In this study, the indoor air quality and thermal environment of a university facility were analyzed when an air conditioner was operated and natural ventilation was provided; the most effective ...natural ventilation method was also evaluated. The research conditions were established by adjusting the temperature of the air conditioner, and frequency of window openings every hour. The area around the windows that is open for natural ventilation was easily affected by outdoor air temperature and humidity. However, since the air conditioner was operating, there was only a brief period during which the environment was uncomfortable. Therefore, the participants in the questionnaire survey expressed neutrality or slight satisfaction for the thermal environment of the entire space. Setting the room temperature to 25 °C in summer was highly comfortable and generated a satisfactory indoor thermal environment. When the room temperature was set to 20 °C in winter, the thermal comfort level was higher than in the other conditions. Providing natural ventilation for 5 min every 30 min was determined to be effective in maintaining an indoor CO2 concentration of 1000 ppm or less. Facilitating natural ventilation for 10 min every 60 min allowed the entry of a large amount of fresh air; however, due to the extended period in which the windows and doors were closed, there were instances when the indoor CO2 concentration exceeded 1000 ppm. Therefore, providing frequent natural ventilation with short time intervals is effective for improving indoor air quality.
Following the Paris Agreement in 2015, the worldwide focus on global warming countermeasures has intensified. The Japanese government has declared its aim at achieving carbon neutrality by 2050. The ...concept of zero-energy buildings (ZEBs) is based on measures to reduce energy consumption in buildings, the prospects of which are gradually increasing. This study investigated the annual primary energy consumption; as well as evaluated, renewed, and renovated buildings that had a solar power generation system, and utilized solar and geothermal heat. It further examines the prospects of hydrogen production from on-site surplus electricity and the use of hydrogen fuel cells. A considerable difference was observed between the actual energy consumption (213 MJ/m2), and the energy consumption estimated using an energy simulation program (386 MJ/m2). Considerable savings of energy were achieved when evaluated based on the actual annual primary energy consumption of a building. The building attained a near net zero-energy consumption considering the power generated from the photovoltaic system. The study showed potential energy savings in the building by producing hydrogen, using surplus electricity from on-site power generation, and introducing hydrogen fuel cells. It is projected that a building’s energy consumption will be lowered by employing the electricity generated by the hydrogen fuel cell for standby power, water heating, and regenerating heat from the desiccant system.
This study measured ventilation volumes and particle concentrations in indoor environments with open windows and doors. In addition, the effect of the airflow mode of the air conditioner on the ...ventilation volume and indoor particle concentration variations was also measured. The ventilation fan could only provide approximately 43% of the ventilation volume during the design phase. The amount of ventilation differed depending on the opening area in windows and doors. The ventilation volume was increased by opening multiple windows or doors, even when the area of the opening was the same. No significant change in the ventilation rate was observed, although the air conditioner was expected to promote the ventilation rate in the room when set on blow mode. It was confirmed that both 0.3 and 1 μm particles could enter through the gaps around the windows and doors. Although most of the 5 μm particles were from the outdoor air, when the air conditioner was operated in airflow mode, the removal of 5 μm particles was performed by the air conditioner filter. The use of medium-performance or HEPA filters is expected to remove smaller particulates.
Currently, global warming is a growing problem around the world. As one of the solutions to this problem, the realization of a decarbonized society has been set as a goal. In the field of ...architecture, the spread of ZEH (Zero Energy Heating) is required to reduce the primary energy consumption to practically zero. Therefore, in this study, we clarified the efficiency of the reduction rate for each exterior skin performance, including lifestyle and regional climate characteristics. It also clarified the economic efficiency of photovoltaic power generation. In the comparison for window glazing, one of the results was that there was a pattern of performance improvements having a negative impact. Various results were obtained in which some areas were able to recover the cost of solar power even in severe climates and some areas were unable to recover the cost even in mild climates.
The purpose of this study is to investigate the most effective blowing method of underfloor air conditioning system from the viewpoint of comfort and ventilation performance using CFD simulation. In ...this study, we simulated three types of air blowing systems: floor radiation, floor-supply displacement air-conditioning, and floor chamber. Then, comfort was evaluated from thermal environment and PMV, and ventilation performance was evaluated from air age. As a result, the floor radiation system was able to maintain comfort. However, it was found that the floor-supply displacement air-conditioning system and the floor chamber system caused a great deal of discomfort because the temperature difference between the top and bottom was easily observed. In terms of ventilation performance, it was confirmed that ventilation was efficient in all methods. Of these, the floor-supply displacement air-conditioning system was found to be the most efficient.
We investigated the energy consumption of heat source equipment in the university research facility building. The purpose is to clarify the current operation state of the heat source facility and ...propose a more efficient heat source facility system at the time of renewal. The survey method used BEMS data to calculate every hour of COP used by the heat pump of electric energy, inlet and outlet temperature and primary pump flow rate. As a result, the heat source efficiency of the heat pump had an the average COP=1.98 during cooling in 2016 and COP=1.98 during heating in 2016.The heat source efficiency at the time of designing the heat pump was COP=2.38 during cooling and COP=1.95 during heating. Therefore, it was revealed that the heat source efficiency average in 2016 was lower than the heat source efficiency at the time of designing the heat pump. Also, energy simulation of the target building was carried out and the energy consumption was estimated. As a result, we grasped the detailed energy consumption of the target building.
This study aims to grasp the energy consumption of the government buildings currently being planned. The target building is the new government building in U City Japan, which is planned as a zero ...energy building for ZEB ready. In addition, considering the latest equipment to be introduced to the government building, energy simulation was performed using the Building Energy Simulation Tool (BEST) program. Simulation results revealed that the annual primary energy consumption was reduced by 30% below the reference value. In the future, the energy consumption will be further reduced by examining the methods for operation and control of the heat source equipment.
This study was investigated the building performance of each area for university facilities. The purpose is to propose optimal building performance for each area. As the background, the target ...building needs the energy-saving renovation. The target building has been built for 25 years and aged. In addition, the primary energy consumption of the target building is larger than the primary energy consumption of standard university facilities. Therefore, it is necessary to renovate buildings and facilities, and plans should be made to save more energy. This research method was examined changing the building performance for each area by using the Building Energy Simulation Tool (BEST) program of the energy simulation. Building performance is the thermal insulation of the outer wall and the type of glazing. As a result, In Ube, primary energy consumption tends to increase if thermal insulation performance is increased too much. In Sapporo, primary energy consumption tends to decrease as thermal insulation performance increases. In Naha, it turned out that increasing the thermal insulation performance is not effective.
The purpose of this study is to acquire data to examine the design method of radiant air conditioning in Japan. The radiant panels were installed in the population weather chamber, and the convective ...heat transfer coefficient and the radiant heat transfer coefficient on the upper side and the lower side of the radiant panel were experimentally calculated. As a result of this experiment, the radiant heat transfer coefficient was larger than the convective heat transfer coefficient during cooling and heating. In addition, CFD simulation of the thermal environment and airflow in the environmental control chamber was conducted. From the simulation results, it found that there was almost no temperature unevenness in the environmental control chamber, and the air flow was very small. There were differences in the comparison between the experimental values and the analysis values of the vertical temperature distribution.
We investigated the energy consumption of heat source equipment in the university research facility building. The purpose is to clarify the current operation state of the heat source facility and ...propose a more efficient heat source facility system at the time of renewal. The survey method used BEMS data to calculate every hour of COP used by the heat pump of electric energy, inlet and outlet temperature and primary pump flow rate. As a result, the heat source efficiency of the heat pump had an the average COP=1.98 during cooling in 2016 and COP=1.98 during heating in 2016.The heat source efficiency at the time of designing the heat pump was COP=2.38 during cooling and COP=1.95 during heating. Therefore, it was revealed that the heat source efficiency average in 2016 was lower than the heat source efficiency at the time of designing the heat pump. Also, energy simulation of the target building was carried out and the energy consumption was estimated. As a result, we grasped the detailed energy consumption of the target building.
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