An experimental study on variable air volume operation of ducted air-conditioning with digital scroll compressor and conventional scroll compressor

https://doi.org/10.1016/j.applthermaleng.2007.06.018Get rights and content

Abstract

An experimental study on operation characteristics with variable air volume under refrigerating and heating condition of ducted air-conditioning (AC) unit with digital scroll compressor and conventional scroll compressor is conducted in this paper. The effects of air volume on the refrigerating (heating) capacity, input power, EER (COP), outlet temperature, discharge pressure, discharge temperature and suction pressure are studied. Compared with the ducted air-conditioning unit with conventional scroll compressor, the experimental results are the outlet temperature of ducted AC unit with digital scroll compressor is stable; the suction pressure and discharge pressure are normal; the discharge temperature drops a bit; the input power is lower. This shows that the unit with digital scroll compressor is well adapted to the variable air volume running and good for the economical and reliable operation of the ducted AC unit.

Introduction

Household central air-conditioning mainly includes household multi-connected air-conditioning, mini-type air-source heat pump/chiller with fan coil unit, ducted air-conditioning (heat pump) unit and so on. Ducted AC (heat pump) unit is characterized of high efficiency, convenient installation, supply of fresh air, less initial investment, etc. It has been widely used in restaurant, supermarket and factory workshop. Ducted AC units mostly adopt constant speed compressor and operate with constant air volume currently, but users often need to adjust the air supply, which requires that the unit operation performance is suitable for the variable air volume. It should be made sure that the unit is operating with high efficiency and reliable status when the main characteristics such as discharge temperature, discharge pressure, suction pressure, and outlet air temperature change in a certain range. AC unit with digital scroll compressor is one which running at variable air volume in high efficiency. So this type of unit has been paid more attention by scientists and engineers. The application of digital scroll compressor in multi-type air conditioning system was introduced by Hu and Yang [1]. Jiang et al. [2] discussed the control of digital compressor applied in multi-type air conditioning system. Kan et al. [3] analyzed the application of digital scroll compressor in cold storage container. Zhou and Zhang [4] studied the energy saving of digital scroll compressor. Qiu and Qiu [5] discussed the application of digital scroll compressor in high accuracy constant temperature and humidity air conditioning. The application of heat pump with digital scroll compressor under low ambient was addressed by He et al. [6]. Analysis and comparison between digital scroll and inverter technology was performed by Shi and Ma et al. [7], [8]. Ye and Chen [9] analyzed the energy saving factors of digital scroll compressor in VRV air-conditioning system. Wu and Wu [10] discussed the problem about how to make digital scroll compressor matching the heat load of a building air conditioning. Up to now, seldom researches have been conducted on variable air volume operation characteristics of ducted AC unit. There is also seldom comparative study on the application of air-conditioning system with digital scroll compressor and conventional scroll compressor. In order to study the operation characteristics, an experimental study on the variable air volume of ducted AC units with digital scroll compressor and conventional scroll compressor is performed under refrigerating and heating condition in this paper. The effects of air volume on refrigerating (heating) capacity, input power, EER (COP), outlet temperature, discharge pressure, discharge temperature and suction pressure will be analyzed. The characteristic of ducted AC unit with digital scroll compressor will be also compared with that of ducted air-conditioning unit with conventional scroll compressor.

Section snippets

Experimental system

The experimental system on variable air volume operation of ducted air-conditioning unit with digital scroll compressor and conventional scroll compressor is shown in Fig. 1. It is certificated by the National Quality Supervision and Inspection Center for Compressor and Refrigeration Equipment Products. As shown, the system consists of outdoor environment room, indoor environment room, units supporting the environment and measuring equipments. The dry-bulb temperature control range of the

Experimental procedure and results analysis

The experimental study on performance characteristics of variable air volume between ducted AC unit with digital scroll compressor and the unit with conventional scroll compressor under the refrigerating and heating condition is performed. In refrigerating running experiments, inlet air dry-bulb temperature and wet-bulb temperature of indoor side are 27 °C and 19 °C, respectively, inlet air dry-bulb temperature and inlet air wet-bulb temperature of outdoor side to be 35 °C and 24 °C, respectively.

Conclusions

The comparative experimental study on operation characteristics with variable air volume under refrigerating and heating condition of ducted air-conditioning (heat pump) unit with digital scroll compressor and the unit with conventional scroll compressor is performed. For a unit with conventional scroll compressor, when air volume decreases, its energy output changes passively in a narrow scope. From the effects of air volume on the unit capacity, efficiency, outlet temperature, especially

Acknowledgements

We are grateful to Nanjing TICA Air-conditioning Co., Ltd. for providing the sampling unit, and we acknowledge Professor Zhenqian Chen for kindly giving revising suggestions.

References (11)

  • S.C. Hu et al.

    Development and testing of a multi-type air conditioner without using AC inverters

    Energ. Conver. Manage.

    (2005)
  • Y.T. Jiang et al.

    Application and discussion of the digital scroll technology in VRV air-conditioning system

    Refrigeration

    (2006)
  • A.K. Kan et al.

    The application of cold storage container with digital scroll compressor

    Compres. Technol.

    (2005)
  • G.Z. Zhou et al.

    The characteristic of air conditioning system with digital scroll

    Energ. Res. Utiliz.

    (2005)
  • Y.Q. Qiu et al.

    Research and development and the experiment confirmation of high accuracy constant temperature and humidity air conditioning

    Refrig. Air-condition.

    (2006)
There are more references available in the full text version of this article.

Cited by (22)

  • Effect of refrigerant flow direction and throttle opening in RAC unit using micro-channel evaporator

    2016, International Journal of Refrigeration
    Citation Excerpt :

    The experiments are conducted by means of air enthalpy difference method in an enthalpy different laboratory. The measurement range and accuracy of the enthalpy difference laboratory instrumentation meet the requirements in Chinese national standard (Huang et al., 2008; Zhongbin et al., 2014). The first section of the experiments is operated to compare the performances of the sample unit adopting UF mode and DF mode in the micro-channel evaporator.

  • Study on simplified evaluation method for annual operation performance of multi-connected air conditioning system

    2016, Applied Thermal Engineering
    Citation Excerpt :

    There have been several studies dealing with multi-connected air conditioning system in literature. Four main subjects are focused on by researchers, (a) operating characteristics [2–8], (b) energy saving possibility [9–11], (c) control strategies [12–17], (d) standards for multi-connected air condition unit [18–23]. Zhao [2] and Meng [3] addressed experimental study on performance of VRF air conditioning system under part load conditions.

  • Study on energy saving possibility of digital variable multiple air conditioning system in three office buildings in Shanghai

    2014, Energy and Buildings
    Citation Excerpt :

    Zhang [2,3] and Zhao [4] addressed experimental study on performance of digital variable multiple air conditioning system under part load conditions. Huang [5] conducted an experimental study on operating characteristics of ducted air conditioning unit with digital scroll compressor and conventional scroll compressor under refrigerating and heating condition. Hu and Yang [6] discussed the relationship between the opening degree of electronic expansion valves and the compressor output ratio.

View all citing articles on Scopus
View full text