Research

22 pages, 5286 KiB

Open AccessArticle

An Investigation of the Energy-Saving Optimization Design of the Enclosure Structure in High-Altitude Office Buildings

by Wenjing Sun, Lixing Chen, Baimu Suolang and Kai Liu

Buildings 2024, 14(3), 645; https://doi.org/10.3390/buildings14030645 - 29 Feb 2024

Viewed by 557

Concerning the double carbon national strategy, the energy-saving renovation of old buildings has become one of the most important tasks of energy conservation and emission reduction in construction in China. There are many problems, such as high energy consumption, thermal environment, and poor [...] Read more.

Concerning the double carbon national strategy, the energy-saving renovation of old buildings has become one of the most important tasks of energy conservation and emission reduction in construction in China. There are many problems, such as high energy consumption, thermal environment, and poor thermal comfort. Taking Lhasa as an example, this study adopts field research, questionnaire interviews, on-site measurements, numerical simulations, and other methods to propose suitable energy-saving potential excavation points and thermal optimization strategies for office building envelopes in Lhasa through software simulation. Additionally, typical office buildings are selected to carry out the energy-saving renovation of envelopes with the goal of improving indoor thermal comfort to validate the feasibility of the energy-saving renovation strategies. The results show the following: (1) The measured and predicted thermal neutral temperatures of the office population in Lhasa are 16.5 °C and 18.9 °C, respectively. The 90% acceptable temperature range is from 16.10 °C to 21.77 °C, and the occupants of the office buildings in Lhasa have a higher tolerance for cold than predicted. (2) The passive measures adapted to Lhasa are prioritized in the order of passive solar energy, high-heat-capacity materials, and nighttime ventilation. (3) Through the optimization of the enclosure structure of existing office buildings, the improvement of the heat storage capacity of the outer enclosure structure, and the increase in the window opening area to increase natural ventilation, the indoor thermal comfort of the renovated buildings is effectively improved. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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21 pages, 2932 KiB

Open AccessArticle

Field Study to Compare and Evaluate Summer Thermal Comfort of School Buildings with Different Moderate Thermal Mass in Their Building Elements

by Bin Su, Peter McPherson, Renata Jadresin Milic, Xinxin Wang, Sameh Shamout and Yifeng Liang

Buildings 2023, 13(12), 2913; https://doi.org/10.3390/buildings13122913 - 22 Nov 2023

Viewed by 524

Abstract

Previous studies show that moderate thermal mass in school building elements can positively impact the winter indoor thermal environment in a temperate climate with mild, humid winters. Based on a field study, this research contributes new physical data of the summer indoor thermal [...] Read more.

Previous studies show that moderate thermal mass in school building elements can positively impact the winter indoor thermal environment in a temperate climate with mild, humid winters. Based on a field study, this research contributes new physical data of the summer indoor thermal environment of Auckland school buildings with different designs of moderate thermal mass in their building elements to add to the previous winter field-study data and demonstrates that a school building with moderate thermal mass is adequate in a temperate climate with mild, humid winters and warm, dry summers. This field study compared and evaluated the summer indoor thermal environment of classrooms with different moderate thermal mass in their building elements during the summer school term and the summer school holidays. This study found that a classroom with thermal mass in its building elements has 19% to 21% more time in summer than a classroom without any thermal mass in its building elements when indoor air temperatures are within the thermal comfort zone, which was solely impacted by the building’s thermal performance. This study established a suitable research method to analyse the field-study data and identify the differences in the indoor thermal environments of the school buildings with different designs of moderate thermal mass in their building elements. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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22 pages, 7072 KiB

Open AccessArticle

Exploration of Campus Environmental Health Issues and Individual Disparities in Environmental Perceptions Based on Daily Activity Path

by Jie Deng, Bin Chen, Changfeng Fu and Jia Du

Buildings 2023, 13(10), 2544; https://doi.org/10.3390/buildings13102544 - 08 Oct 2023

Cited by 1 | Viewed by 720

Abstract

Individual surveillance methods help identify subtle health risks that may be overlooked in room surveillance. This study aims to investigate campus environmental health issues by tracking university students’ daily exposure processes in their living environment. A field survey was conducted among 58 students [...] Read more.

Individual surveillance methods help identify subtle health risks that may be overlooked in room surveillance. This study aims to investigate campus environmental health issues by tracking university students’ daily exposure processes in their living environment. A field survey was conducted among 58 students at a university in northern China. They were equipped with a “companion data collection device” to record exposure experiences and activity pathways related to light, heat, and air environments. A questionnaire was also administered. Morning exposure to adequate light (Circadian Stimulus ≥ 0.3) increased alertness, but only 57% of undergraduates met this standard, and 67% of those waking up after 8 AM experienced this. People with different preferences chose diverse dining spots, and those favoring “roasted,” “stir-fried,” and “deep-fried” foods encountered higher PM2.5 pollution concentrations during meals. During periods of central heating, there is a trade-off between ventilation and heating efficiency. “Slightly open window” for bedroom ventilation at night resulted in a slight temperature decrease of about 1.2 °C but effectively controlled the increase in CO₂ concentrations (about 180 ppm). Companion-type data collection shifts focus from buildings to individuals, providing the means and basis for identifying potential health risks in daily campus life. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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27 pages, 6069 KiB

Open AccessArticle

Multi-Objective Optimization of Ultra-Low Energy Housing in Hot Summer Cold Winter Climate Zone of China Based on a Probabilistic Behavioral Model

by Junmi Xiang, Hongcheng Liu, Xiaojun Li, Phil Jones and Emmanouil Perisoglou

Buildings 2023, 13(5), 1172; https://doi.org/10.3390/buildings13051172 - 28 Apr 2023

Cited by 1 | Viewed by 1525

Abstract

Occupant behavior has an important impact on building energy consumption, and the accuracy of an occupant behavior model directly affects the reliability of energy consumption simulation results. Ultra-low energy buildings are crucial to achieving building energy conservation and carbon dioxide reduction in China. [...] Read more.

Occupant behavior has an important impact on building energy consumption, and the accuracy of an occupant behavior model directly affects the reliability of energy consumption simulation results. Ultra-low energy buildings are crucial to achieving building energy conservation and carbon dioxide reduction in China. In order to effectively promote the development of ultra-low energy buildings in Hot Summer and Cold Winter Climate Zones. where most residents adopt a “part-time, part-space” pattern of intermittent energy use behavior, and to solve the problem of poor indoor thermal environments and the high incremental cost of ultra-low energy, the study described in this paper takes Changsha as an example to carry out a multi-objective optimization study on ultra-low energy housing using a probabilistic behavioral model. On the basis of a probability model representing the residents’ actual behavior in Changsha, the optimization objective indicators, key variables and the technology benchmarks for ultra-low energy building were determined, then multi-objective optimization was carried out for a range of energy efficient technologies to obtain the Pareto optimal solutions. The results showed that the set of optimal solutions could reduce energy demand by 50.2 to 60.2% and reduce indoor thermal discomfort time by 3.52–11.09% compared with those of a reference base case, which just meets the requirements of the current design standard for energy efficient domestic buildings. An optimum solution for energy savings and indoor thermal comfort, along with economic costs, was identified, which can assist in decision-making by providing different preferences and provide useful reference for the design of ultra-low energy buildings in Hot Summer and Cold Winter Climate regions. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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14 pages, 2589 KiB

Open AccessArticle

Variable Differential Pressure Control Strategy for Variable Water Flow Air Conditioning Systems

by Haoyi Zhufang, Yu Huang, Yulong Dai and Changzhi Yang

Buildings 2023, 13(4), 903; https://doi.org/10.3390/buildings13040903 - 29 Mar 2023

Viewed by 1594

Abstract

In large-scale air conditioning water systems, variable water flow (VWF) control strategies are frequently utilized to conserve energy. This paper presents a variable differential pressure (DP) set-point control strategy for VWF air conditioning systems based on the pipeline characteristic curve. This strategy bifurcates [...] Read more.

In large-scale air conditioning water systems, variable water flow (VWF) control strategies are frequently utilized to conserve energy. This paper presents a variable differential pressure (DP) set-point control strategy for VWF air conditioning systems based on the pipeline characteristic curve. This strategy bifurcates the most unfavorable loop into two segments: the equivalent main pipe (EMP) and the most unfavorable terminal branch pipe (MUTBP). Initially, the impedance of the EMP is obtained by curve fitting the measured values of the water supply and return main pipes (WSRMP), as well as the MUTBP. Subsequently, by calculating the disparity between the DP of the actual pipeline and the DP of the EMP, and comparing it with the DP of the MUTBP, the optimal working condition point for pipeline operation can be identified. Finally, a theoretical calculation is conducted on a typical air conditioning water system. This adjustment strategy achieves an energy-saving rate of 15.27%, 12.10%, and 11.50%, respectively, under the three adjustment conditions of closing the nearest terminal, the middle terminal, and the most unfavorable terminal, as compared with the constant DP set-point control strategy of WSRMP. This strategy boasts fewer control devices, a simple control system, and better operability and engineering applicability than other strategies. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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14 pages, 13333 KiB

Open AccessArticle

Highway to the Comfort Zone: History of the Psychrometric Chart

by Eric Teitelbaum, Clayton Miller and Forrest Meggers

Buildings 2023, 13(3), 797; https://doi.org/10.3390/buildings13030797 - 17 Mar 2023

Cited by 2 | Viewed by 4241

Abstract

The psychrometric chart is the most common data visualization technique for the designers of thermal comfort systems worldwide. From its humble roots as means of expressing the characteristics of air in building systems design, the use of the chart has grown to include [...] Read more.

The psychrometric chart is the most common data visualization technique for the designers of thermal comfort systems worldwide. From its humble roots as means of expressing the characteristics of air in building systems design, the use of the chart has grown to include the representation of the zones of human thermal comfort according to both conventional and adaptive models. In this paper, we present an extensive history of this development and the fallacies with representing comfort simply as a box that sometimes moves on the chart. The origins of the link between refrigeration control and comfort control are examined through archival reviews, examining the works of Carrier, Yagoglou, and their contemporaries in the context of modern comfort mischaracterizations. A clearer understanding of the mapping of comfort, control, and climate metrics with psychrometrics is reported, and a critique of the conflation is reported to increase awareness of the limitations of such treatment of these three critical domains. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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22 pages, 7725 KiB

Open AccessArticle

Occupant Heating Patterns of Low-Temperature Air-to-Air Heat Pumps in Rural Areas during Different Heating Periods

by Xiaoyi Chen, Ziqiao Li, Longkang Dai, Wenmao Zeng and Meng Liu

Buildings 2023, 13(3), 679; https://doi.org/10.3390/buildings13030679 - 03 Mar 2023

Viewed by 1045

Abstract

Understanding the actual heating patterns of air-to-air heat pumps (AAHP) in rural areas is crucial for energy planning and clean-heating policy optimization. To explore the influence of outdoor climate change on occupants’ heating patterns when using AAHPs in rural areas, the heating season [...] Read more.

Understanding the actual heating patterns of air-to-air heat pumps (AAHP) in rural areas is crucial for energy planning and clean-heating policy optimization. To explore the influence of outdoor climate change on occupants’ heating patterns when using AAHPs in rural areas, the heating season was classified into three periods: the early heating period (EH), the mid heating period (MH), and the late heating period (LH). The investigation was conducted in rural areas of northern China, and indoor environmental parameters were measured from December 2021 to March 2022. Occupants completed household questionnaires about their heating habits before heating and phone interviews at the end of heating. This paper proposes clustering analysis to identify the AAHP heating pattern in rural areas. The results revealed four typical heating patterns of AAHP utilization. Occupant heating behaviors were dominated by the outdoor temperature fluctuation. In particular, during the mid heating period, the heating operation time periods and the heating duration were longer than that of other heating periods. Moreover, the heating patterns in living rooms were different from that in bedrooms. Room occupancy had an impact on household heating demands. These results could provide guidance for energy planning and the development of clean heating policy in the rural area. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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24 pages, 1656 KiB

Open AccessArticle

Comfort and Economic Viability of Personal Ceiling Fans Assisted by Night Ventilation in a Renovated Office Building

by Mattis Knudsen, Romina Rissetto, Nicolas Carbonare, Andreas Wagner and Marcel Schweiker

Buildings 2023, 13(3), 589; https://doi.org/10.3390/buildings13030589 - 23 Feb 2023

Cited by 3 | Viewed by 2210

Abstract

An expected increase in the use of air conditioning by 2050 will significantly increase electricity demand and come at a cost to the environment. Implementing passive cooling strategies and focusing on personal environmental control systems (PECSs) could help to address this issue. While [...] Read more.

An expected increase in the use of air conditioning by 2050 will significantly increase electricity demand and come at a cost to the environment. Implementing passive cooling strategies and focusing on personal environmental control systems (PECSs) could help to address this issue. While numerous studies have investigated the positive impact of PECSs on thermal comfort and energy savings, their overall economic benefit has been poorly addressed. We present an economic evaluation of personal fans for an office building in Germany. Building performance simulation was used to compare passive and active cooling concepts, and sensitivity analysis was performed for different climate scenarios. A cost-benefit analysis was carried out, including an assessment of investment and operating costs and the monetary value of relative performance. The transferability of comfort and productivity into costs is the novelty of this paper. The results showed that by supplementing night ventilation with personal fans, discomfort hours could be reduced by up to 50%. However, the initial investment of the fan is not compensated by savings in productivity losses compared to night ventilation alone. A reduction in the cost of the technology could help to economically offset the investment. The results contribute to the literature on the economic evaluation of a PECS by proposing a framework to motivate its implementation in buildings. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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19 pages, 5893 KiB

Open AccessArticle

Study on the Performance of Personal Heating in Extremely Cold Environments Using a Thermal Manikin

by Sishi Li, Yue Deng and Bin Cao

Buildings 2023, 13(2), 362; https://doi.org/10.3390/buildings13020362 - 28 Jan 2023

Cited by 2 | Viewed by 1417

Abstract

Cold protection for outdoor workers is crucial for their health and thermal safety in winter. Personal heating is considered an effective measure to solve the problem, which can significantly improve thermal comfort. However, according to the present studies, a uniform assessment of different [...] Read more.

Cold protection for outdoor workers is crucial for their health and thermal safety in winter. Personal heating is considered an effective measure to solve the problem, which can significantly improve thermal comfort. However, according to the present studies, a uniform assessment of different personal heating measures is hard to obtain. This study explored four typical types of personal heating measures (electrically heated garment, electrically heated garment with an aerogel layer, electrically heated seat, and chemically heated insole) in different cold environments. Clothing insulation, effective heating power (P_eff), and heating efficiency (

η

) were measured by a thermal manikin with a constant temperature in nine environmental conditions. Three levels of two critical environmental factors (air temperature (T_a): −5 °C, −10 °C, and −15 °C; air velocity (V_a): <0.1 m/s, 0.5 m/s, and 1.0 m/s) were crossed orthogonally to form the nine environmental conditions. The results indicated that T_a had no significant effect on clothing insulation, while elevated V_a significantly decreased clothing insulation. When V_a increased from 0 m/s to 1 m/s, the air layer inside the garment was squeezed, causing a 0.6–0.9 clo decrease in total clothing insulation. Decreased T_a and elevated V_a reduced the P_eff and

η

of electrical heating measures while they improved the P_eff and

η

of chemical heating insoles. The P_eff and

η

of the garment dropped to 8.2 W and 21%, respectively, at −15 °C and 1.0 m/s. In addition, the aerogel layer could effectively improve the P_eff and

η

of the garment. The improvement was weakened by decreased T_a and elevated V_a. The corrective power values of personal heating measures in different environments were calculated to guide the design and application of personal heating. Full article

(This article belongs to the Special Issue Indoor Environment and Thermal Comfort Performance of Buildings)

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