Thermal Sleeping Environments

Control and Optimization

1st Edition - March 22, 2025
Imprint: Woodhead Publishing
Authors: Shiming Deng, Zhongping Lin, Dongmei Pan, Ning Mao, Jing Du, Guanyu Fang
Language: English
Paperback ISBN:
9 7 8 - 0 - 4 4 3 - 2 8 8 7 6 - 0
eBook ISBN:
9 7 8 - 0 - 4 4 3 - 2 8 8 7 7 - 7

The connection between the sleep environment and quality of sleep is significant. To get a good night's rest, a person needs to be in an environment conducive to sleep, which means… Read more

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The connection between the sleep environment and quality of sleep is significant. To get a good night's rest, a person needs to be in an environment conducive to sleep, which means having or creating the right conditions for it. Thermal Sleeping Environments: Control and Optimization provides a comprehensive coverage on cutting-edge heating, ventilation, and air-conditioning (HVAC) equipment; novel bed-based task/ambient conditioning (TAC) systems; and advanced materials for building envelopes, bedroom furniture, and textiles for beddings. The performance of the technologies presented is analyzed through thermal comfort charts and modeling endeavors, which are in turn validated by the notions of human physiological responses during sleep. The foundational principles of fluid mechanics alongside sustainably built environment and energy efficiency considerations also complement this discussion.
Written by academic experts who aim to compile a unique reference resource to foster further subject matter research, this book should appeal to a broad range of readers whose work or study interests focuses on sustainable buildings and the wellbeing of their occupants.

Title of Book
Cover image
Title page
Table of Contents
Copyright
About the authors
1. Introduction
1.1 Background
1.2 Objectives and scopes
1.3 Outlines of the book
2. Background
2.1 Introduction
2.2 Fundamentals of sleep, human physiology, and thermoregulation during sleeps—an overview
2.2.1 Fundamentals of sleep
2.2.2 Fundamentals of human physiology during sleep
2.2.3 Thermoregulation during sleep
2.3 Previous studies on sleep quality and sleeping thermal environment
2.3.1 Factors that affects sleeping quality
2.3.2 Investigations of sleeping thermal environment preference
2.4 The need for controlling sleeping thermal environment and bedroom air conditioning—a questionnaire survey carried out in Hong Kong
2.4.1 Method
2.4.2 Results
2.4.2.1 Indoor thermal environments
2.4.2.2 Use of bedding and sleepwear
2.4.2.3 Bedroom ventilation and indoor air quality
2.4.2.4 Other issues
2.4.3 Discussions
2.5 Concluding remarks
2.6 AI disclosure
3. Indoor space thermal loads for a sleeping environment
3.1 Introduction
3.2 Characteristics of nighttime space cooling load
3.2.1 Description of the model building and the assumptions used in the numerical study
3.2.1.1 Occupancy pattern
3.2.1.2 Building envelope
3.2.1.3 Operating patterns of ACUs
3.2.1.4 Internal heat gains and ventilation
3.2.1.5 Indoor design settings
3.2.1.6 Meteorological data
3.2.2 Results
3.2.2.1 Cooling load characteristics under the three operating modes on the summer design day
3.2.2.2 Cooling load characteristics at DOM
3.2.2.3 Cooling load characteristics at ADM
3.2.2.4 Breakdown of the total cooling load in west-facing Bedroom 3 at NOM
3.2.2.5 Indoor air temperature and mean radiant temperature variation at NOM
3.2.2.6 Effects of indoor air temperature set point on cooling load characteristics for a bedroom at NOM
3.2.3 Discussions
3.2.3.1 The differences in the cooling load characteristics between at NOM and at ADM
3.2.3.2 The differences between the cooling load characteristics at NOM and that at DOM
3.2.3.3 Sizing of RACUs for nighttime air conditioning in bedrooms
3.3 Impacts and mitigation measures of daytime heat gain and storage on nighttime cooling load
3.3.1 Model development and simulation conditions
3.3.1.1 Model development
3.3.1.2 Schedules of A/C operation, internal heat gains, and ventilation
3.3.1.3 Indoor design air temperature and meteorological data
3.3.2 Analysis on nighttime cooling load characteristics in the simulated bedroom
3.3.2.1 Nighttime cooling load characteristics in the simulated bedroom
3.3.2.2 Effects of the thermal mass of the west-facing external wall in the simulated bedroom on the nighttime cooling load on the summer design day
3.3.3 Modifying the external wall to reduce the nighttime cooling load in the simulated bedroom
3.3.3.1 Effects of varying the width of the air gap on the total nighttime cooling load in the studied bedroom
3.3.3.2 Effects of varying the width of inside and outside concrete layers of the west-facing external wall on the total nighttime cooling load in the studied bedroom
3.3.3.3 Effects of ventilating the air gap on the total nighttime cooling load in the studied bedroom on the summer design day
3.3.3.4 Effects of adhering aluminum foils on the surfaces of an air gap on the total nighttime cooling load
3.3.3.5 Discussions
3.4 Concluding remarks
4. Outdoor air ventilation for an indoor sleeping environment
4.1 Introduction
4.2 Field studies
4.2.1 Field survey on overnight CO2 levels in bedrooms equipped with RACs
4.2.2 Field studies on outdoor ventilation rates in bedrooms equipped with RACs
4.3 Laboratory experiments on outdoor ventilation rates with RACs
4.3.1 Experimental setup
4.3.2 Experimental conditions
4.3.3 Results
4.4 Discussions
4.4.1 Ventilation in residential buildings employing RACs
4.4.2 Ventilation in bedrooms employing RACs at nighttime
4.5 Concluding remarks
5. A thermal comfort model for a sleeping person
5.1 Introduction
5.2 Development of a thermal comfort model for a sleeping person
5.2.1 Energy balance of a human body
5.2.2 Thermal exchanges between a human body and its environment
5.2.2.1 Sensible heat loss from skin
5.2.2.2 Evaporative heat loss from skin
5.2.2.3 Respiratory losses
5.2.3 Assumptions and modifications adopted for sleeping environments
5.2.4 Conditions for thermal comfort in sleeping environments
5.2.5 Comfort equation for a sleeping person
5.2.6 PMV and PPD for sleeping environments
5.3 Concluding remarks
6. The thermal resistance of bedding systems used in thermal comfort model
6.1 Introduction
6.2 Experimental method and bedding systems measured
6.2.1 Experimental method
6.2.2 Selection of bedding systems including bedding, sleepwear, bed, and mattress
6.2.3 The physical properties of bedding items and sleepwear
6.2.4 Experimental conditions
6.3 Results
6.3.1 Effect of the percentage coverage of body surface area by bedding and bed
6.3.2 Effect of bedding
6.3.3 Effect of sleepwear
6.3.4 Effect of bed and mattress
6.4 Discussions
6.4.1 The factors influencing the total resistance/insulation of a bedding system
6.4.2 The usefulness of a summer quilt
6.5 Concluding remarks
7. Solving a comfort equation and establishing comfort charts
7.1 Introduction
7.2 Establishment of a comfort equation and comfort charts
7.3 Discussions
7.3.1 The effect of the total insulation of a bedding system on thermal comfort
7.3.2 Air-conditioning culture
7.4 Concluding remarks
8. A mathematical model for the total insulation value of a bedding system
8.1 Introduction
8.2 Model development and validation
8.2.1 Model development
8.2.1.1 Assumptions
8.2.1.2 Total insulation value of a bedding system
8.2.1.3 Determination of the parameters used in the mathematical model
8.2.2 Model validation
8.2.2.1 Result comparison for M1 bed
8.2.2.2 Result comparison for M2 bed type
8.2.2.3 Error analysis
8.3 Discussions
8.3.1 Effects of the percentage coverage of body surface covered by beddings and bed with mattress on the total insulation value of a bedding system
8.3.2 Effects of bedding on the total insulation value of a bedding system
8.3.3 Effects of bed types on the total insulation value of a bedding system
8.4 Concluding remarks
9. A four-node thermoregulation model to forecast the thermal physiological reactions of a sleeping person
9.1 Introduction
9.2 Development of the thermoregulation model
9.2.1 Gagge's two-node model
9.2.1.1 Controlled system
9.2.1.2 Controlling system
9.2.2 Modifications to the Gagge's two-node model
9.2.2.1 The skin layer
9.2.2.2 Set points for skin and core temperatures
9.2.2.3 Three different thermoregulatory responses
9.2.3 The four-node thermoregulation model for a sleeping person
9.2.3.1 The controlled system
9.2.3.2 The controlling system
9.3 Validation of the thermoregulation model
9.3.1 Validation using Haskell’s experiment results
9.3.2 Validation using Okamoto-Mizuno’s experiment results
9.4 Concluding remarks
10. Numerical studies on the microclimate surrounding a sleeping person
10.1 Introduction
10.2 Computational approaches
10.2.1 Development of a sleeping computational thermal manikin
10.2.2 Air-conditioned space with a displacement ventilation system
10.2.3 Grid generation
10.2.4 Submodels in the CFD software packages used
10.2.5 Boundary conditions
10.2.6 Simulated study cases
10.3 Results analysis of the first numerical study
10.3.1 Simulated airflow field around the naked SCTM
10.3.2 Simulated air temperature distribution around the naked SCTM
10.3.3 Simulated mean internal surface temperatures
10.3.4 Simulated heat transfer characteristics
10.4 Results analysis of the second numerical study
10.4.1 The definition of the thermal neutrality for a sleeping person
10.4.2 The thermal neutrality for a naked sleeping person
10.4.3 Effects of total insulation value of a bedding system on the thermal neutrality of a sleeping person
10.5 Concluding remarks
11. Novel bed-based task/ambient conditioning systems and their optimizations for a thermally neutral environment with a minimum energy use
11.1 Introduction
11.2 Design and performance of a ductless bed-based TAC system
11.2.1 Method
11.2.1.1 Design of the ductless TAC system
11.2.1.2 Experimental setup
11.2.1.3 Measurement methods
11.2.1.4 Experimental conditions
11.2.2 Results
11.2.2.1 Thermal performances
11.2.2.2 Ventilation performance
11.2.2.3 Energy-saving performance
11.3 Airflow and moisture transport inside the bedroom with a TAC system
11.3.1 Method
11.3.1.1 Experimental method
11.3.1.2 Numerical method
11.3.2 Results
11.3.2.1 Horizontally stratified temperature
11.3.2.2 Skin temperature of the thermal manikin
11.3.2.3 Air velocity distribution
11.3.2.4 Relative and absolute air humidity distributions
11.4 Effects of supply outlet and return inlet on TAC performances
11.4.1 Method
11.4.1.1 Different heights of supply air outlet
11.4.1.2 Different return air inlets
11.4.2 Performance analysis on effects of supply outlets
11.4.2.1 Ventilation performance
11.4.2.2 Thermal comfort
11.4.2.3 Energy use
11.4.3 Performance analysis on effects of return inlet
11.4.3.1 Draft risk
11.4.3.2 Air diffusion performance
11.4.3.3 Energy use
11.5 Optimization of TAC operating performance
11.5.1 Method
11.5.1.1 The total insulation value of beddings and bed
11.5.1.2 Study cases
11.5.1.3 Performance evaluation method
11.5.2 Results
11.5.2.1 Prediction models for PMV and EUC
11.5.2.2 Thermally neutral operating and comfort line
11.5.2.3 Operating parameter optimization
11.6 Concluding remarks
12. A radiation-based TAC system including moisture distribution and a way of mitigating condensation in a sleeping environment
12.1 Introduction
12.2 Experimentation, results, and analysis
12.2.1 An experimental setup
12.2.2 The experimental bedroom
12.2.3 Measurement methods
12.2.4 Experimental conditions and cases
12.2.5 Experimental results and analysis
12.2.5.1 Indoor air temperature and MRT
12.2.5.2 Air velocity
12.2.5.3 Thermal comfort evaluation
12.2.5.4 Ventilation performance evaluation
12.2.5.5 Draft risk performance
12.2.5.6 Potential condensation risk
12.3 Establishment of a numerical model, numerical results, and analysis
12.3.1 Geometry model
12.3.2 CFD method
12.3.3 Boundary conditions and numerical cases
12.3.4 Validation of the CFD method (Case L3.0)
12.3.4.1 Mesh sensitivity
12.3.4.2 Selection of radiation model
12.3.4.3 Surface temperature validation
12.3.5 Numerical results and analysis
12.3.5.1 Thermal comfort
12.3.5.2 Energy saving
12.3.5.3 Results visualization and comparison at five selected cases
12.3.5.4 Draft risk
12.4 Condensation risk for the radiant panel of the R-TAC system
12.4.1 Moisture distribution in the bedroom at two heights of the supply vent
12.4.2 Noncondensation regions with different panel temperatures at two heights of the supply vent
12.5 Concluding remarks
13. A bed-based air source heat pump space heating system in a sleeping environment
13.1 Introduction
13.2 Experimentation
13.2.1 Description of an experimental B-ASHP system
13.2.2 Details of the bed-based heating terminal
13.2.3 Measurement methods
13.2.4 Description of test cases
13.3 Experimental results and analysis of the proposed B-ASHP system
13.3.1 Measured dynamic operating performances of the experimental B-ASHP system after starting up
13.3.2 Measured steady-state performances of the experimental B-ASHP system
13.3.3 Comparative studies between using the bed-based terminal and convection-based heating terminal
13.3.4 Uniformity of bed surface temperature
13.4 Concluding remarks
Abbreviations
14. Practical guides to control indoor thermal environments for quality sleep
14.1 Introduction
14.2 Preferred indoor air temperature and humidity for air-conditioned sleeping environments
14.3 Selecting appropriate bedding and sleepwear in air-conditioned sleeping environments
14.4 Using fans for controlling non-air-conditioned thermal sleeping environments in summer
14.5 Using night-ventilation in non-air-conditioned thermal sleeping environments
14.6 Concluding remarks
15. Conclusions and future perspectives
15.1 Conclusions of the present work
15.2 Future perspectives
Index

Shiming Deng

Shiming Deng is a Professor of Mechanical Engineering at the Department of Mechanical and Industrial Engineering, Qatar University. Prior to this, he worked at The Hong Kong Polytechnic University from 1992 to 2021. His research interests include controlling thermal sleeping environments and air source heat pumps, among others, with a total of more than 300 publications in international journals.

Affiliations and expertise

Professor, Department of Mechanical and Industrial Engineering, Qatar University, Doha, Qatar

Zhongping Lin

Zhongping Lin received his PhD from the Department of Building Services Engineering at The Hong Kong Polytechnic University in 2005 and is currently a Professor at the School of Mechanical Engineering, Tongji University. His research interests include controlling indoor air quality, thermal environments, pollutant control, and clean air technology. He is also a member of the National Technical Committee for Standardization of Clean Rooms and Related Controlled Environments.

Affiliations and expertise

Professor, Department of Energy Engineering, School of Mechanical Engineering, Tongji University, Shanghai, China

Dongmei Pan

Dongmei Pan is currently a Lecturer at the School of Mechanical and Automobile Engineering, South China University of Technology. Her research interests include controlling thermal sleeping environments and building energy savings, among others, with a total of more than 40 publications in international journals.

Affiliations and expertise

Lecturer, School of Mechanical and Automobile Engineering, South China University of Technology, Guangzhou, China

Ning Mao

Ning Mao is currently an Associate Professor at the College of Pipeline and Civil Engineering, China University of Petroleum (East China). His current research work is related to building envelopes for energy saving, phase-change materials, heat pumps, indoor thermal environment (including sleeping thermal comfort and ventilation), and multi-objective optimization, among others.

Affiliations and expertise

Associate Professor, Department of Gas Engineering, College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China

Jing Du

Jing Du is currently a Lecturer at School of Construction Engineering, Shenzhen Polytechnic University. Her research interests include sleeping thermal comfort, indoor thermal environment simulation, and many others.

Affiliations and expertise

Lecturer, School of Construction Engineering, Shenzhen Polytechnic University, Shenzhen, China

Guanyu Fang

Guanyu Fang, after receiving his PhD from the Department of Building Services Engineering at The Hong Kong Polytechnic University in 2021, joined the R&D team at PaXini Technology Ltd., a company of universal humanoid robots for multiple scenarios and automation technology. His current research interests include sleeping thermal comfort, air source heat pumps, and energy-saving technologies for buildings, among others.

Affiliations and expertise

Engineer, PaXini Technology Ltd., Shenzhen, China

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Thermal Sleeping Environments

Control and Optimization

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Institutional subscription on ScienceDirect

Shiming Deng

Zhongping Lin

Dongmei Pan

Ning Mao

Jing Du

Guanyu Fang

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