不同岩土热物性参数测试方法的比对试验研究

岩土热物性参数以及如何准确获得岩土体热物性参数的方法对整个地埋管地源热泵系统的设计至关重要。本文通过对一个实际应用的地源热泵系统的研究,采用两种测试方法进行测试分析对比;使用瞬时系统模拟软件TRNSYS建立理论分析模型,基于不同的热物性参数测试方法对地源热泵系统设计进行分析,指出两种测试方法的偏差和优缺点,为地埋管地源热泵工程设计及施工提供依据。     

Performance of solar water heaters with narrow mantle heat exchangers

This paper evaluates the performance of narrow-gap vertical mantle heat exchangers with a two-pass arrangement for use in pumped-circulation solar water heaters. Both measured mantle side and tank side heat transfer correlations have been developed and implemented in a TRNSYS model of a complete solar water heater incorporating this type of heat exchanger. Predictions of the annual solar contribution for mantle-tank systems are compared to direct-coupled systems. The direct-coupled systems are found to provide slightly higher annual energy saving than mantle-tank systems for standard domestic hot water demand in Australia. However, the reduction in performance is outweighed by the benefit of freeze protection provided by incorporating a collector loop heat exchanger in the system.     

Techno-economic appraisal of a dish/stirling solar power plant in Greece based on an innovative solar concentrator formed by elastic film

As the environmental problems caused by the use of conventional fuels have risen significantly and due to the increase in fossil fuel prices, the importance of reducing society dependence on non-renewable energy sources becomes more and more urgent. It is clear that this could only happen by switching to extensive use of clean energy sources such as renewable energy sources. In this paper a technical feasibility and economic viability study of a dish/Stirling solar power plant in Greece is presented. The proposed power plant uses Dish/Stirling technology and has nominal power 10 MW. The proposed solar concentrator system consists of a primary mirror, formed by elastic film, used to focus the sun's rays onto a secondary mirror which then deviates this radiation into the receiver (Stirling engine). TRNSYS program was developed to simulate Dish/Stirling power plant operation in order to investigate its performance in Greece. The simulation predicted that the proposed power plant could produce 11.19 GWh annually. Project investment cost is approximately 27,000,000 €, while payback is achieved after 16 years of operation. The total profit at the end of the analysis period of 25 years is estimated to be 25,500,000 €.     

Optimum design criteria for solar hot water systems

This paper is concerned with the optimisation of some design criteria of SHW systems intended for residential and hotel applications. For this purpose, a system model based on TRNSYS programme has been used to correlate the performance and cost effectiveness of the system with a number of key design criteria which include the Collector to Consumer Factor (FCC) expressed in m² of collector per consumer and the Collector to Load Factor (FCL) expressed in m² of collector per annual GJ of thermal load.     

严寒地区地源热泵系统关键设计参数研究

由于严寒地区土壤源热泵取热和放热不均,土壤温度逐年下降,需要针对寒区运行情况制定补热方案。本文以严寒地区某典型建筑为例,基于TRNSYS对地源热泵系统运行特性进行仿真研究,分析地源热泵系统关键设计参数对系统运行特性的影响,其结论为严寒地区地源热泵系统设计参数选取及辅助热源补热策略提供参考。     

Investigation on the feasibility and performance of ground source heat pump (GSHP) in three cities in cold climate zone,China

As a renewable energy technology, ground source heat pump (GSHP) system is high efficient for heating and cooling in office buildings. However, this technology has strong dependence on the meteorological and building envelope thermal characteristic parameters. For the purpose of quantitative investigation on the feasibility and performance GSHP, three cities located in cold climate zone, Qiqihaer, Shenyang and Beijing, were sampled. Firstly, the office building dynamic loadings in these cities were calculated on basis of the different meteorological and envelope thermal characteristic parameters. The TRNSYS, one kind of energy simulation software, were employed to simulate the operation performances of GSHP on basis of these parameters. The simulation revealed the data on the outlet/inlet temperature of buried pipes, soil temperature, energy consumption distribution and the coefficient of performance (COP) for one year operation. Furthermore, ten years operation was also simulated to show the stability of the performance based on the outlet/inlet temperature of buried pipes and soil temperature. From these results, the GSHP had shown its most suitable performance in Beijing, second in Shenyang and worst in Qiqihaer. These results could be used as a reference on suitable utilization of GSHP systems in office buildings located in cold climate zone, China.     

The application of heat pipe heat exchangers to improve the air quality and reduce the energy consumption of the air conditioning system in a hospital ward—A full year model simulation

Research was conducted to study the effect of heat pipe heat exchangers on the existing air conditioning system of a hospital ward located in Malaysia, a tropical region. The present research employs the transient system simulation software (TRNSYS) to study the hour-by-hour performance of the system in terms of supply duct air and indoor air conditions in the ward space. Fieldwork study showed that the existing air conditioning system operating in the Orthopaedic Ward, University of Malaya, Malaysia is not capable of providing the desired supply duct air and indoor air to the space. Therefore, the possibility of improving the air conditioning system by adding heat pipe heat exchangers was investigated. The impact on energy consumption, power savings, supply duct air and indoor air with heat pipe heat exchangers incorporated in the air conditioning system were simulated and the results were compared with the existing system.Based on the present research, the system with the added eight-row heat pipe heat exchangers is recommended to provide convenient and healthy air into the ward space according to the ASHRAE recommendations. Moreover, it was found that by applying the new design, a considerable amount of energy and power could be saved.     

Comparison of annual energy performances with different ventilation methods for cooling

Stratum ventilation has been proposed to cope for elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following three factors: the reduction in ventilation and transmission loads and increased COP of chillers. The year-round energy saving is found to be substantial at 25% and 44% at least when compared with displacement ventilation and mixing ventilation, respectively.     

The dynamic modeling and the exergy assessment of hydrogen synthesize and storage system with the power-to-gas concept for various locations

In this article, the solar hydrogen storage is modeled and hourly investigated with TRNSYS software. The Photovoltaic (PV) panel is employed for green power generation that is consumed in the electrolyzer subsystem and produced hydrogen. Additionally, the required electricity at the lack of enough solar irradiation is supplied from the grid. The performance of the system is comparatively analyzed for three main cities. Results show that the maximum power generation by PV panel is about 1670 kW in June which approximately is the same for two cities. The energy and Faraday efficiency of electrolyzer changes between 0.85-0.89 and 0.89–0.92 respectively. The amount of hydrogen production reaches 1235 m³/h for one of them in May. The total amount of hydrogen production is 13,181 m³/year in Yazd, 13,143 m³/year in hot city, and 13,141 m³/year in most populated city.     

Experimental results and simulation with TRNSYS of a 7.2 kWp grid-connected photovoltaic system

This paper presents a dynamic model and experimental results of a 7.2 kWp photovoltaic (PV) installation located at the Polytechnic University of Valencia (Spain). The modelling of the monocrystalline cells has been realised in TRNSYS and has been validated during an extensive experimental campaign from January 2001 to March 2003, using the data of a fully monitored PV field. The simulation results with TRNSYS provide an accurate prediction of the long-term performance. In addition to the dynamic models, algebraic methods such as the constant fill factor have also been applied.