building level to the aggregated level. Our results suggest that the accuracy of urban energy prediction with annual temporal resolution can be significantly increased if calibration is performed by using building-level data. However, whenever privacy is a concern, then the data should be provided by aggregating them based on primary use type. Additionally, using monthly data to calibrate uncertain input parameters is not improving the accuracy of the models because the obtained posterior distributions for the selected parameters are not informative for monthly data. To improve this shortcoming, we suggest seasonal calibration, which is computationally costly.

Evaluation of the Impact of Input-Data Resolution on Building-Energy Simulation Accuracy and Computational Load—A Case Study of a Low-Rise Office Building

Building-energy consumption is the primary aim of urban energy consumption, which can aid in optimization of building operation and management techniques, creating sustainable building and built environments. However, modellers’ understanding of the relationship between building-energy modelling (BEM) accuracy and computational load is still qualitative and deprived of accurate quantitative study. Based on a bottom-up engineering methodology, this study aims to quantitatively explore the effects of building-model input data with different resolution accuracies on energy simulation results, including evaluation of computational load. According to the actual parameters of the case-study building, 108 models with varying input resolution levels were developed to estimate hourly energy usage and annual mean ambient temperature. The results demonstrated that with input parameters at low resolution levels, geometric parameters such as exterior windows, interior windows, and shading exhibited significantly lower computational loads, resulting in reduced errors in the final simulation performance, whereas the occupancy schedule, thermal zoning, and HVAC configuration parameters exhibited significant declines in simulation performance and accuracy. This study presents a methodology applicable to the majority of low-rise, rectangular office structures. Future work would concentrate on carrying out comparison tests for different building forms and types while gradually improving the automation of the process to enable use of the appropriate accuracy level in assessing the crucial issue of energy-modelling input.

Analysis of a HVAC zoning control system with an air-to-water heat pump and a ducted fan coil unit in residential buildings

• Thermal zoning control model is presented for hydronic air conditioning systems. • The control system conditions each zone of the building individually. • The control acts over the AWHP set point water temperature and the fan coil fan speed. • A comparison with a non-zoned ducted fan coil and individual fan coils is performed. • High thermal comfort and total energy savings until 40% are achieved in a dwelling. This paper presents an analysis of a thermal zoning system integrated in a Heating, Ventilation and Air-Conditioning (HVAC) system based on an air-to-water heat pump with a ducted fan coil. Zoned systems are based on independently controlling the temperature of each of the zones of a building. When a zone is not occupied or not in demand, the control board sends a control signal to the zone's motorised damper which interrupts the airflow supply to that room. Although this control system is gaining popularity in the residential sector, the results obtained in terms of thermal comfort and energy consumptions are not evident and should be documented. Besides, the control strategy is based on an algorithm that allows acting on the heat pump, setting the set-point temperature, and on the fan-coil, setting the fan speed. Based on this, it is possible to design an algorithm to optimize the performance of the installation ensuring thermal comfort and achieving energy savings. The thermal zoning and the HVAC control system are modelled and simulated in Trnsys17 for the case of study of a residential dwelling, compared with two different configurations: a non-zoned ducted fan coil and individual fan coils. Important benefits are obtained in the evaluation of thermal comfort, with higher values of PPD in all zones. From the point of view of energy consumption, the influence of the thermal zoning on the performance of the heat pump reports important energy savings. Finally, an economic analysis results in payback periods lower than 4.9 years.

Impact of zoning heating and air conditioning control systems in users comfort and energy efficiency in residential buildings

Nowadays, in the residential sector, a widely used Heating, Ventilation and Air Conditioning system is the ducted direct expansion inverter system based on the on/off control of a single zone, which cannot guarantee the thermal comfort in each room of the building. As a solution, the standard EN 15,232 regulates the use of control systems including thermal zoning as a fundamental condition in the energy efficiency in buildings. The zoning system can adapt the equipment working regime to meet the thermal demand in each zone monitoring the air temperature according to users’ preferences ensuring the thermal comfort in each zone. Framed in this goal, in contrast to complex and costly control systems, this paper presents a new zoned control system based on thermostats and motorized dampers in each zone, a control board and a communication gateway which allows the communication between the unit and the control board to set operational parameters as the speed of the fan or the supply air set point temperature.The practical feasibility of this new control system is presented with a thermo-economic comparison analysis with respect the conventional in the context of the Building Research Establishment Environmental Assessment Methodology certification scheme. The model of the zoning system together with implemented control algorithms is developed in TRNSYS17 and the case of study is a residential dwelling in three different Spanish cities. The results show how the thermal zoning control contributes to adapt the thermal energy to each zone in a more efficient way. Moreover, the regulation of the motorized dampers, fan speed and set point temperature of the unit ensures the thermal comfort in all the zones of the building guaranteeing a category B according to the standard regulations. Finally, from the point of view of energy consumption, energy savings from 21 to 42% are obtained, resulting in payback periods of the installation from 3.2 to 4.3 years.

Influence of the thermal сonditions within the bed of the last ice sheet on the distribution of glacial valleys of the Belarusian Poozerie area

Within the bed of the Poozerie (Weichselian) ice sheet, which occupied the northern part of Belarus at the maximum stage and at the beginning of degradation, three concentric thermal zones were identified according to geological and geomorphological criteria: the outer zone of basal frozen ice, the zone of discontinuous frozen bed, the inner zone of the thawed bed. Comparison of glacial valleys with thermal zoning shows that their distribution and formation closely related to thermal conditions. During the Poozerie (Weichselian) ice sheet advance into the northern region of Belarus, thermal zoning affected geological denudation processes. This led to local erosion and valleys in the outer zone of basal frozen ice, large-scale manifestation of glacial excavation and squeesing out and the formation of lobate glacial depressions, large radial valleys and subglacial lakes in the inner zone of the thawed bed and along its outer border with the zone of discontinuous frozen bed. The formation of large tunnel valleys became possible at the stage of degradation of the ice sheet (Vitebsk phase), after the melted glacial waters of subglacial dammed lakes found an outlet into the marginal zone through an intermittent frozen bed and were released as a result of catastrophic floods through separate channels, which were deepened, widened and formed tunnel valleys.

The Impact of Detail, Shadowing and Thermal Zoning Levels on Urban Building Energy Modelling (UBEM) on a District Scale

New modelling tools are required to accelerate the decarbonisation of the building sector. Urban building energy modelling (UBEM) has recently emerged as an attractive paradigm for analysing building energy performance at district and urban scales. The balance between the fidelity and accuracy of created UBEMs is known to be the cornerstone of the model’s applicability. This study aimed to analyse the impact of traditionally implicit modeller choices that can greatly affect the overall UBEM performance, namely, (1) the level of detail (LoD) of the buildings’ geometry; (2) thermal zoning; and (3) the surrounding shadowing environment. The analysis was conducted for two urban areas in Stockholm (Sweden) using MUBES—the newly developed UBEM. It is a bottom-up physics-based open-source tool based on Python and EnergyPlus, allowing for calibration and co-simulation. At the building scale, significant impact was detected for all three factors. At the district scale, smaller effects (<2%) were observed for the level of detail and thermal zoning. However, up to 10% difference may be due to the surrounding shadowing environment, so it is recommended that this is considered when using UBEMs even for district scale analyses. Hence, assumptions embedded in UBEMs and the scale of analysis make a difference.

The Potential of Harnessing Real-Time Occupancy Data for Improving Energy Performance of Activity-Based Workplaces

Currently, the available studies on the prediction of building energy performance and real occupancy data are typically characterized by aggregated and averaged occupancy patterns or large thermal zones of reference. Despite the increasing diffusion of smart energy management systems and the growing availability of longitudinal data regarding occupancy, these two domains rarely inform each other. This research aims at understanding the potential of employing real-time occupancy data to identify better cooling strategies for activity-based-working (ABW)-supportive offices and reduce the overall energy consumption. It presents a case study comparing the energy performance of the office when different resolutions of occupancy and thermal zoning are applied, ranging from the standard energy certification approach to real-time occupancy patterns. For the first time, one year of real-time occupancy data at the desk resolution, captured through computer logs and Bluetooth devices, is used to investigate this issue. Results show that the actual cooling demand is 9% lower than predicted, unveiling the energy-saving potential to be achieved from HVAC systems for non-assigned seating environments. This research demonstrates that harnessing real-time occupancy data for demand-supply cooling management at a fine-grid resolution is an efficient strategy to reduce cooling consumption and increase workers’ comfort. It also emphasizes the need for more data and monitoring campaigns for the definition of more accurate and robust energy management strategies.

A procedure for automating thermal zoning for building energy simulation

Although many previous studies have addressed the accuracy of building energy simulations, very few studies of this subject have mentioned the importance of Heating, Ventilation, and Air-Conditioning (HVAC) thermal zoning strategies to sustainable building design. In addition, the building energy standards and guidelines related to building energy simulation recommend that only a core and perimeter thermal zoning strategy be used to reduce the total number of thermal zones in a model. However, although this simplifies modeling, it can lead to too many thermal zones in the building energy model of a multi-story building, or in some cases too few zones, which can impact the model's accuracy. Therefore, the aim of this study is to develop a new thermal zoning process for building energy simulation called the “grid/cluster method.” that can be applied automatically to whole-building energy simulations of multi-zone commercial structures. To verify this new thermal zoning method, the indoor temperature profiles of grid units were carefully analyzed in a case study simulation. In this study, three thermal zoning simulation models for a rectangular building were created and applied in heating- and cooling-dominant climates. The results show that for both climate conditions, the new grid/cluster method reduced heating/cooling loads by 11%–27% as compared to the single-zone model. In addition, the results significantly improved the simulated indoor comfort conditions.

Solar shading and multi-zone thermal simulation: Parsimonious modelling at urban scale

With the growing interest in urban scale simulation, urban building energy modelling tools (UBEM) are being developed. The purpose of these UBEM tools is to tackle multiple issues that can range from buildings retrofit potential to the sizing of thermal and/or electrical network or to the assessment of renewable energy sources potential. Unlike the modelling of a single building, collecting accurate building information data at district scale is nearly impossible and therefore the uncertainties increase. In this context, the selection of the most relevant and adequate models with regard to the available data and simulation objectives is challenging, and often a trade-off between accuracy and parametrization feasibility has to be found. A novel approach is proposed to choose the right level of model complexity for thermal heating demand simulation in buildings at district or city scale, by assessing in particular the impact of different thermal zoning methods with the UBEM tool DIMOSIM. This method for assessing the parsimony in modelling is applied to a selection of models from the literature in order to find a compromise between the available data, the different modelling levels of detail, the expected output and the computation time, according to district and buildings characteristics. By applying this approach, it has been found that a division per floor for building modelling is in most cases the most parsimonious choice for thermal heating demand simulation at district scale. Eventually, the coupling between thermal zoning models and solar shading models is analysed through the same methodology for assessing the modelling parsimony. The results show that the combination of simpler models (in particular a thermal zone per floor or mono-zone buildings for thermal zoning models, and a solar shading coefficient calculated per floor or facade for solar models) can be parsimonious enough to be used to determine the annual heating demand, speeding up strongly the simulation at the same time.

A clustering-based climatic zoning method for office buildings in China

Since the influence of building types has not taken into consideration, the current climatic zoning scheme of China may not fully reveal the real energy requirements, especially the annual energy consumption variation of different types of buildings. This study proposes a novel zoning method based on the clustering of building thermal load data of a typical office building. Thermal load simulations were performed under 274 cities’ meteorological conditions across China. Two widely used clustering algorithms: K-Means and Agglomerative Hierarchical Clustering were adopted and compared. Based on the inter-city clustering results, a new zoning map with five distinct zones for building thermal design was developed. To demonstrate the thermal load patterns, especially its dynamic characteristics, three representative cities from the three most densely populated zones were selected for intra-city clustering. The results demonstrate that K-Means method performed better in building thermal design zoning and thermal load pattern analysis, and the optimal thermal zone number is 5. The present zoning method could be applied to other building types and promotes an improvement of the existing zoning strategy. It benefits not only architects, but also building operators and policy makers for energy efficiency design and even green urban design.

Reclassification of climatic zones for building thermal regulations based on thermoeconomic analysis: A case study of Turkey

Classification of climatic zones is required for building thermal regulation. In this context, a novel approach based on thermoeconomic analysis is proposed to reclassify climatic zones of Turkey. The classification is carried out by accounting different climatic-built parameters, namely thermal insulation, main wall component, fuel type, as well as heating and cooling degree-days (HDD and CDD). With this aim, 80 provinces of Turkey are reclassified into 5 zones based on fuzzy c-means clustering method regarding 27 different optimum insulation thickness attributes calculated for each city. The results showed that compared to the current national thermal zones, based only on HDD values, 16 out of 80 provinces shift to a new category, all of which correspond to a higher zone indicating the requirement of a thicker insulation layer. The results are presented with membership degrees giving more insight into the climate of analysed cities, discussed in terms of reduction in energy-cost and global greenhouse gas emissions. The obtained new classification revealed that the current national thermal zoning methodology is inadequate in division of the studied geographical area particularly for mild climates where cooling needs are significant. Finally, an updated climate zone map of Turkey for building thermal regulation is proposed.

Thermal zoning and window optimization framework for high-rise buildings

Window sizing and configuration can have a significant influence on building energy consumption. Window selection often has a conflicting objective on heating, cooling, and lighting performance. The smaller window performs better on controlling heat loss in winter and solar heat gain in summer, while the larger window performs better on providing views, daylight, and solar heat gains in winter. Also, the energy consumption analyses of high-rise buildings have some fundamental limitations that include the changes in microclimate parameters with altitude, the treatment of building size, uncertainties associated with the existing convective heat transfer coefficients correlations (CHTC). This study provides a framework for simulation-based optimization of window configuration for a high-rise building to minimize its energy consumption. The technique involves CFD modeling to validate and develop new-CHTCs, a Building Energy Simulation used to assess the energy consumption using the newly developed CHTC, and a numerical optimizer for iterative optimal window configuration selection. The decision parameters are window size and room location. The thermal comfort temperature set points and daylight illuminance are taken as constraints. The proposed approach is implemented as a case study on a single by single room model basis positioned at different heights in an isolated 100 m tall building exposed to Boston, MA microclimate. For a room located on the 2nd, 15th, and 29th floor, an optimum window configuration of 30%, 48%, and 30%, window-to-wall ratio, respectively, are obtained.