Energy and temperature performance analysis of geothermal (ground source) heat pumps integrated with permeable pavement systems for urban run-off reuse

Geothermal (ground source) heat pumps (GHP) and permeable pavement systems (PPS) have demonstrated their effectiveness in both industry and academic research during recent decades. To meet the rising demand for sustainable, recyclable and energy efficient techniques, research has focused on the combination of techniques to enhance existing or develop new applications.

This paper reports on an experimental programme that combined GHP with PPS for nutrient removal and system energy balancing. Experimental data collected over a 3-year period have provided evidence of highly efficient removal rates of up to 99% for ammonia–nitrate and biochemical oxygen demand; and 96% removal rates were obtained for orthophosphate–phosphorus. This paper also contains energy efficiency ratio (EER) and coefficient of performance (COP) calculations. Cyclic heat removal and heat rejection allowed for stable temperature and pump COP and EER sustainability. The results prove that PPS systems are appropriate for GHP installation, delivering high and stable pollutant removal with EER efficiencies between 1.5 and 5.5.

The combination of GHP with PPS has the potential to provide a new sustainable and eco-friendly practice.     

Performance analysis of a new sustainable evaporative cooling pad made from coconut coir

This paper reports a performance analysis for a new sustainable engineering application to beneficially reuse an abundant agricultural waste, coconut coir (Cocos nucifera), in evaporative cooling pads. Two small coconut coir pads of different configurations were fabricated and tested using a laboratory‐scale experimental arrangement. The air supply velocity was controlled and varied between 1.88 and 2.79 m s^?1. Heat and mass transfer coefficients, evaporative cooling efficiency and pressure drop across the two types of coconut coir pad were analysed and compared with those of a commercial rigid media paper pad. Results show that the cooling efficiency of the manufactured coconut coir evaporative cooling pad was fairly good (about 50%) and close to that of the commercial paper pad (about 47%). The average pressure drop across the two coconut coir pads was 1.5 and 5.1 Pa respectively. Correlations for heat and mass transfer coefficients expressed using Nusselt and Sherwood numbers are also reported. In addition, the cooling potential of the coconut coir pads was analysed using the average climatic conditions of the central region in Thailand throughout the year. The analysis showed that the air temperature leaving the coconut coir pad varied from 23 to 28°C. Commercial development appears feasible given the coconut coir pad's good performance, lower cost and its availability throughout the country.     

Harvesting heat energy from asphalt pavements: development of and comparison between numerical models and experiment

The use of flowing water in embedded pipes to harvest heat energy from asphalt pavements and thereby reducing its temperature and the urban heat island effect has been proposed. A successful use of such an approach would require a complete understanding of the effect and the interaction of various mechanisms such as conduction, convection and radiation and factors such as solar radiation, diameter of pipe and rate of flow. A large-scale experiment was conducted to understand such effects, and numerical modelling was conducted for prediction of temperature. The experiment was modelled using finite element method, and a good match was obtained between predicted and experimentally obtained results. Effects of pipe diameter and flow rate were also analysed. This model could be used in future for selection of appropriate levels of critical variables and hence successful implementation of this concept to sustainable pavements.     

Combustion,performance and emissions of a DI-CI engine running on Karanj methyl ester: influence of injection timing

This study aims at evaluation of the effect of injection timing on the combustion, performance and emissions of a small power diesel engine, commonly used for agriculture purpose, running on pure bio-diesel, prepared from Karanj (Pongamia pinnata) vegetable oil. The effect of varying injection timing was evaluated in terms of thermal efficiency, specific fuel consumption, power and mean effective pressure, exhaust temperature, cylinder pressure, rate of pressure rise and the heat release rate. Furthermore, the effects on emissions of unburnt hydrocarbons, oxides of nitrogen, carbon monoxide and carbon dioxide and smoke were also studied. It was found that retarding the injection timing by 3° enhances the thermal efficiency by about 8.2% with reduction in emission of oxides of nitrogen.     

丙烯腈装置尾气废液焚烧及余热回收技术

介绍了丙烯腈装置尾气、废液焚烧及余热回收技术，分析了其工艺技术特点，从环保角度对其技术进行了探讨。     

基于定量遥感技术的重庆市热岛效应

近年来，城市热岛效应不断增强，已经成为一个突出的城市环境问题。重庆市作为长江中上游特大型城市，工业发达，经济快速发展，市区热岛效应明显，但是很少对其研究。以2007年Landsat5 TM影像为数据源，利用单窗算法对重庆市城市地表温度进行反演，并进行城市地面亮温等级划分，在从城市土地利用类型、NDVI等方面对重庆市城市热岛效应强度和空间格局分布及其特征进行了探讨。结果表明：城区热岛现象显著，且分布不均匀；不同土地利用类型对热岛效应影响不同；城市地面亮温与NDVI呈明显的线性负相关关系。最后结合重庆市的特殊地形，提出了以下解决城市热岛效应的对策：加强城市规划，调整城市结构；构建最佳绿化结构，提高城市绿化率；改变能源结构，提高能源利用率，控制工厂废气排放量。     

煤矿井筒防冻的无风机方式及耗热量计算

防止煤矿井筒出现结冰现象，对保证矿井安全生产和正常生产至关重要。无风机方式有别于其他传统的方式，是一种技术可靠、造价低、非常适合于我国广大地区的井筒防冻方式。     

Critical Loads – Is There A Need For A New Concept?

The concept of critical loads has been an important andsuccessful tool for the development of control strategiesfor transboundary air pollution in Europe. The use of theconcept has led us to a situation where very few areas inEurope will have an exceedance of critical loads foracidification in 2010, indicating that the benefits offurther control acidifying substances will be lessuseful. The critical loads concept does not, however,take into account the large benefits of further controlin damaged systems but where critical loads are nolonger exceeded. In this paper we discuss the importanceof widening the critical loads concept to include thesebenefits and we propose an additional effect-relatedmeasure, Dynamic Impact Analysis, to be included infurther control strategies and assessments. With such aconcept the actual situation and its further developmentwill be included in assessments and control strategies.     

基于遥感技术的城市污水处理厂热岛效应研究

热岛效应已成为城市化发展中影响局地气候变化的重要因素之一.作为城市必要基础设施的一部分,城市污水处理厂对全球性气候变化的影响受到了广泛关注和研究,而对局地气候变化的影响却鲜有研究.文章首次尝试利用Landsat卫星遥感图像对1995年-2013年间苏州市11座城市污水处理厂进行了热岛效应研究,并对影响因素进行了初步分析.结果发现,11座城市污水处理厂热岛强度在18年间整体上增加了48％;从时间维度上来看,在污水处理厂施工建设或升级改造阶段,热岛强度都偏高.而根据回归分析发现,城市地表平均温度、污水处理厂的施工建设状态和主体处理工艺与WHII具有显著正相关性.     

风速及风向对城市热岛强度的影响研究

为研究气象参数风对城市热岛效应影响,利用2008—2013年长沙气象局提供的相关气象数据,采用统计方法,首次研究了风速和风向对热岛强度分布规律的影响。结果表明:长沙热岛效应主要发生在晚间;热岛强度值随风速的增大而降低;处于顺风方向上的南北方向,两者热岛强度的差值随风速的增大而逐渐减少;处于与风向垂直方向上的东西方向,两者热岛强度的差值不受风速大小的影响。气象参数风对城市热岛强度和空间分布影响显著。