Theoretical evaluation of different high-temperature heat pump configurations for low-grade waste heat recovery

Mateu-Royo, Carlos; Navarro-Esbrí, Joaquin; Amat-Albuixech, Marta; Molés, Franciscó

doi:10.1016/j.ijrefrig.2018.04.017

Cited by 69 publications

(23 citation statements)

References 24 publications

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“…The COP and economic evaluation of HFC‐134a, HFO‐1234yf, HFC‐245fa, HFO‐1336mzz(Z), and HFO‐1234ze(E) at lift temperatures of 30°C and 50°C in high‐temperature heat pump system were investigated by Juhasz; the results indicated that HFO‐1336mzz(Z) has a higher COP and economic justification than that of other working fluids. Mateu‐Royo et al investigated the energy performance and volumetric heating capacity of n ‐pentane, butane, HCFO‐1233zd(E), and HFO‐1336mzz(Z) as low GWP alternative fluids to HFC‐245fa in five high‐temperature heat pump configurations; the results showed that HFO‐1336mzz(Z) achieves medians in these parameters. They also studied the performance of HFO‐1336mzz(Z), HCFO‐1233zd(E), and HCFO‐1224yd(Z) in high‐temperature heat pump system as low GWP alternative fluids to replace HFC‐245fa; the results represented that HFO‐1336mzz(Z) augments the COP about 21% than HFC‐245fa .…”

Section: Introductionmentioning

confidence: 99%

Thermal stability and decomposition mechanism of HFO‐1336mzz(Z) as an environmental friendly working fluid: Experimental and theoretical study

et al. 2019

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Summary HFO‐1336mzz(Z) is a promising working fluid used in high‐temperature heat pump and organic Rankine cycle (ORC) system because of its environmental friendly features and good thermal performance. In this work, a test system is designed to assess the thermal stability of HFO‐1336mzz(Z). The fluoride ion concentration is used as an indicator of HFO‐1336mzz(Z) dissociation. The experimental results show that the pressure has a great effect on the dissociation of HFO‐1336mzz(Z) and the dissociation temperatures of HFO‐1336mzz(Z) at 2.1, 3.1, and 4.0 MPa for 24 hours are 310°C to 330°C, 290°C to 310°C, and 270°C to 290°C, respectively. The decomposition products of HFO‐1336mzz(Z) are measured by a Fourier transform infrared spectrometer (FTIR); the main decomposition products are HF, CF4, CHF3, C2F4, C2F6, C2HF5, and C3F8. Finally, density functional theory (DFT) method is used to study the decomposition mechanism of HFO‐1336mzz(Z). The main initial decomposition reaction is the fracture of CC bond into C–C bond, and then the CF3 group is separated from HFO‐1336mzz(Z) molecule to produce CF3 radical. H, F‐abstraction, and combination reactions are important in the consequent reactions to generate the main decomposition products.

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Section: Introductionmentioning

confidence: 99%

Thermal stability and decomposition mechanism of HFO‐1336mzz(Z) as an environmental friendly working fluid: Experimental and theoretical study

et al. 2019

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“…20. The first observation can be justified attending to that mentioned by Mateu-Royo et al [11], who mentions that the refrigerant with the highest IHX benefit is the one that performs worse in the basic cycle. Then, the similarity between the traditional refrigerant HFC-245fa and the alternative low-GWP refrigerants can be explained attending to the similar thermophysical properties of both fluids, highlighted in Mateu-Royo et al [32].…”

Section: Semi-empirical Low-gwp Refrigerants Assessmentmentioning

confidence: 96%

“…While at lower temperatures, traditional refrigerants such as HFC-134a, HFC-32, and HC-290 can be used in the industry [9], for high-temperature applications other fluids must be considered [10]. Moreover, for higher heat sink temperatures and temperature lifts, the COP can be improved using advanced configurations, different from the basic cycle [11].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, current research and development of HTHPs aims at covering higher heat sink temperatures with suitable working fluids and energy efficient configurations. The development status of HTHPs configurations is still mostly limited to theoretical analysis, such as those performed by Cao et al, and Mateu-Royo et al [11,12], which considered an external heat exchanger in one and two stages, or those performed by Mota-Babiloni et al and Yang et al [13,14], which considered HTHP cascades. Moreover, an intensive theoretical study was performed on the energy performance benefits provided by the use of zeotropic mixtures [15,16].…”

Section: Introductionmentioning

confidence: 99%

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Experimental exergy and energy analysis of a novel high-temperature heat pump with scroll compressor for waste heat recovery

et al. 2019

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The industrial sector demands novel sustainable energy systems to advance in its decarbonisation and meet the targets of the Paris Agreement for the climate change mitigation. High-Temperature Heat Pumps (HTHPs) are being investigated as a feasible energy conversion technology alternative to traditional fossil fuel boilers. This paper presents the first experimental results of an HTHP prototype equipped with a modified scroll compressor and internal heat exchanger (IHX). The elements of the main and secondary circuits are presented, as well as the test methodology and heat balances are exposed. The tests have been performed using HFC-245fa at heat source temperatures between 60 and 80 °C, and heat sink temperatures between 90 and 140 °C. The heating capacity and coefficient of performance (COP) varied between 10.9 and 17.5 kW and between 2.23 and 3.41, respectively. An exergetic analysis indicated that the expansion valve was the component with the worst second law efficiency and the compressor presented the highest potential improvement over the other cycle components. A computational analysis of low global warming potential (GWP) refrigerant alternatives was carried out, which confirmed the benefits of using an internal heat exchanger (IHX) and the good performances of the low-GWP refrigerants: HCFO-1224yd(Z), HCFO-1233zd(E), and HFO-1336mzz(Z). Finally, we proved that the proposed system can save up to 57% of the equivalent CO2 emissions of a natural gas boiler. This paper provides a reference for the high-temperature heat pump recovery of the lowgrade waste heat from industrial energy processes.

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“…In the context of high temperature HPs, using R717, R365mfc, R1234ze(E), and R1234ze(Z) [12] and R1233zd(E) and 1336mzz(Z) [13], Kondou and Koyama [12] and Mateu-Royo et al [13] evaluated the theoretical performance of different cycle configurations with hydrofluoroolefines in order to demonstrate the potential use of high temperature HPs to recover waste heat and reduce the primary energy consumption.…”

Section: Introductionmentioning

confidence: 99%

Energetic and Exergetic Analysis of Low Global Warming Potential Refrigerants as Substitutes for R410A in Ground Source Heat Pumps

et al. 2019

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In the European Union (EU), buildings are responsible for about 40% of the total final energy consumption, and 36% of the European global CO2 emissions. The European Commission released directives to push for the enhancement of the buildings energy performance and identified, beside the retrofit of the current building stock, Heating, Ventilation, and Air Conditioning (HVAC) systems as the other main way to increase renewable energy sharing and overall building energy efficiency. For this purpose, Ground Source Heat Pumps (GSHPs) represent one of the most interesting technologies to provide energy for heating, cooling, and domestic water production in residential applications, ensuring a significant reduction (e.g., up to 44% compared with air-source heat pumps) of energy consumption and the corresponding emissions. At present, GSHPs mainly employ the refrigerant R410A as the working fluid, which has a Global Warming Potential (GWP) of 2087. However, following the EU Regulation No. 517/2014 on fluorinated greenhouse gases, this high GWP refrigerant will have to be substituted for residential applications in the next years. Thus, to increase the sustainability of GSHPs, it is necessary to identify short time alternative fluids with lower GWP, before finding medium-long term solutions characterized by very low GWP. This is one of the tasks of the UE project "Most Easy, Efficient, and Low-Cost Geothermal Systems for Retrofitting Civil and Historical Buildings" (acronym GEO4CIVHIC). Here, a thorough thermodynamic analysis, based on both energy and exergy analysis, will be presented to perform a comparison between different fluids as substitutes for R410A, considered as the benchmark for GSHP applications. These fluids have been selected considering their lower flammability with respect to hydrocarbons (mainly R290), that is one of the main concerns for the companies. A parametric analysis has been performed, for a reversible GSHP cycle, at various heat source and sink conditions, with the aim to identify the fluid giving the best energetic performance and to evaluate the distribution of the irreversibilities along the cycle. Considering all these factors, R454B turned out to be the most suitable fluid to use in a ground source heat pump, working at given conditions. Special attention has been paid to the compression phase and the heat transfer in evaporator and condenser.

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Theoretical evaluation of different high-temperature heat pump configurations for low-grade waste heat recovery

Cited by 69 publications

References 24 publications

Thermal stability and decomposition mechanism of HFO‐1336mzz(Z) as an environmental friendly working fluid: Experimental and theoretical study

Thermal stability and decomposition mechanism of HFO‐1336mzz(Z) as an environmental friendly working fluid: Experimental and theoretical study

Experimental exergy and energy analysis of a novel high-temperature heat pump with scroll compressor for waste heat recovery

Energetic and Exergetic Analysis of Low Global Warming Potential Refrigerants as Substitutes for R410A in Ground Source Heat Pumps

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