A new method for preventing air-source heat pump water heaters from frosting

Zhang, Li; Fujinawa, Takeshi; Saikawa, Masatoshi

doi:10.1016/j.ijrefrig.2012.04.004

Cited by 56 publications

(20 citation statements)

References 23 publications

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“…The FFASHP water heater system coupled a solid desiccant is generally composed of a conventional ASHP subsystem, a desiccant-coated heat exchanger [83] or an extra heat exchanger coated by a solid desiccant with an energy storage device (EHECSD) [10,80]. The systems could not only prevent frosting in heating mode but supply uninterrupted heating in regeneration mode.…”

Section: Ffashp Water Heater System Descriptionmentioning

confidence: 99%

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Frosting Phenomenon and Frost-Free Technology of Outdoor Air Heat Exchanger for an Air-Source Heat Pump System in China: An Analysis and Review

Zhang

Zhang³

et al. 2018

Energies

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Frost layer on the outdoor air heat exchanger surface in an air-source heat pump (ASHP) can decrease the system coefficient of performance (COP). Although the common defrosting and anti-frosting methods can improve the COP, the periodic defrosting not only reduces the system energy efficiency but also deteriorates the indoor environment. To solve these problems, it is necessary to clearly understand the frosting phenomenon and to achieve the system frost-free operation. This paper focused firstly on the analyses of frosting pathways and frosting maps. Followed by summarizing the characteristics of frost-free technologies. And then the performances of two types of frost-free ASHP (FFASHP) systems were reviewed, and the exergy and economic analysis of a FFASHP heating system were carried out. Finally, the existing problems related to the FFASHP technologies were proposed. Results show that the existing frosting maps need to be further improved. The FFASHP systems can not only achieve continuous frost-free operation but reduce operating cost. And the total COP of the FFASHP heating system is approximately 30–64% higher than that of the conventional ASHP system under the same frosting conditions. However, the investment cost of the FFASHP system increases, and its reliability also needs further field test in a wider frosting environment. In the future, combined with a new frosting map, the control strategy for the FFASHP system should be optimized.

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Section: Ffashp Water Heater System Descriptionmentioning

confidence: 99%

“…Figure 16. Schematic diagram of the FFASHP water heater system based on solid desiccant [83]. Table 9.…”

Section: Ffashp Water Heater System Descriptionmentioning

confidence: 99%

Frosting Phenomenon and Frost-Free Technology of Outdoor Air Heat Exchanger for an Air-Source Heat Pump System in China: An Analysis and Review

Zhang

Zhang³

et al. 2018

Energies

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“…tube wall systems in winter [18][19][20][21][22]. For example, a frost-free air-source heat pump water heating system with integrated solid desiccant was proposed [20]; comprising a conventional ASHP and an extra DCHE, in which the outside air traverses the DCHE before entering the heat pump evaporator.…”

Section: Introductionmentioning

confidence: 99%

“…For example, a frost-free air-source heat pump water heating system with integrated solid desiccant was proposed [20]; comprising a conventional ASHP and an extra DCHE, in which the outside air traverses the DCHE before entering the heat pump evaporator. Because the dew point of the air at the DCHE outlet is lower than the evaporation temperature of the refrigerant in the evaporator, frost-free operation could be realized in the system.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on heat and mass transfer characteristics for a desiccant-coated fin-tube heat exchanger

Saikawa

Fujinawa

2015

International Journal of Heat and Mass Transfer

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“…Evaporator frosting and subsequent need for defrosting at low ambient temperatures at ASHPs causes reduced energy efficiency and heating shut down (Zhang et al 2012). Different solutions to delay frosting and improve defrosting efficiency are used.…”

Section: Introductionmentioning

confidence: 99%

Analysis of air-to-water heat pump in cold climate: comparison between experiment and simulation

Januševičius

Streckienė

2015

Science - Future of Lithuania

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abstract. Heat pump systems are promising technologies for current and future buildings and this research presents the performance of air source heat pump (ASHP) system. The system was monitored, analysed and simulated using TRNSYS software. The experimental data were used to calibrate the simulation model of ASHP. The specific climate conditions are evaluated in the model. It was noticed for the heating mode that the coefficient of performance (COP) varied from 1.98 to 3.05 as the outdoor temperature changed from -7.0 ºC to +5.0 ºC, respectively. TRNSYS simulations were also performed to predict seasonal performance factor of the ASHP for Vilnius city. It was identified that seasonal performance prediction could be approximately 15% lower if frost formation effects are not included to air-water heat pump simulation model.

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A new method for preventing air-source heat pump water heaters from frosting

Cited by 56 publications

References 23 publications

Frosting Phenomenon and Frost-Free Technology of Outdoor Air Heat Exchanger for an Air-Source Heat Pump System in China: An Analysis and Review

Frosting Phenomenon and Frost-Free Technology of Outdoor Air Heat Exchanger for an Air-Source Heat Pump System in China: An Analysis and Review

Experimental study on heat and mass transfer characteristics for a desiccant-coated fin-tube heat exchanger

Analysis of air-to-water heat pump in cold climate: comparison between experiment and simulation

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