Phase change materials (PCMs) have been considered as an innovative technology that can reduce the peak loads and heating, ventilating and air conditioning (HVAC) energy consumption in buildings. Basically they are substances capable of storing or releasing thermal energy as latent heat. Because the amount of latent heat absorbed or released is much larger than the sensible heat, the application of PCMs in buildings has significant potential to reduce energy consumption. However, because each PCM has its own phase change temperature, which is the temperature at which latent heat is absorbed or released, it is important to use an appropriate PCM for the purpose of building envelope design. Therefore, this paper aims to investigate the energy saving potentials in buildings when various PCMs with different phase change temperatures are applied to a lightweight building envelope by analyzing the thermal load characteristics. As results, the annual heating load increased at every phase change temperature, but the peak heating load decreased by 3.19% with heptadecane (phase change temperature 21 °C), and the lowest indoor temperature increased by 0.86 °C with heptadecane (phase change temperature 21 °C). The annual cooling load decreased by 1.05% with dodecanol (phase change temperature 24 °C), the peak cooling load decreased by 1.30% with octadecane (phase change temperature 29 °C), and the highest indoor temperature dropped by 0.50 °C with octadecane (phase change temperature 29 °C). When the night ventilation was applied to the building HVAC system for better passive cooling performance, the annual cooling load decreased by 9.28% with dodecanol (phase change temperature 24 °C), the peak load OPEN ACCESSEnergies 2013, 6 5220 decreased by 11.33% with octadecane (phase change temperature 29 °C), and the highest indoor temperature dropped by 0.85 °C with octadecane (phase change temperature 29 °C).

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To develop an energy-efficient low-temperature radiant floor heating system in an apartment housing unit from an improved the overall heating system efficiency perspective, it is essential to consider the occupants' thermal comfort and evaluate the thermal environment and thermal output of the radiant panel. This study evaluated the heating performance of a low temperature radiant floor heating system by monitoring the water flow rates, supply and return water temperatures, indoor room temperatures and floor surface temperatures through field measurements, and surveyed the occupants' thermal comfort through questionnaires. Based on the results of field measurements and the occupants' questionnaires, the heating performance and thermal comfort sensation of a low-temperature radiant floor heating system were analyzed. The design considerations of a low temperature radiant floor heating system are suggested.

Automated blind control has been found to be more effective in controlling solar penetration than manual blind operation. Existing automated blind control methods mainly focus on improving indoor conditions, but considering the outside obstructions may offer a potential method to admit diffused solar radiation, reducing lighting, cooling, and heating demands. Accordingly, in this study, blind control considering surrounding buildings (BCCSB) was applied to determine potential demand reductions considering 20 736 cases of different surrounding building heights, orientations, locations, and climate change projections using EnergyPlus. The results demonstrate that BCCSB can reduce lighting demand by up to 30% when the building obstruction angle is greater 30°; however, this reduction decreased as the angle factor between the fenestration surface and sky decreased due to the accompanying reduction in admitted diffused solar radiation. The reduction in lighting demand also reduced the cooling demand as fewer active lighting fixtures were required. The use of BCCSB did not significantly reduce heating demand. The BCCSB can thus facilitate the reduction of lighting and cooling demand in highly glazed buildings, especially in warm climates. This evaluation of the positive effects of BCCSB can help to develop related design guidelines, standards, and practices for automated blind control strategies.