Cities all over the world have been warming up in the summer over the years. Seoul, the capital of Korea, is also an example of a city which has been transformed into an urban heat island. Green areas produce social, economical, and environmental benefits in highly populated urban areas. This study is to investigate the micro—climate changes and urban—scale cooling load reduction by the recently restored Cheonggye stream, also known as Cheonggyecheon, in Seoul. Since the urban developments of the 1950's, the Cheonggye stream, located in central Seoul, has been covered with pavement and concrete overpass structures for over 50 years. A lot of surrounding buildings, traffic, and people caused the Cheonggye stream area to get hotter than other districts. For the urban environmental renovation, the 5.84 km—long stream was restored in September 2004. Since the restoration, the ecosystem in the center of Seoul has been reviving. This simulation study analyzes the micro—climate changes in the restored Cheonggye stream and its surroundings by using Envi—Met, a microclimate model designed to simulate the surface—plant—air interactions in an urban environment. We employed TRNSYS to estimate the urban—scale cooling load reduction by using the output data from the Envi—Met simulation. The results indicated that the cooling benefits of the restored stream areas are promising in the locations where the environment was restored.

This paper examines the effectiveness of South Korea’s policy for reducing greenhouse gas (GHG) emissions in office buildings and evaluates if national targets can be met. A sample of office buildings was categorized into two groups—conventional (Group A) and new (Group B)—based on when their construction was approved. Furthermore, data regarding the three design elements of the building envelope, that is building form, window systems, and U-values were collected. By statistically processing data of each element, reference building models were developed and a case study was conducted for each building. Design changes that were incorporated, keeping in mind the GHG reduction policy, showed 13.1% of saving energy in case 8 (reference building of Group B) than case 1 (reference building of Group A). The savings in case 8 were more than the average GHG reduction rate (12.8%) compared to business as usual (BAU). However, case 4 (a conventional (Group A) building form with new (Group B) window systems and U-values) achieved the greatest savings in building loads. The policy to enhance insulation in new buildings to reduce GHG emissions in the building sector has prompted changes in building forms and window systems and has reduced emissions by 10%, that is 3% more than the expected value. Thus, new innovations in building envelope design could achieve an average 12.8% reduction in emissions in buildings.

In this study a quantitative analysis was performed on the effect on thermal comfort of the stand fan, a personal cooling device that creates local air currents. A total of 20 environmental conditions (indoor temperatures: 22, 24, 26, 28, and 30 °C; fan modes: off, low (L) mode, medium (M) mode, and high (H) mode) were analyzed using questionnaires on male and female subjects in their 20s and a thermal manikin test. The contents of the questionnaire consisted of items on thermal sensation, thermal comfort, thermal acceptability, and demands on changes to the air velocity. This step was accompanied by the thermal manikin test to analyze the convective heat transfer coefficient and cooling effect quantitatively by replicating the stand fan. Given that this study provides data on the cooling effect of the stand fan in quantitative values, it allows for a comparison of energy use with other cooling systems such as the air conditioner, and may be used as a primary data set for analysis of energy conservation rates.

Two experiments were executed to examine the slice accelerated test method, suggested in ISO 11561 “Ageing of thermal insulation materials—Determination of the long-term change in thermal resistance of closed-cell plastics (accelerated laboratory test methods)” and to observe the changes in the thermal performance of insulation material over time by the real-time ageing process. The accelerated test method was conducted for 120 consecutive days using 10 mm thick-sliced specimens, which were sampled from a 50 mm thick plate body. The real-time ageing process was performed for 5000 consecutive days under constant temperature and relative humidity conditions as of 20 ± 5 °C and 50 ± 5% without any slicing. Degradation of thermal performance was shown to be stabilized at around 38 to 41% down from the initial values, which were correspondent with the approximately 10 days after the initial time. The real-time ageing process revealed similar degradation levels at around 130 days after the starting point. Converting the results using the scaling method specified in ISO 11561, the change was found in the range of 37 to 41% for the thermal resistance after 25 years and of 30 to 38% for the 25-year-average thermal resistance, respectively. Within the 10% error range, both the accelerated method and real-time ageing resulted in a similar level of degradation. Consequently, it was our observation that the slice accelerated test was quite enough to predict the practical degradation of insulation materials with at least 90% of accuracy under the specified time duration, temperature and thickness satisfactions.

This study aims to improve the thermal environment of buildings and their occupants’ relative performance (RP) by having buildings exploit energy for cooling from energy saved when building controls are in place. Many countries restrict indoor set-point temperatures based on energy-saving policies, although such restrictions can compromise occupants’ thermal comfort and, in turn, their RP. This study first sets the existing building energy consumption, which limits indoor temperature settings in accordance with energy-saving policies, to baseline. The study then proposes a method to find an optimal hourly set-point temperature that represents the same energy consumption as the baseline—an optimal indoor-temperature-setting method that improves the RP of occupants while keeping the same energy consumption as the baseline. In this study, the time (hour) included in the thermal comfort range has increased from 0 h to 2 h, which consequently improved RP by 0.2% to 0.4%. This result indicates that the proposed approach is a cost-effective way to improve the RP of occupants without the additional consumption of energy by their buildings. The approach is ultimately applicable to building energy management systems as a method to improve the RP of occupants in buildings in which additional energy consumption relative to existing energy consumption presents a challenge.