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《上海节能》2017,(1)
介绍了云南普洱市的某茶业公司PCM空气式太阳能一热泵联合干燥房建设及应用实例。普洱茶传统加工工艺采用燃煤蒸汽锅炉进行茶饼烘干处理,现进行技术改造,采用节能环保的PCM空气式太阳能热泵干燥系统代替现有的燃煤锅炉干燥系统。通过PCM空气式太阳能集热系统,将太阳能转换热能。以空气为换热介质与空气式太阳能集热器进行换热,通过循环风机直接将热风通入到烘房内提供物料干燥热量需求;当太阳能不足时,启动空气源热泵系统。对该工程的设计方案并及干燥系统工作原理进行了详细介绍,从干燥系统运行过程中采集数据进行分析计算,计算结果表明本干燥系统节能效果明显。这些数据对目前高效利用太阳能进行商业干燥设计参数的选取,以及太阳能干燥系统的优化设计具有重要借鉴意义。 相似文献
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为缩短枸杞干燥时间,提高干制枸杞的质量,减少能源消耗,本文提出了一种新型太阳能–空气源热泵联合干燥系统。该系统主要由太阳能集热器和空气源热泵机组等设备组成,可以实现太阳能单独干燥、热泵单独干燥和太阳能–空气源热泵联合干燥三种工作模式。本文根据枸杞的干燥特性,分段设定最佳的干燥温度,进行了热泵单独运行和太阳能–热泵联合运行两种工作模式下干燥枸杞的对比实验。结果表明,干燥50 kg枸杞,太阳能–热泵联合运行比热泵单独运行节省了2.9 kW?h电能,若同时除去系统本身的耗能,节省的电能占热泵单独运行耗电量的29.5%。同时,与太阳能单独干燥相比,太阳能–热泵联合干燥具有较高的除湿能耗比,两者最大差值为0.71 kg/(kW?h)。本文提出的太阳能–热泵联合干燥系统具有提高干燥产品的品质、缩短干燥时间和节约干燥成本等优点,适宜推广。 相似文献
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本文受到太阳能烟囱发电技术的启发,提出用直接空冷火电站乏汽放出的潜热替代太阳能烟囱发电中不稳定的太阳能,不仅弥补了太阳能烟囱发电技术的不足,而且回收利用了直接空冷火电站中以往被浪费的乏汽潜热,进一步减少了火电站鼓风机的耗电量。以一台600 MW直接空冷火电机组为例,对系统的热力过程、阻力进行了理论分析。计算结果表明该系统每年可以回收电能2.89×108kW/h,可以产生约1.08亿元的经济效益;相当于每年可以节省标准煤10.43万t,减少排放CO2约27.32万t、SO2约886 t、NOx约772 t,经济效益和节能减排效果显著。 相似文献
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蜜枣太阳能对流干燥最佳工况的试验研究 总被引:2,自引:0,他引:2
以蜜枣为干燥对象进行了太阳能对流干燥试验,建立了干燥数学模型;以能耗为优化目标得到了蜜枣太阳能对流干燥的最佳工况,并与蜜枣纯对流干燥的能耗进行了对比,对比结果表明太阳能对流干燥比纯对流干燥有明显的节能效果。 相似文献
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为解决工农业干燥过程中存在的干燥效率低、能耗高等问题,同时充分利用生产过程中产生的中低品位热能,设计了一种可控温湿度的中低温热源干燥系统,干燥系统由加热系统、排湿换气系统、温湿度控制系统和干燥室组成。介绍了其干燥工艺,分析了其运行性能和能耗情况,通过试验数据分析发现该干燥系统气流温度和速度分布均匀、能耗低,系统在整个干燥过程中的干燥速率为0.122 kg/(kg∙h),整个过程的能耗因子为391.2 kJ/kg。系统适用于以地热能和工业余热等中低温热能为热源的工农业干燥过程。 相似文献
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In this work a thermal performance analysis of the solar drying process is presented. It describes semi-empirical models for the thermal characterization of an experimental indirect solar dryer device. A procedure for designing drying equipment, which takes into account the varying operating conditions given by the variations of the environmental conditions is also presented. On the other hand, a simplified method to design solar collectors based on the determination of minimum entropy generation during the thermal conversion of solar energy, is described. Finally, the results of the preliminary design of the solar dryer are presented using the thermal analysis procedure and the method derived from the Second law of thermodynamics. 相似文献
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Haifeng Li Yanjun Dai Jianguo Dai Xibo Wang Lei Wei 《Frontiers of Energy and Power Engineering in China》2010,4(3):386-391
For grain in-store drying, a solar assisted drying process has been developed, which consists of a set including a solar-assisted
heat pump, a ventilation system, a grain stirrer, etc. In this way, low power consumption, short cycle time and water content
uniformity can be achieved in comparison with the conventional method. A solar-assisted heat pump drying system has been designed
and manufactured for a practical granary, and the energy consumption performance of the unit is analyzed. The analysis result
shows that the solar fraction of the unit is higher than 20%, the coefficient of performance about system (COPS) is 5.19,
and the specific moisture extraction rate (SMER) can reach 3.05 kg/kWh. 相似文献
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For grain in-store drying, a solar assisted drying process has been developed, which consists of a set including a solar-assisted heat pump, a ventilation system, a grain stirrer, etc. In this way, low power consumption, short cycle time and water content uniformity can be achieved in comparison with the conventional method. A solar-assisted heat pump drying system has been designed and manufactured for a practical granary, and the energy consumption performance of the unit is analyzed. The analysis result shows that the solar fraction of the unit is higher than 20%, the coefficient of performance about system (COPS) is 5.19, and the specific moisture extraction rate (SMER) can reach 3.05 kg/kWh. 相似文献
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This paper is the first of two papers that describe the modeling, design, and performance assessment based on monitored data of a building-integrated photovoltaic-thermal (BIPV/T) system thermally coupled with a ventilated concrete slab (VCS) in a prefabricated, two-storey detached, low energy solar house. This house, with a design goal of near net-zero annual energy consumption, was constructed in 2007 in Eastman, Québec, Canada - a cold climate area. Several novel solar technologies are integrated into the house and with passive solar design to reach this goal. An air-based open-loop BIPV/T system produces electricity and collects heat simultaneously. Building-integrated thermal mass is utilized both in passive and active forms. Distributed thermal mass in the direct gain area and relatively large south facing triple-glazed windows (about 9% of floor area) are employed to collect and store passive solar gains. An active thermal energy storage system (TES) stores part of the collected thermal energy from the BIPV/T system, thus reducing the energy consumption of the house ground source heat pump heating system. This paper focuses on the BIPV/T system and the integrated energy concept of the house. Monitored data indicate that the BIPV/T system has a typical efficiency of about 20% for thermal energy collection, and the annual space heating energy consumption of the house is about 5% of the national average. A thermal model of the BIPV/T system suitable for preliminary design and control of the airflow is developed and verified with monitored data. 相似文献
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This paper presents the potential benefits of the thermal load sharing between the two different building types such as residential house and commercial office building through the process of energy simulation modeling. Both the house and office simulation models have the same geometries with the conditioned spaces of 200 m2 each for the weather conditions of Seoul, South Korea. This study shows and analyzes the thermal energy demand and consumption results simulated from the four different scenarios using the EnergyPlus V6.0 thermal simulation program; i.e., Case-1) a house with conventional heating and cooling systems, Case-2) an office with conventional heating and cooling systems, and Case-3) a simple sum of the two cases (i.g., Case-2 + Case-3), and Case-4) a load sharing model that provides heating and cooling to both the house and the office using combined HVAC systems. This paper evaluates the thermal energy consumption patterns and potential benefits of the load sharing system compared to the conventional systems. The optimal system configurations of the load sharing systems are proposed. In conclusion, this paper discusses the potential issues and challenges for implementing the load sharing systems as well as the possible solutions for these issues. 相似文献
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《International Journal of Hydrogen Energy》2021,46(74):36678-36686
In the study, the effects of hydrogen mixing studies at the rate of 20% to the natural gas system which is an ongoing study in Turkey, on the photovoltaic system (PV) is investigated using a real house consumption. Providing the annual electrical energy consumption (1936,83 kWh) and 20% of natural gas consumption (62,4 m3) of a real house with hydrogen is included in the study. A PV-hydrogen system is theoretically investigated to provide the energy required for hydrogen production from solar panels. Hydrogen blending effects on PV size, capacity usage, and carbon footprint are analyzed. Thus, the contribution was also made to the “green hydrogen” works and reduction of the carbon footprint of the house. It was found that the required hydrogen for electricity can be provided 52,5 m2 solar panel area and 14,28% increase in this area and installed power can provide an amount of hydrogen that need for 20% hydrogen blending to the natural gas system. The overall system capacity usage decreased when the system is used for 20% hydrogen blending to the natural gas system. The carbon footprint of the house was decreased by 67,5%. If the hydrogen has not been blended with 20% natural gas, this ratio would have been 59,2%. 相似文献
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Humidity and indoor moist surrounding affect air cleanliness and protects harmful microorganisms when relative humidity is above 70%. In humid climates, the humidity issues are a major contributor to energy inefficiency in HVAC devices. The use of liquid desiccant dehumidification systems of supply air is a viable alternative to reduce the latent heat load on the HVAC system and improve efficiency. Thermal energy, at a temperature as low as 40–50°C, required for the operation of a liquid desiccant hybrid air conditioner can be efficiently obtained using a flat-plate solar collector. In this work a model of a solar-operated liquid desiccant system (using calcium Chloride) for air dehumidification is developed. The system utilizes packed beds of counter flow between an air stream and a solution of liquid desiccant for air dehumidification and solution regeneration. The desiccant system model is integrated with a solar heat source for performance evaluation at a wide range of recorded ambient conditions for Beirut city. Standard mass and energy balances are performed on the various components of the system and a computer simulation program is developed for the integrated system analysis. The desiccant system of the current study replaces a 3 TR (10.56 kW) vapour compression unit for a typical house as low latent load application, and is part of a hybrid desiccant–vapour compression system for a high latent load application, namely a small restaurant with an estimated cooling load of 11.39 TR (40 kW), including reheat. The relevant parameters of the desiccant system are optimized at peak load, and it is found out that there is an important energy saving if the ratio of the air flow rate in the regenerator to that in the dehumidifier is about 0.3 to 0.4. The COP of the desiccant unit is 0.41 for the house, and 0.45 for the restaurant. The size of the vapor compression unit of the restaurant is reduced to 8 TR when supplemented by a desiccant system. The performance is studied of the desiccant system integrated with a solar collector system and an auxiliary natural gas heater to heat the regenerator. The transient simulation of the solar desiccant system is performed for the entire cooling season. The solar fraction for the house is equal to 0.25, 0.47, and 0.68 for a collector area of 28.72, 57.44, and 86.16 m2, respectively. The solar fraction for the restaurant is 0.19, 0.38, and 0.54, for the same collector areas. The life cycle savings for the house run solely on desiccant system were positive only if natural gas is available at a cheap price. For the restaurant, the economic benefit of the desiccant system is positive, because the need for reheat in the vapor compression system is eliminated. For a gas price of 0.5638 $/kg, the payback period for the restaurant turned out to be immediate if the energy is supplied solely by natural gas, and 11 years if an 86.16 m2 solar collector is implemented to reduce the fuel consumption. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献