PR2008

Translucent thermal insulation walls forJapanese houses have been designed to allowsolar radiation and daylight to pass through thewalls into the house (Fig. 1) in order to reducethe amount of energy required for heating andlighting and to create a comfortable lightingenvironment. The walls are made of translucentor transparent materials such as glass andthermal insulation material.The walls have been developed withconsideration given to conditions of variousregional climates and housing lots.

An investigation was performed in a middle-corridor-type elementary school in Tolcyo, Japan, equipped with an air-conditioning system for cooling.Temperatures and C02 concentrations weremeasured in classrooms, corridors and outdoors.Visual inspections were made on opened andclosed conditions of windows, doors andcurtains, and pupil numbers in classroomsduring each lesson hour. Pupils' and teachers'thermal environment evaluations andenvironmental control behaviors were obtainedfrom questionnaires.

The Energy Conservation for Buildings andCommunities Systems (ECBCS) is anImplementing Agreement among 23 countriesof the IEA (International Energy Agency) forenergy research and development in buildingsand communities. The ECBCS has nowcompleted 43 major international projectsresulting in demonstrated and adoptedtechnologies and tools with major impacts onenergy efficiency and environmental impacts inbuildings and communities. The ECBCS hasnow completed its 2008-13 strategic plan.

This paper discusses the possibility of asimple solar hot water pre-heating system fordomestic hot water supply. In Japan, the fossilfuel use for hot water supply amounts to about30% of the total in residential buildings. The useof conventional solar hot water heaters has beendecreased draniatically over the last 30 years,although the extensive use should have beenexpected. They are regarded to be notnecessarily cheap and moreover theirappearance has not been preferred by quite afew building designers.

In recent years, the insulation and air-tightnesslevels of newly constructed houses in Japanhave been improved for purpose of energysaving. However, a reduced design of airpermeability (i.e. a high level of air-tightness)will provide insufficient air through infiltrationresulting in a significant and negative impact ona social problem of sick house syndrome. TheJapanese Building Standard has been revised toreduce the concentration of Formaldehydewhich is considered to be one of the maincauses of sick house syndrome.

Conventional air-conditioning control in a roomassumes perfect diffusion of temperature in theroom, and relies on a temperature sensorinstalled on the wall or ceiling of the room, or inthe return duct. Air-conditioning is controlled sothat the sensor temperature becomes equal tothe sensor-set temperature ("set temperature").In reality, however, since thermal stratificationoccurs in a room, the set temperature is oftennot attained in an occupied zone that should beproperly air-conditioned. This may result inexcessive cooling.

An investigation to understand the actual conditionsof smoking spaces was conducted, and itbecame clear that the introduction of a highlyefficientventilation system is necessary, in additionto the securing of a sufficient ventilationvolume. In addition, case studies using CFD andexperiments were conducted on the effects ofintroducing a highly-efficient ventilation systemto smoking rooms.

A roof is one of the most importantcharacteristics of Thai architecture especiallyin a house, traditionally. Also, the roof is apart of the house that mainly effects energysaving due to heat allowance pass through andrelease from indoor space. The study, basedon model experiments, targets to find out theeffects of roof forms on indoor air temperature.The purpose is to give information for roofform types selection in Thai Houses. Models,lxlxl meter boxes, are used for theexperiments by changing their roof forms forcomparison.

Sales data shows that the use of air-to-air heatpumps in New Zealand houses is rapidlyincreasing. This rapid uptake will lead to newenergy and peak power demands on theelectricity supply system. Recent monitoringwork lias found solid fuel burners provided 56%of home heating energy while only 24% waselectricity. Heat puinps are therefore inainlydisplacing non-electric heating, and this mustultimately require additional electricitygeneration, transmission and distributioninfrastructure. Patterns of use will be critical tothe long-term impact.

The effect of downdraft spoilers is questioned.CFD results are presented for a large atriumequipped with downdraft spoilers ("obstacles")to counteract downdraft from glazed faqades.Simulations are in addition presented for oneandtwo-story test rooms, where aspects of theefficiency of downdraft spoilers are investigated.Among conclusions are that the spatial thermalbalance of rooms, e.g. stratification or otherbuoyancy driven flows, are essential to thedowndraft, more so, than downdraft spoilers.