See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/264838002

Individualisation of personal space in hospital environment

Article  in  International Journal of Exergy · January 2014

DOI: 10.1504/IJEX.2014.060279

CITATIONS

7READS

238

3 authors:

Some of the authors of this publication are also working on these related projects:

Study on Thermal Environment and Adaptive Thermal Comfort of Occupants in Temporary Shelters in Nepal after Massive Earthquake 2015 View project

Slovenian Research Agency (Programme P2-0158) View project

Mateja Dovjak

University of Ljubljana

41 PUBLICATIONS   208 CITATIONS   

SEE PROFILE

Masanori Shukuya

Tokyo City University

144 PUBLICATIONS   1,128 CITATIONS   

SEE PROFILE

Aleš Krainer

Universy of Ljubljana

47 PUBLICATIONS   105 CITATIONS   

SEE PROFILE

All content following this page was uploaded by Masanori Shukuya on 04 September 2014.

The user has requested enhancement of the downloaded file.

Int. J. Exergy, Vol. 14, No. 2, 2014 125

Copyright © 2014 Inderscience Enterprises Ltd.

Individualisation of personal space in hospital environment

Mateja Dovjak* Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova cesta 2, 1000 Ljubljana, Slovenia Fax: +386 1 4250688 E-mail: mdovjak@fgg.uni-lj.si *Corresponding author

Masanori Shukuya Laboratory of Building Environment, Tokyo City University, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Yokohama 224-8551, Japan Fax: +81 45 910 2553 E-mail: shukuya@tcu.ac.jp

Aleš Krainer Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova cesta 2, 1000 Ljubljana, Slovenia Fax: +386 1 4250688 E-mail: akrainer@fgg.uni-lj.si

Abstract: The purpose of the paper is to test a Low Exergy heating and cooling system (LowEx system) that enables the creation of healing and comfort conditions for individual user with minimal possible energy use. The LowEx system was tested in a model room for burn patient and compared with the conventional one. Thermal comfort conditions were simulated for three individual users (burn patient, healthcare worker and visitor) energy use was measured. In a simulation, users were exposed to the required conditions for burn patient created with both systems. The LowEx system creates optimal conditions for burn patient with lower human body exergy consumption (hbExC) rate valid for thermoregulation, minimal evaporation, radiation and convection. For healthcare worker and visitor, the LowEx system creates individual thermal comfort zones. For the LowEx system, the measured energy use for heating was 11–27% lower and for cooling 32–73% lower than for the conventional system.

Keywords: hospital environment; individualised climate; low exergy systems; thermal comfort; human body exergy balance.

126 M. Dovjak et al.

Reference to this paper should be made as follows: Dovjak, M., Shukuya, M. and Krainer, A. (2014) ‘Individualisation of personal space in hospital environment’, Int. J. Exergy, Vol. 14, No. 2, pp.125–155.

Biographical notes: Mateja Dovjak is an Assistant at the Chair for Buildings and Construction Complexes, Faculty of Civil and Geodetic Engineering and at the Faculty for Health Studies, University of Ljubljana. She graduated from the Faculty for Health Studies, University of Ljubljana in 2006 and obtained her PhD from the School of Environmental Sciences, University of Nova Gorica in 2012. She is a member of International Solar Energy Society, ISES – Slovenia and the research group KSKE and COST action C24 (Analysis and design of innovative systems with LowEx for application in built environment, CosteXergy).

Masanori Shukuya is a Professor at the Faculty of Environmental and Information Studies, Tokyo City University (FEIS-TCU) and is also a Professor at and Chairman of the Graduate Programme for Environmental and Information Studies. He has been actively involved in international research cooperation, including participation in the International Energy Agency (IEA) and Energy Conservation in Buildings and Community Systems (ECBCS) and others. He was an Otto-Mønsted Visiting Professor at the Technical University of Denmark in 2008 and 2009.

Aleš Krainer, BSc in Architecture, PhD in Technical Sciences, Scientific Counsellor and Professor at the Faculty of Civil and Geodetic Engineering (FGG UL) and at the Faculty for Health Studies, University of Ljubljana. He is leading R&D projects in Slovenia and EU in RUE and RES from 1980 (COST C24 COSTeXergy, 2007–2009). Member of Standing Committee of Building Physics Professors at European Universities, of ‘Development Group for Environment and Civil Engineering’, Council for Competition, Government Office for Growth and of ‘Expert Council for EPBD’, Ministry for Environment and Spatial Planning, RS, Chairman of ISES – Slovenian section, Chairman of EuroSun’98.

This paper is a revised and expanded version of a paper entitled Building ‘Efficiency: a cross-section of comfort, system performance and energy use’ presented at Clima 2013 Congress, 11th REHVA World Congress, 8th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings, Prague, Czech Republic, 16–19 June, 2013.

1 Introduction

Hospital presents a highly demanding indoor environment that should be treated as a three-dimensional system of users, environmental factors and specific activities. In hospital environment (HE), various users are present (patients, staff and visitors) with different demands and needs (Balaras et al., 2007; Skoog et al., 2005; Skoog, 2006, Dovjak, 2012). Conventional heating, ventilation and air-conditioning (HVAC) systems are designed in most cases as interventions in active spaces, based on the requirements of an average user, and are not suitable for the selected individual user. To fulfil specific individual requirements, new systems are needed.

Individual climate has already been introduced in cars. Local ventilation is used in working environments with positive impact on productivity (Melikov et al., 2002).

Individualisation of personal space in hospital environment 127

However, overall individualisation of personal space that would enable individual generation and control of all factors of environmental ergonomics has not been implemented yet, either as an idea or as a prototype in a test or real environment (Dovjak et al., 2006, 2010a, 2011a, 2012a; Dovjak, 2012).

Highly energy demanding activities in HE, less-efficient HVAC systems and poorly designed building envelope lead to high-energy use and deteriorated air quality. Data from General Directorate for Energy and Transport of European Commission (OPET, 2007) show that average heating energy use in the EU-25 hospitals is 1.523 GJ/m2a and exceeds the average building heating energy use in EU-25 by 59%.

The purpose of the paper is to test a heating and cooling (H/C) system that enables to create optimal conditions for individual user and at the same time minimal possible energy use for H/C of buildings. The H/C system is compared with conventional one regarding simulation of individual thermal comfort conditions and measurements of energy use. For the purpose of our paper, exergy concept was introduced that jointly treats processes inside the human body and processes in a building.

2 Background

2.1 Energy use in hospitals

In EU-25 hospitals, annual energy use is 1.15–1.66 GJ/(m2a) and maximal 2.38 GJ/(m2a) as presented in the General Directorate for Energy and Transport of European Commission report (OPET, 2007).

Annual energy use for heating is 360–486 MJ/(m2a) (oil, gas), ventilation 14.4–198 MJ/(m2a), climatic systems use 18–50.4 MJ/(m2a) (electricity), HVAC systems use 540–734.4 MJ/(m2a), lighting 122.4–140.4 MJ/(m2a) and sanitary water 216–324 MJ/(m2a). Other uses (lifts, cooking and incinerator) represent 266.4–442.8 MJ/(m2a). Overall energy use in hospitals in EU-25 is 385.2–540 TJ/a. It is worth mentioning that the estimated energy-saving potential is between 20% and 45%, which comes up to 75.6–244.8 TJ/a. Energy potential with HVAC technologies could be 36–108 TJ/a, and with building envelope 25.2–79.2 TJ/a (OPET, 2007).

In the majority of hospitals, conventional H/C systems are used. However, LowEx active systems are also available on the market. LowEx systems perform as heating or cooling systems and operate with temperatures closer to the required room temperatures; they can use renewable energy sources. According to the literature (Hepbasli, 2012; IEA ECBCS, 2003; Ljubenko et al., 2011; Meggers and Leibundgut, 2012; Poredoš and Kitanovski, 2002; Schmidt, 2012), there are many different LowEx technologies available, classified as surface H/C systems, air H/C systems, generation/conversion of cold and heat, thermal storage and distribution systems.

Comprehensive literature review by Hepbasli (2012) showed that the exergy efficiency values of the LowEx H/C systems for buildings ranged from 0.40% to 25.3%, whereas those for greenhouses varied between 0.11 and 11.5%. Exergy efficiency depends on the reference state temperatures; lower supply and return temperatures increase the exergy efficiency of the heat supply (Hepbasli, 2012; Torio and Schmidt, 2010).

This paper is focused on surface H/C systems and H/C radiative panels. H/C radiative panels have been applied into numerous public and residential buildings. Their main

128 M. Dovjak et al.

advantages compared with conventional systems are improvement of thermal comfort conditions (Dijk et al., 1998; Dongen, 1985; Dovjak et al., 2010a, 2010b, 2011a, 2011b, 2012a, 2012b; Dovjak, 2012; Fort, 1995; IEA ECBCS, 2003; Košir et al., 2010; Krainer et al., 2007; Olesen, 2008; Skov and Valbjørn, 1990; Zöllner, 1985), decrease in energy use for H/C of buildings (Dijk et al., 1998; Dovjak et al., 2010a, 2010b, 2011a, 2011b, 2012a, 2012b; IEA ECBCS, 2003; Košir et al., 2010; Krainer et al., 2007; Olesen, 2008) and better indoor air quality (IEA ECBCS, 2003; Curtis, 2008; Sammaljarvi, 1998; Schata et al., 1990). H/C radiative panels also enable effective cleaning and maintenance and lower microbiological risk (Legionella in split system with indoor unit) (Curtis, 2008). Despite numerous advantages, there exist only a few studies about radiative panels applied into hospitals (Senuma, 1998).

2.2 Exergy concept in built environment and its relation to thermal comfort

The exergy concept can be derived from two fundamental concepts, energy and entropy, and the concept of the environmental temperature. The term exergy was defined by Zoran Rant from the Faculty of Mechanical Engineering, University of Ljubljana, in 1955. It presents a maximum work obtainable from energy (Rant, 1955). The use of exergy concept in the built environment related to thermal comfort is still relatively new (Isawa et al., 2003; Shukuya and Hammache, 2002; Shukuya et al., 2003; Shukuya, 2009). It enables us to make connections between processes inside the human body and processes in a building (Shukuya and Hammache, 2002), and in such way to create healthy and comfort conditions.

Exergy analyses of thermal comfort conditions (Isawa et al., 2003; Prek, 2004; Prek and Butala, 2010; Shukuya, 2006, 2009) have proven that higher mean radiant temperature (Tmr) and lower room air temperature (Tai) can result in more acceptable comfort conditions. This coincides with the fact that thermally comfortable conditions equal to thermal neutrality seem to lead to lower hbExC rate. Simone et al. (2011) studied the relation between the hbExC rate and the human thermal sensation. Results (Simone et al., 2011) showed that the minimum hbExC rate was related to the thermal sensation votes close to thermal neutrality, tending to slightly cooler side of thermal sensation. The whole human body exergy balance (hbExB) under typical summer conditions in hot and humid regions was analysed by Iwamatsu and Asada (2009) and Shukuya et al. (2010). Tokunaga and Shukuya (2011) investigated the hbExB calculation under unsteady state conditions. Schweiker and Shukuya (2012a) compared predicted mean vote (PMV) approach, adaptive comfort model and calculation of hbExC rate. Prek and Butala (2012) investigated the exergy-based correlation between thermal comfort and the thermal environment. The exergetic aspect of daylighting together with luminous and thermal comfort aspects was discussed in the study by Maki and Shukuya (2012). Schweiker and Shukuya (2012b) performed a study on the effect of preference of using air-conditioning on the exergy consumption pattern within a built environment.

2.3 Individual differences in perception of thermal comfort conditions

Man as a physiological, sociological and psychological being is daily liable to a large number of needs. The needs arise as a result of some imbalances inside of the human body or owing to other outside factors (Musek and Pečjak, 2001). As soon as the need arises, the aspiration for its fulfilment appears (Musek and Pečjak, 2001). Needs can be

Individualisation of personal space in hospital environment 129

fulfilled instinctively or socialised. Moreover, the physiological needs can be fulfilled with the mechanism of homeostasis or progressively (Musek and Pečjak, 2001). The US psychologist Abraham Maslow proposed a theory called Maslow’s hierarchy of needs, where needs are listed in the shape of a pyramid. The largest and most fundamental psychological needs (i.e., breathing, food, water, sleep, homeostasis, avoiding pain, sexuality, etc.) are positioned at the bottom level and the psychological needs (safety, love, belonging, esteem and self-actualisation) are positioned at higher levels. Maslow’s theory suggests that the most basic level of needs must be met before an individual will strongly desire (or focus motivation upon) the secondary- or higher-level needs (Maslow, 1943).

Therefore, environmental parameters of the thermal comfort present one of the basic physiological needs in Maslow’s hierarchy of needs (Maslow, 1943). Their satisfaction is necessary for the state of homeostasis of the human body. Consequently, the main guidance for the design of built environment is the creation of healthy and comfortable conditions for every individual (Dovjak, 2012; Regulation EU 305/2011, 2001; Preamble WHO, 1946). A human being’s thermal sensation is influenced by metabolic rate and clothing, as well as the environmental parameters (air temperature, mean radiant temperature, air velocity and air humidity) (Fanger, 1970; ISO, 2005), individual characteristics (gender differences, anthropometric characteristics and cultural differences) and health status (Dovjak et al., 2010a, 2011a, 2012a; Dovjak, 2012; Hwang et al., 2007). A significant effect of gender, age, acclimatisation and health status on individual perception of thermal comfort conditions has also been proven by studies in hospitals (Hwang et al., 2007; Martin et al., 1992; Parsons, 2002; Pourshaghaghy and Omidvari, 2012; Silverman et al., 1958; Skoog et al., 2005; Skoog, 2006; Verheyena et al., 2011; Wallace et al., 1994).

Metabolic rates mainly change according to occupation or activity, work equipment, work speed, work technique and skill, as well as environmental conditions and individual variability. For the same work under the same working conditions, metabolic rate can vary from person to person by about 5% (ISO, 2004). Skoog et al. (2005) found out that mean measured values for staff in administrative ward are 2.5 met (144 W/m2) during summer and 2.0 met (115 W/m2) during winter. Mean measured values for patients in orthopaedic ward are 1.1 met (66 W/m2) during summer and 1.3 met (78 W/m2) during winter. Metabolic rate is also affected by health status. For example, significant injuries and multiple traumas to the body, long bone fractures or infections, sepsis, surgery, steroid therapy, bone marrow transplants and hyperthyroidism often lead to a condition with abnormal increase in the body’s basal metabolic rate (i.e., hypermetabolism). After burn injury, metabolic rate is increased up to about 150% of basal metabolic rate, when the burn size is greater than 20–30% of the total body size area (TBSA) (Atiyeh et al., 2008; Hart et al., 2003; Jeschke et al., 2007; Herndon and Tompkins, 2004; Wallace et al., 1994; Wilmore et al., 1975). On the other hand, a condition with abnormal decrease in the body’s basal metabolic rate (i.e., hypometabolism) usually occurs in chronically starved persons and patients with hypothyroidism.

Clothing has a direct impact on personnel’s perception of thermal comfort. Skoog et al. (2005) showed that mean measured clo values of staff in administrative ward are 0.57 clo during summer and 0.61 clo during winter. Mean measured clo values of patients in orthopaedic ward are 0.52 clo during summer and 0.64 clo during winter (Skoog et al., 2005). Because of different effective clothing insulation, the preferable thermal comfort conditions differ among anaesthetists (23–24°C), nurses (22–24.5°C)

130 M. Dovjak et al.

and surgeons 18–19°C (Balaras et al., 2007). In general, thermal comfort can be easily regulated by user itself, with clothing. Nevertheless, in specific HE, this is limited, because hygienic demands define types of clothing. Experiments by Zwolińska and Bogdan (2012) showed that surgical clothing, characterised by high insulation and impermeability, was used owing to hygienic reasons; but in combination with high metabolic rate of surgeons, it presented an important factor for thermal stress. The type of clothing fabric may also have effects on airborne bacteria contamination. Whyte et al. (1990) demonstrated that polyester surgical clothing was much superior to conventional cotton clothing and at least as good as the total-body exhaust gowns and disposable clothing.

Environmental parameters, such as Tai and relative humidity (RHin), are important not only from the aspect of thermal comfort but also for healthcare and treatment of patients. Hwang et al. (2007) concluded that patients required warmer indoor environment than healthy population. The required temperature varies owing to specifics of the type of ward facility. For example, a ward for severe burn injuries should have temperature controls that permit adjusting Tai up to 32°C and RHin up to 95% (ASHRAE, 2007). The reason is that patients with large burn injuries have higher risk of hypermetabolism, hypothermia, higher evaporative water losses, progressive weight loss, increased susceptibility to infection and poor wound healing (Atiyeh et al., 2008; Caldwell et al., 1992; Carlson et al., 1992; Corallo et al., 2007; Hart et al., 2003; Herndon, 1996; Herndon and Tompkins, 2004; Jeschke et al., 2007; Kelemen et al., 1996; Martin et al., 1992; Ramos et al., 2002; Wallace et al., 1994; Wilmore et al., 1975). To decrease energy demands, minimise metabolic expenditure and decrease the hypermetabolic response to thermal injury and evaporative water losses, Tai and RHin should be maintained at 28–33°C and 80%, respectively. Mortality, morbidity and hospitalisation can be significantly decreased (Herndon, 1996; Wilmore et al., 1975).

Newborns present another example of specific group with special needs and demands for thermal comfort. Newborns have four times greater heat loss compared with the same unit of body weight than adults (Brück, 1961), and require much higher Tai. Consequently, operative environmental temperature (To) needed to provide thermal neutrality for a healthy baby nursed naked in draft-free surroundings of uniform temperature and moderate humidity after birth is in the range from 35°C (for 1 kg birth weight) to 32°C (more than 2.5 kg of birth weight) (Hey and Katz, 1970).

Special temperature requirements are also defined according to the type of the surgical procedure. For cardiac surgery 17°C, for corneal surgery 18–24°C and for paediatric surgeries 30°C are required (ASHRAE, 2007). The required conditions for patients do not also present thermally comfortable conditions for healthcare workers and may affect their productivity. Pilcher et al. (2002) found out that exposure to Tai lower than 21°C causes decrements of 5.95% in psychophysiological performance in relation to neutral temperature, while exposure to the temperature range of 21–27°C causes minimal changes in performance (0.8% decrement). The range of 27–32°C causes a 7.5% decrement in performance and the temperature above 32°C a 14.88% decrement. Sudoł–Szopińska and Tarnowski (2007) concluded that exposure to temperature below 10°C or above 32°C within 120 min reduces psychophysical capabilities by approximately 15%.

Besides Tai, surface temperatures also have to be considered owing to their large influence on To. Experiences of architects and engineers working in the field of the

Individualisation of personal space in hospital environment 131

design of internal environments show that during winter higher Tmr and lower Tai can result in thermally comfortable conditions equal to thermal neutrality (Dovjak et al., 2010a; Isawa et al., 2003; Iwamatsu and Asada, 2009; Schweiker and Shukuya, 2012a; Shukuya et al., 2003, 2010; Shukuya, 2009; Simone et al., 2011; Tokunaga and Shukuya, 2011). Thus, the first priority action towards thermal comfort conditions is thermally well-insulated building envelope and the second the application of H/C radiative panels (Dovjak et al., 2010b; Dovjak, 2012). Radiative panels enable to regulate To with combinations between Tai and Tmr (Dovjak et al., 2010a, 2011a; Dovjak, 2012). However, for their efficient application, the required To has to be defined, since the existing standards and guidelines in HE only define the required Tai range owing to the specifics of the occupied space, and not To as perceived temperature.

An important problem related to thermal comfort conditions in HE is dryness of air. Studies by Nordström et al. (1994), Hashiguchi et al. (2008) and Skoog (2006) showed that during summer and winter conditions RHin in HE is often perceived as low. Dryness of air causes complaints about thermal discomfort among staff and patients, such as dry and itchy skin and static electricity. To reduce the number of these complaints, humidification has been introduced (Nordström et al., 1994).

Environmental parameters should not be treated just from the perspective of thermal comfort. They should be discussed much more broadly, on macro-scale (building and systems) and micro-scale (interactive impact among parameters and biological risks). Saha et al. (2010) noted that the increase in certain fungal infections coincided with window closure (windows were closed to protect from local refurbishment work) in the naturally ventilated part of hospital. Following window closure, heat and humidity were sometimes considered excessive by staff especially in the summer months. To manage this problem, extra recycling air-coolers were installed. Thus, the measures instituted to control the risk (window closure, which caused a hot, humid atmosphere and required extra air-coolers) may result in an increased risk of fungal infections instead (Saha et al., 2010).

On the level of design of efficient H/C system, it is important to consider all parameters that affect thermal comfort, all individual needs, and at the same time fulfil hygienic demands and the required conditions for HE. The H/C system shall distinguish the required conditions for patients (healing-oriented conditions, conditions important for their healthcare and treatment) and comfort conditions for staff and visitors. The purpose of our paper was to test a LowEx system for the application in HE. A model room for burn patients with highly demanding environmental conditions for healthcare and treatment was selected for observation. The flexibility of the system was proven also for other potential users (visitors and staff).

3 Methods

3.1 Space geometry and characteristics of H/C systems

A series of experiments was carried out in a real test room (7.5 × 5.0 × 4.0 m3) that presents a model room for burn patient (Figure 1). It is located at the Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana. The room is equipped with a LowEx system and a conventional system with time separation. The LowEx system includes six low-temperature heating and

132 M. Dovjak et al.

high-temperature cooling ceiling radiative panels connected with an integrated control system of internal environment on the basis of fuzzy logic (ICSIE system). Panels are positioned 72 cm under the ceiling and 3.16 m above the floor. For the purpose of our experiment, 9 m2 of ceiling are covered with panels.

Figure 1 Plan of test room with positions of conventional system (oil–filled electric heaters and split system with indoor air conditioning unit) and LowEx system (heating and cooling panels). Marked points present thermocouple sensor positions (S1–S15)

Dimensions of H/C ceiling panels are 125 × 125 cm2. They are constructed of a 10 cm thick polystyrene thermal insulation with engraved pipes for hot or cold water (Figures 2 and 3). The final layer of four panels is a contact stuck 1.25 cm gypsum board, and two panels have stone plates (one is a compact 2 cm marble plate and another composite 12 mm Al–honeycomb with a 3 mm thick stone plate). All panels are fixed with four steel screws into ceiling construction. Panels are connected into H/C system with switch-off valves for every panel separately, and with a pump on thermostatic mixing valve. Switching between hot and cool water entering into the panels is manual.

For the purpose of online monitoring and control of indoor parameters, ICSIE system was used. The ICSIE system was developed by Trobec-Lah (2003) and upgraded by Košir (2008). The methodology for the system’s design was primary developed in aircraft environment and transformed for hospitals (Dovjak et al., 2006; Dovjak, 2012). It enables the control of indoor air temperature, CO2 and illuminance under the influence of outdoor environment and users’ requests. The ICSIE system is divided in three parts: sensor network system, regulation system and actuator system. The basic architecture of the system is presented in Figure 4.

Individualisation of personal space in hospital environment 133

Figure 2 Plan and section of heating and cooling panels. In the plan the grooves for the piping are shown

Figure 3 Heating and cooling panels (see online version for colours)

The selected parameters for monitoring were: Tai, Tao, RHin, RHout, surface temperatures, black globe temperature, temperature of the medium in panels and energy use for H/C. The selected time step was 0.5 s. Thermocouple sensor positions (S1–S15) are presented in Figure 1.

The conventional system includes three oil-filled electric heaters type Heller (230 V–50 Hz, 2000 W) and a split system with indoor unit for cooling. External blocks consist of two cooling aggregates, mounted on the top of the roof of the faculty. Internal block consists of a wall-type room conditioner, mounted on the top of the north wall (indoor A/C unit). Water temperature on the entry valve is 10°C.

134 M. Dovjak et al.

Figure 4 Basic architecture of the ICSIE system

Sensors: Tai – room air temperature, Tao – outdoor air temperature, RHin – relative humidity of indoor air, RHout – relative humidity of outdoor air, ILin1 & ILin2 – internal work plane illumination, ILout – external illumination, CCO2 – concentration of CO2, Irgo – direct solar radiation, Irdo – reflected solar radiation, Wp – wind speed, Wd – wind direction, Pe – precipitation detection, Cheat – energy use for heating, Ccool – energy use for cooling.

Source: Košir (2008)

3.2 Subject characteristics and experimental conditions

Three individual users (burn patient, healthcare worker and visitor) were selected for the simulation of individual thermal comfort conditions. Individual input data and experimental conditions were collected from the relevant literature (ASHRAE, 2007; Atiyeh et al., 2008; Caldwell et al., 1992; Carlson et al., 1992; Corralo et al., 2007; Fanger, 1970; Hart et al., 2003; Herndon, 1996; Herndon and Tompkins, 2004; ISO, 2004, 2005; Jeschke et al., 2007; Kelemen et al., 1996; Martin et al., 1992; Skoog et al., 2005; Ramos et al., 2002; Sudoł–Szopińska and Tarnowski, 2007; Wilmore et al., 1975; Wallace et al., 1994) and are presented in Tables 1–3. From the referred sources, characteristics for a burn patient were chosen: 80% TBSA, hypermetabolic state (2 met), hypothermia (body core temperature Tcr = 35.5°C, skin temperature Tsk = 37.0°C). Tsk and Tcr were constant for the calculations of hbExB for burn patient, and were changeable for visitor and healthcare worker. Tcl was calculated on the basis of experimental conditions.

Individualisation of personal space in hospital environment 135

Table 1 The required conditions for burn patient room equipped with conventional and the LowEx system, references

Reference Requirement

Conventional system ASHRAE (2007) Tai

a has to be up to 32°C db and RHina up to 95%

Herndon (1996) and Wilmore et al. (1975)

Taia and RHin

a should be maintained at 30–33°C and 80%, respectively, in order to decrease energy demands and evaporative heat losses

LowEx system ISO (1998) Other requirements that include Tmr

a, Taia, and individual specifics have to

be defined In our study To

a was introduced and calculated for burn patient (ISO, 1998)

Toa for burn patient is 32°C, it presents our requirement that has to be

attained with the LowEx system RHin

a should be maintained at 80% aTai = room air temperature; RHin = relative humidity of indoor air; Tmr = mean radiant temperature; To = operative temperature.

Table 2 Individual user characteristics

User Tcra [°C] Tsk

a [°C] Tcla [°C]

Metabolic rate [met]

Eff. clo insulation [clo]

Burn patient 35.5 37.0 25.3–37.1 2 0 Healthcare worker 36.8–37.2 29.5–36.8 23.6–36.1 1.1 0.6 Visitor 36.9–38.0 31.9_38.6 23.3–36.4 2 0.6 aTcr = body core temperature; Tsk = skin temperature; Tcl = clothing temperature.

The required conditions were created with both systems. During that time, individual thermal comfort conditions were simulated, while energy use was measured. Individual thermal comfort conditions were analysed using the calculated hbExB, hBExC rate and PMVs index with spreadsheet software developed by Hideo Asada Rev 2010 (Iwamatsu and Asada, 2009; Shukuya et al., 2012). The human body exergy model by Shukuya et al. (2010, 2012) was used for the calculation. The reference environmental temperature (the outdoor environmental temperature, Tao) and the outdoor RHout were assumed to be the same as the indoor Tai and indoor RHin. In the room with the conventional system Tai = Tmr = To and in the room with the LowEx system Tai ≠ Tmr ≠ To were assumed.

Table 3 Experimental conditions

Taia [°C] Tmr

a [°C] RHina [%] va

a [m/s]

15.0–35.0 15.0–35.0 30–96 0.1 aRHin = relative humidity of indoor air; va = air velocity; Tai = room air temperature; Tmr = mean radiant temperature.

136 M. Dovjak et al.

3.3 Human body exergy balance model

Human body can be treated as a bio-chemical system (anabolic and catabolic reactions) as well as thermodynamic system (thermogenesis and thermolysis). All psychological processes inside the human body present exergy–entropy process. Human body as a thermodynamic system consists of the core and the shell, positioned in a test room with the environmental temperature. The core is the central portion of a healthy individual, with its temperature kept almost constant at 37°C, independent of the variations of surrounding temperature and humidity. The shell is the peripheral portion, the temperature of which depends on the variations of the surrounding temperature and humidity and on the level of metabolism. The general form of exergy balance equation for a human body as a system is represented in equation (1) (Shukuya et al., 2010; Shukuya et al., 2012):

[Exergy input] – [Exergy consumption] = [Exergy stored] + [Exergy output]. (1)

The exergy input consists of five components:

• warm exergy generated by metabolism

• warm/cool and wet/dry exergies of the inhaled humid air

• warm and wet exergies of the liquid water generated in the core by metabolism

• warm/cool and wet/dry exergies of the sum of liquid water generated in the shell by metabolism and dry air to let the liquid water disperse

• warm/cool radiant exergy absorbed by the whole skin and clothing surfaces.

The exergy output consists of four components:

• warm and wet exergy contained in the exhaled humid air

• warm/cool and wet/dry exergy contained in the resultant humid air containing the evaporated sweat

• warm/cool radiant exergy discharged from the whole skin and clothing surfaces

• warm/cool exergy transferred by convection from the whole skin and clothing surfaces into surrounding air (Shukuya et al., 2010; Shukuya et al., 2012).

How a subject produces and gives away the heat at different environmental conditions is precisely evaluated with hbExB analysis. To maintain thermally comfortable conditions, it is important that the exergy consumption and stored exergy are at optimal values with a rational combination of exergy input and exergy output. In general, lower hbExC rate results in thermally comfortable conditions (at thermal neutrality, PMV = 0). HbExC rate means the rate of exergy that is consumed only by the process of thermoregulation.

3.4 Defined objectives for the testing phase

The main objectives for the testing of LowEx system are (1–5):

1 to create optimal conditions for healthcare and treatment of burn patient with minimal possible hbExC rate valid for thermoregulation, minimal evaporation, radiation and convection

Individualisation of personal space in hospital environment 137

2 to create individual thermal comfort zones for healthcare worker and visitor

3 to create optimal conditions for burn patient, thermal comfort conditions for healthcare worker and visitor and minimal energy use for H/C in the test room at the same time

4 to achieve active regulation of separate parts of hbExB by setting the LowEx system

5 to compare the LowEx system with conventional one regarding exergy analysis of individual thermal comfort conditions and measured energy use for H/C of the test room.

4 Results

The conventional system (Tmr = 32°C, Tai = 32°C, RHin = 80%) and the LowEx system (Tmr = 31°C, Tai = 35°C, RHin = 80%) assure the required conditions for burn patient. The exergy analysis of individual thermal comfort conditions and the measured energy use for H/C are used to compare the performance of the two systems.

4.1 Exergy analysis of individual thermal comfort conditions

Calculated values of HbExB, hbExC rate and PMV index are used for the analyses of individual thermal comfort conditions. The whole hbExB for burn patient exposed to the required conditions created with the conventional system (Tmr = 32°C, Tai = 32°C, RHin = 80%) is presented in Figure 5.

In case of burn patient, input exergy presents thermal radiative exergy exchange between the patient’s body and the surrounding surfaces of the test room, which influences the thermal comfort. Cool/warm radiant exergy absorbed by the whole skin and clothing surfaces is zero, because Tai (=Tao) is equal to Tmr. The sum of exergies contained by the inhaled humid air is also zero (breath air in Figure 5), because room Tai and RHin are equal to outside conditions Tao and RHout. Cool/warm convective exergy absorbed by the whole skin and clothing surfaces is zero, because Tai is equal to Tao, and even Tcl is higher than Tai. The main input exergy (100%) is represented by metabolic thermal exergy (in. part in Figure 5). This means that 2.29 W/m2 of thermal exergy is generated by bio-chemical reactions inside the human body. It is important to keep the body structure functioning and to get rid of the generated entropy. Thus, 2.29 W/m2 have to be released into ambient environmental space by radiation, convection, evaporation and conduction, presenting output exergies. Warm exergy stored in the core and in the shell is 6 mW/m2 and presents a part of metabolic thermal exergy. Because the moisture contained in the room air is not saturated, the water secreted from sweat glands evaporates into the ambient environmental space. Exhalation and evaporation of sweat

represent 0.05 W/m2 (2.2% of output exergies and consumed exergy). Warm radiant exergy discharged from the whole skin and clothing surfaces emerges because of higher Tcl than Tai, and presents 0.12 W/m2 (5.3%). Exergy of 0.32 W/m2 (14.0%) is transferred by convection from the whole skin and clothing surfaces into the surrounding air, mainly owing to the difference between Tcl and Tai. The hbExC rate that presents the difference between exergy input, exergy stored and exergy output is 1.79 W/m2 (78.5%) for conditions created with the conventional system.

138 M. Dovjak et al.

Figure 5 Human body exergy balance for burn patient exposed to required conditions created with conventional system (Tmr = 32°C, Tai = 32°C, RHin = 80%)

A/C – air conditioning, breath air – sum of exergies contained by the inhaled humid air, C/W conv – cool/warm convective exergy absorbed by/discharged from the whole skin and clothing surfaces, C/W rad – cool/warm radiant exergy absorbed by/discharged from the whole skin and clothing surfaces, H/C – heating/cooling, hBExC – human body exergy consumption, in.part – metabolic thermal exergy, PMV – predicted mean vote index, RHin – relative humidity of indoor air, stored – stored exergy in the core and in the shell, sweat – exhalation and evaporation of sweat, Tai – room air temperature, Tcl – clothing temperature, Tcr – body core temperature, Tmr – mean radiant temperature, Tsk – skin temperature. Reference environmental temperature and relative humidity are equal to those of room air, i.e., Tao = Tai and RHin = RHout, respectively.

If a burn patient was exposed to the conditions created with the LowEx system (Tai = 35°C, Tmr = 31°C, RHin = 80%), the input exergies, output exergies and exergy consumption would differ (Figures 5 and 6). Higher Tai and lower Tmr compared with the conditions created with the conventional system cause lower input exergies by metabolic thermal exergy (1.30 W/m2, 95.0% of input exergies). Also, in case of the LowEx system, the metabolic thermal exergy does not present the only input exergy. Cool radiant exergy absorbed by the whole skin and clothing surface is 0.07 W/m2 (5.0%), because Tmr is lower than Tai. Cool/warm convective exergy absorbed by the whole skin and clothing surfaces is zero, because Tai is equal to Tao. Output exergies are warm exergy transferred by convection from the whole skin and clothing surfaces into the surrounding air, warm radiant exergy discharged from the whole skin and clothing surfaces and exhalation and evaporation of sweat. Conditions with lower Tmr than Tai result in lower warm radiant exergy discharged from the whole skin and clothing surfaces (0.01 W/m2, 0.7%), in lower warm exergy transferred by convection (0.03 W/m2, 2.1%), and in lower exhalation and evaporation of sweat (0.02 W/m2, 1.4% of output exergies and consumed exergy).

Individualisation of personal space in hospital environment 139

These values are lower mainly owing to smaller differences between Tcl and Tai, Tcr and Tai than in case of the conventional system. However, lower input exergy consequently results in lower hbExC rate in case of the conventional system (1.36 W/m2, 95.8%). PMV index is higher in case of the LowEx system (less acceptable comfortable environment), but the calculation of PMV index is more relevant for healthy users (healthcare worker and visitor) and not for specific subjects such as for burn patients.

Figure 6 Human body exergy balance for burn patient exposed to required conditions created with the LowEx system (Tmr = 31°C, Tai = 35°C, RHin = 80%)

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

The required conditions for burn patient room are not thermally comfortable for healthcare worker and visitor at either of the systems (PMV ≠ 0) (Figure 7). The results of the whole hbExB show that the hBExC rates are different for healthcare worker and visitor in both systems. Healthcare worker has lower hbExC rate in the room with the LowEx system because of lower input exergies and higher stored exergy. The stored exergy in the core and in the shell presents part of metabolic thermal exergy and is mainly influenced by the differences between Tai and Tcr and Tai and Tsk. Higher stored exergy appears owing to smaller differences between Tai and Tcr and Tai and Tsk. Lower input exergies appear owing to lower metabolic thermal exergy (mainly because of smaller difference between Tai and Tcr and smaller difference between Tai and Tsk) and owing to cool radiation (Tmr < Tai). Lower output exergies appear owing to lower values of radiation, convention, exhalation and evaporation of sweat (mainly because of smaller differences between Tcr and Tai, Tcl and Tai).

140 M. Dovjak et al.

There is a similar situation in the case of the visitor in conditions created with the LowEx system. The result is lower hbExC rate owing to lower input exergies, higher stored exergy and lower output exergies.

Lower input appears owing to lower value of metabolic thermal exergy (mainly because of smaller differences between Tcr and Tai, Tsk and Tai) and owing to cool radiation (Tmr < Tai). Lower output exergies appear owing to lower values of radiation, convection, evaporation and exhalation of sweat (mainly because of smaller differences between Tcr and Tai, Tcl and Tai).

Figure 7 Individual thermal comfort conditions in the room with conventional system (left) and in the one with the LowEx system (right)

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

4.2 Measured energy use for heating and cooling

Energy use was measured for the same space equipped with the LowEx and the conventional system in different periods, owing to the specifics of HE. Energy use for heating was measured during winter period (5–23 March 2010, 447 heating hours) and summer period (18–24 June 2010, 81 heating hours), altogether 528 heating hours. Energy use for cooling was measured for summer period 10–24 June 2010 and 5–10 July 2010, altogether 453 cooling hours. Approximately, the same conditions were selected for the system comparison (equal set-point T, time period, Tao and Tai vary between systems ±1.0 K; 0.8% assumed error) (Table 4).

The measured energy for heating was by 11–27% (0.32–0.36 MJ) lower in the case of the LowEx system compared with the conventional system and by 32–73% (0.61–3.13 MJ) lower in the case of the energy used for cooling.

The overall energy use for the whole measured cooling period (453 cooling hours) was 518 MJ (1.15 MJ average energy use per cooling hour) for the LowEx system and 1314 MJ (2.90 MJ average energy use per cooling hour) for the conventional system. This efficiency of the LowEx system depends on the area of the ceiling (25%) that is activated for H/C. The calculated energy use for heating in case of four times larger surface area of panels was by 40% lower compared with the conventional system.

Individualisation of personal space in hospital environment 141

4.3 Active regulation of thermal comfort zones

The required conditions for burn patient room do not present thermally comfortable conditions for healthcare worker and visitor. The LowEx system could provide special zones for the individual user (Figure 8). For healthcare worker and visitor, individual comfort zones equal to thermal neutrality can be assured (PMV = 0), while for burn patient special zone with required conditions, which have influence on healthcare and treatment, can be created separately.

HbExB can be actively regulated by setting the LowEx system in the selected zones to such combination of Tai, Tmr and RHin (set-up parameters in ICSIE system) that results in optimal hbExB. Compared with the conditions created with the conventional system, the LowEx system with Tai = 35°C, Tmr = 31°C and RHin = 80% in the zone for burn patient results in minimal possible hbExC rate valid for thermoregulation (1.36 W/m2), minimal evaporation and exhalation of sweat (0.02 W/m2), warm radiation (0.01 W/m2) and warm convection (0.03 W/m2).

The LowEx system with Tai = 18°C, Tmr = 27°C and RHin = 60% in the zone for healthcare worker results in thermally comfortable conditions equal to thermal neutrality (PMV = 0) and 2.23 W/m2 hbExC rate. In the case of visitor, neutral thermal comfort conditions (PMV = 0) and hbExC rate 5.65 W/m2 can be created by setting up the LowEx system to Tai = 17°C, Tmr = 25°C and RHin = 60%. Exergy consumption and stored exergy must have optimal values with rational combination of exergy inputs and outputs to maintain comfort conditions for healthcare worker and visitor or the required conditions for burn patient.

Table 4 Measured energy use for heating and cooling [MJ], conventional system, LowEx system

H/C system Energy use [MJ] Tao [°C] Tai [°C]

Conventional system H wintera 2.95 –2.6 23.7 H summerb 1.33 13.2 25.4 C summerc 1.90 18.2 24.7 C summerc 4.32 30.0 25.4 LowEx system H wintera 2.63 –2.6 23.3 H summerb 0.97 13.5 25.5 C summerc 1.29 18.6 25.5 C summerc 1.19 30.0 25.4

aH winter: heating during winter period (447 heating hours). bH summer: heating during summer period (81 heating hours). cC summer: cooling during summer period (453 cooling hours).

142 M. Dovjak et al.

5 Discussion

Regulations and recommendations for HE define requirements for Tai and RHin that are useful for the room equipped with the conventional system. For the room with the LowEx system, other requirements that include Tmr, Tai and parameters connected with the individual user have to be defined. For this purpose, To was introduced and presents the required condition in the room with the LowEx system (To = 32°C, RHin = 80%). In the room with the conventional system, the required conditions are Tai = Tmr = 32°C and RHin = 80%.

Figure 8 Burn patient’s zone with required conditions and thermal comfort zones for visitor and healthcare worker

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

In case of the LowEx system, the required To = 32°C can be attained with a set of combinations between Tmr and Tai (set-up temperature in ICSIE system). In case of conventional system, To is equal to Tmr and Tai (32°C), and cannot be regulated. Figure 9 presents the hbExC rate as a function of To in the room with the LowEx system (RHin = 80%) for three individual users. Solid line presents the required To = 32°C, which can be attained with a set of combinations between Tai and Tmr, i.e., Tai = 35°C and Tmr = 31°C; Tai = 26°C and Tmr = 35°C, etc. These combinations result in different hbExC rates (Figure 9, encircled part: from 1.4 W/m2 to 2.4 W/m2 for burn patient; from 1.0 W/m2 to 2.3 W/m2 for healthcare worker; from 1.7 W/m2 to 4.4 W/m2 for visitor) and also in different hbExB (Table 5, Figure 10). This approach gives us a new possibility of active regulation of the hbExC rates, as well as separate parts of hbExB, as it was presented in Section 4.

Individualisation of personal space in hospital environment 143

In case of the conventional system, the required Tai = 32°C (solid line) results in only one value of the hbExC rate (1.8 W/m2 for burn patient, 1.5 W/m2 for healthcare worker and 2.7 W/m2 for visitor) (Figure 11) and fixed hbExB (Table 6, Figure 12). This is why active regulation of the hbExC rates and hbExB with a set of combinations between Tai and Tmr is not possible with the conventional system.

For burn patient, it is important to create conditions, which result in minimal hbExC rate valid for thermoregulation, besides minimal possible metabolic thermal exergy rate, radiation, convection and evaporation (healing-oriented conditions). The same conclusions were made by Caldwell et al. (1992), Herndon and Tompkins (2004), Kelemen et al. (1996), Marin et al. (1992), Wallace et al. (1994) and Wilmore et al. (1975). Figure 13 presents the hbExC rate for burn patient, as a function of Tai(= Tmr) and RHin, for conditions created with the conventional system. The black line presents the rate of thermal load on the body surface area ( 0,L = PMV = 0). The minimal possible hbExC rate (0.17 W/m2) can be found at the conditions with Tai = 35°C and RHin = 96% and the maximal possible hbExC rate (7.17 W/m2) at Tai = 35°C and RHin = 30%. All conditions that result in high hBExC rate, high metabolic thermal exergy, radiation, convection and evaporation have to be avoided. The same conclusions were made by Wilmore et al. (1975) and Herndon (1981). Wilmore et al. (1975) found out that hypermetabolism can be attenuated by increasing the ambient temperature from 25°C to 33°C. Herndon (1981) concluded that metabolic rate is the lowest possible at an ambient temperature of 35°C. In these two studies, only the air temperature was taken into consideration, neglecting RHin.

Figure 9 Human body exergy consumption (hbExC) rate [W/m2] as a function of operative temperature (To), LowEx system (80% RHin) (see online version for colours)

Solid line presents the required conditions created in the room with the LowEx system (To = 32°C), encircled part presents hbExC rates for three individual users.

144 M. Dovjak et al.

Figure 10 Human body exergy balances for three individual users exposed to conditions created with the LowEx system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

Table 5 Human body exergy balances for three individual users exposed to conditions created with the LowEx system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

Subject Tset upa

C/Wb radiant

exergy in

C/Wb convective exergy in

Breath air in

From inner part HbExC

Stored exergy

Exhalation, sweat out

C/Wb radiation

out

C/Wb convection

out

Burn patient

Tai = 35°C

Tmr = 31°C

C = 0.07

W = 0

0 0 1.30 1.36 0.001 0.02 C = 0

W = 0.01

C = 0

W = 0.03

Health care worker

Tai = 35°C

Tmr = 31°C

C = 0.13

W = 0

0 0 0.95 1.03 0.04 0.01 C = 0.001

W = 0

C = 0.001

W = 0

Visitor Tai = 35°C

Tmr = 31°C

C = 0.13

W = 0

0 0 1.90 1.72 0.28 0.02 C = 0

W = 0.0001

C = 0

W = 0.0001

Burn patient

Tai = 26°C

Tmr = 35°C

C = 0

W = 0.64

0 0 4.36 2.37 0.006 0.16 C = 0

W = 0.67

C = 0

W = 1.80

Health care worker

Tai = 26°C

Tmr = 35°C

C = 0

W = 0.64

0 0 2.83 2.30 0.004 0.09 C = 0

W = 0.43

C = 0

W = 0.65

Visitor Tai = 26°C

Tmr = 35°C

C = 0

W = 0.64

0 0 5.24 4.40 0.02 0.17 C = 0

W = 0.35

C = 0

W = 0.95 aTset up – set up temperature; Tai – room air temperature; Tmr – mean radiant temperature. bC/W – cool/warm exergy.

A new possibility of active regulation of the hbExC rate, hbExB and thermal comfort conditions with the LowEx system is proposed. Figure 14 presents the hbExC rate for burn patient, as a function of Tai and Tmr (80% RHin), for conditions created with the LowEx system. As can be seen, the minimal and maximal possible hbExC rates could be found in the same temperature conditions as in the room with the conventional system. However, with the LowEx system, we could attain the minimal possible hbExC rate and thermally comfortable conditions equal to thermal neutrality ( 0,L = PMV = 0) with the set of combinations between Tai and Tmr (Figure 14, black spots: Tai = 27°C and

Individualisation of personal space in hospital environment 145

Tmr = 29°C results in 2.0 W/m2; 31°C Tai and 20°C Tmr in 2.7 W/m2; 28°C Tai and 25°C Tmr in 2.1 W/m2). All these conditions result in different hbExB (Table 7, Figure 15). The same approach can be used for other patients, healthcare workers, or visitors, depending on the desired conditions (medical status, or needs for healthy individuals, etc.).

Figure 11 Human body exergy consumption (hbExC) rate [W/m2] as a function of room air temperature (Tai), for the conventional system (80% RHin). Solid line presents the required conditions in the room with the conventional system (Tai = 32°C) (see online version for colours)

Table 6 Human body exergy balances for three individual users exposed to conditions created with the conventional system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

Subject Tset upa

C/Wb radiant

exergy in

C/Wb convective exergy in

Breath air in

From inner part HbExC

Stored exergy

Exhalation, sweat out

C/Wb radiation

out

C/Wb convection

out

Burn patient

Tai = 32°C

Tmr = 32°C

C = 0

W = 0

0 0 2.29 1.79 0.006 0.05 C = 0

W = 0.12

C = 0

W = 0.32

Health care worker

Tai = 32°C

Tmr = 32°C

C = 0

W = 0

0 0 1.63 1.53 0.003 0.03 C = 0

W = 0.03

C = 0

W = 0.04

Visitor Tai = 32°C

Tmr = 32°C

C = 0

W = 0

0 0 3.05 2.68 0.18 0.05 C = 0

W = 0.04

C = 0

W = 0.09 aTset up – set up temperature; Tai – room air temperature; Tmr – mean radiant temperature. bC/W – cool/warm exergy.

To achieve an integral control of all factors of environmental ergonomics, an extensive work from the conceptual to the research and development point of view is required. In addition to the control of physical factors of thermal environment, it is necessary to establish a comprehensive control and prevention of all risk factors in HE (Dovjak, 2012). It is possible to introduce many different technologies and systems inside such space. They can be harmonically adjusted to the hospital specifics.

146 M. Dovjak et al.

The presented system enables the control of thermal comfort, of air quality and of visual and acoustic comfort. At the end, integral individualisation can be achieved (Figure 16) (Dovjak, 2012).

Table 7 Human body exergy balances for burn patient exposed to conditions created with the LowEx system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

Subject Tset upa

C/Wb radiant

exergy in

C/Wb convective exergy in

Breath air in

From inner part hbExC

Stored exergy

Exhalation, sweat out

C/Wb radiation

out

C/Wb convection

out

Burn patient

Tai = 27°C

Tmr = 29°C

W = 0.03

C = 0

0 0 3.79 2.00 0.002 0.14 W = 0.45

C = 0

W = 1.22

Tai = 31°C

Tmr = 20°C

W = 0

C = 0.93

0 0 2.13 2.68 0.001 0.06 W = 0.08

C = 0

W = 0.23

Tai = 28°C

Tmr = 25°C

W = 0

C = 0.07

0 0 3.31 2.14 0.001 0.11 W = 0.31

C = 0

W = 0.82

aTset up – set up temperature; Tai – room air temperature; Tmr – mean radiant temperature. bC/W – cool/warm exergy.

Figure 12 Human body exergy balances for three individual users exposed to conditions created with conventional system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

Individualisation of personal space in hospital environment 147

Figure 13 Human body exergy consumption (hbExC) rate [W/m2], burn patient, Tai(= Tmr) [°C] and RHin [%] for the conventional system (see online version for colours)

The black line presents the rate of thermal load on the body surface area ( 0,L = PMV = 0).

Figure 14 Human body exergy consumption (hbExC) rate [W/m2], burn patient, as a function of Tai and Tmr, 80% RHin, LowEx system (see online version for colours)

The black line presents the rate of thermal load on the body surface area ( 0,L = PMV = 0).

Figure 15 Human body exergy balances for burn patient exposed to conditions created with the LowEx system. Calculated values of exergy inputs, outputs, hbExC and stored exergy are presented as rates [W/m2]

For symbols and abbreviations refer to Figure 5. Reference environmental temperature and relative humidity are equal to those of room air, Tao = Tai and RHin = RHout.

148 M. Dovjak et al.

Figure 16 Individual regulation of factors of environmental ergonomics

6 Conclusions

This study can be considered as a first step towards individualisation of personal space in indoor built environments. On the basis of the consideration of conventional and LowEx H/C systems, the following conclusions can be made:

• Highly demanding activities, individual differences in perception of thermal comfort conditions and high-energy use for H/C of hospitals, lead to the need for the design of new H/C systems and their application in HE.

• The purposed Low Ex system satisfies individual user needs, supports healthcare and treatment, minimises or eliminates health hazards, and fulfils all regulated demands for HE.

• The analysis of hbExB enables to evaluate more precisely how a subject produces and gives away heat depending on different environmental conditions and individual requirements.

• LowEx system creates optimal conditions for healthcare and treatment with lower hbExC rate valid for thermoregulation, minimal evaporation, radiation and convection.

• Since the required conditions for burn patient room do not also present thermally comfortable conditions for healthcare worker and visitor, the LowEx system could enable the creation of special zones for individual user.

• The LowEx system enables to actively regulate separate parts of hbExB by setting Tai and Tmr.

• The measured energy use for heating was in the presented case by 11–27% lower for the LowEx system than for the conventional system. The energy use for cooling was by 32–73% lower for the LowEx system. The main reasons for lower energy use

Individualisation of personal space in hospital environment 149

are lower temperature difference between cooling or heating media inside panels and higher surface area in comparison with the conventional system.

• The LowEx system enables control of all factors of environmental ergonomics.

Acknowledgements

The research was supported by the Research Programme Building Construction and Building Physics, University of Ljubljana, Faculty of Civil and Geodetic Engineering by the Ministry of Higher Education, Science and Technology, Republic of Slovenia and COST action C24 Analysis and design of innovative systems with LowEx for application in built environment, CosteXergy.

References American Society for Heating, Refrigerating and Air–Conditioning Engineers Handbook

(ASHRAE) (2007) HVAC Applications, Health Care Facilities, ASHRAE, Atlanta. Atiyeh, B.S., Gunn, S.W. and Dibo S.A. (2008) ‘Nutritional and pharmacological modulation of the

metabolic response of severely burned patients: review of the literature (part 3)’, Annals of Burns and Fire Disasters, Vol. 21, No. 4, pp.175–181.

Balaras, C.A., Dascalaki, E. and Gaglia, A. (2007) ‘HVAC and indoor thermal conditions in hospital operating rooms’, Energy and Buildings, Vol. 39, No. 4, pp.454–470.

Brück, K. (1961) ‘Temperature regulation in the newborn infant’, Biology of Neonate, Vol. 3, pp.65–119.

Caldwell, F.T., Wallace, B.H., Cone, J.B. and Manuel, L. (1992) ‘Control of the hypermetabolic response to burn injury using environmental factors’, Annals of Surgery, Vol. 215, No. 5, pp.485–491.

Carlson, D.E., Cioffi, W.G. and Mason, A.D. (1992) ‘Resting energy expenditure in patients with thermal injuries’, Surgery, Gynecology and Obstetrics, Vol. 174, pp.270–276.

Corallo, J., King, B., Pizano, L., Namias, N. and Schulman, C. (2007) ‘Core warming of a burn patient during excision to prevent hypothermia’, Burns, Vol. 34, No. 3, pp.418–420.

Curtis, L.T. (2008) ‘Prevention of hospital acquired infections: review of non–pharmacological interventions’, Journal of Hospital Infection, Vol. 69, No. 3, pp.204–219.

Dijk, H.A.L., Bruchem, L. and Wolveren, J. (1998) Voorstudie naar de effecten en het gedrag van Laag Temperatuur Systemen, University of Technology, Delft.

Dongen, J.E.F. (1985) Ervaringen en gedrag van bewoners in woningen met verschillende verwarmingssystemen: Onderzoek in het demonstratieproject Westenholte te Zwolle, University of Leiden, Leiden.

Dovjak, M. (2012) Individualisation of Personal Space in Hospital Environment, Doctoral Thesis, University of Nova Gorica, Nova Gorica, Slovenia.

Dovjak, M., Asada, H., Iwamatsu, T., Shukuya, M., Olesen, B.W. and Krainer, A. (2011b) ‘Lowex vs conventional systems: User/building/environment’, International Exergy, Life Cycle Assessment and Sustainability Workshop & Symposium, European Cooperation in Science and Technology, Nisyros, Greece, pp.1–8.

Dovjak, M., Krainer, A. and Kristl, Ž. (2006) ‘Individualisation of personal space: aircraft seat’, Energija i okoliš 2006, Hrvatski savez za sunčevu energiju, Rijeka, Croatia, pp.61–70.

Dovjak, M., Kukec, A., Kristl, Ž., Košir, M., Bilban, M., Shukuya, M. and Krainer, A. (2012a) ‘Integral control of health hazards in hospital environment’, Indoor and Built Environment, doi:10.1177/1420326X12459867.

150 M. Dovjak et al.

Dovjak, M., Shukuya, M. and Krainer, A. (2012b) ‘Exergy analysis of conventional and low exergy systems for heating and cooling of near zero energy buildings’, Journal of Mechanical Engineering, Vol. 58, Nos. 7–8, pp.453–461.

Dovjak, M., Shukuya, M., Olesen, B.W. and Krainer, A. (2010a) ‘Innovative design of renewable energy technology systems for heating and cooling in sustainable buildings’, Renewable Energy 2010, Advanced Technology Paths to Global Sustainability, International Solar Energy Society, Yokahama, Japan, pp.1–4.

Dovjak, M., Shukuya, M., Olesen, B.W. and Krainer, A. (2010b) ‘Analysis on exergy consumption patterns for space heating in Slovenian buildings’, Energy Policy, Vol. 38, No. 6, pp.2998–3007.

Dovjak, M., Simone, A., Kolarik, J., Asada, H., Iwamatsu, T., Schellen, L., Shukuya, M., Olesen, B.W. and Krainer, A. (2011a) ‘Exergy analysis: the effect of relative humidity, air temperature and effective clothing insulation on thermal comfort’, International Exergy, Life Cycle Assessment and Sustainability Workshop & Symposium, European Cooperation in Science and Technology, Nisyros, Greece, pp.1–8.

Fanger, P.O. (1970) Thermal Comfort: Analysis and Applications in Environmental Engineering, Danish Technical Press, Copenhagen.

Fort, K. (1995) ‘Dynamisches Verhalten von Fussbodenheizsystemen’, 22 International Velta–Kongreß ’95 Velta, Tirol, Austria, pp.65–75.

Hart, D.W., Wolf, S.E., Chinkes, D.L., Beauford, R.B., Mlcak, R.P., Heggers, J.P., Wolfe, R.R. and Herndon, D.N. (2003) ‘Effects of early excision and aggressive enteral feeding on hypermetabolism, catabolism, and sepsis after severe burn’, The Journal of Trauma, Vol. 54, No. 4, pp.755–761.

Hashiguchi, N., Hirakawa, M., Tochihara, Y., Kaji, Y. and Karaki, C. (2008) ‘Effects of setting up of humidifiers on thermal conditions and subjective responses of patients and staff in a hospital during winter’, Applied Ergonomics, Vol. 39, No. 2, pp.158–165.

Hepbasli, A. (2012) ‘Low exergy (LowEx) heating and cooling systems for sustainable buildings and societies’, Renewable and Sustainable Energy Reviews, Vol. 16, pp.73–104.

Herndon, D.N. (1981) ‘Mediators of metabolism’, Journal of Trauma, Vol. 21, pp.701–705. Herndon, D.N. (1996) Total Burn Care, 1st ed., Sunders, London. Herndon, D.N. and Tompkins, R.G. (2004) ‘Support of the metabolic response to burn injury’,

Lancet, Vol. 363, No. 9424, pp.1895–1902. Hey, E.N. and Katz, G. (1970) ‘The optimum thermal environment for naked babies’, Archives of

Disease in Childhood, Vol. 45, No. 241, pp.328–334. Hwang, R.L., Lin, T.P., Cheng, M.J. and Chien, J.H. (2007) ‘Patient thermal comfort requirement

for hospital environments in Taiwan’, Building and Environment, Vol. 42, No. 8, pp.2980–2987.

International Energy Agency, Energy Conservation in Buildings and Community Systems, Annex 37 (IEA ECBCS) (2003) Guidebook to IEA ECBCS Annex 37: Heating and Cooling with Focus on Increased Energy Efficiency and Improved Comfort, Low Exergy Systems for Heating and Cooling, VTT Technical Research Centre, Finland.

International Organization for Standardization (ISO) (1998) ISO 7726:1998: Ergonomics of the Thermal Environment – Instruments for Measuring Physical Quantities, ISO, Geneva.

International Organization for Standardization (ISO) (2004) ISO 8996:2004: Ergonomics of the Thermal Environment Determination of Metabolic Rate, ISO, Geneva.

International Organization for Standardization (ISO) (2005) ISO 7730:2005. Ergonomics of the Thermal Environment – Analytical Determination and Interpretation of Thermal Comfort using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria, ISO, Geneva.

Isawa, K., Komizo, T. and Shukuya, M. (2003) ‘The relationship between human–body exergy consumption rate and a combination of indoor air temperature and mean radiant temperature’, Transactions of Architectural Institute of Japan, Vol. 570, pp.29–35.

Individualisation of personal space in hospital environment 151

Iwamatsu, T. and Asada, H. (2009) A Calculation Tool for Human–Body Exergy Balance, Newsletter No. 6, IEA ECBCS Annex 49, Low exergy systems for high–performance buildings and communities, Fraunhofer Verlag, Stuttgart, Germany, pp.4–5.

Jeschke, M.G., Mlcak, R.P., Finnerty, C.C., Norbury, W.B., Gauglitz, G.G., Kulp, G.A. and Herndon, D.N. (2007) ‘Burn size determines the inflammatory and hypermetabolic response’, Critical Care, Vol. 11, No. 4, p.R90.

Kelemen, J.J., Cioffi, W.G., Mason, A.D., Mozingo, D.W., McManus, W.F. and Pruitt, B.A. (1996) ‘Effect of ambient temperature on metabolic rate after thermal injury’, Annals of Surgery, Vol. 223, pp.406–412.

Košir, M. (2008) Integrated Regulating System of Internal Environment of the Basis of Fuzzy Logic Use, Doctoral Thesis, Faculty of Civil end Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia.

Košir, M., Krainer, A., Dovjak, M., Perdan, R. and Kristl, Ž. (2010) ‘Alternative to the conventional heating and cooling systems in public buildings’, Journal of Mechanical Engineering, Vol. 56, No. 9, pp.575–583.

Krainer, A., Perdan, R. and Krainer, G. (2007) ‘Retrofitting of the Slovene ethnographic museum’, Bauphysik, Vol. 29, No. 5, pp.350–365.

Ljubenko, A., Poredoš, A. and Zager, M. (2011) ‘Effects of hot–water–pipeline renovation in a district heating system’, Journal of Mechanical Engineering, Vol. 57, No. 11, pp.834–847.

Maki, Y. and Shukuya, M. (2012) ‘Visual and thermal comfort and its relations to exergy consumption in a classroom with daylighting’, International Journal of Exergy, Vol. 11, No. 4, pp.481–492.

Martin, C.J., Ferguson, J.C. and Rayner, C. (1992) ‘Environmental conditions for treatment of burned patients by the exposure method’, Burns, Vol. 18, No. 4, pp.273–282.

Maslow, A.H. (1943) ‘A theory of human motivation’, Psychological Review, Vol. 50, No. 4, pp.370–396.

Meggers, F. and Leibundgut, H. (2012) ‘The reference environment: utilising exergy and anergy for buildings’, International Journal of Exergy, Vol. 11, No. 4, pp.423–438.

Melikov, A.K., Cermak, R. and Majer, M. (2002) ‘Personalized ventilation: evaluation of different air terminal devices’, Energy and Buildings, Vol. 34, No. 8, pp.829–836.

Musek, J. and Pečjak, V. (2001) Psychology, Educy, Ljubljana. Nordström, K., Norbäck, D. and Akselsson, R. (1994) ‘Effect of air humidification on the sick

building syndrome and perceived indoor air quality in hospitals: a four month longitudinal study’, Occupational and Environmental Medicine, Vol. 51, No. 10, pp.683–688.

Olesen, B.W. (2008) ‘Radiant floor cooling systems’, ASHRAE Journal, Vol. 9, pp.16–22. OPET (2007) Commission of the European Communities Directorate–General for Energy DG XVII

Energy Efficiency in Hospitals and Clinics, European Commission, Brussels. Parsons, K.C. (2002) ‘The effects of gender, acclimation state, the opportunity to adjust clothing

and physical disability on requirements for thermal comfort’, Energy and Buildings, Vol. 34, No. 6, pp.593–599.

Pilcher, J.J., Nadler, E. and Busch, C. (2002) ‘Effects of hot and cold temperature exposure on performance: a meta–analytic review’, Ergonomics, Vol. 45, No. 10, pp.682–698.

Poredoš, A. and Kitanovski, A. (2002) ‘Exergy loss as a basis for the price of thermal energy’, Energy Conversion and Management, Vol. 43, No. 16, pp.2163–2173.

Pourshaghaghy, A. and Omidvari, M. (2012) ‘Examination of thermal comfort in a hospital using PMV–PPD model’, Applied Ergonomics, Vol. 43, No. 6, pp.1089–1095.

Preamble WHO (1946) Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19–22 June, 1946; signed on 22 July, 1946 by and entered into force on 7 April, 1948. World Health Organisation, New York.

152 M. Dovjak et al.

Prek, M. (2004) ‘Exergy analysis of thermal comfort’, International Journal of Exergy, Vol. 1, No. 2, pp.303–315.

Prek, M. and Butala, V. (2010) ‘Principles of exergy analysis of human heat and mass exchange with the indoor environment’, International Journal of Heat and Mass Transfer, Vol. 3, Nos. 25–26, pp.5806–5814.

Prek, M. and Butala, V. (2012) ‘An enhanced thermal comfort model based on the exergy analysis approach’, International Journal of Exergy, Vol. 10, No. 2, pp.190–208.

Ramos, G.E., Resta, M., Patińo, O., Bolgiani, A.N., Prezzavento, G., Grillo, R., Chacón Pazmińo, G., Benaim, F. and Rutan, R.L. (2002) ‘Peri –operative hypothermia in burn patients subjected to non–extensive surgical procedures’, Annals of Burns and Fire Disasters, Vol. 15, No. 3, pp.1–6.

Rant, Z. (1955) ‘Energy value and pricing’, Journal of Mechanical Engineering, Vol. 1, No. 1, pp.4–7.

Regulation EU 305/2011 (2011) Regulation EU 305/2011 of the European Parliament and of the Council of 9 March 2011 Laying Down Harmonized Conditions for the Marketing of Construction Products and Repealing Council Directive 89/106/EEC, European Commission, Brussels.

Saha, V., Shanson, E., Shankar, A., Samuel, D. and Milla, M. (2010) ‘Hospital ventilation, heat and humidity: risk of fungal and other infections’, Journal of Hospital Infection, Vol. 75, No. 1, pp.74–75.

Sammaljarvi, E. (1998) ‘Heating, indoor dusts, stuffiness and room space electricity as health and well–being risks’, Healthy Buildings Conference ’88, Swedish Council for Building Research, Stockholm, Sweden, pp.697–705.

Schata, M., Elixman, J.H. and Jorde, W. (1990) ‘Evidence of heating systems in controlling house–dust mites and moulds in the indoor environment’, Indoor Air 1990: Proceedings of the 5th International Conference on Indoor Air Quality and Climate, Mortgage and Housing Corp, Toronto, Ontario, Canada, pp.577–586.

Schmidt, D. (2012) ‘Benchmarking of low ‘exergy’ buildings’, International Journal of Exergy, Vol. 11, No. 4, pp.473–480.

Schweiker, M. and Shukuya, M. (2012a) ‘Adaptive comfort from the viewpoint of human body exergy consumption’, Building and Environment, Vol. 51, pp.351–360.

Schweiker, M. and Shukuya, M. (2012b) ‘Study on the effect of preference of air–conditioning usage on the exergy consumption pattern within a built environment ’, International Journal of Exergy, Vol. 11, No. 4, pp.409–422.

Senuma, H. (1998) ‘Experimental operation and indoor thermal environment of the ceiling radiant cooling and heating system’, Building Mechanical and Electrical Engineer, Vol. 6, pp.41–46.

Shukuya, M. (2006) ‘Comfortable high–performance and low–exergy built environment’, International Energy Agency Programme on Energy Conservation in Buildings & Community Systems, IEA ECBCS, Lyon, France, pp.893–898.

Shukuya, M. (2009) ‘Exergy concept and its application to the built environment’, Building and Environment, Vol. 44, No. 7, pp.1545–1550.

Shukuya, M. and Hammache, A. (2002) Introduction to the Concept of Exergy for a Better Understanding of Low–Temperature–Heating and High–Temperature–Cooling Systems. Research Notes 2158, Technical Research Centre of Finland, Vuorimiehenti, Finland, pp.1–61.

Shukuya, M., Iwamatsu, T. and Asada, H. (2012) ‘Development of human-body exergy balance model for a better understanding of thermal comfort in the built environment’, International Journal of Exergy, Vol. 11, No. 4, pp.493–507.

Individualisation of personal space in hospital environment 153

Shukuya, M., Komizo, T. and Isawa, K. (2003) ‘Human–body exergy consumption varying with the combination of room air and mean radiant temperatures’, Journal of Environmental Engineering, Vol. 570, pp.29–35.

Shukuya, M., Saito, M., Isawa, K., Iwamatsu, T. and Asada, H. (2010) Working Report of IEA ECBS: Human Body Exergy Balance and Thermal Comfort, International Energy Agency, Energy Conservation in Buildings and Community Systems, Annex 49, LowExergy systems for high performance systems and communities, Fraunhofer IBP, Germany.

Silverman, W.A., Fertig, J.W. and Berger, A.P. (1958) ‘The influence of thermal environment on survival of newly born premature infant’, Pediatrics, Vol. 22, No. 5, pp.876–886.

Simone, A., Kolarik, J., Iwamatsu, T., Asada, H., Dovjak, M., Schellen, L., Shukuya, M. and Olesen, B.W. (2011) ‘A relation between calculated human body exergy consumption rate and subjectively assessed thermal sensation’, Energy and Buildings, Vol. 43, No. 1, pp.1–9.

Skoog, J. (2006) ‘Relative air humidity in hospital wards–user perception and technical consequences’, Indoor and Built Environment, Vol. 15, No. 1, pp.93–97.

Skoog, J., Fransson, N. and Jagemar, L. (2005) ‘Thermal environment in Swedish hospitals, summer and winter measurements’, Energy and Buildings, Vol. 37, pp.872–877.

Skov, P. and Valbjørn, O. (1990) ‘The Danish town hall study: a one–year follow–up’, Indoor Air 1990: Proceedings of the 5th International Conference on Indoor Air Quality and Climate, Mortgage and Housing Corp, Toronto, Ontario, Canada, pp.787–791.

Sudoł–Szopińska, I. and Tarnowski, W. (2007) ‘Thermal comfort in the operating suite’, New Medicine, Vol. 2, pp.40–46.

Tokunaga, K. and Shukuya, M. (2011) ‘Human–body exergy balance calculation under un–steady state conditions’, Building and Environment, Vol. 46, No. 11, pp.2220–2229.

Torio, H. and Schmidt, D. (2010) ‘Development of system concepts for improving the performance of a waste heat district heating network with exergy analysis’, Energy and Buildings, Vol. 42, pp.1601–1619.

Trobec-Lah, M. (2003) Harmonization of Thermal and Daylight Fluxes with Fuzzy Logic, Doctoral Thesis, Faculty of Civil end Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia.

Verheyena, J., Theysa, N., Allonsiusa, L. and Descampsb, F. (2011) ‘Thermal comfort of patients: Objective and subjective measurements in patient rooms of a Belgian healthcare facility’, Building and Environment, Vol. 46, No. 5, pp.1195–1204.

Wallace, B.H., Caldwell, F.T. and Cone, J.B. (1994) ‘The interrelationships between wound management, thermal stress, energy metabolism, and temperature profiles of patients with burns’, Journal of Burn Care and Rehabilitation, Vol. 15, No. 6, pp.499–508.

Whyte, W., Hamblen, D.L., Kelly, I.G., Hambraeus, A. and Laurell, G. (1990) ‘An investigation of occlusive polyester surgical clothing’, Journal of Hospital Infection, Vol. 15, No. 4, pp.363–374.

Wilmore, D.W., Mason, A.D., Johnson, D.W. and Pruitt, B.A. (1975) ‘Effect of ambient temperature on heat production and heat loss in burn patients’, Journal of Applied Physiology, Vol. 38, No. 4, pp.593–597.

Zöllner, G. (1985) ‘Wärme–abgabe; wärmetechnische prüfung und auslegung von warmwasser–fussbodenheizungen’, Clima 2000: REHVA World Congress, Federation of European Heating and Air–Conditioning Associations, Brussels, pp.341–349.

Zwolińska, M. and Bogdan, A. (2012) ‘Impact of the medical clothing on the thermal stress of surgeons’, Applied Ergonomics, Vol. 43, No. 6, pp.1096–1104.

154 M. Dovjak et al.

Nomenclature

CCO2 Concentration of CO2 [ppm] Ccool Energy use for cooling [MJ, kWh] Cheat Energy use for heating [MJ, kWh] ILin1 and ILin2 Internal work plane illuminance [lx] ILout External illuminance [lx]

Irgo Direct solar radiation [W/m2]

Irdo Reflected solar radiation [W/m2]

L Rate of thermal load on the body surface area [W/m2]

Pe Precipitation detection [–]

RHin Relative humidity of indoor air [%]

RHout Relative humidity of outdoor air [%]

Tai Room air temperature [°C, K]

Tao Outdoor air temperature [°C, K]

Tcl Clothing temperature [°C, K]

Tcr Body core temperature [°C, K]

Tmr Mean radiant temperature [°C, K]

Tset up Set up temperature [°C, K]

Tsk Skin temperature [°C, K]

To Operative temperature [°C, K]

va Air velocity [m/s]

Wp Wind speed [m/s]

Wd Wind direction [°] Abbreviations A/C Air conditioning breath air Sum of exergies contained by the inhaled humid air C/W Cool/warm exergy C/W conv Cool/warm convective exergy absorbed by/discharged from the whole skin and

clothing surfaces C/W rad Cool/warm radiant exergy absorbed by/discharged from the whole skin and

clothing surfaces hbExC Human body exergy consumption hbExB Human body exergy balance H/C Heating/cooling HE Hospital environment HVAC Heating, Ventilation and Air–Conditioning ICSIE Integrated control system of internal environment on the basis of fuzzy logic in.part Metabolic thermal exergy LowEx Low exergy system PMV Predicted mean vote index

Individualisation of personal space in hospital environment 155

S1–S15 Thermocouple sensor positions Stored Stored exergy in the core and in the shell sweat Exhalation and evaporation of sweat TBSA Total body size area

View publication statsView publication stats