Two-stage System Research Articles

Performance analysis of water refrigerant heat pump with different configurations for high-temperature application

Water is a promising working fluid for high-temperature heat pumps (HTHPs) with the advantages of being cheap, safe, stable, environmentally friendly, non-toxic, and non-flammable. HTHPs using water as a refrigerant not only can reduce greenhouse gas emissions in the industrial sectors by recovering waste heat but also have no adverse effect on the environment if the refrigerant leaks. This article evaluates the safety, energy, and exergy performance of six designed HTHP configurations with water refrigerant by analyzing the discharge superheat, power consumption, heating capacity, COP, and exergy efficiency—at different condensation and evaporation temperatures. The results indicated that water injection and intercooling can effectively decrease the discharge superheat to ensure safety performance. Among these systems, two-stage cycles can supply higher output temperatures and have better system performance compared to single-stage cycles at high-temperature lifts and large compression ratio conditions. The two-stage system with a flash tank (TS-FT) has the biggest heating capacity, the best COP, and the best exergy efficiency. With an evaporation temperature of 80°C and condensation temperature of 140°C, the COP is 4.14 and the exergy efficiency is 70.9% for the TS-FT. Compared with the single-stage ordinary system (SS-OS), the COP of the TS-FT has an increment of 36.6%. The exergy efficiency of the TS-FT is 19.8% higher than that of the SS-OS. Considering the aforementioned theoretical analysis, the TS-FT with the best safety, energy, and exergy performance is the optimal HTHP system with water refrigerant for high-temperature applications.

Foreign bank presence and inclusive growth in Africa: the moderating role of financial development

PurposeThe purpose of this study is to assess the extent to which the nexus between foreign bank presence (FBP) and inclusive growth is being impacted by the financial development.Design/methodology/approachThe study used a two-stage system generalized method of moment (GMM), using 28 African countries from the period 2000 to 2018.FindingsThe study found a positive effect of FBP on inclusive growth. While financial development magnifies the positive effect of FBP, inclusive growth nexus, it has a direct effect on inclusive growth.Practical implicationsFor Africa to ascertain the positive effect of FBP on inclusive growth, financial system must be developed to reduce the cream-skim behavior of foreign banks.Originality/valueThis paper assess the extent to which developing economy's developed financial system form synergies with FBP to further enhance the inclusiveness of growth.

Pyrolysis of model plastic component polypropylene to hydrogen over mesoporous alumina catalysts: Effect of pluronic structure directing agents

Catalytic pyrolysis of the large and complex polymeric structure of plastic to gaseous fuel has been investigated in this work. A two-stage pyrolytic system is reported for cracking model waste plastic, polypropylene, over mesoporous alumina catalyst to produce H2 and CH4. The experiments have been conducted in the temperature range of 750–900 °C and various catalyst-to-plastic ratios under atmospheric pressure. The alumina-based catalysts were synthesized via the one-pot evaporation-induced self-assembly (EISA) method using four different structure-directing agents (SDA) namely PEG-1000, PEG-4000, P123, and F127 to understand the effect on catalytic properties and performance evaluation. Results revealed that the structured directing agents improve the catalyst's surface properties and affect the product yield. All synthesized catalysts were characterized for crystallinity, topography, and surface properties using X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET), Pyridine-Transmission Fourier transform infrared (Py-FTIR) spectroscopy, and atomic force microscopy (AFM) analysis. A significant effect of SDA was observed on the surface area of the synthesized mesoporous alumina (SMA) catalyst. The decreasing order in terms of the surface area of the SMA is SMAF127 >SMAP40 >SMAP123 >SMAP10> Alumina (without SDA). Approximately, a tenfold increase in surface area was observed with SMAF127 (mesoporous alumina) compared to non-mesoporous alumina. A maximum yield of hydrogen∼40.79 mmol/gram polypropylene was obtained with a catalyst-plastic (C/P) ratio of 1:2.5 at a temperature of 900 °C using SMAF127 owing to its high surface area, and other physiochemical properties.

A sustainable integrated anoxic/aerobic bio-contactor process for simultaneously in-situ deodorization and pollutants removal from decentralized domestic sewage

The integration of anoxic filter and aerobic rotating biological contactor shows promise in treating rural domestic sewage. It offers high efficiency, low sludge production, and strong shock resistance. However, further optimization is needed for odor control, pollutant removal, and power consumption. In this study, the investigation on a one-pump-drive lab-scale device of retention anoxic filter (RAF) integrated with hydraulic rotating bio-contactor (HRBC) and its optimal operation mode were conducted. During the 50-day operation, optimal operation parameters were investigated. These parameters included a 175 % reflux ratio (RR), 5-h hydraulic retention time in the RAF (HRTRAF), and 2.5-h hydraulic retention time in the HRBC (HRTHRBC). Those conditions characterized a micro-aerobic environment (DO: 0.6–0.8 mg/L) in RAF, inducing improved deodorization (89.3 % sulfide removal) and denitrification (85.9 % nitrate removal) simultaneously. During the operation period, 84.79 ± 3.87 % COD, 82.71± 2.06 % NH4+-N, 74.83 ± 2.06 % TN, 91.68± 2.12 % S2−, and 89.04 ± 1.68 % TON were removed in RAF-HRBC. Based on large amount of operational data, organic loading rate curves of RAF-HRBC were validated and calibrated as a crucial reference to aid in full-scale designs and applications. The richness of microbial community was improved in both RAF and HRBC. In the RAF, the autotrophic sulfide-oxidizing nitrate-reducing bacteria (a-son) and heterotrophic sulfide-oxidizing nitrate-reducing bacteria (h-son) were selectively enriched, which intensified the sulfide removal and denitrification process. In the two-stage HRBC system, the 1st stage RBC was primarily composed of organics degraders, while the 2nd stage RBC consisted mainly of ammonium oxidizers. Overall, the integrated RAF-HRBC process holds significant potential for simultaneously improving pollutant removal and in-situ odor mitigation in decentralized domestic sewage treatment. This process specifically contributes to enhancing environmental sustainability and operational efficiency.

Intelligent Controller Based on Artificial Neural Network and INC Based MPPT for Grid Integrated Solar PV System

Solar photovoltaic (PV) systems have become an integral part of today's advanced energy infrastructure due to its low kinetic energy, its abundance availability, and its freedom from human interference. Solar PV systems have the potential to greatly reduce our reliance on fossil fuels, but their intermittent nature means they cannot provide a constant source of electricity. The system's security should be well thought out, and it should be able to withstand a lot of abuse. The current energy system faces a significant difficulty in ensuring continuous supply. In this study, a three-phase, two-stage photovoltaic system that is managed by artificial neural networks (ANN). A DC-DC boost converter with maximum power point tracking (MPPT) based on the incremental conductance (INC) method is incorporated in the first stage. In the next step, an ANN-based controller optimizes the performance of a three-phase switching PWM inverter that is connected to the grid by controlling currents along the d-q axis. Comprehensive simulations were carried out using MATLAB or Simulink to evaluate the system's performance under various illumination and temperature conditions. Results show that the suggested approach outperforms the baseline in a number of areas. Better dynamic reactions, accurate tracking of reference currents within permissible bounds, and quick settling periods after startup are all displayed by it. These findings show that our method has the potential to greatly improve the efficiency and dependability of solar PV systems. The results of this study have implications for renewable energy in general and present a viable path toward enhancing the resilience and sustainability of energy infrastructure.

Changes in the prokaryotic communities occurring along a two-stage anaerobic digestion system treating the organic fraction of solid waste

Two-stage anaerobic digestion is useful for recycling of the organic fraction of municipal solid waste and wastewater; the prokaryotic communities involved in this process were characterized using massive sequencing of 16S rRNA gene amplicons. During the 60-day study the prokaryotic communities were stable in time but were affected by their position in the system. The first stage of solid waste digestion was operated in an anaerobic-hydrolytic leach bead reactor with high organic solids content, the microbial communities were dominated by members of the orders Bacteroidales (62%), Selenomonadales (15%), Lactobacillales (13%), Clostridiales (4%) and Rhodospirillales (1%). At this stage, a vertical stratification acted as a transition zone from aerobic to anaerobic environments modifying significantly the composition and structure of bacterial communities.The second stage occurred in an up-flow anaerobic sludge bed reactor specialized in acidogenesis-methanogenesis, where the leachate of the first stage was co-fed with municipal wastewater. In this stage, the bacterial community was dominated by members of the orders Pseudomonadales, Clostridiales, Burkholderiales, Bacteroidales and Syntrophobacterales (accounting for 52%), while the most abundant orders of the archaeal community corresponded to Methanosarcinales (72%) and Methanobacteriales (13%), both of them with methanogenic capacity.

Proposing of a novel PV/T module in series with a ST+TE module to pursue a round-the-clock continuous energy output

As is well known, traditional solar systems can only work under conditions of solar radiation, as solar energy is the sole energy source for photovoltaic generation and heat recovery. Few studies have focused on their continuous operation throughout the day and this research gap needs to be filled. Consequently, to pursue a round-the-clock electrical power generator, in this study, a two-stage system is constructed, consisting of the first-stage photovoltaic/thermal module and the second-stage solar thermal collector with thermoelectric generators in series. Thermoelectric generators ensure that the system runs normally by day, while also utilizing the heated fluid to achieve uninterrupted energy output at night. A numerical model of the system is developed to analyze the performance changes under continuous running. From the results, the second-stage module improves the daytime heat gain, effectively boosting the electrical contribution of thermoelectric generators, whether during the day or night. At the maximum input energy, photovoltaic cells generate the greatest power of 118.37 W with an average efficiency of 14.56%. The average efficiencies of thermoelectric generators in the daytime and nighttime are 0.97% and 0.53%, enhancing the total electrical output. Additionally, the comparative analysis is performed under different parameters, as well as an economic analysis.

Location–allocation problem for green efficient two-stage vehicle-based logistics system: A type-2 neutrosophic multi-objective modeling approach

In recent decades, global climate change has become one of the most critical environmental issues, leading to increased environmental and social concerns about the sustainability of logistics networks. This study proposes a novel multi-objective, multi-facility location–allocation model for a two-stage solid logistics network that supports green practices. To account for uncertainty in real-world problems, some parameters of the model are represented as triangular type-2 neutrosophic numbers to deal with hesitant situations. The fuzzy model is then converted into a deterministic one using a new ranking approach. Three conflicting objective functions – minimizing total financial costs, maximizing customers’ satisfaction levels, and ensuring sustainable and effective conveyances – are simultaneously optimized using the ϵ-constraint approach. The proposed model and solution approach are tested with two numerical examples. A comparative study is also presented, comparing the proposed approach with other Pareto-based multi-objective approaches, such as the global criterion approach, multi-objective fuzzy programming, and weighted Chebychev programming. Finally, the paper concludes with some remarks.

Performance analysis of a two-stage vapor compression heat pump based on intercooling effect

The two-stage compression technology based on intercooling effect effectively improves the low-temperature adaptability of vapor compression heat pump systems. When a two-stage compression system is applied to address a spectrum of low-temperature operating conditions, obvious variations in the capacity ratio and interrelationship between the two compressors will take place, which may result in an instability of system control and compressor burnout during actual equipment operation. Therefore, to refine the control strategy and enhance the practicality of the two-stage compression system, this study mainly focuses on the investigation of the subcooling (SC) parameter and the desuperheating (SH) parameter during the injection process. Both simulation models and experimental testing platform of a two-stage compression heat pump system with a subcooler structure are conducted to explore the effects of intercooling effect under variable operating conditions on various system performance parameters. The results show that as the injection ratio Rinj increases, the changes of SC and SH, ΔTSC and ΔTSH show a parallelogram-like variation, and the turning point of the variation trend is around Rinj = 0.14, stabilized at about 21.55 °C; ΔTSH first increased slowly from 0 °C to 6.04 °C and then rapidly increased to 33.55 °C; the system heat production Qhot and COP were closely related to the change of SC, but not sensitive to the change of SH. Besides, the optimal intermediate pressure calculation equations are determined for different evaporation temperatures, condensing temperatures and cylinder capacity ratios. This study may offer valuable guidance for improving the throttling valve and compressor capacity control strategies in two-stage compression systems.

A two-stage decision-support system for floating debris collection in reservoir areas

The accumulation of floating debris is one of the main challenges of water conservancy projects, which may pollute the vulnerable ecosystem of the reservoir area and impose significant risks on waterway transportation and dam operations. Due to the dynamicity and uncertainty caused by water flow, the collection of floating debris is much more complicated than on-land waste collection. In this paper, we propose a two-stage decision-support system to optimize the task allocation and routing decisions for floating debris collection in the reservoir area, where the first stage is proactive planning based on historical/observed data and the second stage is reactive planning based on real-time data. The primary objective is to minimize the total collection cost while simultaneously ensuring the accumulation areas with high risks are prioritized in the daily collection plan, and both genetic algorithm and simulated annealing algorithm are used to solve the optimization problems. The proposed method is validated with a real-world case study at Wushan County in the Three Gorges Reservoir area. The computational results show that the level of time-dependent penalty cost on service priority, the types of collection ships, and the number and locations of unloading points are important influencing factors to the cost and responsiveness. Furthermore, the proposed two-stage decision-support system can help effectively optimize the operational planning of floating debris collection in reservoir areas.

Application of Anaerobic-Aerobic Combined Bioreactor in Phosphorus Removal

A two-stage anaerobic-aerobic sequencing reactor system was developed in order to enhance the removal of biological phosphorus in the sequencing of combined reactors. Combining both aerobic and anaerobic designs in one reactor improved the efficiency and reduced the construction and operating costs. The combination of an upflow anaerobic fixed bed (UAFB) and a floating activated sludge aerobic bioreactor was designed with respective Kaldnes packing ratios of 90 and 30% for the anaerobic and aerobic sections. The controlled parameters were pH levels within a neutral range, a temperature of 37°C, mixed liquor suspended solids (MLSS) of 1220 and 1030 mg/L for the aerobic and anaerobic sections, respectively, and an attached growth that was equal of 743 and 1190 mg/L for the aerobic and anaerobic sections, respectively. Tests were conducted for three different initial phosphorus concentrations (12.8, 32.0, and 44.8 mg/L), two different volumes for each section, and four chemical oxygen demands (CODs) (500, 1000, 1200, and 1400 mg/L). The results demonstrated that, generally, the phosphorus removal in the anaerobic section fell significantly by increasing the inlet COD, and the maximum removal occurred at COD = 500 mg/L. More than 90% of the phosphorus was removed in the aerobic section at COD = 500 mg/L. In other words, the best performance of the reactor was when the ratio of the COD : N : P = 100 : 5 : 2, composition of phosphorus in industrial wastewater.

Characterization of a novel two-stage high ash coal gasifier for low tar and high calorific value gas

The high ash content of coal poses two critical challenges in conventional gasifiers: (a) ash agglomeration and (b) low-quality syngas. The ash agglomerations are caused by the interaction of alkali and alkaline earth metals with other inorganic compounds, localized temperature generation, and unoptimized process parameters. Whereas low-quality gas is due to moderate temperature operations and the mixing of syngas with pyrolysis products. Recognizing these challenges, the current work discusses the design, development, and performance characterization of a novel two-stage gasification system that strategically segregates oxidative pyrolysis in a cyclone reactor and oxy-steam char gasification in a packed bed reactor. Such segregation provides explicit control over parameters like local temperatures, particle and gas residence time, enabling the configuration to handle coal with a wide range of ash content. Thermodynamic analysis and performance characterization experiments have been carried out with varied temperatures, oxygen, and steam flow rates. While operating the system up to 950˚C, there was no indication of clinker formation. The gravimetric tar content was found 52 ± 3 mg/Nm3. The concentration of CO, CO2, CH4, and H2 in the product gas during experiments was 40 ± 5, 20 ± 5, 2 ± 1, and 45 ± 5%, respectively. The carbon conversion was greater than 77%, with further scope for improvement.

Integrated production of hydrogen and methane in a dairy biorefinery using anaerobic digestion: Scale-up, economic and risk analyses

Anaerobic digestion has emerged as the most appealing waste management strategy in biorefineries. Particularly, recent studies have highlighted the energy advantages of waste co-digestion in industrial biorefineries and the use of two-stage systems. However, there are some concerns about moving the system from laboratory testing to industrial scale. One of them is the high level of investment that is required. Therefore, this study carried out a techno-economic analysis (scale-up and energy production, economic and risk analysis, and factorial design) to assess the feasibility of single- and two-stage systems in the treatment of cheese whey and glycerin for the production of hydrogen and methane. Scenarios (S1 to S9) considered thermophilic and mesophilic single and two-stage systems with different applied organic loading rates (OLRA). The analyses of scale-up and energy production revealed that S3 (a thermophilic single-stage system operated at high OLRA 17.3 kg-COD.m−3.d−1) and S9 (a thermophilic-mesophilic two-stage system operated at high OLRA 134.8 kg-COD.m−3.d−1 and 20.5 kg-COD.m−3.d−1, respectively) were more compact and required lower initial investment compared to other scenarios. The risk analysis performed by a Monte Carlo simulation showed low investment risks (10 and 11%) for S3 and S9, respectively, being the electricity sales price, the key determining factor to define whether the project in the baseline scenario will result in profit or loss. Lastly, the factorial design revealed that while the net present value (NPV) is positively impacted by rising inflation and electricity sales price, it is negatively impacted by rising capitalization rate. Such assessments assist in making decisions regarding which system can be fully implemented, the best market circumstances for the investment, and how market changes may favorably or unfavorably affect the NPV and the internal rate of return (IRR).

Determinants of non-performing loans in conventional and Islamic banks: Emerging market evidence

This study examines the determinants of non-performing loans (NPLs) among macroeconomic and bank-specific factors for the Islamic and conventional banking sectors in Bangladesh. We implement a dynamic panel data model with a two-stage system GMM for the period 2010-2021. Among the bank-specific factors, this study finds that return on assets, return on equity, bank size, and inefficiency help to reduce NPLs. In contrast, gross loan growth, leverage, and capital adequacy ratios contribute to increasing NPLs. Among macroeconomic determinants, inflation, and GDP growth have a significant negative impact on NPLs. Moreover, unemployment and exchange rates are also found to be significant determinants of NPLs. At the bank level, growth in gross loans reduces NPLs in Islamic banks, while the opposite is true for conventional banks. Our findings have significant implications for depositors and regulators in making appropriate decisions.

Thermodynamic analysis of isothermal compressed air energy storage system with droplets injection

Compressed air energy storage (CAES) is regarded as an effective long-duration energy storage technology to support the high penetration of renewable energy in the gird. Many types of CAES technologies are developed. The isothermal CAES (I-CAES) shows relatively high round-trip efficiency and energy density potentially. The isothermal processes of compression and expansion are realized by injecting water droplets into the compressor/expander cylinders. The compression heat is absorbed to abate temperature increase, and extra heat is added to abate temperature decrease during expansion. Firstly, the thermodynamic model of the I-CAES system using droplet injection method was established, and the calculation formula of droplet mass with rotation angle and air quality was given. The simulation modelling was verified by experimental results. The effects of gas-liquid mass ratio (ML) and rotation speed on thermodynamic performances including isothermal compression/expansion efficiency, isothermality, round-trip efficiency and energy density were studied. Results showed that isothermal compression/expansion efficiency, round-trip efficiency and isothermality were increased by increasing ML and reducing rotation speed, while, ML had the more obvious influence. When charging time was 6 h, discharging time was 4 h and ML equaled 10, round-trip efficiency of the one-stage I-CAES system was 83.15 % and energy density was 1.94 MJ/m3. Round-trip efficiency of the two-stage I-CAES system was 82.53 % and the energy density was 39.93 MJ/m3 under the same conditions.

Design and Building of a Two-Stage Cascade Refrigeration System for Storage of Blood Plasma

Daily life-saving transfusions rely on the usage of blood products in clinical and research settings. With its proteins used for replacement treatment, human blood plasma serves as the main source for a variety of therapeutic transfusions. During the COVID-19 pandemic, plasma-based therapy was one of the treatment modalities used to treat infectious infections and as a source of neutralizing antibodies in patients. The specialty of transfusion medicine was adversely impacted and faced a stockpile shortage because plasma must be quickly frozen within six hours of collection in order for its proteins and coagulation components to be of the optimum quality. As a result, the cascade refrigeration system is an innovative technology that can provide the required ultra-low freezing temperature and maintain the same temperature in storage for plasma management. The paper concentrated on the design and construction analysis of a two-stage cascade refrigeration system for quick freezing time, and storing plasma proteins at extremely low temperatures to prolong their limited shelf life in a sensitive, temperature-controlled storage system. The choice of refrigerants R404A and R410A is made for high temperature and low temperature circuits which are carefully selected based on study and analysis of the characteristics of different refrigerants for short-term freezing. The ultra-low temperature evaporator is achieved using a blend of two vapour compression refrigeration cycles thermally connected by a heat exchanger to produce a freezing temperature of -35 0C. For analysis, the system was charged with various weights of plasma weighing between 1 kg and 4 kg for two hours and a half hour and kept at a temperature of -35 0C. The system's dependability and practicality for extending plasma shelf life were assessed. After 72 hours of temperature-controlled storage, the results showed 75% efficiency and a negligible (0.4) plasma quality drop.

Achieving intensified nitrogen removal and vivianite recovery from sludge digester liquor in two-stage partial nitrification-electrolysis anammox system

Achieving intensified nitrogen removal and vivianite recovery from sludge digester liquor in two-stage partial nitrification-electrolysis anammox system

ARE POLITICAL STABILITY AND DEMOCRACY EFFECTIVE ON FINANCIAL DEVELOPMENT? EVIDENCE FROM SUB-SAHARAN AFRICAN COUNTRIES

The interaction between institutional phenomena such as political stability and democracy and the financial system is an important issue that has been researched for many years. For this reason in this study, the effects of political stability and democracy on the financial system in Sub-Saharan African countries during the period from 2002 to 2019 are investigated. In the study, in which the Two-Stage System Generalized Moments Method estimator is used, the dependent variable is the financial institutions development index. The explanatory variables of the study are the indicators of political stability and democracy. The growth in GDP per capita, trade openness, inflation rate, foreign direct investment and urban population ratio are the control variables. The analyzes display that democracy and political stability have positive effects on financial development. In terms of control variables, while the inflation rate has a negative effect on financial development, the economic growth and trade openness affect financial development positively.

Overexpression of BAPT and DBTNBT genes in Taxus baccatain vitro cultures to enhance the biotechnological production of paclitaxel.

Paclitaxel is one of the most effective anticancer drugs ever developed. Although the most sustainable approach to its production is provided by plant cell cultures, the yield is limited by bottleneck enzymes in the taxane biosynthetic pathway: baccatin-aminophenylpropanoyl-13-O-transferase (BAPT) and 3'-N-debenzoyltaxol N-benzoyltransferase (DBTNBT). With the aim of enhancing paclitaxel production by overcoming this bottleneck, we obtained distinct lines of Taxus baccata in vitro roots, each independently overexpressing either of the two flux-limiting genes, BAPT or DBTNBT, through a Rhizobium rhizogenes A4-mediated transformation. Due to the slow growth rate of the transgenic Taxus roots, they were dedifferentiated to obtain callus lines and establish cell suspensions. The transgenic cells were cultured in a two-stage system and stimulated for taxane production by a dual elicitation treatment with 1 μm coronatine plus 50 mm of randomly methylated-β-cyclodextrins. A high overexpression of BAPT (59.72-fold higher at 48 h) and DBTNBT (61.93-fold higher at 72 h) genes was observed in the transgenic cell cultures, as well as an improved taxane production. Compared to the wild type line (71.01 mg/L), the DBTNBT line produced more than four times higher amounts of paclitaxel (310 mg/L), while the content of this taxane was almost doubled in the BAPT line (135 mg/L). A transcriptional profiling of taxane biosynthetic genes revealed that GGPPS, TXS and DBAT genes were the most reactive to DBTNBT overexpression and the dual elicitation, their expression increasing gradually and constantly. The same genes exhibited a pattern of isolated peaks of expression in the elicited BAPT-overexpressing line.

Energy, exergy, economic and environmental (4E) analysis of two-stage cascade, Linder-Hampson and reverse Brayton systems in the temperature range from −120 °C to −60 °C

Cryopreservation in the temperature range from −120 °C to −60 °C is an important way to achieve high-quality food storage. In this paper, an in-depth quantitative thermodynamic comparison of two-stage cascade cycle, Linde-Hampson cycle and reverse Brayton cycle was carried out in the temperature range from −120 °C to −60 °C. Aspen HYSYS was used to invoke advanced genetic algorithm in MATLAB to optimize the system parameters. The two-stage cascade system performs best at the evaporation temperatures above −80 °C, achieving a COP of 0.97 at −60 °C. The Linder-Hampson system performs best when the evaporation temperature is below −90 °C, achieving a COP of 0.35 at −120 °C. In order to further explore the impact of environmental change on the system performance, five typical cities in China were selected to analyze the seasonal performances of the three systems. The seasonal analysis demonstrated that Harbin has the highest latitude and its seasonal energy efficiency ratio is significantly higher than other cities, the performance of the two-stage cascade system fluctuates more obvious within 24-h. What's more, the Linder-Hampson system has the lowest annual investment cost and annual operating cost at the evaporation temperature lower than −90 °C, as well as the lowest emissions of CO2 and SO2.