Solar energy would be the most important energy resource. The highest performance solar-energy receiver recorded utilizing 74.3 % of the solar energy in total of electricity and 40 °C hot water in summer, Yokohama, Japan, has already been reported in 2020 as a photovoltaic/Thermal (PV/T) solar panel. In this paper, the system design on introducing the PV/T solar panel to be a part of energy-supply system in a household and the simulation results are reported. Using a Monte Carlo simulation method, it can generate different energy demands at every 15 minutes through a year for various family members as the simulation calculation, while the results always follow the input existing statistics information. Not only solar-energy management in a household but also the environmental thermal load is evaluated. An example of the net-zero energy house having the best combination of the environmentally friendly PV/T and PV solar panels is presented in this paper.

Horizontal global solar radiation is important information for many industries, such as energy management for power grid and agricultural activity. This paper proposes an estimation method of horizontal global solar radiation using photovoltaic (PV) system for constructing of data base. The proposed method has two steps. Firstly, global solar radiation on tilted surface is estimated using by short-circuit current and open-circuit voltage monitored in PV system. Next, the solar radiation on tilted surface converts to the horizontal global solar radiation based on Erbs model. Accuracy of the proposed method has been verified by comparing the estimated values with measured value obtained by silicon pyranometer. The proposed method has the following advantages: (1) The estimation of the solar radiations that match the characteristics of crystalline silicon PV modules. (2) Increase in the number of the observation points due to the use of the PV system.