Advances, challenges and outlooks in frost-free air-source heat pumps: A comprehensive review from materials, components to systems

Huang, Shifang; Yu, Hanfei; Zhang, Muxing; Qu, Hongshuo; Wang, Libo; Zhang, Chenyu; Yuan, Yubo; Zhang, Xiaosong

doi:10.1016/j.applthermaleng.2023.121163

Cited by 25 publications

(3 citation statements)

References 120 publications

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“…However, when operating in cold regions, when the surface temperature of the outdoor evaporator is lower than the dew point temperature of the ambient air, frosting occurs on the surface of the evaporator, thereby increasing the thermal resistance of the evaporator and the flow resistance of the air. In order to maintain stable operation, some refrigerant steam is used for frequent defrosting, thereby reducing the heating capacity and resulting in reduced operating efficiency [16][17][18][19]. Water source heat pumps use water bodies such as ponds, lakes, rivers, seawater, groundwater, or sewage as their heat source.…”

Section: Introductionmentioning

confidence: 99%

Operation Mode and Energy Consumption Analysis of a New Energy Tower and Ground Source-Coupled Heat Pump System

Zhang,

Wu,

et al. 2023

Energies

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In order to solve the problems of performance degradation in energy tower heat pump (ETHP) systems under low temperature conditions and soil heat imbalances in ground source heat pump (GSHP) systems in cold regions, a new coupled system of ETHP and GSHP systems (the ET–GSHP system) and its operating mode were proposed. The mathematical model of the system was constructed along with the system’s form and operation scheme. The COP (coefficient of performance) and total energy consumption of the coupled system were then simulated and studied under a number of common operating situations. The heating season is divided into four periods based on varying outdoor ambient temperatures: the first period operates in series mode and has an average outdoor temperature of 2.38 °C; the second period operates in parallel mode and has an average outdoor temperature of −8.56 °C; the third period uses soil source heat pumps to operate separately; and the fourth period operates in series mode and has an average outdoor temperature of −11.32 °C. Operation of the coupled system in four periods was simulated and analyzed, and the operational efficiency and energy saving of the system were analyzed using an actual commercial building in a cold region as an example. The results demonstrate that the ET–GSHP system’s overall energy consumption during the heating period is reduced by 4.34% when compared to the traditional GSHP systems; the system’s COP can maintain a high level throughout the heating period, with an average COP of 3.315; and the soil temperature at the conclusion of the heating period is 25 °C, which is 8.89 °C higher than that of the traditional GSHP system, providing a guarantee of summer heat return. The new ET–GSHP system significantly boosts the efficiency of the system’s operation, achieves effective coupling between various heat sources through multi-stage control, and offers improved energy-saving advantages.

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Section: Introductionmentioning

confidence: 99%

Operation Mode and Energy Consumption Analysis of a New Energy Tower and Ground Source-Coupled Heat Pump System

Zhang,

Wu,

et al. 2023

Energies

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“…As one of the main energy consumers, buildings have a great potential to save energy and reduce emissions (Jin et al, 2021). And air source heat pumps (ASHPs) have been widely used as heat output units in industrial projects and have achieved significant energy savings (Huang et al, 2023). Therefore, Under the development of integrated energy, it's important to improve the system's overall energy efficiency to save more energy in the electric power system.…”

Section: Introductionmentioning

confidence: 99%

Optimal energy management of a group of air source heat pumps in a low-carbon industrial park considering its cold island effect

Liang,

Jin,

Jia

et al. 2023

Preprint

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This paper proposes an optimal energy management method for a group of air source heat pumps (ASHPs) in a low-carbon industrial park while considering the cold island effect of the ASHPs. The low-carbon industrial park is a real case in Binhai New District, Tianjin, China where 14 factories are based in. The heating loads of the 14 factories are satisfied by a group of ASHPs that are powered by distributed photovoltaic (PV) generations to reduce the carbon emissions of the whole industrial park. First, an optimal scheduling model for the operation of the group of the ASHPs considering the cold island effect is developed. The unit commitment of the ASHPs within the group is optimized while considering the operational constraints of each ASHP unit. Furthermore, the cold island effect of all the ASHPs is considered as a constraint to avoid the influence of the cold island effect as far as possible and thus keep the ASHPs in their efficient states. Then, the resistance-capacitance (RC) network is used to model the thermal dynamics of the factory buildings in the park. The thermal inertia and the schedules of the employee's working hours are also considered to explore the flexibility of the factory buildings. Finally, the operator of the industrial park can actively control the group of ASHP units to reduce the heating costs and meet the comfort requirements of the factory buildings. Numerical studies show that the proposed strategy can help to reduce the heating costs, improve the efficiency of the ASHP and reduce the carbon emissions as well for the low-carbon industrial park.

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“…Urbanization is closely intertwined with building energy consumption, a factor that has exhibited a persistent upward trajectory. This escalating trend underscores the growing significance of building energy consumption within the broader landscape of societal energy utilization, currently approximating 30% (Xu and Wang, 2020;Olu-Ajayi et al, 2022;Huang et al, 2023). The building roof, often metaphorically termed the "fifth facade," has transcended its conventional structural role, evolving into a multifaceted platform with pronounced energy-efficient attributes.…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of energy consumption of building roof energy-saving technologies based on time difference comparison test

Zhao,

Hai,

et al. 2023

Front. Energy Res.

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The roof plays a pivotal role as it directly engages with solar radiation absorption and external heat exchange, significantly influencing the building’s overall energy dynamics. To assess the performance of green roofs and cool roofs, a roof performance test facility was established in Nanjing. Time-difference comparison experiments were conducted to measure and analyze the energy-saving effects of cool roofs, green roofs, and conventional roofs during both summer and winter conditions. The study aimed to investigate how their thermal performance impacts building energy consumption. The study’s findings reveal that under summer conditions, the incorporation of a cool roof system leads to a substantial enhancement in energy efficiency, achieving an impressive 13.2% energy savings compared to conventional roofing solutions. In contrast, the implementation of a green roof system results in a more modest energy-saving rate of 4.1%. Transitioning to winter conditions, the adoption of a cool roof system shows a marginal increase of 2.8% in energy consumption compared to conventional roofs. Interestingly, the green roof system stands out as an energy-efficient option during winter, demonstrating a significant 4.9% reduction in energy consumption. This approach ensured reliable and valid results to provide a comprehensive view of how different roof types respond to varying climatic conditions.

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Advances, challenges and outlooks in frost-free air-source heat pumps: A comprehensive review from materials, components to systems

Cited by 25 publications

References 120 publications

Operation Mode and Energy Consumption Analysis of a New Energy Tower and Ground Source-Coupled Heat Pump System

Operation Mode and Energy Consumption Analysis of a New Energy Tower and Ground Source-Coupled Heat Pump System

Optimal energy management of a group of air source heat pumps in a low-carbon industrial park considering its cold island effect

Experimental analysis of energy consumption of building roof energy-saving technologies based on time difference comparison test

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