Abstract
Solar energy such as photovoltaic or solar heat is promising technology for reducing CO2 emission. Solar electricity and
solar heat are collected in daytime but thermal energy can be conserved easily. This paper describes about energy saving
potential of hybrid solar system, which consist of photovoltaic and solar water heater. In this study, we investigated the
effect of surface area of solar water heater and photovoltaic at canonical or cold climate area. The simulation results
showed us that the 1:0 or 3:2 of surface area ratio of photovoltaic and solar water heater have almost same energy saving
effect. The reduction rate of energy demand was 30.4% and 28.9% in the case of 1:0 and 3:2 of surface area ratio
respectively. In the canonical climate area, solar water heater can reduce the energy demand for room heating and hot water
supply. However, larger surface area of solar water heater brings excess heat supply in the mid or summer season.
Therefore, the contribution of solar water heater becomes relatively small compared to photovoltaic. In the cold area, the
contribution of solar water heater decreased due to attrition of solar irradiation in the winter season.
