High Temperature Air Source Heat Pump Coupled with Thermal Energy Storage: Comparative Performances and Retrofit Analysis

Le, Khoa Xuan; Huang, Ming Jun; Shah, Nikhilkumar; Wilson, Christopher; Artain, Paul Mac; Byrne, Raymond; Hewitt, Neil

doi:10.1016/j.egypro.2019.01.857

Cited by 14 publications

(10 citation statements)

References 3 publications

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“…The HTF volume flow rate range (2.0-6.0 L/min) was selected to correspond to the range suggested for the Kingspan Thermomax HP evacuated tube solar collector (120 L/h to 480 L/h) [29]. Thermocouple sensor T 25 was located at the base of the storage unit, near to the edge of the store and used to determine when the store was fully charged.…”

Section: Methodsmentioning

confidence: 99%

“…The selected HTF inlet temperatures for charging experiments were 70, 75, and 80 • C to provide temperature differences of approximately 8, 13, and 18 • C between the inlet temperature of the HTF and the average melting temperature of the PCM. These values are representative of output temperatures from high-temperature air source heat pumps (HT-ASHP) that can be coupled with thermal energy storage [29] and solar water heating systems [30].…”

Section: Methodsmentioning

confidence: 99%

“…The HTF volume flow rate range (2.0-6.0 L/min) was selected to correspond to the range suggested for the Kingspan Thermomax HP evacuated tube solar collector (120 L/h to 480 L/h) [29].…”

Section: Methodsmentioning

confidence: 99%

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Thermal Performance Analysis of the Charging/Discharging Process of a Shell and Horizontally Oriented Multi-Tube Latent Heat Storage System

Fadl

Eames

2020

Energies

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In this study, the thermal performance of latent heat thermal energy storage system (LHTESS) prototype to be used in a range of thermal systems (e.g., solar water heating systems, space heating/domestic hot water applications) is designed, fabricated, and experimentally investigated. The thermal store comprised a novel horizontally oriented multitube heat exchanger in a rectangular tank (forming the shell) filled with 37.8 kg of phase change material (PCM) RT62HC with water as the working fluid. The assessment of thermal performance during charging (melting) and discharging (solidification) was conducted under controlled several operational conditions comprising the heat transfer fluid (HTF) volume flow rates and inlet temperatures. The experimental investigations reported are focused on evaluating the transient PCM average temperature distribution at different heights within the storage unit, charging/discharging time, instantaneous transient charging/discharging power, and the total cumulative thermal energy stored/released. From the experimental results, it is noticed that both melting/solidification time significantly decreased with increase HTF volume flow rate and that changing the HTF inlet temperature shows large impacts on charging time compared to changing the HTF volume flow rate. During the discharging process, the maximum power output was initially 4.48 kW for HTF volume flow rate of 1.7 L/min, decreasing to 1.0 kW after 52.3 min with 2.67 kWh of heat delivered. Based on application heat demand characteristics, required power levels and heat demand can be fulfilled by employing several stores in parallel or series.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Thermal Performance Analysis of the Charging/Discharging Process of a Shell and Horizontally Oriented Multi-Tube Latent Heat Storage System

Fadl

Eames

2020

Energies

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“…However, the pros and cons including the efficiency improvement and carbon emissions savings comparison is important to provide solid information to the policy makers and homeowners. The HP studies as a domestic retrofit technology could mainly be divided into two categories based on the supply temperature, i.e., (a) low to medium (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) • C) and high supply temperature (55 • C), and (b) very high supply temperature (60 • C and above). The literature on the domestic retrofit applications were mainly based on the predictions/and field trials of the commercially available units, manufacturer data information with no control over supply temperature, assuming nominal value for heat supply temperature [23,24], and without considering the heat supply temperature, control mode, building insulations, climatic conditions simultaneous impact.…”

Section: Literature Reviewmentioning

confidence: 99%

Domestic Retrofit Assessment of the Heat Pump System Considering the Impact of Heat Supply Temperature and Operating Mode of Control—A Case Study

et al. 2021

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In this study, performance assessment of the variable speed compressor-based air source heat pump (ASHP) system as a domestic retrofit technology instead of fossil fuel-based heating technologies for the 1900s Mid terraced house is investigated. The assessment was conducted considering operating mode of control and heat supply temperature impact of the system. In the literature, ASHP system experimental development with variable speed mode (VSM) of control in comparison to fixed speed mode (FSM) of control at low to medium and high heat supply temperature in the context of UK was found with very limited number of studies, but without considering retrofit application. The focus of the earlier studies was on the individual components and performance improvement. The designed heat pump (HP), developed, and tested at constant heat load, simulating the real domestic heat demand under the controlled laboratory conditions and numerical modeling is utilized for the analysis purposes. The HP performance, energy demand, carbon emissions, and cost varies significantly due to changing heat supply temperature (35 °C, 45 °C, and 55 °C), control mode and accordingly the carbon emission and cost savings are achieved. The oil and gas boilers ranges from conventional to highly efficient type and evaluated in terms of annual running cost, energy consumptions, and carbon emissions in comparison with the HP system. Additionally, a comparative study with the existing retrofitted very high temperature ASHP inside the house is conducted. The developed HP at 55 °C could not defeat the very high heat supply temperature HP system (75 °C supply temperature) in performance and cost savings but become attractive at low supply temperature (35 °C). The HP system in VSM at low heat supply temperature instead of gas boiler (90% efficiency) could cut the annual carbon emissions by 59% but with additional 6% running cost for the Mid terraced test house in Belfast climatic conditions.

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“…The ASHP performance depends on the operating conditions, the environment and the system design [17]. In addition, different refrigerants [18] and control modes of the equipment [19] exist and were analysed. Eom et al used deep learning to implement a method to predict the heating capacity and power consumption of the ASHP due to frost growth [20].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Frost Formation Influence on an Air Source Heat Pump Evaporator

2021

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The application of heat pumps in the heating systems of buildings in the cold or transitional season is becoming an increasingly common practice not only in Lithuania but in other countries as well. Due to the growing popularity of air-to-air or air-to-water heat pumps in the building sector, the problem of the evaporator heat exchanger freezing is also becoming more and more relevant. As the outdoor temperature drops, so does the heat pump’s coefficient of performance (COP) for heating. The freezing of the evaporator surface increases the energy consumption of the system, has a negative effect on heat exchange, distorts the normal operating cycle of the heat pump and the energy is wasted for defrosting processes. This article describes the experimental investigation of an air-to-water heat pump, presents the results obtained during the experiments and their interfaces. The experiments were carried out during the transitional/cold season. It was found that frost formation on the evaporator started when the outdoor temperature was <3.5 °C and the relative humidity reached 88%. The defrosting cycle took an average of 5 min. The impact of the evaporator freezing on the operation and COP of the heat pump was assessed.

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High Temperature Air Source Heat Pump Coupled with Thermal Energy Storage: Comparative Performances and Retrofit Analysis

Cited by 14 publications

References 3 publications

Thermal Performance Analysis of the Charging/Discharging Process of a Shell and Horizontally Oriented Multi-Tube Latent Heat Storage System

Thermal Performance Analysis of the Charging/Discharging Process of a Shell and Horizontally Oriented Multi-Tube Latent Heat Storage System

Domestic Retrofit Assessment of the Heat Pump System Considering the Impact of Heat Supply Temperature and Operating Mode of Control—A Case Study

Experimental Investigation of Frost Formation Influence on an Air Source Heat Pump Evaporator

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