Paper 2
Estimation of Cooling Energy
Reduction by Utilizing Cross-Ventilation in Detached Houses, within the
Japanese newly introduced Energy Regulation - Evaluating Energy
Consumption for Different Uses
Takao
Sawachi1, Shigeki Nishizawa2, Hiromi Habara1
and Hisashi Miura1
1
Building Research Institute, Japan
2 National Institute for Land and Infrastructure
Management,
Ministry of Land, Infrastructure, Transport and
Tourism, Japan
Abstract
The reduction of carbon dioxide emission due to energy consumption in
the household sector is an urgent task, worldwide. As a measure to respond
to the task, a new regulation has just been enforced since April 2009, in
Japan. This regulation evaluates the energy performance of detached houses
by estimating the primary energy consumption for different uses, namely,
heating, cooling, ventilation, domestic hot water and lighting.
Especially in mild or hot climates, it has been frequently claimed by
practitioners that the regulation, which is heavily focused on insulation
performance, is not enough and broader aspects should be equally
evaluated. The effectiveness of cross ventilation in reducing cooling
energy is one of these aspects. However, there have been difficulties to
overcome in predicting the effectiveness of cross ventilation on cooling
energy reduction. Among such difficulties are the decrease of the
discharge coefficient of openings with inclined airflow, variation of the
wind pressure coefficient depending on surrounding conditions, etc.,
occupants' window opening behaviour and actual energy efficiency of air
conditioners depending on their output and outdoor conditions. By
referring to the results from experiments and observations on cross
ventilation and air conditioners, the authors have proposed a solution for
the Japanese new energy regulation on how to predict cooling energy
consumption, taking the above factors into consideration. Even though
there are still problems to be solved, the solution by the authors, shown
in this paper, can be a guidepost to a more reasonable evaluation of the
energy performance for cooling in buildings, as well as to a more
reasonable design practice for windows and openings on the partition
walls.
Key words: energy performance, Japan, regulations, cooling,
cross ventilation, energy consumption.
References
Miura H, Habara H, Hosoi A and Sawachi T: (2008) "Energy
efficiency of room air conditioner under various outdoor conditions and
operating modes", 9th International IEA Heat Pump Conference (Zürich),
20-22 May 2008.
Habara H, Miura H, Sawachi T, Nishizawa S and Hosoi A: (2008)
"Experiment on the effect of natural ventilation on cooling energy
conservation", 29th AIVC conference (Kyoto), 14-16 October 2008.
Nishizawa S, Sawachi T and Maruta E: (2008) "Evaluation of effect
of the wind pressure fluctuation for cross ventilation in the residential
district", 29th AIVC conference (Kyoto), 14-16 October 2008.
Hosoi A, Sawachi T and Miura H: (2007) "Part load characteristic
of COP of residential air conditioner based on measurement in artificial
climate chamber, heating/cooling COP and energy consumption of residential
air conditioner part 1", Journal of Environmental Engineering,
Architectural Inst. of Japan, No. 622, December.
Sawachi T, Nishizawa S, Habara H and Miura H: (2007) "Estimation
on the effectiveness of the cross ventilation as a passive cooling method
for houses", 28th AIVC Conference (Crete).
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Contents
Editorial
The Third International Workshop on Natural Ventilation, Tokyo, Japan 16th
March 2009
Paper 1
The Applicability of Natural Ventilation
- Technical Editorial
Paper
2
Estimation of Cooling Energy Reduction by Utilizing Cross-Ventilation in
Detached Houses, within the Japanese newly introduced Energy Regulation -
Evaluating Energy Consumption for Different Uses
Paper
3
Domain Decomposition Technique Applied to the Evaluation of
Cross-Ventilation Performance of Opening Positions of a Building
Paper
4
Buoyancy Driven Natural Ventilation through Horizontal Openings
Paper
5
Review of Cross-Ventilation Research Papers - from the Working Group for
Natural Ventilation and Cross-Ventilation of the Architectural Institute
of Japan
Paper
6
The Theory of Thermal Comfort in Naturally Ventilated Indoor Environments
- The Pleasure Principle
Paper
7
A Simulation Study on the Reduction of Cooling Loads in a Detached
House by Cross-Ventilation using the Local Dynamic Similarity Model
Paper
8
Verification of the Effect of Cross-Ventilation on Energy
Conservation by Simulating Occupant Behaviour
Paper
9
The Impact of Several Construction Elements on the Thermal Performance of
Solar Chimneys
Paper
10
Natural Ventilation with Dynamic Façades
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