Joint FP5 ENERGIE Info-day and EnerBuild RTD Project Meeting JAPANESE BUILDING ENER

GY RESEACH7 September 2001, Malmo

Ken-ichi KimuraProfessor, Advanced Research Institute fo

r Science and Engineering,

Waseda University, Tokyo

Fax:+81-3-3209-8316

E-mail: kkimura@mn.waseda.ac.jp

Climate of Japan

• Japanese archipelago ranges from cold to subtropical regions.

• In central mild areas, heating season: November-April in residential buildings January-March in office buildings.

Energy Use Trends in JapanIndustrial Sector Residential and

Commercial SectorTransportation Sector

0

2000

4000

6000

8000

10000

12000

14000

16000

73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98

[PJ]

- S. Ando

Residential Energy Breakdowns by District

1/3 of CO2 are related to buildings in Japan

Operation Energy of an Office Building

Energy Conservation and

Natural Energy Utilisationare different.

Definition of Energy Conservation

• Minimisation of Energy Use while maintaining desire of people.

• Energy may be used as much as they want unless they think it wasteful.

• Energy conservation is not enough to meet the target of Kyoto protocol.

Natural Energy Utilisation

• Solar thermal• Photovoltaics• Wind power• Geothermal power• Ambient energy

Solar Hot Water Heaters

• Solar water heaters are installed in about 1/10 of total households.

• Forced circulation type of domestic solar water heating system can be seen in houses.

Solar Hot Water System

• Swimming pools

• Elderly　people’s homes

• Hospitals

• Schools

• Apartments

Passive Solar Space Heating

• Traditionally common in residences.

• Insulation and air-tightness are prerequisites for passive solar heating

Passive Cooling in Residences

• Natural ventilation and sun shading are pre-requisites.

• Nocturnal ventilation• Cool tube• Earth contact floor• Roof garden for

evaporative cooling• Nocturnal radiation

Improvement in Efficiency of Household Appliances

• Refrigerators• Lighting bulbs

(Compact lamps are not common in Japan.)

• Room Air-Conditioners

Colour TV

Air Conditioner

Refrigerator

Year

Energy Conservation in Buildings

• Energy Conscious Designs

• Energy Reduction in Lighting

• Energy Reduction in HVAC

• Energy Reduction in Office Machines

Energy Conservation in HVAC

• Heat Recovery System

• Variable Air/Water Volume System

• Free Cooling/ Night Purge

• Sun Shading

• Air Flow Windows

• Controls for Efficient Operation

• Set Point Temperature and Humidity

Thermal Comfort and Energy Conservation

• 1 degree of change in set point temperature makes 10% of energy saving in both heating and cooling.

• Slight increase in air movement substantially reduces cooling load.

Indoor Air Quality and Energy Conservation

• Displacement ventilation

• Occupied zone air conditioning

• Minimum allowable rate of ventilation

Occupied Zone Air Conditioning in Large Spaces

0

500

1000

1500

Hea

t L

oad

[W

/㎡・

day]

MeasurementOccupied zone Air-ConditionOverall Air-Conditioning

8/18 8/208/19 8/23 8/24 2/16 2/18 2/19 2/21 2/22

Direct Sunlight Introduction

Photovoltaics Integration in Architecture

Residential PhotovoltaicSystem Installation

NumberCapacity

[MW]

PowerGeneration

[106kWh]

PowerRequired

[106kWh]

PVContribution

[%]

60,000 219 230 897,600 0.026

1,370,000 5,000 5,256 1,056,000 0.500

Residential Photovolaic Cost

2000 Aug. 2002 Forcast

PV module cost 56.0 (63%) 41.4 (64%)Ancilary equipment cost 20.9 (24%) 12.2 (19%)Installation cost 11.9 (13%) 11.2 (17%)Total system cost 88.8(100%) 64.8(100%)

PV Panels Backed with Air Collector

Kyocera House

Natural Energy Utilisation in Vernacular Architecture

Massive House in Kawagoe

Modern Use of Vernacular Technologies

Earth Covered Building

Solar Architecture

• Heavy insulation and air-tightness

• natural ventilation and sun shading

• passive solar heating

• solar domestic hot water system

• PV for appliances

IEA Task 13 AdvancedJapanese House-WISH House

Kimura Solar House - 1972

• Movable collector panels

• Semi-basement with greenhouse

• Floor heating by heat pump

• Solar domestic hot water

• PV roof (2001)

Sagara Solar House - 1979

• Hybrid solar• Outside

insulation• No auxiliary for

space heating• 5028 kWh/a for

total household

TEPCO Solar House - 1988• Earth contact floor• Rock bed storage coupled

with air collector and heat pump

• Sun space• Heat pump for hot water

from space cooling with off-peak electricity

• Phase change material floor• 7800kWh/a for total

household

Solar Chimney and PV Panels

• School building of Kitakyushu University, Faculty of Environmental Engineering

Carbon Emission from Buildings by Structural Types

-100

-50

0

50

100

150

200

WOODEN STEELREINFORCEDCONCRETE

REINFORCEDCONCRETE

STEEL AVERAGE

CA

RB

ON

EM

ISS

ION

PR

OM

BU

ILD

ING

SF

OR

FLO

OR

AR

EA

[ｋｇ

/m2]

WOOD(-)

OTHER MATERIALS

TRANSPORTATION

STEEL

CERAMICS

CONCRETE

WOOD(+)

Global Environment Committee,AIJ 1992

Conclusion-1

• Energy 　 conservation has a largest potential in reducing energy requirements in building sector.

• Different types of natural energy utilisation must be sought for different conditions.

Conclusion-2

• A slight discomfort must be accepted for reducing energy use and warming gas emission.

• It can be regarded possible to meet the target level of Kyoto protocol as far as building sector is concerned in Japan.