• Energy Research

Abstract The concept of zero-energy buildings is gaining much interest, and its technical feasibilities have been demonstrated for sustainable development. Although several case studies present how effectively zero-energy performance can be achieved, there is still a lack of data understanding adopting different combined passive and active systems for zero-energy performance. In response to this gap, this study introduces new integrated systematic approaches of enabling all-electric zero-energy performance and presents these features and operating performance for each part of energy consumption contributors based on measured data over two years. Structural insulation panels, vacuum glazing with heated glass were applied as passive techniques. An air-source heat pump and package air conditioner were used for heating and cooling systems, respectively. In addition to the passive and active systems, building-integrated solar thermal and roof-integrated photovoltaic (RIPV) systems were installed to offset all the remaining energy in the house. The energy use intensity of the house was 77.98 kWh/m2·yr; heating and domestic hot water had the highest consumption. To save cooling consumption, exterior electric venetian blinds and natural ventilation were used to cut down energy consumption. The house consumed 7,368.95 kWh/yr and produced 11,439.68 kWh/yr through the RIPV, the annual RIPV surplus accounting for 35.58 % of the annual energy production. The results from this case study provide a comprehensive overview of the feasibility of different combined technologies and insights into proper design strategies to improve the performance of zero-energy houses and buildings from another point of view.

The performance of the Operable Building Integrated Photovoltaic (OBIPV) system applied to the building envelope to reduce the building energy consumption varies significantly depending on the operation method and influence of the surrounding environment. Therefore, optimization through performance monitoring is necessary to maximize power generation of the system. This study used temperature-corrected normalized efficiency (NE*) to evaluate the power generation performance of the operation methods and predict that of the OBIPV system based upon the measured data. It was confirmed that power generation performance decreased when the photovoltaic (PV) operation angle changed, the system remaining the same. A decrease in power generation performance due to partial shading from an overhang was also observed. As a result of the power generation prediction for two months using NE*, the error of the measured values was found to be less than 3%. In addition, with or without any partial shading of the OBIPV system, its performance degradation was predicted with an annual electricity generation decrease by 36 kWh/yr (6.5%). Therefore, NE* can be used as an indicator for evaluating the power generation performance of PV systems, and to predict generation performance considering partial shading.