最新刊期
      卷 24 ， 期 4 ， 2003
      • Vol. 24, Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.001
        摘要：In the heat pump heating system, the theoretical cycle analysis and a drop in experimental investigation on the performance of new fluid R417a as substitute of R22 were carried out. The results show that heating output of R417a is slightly less, but its power consumption decreases by about 10.58%, and COP is higher than that of R22. The discharge temperature of R417a is lower than that of R22. The system With R417a operates in a normal way and its lubricant doesn't need to change.  
          
        2208
        |
        414
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 71524657 false
        更新时间：2025-02-26

      • Development and Experimental Research on CO2 Transcritical Expander

        Vol. 24, Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.002
        摘要：As a natural working fluid, CO 2 is receiving more and more attention in the refrigeration. The key technology of the research of CO 2 transcritcia cycle is to improve the coefficient of performance of the system that is competitive with present conventional high performance refrigerant systems. In order to lower the throttling losses in the CO 2 transcritical cycle, the significant measure is to replace the throttling valve by an expander. This paper presents the development of the rolling piston expander and the activity items in the expander design, including the seal technology, the contact friction control and suction design. The experiments of the CO 2 expander conducted in our CO 2 transcritical cycle rig are described. The results show that the power output of the expander is related to the loads of the generator. The measured efficiency of this prototype is up to 32% and the further improvement of the expander is required.  
          
        1693
        |
        359
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 66525193 false
        更新时间：2025-02-26
      • Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.003
        摘要：The capacity of the refrigeration system could be increased by using the economizer, but the COP would not be improved equally due to the increased compressor power consumption from super feeding, and the improvement of COP depends mainly upon the parameters such as superfeed pressure, superfeed port location. In this study, the thermodynamic processes of the twin-screw refrigeration compressor at different superfeed pressures were investigated by analyzing the indication diagrams recorded in the twin-screw refrigeration compressor with an economizer, and the influence of the super-feed pressure on the compressor efficiency and system COP was obtained. The results show that the gas pressure in working chamber experiences a rapid increase as super-feed gas enters the chamber, and then a slow rise, and finally the pressure has a slight drop at the late phase of the super-feeding process. Correspondingly, the compressor efficiency and COP rise first and then drop, depending upon the superfeed pressure. As a result, there is an optimum superfeed pressure under which the system COP reaches the best.  
          
        1587
        |
        332
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 72828740 false
        更新时间：2025-02-26

      • Theoretical Research on A New Type Rotary Compressor

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.004
          
        1675
        |
        356
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 66524007 false
        更新时间：2025-02-26
      • Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.005
        摘要：This paper summaries the heat transfer and pressure drop correlations of different fin surfaces, and the corresponding influencing factors. The evaluation criteria of enhanced surface performances have also been described. The appropriate correlation and evaluation criterion will provide reliable foundation to the design and optimization of compact heat exchangers.  
          
        1740
        |
        379
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66524912 false
        更新时间：2025-02-26

      • Review on Heat Transfer of Subcritical Carbon Dioxide

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.006
        摘要：This paper gives a review of the heat transfer characteristics of subcritical carbon dioxide in-tube flow. Some published correlations for heat transfer coefficient during in-tube flow are collected. The accuracy of the correlations is discussed through comparing the calculation results with the experimental data. The applicable correlations in different conditions are recommended.  
          
        1756
        |
        351
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66524818 false
        更新时间：2025-02-26

      • Development of Ammonia-Salts Adsorption Working Pairs in Chemical Heat Pump

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.007
        摘要：Adsorption working pairs of ammonia-salts in chemical heat pump was analyzed and summarized. On the basis of the various heat sources, feasible adsorption working pairs were founded. The adsorption mechanism was analyzed and the application foreground of heat pump was discussed.  
          
        1686
        |
        364
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66524120 false
        更新时间：2025-02-26
      • Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.008
        摘要：The variable air volume (VAV) systems that use variable speed fans and the more recently developed control methods like the duct static pressure reset (DSPR) control are widely used in Hong Kong. The performance of the DSPR control and constant duct static pressure control method in an existing office building in Hong Kong was tested. The successful application of the control method requires proper matching between zone cooling loads and flow capacities of the supply fan and the VAV boxes, and adequate ductwork design.  
          
        1705
        |
        362
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66526472 false
        更新时间：2025-02-26

      • CFD Commercial Software and Air Conditioning & Refrigeration

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.009
        摘要：This paper introduces the general structure and characteristic of CFD commercial software. For the research and design work of air conditioning and refrigeration, the commonly used CFD commercial software is described with regard to the suitability, the grid characteristic, the numerical algorithm, the difference scheme, and the turbulence model. On the whole, each of the software has its own merit and suitability. The software must be analyzed and selected in application on the basis of the practical problem which is studied.  
          
        1636
        |
        332
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66524155 false
        更新时间：2025-02-26

      • New High Efficiency Refrigeration System for Large Scale Supermarket

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.010
        摘要：This paper describes a new high efficiency refrigeration system adopted in large scale supermarkets, in which parallel compressor unit is the core technique. Detailed comparison to the traditional system so called 'one compressor vs multiple end-units' is also performed. Being practically utilized in many large supermarket projects such as Walmart, Auchan , and Carrefour, this refrigeration system is confirmed to be more safe and reliable, and temperature control of showcase and cold storage room is more stable. Moreover, the system energy is significantly saved by 18% and original investment cost is saved by 20%.  
          
        1717
        |
        349
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66525562 false
        更新时间：2025-02-26

      • Parametric study on fresh-keeping technology of chestnut in low temperature

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.011
          
        1702
        |
        361
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66526410 false
        更新时间：2025-02-26

      • Application Study of Economic Residential Air Conditioning System

        Issue 4, (2003) DOI: 10.3969/j.issn.0253-4339.2003.04.012
        摘要：On the basis of the current energy and electricity's usage in our country, a new residential air conditioning system-the refrigeration potential energy storage system with economy and environmental protection is presented. The economic analysis, advantages and other properties of this system are described. This refrigeration system with potential energy storage has a very good development prospect.  
          
        1735
        |
        354
        |
        0
        <HTML>
        <DownloadPDF><Meta-XML>
        <引用本文> <批量引用> 66524071 false
        更新时间：2025-02-26
      0