Comfortable Indoor Environment Research Articles

Multi-objective optimization of heating operation of stratum ventilation under different clothing insulations using Taguchi method, RSM, and SPA-TOPSIS

Stratum ventilation (SV) for heating can provides a comfortable indoor environment, good intake air quality, and energy efficiency when operated correctly. The studies that have been conducted have focused on the operations of SV that occupants’ clothing insulation was set to a fixed value (i.e., clothing insulation of cooling season and heating season is 0.5 clo and 1 clo, respectively), with little attention to different clothing insulations. This study aimed to access the optimal ventilation parameters (i.e., supply air velocity, supply vane angle, and supply air temperature) to satisfy the requirements of thermal comfort for occupants with different clothing insulations, whilst improving indoor air quality and achieving energy savings. Firstly, based on experimentally validated Computational Fluid Dynamics (CFD) simulations, the Taguchi method was used to analyze the effects of operation parameters (i.e., supply vane angle, supply air velocity, supply air temperature, and outdoor air temperature) on the thermal comfort of occupants with different clothing insulations. The results show that the operation parameters affected the thermal comfort of occupants with different clothing insulations inconsistently. Then, taking clothing insulation as one of the important influencing factors in the optimization process, the multi-objective optimization of stratum ventilation for heating conditions was performed by a sequential preference technique based on the set pair analysis method (SPA-TOPSIS) of similarity to the ideal solution. To reduce the costs of computational, response surface models (RSMs) of ventilation performance was formulated and then used to assess the ventilation performance for all operations optimized by SPA-TOPSIS. The results showed that the dynamical optimization of ventilation parameters significantly improves ventilation performance considering different clothing insulations.

Smart Building Management System (SBMS) for Commercial Buildings—Key Attributes and Usage Intentions from Building Professionals’ Perspective

Smart buildings conserve energy and create a responsive, comfortable, and productive indoor environment for users and occupants. As a crucial component of smart buildings, smart building management system (SBMS) should provide a wide range of functions and bring about the intended benefits upon successful deployment. This paper identifies salient SBMS attributes and explores key factors influencing building professionals’ intention to use the system in commercial buildings. Responses were collected from 327 Hong Kong building professionals. Data were analyzed by exploratory factor analysis and structural equation modeling based on the refined Unified Theory of Acceptance and Use of Technology (UTAUT). Exploratory factor analysis shows that intelligent building operations and safety and recovery readiness are two dimensions of SBMS emerged. Specifically, intelligent building operations include intelligent and optimal scheduling of building systems, monitor and control of building facilities, having an intelligent and interactive interface, and enabling alarm settings and automatic notifications, showing the importance on the application of electrical engineering in smart building management. Structural equation model (SEM) results indicate that facilitating conditions affect habit, hedonic motivation, social influence, performance expectancy and effort expectancy. Additionally, habit, hedonic motivation and effort expectancy significantly affect building professionals’ intention to use SBMS. Practical implications of SBMS attributes for energy management and the ways in which SBMS is encouraged to be used by building professionals are given.

The effect of doped glazing on thermal comfort: A case study of solar decathlon Africa

This work is devoted to the study of the optimization of the energy performance of a modern architectural building with large glass surfaces. Within the framework of this study, we were led to use intelligent glazing. It was decided that the glass surfaces would be covered with a tungsten (W)-doped vanadium dioxide (VO2) film. This film is characterized by a phase transition, allowing its transmission coefficient to be high at low temperatures and low at high temperatures. An optimization study of the influence of the doping on the transfer coefficient of the glazing allowed us to obtain a significant improvement in the comfort conditions of the studied building. The results of our study indicate that the VO2/W film coating has a great potential to increase the comfort conditions in buildings, both in winter and in summer. This is because the film can modulate the solar radiation from the outside and thus maintain an ideal temperature inside without the need for an energy-consuming air conditioning system. As a result, VO2/W cladding film offers buildings significant thermal benefits and improved energy efficiency, but also a better quality of life as it provides a comfortable and pleasant indoor environment.

Energy Balance Data-Based Optimization of Louver Installation Angles for Different Regions in Korea

A louver is a traditional environmental control device and passive architectural element based on an ecofriendly concept. Louvers are architectural elements that can be used to regulate natural lighting, thermal environment, and building energy use. To realize these integrated functionalities of louvers, they must be designed considering the climate and geographical characteristics of the target region. However, these aspects are typically not considered during building design in Korea, resulting in lovers being used as design elements with simple natural lighting control functions. Therefore, the objective of this study was to promote the integrated use of louvers by optimizing the louver angle according to the microclimate in Korea from the viewpoint of thermal energy use. We performed load and energy simulation planning and calculation and conducted optimization studies for the louver angle and range of motion for each region. The energy consumption in central and southern Korean regions was minimized when the angles of the fixed louvers were 45°–75° and 60°–90°, respectively. Kinetic louvers could enhance thermal energy management when installed at 30°–75° in spring, 135°–165° in summer, 75°–165° in autumn, and 45°–75° in winter. These findings can promote the realization of integrated functionalities of louvers from the perspective of indoor environment comfort based on the microclimates of the Korean regions.

Comparative Analysis between different types of Responsive Design Approach: (Applicability to Use in Different Climatic Regions in Egypt)

Building and environment integration are necessary to be enabled, and advanced systems must work together to deliver optimal performance in terms of energy comfort and health. Above all, the area where building technology and services overlap, i.e. responsive building components, has great potential to realize the next step in energy efficiency by realizing comfortable indoor and outdoor environments in unprecedented ways. Recent studies have shown that an important reason for introducing new methods as population density increases is to reduce environmental damage. Energy consumption in the built environment accounts for approximately 40% of final energy consumption. In addition, external factors that affect building performance are analyzed, such s Overall building impact, energy consumption, pollution, and climate change. To achieve sustainability, it is proposed to use and implement the latest in smart materials and responsive system technology. The results of the dynamic thermal behavior analyze performed in the Building Concepts building simulation tool are then translated into energy, sustainability, and cost performance indicators, allowing the user to generate information based on the most relevant factors. This paper, therefore sheds light on new design and construction methods that enable buildings to interact with their external environment and achieve architectural responses to surrounding variables. This study aims to clarify the importance of responsive architecture to improve the built environment and the appropriate type of envelope based on climate data, applicable to different climatic regions of Egypt. The results confirm that implementing responsive envelopes has a positive impact on improving performance.

Energy-efficient virtual sensor-based deep reinforcement learning control of indoor CO2 in a kindergarten

High concentrations of indoor CO2 pose severe health risks to building occupants. Often, mechanical equipment is used to provide sufficient ventilation as a remedy to high indoor CO2 concentrations. However, such equipment consumes large amounts of energy, substantially increasing building energy consumption. In the end, the issue becomes an optimization problem that revolves around maintaining CO2 levels below a certain threshold while utilizing the minimum amount of energy possible. To that end, we propose an intelligent approach that consists of a supervised learning-based virtual sensor that interacts with a deep reinforcement learning (DRL)-based control to efficiently control indoor CO2 while utilizing the minimum amount of energy possible. The data used to train and test the DRL agent is based on a 3-month field experiment conducted at a kindergarten equipped with a heat recovery ventilator. The results show that, unlike the manual control initially employed at the kindergarten, the DRL agent could always maintain the CO2 concentrations below sufficient levels. Furthermore, a 58% reduction in the energy consumption of the ventilator under the DRL control compared to the manual control was estimated. The demonstrated approach illustrates the potential leveraging of Internet of Things and machine learning algorithms to create comfortable and healthy indoor environments with minimal energy requirements.

An Analysis on Efficient Vertical Greening for Exterior Application in Hot and Humid Climate

The vertical greening technique offers a wide range of benefits. However, due to inadequate study and technical knowledge in this area, the efficiency of vertical greenery in providing a thermally comfortable indoor environment is not well known which acts as a main obstacle to its widespread adoption. This article reviews some of the successful vertical greening projects and field experiments performed to evaluate the thermal performance of vertical greening in tropical climates, particularly in hot and humid regions to conclude with an efficient vertical greening system for exterior wall application to provide a comfortable indoor environment in hot and humid climate.

Can heat pump heat storage system perform better for space heating in China’s primary schools? A field test and simulation analysis

The space heating system has a significant influence on the energy consumption and comfortable indoor environment for primary schools in China’s cold area. This study investigated the operational performance of heat pump systems in two primary schools. Results showed that the primary school buildings had high heating load at turn-on period every morning, which then quickly decreased when the students came to classroom. With this wide-range variation of heating load and unreasonable control strategy, the mismatch between heat source and heating demand happened very easily among the whole heating season. It then led to typical issues and poor energy efficiency of heat pump systems, including excessive space heating after school, low load ratio and frequent start-stop operation of heat pump systems, small water temperature difference and excessive water flow rate of water distribution system, etc. In allusion to those core issues, the heat pump heat storage system (HPHS) was raised for space heating in primary schools to decouple the heat supply side and the heat demand side. Then this study simulated and analyzed the operational performance of HPHS. Results showed that with reasonable control strategy, the excessive heat supply after school was effectively avoided to save almost 51% of the total heat consumption. Besides, the heat pumps could operate stably with almost full heating load for heat storage, thus reaching better energy performance with annual average COP of 5.13. Also the water distribution systems in the ground side, heat storage side and user side could reach better energy performance with high energy efficiency and reasonable water temperature difference among the heating season. Therefore, the HPHSs with reasonable control strategy could effectively solve those typical issues and are more suitable for primary schools.

Review of Window Performance in A Hot and Humid Climate

Incorrect implementation of window parameters, such as configuration, position, and size, cause an unpleasant indoor environment. The authors reviewed window performance in a hot and humid climate in this paper. Articles were screened in detail to determine eligibility, compiled, and organised according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) requirements. The articles included in this review concerned natural ventilation and window performance in a hot and humid climate. Keywords or topics were reviewed and focused on indoor environment comfort. The results demonstrated that sliding windows were unfavourable openings that were nevertheless in demand. This review was performed to guide consumers, designers, and the market of the built environment industry.

Inverse design of a thermally comfortable indoor environment with a coupled CFD and multi-segment human thermoregulation model

A thermally comfortable indoor environment is critical for ensuring the health and productivity of the occupants. To design a thermally comfortable environment, CFD-based methods assume the occupants’ surface temperature to be fixed values for simplicity and use PMV to estimate thermal comfort level. The constant surface temperature assumption would lead to inaccurate prediction of the indoor environment and the use of PMV would lead to a waste of the rich spatial information calculated by CFD. Therefore, this study developed and validated a coupled CFD and multi-node human thermoregulation model (HTM). The CFD and HTM synchronize data during the simulation and the occupant skin temperature could be updated. The final skin temperature could be used to quantify the thermal comfort level. The accuracy of the coupled model in predicting the skin temperature was validated by experimental data from literature. The coupled model was further integrated with genetic algorithm for inverse design. The inverse design of thermal environment in an office with two occupants and displacement ventilation was used for demonstration. With the CFD-HTM model, genetic algorithm was able to identify an optimal condition that leads to the least deviation of skin temperature of local body parts from the neutral values. The developed CFD-HTM coupling scheme can be used to effectively design indoor environment with improved thermal comfort.

Providing a feasible energy retrofitting technique based on polyurethane foam injection to improve windows performance in the building stock

Energy renovation of existing buildings represents an outstanding potential field for providing efficient, viable and easy-to-produce retrofitting techniques that allow addressing energy targets under a global warming scenario. Aiming to fulfil a current research gap on promoting feasible passive techniques to improve thermal performance in the building stock, this research contributes with the design, procedure and in situ application of a novel energy retrofitting solution based on the injection of polyurethane foam insulation in carpentry profiles of existing aluminium windows, which implies relevant insights towards energy efficiency and ensures more comfortable indoor environments through a quick, non-destructive and affordable solution. This innovative plan has been experimentally tested in social housing, with a monitoring campaign during summer conditions, allowing to obtain thermal results before and after the insulation injection treatment. The key outcomes highlight a favourable indoor thermal balance after the foam injection, increasing the thermal jump up to 25 % or more than 4 °C net, as the daily maximum temperature difference recorded between outdoor and indoor simultaneously. Conclusions incorporate key implications to technicians, manufacturers and construction firms, on introducing new possibilities for improving energy efficiency in existing aluminium windows with low investment, linked towards an efficient management of the built environment.

Integrated Design and Assessment for Indoor Heating, Ventilation and Air-Conditioning in Hot Summer and Cold Winter Area: A Case Study in China

Integrated design of the heating, ventilation and air-conditioning (HVAC) is indispensable to green design because the increasing demand for HVAC systems has led to the diversification of indoor terminals for residential buildings, either focusing on energy efficiency or specializing in creating comfortable indoor environments, and they have different impacts on architectural and engineering design. The paper discussed the assessment-based integration design of the HVAC system, and by introducing case experiences, the whole process of the collaboration between architects and engineers was explored. Various methods were used in the research. The analytic hierarchy process (AHP) was employed to develop the assessment structure and calculate weightings; employing fuzzy comprehensive evaluation (FCE), the social performances of HVAC systems were subjectively evaluated; simulation technology was used to calculate the energy performances; the final results were ranked by the order of preference by similarity to ideal solution (TOPSIS). The research perspective of the collaboration between architects and engineers contributed to the existing literature. Besides, different indoor terminals were analyzed from the two disciplines; an assessment tool (ATI) was conducted and could be referred to; the current green building rating tools were analyzed, and suggestions were proposed to promote the integrated design.

Atrium Design Criteria in Social and Environmental Aspects of Commercial Buildings in Klang Valley

The research was conducted to identify atrium design criteria and their impacts on social and environmental aspects at commercial buildings in the Klang Valley area, Malaysia. The design of the atrium affects the social and environmental conditions in the building. Thus, the objectives are to identify the atrium design criteria for the selected commercial buildings and to investigate their impacts on social and environmental aspects. There are two research methods namely literature study and qualitative descriptive research. The lists of atrium design criteria and their impacts on the social and environmental aspects had been produced based on literature and document reviews. Four commercial buildings in Klang Valley were selected as case studies. The findings indicate that the use of glazing roof material at the atrium promotes natural lighting and social interaction between users. Appropriate openings in the atrium space allow natural ventilation which provides energy savings. Appropriate furniture selection and layout, as well as landscaping in the atrium space, encourage the users to execute activities for longer periods of time. The large and bright atrium space allows the accommodation of various presentations, exhibitions, bazaars, and small stalls to attract the flow of users. In addition, the atrium space also provides visual access to users to understand the overall circulation of the building. To conclude, this study can be a reference in designing the atrium in buildings that are suitable for tropical climate, and understanding the atrium design criteria that contribute to the social and comfortable indoor environment for the users.

Radon levels and indoor air quality after application of thermal retrofit measures-a case study.

This study was conducted to evaluate the influence of thermal retrofit on radon levels in workrooms, and to determine whether the radon concentration in the building changes after the application of retrofit measures. In the first survey, digital Airthings Corentium Home radon detector was used for 1-month radon measurements during the heating season 2018/19. The daily averaged radon concentrations varied from 37 to 573Bq/m3 for 10 selected workrooms, while hourly averaged radon measurements showed extreme variations from 6 to 1603Bq/m3 due to radon fluctuations. In second survey, passive radon technique based on charcoal canister test kit was conducted in all basement workrooms in spring 2021. The averaged radon concentrations grouped according to flooring type in workrooms were 327Bq/m3 for parquet, 227Bq/m3 for ceramic tiles, 146Bq/m3 for vinyl flooring and 71Bq/m3 for laminate. Besides thermal insulation and airtight windows, noticeable differences in indoor radon concentration within the renovated building are primarily caused by different types of flooring. It includes various types of insulation from the ground/concrete slab: laminate, parquet (wood blocks), vinyl flooring, and ceramic tiles. Detailed analysis point out that laminate is more efficient way for radon protection than other types of flooring. An efficient ventilation system should be installed to avoid increasing occupational radon exposure and to provide healthy and comfortable indoor environment.

Traditional Passive Design Solutions as a Key Factor for Sustainable Modern Urban Designs in the Hot, Arid Climate of the United Arab Emirates

Sustainable architecture is a key approach for creating sustainable cities and reducing the impact of climate change. In hot, arid regions, the passive design traditional architecture is known for its ability to provide comfortable indoor environments and outdoor shaded areas, in contrast to the use of energy-intensive air conditioners in a great deal of modern architecture. Thus, this research used a qualitative methodology based on ENVI-met software to study, investigate, and compare the thermal performance of two urban fabrics as case studies (traditional and modern districts) in the hot, arid climate of the United Arab Emirates. The thermal performance of the old urban districts was better than the new ones, with a lower maximum potential air temperature and an improvement in the level of thermal comfort, measured by a predicted mean vote. Moreover, it was found that enhancing the shade in the outdoor open areas in the modern district, mimicking the traditional passive design solutions, resulted in lower air temperature and PMVs. This research is expected to be one step among many towards creating sustainable, innovative modern architecture.

Indoor Comfort and Energy Consumption Optimization Using an Inertia Weight Artificial Bee Colony Algorithm

A comfortable indoor environment contributes to a better quality of life and wellbeing for its occupants. The indoor temperature, lighting, and air quality are the main controlling factors of user comfort levels. The optimum control of the lighting, air conditioners, and air ventilators helps in maximizing the user’s comfort level. Nonetheless, the energy consumption of these appliances needs to be taken into consideration to minimize the operational cost and at the same time provide an environmentally friendly system. Comfort level maximization and energy consumption minimization are optimization problems. This issue is becoming more important due to the lifestyle changes caused by the COVID-19 pandemic that resulted in more time spent at home and indoors. Inertia weight artificial bee colony (IW-ABC) algorithms using linearly increasing, linearly decreasing, and exponentially increasing inertia are proposed here for the optimization of the indoor comfort index and energy usage. The multi-objective problem is tackled as a weighted single objective optimization problem. The proposed solution is tested using a dataset of 48 environmental conditions. The results of the simulation show that the IW-ABC performs better than the original ABC and other benchmark algorithms and the IW-ABC with linear increasing inertia weight has the most improved convergence behavior.

Adaptive damper control for HVAC systems based on human occupancy and indoor parameters: A development study

Occupancy-based strategies for the control of ventilation systems in buildings are effective for achieving energy savings and user comfort. Savings in energy consumption of more than 50% can be achieved by controlling heat, ventilation, and air conditioning (HVAC) systems with accurate sensory and occupancy information. In this study, the flow through the damper of the variable area valve (VAV) system and the speed of the blower’s variable frequency drive (VFD) are controlled in the HVAC system, on the basis of human occupancy and indoor parameters, namely, temperature and humidity, segment-wise in the building. In the proposed model, the flapper angle of the VAV is estimated using the indoor temperature, external temperature, and number of occupants. The occupancy data are fed to the controller proposed to regulate the flow through the ducts of the system, which is based on the flapper angle of the VAV, in order to maintain human comfort. The proposed scheme makes it possible to detect abnormalities in energy utilization and to trace maximum utilization in the building based on occupancy, with the control parameters of the HVAC adjusted for a comfortable indoor environment. Performance evaluation of the VAV system with its proposed control strategy, temperature, and flow distribution is simulated using Fluent software. A laboratory grade prototype incorporating the proposed control strategy is then developed, tested under three different conditions, and the results are reported. The experimental results show that an energy saving of 18% can be achieved.

Multifactorial approach to indoor environmental quality perception of social housing residents in Northern Spain

ABSTRACT Social housing users are generally more vulnerable due to age and socioeconomic conditions and have to deal with specific problems related to vulnerability to poor indoor environment exposure. The current housing model does not respond to the diversity of family structures and their needs, and it is, therefore, essential to integrate residents’ perspectives into the process of improving their quality of life, health and comfort. This study aims to analyse the factors that influence the perceived Indoor Environmental Quality and comfort of public rental housing. It also aims to study occupants’ perceived comfort in relation to the characteristics of the dwellings. To achieve the objective of the study, a multifactorial approach has been applied to a sample of 283 dwellings in 16 buildings of the public rental stock in the Autonomous Community of the Basque Country, Spain, with data obtained in a survey conducted in the winter. The analysis of the incident variables in the perceived indoor environment supports the idea of the influence of occupants’ perspectives and the subjectivity of their responses in the comfort analyses and provides new insight into the relationship between the physical characteristics of social housing and households’ perceived comfort.

A State of Art Review on Methodologies of Occupancy Estimating in Buildings from 2011 to 2021

Occupancy information is important to building facility managers in terms of building energy efficiency, indoor environmental quality, comfort conditions, and safety management of buildings. When combing the distribution characteristics of the literature, it is found that the field of estimating occupancy counts is a very active area. Researchers from various countries have undertaken extensive explorations to obtain more research results. In this survey, the commonly used occupancy measurement systems and algorithms are described. Through the analysis and research of different occupancy measurement systems and algorithms, their advantages, disadvantages, and limitations are summarized, so that researchers can use them selectively. As for how to choose the method of estimating occupancy counts, suggestions are given in terms of the range of people, accuracy, cost, and privacy. There are still many pressing issues relating to high-density crowd occupancy counting, complex environmental impact, and system robustness. According to the current research progress and technology development trend, the possible future research directions are pointed out. The innovation of this review is the quantitative analysis of the selection of occupancy measurement systems for different ranges of people, and the occupancy counting accuracy situation of different measurement systems and algorithms. It provides more informed opinions on the selection of practical applications. It can be used by other researchers as a starting point for their research and/or project work.

Mean radiant temperature calculated based on radiant heat dissipation of human body addressing effect of emissivity of inner surfaces of envelope

Low-emissive coatings applied to the inner surfaces of the envelope effectively reduce the energy consumption of buildings, but significantly affect the radiant heat dissipation (RHD) of the human body. The mean radiant temperature (MRT) from the existing method cannot accurately estimate the RHD of the human body, which deteriorates thermal comfort thereby impeding the application of low-emissive coatings. This study proposes a calculation method of the MRT which accurately estimates the RHD of the human body. Case studies demonstrate that with the emissivity of the inner surfaces of the envelope decreasing from 0.9 to 0.1, the existing method inaccurately estimates the RHD of the human body with an error of up to 132%, while the proposed method reduces the error to less than 2.5%. The MRT from the existing method results in an error in thermal comfort evaluation (indicated by Predicted Mean Vote) up to 0.31 which fails the desired accuracy. The MRT from the proposed method effectively reduces the error in thermal comfort evaluation to be less than 0.01 satisfying the desired accuracy. Therefore, the proposed method contributes to the development of thermally comfortable and energy-efficient indoor environments with low-emissive coatings.