Individualised climate in future buildings. Fact or fiction?

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1 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 Individualised climate in future buildings. Fact or fiction? Mateja Dovjak *,Masanori Shukuya, Aleš Krainer * Corresponding mdovjak@fgg.uni-lj.si Vienna, 9-11 September 2013

2 Problem te in future buildings Individualised clima Users Specific activities Environmental factors Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

3 Individualised climate in future buildings Problem 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 $ per m2 (Peyton 1999). Even a small improvement in productivity and reduction in absenteeism are more worthy than any energy savings. Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

4 Individualised climat te in future buildings Purpose 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. The system was compared with a reference conventional system. Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

5 Individualised climat te in future buildings Methods System design The user centred system was designed with upgraded methodology of engineering design (Asimow 1962; Dovjak, 2012). Figure 1. System design.

6 Individualised climat te in future buildings Methods System design 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. Figure 2. Basic elements of homeostatic control mechanism (Bresjanac & Rupnik 1999).

7 Methods The user centred system Al Faisaliah Tower 2, Riyadh,SaudiaArabia Individualised climate in future buildings It is installed into a test active space, UL FGG; it includes 6 radiative panels connected with ICSIE system. Figure 3. Basic architecture of the ICSIE system

8 Individualised clima ate in future buildings Methodology The user centred system Al Faisaliah Tower 2, Riyadh,SaudiaArabia It enables the control of indoor air temperature, CO 2 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). Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

9 Individualised clima ate in future buildings Methodology Users characteristics Al Faisaliah Tower 2, Riyadh,SaudiaArabia 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). Table 1. Users characteristics and specific activities User/activity Metabolic rate [met] Effective clothing insulation [clo] Grandfather, watching TV Teenager, weighttraining Mother, Yoga

10 Individualised climate in future buildings Methodology In the simulation users were exposed to experimental conditions based on in situ real time measurements. In the case of conventional system T ai =T mr = T o ; in the case of user centred system T ai T mr T o differed. User centred system enabled to set up different combinations of T ai and T mr and T o that resulted in optimal human body exergy balance for every individual separately. Table 3. Real-time experimental conditions for the simulation of individual thermal comfort conditions System User T ai [ C] T mr [ C] v [m/s] RH in [%] Conventional User centred All Grandfather Teenager Mother

11 Individualised climat te in future buildings Methods Al Faisaliah Tower 2, Human body exergy calculations Riyadh,SaudiaArabia 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 Asada, 2009). [ Exergy input] [ Exergy consumption ] = [ Exergy stored ] + [ Exergy output ] Cool/warm rad. Breath air Cool/warm conv. Exg consumption from inner part Exhalation, sweat Warm rad. Warm conv.

12 Individualised climat te in future buildings Methods Al Faisaliah Tower 2, Human body exergy calculations Riyadh,SaudiaArabia 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 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. Chair for Buildings and Constructional Complexes, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia

13 Individualised climat te in future buildings Results Conventional system Al Faisaliah Tower 2, Riyadh,SaudiaArabia Figure 4. Human body exergy balances for three virtual users of active space equipped with conventional system.

14 te in future buildings Individualised climat Results User-centred system Al Faisaliah Tower 2, Riyadh,SaudiaArabia Figure 5. Human body exergy balances for three virtual users of active space equipped with user centred system.

15 Individualised climate te in in future buildings Results User-centred system Al Faisaliah Tower 2, Riyadh,SaudiaArabia 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 the conventional system. The energy use for space cooling was by 73% lower for user centred system. Table 4. Results of energy use (C cool, C heat ) for selected conditions. System Heating winter Cooling summer T range [ C] T ai =23.3 C User centred Conventional Reduction [%] T ao = C C heat = cool MJ T ai =24.83 C T ao =19.45 C C cool = MJ heat T ai = 23.7 C T ao = C C heat = MJ T ai = C T ao = C C cool = MJ 11 73

16 Conclusions te in future buildings Individualised clima The main role of user centred system is to create optimal 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 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, Slovenia

17 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, COST action C24 Analysis and design of innovative systems with LowEx for application in build environment, CosteXergy, TIGR Sustainable And Innovative Construction P ,