The performance of a transcritical CO2 cycle with an internal heat exchanger for hot water heating

Kim, Sung Goo; Kim, Yoon Jo; Lee, Gilbong; Kim, Min Soo

doi:10.1016/j.ijrefrig.2005.03.004

Cited by 71 publications

(30 citation statements)

References 7 publications

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“…Similar observations on the impact of water inlet temperature were made in models developed by White (2002), Stene (2005), and Sarkar et al (2006;. Kim et al (2005) discussed the impact of a SLHX on system level performance of a CO 2 heat pump for water heating. One impact of the SLHX is the increase in superheating of the refrigerant at the compressor suction port.…”

Section: Introductionsupporting

confidence: 54%

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

Goodman¹,

Fronk

Garimella

2011

International Journal of Refrigeration

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This paper presents the development of a transcritical CO 2 heat pump water heating system model incorporating analytical heat exchanger models and an empirical compressor model. This study investigated the effects of a suction line heat exchanger (SLHX) and once-through versus multi-pass water heating schemes. The once-through systems outperformed the multi-pass systems by 10% for the system without a SLHX and 15% with a SLHX. However, a gas cooler twice as large is required. The SLHX was shown to benefit system performance at higher evaporator temperatures with improvements of 16.5% for the once-through and 4% for the multi-pass systems. This study can be used to improve the design of microchannel based transcritical CO 2 heat pumps; evaluate the impact of varying water inlet temperature, desired outlet temperature and evaporation temperature on system performance; and quantify the effect of differential diurnal electricity rates on system operating costs for these different operation schemes.

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Section: Introductionsupporting

confidence: 54%

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

Goodman¹,

Fronk

Garimella

2011

International Journal of Refrigeration

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“…Another experimental study on simultaneous air conditioning and water heating has yielded promising results as an energy recovery system [18]. Kim et al [19] have done experimental study on CO 2 heat pump with internal heat exchanger using water as secondary fluid for both sides with emphasis only on heating. However, a review of the open literature shows that studies on the effects of expansion valve opening on system behaviour are scarce.…”

Section: Introductionmentioning

confidence: 99%

A transcritical CO₂heat pump for simultaneous water cooling and heating: Test results and model validation

Sarkar

Bhattacharyya

Mopuri

2009

Int. J. Energy Res.

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SUMMARYWorking prototype of a transcritical CO 2 heat pump system for simultaneous cooling and heating of water is designed and developed based on numerical simulation studies. System behaviour and performance of the system have been studied experimentally for various operating parameters such as system pressure, water mass flow rate, water inlet temperature and expansion valve opening. Finally, the system simulation model predictions have been validated by the test data. Test results show the effect of water mass flow rate to be modest for both evaporator and gas cooler, whereas the effect of water temperature at the inlet to the gas cooler on system performance is significant. The expansion valve opening has a significant effect as well near the full valve closing condition (up to 201). Validation of the simulation model shows reasonably good agreement (a maximum deviation of 15%) with the test data exhibiting fairly similar trends.

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“…Authors of paper [4] examined influence of the length of pipes of regenerative intermediate heat exchanger on the parameters of supercritical cycle of CO 2 and COP of heat pump for the purpose of reaching its optimum value. At the same time, the influence of optimum parameters of regenerative heat exchanger on the remaining system elements was not explored, and the optimization of the system as a whole was not carried out.…”

Section: K U Z N E T S O Vmentioning

confidence: 99%

Thermoeconomic optimization of supercritical refrigeration system with the refrigerant R744 (CO2)

Kuznetsov

Харлампиди

Tarasova

et al. 2016

EEJET

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Розроблена термоекономічна модель холо-дильної установки, що працює по надкритич-ному циклу CO 2 у якості холодагенту. Модель побудована для установки типу "повітря -повітря" і дозволяє при оптимізації конструк-ції і виборі економічних режимів роботи одно-часно враховувати як термодинамічні, так і економічні параметри. Приведені результати оптимізації, що забезпечують умови досяг-нення мінімального рівня приведених витрат Ключові слова: термоекономічна модель, надкритичний цикл, ексергія, приведені ви-трати Разработана термоэкономическая модель холодильной установки, работающей по сверхкритическому циклу CO 2 в качестве хла-дагента. Модель построена для установки типа «воздух -воздух» и позволяет при опти-мизации конструкции и выборе экономичных режимов работы одновременно учитывать как термодинамические, так и экономические параметры. Приведены результаты оптими-зации, обеспечивающие условия достижения минимального уровня приведенных затрат Ключевые слова: термоэкономическая мо-дель, сверхкритический цикл, эксергия, приве-денные затраты UDC 621.577;621.564

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The performance of a transcritical CO2 cycle with an internal heat exchanger for hot water heating

Cited by 71 publications

References 7 publications

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

A transcritical CO₂heat pump for simultaneous water cooling and heating: Test results and model validation

Thermoeconomic optimization of supercritical refrigeration system with the refrigerant R744 (CO2)

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The performance of a transcritical CO2 cycle with an internal heat exchanger for hot water heating

Cited by 71 publications

References 7 publications

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

Transcritical carbon dioxide microchannel heat pump water heaters: Part II – System simulation and optimization

A transcritical CO2heat pump for simultaneous water cooling and heating: Test results and model validation

Thermoeconomic optimization of supercritical refrigeration system with the refrigerant R744 (CO2)

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Product

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A transcritical CO₂heat pump for simultaneous water cooling and heating: Test results and model validation