Design and Experiments of a Solar Low-temperature Hot Water Floor Radiant Heating System

The solar low-temperature hot water floor radiant heating system combines solar energy heating with floor radiant heating. This kind of environmental heating way not only saves fossil resources and reduces pollution, but also makes people feel more comfortable. First, the authors devised an experimental scheme and set up the laboratory. Second, we collected a great deal of data on the system in different situations. Finally, we conclude that such heating system is feasible and one of the best heating methods

Numerical Simulation of Thermal Performance of Floor Radiant Heating System with Enclosed Phase Change Material

In the present paper, a kind of enclosed phase change material (PCM) used in solar and low-temperature hot water radiant floor heating is investigated. On the basis of obtaining the best performance of PCM properties, a new radiant heating structure of the energy storage floor is designed,which places heat pipes in the enclosed phase change material (PCM) layer, without concrete in it. The PCM thermal storage time is studied in relation to the floor surface temperature under different low-temperature hot water temperatures. With the method of enthalpy , the PCM thermal storage time is studied under different supply water temperatures, supply water flows, distances between water wipe in the floor construction, floor covers and insulation conditions

Experimental Study of the Floor Radiant Cooling System Combined with Displacement Ventilation

As a comfortable and energy-efficient air conditioning system, the application of floor radiant heating system is used increasingly greatly in the north of China. As a result, the feasibility of floor radiant cooling has gained more attention. To examine the thermodynamic performance of the floor radiant cooling system, we measured the operational conditions including the minimum floor surface temperature, the cooling capacity, and the indoor temperature field distribution under different outdoor temperatures in Beijing. Because the ground temperature changes with the mean temperature of the supplied and returned water and room temperature, the mean temperature of the supplied and retuned water was obtained. Finally, we analyzed the phenomenon of dewing and developed measures for preventing it. The dry air layer near the floor formed by a displacement ventilation system can effectively prevent dews on the surface of the floor in the wet and hot days in summer. In addition, for the sake of the displacement ventilation system, the heat transfer effect between floor and space is enhanced. Our analysis pointed out that floor radiant cooling system combined with displacement ventilation ensures good comfort and energy efficiency

Combined Operation of Solar Energy Source Heat Pump, Low-vale Electricity and Floor Radiant System

Today energy sources are decreasing and saving energy conservation becomes more important. Therefore, it becomes an important investigative direction how to use reproducible energy sources in the HVAC field. The feasibility and necessity of using solar energy, low-vale electricity as heat sources in a floor radiant system are analyzed. This paper presents a new heat pump system and discusses its operational modes in winter

고단열丶고기밀 공동주택 온열쾌적 유지 및 난방에너지 저감을 위한 저온난방시스템 타당성에 관한 연구

학위논문(석사) -- 서울대학교대학원 : 공과대학 건축학과, 2022. 8. 여명석.According to relevant statistics, residential buildings such as apartments in buildings account for 43.4% of the energy consumption of the entire building sector. In addition to the energy consumption of the electrical system, the next most important energy consumption system is the heating system. By examining and analyzing the literature of related studies, this thesis discovered that, while the thermal insulation and tightness of apartment building envelopes have greatly improved in recent years, the heating load has been reduced to a relatively low level. Regardless of whether individual or district heating is used, hot water at a higher temperature is still used to transfer heat for the room through radiant floor heating panels to meet the indoor heating load. The strengthening of the thermal insulation of the envelope has led to a continuous decrease in the heating load of apartments, which provides theoretical possibilities for the application of low-temperature heating systems in residential buildings. Therefore, in this thesis, two low-temperature heating systems using individual gas boilers as heat sources and three low-temperature district heating systems were constructed by referring to the forms of related existing heating systems. To analyze the applicability of low-temperature heating systems in high - insulation high-tightness apartment buildings, a model of the relevant building and heating system was created using the dynamic simulation software EnergyPlus 9.5 as a research tool. For assessing the applicability of the low-temperature heating system, an assessment strategy was constructed from three perspectives: heating performance, thermal comfort, and energy consumption. Finally, according to the evaluation system, by comparing with the existing heating systems. The main results of this study are as follows. (1) It was confirmed that all low-temperature heating systems can meet the indoor heating demand. Floor surface temperatures and room temperatures tend to be lower than those of existing heating systems. And the floor surface temperature does not exceed the upper limit 29℃ required in the ASHARE HANBDBOOK. (2) Both low-temperature individual heating systems can improve the heating performance, low temperature individual heating system that use outdoor reset control to regulate water temperature can further improve heating performance. In the assessment about low-temperature district heating systems, it was found that the low-temperature district heating systems with HIU equipment has the most significant improvement in heating performance. (3) As the supply water temperature decrease, the low-temperature heating systems often require longer operating times to meet the indoor heating load. That is why individual low-temperature heating systems with outdoor reset control and district low heating systems with HIU have the longest operating times. In contrast to the runtime scenario, however, energy savings in the study period of the two longest-running low-temperature heating systems that use different heat sources are the most significant.관련 통계에 따르면 건물 내 아파트 등 주거용 건축물이 전체 건축부문 에너지 소비량의 43.4%를 차지하고 있다. 전기 시스템의 에너지 소비 외에 다음으로 주목할 만한 것은 난방 시스템의 에너지 소비이다. 본 논문은 관련 연구문헌을 살펴보고 분석함으로써 최근 아파트 건물 외피의 단열성능과 기밀성은 개선되는데 난방 부하가 상대적으로 낮은 수준으로 감소하였음을 발견했다. 하지만 개별 난방이든 지역 난방이든 상관없이 기준 난방시스템에서 높은 온도의 온수를 이용하고 복사 바닥 난방 패널을 통해 실내의 열을 전달하는 데가 유지하고 20세대 초반과 큰 변화는 없다. 외피 단열성능의 강화로 아파트의 난방 부하가 지속적으로 감소하면서 주거용 건물에 저온 난방 시스템을 적용할 수 있는 이론적 가능성을 제공하고 있다. 이에 본 논문에서는 개별 가스보일러를 열원으로 사용하는 저온 난방시스템과 기존 지역난방시스템을 참고하여 저온 지역 난방시스템을 구축하였다. 단열성과 기말성이 좋은 아파트 내 저온난방시스템의 적용가능성을 분석하기 위해 동적 시뮬레이션 소프트웨어 EnergyPlus 9.5를 연구 도구로 사용하여 해당 건물 및 난방시스템의 모델을 만들었다. 그리고 저온 난방 시스템의 적용 가능성을 평가하기 위해 난방 성능, 열적 쾌적성, 에너지 소비의 세 가지 관점에서 평가방범을 구축하였다. 마지막으로 평가 시스템에 따라 기존 난방 시스템과 비교하였다. 본 연구의 주요 결과는 다음과 같다: (1) 모든 저온 난방 시스템이 실내 난방 수요를 만족시킬 수 있음을 확인하였다. 바닥 표면 온도와 실내온도은 기존 난방 시스템보다 낮은 경향이 있다. 그리고 바닥면 온도는 ASHARE HANBDBOOK에서 요구하는 상한 29℃를 초과하지 않다. (2) 저온 개별 난방 시스템의 경우에서 난방 성능을 향상시킬 수 있으며, 실외 리셋 컨트롤을 사용하여 수온을 조절하는 저온 개별 난방 시스템은 난방 성능을 더욱 향상시킬 수 있다. 저온지역난방시스템에 대한 평가에서 HIU 장비를 갖춘 저온지역난방시스템이 난방성능을 가장 크게 향상시킨 것으로 나타났다. (3) 공급 온수온도가 낮아짐에 따라 저온 난방 시스템은 실내 난방요구를 만족하기 위해 더 긴 작동 시간을 필요로 하는 경우가 많다. 그렇기 때문에 실외 리셋 제어 기능이 있는 개별 저온 난방 시스템 및 HIU 기능이 있는 지역 저난방 시스템의 작동 시간이 가장 길다. 그러나 런타임 시나리오와 달리, 서로 다른 열원을 사용하는 가장 오래 지속되는 두 저온 난방 시스템의 연구 기간 중 에너지 많이 절약이 된다.Chapter 1. Introduction 1 1.1. Study Background and Purpose 1 1.2. Research Approach and Scope 4 Chapter 2. Preliminary Study 8 2.1. Changes in the heating load of Apartment in Korea 8 2.1.1 Development of thermal insulation of the building envelope 8 2.1.2 Changes in the heating load of Apartment 9 2.2. Existing space heating systems in Korea 12 2.2.1 Radiant Floor Heating System 14 2.2.2 Independent Heating with Individual Boilers 23 2.2.3 District Heating 30 2.3. Low-temperature Hydronic Heating Systems 36 2.3.1 Definition of low-temperature heating system 37 2.3.2 Low-temperature District Heating 40 2.3.3 Heat Interface Unit 42 2.4 Summary 45 Chapter 3. Research Subjects 47 3.1. Research Apartment Object 47 3.1.1 Apartment model for simulation analysis 47 3.1.2 Heating load analysis of object multi-family building. 51 3.2 Space heating system 55 3.2.1 Gas Boiler 55 3.2.2 Floor Radiant Heating Panel 56 3.2.3 Control for heating system 57 3.3 Assessment strategy 59 3.3.1 Heating Performance and Thermal Comfort 59 3.3.2 Energy Consumption 60 3.4 Summary 61 Chapter 4. Evaluation of the suitability of low temperature heating systems 63 4.1 Assessment Overview 64 4.2 Assessment of the suitability of individual low-temperature heating systems 70 4.2.1 Applicability evaluation of individual low-temperature heating systems with fixed supply water temperature 70 4.2.2 Applicability evaluation of individual low-temperature heating systems with outdoor reset control 78 4.3 Assessment of the suitability of district low-temperature heating systems 85 4.3.1 Applicability evaluation of district low-temperature heating systems with constant supply water temperature 86 4.3.2 Applicability evaluation of low-temperature district heating systems with outdoor reset control 91 4.3.3 Applicability evaluation of district low-temperature heating systems with heat interface unit 97 4.4 Summary 102 Chapter 5. Conclusion 105석

Experimental Research of an Active Solar Heating System

: Solar is an abundant renewable energy, which is used more and more frequently with the emphasis on environment protection, especially in building heating. The different devised methods between an active solar heating system and normal heating system are discussed in this paper. Based on the design, construction, testing and economic analysis of a demonstration project with the solar heating system, this paper discusses how to connect the solar energy collector with the electricity heater and heating system in order to achieve the best state of comfort and energy savings. The real cost of running is calculated and compared with that of other heating methods. The traits and the scope of applications of the solar heating system and the problems in designing, installing and operating are indicated in this paper

Capacity of Wood as Flooring Material: Improvement of Thermal Performance of Wood/Phase Change Material Composites

Wood is a biomaterial with good carbon fixation capacity. Phase change materials (PCMs) can impart thermal storage performances to materials. The goal of this study is to improve thermal performance by impregnating PCM into porous wood. The chemical stability of the composites was analyzed to evaluate whether it was appropriate for PCM to be impregnated into wood. Thermal performance of the composites was evaluated through latent heat analysis and thermal conductivity analysis. As a result of the analysis, the composites showed improved thermal performance compared to pure wood. In addition, in order to evaluate the applicability of the composites for floor heating, the dynamic heat transfer test was conducted using specimens as flooring material. As a result, it was confirmed that room temperature maintained the indoor comfort temperature range for longer time in rooms where composite specimens were applied as floor material. Result suggests that the composites can reduce the time for operating heating energy for floor heating. Thus, composites produced in this study proved to have the potential to be used as floor finishing material for floor radiant heating systems

Discussion of an Optimization Scheme for the Ground Source Heat Pump System of HVAC

With the implementation of the global sustainable development strategy, people pay more attention to renewable energy resources such as ground source heat pumps. The technology of ground source heat pump is widely applied to heat and cold. It is critical and important to know how to choose the terminal and make it workable. This paper makes a technical and economic comparison of various heating terminals (with the example of a north residential district which adopts ground source heat pump as the cold and heat source) and gets the optimum scheme

The influence of indoor microclimate on thermal comfort and conservation of artworks: the case study of the Cathedral of Matera (South Italy)

The Matera Cathedral was built in Apulian-Romanesque style in the thirteenth century on the highest spur of the “Civita” that divides “Sassi” district in two parts. The constructive material is the calcareous stone of the Vaglia, extracted from quarries in the area of Matera. The interior is Baroque and presents several artworks. The research had to evaluate the indoor microclimate during and after the restoration works, that also concern the installation of floor heating system to heat the indoor environments. Specifically, we have analyzed the thermal comfort and the effect that the artwork and construction materials inside the Cathedral of Matera have undergone

Study on the design of heating and energy saving of enclosure structure of rural self-built houses

For severe cold areas, indoor heating in winter is very important, and it is also important to achieve energy saving and emission reduction in the heating process. This paper briefly introduced a kind of heating envelope structure, the geothermal energy-based phase change wall, and analyzed two rural self-built houses in Shangluo city, Shaanxi province. One self-built house was built without the phase change wall, and the other was built with the geothermal energy-based phase change wall by the municipal government. The results showed that the self-built house that adopted the phase change wall had a better heat preservation effect and relieved the indoor temperature fluctuation; after the heating equipment was turned on, the self-built house that adopted the geothermal energy-based phase change wall had a higher and more stable indoor temperature, and the power consumption during the experiment was less