Koki Kikuta

ANALYSIS ON HEATING LOAD IN HOUSING IN COLD CLIMATE AREA BY USING GIS DATA: Influence of buildings around a site on direct solar gain@@@ダイレクトソーラーゲイン効果に作用する周辺建物の影響の把握

Direct solar heat gain (hereafter DSHG) is expected to decrease heating energy consumption of housings with airtightness and thick insulation in northern region. It is important to calculate precise solar heat gain through window since the values influence on the strategy whether we should use DSHG or not. In this report we suggest the method to calculate solar radiation in a site where build a building. Then the relationship between thermal environment and heating energy is analyzed by using the climate data combined with GIS data. The results identify that southern sky factor is able to explain an effect of DSHG.

Analysis of cooling characteristics in datacenter using outdoor air cooling

Advancements in information technology have proceeded with developments in information and communication technology (ICT), increasing the demand for building datacenters. The datacenter we studied is located in Ishikari, a cold region in Hokkaido, Japan. The data center cools its electrical devices by outdoor air. We argue that this cooling system is more efficient than other more conventional systems. This paper comprises five sections. In Section 1, we present the background for our work and our objectives. In Section 2, we give an overview of the Ishikari datacenter and discuss the temperature characteristics obtained from annual measurements. We then discuss two problems, short circuit (cool air is exhausted from the server room without passing through the server racks) and recirculation(hot air exhausted from electronic devices goes back through an non-operational part in a rack to the cool area in a server room). In Section 3, we assess the observation results given in Section 2 by using indicators we introduce. The room exhaust-heat efficiency was 0.71 in room A and 0.67 in room B. This means that about 30% of cooling air did not pass through the devices. The equipment reabsorption ratio was 0.30 in room A. In section 4, we discuss our estimation of the annual power consumption for the ventilation flow ratio by using four different patterns. The patterns differed depending on the air conditioning supply-air temperature; 18°C or 27°C, and whether a cap on the operational part in server racks was set. We found that the best method of controlling the cooling system was an air conditioning supply-air temperature of 27° C, set cap, and ventilation flow ratio of 0.51. With this method, the annual power usage effectiveness of this data center was estimated to be 1.11 in room A. In Section 5, we summarize the results of our research.

Estimation of the solar radiation load at every floor in skylighted void space

Recently, buildings that adopted the external insulation method that is possible to take the thick insulation are widely prevalent in cold regions. While the reduction of heating load in winter is generally expected, the increase of cooling load in summer is concerned. So, it is necessary to devise the buildings and facilities like natural ventilation and solar control. The aim of this paper is to estimate the solar radiation load at every floor caused by incident light in skylighted void space. Therefore, we calculate the solar irradiance using ideas of luminous efficacy about the illuminance from the illumination distribution to every floor, and show details of solar radiation load at every floor by model experiment and numerical analysis.