Characteristics of air-cooled package air conditioners with refrigeration pump for data centers

Yuji Kohata, Yosuke Udagawa, Keisuke Sekiguchi, Masahide Yanagi, Kiyoshi Saito, Keisuke Ohno, Yasuhiro Naito, Tsuneo Uekusa

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    1 Citation (Scopus)

    Abstract

    In recent years, the amount of energy consumed by data centers has tended to increase. Therefore, power savings are strongly suggested. Data centers must be cooled year-round due to the extremely large amount of heat emitted from the IT devices. Therefore, to decrease year-round energy consumption, it is important to use low-temperature outdoor air during cool seasons such as mid-to-late fall and early spring and cold seasons like winter. Thus, we investigated cooling systems that use low-temperature outdoor air, and we developed a package air conditioner (A/C) that has cooling functions that use outdoor air. The new A/C combines a compression cycle and a cycle that stops the compressor and circulates coolant with a pump; it operates by switching to a compression cycle when the outdoor temperature is high and switching to a pump cycle when the outdoor temperature is low. Specifically, the pump cycle is the system of taking the low-temperature outdoor air into a coolant cycle from the heat exchanger in the outdoor unit (indirect outdoor-air cooling method) and transporting cold energy into the room with a pump. The A/C reduces the energy consumption in low outdoor temperatures by operating in favor of the efficient pump cycle. In this report, in order to verify the characteristics of the A/C, we built a simulation mathematical model. In addition, we verified the validity of the mathematical model compared to the measured value of the prototype. We show the effects of refrigerant circulation and outdoor-air temperature as an example of the verification simulation using a mathematical model. We calculated the annual energy consumption of the package A/Cs with refrigeration pumps based on the outdoor-air temperature data and the operating efficiency of the outdoor-air temperature. Specifically, the A/C that we developed reduced energy consumption by 50% in New York and 53% in Chicago, compared to the energy consumption of conventional computer-room A/Cs.

    Original languageEnglish
    Title of host publicationASHRAE Transactions
    PublisherAmer. Soc. Heating, Ref. Air-Conditoning Eng. Inc.
    Pages430-439
    Number of pages10
    Volume121
    ISBN (Print)9781936504961
    Publication statusPublished - 2015
    Event2015 ASHRAE Winter Conference - Chicago, United States
    Duration: 2015 Jan 242015 Jan 28

    Other

    Other2015 ASHRAE Winter Conference
    CountryUnited States
    CityChicago
    Period15/1/2415/1/28

    Fingerprint

    Refrigeration
    Pumps
    Air
    Energy utilization
    Temperature
    Mathematical models
    Coolants
    Cooling
    Refrigerants
    Cooling systems
    Heat exchangers
    Compressors
    Compaction

    ASJC Scopus subject areas

    • Mechanical Engineering
    • Building and Construction

    Cite this

    Kohata, Y., Udagawa, Y., Sekiguchi, K., Yanagi, M., Saito, K., Ohno, K., ... Uekusa, T. (2015). Characteristics of air-cooled package air conditioners with refrigeration pump for data centers. In ASHRAE Transactions (Vol. 121, pp. 430-439). Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc..

    Characteristics of air-cooled package air conditioners with refrigeration pump for data centers. / Kohata, Yuji; Udagawa, Yosuke; Sekiguchi, Keisuke; Yanagi, Masahide; Saito, Kiyoshi; Ohno, Keisuke; Naito, Yasuhiro; Uekusa, Tsuneo.

    ASHRAE Transactions. Vol. 121 Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc., 2015. p. 430-439.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Kohata, Y, Udagawa, Y, Sekiguchi, K, Yanagi, M, Saito, K, Ohno, K, Naito, Y & Uekusa, T 2015, Characteristics of air-cooled package air conditioners with refrigeration pump for data centers. in ASHRAE Transactions. vol. 121, Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc., pp. 430-439, 2015 ASHRAE Winter Conference, Chicago, United States, 15/1/24.
    Kohata Y, Udagawa Y, Sekiguchi K, Yanagi M, Saito K, Ohno K et al. Characteristics of air-cooled package air conditioners with refrigeration pump for data centers. In ASHRAE Transactions. Vol. 121. Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc. 2015. p. 430-439
    Kohata, Yuji ; Udagawa, Yosuke ; Sekiguchi, Keisuke ; Yanagi, Masahide ; Saito, Kiyoshi ; Ohno, Keisuke ; Naito, Yasuhiro ; Uekusa, Tsuneo. / Characteristics of air-cooled package air conditioners with refrigeration pump for data centers. ASHRAE Transactions. Vol. 121 Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc., 2015. pp. 430-439
    @inproceedings{a11b978f699341ea9d17c9af1909b11e,
    title = "Characteristics of air-cooled package air conditioners with refrigeration pump for data centers",
    abstract = "In recent years, the amount of energy consumed by data centers has tended to increase. Therefore, power savings are strongly suggested. Data centers must be cooled year-round due to the extremely large amount of heat emitted from the IT devices. Therefore, to decrease year-round energy consumption, it is important to use low-temperature outdoor air during cool seasons such as mid-to-late fall and early spring and cold seasons like winter. Thus, we investigated cooling systems that use low-temperature outdoor air, and we developed a package air conditioner (A/C) that has cooling functions that use outdoor air. The new A/C combines a compression cycle and a cycle that stops the compressor and circulates coolant with a pump; it operates by switching to a compression cycle when the outdoor temperature is high and switching to a pump cycle when the outdoor temperature is low. Specifically, the pump cycle is the system of taking the low-temperature outdoor air into a coolant cycle from the heat exchanger in the outdoor unit (indirect outdoor-air cooling method) and transporting cold energy into the room with a pump. The A/C reduces the energy consumption in low outdoor temperatures by operating in favor of the efficient pump cycle. In this report, in order to verify the characteristics of the A/C, we built a simulation mathematical model. In addition, we verified the validity of the mathematical model compared to the measured value of the prototype. We show the effects of refrigerant circulation and outdoor-air temperature as an example of the verification simulation using a mathematical model. We calculated the annual energy consumption of the package A/Cs with refrigeration pumps based on the outdoor-air temperature data and the operating efficiency of the outdoor-air temperature. Specifically, the A/C that we developed reduced energy consumption by 50{\%} in New York and 53{\%} in Chicago, compared to the energy consumption of conventional computer-room A/Cs.",
    author = "Yuji Kohata and Yosuke Udagawa and Keisuke Sekiguchi and Masahide Yanagi and Kiyoshi Saito and Keisuke Ohno and Yasuhiro Naito and Tsuneo Uekusa",
    year = "2015",
    language = "English",
    isbn = "9781936504961",
    volume = "121",
    pages = "430--439",
    booktitle = "ASHRAE Transactions",
    publisher = "Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc.",

    }

    TY - GEN

    T1 - Characteristics of air-cooled package air conditioners with refrigeration pump for data centers

    AU - Kohata, Yuji

    AU - Udagawa, Yosuke

    AU - Sekiguchi, Keisuke

    AU - Yanagi, Masahide

    AU - Saito, Kiyoshi

    AU - Ohno, Keisuke

    AU - Naito, Yasuhiro

    AU - Uekusa, Tsuneo

    PY - 2015

    Y1 - 2015

    N2 - In recent years, the amount of energy consumed by data centers has tended to increase. Therefore, power savings are strongly suggested. Data centers must be cooled year-round due to the extremely large amount of heat emitted from the IT devices. Therefore, to decrease year-round energy consumption, it is important to use low-temperature outdoor air during cool seasons such as mid-to-late fall and early spring and cold seasons like winter. Thus, we investigated cooling systems that use low-temperature outdoor air, and we developed a package air conditioner (A/C) that has cooling functions that use outdoor air. The new A/C combines a compression cycle and a cycle that stops the compressor and circulates coolant with a pump; it operates by switching to a compression cycle when the outdoor temperature is high and switching to a pump cycle when the outdoor temperature is low. Specifically, the pump cycle is the system of taking the low-temperature outdoor air into a coolant cycle from the heat exchanger in the outdoor unit (indirect outdoor-air cooling method) and transporting cold energy into the room with a pump. The A/C reduces the energy consumption in low outdoor temperatures by operating in favor of the efficient pump cycle. In this report, in order to verify the characteristics of the A/C, we built a simulation mathematical model. In addition, we verified the validity of the mathematical model compared to the measured value of the prototype. We show the effects of refrigerant circulation and outdoor-air temperature as an example of the verification simulation using a mathematical model. We calculated the annual energy consumption of the package A/Cs with refrigeration pumps based on the outdoor-air temperature data and the operating efficiency of the outdoor-air temperature. Specifically, the A/C that we developed reduced energy consumption by 50% in New York and 53% in Chicago, compared to the energy consumption of conventional computer-room A/Cs.

    AB - In recent years, the amount of energy consumed by data centers has tended to increase. Therefore, power savings are strongly suggested. Data centers must be cooled year-round due to the extremely large amount of heat emitted from the IT devices. Therefore, to decrease year-round energy consumption, it is important to use low-temperature outdoor air during cool seasons such as mid-to-late fall and early spring and cold seasons like winter. Thus, we investigated cooling systems that use low-temperature outdoor air, and we developed a package air conditioner (A/C) that has cooling functions that use outdoor air. The new A/C combines a compression cycle and a cycle that stops the compressor and circulates coolant with a pump; it operates by switching to a compression cycle when the outdoor temperature is high and switching to a pump cycle when the outdoor temperature is low. Specifically, the pump cycle is the system of taking the low-temperature outdoor air into a coolant cycle from the heat exchanger in the outdoor unit (indirect outdoor-air cooling method) and transporting cold energy into the room with a pump. The A/C reduces the energy consumption in low outdoor temperatures by operating in favor of the efficient pump cycle. In this report, in order to verify the characteristics of the A/C, we built a simulation mathematical model. In addition, we verified the validity of the mathematical model compared to the measured value of the prototype. We show the effects of refrigerant circulation and outdoor-air temperature as an example of the verification simulation using a mathematical model. We calculated the annual energy consumption of the package A/Cs with refrigeration pumps based on the outdoor-air temperature data and the operating efficiency of the outdoor-air temperature. Specifically, the A/C that we developed reduced energy consumption by 50% in New York and 53% in Chicago, compared to the energy consumption of conventional computer-room A/Cs.

    UR - http://www.scopus.com/inward/record.url?scp=84938854637&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84938854637&partnerID=8YFLogxK

    M3 - Conference contribution

    AN - SCOPUS:84938854637

    SN - 9781936504961

    VL - 121

    SP - 430

    EP - 439

    BT - ASHRAE Transactions

    PB - Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc.

    ER -