Recent air-conditioning systems aim to provide thermal comfort for an unspecified number of residents. However, office workers may perceive the feeling of comfort differently depending on their clothing, metabolic rate, and personal activity level. This may cause difficulties in maintaining an optimal thermal environment. To address this problem, personal air-conditioning has attracted attention, which is highly versatile and can reduce thermal discomfort and provide comfort to all office workers by enabling individual thermal control. Therefore, the authors focused on developing an office chair, the “Cool Chair”, as a chair-type personal air-conditioning system with a cooling function from 2003 to 2016. The authors then added a warming function for year-round operation, creating the “Cool Chair with Warming Function” in 2017. Subjective evaluation results are reported. These experiments using the new chair indicated that the warming function achieves steady state in 30 minutes and the equivalent temperature of the entire body increases by +2°C. In subject experiments, the warming and cooling functions were adjusted according to individual preferences, and the cooling function was used even during winter by some individuals. The authors also confirmed that the feeling of comfort by the subjects improved at both 19°C and 22°C.

In this study, an initial survey of clothing insulation and changes in the metabolic rate of individuals in office spaces was performed to establish the distribution of room temperatures at which individuals perceived a neutral thermal sensation. Subsequently, the indoor thermal environment in four offices was surveyed during the summer with different air-conditioning systems to determine the thermal environment stability in each case. The results revealed that for the required temperature, there was a noticeable difference between the average and most frequent values. Moreover, it was determined that the required temperature distribution is not normal, but rather, it is skewed to the low-temperature side. In addition, the radiant air-conditioning system was found to generate a narrow distribution of the equivalent temperature and hence, facilitated a more uniform thermal environment compared to a convective (multi-unit) air-conditioning system. Therefore, in buildings with convective air-conditioning systems, even if the planar average thermal environment is categorized as comfortable, it may be possible that workers who are sensitive to the cold or heat will complain of discomfort more frequently than those in buildings with radiant air-conditioning systems because the probability of workers sitting in cold- or hot-spot areas is higher in the former case.

This study aims to assess the thermal conditions of an indoor environment deemed unacceptable by workers. For this purpose, Ostracon, a voting device, was developed to record the physical environment at the time a worker presses a button to express a complaint. Ostracon was used to record the opinions of 90 workers about their thermal environment in six offices during the summer. The results show that workers found the indoor thermal environment unacceptable even when the static thermal conditions were within a range that was predicted to be comfortable. Moreover, most of the workers' complaints were expressed moments after returning from tasks performed outside the office. This suggests that the workers' complaints were influenced by factors other than the indoor environment such as thermal history.

In an office space, each office worker has his or her own preference for thermal environmental conditions and personal thermal comfort. Recently, as a solution to such problems, personal air-conditioning systems have attracted much attention to improve the thermal comfort of office workers. Using a personal air-conditioning system, each worker can adjust the thermal environment to his or her desired preference. To create a personal air-conditioning system, the authors enhance an office chair using an airflow generator that has an environment adjustment function. This chair, called a “cool chair,” has been under development since 2003. In this study, the authors develop a new model called cool chair 2016 where thermal environmental selection range is improved. In a physical performance test using a thermal manikin, the equivalent temperature of the entire body was noticeably lower than that of a user seated in a normal office chair. Moreover, the results of a trial test by workers in an office show that workers who used the cool chair felt more comfortable.

Variable refrigerant flow (VRF) systems are used as air conditioning systems in small and medium-sized buildings in Japan. Conventionally, the two most popular types of VRF systems are the Electrical Motor-Driven VRF system (EHP) and the Gas Engine Driven VRF system (GHP). However, in recent years, society has been increasingly demanding energy saving and the best energy mix. This required an air conditioning system that is capable of flexibly using energy according to the application and situation. Consequently, a hybrid air conditioning system (called the Integrated Hybrid VRF system) that satisfies this need was developed. The developed system enables operation in accordance with energy prices and usage situations by connecting a GHP and an EHP in a single refrigerant cycle. Subsequently, in recent years, the Integrated Hybrid VRF system has been utilized in small and medium-sized buildings. However, the actual performance characteristics of this system have not yet been investigated. In this study, measurements were obtained during the actual operation of an Integrated Hybrid VRF system operating in an office building and controlled by a remote monitoring server to enable optimal operation according to the application and situation. In this report, the actual operational status of the Integrated Hybrid VRF system with optimal operational control is presented.

This study was conducted to characterise thermal environmental acceptability for various air-conditioning systems. The authors developed a new thermal comfort index called a P-R chart using the concepts of "provided temperature" and "required temperature" for use in evaluating uniform, high-quality indoor thermal environments and non-uniform, unsteady thermal environments. In this study, first, the authors surveyed the required temperature distribution of workers. Then they surveyed indoor thermal environmental stabilities in the four offices during the summer with different air-conditioning systems to calculate provided temperature distribution. Finally, the indoor thermal acceptability in offices was evaluated using the P-R chart. The results showed that the convective air-conditioning systems caused wide temporal and spatial variations in the thermal environment. Therefore, in buildings with convective air-conditioning systems, even if the planar average thermal environment is categorised as comfortable, it is presumed that workers sensitive to cold or heat will complain of discomfort more frequently than those in buildings with radiant air-conditioning systems and floor-supply displacement HVAC systems, because the probability of workers sitting in cold- or hot-spot areas is higher in the former case.

The authors investigated an office building in Japan incorporating energy-saving features and environmental technology. The building is medium-sized and incorporates two air-conditioning systems: a natural ventilation system and radiation air-conditioning system. The temperature environment of the building and its psychological effects on office workers were surveyed using a questionnaire. The measurements of the natural ventilation system were made in 2016. The natural ventilation system of this building reduces the indoor temperature by first opening the window. The ceiling uses the heat storage capacity of concrete to retain a low temperature in the room during the night. Air flows through the room with the natural ventilation system. Further, various problems occur because of noise, and the building has a constantly fluctuating environment. However, according to the results, even in such a natural ventilation system in which the indoor environment changes, office workers are able to conduct business without much dissatisfaction.

Few case studies have examined the actual operation of variable refrigerant flow systems. The installation conditions for each case, such as the number of indoor units connected, piping length, height difference, and refrigerant filling budget, are not fixed. Therefore, accurately grasping the changes in performance is difficult. Moreover, specifying the performance evaluation method is necessary because of the complex and diverse operating conditions for each case. The system performance intended by the air conditioning designer/builder is not attained because the actual driving situation differs for each property. Therefore, possible complaints of the system being “too hot” or “too cold” raise a concern.

This work clarified the effectiveness and comfort of an air-conditioning system with variable airflow by measurement and questionnaire survey. This air-conditioning system can create horizontal and vertical airflows by a special air outlet. In addition, this system can adjust air volume. Thus, with this system, one can make choices in line with one's airflow preferences, within different air-conditioning zones. Airflow can be set using a five-stage mode, through a user interface that is installed in the room. The measurement results confirmed that air speed difference was attached to each thermal sensation setting, and air volume adjustment functioned effectively. The questionnaire results confirmed that over 90% of officer workers are somewhat comfortable and that the air-conditioning system is extremely comfortable.

Radiant air-conditioning systems and floor-supply displacement heating, ventilation, and air conditioning (HVAC) systems have recently attracted considerable attention. However, such systems have not yet seen widespread use because the degree to which they increase thermal comfort is not clear. In this study, the authors measured the planar thermal deviation during summer in four offices: two offices employed a radiant air-conditioning system and a floor-supply displacement HVAC system, and the other two offices employed convective air-conditioning systems. The results showed that the convective air-conditioning system caused wide temporal and spatial variations in the thermal environment. Therefore, in buildings with convective air-conditioning systems, even if the planar average thermal environment was categorized as comfortable, it was presumed that workers who were sensitive to cold or heat complained of discomfort more often than those in buildings with radiant air-conditioning systems because the probability of workers sitting in cold or hot spots increased.

<p>研究対象施設にはマイクロコジェネレーションシステムを用いた冷温水供給系統と空気熱源ヒートポンプによる冷温水供給系統がある。両系統の同時起動が不要な低負荷時に、いずれの系統を優先的に起動すべきかは、外界条件や電力およびガス料金などに依存する。本報では簡単なエネルギーフローモデルを作成し、マイクロコジェネレーションシステムと空気熱源ヒートポンプの起動判定を行う方法を示す。</p>

<p>S社本社における執務者の快適性の把握を目的とし,2012年,2013年に実施された夏期アンケート調査,本年度夏期に実施されたオストラコンによる受容度申告調査について報告する。結果として2013年のアンケート調査にあたり,室内設定温湿度が2012年の調査時から変更があったため各項目における回答の変化が認められた。オストラコン調査では温冷感申告,受容申告は快適範囲内外に見られたが,受容申告「受け入れられる」の申告は快適範囲外における申告割合の方が多い結果となった。</p>

This study aims to establish a new thermal comfort index for evaluating air-conditioning systems, and introduces a new thermal comfort index for the provided and required temperatures. The authors performed comparison verification experiments on the temperature distribution of radiant air-conditioning and convective air-conditioning systems. The results showed the temperature provided by the convective air-conditioning system to have a wide distribution, unlike that of the radiant air-conditioning system. Based on these results, the authors propose a probabilistic thermal acceptability evaluation using the concepts of "provided temperature" and "required temperature". The authors consider this evaluation method to be applicable for non-steady thermal environments as well as uniform high quality indoor thermal environments using radiant air-conditioning systems, and personalized air-conditioning systems.