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In relation to recent attention focused on the use of energy by lighting, there is a large potential for commercial buildings to save energy in this respect. The use of energy-saving bulbs or dimming controls triggered by daylight, not only enables lighting energy saving, but delivers cooling energy through a reduction in indoor heat production. In this study, we examine the energy use in commercial buildings by evaluating lighting energy saving methods and the effect of using dimmer controls with a heat control method, which can both maximize the cooling load reduction during summer and save energy. Results show that the total energy from the reference commercial building was reduced by 20.9% by replacing LFL T12 bulbs with LEDs, together with an additional saving of 19.9% in cooling energy by using the lighting heat & dimming control method. [ABSTRACT FROM AUTHOR]

The building-integrated coil-type ground-coupled heat exchanger (GCHE) was used to overcome the high installation cost of the heat exchanger. A field test and simulations were conducted to analyze the performance of GCHE when installed vertically or horizontally. The vertical GCHE refers to the coil-type GCHE installed at the center of a PHC (pre-stressed high-strength concrete) pile used for the building foundation. The horizontal GCHE refers to the coil-type GCHE laid horizontally on the bottom of the building. The amount of electric power consumed by the horizontal GCHE system was higher than that consumed by the vertical GCHE system. The coefficient of performance (COP) through a cooling experiment was identified as 3.9–4.3 for the vertical type and 3.3–3.7 for the horizontal type. The simulation model was used to examine the annual performance evaluation for the vertical and horizontal GCHEs. The comparison of the year-round energy consumption values showed that the vertical GCHE has about 15% higher heating/cooling efficiency than the horizontal GCHE. The return period was six years in both the horizontal and vertical GCHEs for the short term, but the cost saving in the vertical GCHE was about 28% higher in the long term. [ABSTRACT FROM AUTHOR]

Abstract: Geothermal energy has been provided to improve the energy performance of buildings with great support from the government in Korea. However, despite the many advantages of using a ground-coupled heat pump (GCHP) with geothermal energy, the high construction cost of the ground-coupled heat exchanger (GCHE) is the primary obstacle to prevent the supply and spread of GCHPs. In this study, in order to overcome the problems of the conventional GCHP, a GCHP integrated with a PHC (prestressed high-strength concrete) pile, which is used in the foundation of buildings, was introduced and its thermal performance was analyzed through experiments conducted in summer. To increase the thermal performance, a coil-type pipe was used. The PHC-pile-integrated GCHP was installed at a depth of 15m. However, because it was installed in the beneath of the building, it was not largely affected by the outdoor temperature. The measured effective thermal conductivity was 3.69W/m°C, which is similar to that of a conventional vertical GCHP. Also, the COP was determined to be 3.9–4.3, which is slightly lower than the conventional vertical GCHP. However, considering the fact that the expensive drilling cost could be mitigated by 83.7%, the thermal performances were satisfactory. [Copyright &y& Elsevier]