Thermal comfort and Energy Efficiency in

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1 Faculty of Engineering Division of Infrastructure, Geomatics and Architecture Architecture, Climate & Environment Research Group INVITED LECTURE BY DR MAUREEN TREBILCOCK Thermal comfort and Energy Efficiency in School Buildings Wednesday 9 th April 2014 Thermal comfort and Energy Efficiency in School Buildings Invited Lecture by Dr Maureen Trebilcock Dr Maureen Trebilcock is an University of Nottingham alumnus and Head of the Master Course in Sustainable Habitat and Energy Efficiency, Universidad del Bio-Bio, Chile. The talk described the findings of Dr Trebilcock s work at schools located at the north, centre and south of Chile, under different climatic conditions. The first part will review current thermal comfort parameters based on a field study, while the second and third part will show how different design strategies can have an impact on predicted energy demand and daylighting conditions, based on parametric analysis and simulation. Architecture, Climate and Environment Research Group Division of Infrastructure, Geomatics and Architecture 1

2 Thermal comfort and Energy Efficiency in School Buildings Maureen Trebilcock, Universidad del Bío-Bío Concepción, Chile STRUCTURE 1. Field study of thermal comfort in school buildings in Chile 2. Parametric analysis of classrooms typologies 3. Design proposals for an Integral Classroom 2

3 Children spend 6 hours per day at School for 12 years School buildings with good environmental performance can considerably improve the attention capacity, concentration, learning, hearing and behaviour of the students if the students feel uncomfortable or distracted by noise, by poor lighting conditions, due to the lack of heating, cooling and/or ventilation, their capacity to learn will be affected SCHOOL BUILDINGS IN CHILE No regulations for energy efficiency and very limited regulations for environmental comfort. Most schools are passive (neither heating nor cooling system) with low building quality. Previous research has found that environmental conditions in school classrooms are very poor, particularly in terms of air quality and thermal comfort 3

4 1. FIELD STUDY OF THERMAL COMFORT Field study on thermal comfort in school buildings located at different climatic conditions, looking at how climatic and socioeconomic aspects influence thermal sensation of students. IQUIQUE SANTIAGO 2 schools with high vulnerability (poverty) PUERTO MONTT 2 schools with low vulnerability (poverty) FIELD STUDY OF THERMAL COMFORT questionnaires measurements 4

5 Thermal sensation vote Thermal sensation vote Temperature C FIELD STUDY OF THERMAL COMFORT Results of four schools in Santiago all passive buildings, no heating / cooling T ext T int Membrillar T int India T int JP Duarte T int Siria Air temperature in winter Air temperature in summer Indoor temperature fluctuates with external temperature, and they are generally low in winter and high in summer FIELD STUDY OF THERMAL COMFORT Thermal sensation vote / Dry bulb temperature Dry bulb temperature Winter y = x R² = Thermal sensation vote / Dry bulb temperature Dry bulb temperature Summer y = x R² = Neutral temperature Number of Neutral temperature Number of winter ( C) votes winter summer ( C) votes summer All cases Neutral temperature in winter based on 1189 votes from 4 schools is 16,7 C, but it varies form 15,5 C for both schools with high vulnerability to 17,4 C for both schools with low vulnerability, suggesting that there is a relation between thermal sensation and vulnerability (poverty). 5

6 2. PARAMETRIC ANALYSIS OF CLASSROOM TYPOLOGIES The aim of the study was to determine how different design parameters influence the total energy demand of a school classroom in different climatic zones of the country. METHODOLOGY Dynamic simulation of a basic classroom typology located in 10 Chilean cities, representing different climatic zones. Climates vary from mild climatic conditions on the northern coast to very harsh conditions in the extreme south, passing through zones with hot summers and relatively cold winters in the central area. basic classroom typology 6

7 METHODOLOGY Design parameter Orientation main façade Variables north, south, east, west Glazing area/ floor area (%) basic classroom typology Type of glazing Single, double, double low-e, double solar control Infiltration rate (ach) 0,5 1,5 2,5 Thermal envelope A-B-C-D-E-F-G-H-I-K SIMULATION PROCESS combinations per city Dynamic simulation with Energy Plus Parametric analysis with Gen Opt To determine energy demand for Heating Cooling Lighting (as a result of daylighting contribution) Temperature set-point : 20 C for heating and 26 C for cooling, Lighting requirement : 300 lux at the work-plane 7

8 AVERAGE ENERGY DEMAND FOR EACH CITY kwh/m 2 y mostly cooling (overheating) mostly heating INFLUENCE OF DESIGN PARAMETERS Difference in energy demand (kwh/m 2 y) The most important design parameter is the infiltration rate, particularly in the southern (and coldest) zones. Another influential design parameter is orientation, which has a higher impact on the southern zones, as well as the thermal envelope. 8

9 RESULTS BY CLIMATIC ZONES kwh/m 2 y Punta Arenas (south extreme) Iquique (north litoral) Santiago (central interior) RESULTS BY CLIMATIC ZONES: Iquique (northern coastal zone) The results for Iquique show an important variation in energy demand between the best and worst cases, which rely mostly on the cooling demand. worst cases best cases 9

10 RESULTS BY CLIMATIC ZONES: Iquique (northern coastal zone) Best design variables for each orientation RESULTS BY CLIMATIC ZONES: Santiago (central interior zone) worst cases best cases Smaller variation between the performance of the best and worst cases than in Iquique and Punta Arenas, due to the fact that this climate varies significantly between summer and winter, which means that some features and appropriate for winter conditions and others are appropriate for summer conditions. 10

11 RESULTS BY CLIMATIC ZONES: Punta Arenas (extreme south zone) worst cases best cases The results for Punta Arenas show an important variation in energy demand between the best and worst cases, which rely mostly on the heating demand, as there is no cooling demand.. 3. Design Proposals for an Integral Classroom Integral classroom 1 Architect School Designer Acustic Ing. Integral classroom 2 Integral classroom Energy efficiency & Passive Design Thermal comfort Mechanical Ing. (ventilation) Ilumination Integral classroom 3 Integral classroom 4 11

12 Iquique NORTH Santiago CENTRE SOUTH Punta Arenas Evaluating performance Thermal Demand Lighting Acoustic analysis Heating Cooling ConsideringUnderground heat exchanger (north and centre) or Heat recovery system (south) Daylight Factor Average Illuminance Surface in range Daylighting Uniformity Daylighting Autonomy Energy Demand. Intelligibility of the voice Acoustic insulation from aerial noise: Facade Between classrooms Upper floor EnergyPlus ZoneEarthTube CalcSoilSurfTemp DesignBuilder, HVAC Radiance Matlab SONarchitect ISO INSUL EASE ZORBA 12

13 NORTHERN ZONE IQUIQUE : Littoral North South, West BWn: arid with abundant cloudiness 1 TURBID SKY North classroom North facing classroom 2 TURBID SKY East facing classroom 13

14 CENTRAL ZONE l SANTIAGO : Inland centre: South, West Csb: warm temperate with winter rainfall 1 North facing classroom 2 East facing classroom 14

15 SOUTHERN ZONE PUNTA ARENAS : Extreme South 53 8 South, West BSk s: very cold semiarid with winter rains 1 North facing classroom 2 East facing classroom 15

16 Other proposals Other proposals 16

17 NEW SCHOOL BUILDINGS Instituto Superior de Comercio N 2 Joaquín Vera Morales (INSUCO) R. Strappa, J.E. Barros, D. García de la Huerta, A. Echeverría, M. Wood arqtos. + ArqEnergía consultores ACHEE NEW SCHOOL BUILDINGS Liceo Artístico Experimental Santiago Martín Hurtado arqtos. + IDIEM consultores ACHEE 17

18 NEW SCHOOL BUILDINGS Liceo Comercial de San Bernardo Cruz & Browne arqtos. + IDIEM consultores ACHEE NEW SCHOOL BUILDINGS Liceo Politécnico de Curacautín Crisosto Arqtos. + ArqEnergía consultores ACHEE 18

19 NEW SCHOOL BUILDINGS Liceo Industrial de Nueva Imperial Marsino y Santander Arquitectos + Araucanía Consultores Conclusions The field work shows that indoor thermal conditions in school classrooms are very poor, with low temperature in winter and hogh temperature in summer. Neutral comfort vote is lower than literature, with differences according to vulnerability and poverty of children. With the aim of improving environmental conditions, parametric analysis of classrooms typologies allowed to look at multiple design variables at the same time, with three different energy outputs: heating, cooling and lighting. Detailed simulation of design proposals for each climatic zone allowed to look at more detailed design features, concluding that it is possible to achieve good energy and environmental performance with passive design strategies. Integral classroo m 19