节能建筑用蓄热材料的释热性能实验研究

相变材料在发生相变的过程中吸收或者释放热量，在太阳能利用、建筑节能和空调采暖方面有着广阔的应用前景。通过实验研究了可用于节能建筑的相变材料——硫酸钠水合盐体系相变材料的释热性能，研究了不同增稠剂和成核剂对其放热性能的影响，对节能建筑用相变建材的研究有参考价值。     

Application of energy storage enclosure with phase change materials in building energy saving

相变材料具有高效的能量储存功能。相变材料与建材基体结合,制成一种具有储热功能的围护结构。该围护结构可发挥相变储热功能,降低建筑室内温度波动,增强建筑热舒适度,能够更加有效地减少建筑物运行能耗,从而实现建筑节能。本文对当前现有相变材料的优缺点、相变材料在不同围护结构中的应用、相变储能围护结构对室内热环境的影响及对建筑运行能耗的影响、相变储能围护结构应用的经济性等方面进行了分析,提出相变储能围护结构在工程应用中所存在的不足及其发展前景。     

Turbine inlet cooling with thermal energy storage

Turbine inlet cooling (TIC) is a common technology used to increase combustion turbine power output and efficiency. The use of mechanical or absorption chillers for TIC allows for more air cooling than evaporative methods and also imposes a significant parasitic load to the turbine. Thermal energy storage (TES) can be used to shift this load to off‐peak hours. Use of thermal storage increases the flexibility of turbine power output, which benefits from the application of optimization tools. This paper explores the effect of combining TIC with TES to enhance the performance of a district cooling system that includes a gas turbine for power generation. The work illustrates how the system's performance can be enhanced using optimization. Application of multi‐period optimization to the system that includes TES brings significant operational cost savings when compared with a system without thermal storage. It is also shown how TES provides demand‐side energy management in the district cooling loop and supply‐side management through the use of TIC. In addition to the optimization study, a thorough literature review is included that describes the current body of work on combining TIC with TES. Copyright © 2013 John Wiley & Sons, Ltd.     

Heating and cooling of a hospital using solar energy coupled with seasonal thermal energy storage in an aquifer

A system is being designed, using solar energy in combination with Aquifer Thermal Energy Storage (ATES), that will conserve a major part of the oil and electricity used for heating or cooling the Cukurova University, Balcali Hospital in Adana, Turkey. The general objective of the system is to provide heating and cooling to the hospital by storing solar heat underground in summer and cold in winter. As the main source of cold energy, ventilation air at the hospital and surface water from the nearby Seyhan Lake will be used.     

Energy efficient building strategies for school buildings in Oman

In this paper hour-by-hour computer simulations of cooling load for a public building were carried out under local weather conditions using TRNSYS building computer simulation software. Different passive measures to reduce the cooling load were investigated. These include the envelope insulation, space ventilation, shading, glazing, artificial lighting variation, and evaporative cooling of the structure. The results show as high as 43% reductions in peak cooling load can be achieved using a combination of well-established passive cooling techniques and technologies. The significance of these results stems from the fact that they were obtained under local weather conditions, a matter of importance to building architects, designers, contractors, and builders as well as air-conditioning equipment manufacturers. Although this work was undertaken to improve the thermal performance of school buildings the results were extended to cover the summer school vacation months so that they will benefit public buildings as well. Copyright © 2002 John Wiley & Sons, Ltd.     

Adjustable insulation for enhancing the performance of phase change materials in buildings

The energy savings of a building roof integrated with a phase change material (PCM) and different insulation strategies are presented in this paper. The proposed roof structure includes a concrete slab with a PCM layer and an air cavity insulation, which can be adjusted according to certain strategies. The adjustable insulation is devised to enable a reduced total heat gain throughout 24 h in summer days, thereby improving the performance of the PCM. The heat gain/loss through the roof with the PCM layer and adjustable insulation is compared with that of the roof with the PCM layer and fixed insulation during a typical year in Hangzhou, China. The effects and optimization of the melting temperature of the PCM are also explored. The simulation results show that, overall, the adjustable insulation can reduce the daily heat flux through the roof by approximately 20% compared with the conventional fixed insulation.     

Energy saving in building with PCM cold storage

This article presents an experimental and numerical analysis of cooling buildings using night‐time cold accumulation in phase change material (PCM), otherwise known as the ‘free‐cooling principle’. Experimental and numerical studies of the ceiling and floor free‐cooling principle, as well as passive cooling, are presented. The free‐cooling principle is explained and some of the types of PCMs suitable for summer cooling are listed. An experiment was conducted using paraffin with a melting point of 22°C as the PCM to store cold during the night‐time and to cool hot air during the daytime in summer. Air temperatures and heat fluxes as a function of time and dimensionless cold discharging values are presented for different air velocities. Experimental analysis of one week of measuring under real conditions is presented in order to show how cold storage functions. Copyright © 2007 John Wiley & Sons, Ltd.     

Review and selection of EPCM as TES materials for building applications

In order to improve the thermal efficiency of building thermal energy storage (TES) systems, the feasibility of using encapsulated phase change materials (EPCMs) as heat storage media is analysed in this work. Specifically, the finite element method is used to perform thermal behaviour analyses of several EPCMs. These analyses include technical and economic assessments in order to identify the best combination of PCM and shell material, using as main parameters: thermal energy storage, heat transfer rate, materials cost, among others. The results show that EPCMs composed by Na₂SO₄·6H₂O as PCM and covered by stainless steel highlight as TES materials.     

采暖居住建筑节能改造热工性能分析

本文对我国华北地区既有采暖居住建筑节能改造前后围护结构的非稳态热工性能进行了分析,计算结果表明,既有建筑节能改造后围护结构内壁温与室内温差减小且波动幅度降低,围护结构的热稳定性、热舒适性均有所提高。     

On the technical feasibility of gas turbine inlet air cooling utilizing thermal energy storage

The potential of using thermal energy storage (TES) in the form of ice or chilled water to cool gas turbine inlet air is evaluated for a remote oil field location in the Sultanate of Oman using local hourly typical meteorological year weather data. It is found that under the conditions investigated seasonal TES in chilled water storage tanks or ice bins for the location considered is prohibitively expensive and thus not recommended. Application of partial TES option shows that the cool storage does not result in any noticeable reduction in the chiller size. Hence, TES whether seasonal, partial, or full storage is not a viable option for the considered location, especially in the absence of time‐of‐use utility rate structure. Copyright © 2005 John Wiley & Sons, Ltd.     

Free cooling of a building using PCM heat storage integrated into the ventilation system

This article presents a study of the free cooling of a low-energy building using a latent-heat thermal energy storage (LHTES) device integrated into a mechanical ventilation system. The cylindrical LHTES device was filled with spheres of encapsulated RT20 paraffin, a phase-change material (PCM). A numerical model of the LHTES was developed to identify the parameters that have an influence on the LHTES’s thermal response, to determine the optimum phase-change temperature and to form the LHTES’s temperature-response function. The last of these defines the LHTES’s outlet-air temperature for a periodic variation of the inlet ambient-air temperature and the defined operating conditions. The temperature-response function was then integrated into the TRNSYS building thermal response model. Numerical simulations showed that a PCM with a melting temperature between 20 and 22 °C is the most suitable for free cooling in the case of a continental climate. The analyses of the temperatures in a low-energy building showed that free cooling with an LHTES is an effective cooling technique. Suitable thermal comfort conditions in the presented case-study building could be achieved using an LHTES with 6.4 kg of PCM per square metre of floor area.     

Photo-to-thermal conversion and energy storage of lauric acid/expanded graphite composite phase change materials

To make better use of solar energy, lauric acid/expanded graphite (LA/EG) composite phase change materials (PCMs) were synthesized to collect and store solar energy as latent heat thermal energy. The results of thermal characteristics show that when the mass fraction of EG is 5%, 10%, and 15%, the latent heat of LA/EG is 164.5, 156.9, and 148.0 J/g, and the thermal conductivity is 2.73, 7.98, and 10.54 W/(m·K). Leakage test shows that LA/EG PCMs with EG mass fraction of 10% and 15% are form stable after phase change. One thousand thermal cycles prove good thermal reliability of LA/EG. TG analysis indicates LA/EG PCMs have good thermal stability within operating temperature range. The Ultraviolet-visible spectra reveal that the absorbance of LA/EG composite PCMs would increase as the mass fraction of EG increases. Photothermal conversion experiment results indicate that the photothermal conversion efficiency of LA/EG composite PCMs increases as the mass fraction of EG increases, and the efficiency can reach 95% when the mass fraction of EG is 15%. Moreover, it was also found that the process of photothermal conversion can be accelerated with stronger illumination intensity or smaller heat transfer size. All the results show that the prepared LA/EG PCMs can convert solar energy into thermal energy and store it in the form of latent heat at the same time, which indicates it has promising prospect in the application of solar energy conversion and storage.     

上海市《公共建筑节能设计标准》分析

对上海市《公共建筑节能设计标准》(DGJ08-107-2004)和其它建筑节能设计标准作了简单分析与比较。并针对节能设计的现状提出了一些建议,认为对于一些成熟有效的节能措施应通过节能设计标准的规定性条文加以推广。     

Performance analysis of phase-change material storage unit for both heating and cooling of buildings

Utilisation of solar energy and the night ambient (cool) temperatures are the passive ways of heating and cooling of buildings. Intermittent and time-dependent nature of these sources makes thermal energy storage vital for efficient and continuous operation of these heating and cooling techniques. Latent heat thermal energy storage by phase-change materials (PCMs) is preferred over other storage techniques due to its high-energy storage density and isothermal storage process. The current study was aimed to evaluate the performance of the air-based PCM storage unit utilising solar energy and cool ambient night temperatures for comfort heating and cooling of a building in dry-cold and dry-hot climates. The performance of the studied PCM storage unit was maximised when the melting point of the PCM was ～29°C in summer and 21°C during winter season. The appropriate melting point was ～27.5°C for all-the-year-round performance. At lower melting points than 27.5°C, declination in the cooling capacity of the storage unit was more profound as compared to the improvement in the heating capacity. Also, it was concluded that the melting point of the PCM that provided maximum cooling during summer season could be used for winter heating also but not vice versa.     

Artificial intelligence implementation framework development for building energy saving

In this study, artificial intelligence (AI) control tools were developed to construct an AI implementation framework for energy saving for buildings. Although numerous AI studies related to energy conservation have been conducted, most of them have reported computing algorithms and control effects for single objects. This is the first study to use a framework to integrate five-category AI control tools to execute three-level building energy conservation; the three levels consist of equipment-level control, facility-level control, and whole building energy saving. Energy-saving effects were tested in a real building. The complex three-floor building primarily with a total area of 9072 m² serves as an office space and a semiconductor production line. Seventy percent energy consumption comes from air conditioning system and motor power. Twenty percent is lighting system and the other 10% is plug power and office automation equipment. Before implementation, the yearly energy cost reached US$1004339. In 2018, an AI implementation framework was introduced to systematically deploy AI at the site. A total of 47.5%, 37%, and 36.9% of energy was saved at equipment, facility, and whole building levels; up to US$385203 was saved. These energy savings proved the feasibility of the implementation framework. Furthermore, unmet demands of AI studies were met, and an approach to fill the research gap is discussed.     

Weather data for building energy cost-benefit analysis

This paper deals with European TRY weather data processing for climatic indexes generation, useful for HVAC energy and cost simplified evaluation. For nine Italian locations are presented: 99 and 2·5% dry bulb temperatures, 2·5% wet bulb temperatures, heating and cooling degree days, latent enthalpy days, unitary sensible and latent loads. TRY psychrometric data were processed according to a bin method that preserves the correlation between dry bulb temperature and moisture content, and then reduced by an averaging technique. An example is worked out in order to present an engineering shorthand for energy and cost evaluation of HVAC system. © 1998 John Wiley & Sons, Ltd.     

蓄能型液体除湿蒸发冷却系统中除湿性能的实验研究

提出了一种新型空调系统——液体除湿冷却空调系统的设计方案并搭建一功率为3kW的实验台，考虑到除湿过程和再生过程是该系统性能优良的决定性环节，设计加工了水冷型波纹板降膜式结构的除湿器和以丝网填料作为内部填料的再生器。在此实验装置上对系统的除湿过程以及其蓄能能力特性进行了实验研究，得出影响该系统除湿能力、蓄能能力等方面的主要因素，为系统的优化设计和运行提供依据。     

Form-stable phase change materials for thermal energy storage

The present paper considers the state of investigations and developments in form-stable phase change materials for thermal energy storage. Paraffins, fatty acids and their blends, polyethylene glycol are widely used as latent heat storage component in developing form-stable materials while high-density polyethylene (HDPE), styrene-butadiene-styrene (SBS) triblock copolymer, Eudragit S, Eudragit E, poly (vynil chloride) (PVC), poly (vynil alcohol) (PVA) and polyurethane block copolymer serve as structure supporting component. A set of organic and metallo-organic materials with high transition heat in solid-solid state is considered as perspective for-stable materials to store thermal energy. Another perspective class of form-stable materials are the materials on the basis of such porous materials as expanded perlite and vermiculite impregnated with phase change heat storage materials. The technology of producing new form-stable ultrafine heat storage fibers is developed. It opens availability to produce the clothers with improved heat storage ability for extremely cold regions. The perspective fields of application of form-stable materials are discussed. The further directions of investigations and developments are considered.     

含水层储能技术的应用及储能条件的分析

能源问题已经成为制约现代社会发展的重要问题,地下含水层储能为现代城市能源的短缺以及环境的保护提供了一个很好的解决途径,同时可以减少废气(CO2、SO2等)的排放。介绍了地下水储能的基本原理、意义、在空调领域的应用及其实现的条件。     

Architectural and urban design potentials for residential building energy saving in the Gulf region

Systematic computer simulations and energy performance studies are conducted for a typical residential building and prevalent conditions in the Gulf region. The studies systematically deal with variations of the main geometrical parameters of the building envelope, comprising plan proportion, orientation, glazing allocation and obstruction. Comparative evaluations and sensitivity analyses expose the effects of these variables and define their relative contributions to prime energy-performance indicators. The combined effectiveness and potentials of the parameters compensate for their limited individual contributions to warrant their practical consideration for passive architectural and urban design application.