Sustainable Building Energy Systems Laboratory

In South Korea, the building efficiency certification classifies building energy levels based on their required primary energy. The required primary energy for the building is calculated based on the design drawings in the energy of the system equipment. However, the required primary energy calculated based on the equipment in the design drawings is different from the measured required primary energy. Therefore, the measured required primary energy should also be evaluated when calculating the building energy efficiency level. In order to evaluate the measured required primary energy, it is necessary to analyze the actual energy use of the building. Therefore, this study conducted an analysis of the actual energy use of small-sized apartment buildings, which have recently been increasing in number. To achieve this, heating and electricity usage in apartment buildings usage was measured. This study analyzed the heating and electricity usage according to the area of apartment buildings, the number of residents, and the age of residents. As a result, heating and electricity usage of apartment buildings showed energy use characteristics according to the area, the number of residents, and the age of residents.

An office heating system is intermittently operated according to general occupancy patterns. When the heating system is not operated, heating load is accumulated in an indoor space, causing an decrease in an indoor air temperature. Because of this phenomenon, recovery times required when the heating system is restarted. The recovery time is affected by the heating system capacity and restart time. An excessive capacity causes increase in the recovery time and an insufficient capacity causes increase in an installation cost. Also, if the heating system restart time is set late, it may cause an worsening of the indoor thermal environment. Conversely, if the restart time is set early, it may cause unnecessary energy usage. Therefore, determining an optimal capacity and restart time is important, so this study evaluate the recovery time and energy usage according to various heating system capacities and restart times. To achieve this, an energy simulation was implemented using EnergyPlus with varying the heating system capacity and restart time. As a result, the recovery time varied between 46 379min. and daily energy consumption varied between 636.0, 879.7kWh with various heating system capacities. The recovery time varied between 53 118min. and daily energy consumption varied 675.4 869.8kWh with various heating system restart times.

ESS (Energy Storage System) stores the generated electricity power and supplies it when it is required. The ESS is attracting attention as a core technology for achieving the smart grid. Accordingly, the demand and importance of ESS are continuously increasing. In addition, the spread of ESS is increasing. However, as the spread of ESS increased, fires are also occurring. To prevent fire, the temperature of the ESS room must be kept stable. To achieve this, a cooling system is installed in the ESS room. However, additional energy consumption may be required contradicting the purpose of ESS operation. Therefore, this study evaluated the ESS thermal environment and energy effect.

본 연구는 외부차양 장치의 타입별 운용에 따라 창에서 발생하는 열전달 성분별 영향 분석을 통해 차양 장치의 열적 거동 특성을 평가하고자 하였다. 이를 위해 오피스 시뮬레이션 모델을 구축하고 에너지 해석과 열전달 특성 분석을 실시하였다. 본 연구의 결론은 다음과 같다. (1) 일간 복사 열전달 분석 결과, Basecase대비 Roller Type와 Venetian Type(0°)가 약 67%, Venetian Type(45°)가 약 48% 감소한 결과를 보였다. 이는, 차양 장치의 작동으로 인해 투과 일사가 차단되어 나타는 결과로 판단된다. 또한 Roller Type과 Venetian Type(0°)의 형상은 동일하지만 Roller Type의 경우 일사를 완벽하게 차단한 반면, Venetian Type(0°)의 경우 미세하게 복사에 의한 영향(약 5×10-17 W/m2~4×10-15 W/m2)이 존재하였다. 이는, Venetian Type의 슬랫 각도를 0°로 설정하여도 미세한 복사 열전달이 존재할 것으로 판단된다. (2) 일간 전도 열전달 분석 결과, Basecase대비 Roller Type이 약 24%, Venetian Type(0°)가 약 30%, Venetian Type(45°)가 약 26% 감소한 결과를 보였다. 일사의 영향이 없거나 작은 시간대에 열 손실이 발생하였으며 차양 장치가 작동하는 시간대에 열 획득이 나타났다. 이는, 창의 내·외부 표면온도 차이에 의한 결과로 확인된다. (3) 일간 대류 열전달 분석 결과, 실내 측 대류 열전달의 차이는 미미하였으나 실외 측 대류 열전달 차이는 변화하였다. 차양 장치가 작동하는 시간에 실외 측 대류 열전달은 Basecase대비 Roller Type이 약 54%, Venetian Type(0°)가 약 69%, Venetian Type(45°)가 약 71% 감소한 결과를 보였으며 이는, 대류 열전달 계수 변화와 외기온도?외부 표면온도 변화에 의한 결과로 확인되었다. 실외 측 대류 열전달 계수의 경우 Basecase 대비 Roller Type은 낮아진 값을 보인 반면, Venetian Type은 높아진 값을 나타내었다. 본 연구 결과를 통해 추후 창호 부위 열 성능 평가 및 성분별 영향도 분석에 도움을 줄 것으로 판단되며 나아가, 건물 부하 변동 및 건물에너지 절감 등을 위한 차양 장치의 정밀 제어에 관한 후속 연구가 필요할 것으로 사료된다.

The outdoor temperature reset (OTR) control method is widely used to control the setpoint temperature of heating supply water obtained from heat exchangers at mechanical rooms in an apartment building using district heating. In general, the OTR control consists of an algorithm that sets the maximum and minimum water setpoint temperatures based on the outdoor air temperature. The water temperature settings are very important variables when optimizing the performance of OTR control systems. However, in most apartment buildings these temperatures are arbitrarily determined according to the facility operator’s experience. Therefore, the purpose of this study is to determination the optimal setpoint temperatures for OTR control that also take into consideration heating energy consumption and load dissatisfaction. As a result, the optimal water setpoint temperatures for balancing each system’s thermal load dissatisfaction and heating energy consumption were 60.75℃ (maximum) and 45.75℃ (minimum) for four test cases examined in this study. In terms of applying the optimal setpoint temperatures, the consumption of energy was lower and thermal load dissatisfaction moderate as compared to the test cases. This study argue that OTR control using the optimal setpoint temperature will reduce heating energy and provide a stable thermal load.

최근 비정형 건축물의 비중이 증가함에 따라 거푸집 재사용이 불가하여 건설폐기물이 증가하고 있는 추세이다.또한 비정형 건축물 건축 시 생산자의 숙련도에 따라 비정형 패널의 품질이 결정되며 이에 따른 정확한 공사비 측정불가 및 인건비 증대라는 문제점이 있다. 본 연구는 이러한비정형 건축물의 문제점을 보완하기 위하여 오차율이 적고작업성이 좋은 최적의 배합을 찾는 것을 목표로 실험을 진행한다.

Among various types of geothermal heat pump systems, Vertical Closed-Loop Geothermal Heat Pump (VGSHP) has received increasing attention due to a variety of advantages such as the potential to be installed in a relatively small space and improved energy efficiency. In this research, the performance of VGSHP system coupled with heat storage tank was evaluated, by analyzing operational behavior of heat storage tank, the variations of heat pump energy performance due to the connection with heat storage tank, part load ratios characteristics of heat pump and the corresponding energy cost, compared to chiller and boiler based conventional system. The results of this study showed that the VGSHP system coupled with heat storage tank showed an energy saving effect of about 18% for cooling and about 73% for heating, and annual heating/cooling energy cost reduction of 43,000,000 KRW ($ 39,000), compared to the conventional air conditioning system. In addition, after considering both energy cost and initial investment cost including equipment, installation and auxiliary device expenses, payback period of approximately 11.8 years was required.

In this study, the effects of considering hourly metabolic rate variations for predicted mean vote (PMV) control on the heating and cooling energy and greenhouse gas emission were investigated. The case adopting PMV control taking the hourly metabolic rate into account was comparatively analyzed against the conventional dry-bulb air temperature control, using a detailed simulation technique. Under the assumption that all the apartments in Korea adopt the PMV control incorporating real-time metabolic rate measurements, nationwide reductions of primary energy and greenhouse gas emission were analyzed. As a result, PMV control considering hourly metabolic rate variations is expected to reduce national primary energy by 6.2% compared to conventional dry-bulb air temperature control, corresponding to reduction of 10,342 GWh. In addition, it turned out that 6.6% of tCO2 emission can be reduced by adopting PMV control, corresponding to nationwide reduction of greenhouse gas emission by approximately 1,720,000 tCO2.

In this study, the technologies and regulations for distributing standing column well(SCW) ground source heat pump systems to the residential cluster homes were investigated. They have only been installed in the public or commercial building having different load pattern and site structure compared with the residential cluster homes. Some of SCWs for the residential cluster homes should be installed under the basement due to a lack of site area. There are pressure differences between the SCWs installed under ground surface and basement. It is needed to develop the technology or devices to prevent overflow caused by pressure difference among the SCWs. In addition, heat balance algorithm between SCWs should be adopted to maximize the system efficiency. A heat pump having heating, cooling, hot water, heating-hot water, and cooling-hot water modes should be developed for adopting an individual air-conditioning system to the residential cluster homes.

국내 하절기 전력사용량은 2016년 8,000만kW을 돌파하였고, 하절기 전력사용량과 피크부하는 지속적으로 증가하고 있다(산업통상자원부, 2016). 이에 대한 대책으로 신재생에너지 활용에 대한 관심이 증대되고 있다. 특히, 재생에너지 3020정책에 따라 건물 부문에서의 PV시스템(Photovoltiac System)은 주요 정책으로 부상하고 있다. 산업통상자원부(2017)에 따르면 2030년 까지 PV시스템 비율을 전체 신재생에너지의 약 57% 이상을 차지할 것으로 계획하고 있다. 정부에서도 PV시스템에 대한 지원 및 대여 사업을 활발히 진행중에 있으며 PV시스템의 성능향상 및 효용성 개선을 위한 R&D 연구까지 그 범위가 확대되고 있다. 특히 PV시스템의 효율 개선 문제는 PV시스템 보급 목표를 달성하기 위한 가장 중요한 요소중 하나이다. PV정격효율은 STC(Standard Test Condition)조건에서 결정되지만, 실제 PV운용효율은 NOCT(Nominal Operating Cell Temperature)조건에서의 성능평가를 수행해야 한다. 그러나 실제 PV운용효율은 모듈표면온도 변화에 따라 달라지며 일반적으로 모듈표면온도는 외기온도, 일사량, 그리고 풍속에 의해 영향을 받는다. 따라서 하절기 PV시스템 실질적 성능평가에 있어 모듈표면온도 예측 및 분석은 선행되어야 하며, 모듈표면온도에 영향을 주는 외부 인자와 발전량과의 상관관계 분석 또한 요구된다. 이에 본 연구에서는 대표적 모듈표면온도 계산 알고리즘 결과와 실측 데이터와의 비교 분석을 실시하였다. 이를 통해 계산 알고리즘의 외부 인자 변화에 따른 민감도와 정확도를 평가하였다.

In this study, the present regulation of heat metering for the ground source heat pump was investigated.The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.