Abstract: Heat pumps are an attractive heating system in residential buildings. They operate based on the vapor compression cycle used in refrigeration systems. Design questions surrounding heat pumps can be investigated and answered using modelling tools that incorporate the necessary thermodynamics, fluid mechanics, and machinery component efficiency. Several modelling tools are available, however there is a need for more open-source, script-based programs that are competitive to those already available. This work presents a Python-based code for modeling the thermodynamics of the vapor compression cycle (VCC) in typical heat pumps. The main contribution of this work is an openly available online code, complete with a few examples to show its functionality, that provides the basic thermodynamic model of a heat pump for researchers or development engineers to use, modify, and extend. Its current features include choice of refrigerant, heat exchanger size and characteristics, compressor, and other design parameters such as heating load, and fluid temperatures in and out of the heat exchangers. Simulation outputs include the P-h and T-s diagrams and coefficient of performance (COP). The code is flexible and suggestions for future code development are given.
Permalink: https://doi.org/10.3384/ecp200022

Abstract: Porous pavement is a well-documented, low-impact stormwater management technique. When it comes to design of the top layer, the amount of void space (porosity) is often of interest as it influences both infiltration and strength of the pavement. Laboratory equipment can be used to measure the porosity of core samples, but when more detail is required, other equipment or methods must be used. One such method is to scan the entire sample using a computer tomography (CT) machine and then perform some image processing techniques on the scanned data to reconstruct the sample digitally. While the workflow of scanning and processing to produce the 3D digital twin of porous pavement is not new and can be in fact done by open-source or commercial software, there are still some parts of the process that deserve a deeper investigation, for example binarization and segmentation algorithms applied to the solid-and-void space and void space, respectively. This is difficult to do with commercial software which operates like a black-box, and there needs to be more open-source codes that are user-friendly, extendable, and competitive to what commercial software can do. This work presents a MATLAB-based code that allows for a deeper investigation of how one can accurately and efficiently quantify the effective (or connected) void space of a porous pavement sample from a 3D digital model. We demonstrate the effect of dataset coarsening, which can be used to reduce the computational intensity of the algorithm while preserving accuracy. The code is publicly available online to allow for reproducible research and the possibility of extensions for increased functionality and complexity.
Permalink: https://doi.org/10.3384/ecp200049

Abstract: Radiant floor cooling system as a means of radiant cooling has been well used in engineering. This paper discussed the application potential of the control strategies of radiant floor cooling system in existing research. Based on the principle of anti condensation, the anti condensation strategies of radiant floor cooling system are introduced. In addition, the effects of different weather types on the performance of radiant floor cooling system are summarized. These work will be beneficial to the engineering application and popularization of the control strategies of radiant floor cooling system. Finally, the further research direction of radiant floor cooling system control strategies is proposed.

Abstract: Due to today’s sustainability concerns, we must find ways to decrease, the CO₂ footprint of the products and systems that are used in buildings. The StaticusCare project, funded by EEA/Norway Grants, emerged from this need, since it aims to decrease the greenhouse gas emissions associated to the construction industry by developing a hybrid timber and aluminium based facade system that will integrate IoT sensors. A decrease of the facade’s embodied CO₂ footprint of 70-75 % and of the non-renewable energy consumption to 53-56 % is expected. However, it must be ensured that this system has the necessary quality to be installed in the Nordic climates, even for future conditions. Computational models, both at the assembly level as well as at the building level, will be developed. The first level model will allow to perform thorough hygrothermal analysis of the facade system, whilst the second level model will allow to analyse the effect of the system at the building level, i.e. in terms of energy and indoor environment. In addition, this second level model will also be used to obtain the indoor conditions – i.e. temperature and relative humidity – that the first level model needs as an input to run. In order to make this study more comprehensive and, at the same time, determine how differently the facade system will perform under different climates, several representative Nordic outdoor climates will be used in the simulations. Climate change, by means of outdoor weather files, was considered, as well as the effect of moisture penetrating in the tested facade system due to air infiltration or even using timber with a high moisture content due to unprotected storage. It is determined that the tested system is able to properly dry the excess of moisture under current and future conditions. However, if the timber is not properly protected from moisture, then the situation is completely different.
Permalink: https://doi.org/10.1088/1742-6596/2654/1/012019

Abstract: Development of the method for automated and adaptive assessment of mould growth in the timber frame facade is presented. A heat, air, and moisture (HAM) transport simulation using the open-source Python library HAMOPY is validated against a wellestablished software (WUFI Pro 1D). Climate input of the reference year in Norway, Oslo is used in validation. The material parameters of the 1D numerical model that influence mold growth conditions most are identified via a parametric study. The increased water vapor permeability and thermal conductivity of the outside envelope as well as the critical relative humidity threshold are selected as the model updating parameters to account for the risk of the thermal bridge, moisture leakage, and mold growth conditions variation in the model. The example of the automated parametric computation of the mold growth conditions in the facade is presented for a reference climate based on the developed and validated HAM model.
Permalink: https://doi.org/10.1088/1742-6596/2600/16/162002

Abstract: The accurate prediction of residential heat load is crucial for effective heating system design, energy management, and cost optimization. In order to further improve the prediction accuracy of the model, this study introduced principal component analysis (PCA), the minimum sum of squares of the combined prediction errors (minSSE), genetic algorithm (GA), and firefly algorithm (FA) into back propagation (BP) and ELMAN neural networks, and established three kinds of combined prediction models. The proposed methodologies are evaluated using real-world data collected from residential buildings over a period of one year. The obtained results of the PCA-BP-ELMAN, FA-ELMAN, and GA-BP models are compared with the neural network before optimization. The experimental results show that the combined prediction models have higher prediction accuracy. The Mean Absolute Percentage Error (MAPE) evaluation indices of the three combined models are distributed between 5.95% and 7.05%. The FA-ELMAN model is the combination model with the highest prediction accuracy, and its MAPE is 5.95%, which is 2.25% lower than the MAPE of an individual neural network. This research contributes to the field by providing a comprehensive and effective framework for residential heat load prediction, which can be valuable for building energy management and optimization.
Permalink: https://doi.org/10.3390/buildings13092340

Abstract: Ventilation, air filtration and disinfection have been found to be the main engineering measures to control the airborne respiratory infection transmission in shared indoor spaces. Wells-Riley model modifications allow to calculate the infection risk probability, but gaps in viral load data, risk control methods and dealing with incomplete mixing have resulted in ventilation recommendations falling short to consider activity and room specific viral loads and actual air distribution systems deviating from fully mixing. In this study a new infection risk-based ventilation design method operating with space category specific target ventilation rates and point source ventilation effectiveness is proposed. The method introduces the following novelties: i) explicit target ventilation rate equations depending on number of occupants and room volume derived for selected room categories ii) implementation of pre-symptomatic period infection risk control iii) point source ventilation effectiveness application to calculate the design ventilation rate for actual air distribution system iv) ventilation effectiveness measurement method with at least two point source locations developed and tested with laboratory and field measurements. Results show that in classrooms and offices existing Category I ventilation is enough in many cases, but higher ventilation is needed in meeting rooms, restaurants, and gyms where also occupancy reduction and advanced air distribution can be considered for feasible ventilation design.
Permalink: https://doi.org/10.1016/j.enbuild.2023.113386

Abstract: This paper investigates a hybrid ventilation control method for a mixed-mode office landscape in a cold climate, i.e. Norway. The mixed-mode building utilizes a hybrid ventilation system that combines natural ventilation through automatic window opening with a balanced mechanical ventilation system controlled by demand control ventilation (DCV) method. For natural ventilation, the windows consist of two parts: the upper part which is openable and the lower part that is not openable and equipped with external solar shading. From a control point of view, the article elaborates a control algorithm for the proposed hybrid ventilation based on various parameters including outdoor air temperature, indoor air temperature, CO₂ level, maximum air change per hour (ACH), operation schedules, and heating/cooling setpoints. The simulation results obtained from the hybrid ventilation and mechanical ventilation cases are compared based on thermal comfort, CO₂ level, and energy savings. The primary results show that the proposed hybrid ventilation control method can satisfy the thermal comfort and CO₂ level requirements while reducing the energy use for fan and ventilation cooling by approximately 55% and 45%, respectively. While the impact on energy consumption for space and ventilation heating is negligible.
Permalink: https://doi.org/10.1088/1742-6596/2600/10/102006

Abstract: To upgrade the computational efficiency and ensure the accuracy of calculated cooling capacity of radiant cooling floor, this study proposed a simplified three-dimensional modeling by combining with a user-defined function compilation. The cooling capacity and minimum floor temperature were taken as evaluation indices considering different radiant floor thicknesses, layers’ thermal conductivities, pipe diameters, pipe spacing, and floor surface sizes. Moreover, a backpropagation neural network model and a prediction program were developed to quickly predict minimum floor temperature and cooling capacity. The results demonstrate that the established backpropagation neural network model can predict the values of cooling capacity and minimum floor temperature well, and the coefficients of determination were 0.9117 and 0.9435, respectively. With the thickness increase of cover layer and filling layer, the minimum floor temperature respectively increases by 10.97% and 11.01%. With the heat transfer coefficient increase of cover layer and filling layer, cooling capacity respectively increases by 30.56% and 23.46%. This study proposes an artificial intelligence method for the rapid prediction of cooling capacity and minimum floor temperature, and provides their theoretical support for engineering application.
Permalink: https://doi.org/10.1080/13467581.2023.2244730

Abstract: This paper describes a multistep approach that allows the design and assessment a hybrid, timber-based, facade system that can withstand current real conditions without being prone to mould. This approach is aligned with today’s drive for a more sustainable built environment. A typical office building with the hybrid system was simulated in a BES tool to obtain the indoor conditions in three selected locations in Norway. Historic measured weather data were used to build climate files, in accordance with ISO 15927-4 methodology. The global radiation was split using the DIRINT model, while a user-independent code was developed to find and fill the weather datasets gaps. A model was built using a one-dimensional HAM software for each facade section to assess its hygrothermal performance, whose studies are scarce in literature, and determine whether the system is appropriate for Nordic climate. This analysis included mould growth risk assessment, determining the variance of the transient U-values and the influence of the wood surface treatment on the drying capacity of the facade. The obtained energy consumptions are in accordance with the current Norwegian regulations. Under normal conditions, the system works properly. However, problems arise if a higher initial moisture content exists in the materials.
Permalink: https://doi.org/10.1016/j.enbuild.2023.113368

Abstract: Materials production dominates the total Greenhouse gas (GHG) emissions in the construction industry. On the other hand, most existing building stocks are expected to last for the next 30 years, which can contribute to increasing resource efficiency, reducing environmental impact, and creating social, cultural, and economic values for society. Therefore, it becomes vital to investigate the environmental impacts of adaptive reuse of existing buildings using a life cycle approach. The objective of this study is to explore the environmental performance of adaptive reuse of an industrial heritage building compared to new construction using a life cycle assessment (LCA) method. The environmental impacts of the selected case study are evaluated using four scenarios, with two adaptive reuse scenarios, a warehouse or an office building and two new construction scenarios, a new warehouse or a new office building. One-Click LCA is used as an LCA tool, and the scenarios are compared by total carbon footprint, life cycle models, GHG emissions per building elements and material types. The results show that among the four scenarios, the adaptive to warehouse scenario is the best adaptation option with considerably lower environmental impact, followed by the adaptive office scenario. This paper highlights that adaptation of existing industrial heritage buildings, with the least materials replacement option, is worthwhile. The further evaluation needed for the study’s limitation is also highlighted for data efficiency and potential for further research. Keywords: Adaptation reuse; Case study; Circular economy; Industrial heritage building; Life cycle assessment; Norway.
Permalink: https://doi.org/10.1088/1755-1315/1196/1/012107

Abstract: The high price of purpose-made turbines always represents an active challenge when utilizing pico- and micro-hydropower resources. Pumps as turbines (PATs) are a promising option to solve the problem. However, the selection of a suitable pump for a specific site and estimating its performance in the reverse mode are both major problems in the field. Therefore, this paper aims to develop generic mathematical correlations between the site and the pump hydraulic data, which can be used to select the optimal operation of the pump as a turbine. A statistical model and the Pearson correlation coefficient formula were employed to generate correlations between the flow rate and the head of the pumps with the sites. Then, Ansys CFX, coupled with SST k-ω and standard k-ε turbulence models, was used to analyze the performance of the PAT. The analysis was conducted in terms of flow rate, pressure head, efficiency, and power output. The numerical results were validated using an experimental test rig. The deviations of the proposed correlations from the statistical model were found to be in the range of −0.2% and 1.5% for the flow rate and ±3.3% for the pressure head. The obtained numerical outputs using the standard k-ε turbulence model strongly agreed with the experimental results, with variations of −1.82%, 2.94%, 2.88%, and 1.76% for the flow rate, head, power, and efficiency, respectively. The shear stress transport (SST) k-ω turbulence model showed relatively higher deviations when compared to standard k-ε. From the results, it can be concluded that the developed mathematical correlations significantly contribute to selecting the optimal operation of the pump for power-generating applications. The adopted numerical procedure, selected mesh type, turbulence model, and physics setup provided good agreement with the test result. Among the two turbulence models, the standard k-ε performs better in estimating the pressure head, output power, and efficiency of the PAT with less than 3% errors when compared to experimental results.
Permalink: https://doi.org/10.3390/en16135036

Abstract: To prevent respiratory infections between patients and medical workers, the transmission risk of airborne pollutants in hospital wards must be mitigated. The ventilation modes, which are regarded as an important strategy to minimize the infection risk, are challenging to be systematically designed. Studies have considered the effect of ventilation openings (inlets/outlets) or infected source locations on the airflow distribution, pollutant removal, and infection risk mitigation. However, the relationship (such as relative distance) between ventilation openings and infected sources is critical because it affects the direct exhaust of exhaled pollutants, which has not been thoroughly studied. To explore pollutant removal and infection prevention in wards, different ventilation modes (with varying ventilation openings) and infected patient locations must be jointly considered. This study investigated displacement ventilation (DV), downward ventilation (DWV), and stratum ventilation (SV) with 4, 6, and 10 scenarios of ventilation openings, respectively. The optimal ventilation mode and relative distance between outlets and infected patients were analyzed based on the simulated pollutant concentration fields and the evaluated infection risk. The pollutant removal effect and infection risk mitigation of SV in the ward were largely improved by 75% and 59% compared with DV and DWV, respectively. The average infection risk was reduced below 7% when a non-dimensional relative distance (a ratio of the actual distance to the cubic root of the ward volume) was less than 0.25 between outlets and infected patient. This study can serve as a guide for the systematic ventilation system design in hospitals during the epidemic.
Permalink: https://doi.org/10.1016/j.envpol.2023.122025

Abstract: A main goal of the study is to investigate whether decentralized ventilation (DV) systems can outperform typically centralized ventilation (CV) system in terms of energy while keeping indoor air quality at acceptable levels. And additional research questions regarded heat recovery function and placement of DV units within the apartment space. The question about modeling the DV units themselves within a Software, IDA-ICE was investigated. The placement of DV unit has been proposed. The advantages and drawbacks of using such systems were outlined and compared to centralized ventilation. The question of modeling DV units in building simulation software was raised and discussed. Results show that, given the chosen set of boundary conditions and model of DV, it offers the best performance energy-wise in the mild season. The differences are most visible during colder months when the heat demand is highest. A DV came out with slightly worse energy performance with low heat recovery unit (HRU) performance. The differences weren’t substantial and none of the analyzed systems met the TEK17 requirement for net delivered energy for residential buildings. No significant difference was shown regarding indoor climate indicators across systems. Seasonal energy analysis shows marginal differences between systems. HRU function showed significant energy-saving potential in cold seasons.
Permalink: https://doi.org/10.1051/e3sconf/202339603001

Abstract: In the world of cultural heritage, a wide range of artefacts and buildings are made of wood and, therefore, are subjected to moisture-induced stress and strain cycles, owing to environmental fluctuations. Simultaneous action of moisture and mechanical loads lead to a mechanosorptive effect on wood. Therefore, an increase in time-dependent creep, due to mechanical loads, is observed. The assessment of these complex phenomena entails the use of advance and interdisciplinary approaches. Consequently, this article reviews experimental and mathematical methods to study these degradation mechanisms in wooden artefacts and timber elements in heritage buildings. The paper presents the results of a six-step descriptive literature review, providing an overall picture of the ongoing research. Experimental techniques need to be improved so that they are in line with the conservation principles. The combination of experiments and simulations is a reliable predictive approach for better assessing the potential risk damages due to temperature, humidity cycles, and mechanical loads in complex structures. Thus, advanced numerical simulations and mathematical modelling include climate data and experimental measurements. This work also provides an overview of research performed on different categories of cultural heritage characterised by multi-layer structures. The mechanical response to wood–moisture relation is affected by the level of complexity of these structures. Finally, the use of realistic models is limited by knowledge about the material properties and the behaviour of complex structures over time. In addition, research gaps, limitations, and possible future research directions are also provided. This review may represent a starting point for future research on the thermo-hygro-mechanical behaviour of wood heritage.
Permalink: https://doi.org/10.3390/app13127251

Abstract: Norsk Folkemuseum, the Norwegian Museum of Cultural History, plans to build a centre for traditional wood crafts and building customs, TradLab TRE. TradLab will be built as a modern and traditional building with the reuse of the materials of old barns. A desire to use these materials for the load-bearing system and in the new buildings demands careful dismantling of the barn building. The Norwegian Museum of Cultural History requires the design and execution of special solutions by the design team and executors. The goal is to integrate as much old timber as possible in the new building and to add new timber where it is needed. The project also wants to reuse cladding and find more ways to use the material in the new buildings, such as in the floor surface or climate walls. By using the craftmanship skills to integrate the traditional knowledge into the design of the building, the overall goal is to investigate the actual efficiency of tradition.
Permalink: https://doi.org/10.52202/069179-0581

Abstract: The objective of the study was to determine the influence of wood coatings for CLT on the moisture buffering capacity and the indoor environment regarding relative humidity and heating demand. Based on the results of a previous screening of a wide range of coatings, three commercial products were chosen: a flooring oil, an alkyd-based interior wall stain and a fire-retardant stain that were considered to provide both, i) high water vapor permeability to maintain wood’s hygroscopicity, and ii) adequate protection of CLT under storage, transport, installation and service. A climate chamber test revealed a good moisture buffer capacity of untreated CLT and a limited one of CLT cladded with gypsum. CLT’s glue lines in the frontal plane were not found to affect moisture dynamics. The flooring oil and the wall stain reduced the practical moisture buffer value by 39% and 10%, respectively, as compared to the uncoated CLT. CLT coated with the fire-retardant stain had an even higher practical moisture buffer value than uncoated wood, which is explained by the stain’s pronounced hygroscopicity. In all elements tested in a heat flux experiment, the theoretical Uvalues were higher than the experimentally obtained and simulated values. Hygrothermal energy simulations using a room of 50 m2 as ‘reference model’ showed that wood’s moisture buffer capacity is beneficial for the indoor environment, by means of passive regulation of RH and lower energy demand for humidification and dehumidification.
Permalink: https://doi.org/10.52202/069179-0056

Abstract: This study is part of the European research and innovation project Build in Wood and has investigated the hygrothermal performance of nature-based insulation materials in two timber-based wall systems: i) stud wall and ii) externally insulated cross-laminated timber (CLT). Six nature-based insulation materials were selected for the analyses. The analyses conducted have focused on optimization of exterior wall configurations to avoid moisture-related problems, i.e. interstitial condensation and mould growth, in the wall constructions under various climates in Europe. For this purpose, three European locations representing respective geographical parts of Europe and corresponding climate zones, were selected as input for the simulations: Oslo (Northern Europe), Paris (Central Europe), and Barcelona (South Europe), while different exterior and interior claddings were considered. A commercial 1D hygrothermal software, i.e. WUFI Pro 1D, was used for the computation of the hygrothermal performance of the wall systems, while the add-on software WUFI Bio has been further employed for the detailed evaluation of the risk for biodegradation. In total 684 numerical simulations were conducted. The results show the various insulating materials behave differently when integrated in timber-based system. Generally speaking, both wall systems, i.e. stud wall and CLT, function similarly in Oslo, while in Barcelona the CLT was systems show better performance. The climate of Paris is critical for most of the wall configurations. Furthermore, the existence of ventilated air cavity back from the exterior cladding has a positive effect on all assembly configurations, while the high water vapour diffusion resistance of the exterior cladding might be determinant, in a negative way, for the moisture problems in nature-based insulating materials.
Permalink: https://doi.org/10.52202/069179-0499

Abstract: The increasing demand for temporary housing in many developing countries necessitate the use of sustainable and affordable construction options. Earthbag units have the potential to be integrated into such housings as they are inexpensive, sustainable, and straightforward material options for building structures. Nevertheless, due to their thermal characteristics, earthbag units cannot provide a thermally comfortable environment. Thus, the present study focuses on developing an environmentally and sustainable earthbag unit integrated with phase change materials (PCM) to convert severely harsh indoor spaces to moderately harsh ones. For the design and development of earthbag blocks, several units are developed with varying amounts of PCM encapsulated in expanded perlite (EP) and expanded graphite (EG) within each unit, including block A (reference), Block B (PCM 2.2% of sample weight), C (4.3%), and D (6.5%). An experimental study is then conducted to understand the microstructural properties of the embedded PCM composite in soil. Following this initial study, practical differential techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), thermal conductivity, and Oozing circle test, have been employed over the developed units to measure their thermal characteristics. Test results from DSC and TGA show good thermal stability of PCM and PCM composites, while SEM results indicated that PCM is well distributed within the pores of EP at 50%EP of the PCM weight. The study found the average indoor surface temperatures by block B, block C, and block D to drop compared to the reference block about 1.2 °C, 3.3 °C and 4.1 °C respectively. This clearly shows the benefit of integrating phase change materials in an earthbag unit.
Permalink: https://doi.org/10.1016/j.enbuild.2023.112852

Abstract: This study introduces a Bayesian network model to evaluate the comfort levels of occupants of two non-residential Norwegian buildings based on data collected from satisfaction surveys and building performance parameters. A Digital Twin approach is proposed to integrate building information modeling (BIM) with real-time sensor data, occupant feedback, and a probabilistic model of occupant comfort to detect and predict HVAC issues that may impact comfort. The study also uses 200000 points as historical data of various sensors to understand the previous building systems’ behavior. The study also presents new methods for using BIM as a visualization platform and for predictive maintenance to identify and address problems in the HVAC system. For predictive maintenance, nine machine learning algorithms were evaluated using metrics such as ROC, accuracy, F1-score, precision, and recall, where Extreme Gradient Boosting (XGB) was the best algorithm for prediction. XGB is on average 2.5% more accurate than Multi-Layer Perceptron (MLP), and up to 5% more accurate than the other models. Random Forest is around 96% faster than XGBoost while being relatively easier to implement. The paper introduces a novel method that utilizes several standards to determine the remaining useful life of HVAC, leading to a potential increase in its lifetime by at least 10% and resulting in significant cost savings. The result shows that the most important factors that affect occupant comfort are poor air quality, lack of natural light, and uncomfortable temperature. To address the challenge of applying these methods to a wide range of buildings, the study proposes a framework using ontology graphs to integrate data from different systems, including FM, CMMS, BMS, and BIM. This study’s results provide insight into the factors that influence occupant comfort, help to expedite identifying equipment malfunctions and point towards potential solutions, leading to more sustainable and energy-efficient buildings.
Permalink: https://doi.org/10.1016/j.enbuild.2023.112992

Abstract: Bridges play a crucial role in modern societies, regardless of their culture, geographical location, or economic development. The safest, most economical, and most resilient bridges are those that are well managed and maintained. Recently, climate change has been posed as one of the greatest concerns for the health of bridges. Although the uncertainty associated with the magnitude of the change is large, the fact that our climate is changing is unequivocal. As a result, making bridges resilient to climate change is a priority for the authorities. A well-planned early intervention may save lives and money. Until now, the focus of scientific research has mostly been on the climate science, but any practical plan for the adaptation of bridges has to be rooted in other disciplines, including physics, chemistry, engineering, economics, and finance. Therefore, the goal of this paper is to review the work already done from climate change to bridges and set a roadmap for an integrated assessment approach to the adaptation of bridges to climate change. This approach is grounded in a probabilistic- and physics-based framework able to prioritize bridge adaptation measures as a function of bridge location, climate scenario, impact, vulnerability, risk, and cost in order to assist the authorities in the decision-making process. Because adaptation to climate change is highly context-specific, this approach is mainly focused on concrete bridges. Structural health monitoring technology is proposed as a mechanism for assessing and continuously evaluating the structural condition of bridges and for triggering adaptation measures as a function of the predicted severity of climate change.
Permalink: https://doi.org/10.1061/JBENF2.BEENG-5735

Abstract: Historic masonry buildings are an integral part of human cultural heritage, and they need to be preserved for future generations. Brick is susceptible to frost damage which is common in regions with cold and humid climates. The frost damage on the masonry walls is accumulated over the years becoming more and more critical for the integrity of the historic buildings and it is also affected by climate change (CC). In the current research, the focus was placed on a coastal region in southern Norway with a significant number of historic masonry buildings. The frost damage risk of the masonry walls was assessed by using data from a climate reanalysis for the present conditions and from a climate model under past, present, and future conditions. Two climate-based (CB) indices accounting for the air temperature and one material response-based (MRB) index considering the temperature and moisture content inside a simulated masonry wall were used for the frost damage risk assessment. The inputs for the MRB index were calculated by heat, air, and moisture (HAM) transfer simulations. Within the HAM simulations, the indoor climate was in one case representative of an unconditioned building with air leakages and many openings, while in the second case it was representative of a small, conditioned room. The overall impact of CC was a decrease in the frost damage risk of the masonry walls. However, an increased frost damage risk was observed from the present to the future conditions according to the MRB index for the walls of small, conditioned rooms with higher driving rain load and lower solar radiation gains. The (i) number of freezethaw events, (ii) periods during which freeze-thaw events occur, and (iii) CC-related trends varied based on the considered index with the most explicit risk assessment being the MRB one. Moreover, the freeze-thaw events experienced by the masonry walls of unconditioned, leaky buildings were 20 times more than the ones for the small, conditioned rooms. Significant differences were observed between the results from the climate model and the climate reanalysis which were mainly linked to the underestimation of the air temperature and the overestimation of the precipitation by the climate model. The outputs of the MRB index were translated into certain damage categories while suggestions on improving the limitations of the current research were made.
Permalink: https://doi.org/10.5194/adgeo-58-157-2023

Abstract: The use of chemical scale inhibitors in the oil and gas industry for subsea installations has been presented for a long time, but the ever-increasing exploration of HPHT (high pressure high temperature) wells put demands on knowledge of how the rheological properties such as viscosity of scale inhibitors behave under large pressures. This work reports new experimental data of high-pressure viscosity using a rotational rheometer, measured across a pressure range of 0.1 MPa to 15 MPa, at temperatures from 273 K to 298 K, and a broad range of shear rates, 100 s−1 to 1000 s−1 for a scale inhibitor. The experimental data are used to construct a power-law regression model with ftting parameters. Results indicate that the inhibitor shows a near Newtonian behavior.
Permalink: https://doi.org/10.1007/s10765-023-03165-7

Abstract: Development of a simplified building model can effectively mimic the transient building thermal behaviour which essentially depends on the weather profile and the building architecture under various operational strategies and occupant behaviour. This work presents the mathematical solution procedure based on the white-box physical building thermal model using resistance and capacitance network (i.e. lumped capacitance). The work takes into account the dynamic behaviour of radiator, and its heat flow adjustment via a thermostatic radiator valve, the solar heat gain (function of the time and location), the infiltration heat loss together with building model having multi-zone with multi-layer wall structure. The case study reveals that the integrated behaviour of the building components under a given control strategy paves the way for simulating different control strategies when large-scale district heating systems are considered.
Permalink: https://doi.org/10.1016/j.jobe.2023.106038

Abstract: This research investigated the exergy enhancement performance of a hybrid radiant cooling system adapting to a hot and humid summer conditions through comparative case studies and analyses. This study suggested three cooling systems: a general all-air system (AAS), a conventional radiant cooling system (CRCS), and a hybrid radiant cooling system (HRCS). As a case study, an office building with cooling systems was examined in the summer season in four different cities: Beijing, Shanghai, Chengdu, and Guangzhou, China. This study utilized the building energy performance simulation program to analyze the cooling loads of office space in a building with numerical approaches. The comparison analysis using the four different weather datasets showed simple and rational exergy efficiency and the overall impact ratio. According to the results, the ambient conditions, i.e., the surrounding temperature and the humidity ratio, significantly impacted the cooling systems’ exergy efficiency ratio. On the basis of the calculated energetic and exergetic performance, the HRCS had a higher exergy efficiency and a higher overall impact ratio. The HRCS system released an additional 20–30% of cooling output, and it could adapt well in extreme hot and humid weather conditions compared to the AAS and the CRCS system. The overall cooling impact ratio of the HRCS with an airbox convector was approximately 185% higher than that of the AAS and 8.5% higher than that of the CRCS. This study can provide the design references for the hybrid radiant cooling system and other cooling systems in hot and humid summer conditions.
Permalink: https://doi.org/10.3390/buildings13020465

Abstract: The energy-saving measures and suitable operation parameters will be urgent concerns in future global climate change conditions. However, a critical review revealed that most studies considered upgrading the wall insulation and glazing in the design process or the retrofit stage for existing buildings built before the twenty-first century and neglected improving system energy efficiency and operation of newly retrofitted buildings with higher-performance envelopes in the context of the carbon peak and carbon neutrality. Therefore, a real and newly retrofitted office building in Chengdu was investigated. The effect of indoor cooling and heating temperature setpoints, water supply/return temperature setpoints for the air-conditioning system, night ventilation settings in summer, and renewable energy variables (photovoltaic) are considered in the optimization. The simulation model was validated using the monitored heating and cooling energy consumption. Transient system simulation coupled with jEPlus + an evolutionary algorithm and the non-dominated sorting genetic algorithm were used to explore the optimal solution to reduce carbon emission and energy consumption while ensuring acceptable indoor thermal comfort. The sensitivity analysis showed night ventilation duration and the air change rate had significant effects on carbon emission reduction. The annual carbon emission reduction of the building was 46500–58500 kg from 2030 to 2060 using a photovoltaic panel area of 1000 m2 . The indoor temperature setpoint decreased over time due to the increasing outdoor temperature in the future. Moreover, the building energy system showed a better performance when the air source heat pump cooling setpoint was increased from 7 °C to 9 °C. Decreasing the air source heat pump heating setpoint from 45 °C to 42.5 °C for 2030 and 2060, and from 45 °C to 40 °C for 2040 and 2050 were the optimal solutions. The proposed approach provides guidance for operators to optimize energy savings and operation parameters under future climate conditions.
Permalink: https://doi.org/10.1016/j.egyr.2023.01.049

Abstract: The application potential of radiant floor cooling systems is affected by climatic conditions. The meteorological parameters of 22 cities in five climatic zones in China (severe cold (SC), cold, hot summer and cold winter (HSCW), hot summer and warm winter (HSWW), and temperate) are analyzed to evaluate the applicability of four conventional control strategies of radiant floor cooling system in office buildings. The control strategies are modeled in the Transient System Simulation Program (TRNSYS), and the indoor thermal comfort, condensation risk, energy consumption, and carbon emissions are analyzed. Multi criteria decision-making is used to evaluate the radiant floor system. The results show that the control strategy with direct ground cooling produces the highest energy savings in the five climate zones. The energy savings are 25–66 % higher than those of the three control strategies using a heat pump as a cold source. Under the same indoor environment conditions, the three-step control strategy provides the optimum indoor temperature and humidity control. The number of hours when the three-step control strategy exceeds the thermal comfort zone is 5 % in 22 cities, and the number of hours with condensation risk is only 3%. The variable water supply temperature control and precooling control have better performance than the other strategies in the SC, cold, and temperate zones. In addition, the control strategies are ranked based on their application potential in 22 cities. The application potential of the radiant floor cooling system with a direct ground cooling source is the highest in the five climate zones in the two scenarios with equal weights of the four criteria and is preferable due to less carbon emissions. When the condensation risk is considered, the radiant floor cooling system with a direct ground cooling source exhibits better performance in the SC and cold zones. The variable water supply temperature control is the optimum strategy in the HSCW, HSWW, and temperate zones. The precooling control strategy ranks the highest in Changchun and Guiyang, and the three-step control strategy performs the best in Shanghai.
Permalink: https://doi.org/10.1016/j.enbuild.2023.112772