공동주택의 에너지 소비량을 예측하기 위한 대표일 난방부하모델 개발에 관한 연구

김영탁 대한건축학회 2005 대한건축학회논문집 Vol.21 No.11

Heating load, in general, can be calculated with either a static or dynamic analysis method. However, there are some inherent problems in that the former method overestimates the true heating load, while the later requires more effort and time for analysis. For the improvement of these problems, it has been necessary to develop a simplified and more precise method of analysis, for use by architects and energy administrators when calculating heating load.For this purpose, we have developed a new estimation model; The Representing Day Heating Load Model. This is expressed with a one dimension linear function, compounded by N(the frequency of the representing day outdoor temperature) and DL(the representing day heating load). The model has been verified to estimate heating load within an error rate of ±3 percent.

지중가온이 온실의 난방부하에 미치는 영향

남상운 ( Nam Sang Woon ) 한국농공학회 2006 한국농공학회논문집 Vol.48 No.5

In order to examine the heat transfer characteristic of a soil warming system and effects of soil warming on the greenhouse heating load, control experiments were performed in two greenhouses covered with double polyethylene film. One treated the soil warming with an electric heat wire and the other treated a control. Inside and outside air temperature, soil temperature and heat flux, and heating energy consumption were measured under the set point of heating temperature of 5, 10, 15, and 20℃, respectively. Soil temperatures in a soil warming treatment were observed 4.1 to 4.9℃ higher than a control. Heating energy consumptions decreased by 14.6 to 30.8% in a soil warming treatment. As the set point of heating temperature became lower, the rate of decrease in the heating energy consumptions increased. The percentage of soil heat flux in total heating load was -49.4 to 24.4% and as the set point of heating temperature became higher, the percentage increased. When the set point of heating temperature was low in a soil warming treatment, the soil heat flux load was minus value and it had an effect on reducing the heating load. Soil heat flux loads showed in proportion to the air temperature difference between the inside and outside of greenhouse but they showed big difference according to the soil warming treatment. So new model for estimation of the soil heat flux load should be introduced. Convective heat transfer coefficients were in proportion to the 1/3 power of temperature difference between the soil surface and the inside air. They were 3.41 to 12.42 W/㎡℃ in their temperature difference of 0 to 10℃. Radiative heat loss from soil surface in greenhouse was about 66 to 130% of total heating load. To cut the radiation loss by the use of thermal curtains must be able to contribute for the energy saving in greenhouse.

시설원예의 지열냉ㆍ난방시스템 경제성 분석

류연수(Ryoo, Yeon-Su),주혜진(Joohye-jin),김진욱(Kim jin-wook),박미란(Park mi-lan) 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.6

Government Geothermal Cooling-Heating Projects has made efforts to reduce GHG(Greenhouse Gas) emissions and to manage cost of greenhouse farm house holds.This study evaluated the economic benefits of heating load rate of change by comparing Geothermal Cooling-Heating System with the existing system(green house diesel heating) in the Government Geothermal Cooling-Heating Projects. Economic analysis results shows that, 1)When installing the Cooling-Heating system according to the ratio of 70% heating load in policy standards, the geothermal cooling-heating system has economic efficiency with green house type or scale independent because the investment cost is recovered within 7 years. And It was more economic efficiency the ratio of 50% heating load than 70% heating load. 2)When installing the Cooling-Heating system according to the glass greenhouse of the ratio of 90% heating load, pay period of investment cost is recovered within 5 years. Therefore it is necessary to apply flexible heating sharing according to greenhouse type or scale.

공동주택의 최적 열공급을 위한 난방부하 예측에 관한 연구

김태호(Tae-Ho Kim),유성연(Seong-Yeon Yoo),한규현(Kyou-Hyun Han),윤홍익(Hong-Ik Yoon),강형철(Cheol-Hyeong Kang),김경호(Kyung-Ho Kim) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Prediction of heating load is necessary in order to determine the optimal scheduling control of district heating systems. Heating loads in apartment building are affected by many complex parameters, so it is necessary to develop high efficient, flexible, easy to use method of prediction of heating load. In this paper, parameters obtained from simple conditions included in apartment building specifications and the estimated temperature and humidity are used to predict the hourly heating load of the next day, and water load are predicted by comparing summer load with winter load. In order to validate the performance of the proposed method, heating load data measured form benchmarking district heating system are compared with the predicted results. As comparing predicted heating loads with measured data, monthly load error had a range from 0.06% to 18%, and in heating period, mean error was 4.68%

건물의 침기율 모델링에 따른 지중 열교환기 용량 산정의 불확실성

백승효 한국건축친환경설비학회 2022 한국건축친환경설비학회 논문집 Vol.16 No.1

The length of ground heat exchangers is a key factor in the stable operation of ground-source heat pump systems. Different design variables or parameters such as the thermal properties of the ground and heat pump efficiency are considered in sizing ground heat exchangers. Among these, building heating and cooling loads are one of the most significant. However, a variety of uncertain parameters in the building simulation process makes it difficult to reliably estimate building heating and cooling loads. This study investigated the effects of uncertainty in estimating building heating and cooling loads on the sizing of ground heat exchangers, by considering the impact of changes in infiltration rate on these load and consequently on the size of the heat exchanger. EnergyPlus 9.4 was used to estimate the heating and cooling loads of a mid-rise residential building and GLHEpro 5.0 was used to determine the total length of ground heat exchangers. The results show that an increase in the infiltration rate caused an increase in peak building heating and cooling loads. Consequently, the required length of ground heat exchangers calculated by each zone and model differ. Additionally, sensitivity of the size of ground heat exchangers to changes in infiltration rate varied with different patterns of peak and yearly building loads. Therefore, sensitivity analysis of the major parameters used for estimating building heating and cooling loads is needed to ensure that the sizing of ground heat exchangers is robust.

저에너지 공동주택 개별보일러의 출력범위 조절을 위한 난방 및 급탕부하 분석

김상엽(Kim, Sang-Yeop),장형문(Zhang, Xinwen),김찬희(Kim, Chan-Hee),최지수(Choi, Ji-Su),이규남(Rhee, Kyu-Nam),정근주(Jung, Gun-Joo) 대한건축학회 2021 대한건축학회논문집 Vol.37 No.11

In Korea, it is common to determine the capacity of individual gas-fired boilers based on the floor area or unit heating load of residential buildings. With this approach, the current tendency of heating load reduction can not be taken into account when sizing the individual gas-fired boilers for low-energy apartment buildings. Most of the low-energy apartment buildings might be equipped with over-sized boilers, which would cause the boiler to operate with low efficiency particularly under part load conditions. As the over-sized boilers can deteriorate the energy saving performance of low-energy apartment buildings, this study was conducted to suggest the necessity of adjusting the output range of individual gas-fired boilers. For this purpose, heating and domestic hot water load of apartment buildings were analyzed considering the historical change of energy saving design standards. The analyzed loads were compared with the output range of household gas-fired boilers currently available on the market. The results showed that the heating output of the boilers is over-sized, even though the heating load has been reduced by 53%. It was found that the part-load output of boilers was significantly higher than the heating load, which would lead to the reduced efficiency during the part load conditions. It was also found that the individual room control can increase the difference between the boiler part-load output and heating load. Therefore, it is necessary to adjust the output range of boilers by lowering the part-load output and to increase the turn-down ratio of boilers in order to improve the energy efficiency of low-energy apartment buildings.

Experimental study on the performance characteristics of a cylindrical heat pipe having a screen wick subject to multiple heat sources

Boo, Joon Hong,Kim, Hyun Gon Elsevier 2017 Applied thermal engineering Vol.126 No.-

<P><B>Abstract</B></P> <P>In a simple model to predict heat pipe performance, uniform thermal loads are assumed over heat transfer surfaces. The validity of the simple model is limited in many application areas such as electronics cooling and space thermal control, where a heat pipe is often subject to multiple, unequal thermal loads. This study aims to experimentally identify the performance of a cylindrical heat pipe under various multiple heat source configurations and thus to quantitatively estimate the deviation from a heat pipe under uniform conditions. The model heat pipe was 9.53mm in diameter and 0.6m in length, with a 0.4m evaporator. The working fluid and the container wall were water and copper, respectively, and a wire mesh screen was inserted as a capillary structure. The fluid charge ratios tested were 100% and 120% based on the wick void volume. The heat pipe was in gravity-assisted mode with an inclination angle of 45° to extend the range of thermal input. Five small heaters were installed in the evaporator with equal spacing, and the power inputs were controlled individually. Three different thermal load configurations were imposed: equal, increasing and decreasing distributions toward the condenser. The results were compared from the viewpoints of thermal resistance and effective thermal conductance. The thermal resistance of the heat pipe with a 100% fluid charge exhibited excellent values from 0.16K/W (at 50W) to 0.03K/W (at 300W) for a uniform heat load. However, those with multiple thermal loads resulted in almost a 100% increase for the lower thermal load, and up to a 40% increase for the higher thermal loads, depending on the configuration. The behavior of the heat pipe with a fluid charge of 120% exhibited little difference. The results herein can be employed to estimate the performance deviation of a heat pipe due to thermal load distribution.</P>

태안 시설원예단지의 온실 냉난방 부하 분석

서원명,배용한,허해준,곽철순,이석건,이종원,윤용철,Suh, Won-Myung,Bae, Yong-Han,Heo, Hae-Jun,Kwak, Cheul-Soon,Lee, Suk-Gun,Lee, Jong-Won,Yoon, Yong-Cheol 한국농공학회 2009 한국농공학회논문집 Vol.51 No.6

This study was conducted in the process that the basic plan of the formation of the thermal energy complex in the Iwon reclaimed land of Taean was being made. Targeting for the large-sized greenhouse to be made in this area, it examined the cooling and heating load and the amount of ventilation, and also analyzed the economic efficiency of heating. The research results are as per the below: The minimum ambient temperature of this area was measured on January 7, 2001, which was $-18.7^{\circ}C$, and the maximum ambient temperature of this area was measured on July 24, 1994, which was $36.7^{\circ}C$. The maximum heating load was 39,011 MJ/h, but the date when the maximum heating load was not consistent with the date when the minimum temperature was measured. The maximum cooling load was 88,562MJ/h, It was approximately 2.3 times of the maximum heating load, which was measured at 14:00 hours on September 4, 2000. The maximum amount of ventilation heat was 138,639MJ/h. Assuming the rate of solar heat use as 10%, 20%, 50%, and 100%, the total sum of cost-benefit would be ￦-193,450,000, ￦-634,930,000, ￦-3,372,960,000, and ￦-9,850,420,000, respectively 20 years later. The break-even point of the geothermal heat pump would be about 4 years for 10% use, about 3 years for 20% or 50% use, and approximately 6 years for 100% use. It was found that 50% use would be most advantageous. In case two systems are combined, the break-even point will be 10 years, 8 years, and 11 years respectively.

동시 냉난방 시스템 적용 건물의 에너지 절감을 위한 실시간 난방 온도 설정 프로세스 개발

이유진,이석현,신대욱 대한건축학회 2023 대한건축학회논문집 Vol.39 No.4

Simultaneous Heating and Cooling systems are advantageous when heating and cooling loads occur simultaneously in a building; the usage ofauxiliary heat sources is inevitable because the occurrence of the loads may vary. Since the auxiliary heat source has a lower COP than thesimultaneous heating and cooling systems, more energy is required when removing the same amount of load. To reduce energy, the usage ofsimultaneous heating and cooling systems and auxiliary heat sources must be increased and decreased, respectively. In this study, a processthat can determine the heating set temperature in real-time was proposed to increase the usage of simultaneous heating and cooling systemsfor buildings where the cooling load exceeds the heating load. This process determines the temperature for the next point using the heatingtemperature of the previous point and the energy inside the tank. These results confirmed that energy can be reduced while maintaining amore pleasant temperature. 동시 냉난방 시스템은 건물에서 난방 부하와 냉방 부하가 동시에 발생할 때 유리하다. 그러나 부하의 발생이 항상 동일하지는 않으므로 보조 열원의 사용이 불가피하다. 보조 열원 시스템은 동시 냉난방 시스템에 비해 COP가 낮기 때문에 동일한 양의 부하를 제거할 때 더 많은 에너지가 필요하다. 에너지를 줄이기 위해서는 동시 냉난방 시스템과 보조 열원의 사용량을 각각 증가시키고 감소시켜야 한다. 본 논문에서는 냉방 부하가 난방 부하보다 많이 발생하는 건물에 대해 동시 냉난방 시스템의 사용량을 증가시키기 위하여 난방 설정 온도를 실시간으로 결정할 수 있는 제어 프로세스를 제안하였다. 이는 이전 시점의 난방 온도와 탱크 내부의 잔여 에너지량을 파악하여 다음 시점의 온도를 결정하며, 보다 쾌적한 온도를 유지하면서도 에너지를 감소시킬 수 있음을 확인하였다.

동시 냉난방 시스템의 에너지 절감을 위한 실시간 냉난방 온도 설정 프로세스 개발

이유진(Lee, Yu-Jin),이석현(Lee, Seok-Hyun),신대옥(Shin, Dae-Uk) 대한건축학회 2023 대한건축학회 학술발표대회 논문집 Vol.43 No.2

Simultaneous Heating and Cooling(SHC) systems are advantageous when heating and cooling loads occur at the same time in a building. However, the usage of auxiliary heating and cooling systems are inevitable because of the variable occurrence of the loads. As the auxiliary system has a lower COP than the SHC system, when removing the same amount of load more energy is required. To reduce energy, the usage of SHC systems and auxiliary systems must be increased and decreased, respectively. As a way to balance the cooling and heating loads, Load Reset Control(LRC) methods have been proposed in previous study, however it is targeted at buildings where the cooling load is larger than the heating load. Therefore, to compensate for the limitations of LRC, this study aims to establish a control process that can increase the usage of SHC systems by changing the heating and cooling set temperature according to the real-time changing load.