Study on Variation of Internal Heat Gain in Office Buildings by Chronology

Abstract

Abstract:The additional process of load calculation during the retrofit of heating, ventilation, and air conditioning (HVAC) equipment has been generally omitted in Korea, in recent years. Instead, a simple replacement of HVAC equipment, based on existing HVAC capacities, has been used, which is limited when taking the variation of internal heat gain into consideration, due to changes in the consumption power due to light and office automation (OA) equipment in recent years. Thus, this study aimed to identify a change in internal heat gains over 30 years, from 1985 to 2015, study investigated actual measurement-based academic papers and catalogs about OA equipment, lighting, and the number of occupants per unit area. The heat load produced from OA equipment has increased by approximately 49.6% in 2015 compared to that of 1980, and the heat load from lighting equipment has decreased by 47% compared to that of fluorescent-based lighting, and the heat load from human bodies was approximately 10 W/m 2 on average, which showed a minimal change over the past 30 years. The internal heat gain calculated for 30,000 m 2 of total floor area has increased constantly for the last 30 years. Note that the internal heat gains were designed excessively, as the values used in literature was approximately 17% to 50% smaller than the value used normally in the case of pre-2000 designs, and the values used after 2000 were approximately 35% to 50% smaller than the design standard value.

A Study on the Changes in the Heat Source Capacity and Air-Conditioning Load due to Retrofit; Focusing on a Large Office Building in Korea

“…The internal heat sources were OA equipment, lighting, and human body heat. In a preceding study [6], the loads were calculated based on literature and catalogues. Table 6 shows the result of a survey on electricity consumption per unit of OA equipment and lighting.…”

“…However, as the service life of lighting and OA equipment ranges from three to five years, they are replaced frequently, which contributed to changes in the internal heat load. A preceding study [6] showed the quantitative picture of such changes.…”

“…The literature reviews concerning changes in building's internal loads, which correspond to STEP 1 in Figure 1, were conducted in a preceding study [6]. In this study, input values were applied to RTS-SAREK along with the study results by [6], as shown in Table 1. The design values reflected at the time of design, the actual measurement values, and the catalog values for equipment are noted items.…”

“…The study results concerning the internal heat load were applied from the results of the previous study [6], and the thermal transmittance, required to calculate the skin load, was applied by studying the design criteria such as the Building Acts in Korea at the time of construction. Also, based on the measurements in [14], the infiltration value per unit area of the window was applied.…”

“…These studies needed the verification of a complex simulation process and were limited to quantifying the practical level of input data with respect to buildings of the same category. In addition, the design criteria in Korea showed a difference when compared to the actual input levels [6,10], which required input data that was simple to apply and reflected the actual operation status of real buildings, and the maximum load, considering that the input data needed to be calculated.…”