Corporación de Desarrollo Tecnológico Sexta conferencia tecnológica

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Corporación de Desarrollo

Tecnológico

Sexta conferencia tecnológica

Baruch Givoni

www.cdt.cl

09 julio 2003

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Building Design Climatic Objectives :

Lowering indoor daytime temperatures in summer, in hot

places, below outdoor temperatures.

Providing effective natural ventilation when it improves

comfort.

Providing comfortable indoor night temperatures, in hot

places.

In Winter: using solar radiation for heating.

Prevention of condensation in winter.

Baruch Givoni

Baruch Givoni Presentación CDT 8/7/2003 Presentación CDT 8/7/2003 Fundación ChileFundación Chile

Maximums at Different Cities

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January March May July September November

°C

Arica

Antofagas

Calama

La Serena

Ovalle

Valparais

Santiago

Concepci

Temuco

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Minimum at Different Cities

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January March May July September November

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Arica

Antofagasta

Calama

La Serena

Ovalle

Valparaiso

Santiago

Concepción

Temuco

Punta

Arenas

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Design Factors Affecting Indoor Temperatures

• Absorbed and Penetrating Solar Energy;

• Ventilation Rates and Diurnal Patterns;

• Heat Generated Within the Building

(mainly concerning winter conditions).

• Properties of Building Materials and Elements;

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Walls’ Orientation and Color – Exterior

Temperatures of White and Gray Walls

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Walls’ Orientation and Color – Indoor

Temperatures of White and Gray Walls

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Windows’ Orientation and Shading

Conditions

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White Walls – Windows Fully Shaded

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Materials’ Thermal Properties

• Thermal Conductivity

• Density

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Conductivity and Density of Materials

Conductivity=0.072exp(1.35(Density/1000))

• With higher density the thermal conductivity of a

material increases progressively.

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Condensation Issues

• Indoor Humidity Levels

• Indoor Surface Temperatures

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Indoor Surface Temperatures in Winter

• In winter, in heated buildings, indoor

surface temperatures of the external walls

and the roof are lower than the indoor air

temperature.

• The actual surface temperatures depend on

the insulation level and the thickness of the

walls.

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Cold Bridges

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Direct Gain Scheme

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White’ House – Santa Fe

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White’ House Operable Insulation

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House with Roof Monitors

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Trombe (Storage) Walls

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B. Hunn House – Los Alamos

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SUN SPACES

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Balcomb’s House

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Interior View

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Heat Transfer from Sun-space to Adjoining

and to Remote Rooms.

Large doors between sunspace and adjoining

rooms

Fans at the top of walls between sunspace and

adjoining rooms

Under-ceiling or over-ceiling ducts with fans

connecting to remote rooms.

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VISIT IN CHINA - 1989

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Student Dorms # 1 in China

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Elementary School In China

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PASSIVE COOLING:

• Night Ventilative Cooling;

• Radiant Cooling;

• Direct Evaporative Cooling;

• Indirect Evaporative Cooling;

• Utilizing Cooled Soil as a Cooling Source

• Under Santiago’s climate and public

building types – the most practical cooling

system is Night Ventilative cooling

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Night Ventilative Cooling

• Buildings are ventilated at night to cool down the

internal thermal mass.

• In places where winds are weak at night –

ventilation has to be assisted by exhaust fan.

• During the day buildings have to be closed, to

minimize heating by the warmer outdoor air.

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Research in Pala, California

• Two buildings: low mass and “high mass”.

• Low mass: insulated wood construction.

• “High Mass”: 10 cm concrete + Insulation,

Roof similar to low mass building.

* Initial External Color: Dark.

Testing different conditions of shading, ventilation

and external color.

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Ventilation - Day and Night

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Low Mass and High Mass Buildings Closed Day and

Night

Shaded & Closed Windows. 29/7-4/8, 1993

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Low-Mass

High-Mass

Average DBT

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Low Mass and High Mass Buildings Cooled

by Night Ventilation

NIGHT VENTED - SEPT. 26 - OCT. 2nd, 1993

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T e m per at u res ( C )

DBT LOW-MASS HIGH-MASS DBT-AVG

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