A residential cogeneration system (CGS) is highlighted because of its efficient energy usage on both the supplier and consumer sides. It generates electricity and heat simultaneously; however, there is insufficient information on the efficiency according to the condition of usage. In this study, we analysed the performance data measured by the home energy management system (HEMS) and the lifestyle data of residents in a condominium of 356 flats where fuel cell CGS was installed in each flat. The electricity generated by CGS contributed to an approximately 12% reduction in primary energy consumption and CO2 emission, and the rate of generation by the CGS in the electric power demand (i.e., contribution rate) was approximately 38%. The electricity generation was mainly affected by the use of electricity up to 4 MWh/household/year. Gas or water use also impacted electric power generation, with water use as the primary factor affecting the contribution rate. Electric power generation changes monthly, mainly based on the water temperature. From these results, we confirmed that a CGS has substantial potential to reduce energy consumption and CO2 emission in condominiums. Thus, it is recommended for installation of fuel cell CGS in existing and new buildings to contribute to the energy-saving target of the Japanese Government in the residential sector.
How much of energy saving effect is possible by residents' behavior must be important. But at least in Japan, it has not yet been made clear. Here in this research, we conducted a questionnaire survey on the residents' interests and lifestyle and thereby made the follow _ up analysis to figure out how the energy _ saving related consciousness, practice, and willingness are connected with each other. It has become clear that the information in relation to the problems to be solved or the willingness for making their levels of life higher is likely to let the respondents take actions.
In recent years, “green curtains” have become one of the most prevalent thermal mitigation methods in Japan. They can be considered as green infrastructure for achieving thermal comfort and reducing energy use. To examine the thermal mitigation effect of the green curtain for practical applicability in the condominium, the indoor and balcony temperatures for 48 days both in households with and without green curtains were analyzed. The balcony globe temperature of the households with green curtains was 0.6 °C lower than that of the households without green curtains, during air-conditioner usage. Furthermore, the air-conditioner usage time of the households with green curtains was 40% less than that of the households without green curtains. The results showed that green curtains are effective for achieving both thermal mitigation and energy saving in a condominium.
Controlling and reducing electric energy consumption is a critical issue across all over the countries for human wellbeing. However, approaches to achieve energy consumption reduction of individual occupants have not been established yet as both problems of collecting a large amount data of energy consumption and constructing prediction models are challenging. Here we show a case-study of energy consumption analysis, in which households with anomalous energy consumption can be completely detected using a questionnaire about their profiles without seeing actual energy consumption. Our approach is based on simple data mining techniques of outlier detection and decision trees, hence it can be easily implemented in the condominium housing market.
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