Life cycle techno-enviro-economic assessment of dual-temperature evaporation transcritical CO2 high-temperature heat pump systems for industrial waste heat recovery

Dai, Baomin; Liu, Chen; Liu, Shengchun; Wang, Dabiao; Wang, Qilong; Zou, Tonghua; Zhou, Xuan

doi:10.1016/j.applthermaleng.2022.119570

Cited by 64 publications

(14 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Equation (18) shows the exergy related to an enthalpy flow rate. [ 35 ]

{\overset{E}{true}}_{normalH} = \overset{false˙}{m} \cdot false(h - h_{0} - T_{0} \cdot false(s - s_{0} false) false)

…”

Section: Numerical Modelingmentioning

confidence: 99%

“…Equation (18) shows the exergy related to an enthalpy flow rate. [35] ĖH ¼ ṁ ⋅ ðh À h 0 À T 0 ⋅ ðs À s 0 ÞÞ…”

Section: Exergy Calculationmentioning

confidence: 99%

“…However, current refrigerant assessment and selection methods usually only consider a fixed flowsheet, one case for the heat source and sink conditions, or constant compressor efficiencies. [25][26][27][28][29][30] Only a few studies cover the influence of the flowsheet [8,16,[31][32][33][34][35] or the conditions of heat sources and sinks. [22][23][24]36] Beyond the standard approach of constant compressor efficiencies, sometimes simple empirical compressor models were used.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

et al. 2023

View full text Add to dashboard Cite

The refrigerant used in heat pumps significantly influences the overall system performance. However, selecting a proper refrigerant is no trivial matter due to the heat pumps’ sensitivity to the selected flowsheet, components, and operating conditions. Herein, a holistic approach is used that covers all these interdependencies simultaneously considering the flowsheet, fluid‐dependent compressor efficiencies, and the operating point. Six low global warming potential (GWP<150) refrigerants are investigated, which include pure fluids, azeotropic mixtures, and zeotropic mixtures from different substance groups. For four flowsheets, the seasonal coefficient of performance (SCOP) by EN 14825 is calculated and serves as the assessment metric. The case study is based on typical conditions of residential heat pumps. The results show that the SCOPs substantially differ depending on the refrigerant and the flowsheet (reaching from 3.8 to 4.6). Differences in the performance of refrigerants for an equal flowsheet are mainly driven by compressor efficiency. However, these differences can be overcome by adjusting the flowsheet. In particular, when an internal heat exchanger is added, the refrigerant ranking is substantially changed. It is shown that R436A, which is inferior to R290 for the basic cycle, benefits more from an internal heat exchanger and reaches a competitive SCOP than R290.

show abstract

“…Equation (18) shows the exergy related to an enthalpy flow rate. [ 35 ]

{\overset{E}{true}}_{normalH} = \overset{false˙}{m} \cdot false(h - h_{0} - T_{0} \cdot false(s - s_{0} false) false)

…”

Section: Numerical Modelingmentioning

confidence: 99%

“…Equation (18) shows the exergy related to an enthalpy flow rate. [35] ĖH ¼ ṁ ⋅ ðh À h 0 À T 0 ⋅ ðs À s 0 ÞÞ…”

Section: Exergy Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

et al. 2023

View full text Add to dashboard Cite

show abstract

“…These materials can adsorb and release a large amount of heat upon phase transitions (crystallization or melting) and are of great promise for use in domestic heat storage devices. Such devices are essential for the rational use of thermal energy, which has become an increasingly important issue in view of environmental protection, energy conservation, and reduction of carbon emissions [ 3 ]. It is, therefore, crucial to describe the phase transition itself and related changes in the thermophysical properties of PCMs as accurately as possible.…”

Section: Introductionmentioning

confidence: 99%

Cooling-Rate Computer Simulations for the Description of Crystallization of Organic Phase-Change Materials

Nazarychev

Glova

Larin

et al. 2022

IJMS

View full text Add to dashboard Cite

A molecular-level insight into phase transformations is in great demand for many molecular systems. It can be gained through computer simulations in which cooling is applied to a system at a constant rate. However, the impact of the cooling rate on the crystallization process is largely unknown. To this end, here we performed atomic-scale molecular dynamics simulations of organic phase-change materials (paraffins), in which the cooling rate was varied over four orders of magnitude. Our computational results clearly show that a certain threshold (1.2 × 1011 K/min) in the values of cooling rates exists. When cooling is slower than the threshold, the simulations qualitatively reproduce an experimentally observed abrupt change in the temperature dependence of the density, enthalpy, and thermal conductivity of paraffins upon crystallization. Beyond this threshold, when cooling is too fast, the paraffin’s properties in simulations start to deviate considerably from experimental data: the faster the cooling, the larger part of the system is trapped in the supercooled liquid state. Thus, a proper choice of a cooling rate is of tremendous importance in computer simulations of organic phase-change materials, which are of great promise for use in domestic heat storage devices.

show abstract

“…Moreover, considering the pump start and stop period, they investigated the influences of viscosity on the internal flow [15]. Dai et al [16] proposed three novel transcritical CO 2 high-temperature heat pump systems to recover waste heat. Besides, in recent years, research on the starting of a multistage centrifugal pump [17] and a centrifugal pump with assisted valve [18] has also made some progress.…”

Section: Introductionmentioning

confidence: 99%

Evolution Characteristics of Energy Change Field in a Centrifugal Pump during Rapid Starting Period

Chen

Zhang

2022

Energies

View full text Add to dashboard Cite

Although the energy change field in the centrifugal pump has been investigated under quasi-steady conditions (QSC), equivalent information is not yet known during the rapid starting period (RSP). A centrifugal pump loop system is constructed to investigate the energy change field in the centrifugal pump during RSP. The RSP is selected as a linear rotational speed from 0 rev/min to 2900 rev/min (design rotational speed) and a constant valve opening of 0.569. Results show that the flow rate lags behind the pump head value with the linear increase in rotational speed. The large values of partial derivations of mechanical energy in normal and tangential components are mainly concentrated at the impeller outlet, whose position is insensitive to rotational speed. The region of dominant energy loss is negatively correlated with rotational speed, and an opposite phenomenon is observed in the region of dominant energy increase. With the rotational speed increasing, the mean energy gradient function in the pump impeller and pump volute gradually increases, and the slope of the former is less than that of the latter. After reaching the design rotational speed, the energy change field gradually approaches that under quasi-steady conditions.

show abstract

Life cycle techno-enviro-economic assessment of dual-temperature evaporation transcritical CO2 high-temperature heat pump systems for industrial waste heat recovery

Cited by 64 publications

References 65 publications

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

Cooling-Rate Computer Simulations for the Description of Crystallization of Organic Phase-Change Materials

Evolution Characteristics of Energy Change Field in a Centrifugal Pump during Rapid Starting Period

Contact Info

Product

Resources

About