individualised climate in future buildings. fact or...

Individualised climate in future buildings. Fact or fiction?

Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia

Tokyo City University, Laboratory of Building Environment, Yokohama, Japan

Mateja Dovjak*,Masanori Shukuya, Aleš Krainer

*Corresponding email: [email protected]

Vienna, 9-11 September 2013

ProblemIn

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Environmental factors

Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

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factors

Specific activities

ProblemIn

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gs• Current HVAC systems are not designed on the

requirements of individual users � dissatisfaction, ↓productivity, ↑ energy use for H/C purposes (Pheasant 1991).

• Selkowitz, Lawrence Berkeley Lab: energy costs presents $21.53 per m2 per year, and people cost about $23174.67 per m2 (Peyton 1999).


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about $23174.67 per m2 (Peyton 1999).

• Even a small improvement in productivity and reduction in absenteeism are more worthy than any energy savings.

PurposeIn

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gs• To design + test a user–centred H/C system that

enables to create optimal conditions for individual user + minimal possible energy use for H/C of residential buildings.

• Flexibility of the system was proven on specific users of the space as well as for various activities.


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• The system was compared with a reference conventional system.

• The user–centred system was designed with upgraded methodology of engineering design (Asimow 1962; Dovjak, 2012).

System designMethodsIn

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Figure 1.System design.

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• The basis for the design: vital physiological processes in human body that require a dynamic constancy or balance.

• 3 essential components of all homeostatic control mechanisms : detector, integrator and effector.

Methods System designMethodsIn

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Figure 2. Basic elements of homeostatic control mechanism (Bresjanac & Rupnik 1999).

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Al Faisaliah Tower 2,

Riyadh,SaudiaArabia

• It is installed into a test active space, UL FGG; it includes 6radiative panels connected with ICSIE system .

The user–centred system MethodsIn

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Figure 3. Basic architecture of the ICSIE system Indi

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Riyadh,SaudiaArabiaThe user–centred system Methodology

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ings • It enables the control of indoor air temperature,

CO2 and illuminance under the influence of outdoor environment and users` requests.

• The basic elements of the ICSIE system = elements of homeostatic control mechanism: sensor network system (detector), regulation system (integrator) and actuator system (effector).


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(integrator) and actuator system (effector).


Riyadh,SaudiaArabiaUsers’ characteristicsMethodologyIn

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gs • 3 virtual residential users were simulated for the analysis of individual thermal comfort conditions.

• The user– centred system was tested regarding simulation of individual thermal comfort conditions and measured energy use.

• The efficiency of the user–centred system was compared with conventional system (oil-filled electric heaters and split system with indoor A/C unit).

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electric heaters and split system with indoor A/C unit).

User/activityMetabolic rate

[met]Effective clothing

insulation [clo]Grandfather,watching TV

1.0 0.7

Teenager, weight-training

6.0 0.2

Mother, Yoga 1.2 0.7

Table 1. Users’ characteristics and specific activities

Methodology

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• In the simulation users were exposed to experimental conditions based on in–situ real–time measurements .

• In the case of conventional system Tai =Tmr = To; in the case of user–centred system Tai ≠Tmr ≠ To differed.

• User–centred system enabled to set up different combinations of Tai and Tmr and To that resulted in optimal human body exergy balance for every individual separately.

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System User T ai [°C] T mr [°C] v [m/s] RH in [%]

ConventionalAll 21 21 0.1 40

User–centredGrandfather

Teenager

Mother

22

17

22

24

19

24

0.1

0.1

0.1

4040

40

Table 3. Real-time experimental conditions for the simulation ofindividual thermal comfort conditions


Riyadh,SaudiaArabiaHuman body exergy calculationsMethods

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ings • For the analysis of individual thermal comfort conditions,

exergy concept was introduced. • Exergy analysis jointly treats processes inside the

human body and processes in built environment .• Human body exergy balance model developed by

Shukuya et al. (2010), upgraded into spreadsheet software for the calculation of hbEXCr (Iwamatsu and

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software for the calculation of hbEXCr (Iwamatsu and Asada, 2009).

Warm rad.

Breath air Exgconsumption

Exhalation,sweat

from innerpart

Cool/warm rad.

Cool/warm conv. Warm conv.

[ ] [ ]nconsumptioExergyinputExergy − [ ] [ ]outputExergystoredExergy +=


Riyadh,SaudiaArabiaHuman body exergy calculationsMethods

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ings • To maintain comfort conditions , it is important that

the exergy consumption and stored exergy are at optimal values with a rational combination of exergy input and output.

• Individual thermal comfort conditions were analysed by human body exergy balance , calculated human


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by human body exergy balance , calculated human body exergy consumption rates and PMV index with spread sheet software developed by Hideo Asada (Shukuya et al. 2010).

• For exergy calculations, the reference environmental temperature (the outdoor environmental temperature, Tao) and RHout = Tai and RHin.


Riyadh,SaudiaArabiaResults

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Conventional system

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Figure 4. Human body exergy balances for three virtual users of active space equipped with conventional system.


Riyadh,SaudiaArabiaUser-centred system Results

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Figure 5. Human body exergy balances for three virtualusers of active space equipped with user–centredsystem.


Riyadh,SaudiaArabia

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Table 4. Results of energy use (Ccool, Cheat) for selected conditions.

• Approximately the same conditions were selected for the systems’ comparison (equal set-point T, time period, Tao and Tai variate among systems ±0.5 K; 0.8% assumed error).

• The measured energy use for space heating was by 11% lower when using user–centred system compared to th e conventional system. The energy use for space cooli ng was by 73% lower for user–centred system .

User-centred system Results

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System T range[°C]

User–centred Conventional Reduction [%]

Heatingwinter

23–24 Tai=23.3 °CTao= -2.60°C

Cheat=

2.630 MJ

Tai = 23.7°CTao = -2.60°C

Cheat =

2.950 MJ

11

Cooling summer

24–25 Tai=24.83°CTao=19.45°CCcool =1.116 MJ

Tai = 24.30°CTao = 19.88 °C

Ccool =4.068 MJ

73

Table 4. Results of energy use (Ccool, Cheat) for selected conditions.

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Conclusions In

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conditions for various users and activities . These would result in an optimal human body exergy balance .

• To maintain thermal comfort for all users and activities, it is important that exergy consumption and stored exergy are at optimal values with rational combination of exergy inputs and outputs.

• The presented analysis was carried out for three selected


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• The presented analysis was carried out for three selected subjects with different demands and needs for thermal comfort. However, user–centred system is a flexible system .

• It is possible to create optimal microclimatic conditions for every individual user and activities.

• The system could be applied in residential or public buildings.

Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia

ACKNOWLEDGMENTS

Research program Building Construction and Building Physics, UL FGG founded by the Ministry of Higher Education, Science and Technology, Republic of Slovenia, Education, Science and Technology, Republic of Slovenia, COST action C24 Analysis and design of innovative systems with LowEx for application in build environment, CosteXergy,TIGR Sustainable And Innovative Construction P13.1.1.2.03.0003, 3211-10-000465.

individualised climate in future buildings. fact or...

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