Coefficient Of Performance Improvement Research Articles

Operational performance of PCM embedded radiant chilled ceiling using a rule-based control strategy

The increasing energy demand for space cooling, projected to triple by mid-century and surpassing a quarter of today's global electricity usage, underscores the urgent need for innovative, more energy-efficient air-conditioning technologies. The research introduces phase change material (PCM) embedded radiant cooling (PCM-RCC) as a promising solution, offering enhanced energy efficiency and indoor environmental quality. Despite its potential, PCM-RCC remains in the developmental stage, requiring further research to fully unlock its benefits. This work aims to analyse the operational performance of PCM-RCC and develop an advanced rule-based control strategy to enhance its efficiency further. The analysis was conducted using a validated PCM-RCC transient system simulation model. To quantify the advantages of PCM-RCC over typical radiant cooling and evaluate the effectiveness of the proposed control strategy, two reference cases are defined: (1) basic-controlled PCM-RCC, and (2) radiant cooling without PCM. Results reveal that PCM-RCC with advanced control demonstrates higher load flexibility (∼93% off-peak time operation), 12% less electricity usage, a 5% coefficient of performance improvement, and a 30% decrease in operational costs compared to radiant cooling. Furthermore, the proposed system shows 9% lower energy usage with a 20% improvement in thermal comfort compared to basic-controlled PCM-RCC.

Thermodynamic and economic analyses of modified ejector enhanced solar-air composite dual-source heat pump system in residential buildings

This research utilizes an ejector enhanced solar-air composite dual-source heat pump (EDHP) system for water heating in residential buildings. The main advantage of the EDHP system is the use of an ejector and dual-heat source to efficiently utilize solar energy, thereby enhancing heating performance. This ejector operates by utilizing a refrigerant stream from the solar collector line with higher pressure to elevate the suction pressure of the compressor. This feature enables the EDHP system to maintain stable heating performance even in adverse weather scenarios with low temperatures or limited solar radiation. Thermodynamic modeling using energetic and exergetic analysis methods is employed to theoretically evaluate the conventional air-source heat pump and EDHP systems. The energy analysis of the EDHP system using R134a refrigerant has shown significant improvements in both heating coefficient of performance (COP) and exergy performance (ECOP). Under specific conditions, such as an ambient temperature of −5 °C and an irradiance level of 250 W∙m2, and utilizing a 20 m2 PVT (Photovoltaic and Thermal) collector for a heating supply of 5 kW, the EDHP system exhibits a 23.64 % increase in COP and a 25.83 % increase in ECOP. Furthermore, when the electricity generated by the PV system is incorporated into the EDHP system, the demand for electricity from the grid can be reduced by up to 51.96 % under the same conditions. In the Beijing area and considering the current energy price system, the heating operating cost of the EDHP system is 0.206 Yuan/kWh. Compared to a standard air-source heat pump system, the payback period for EDHP system ranges approximately from 10 to 12 years, taking into account an annual heating period of 5 months. Among the alternative refrigerants to R134a in the EDHP system, R152a is found to be the most suitable. It shows COP improvements of 24.92 %–30.0 % and ECOP improvements of 24.89 %–29.96 %. This innovative approach opens up new possibilities for the application of heat pump technology under adverse weather conditions in residential and commercial buildings.

Study of an integrated vortex tube used in hydrogen pre-cooling system

In hydrogen refueling stations, a hydrogen pre-cooling system is essential to protect the onboard hydrogen storage cylinder from high-temperature damage during refueling. To address the high power consumption of existing systems, this study proposes an integrated vortex tube hydrogen pre-cooling system. This system combines the vortex tube with a two-stage compression refrigeration cycle to create a new refrigeration device. The vortex tube component is numerically simulated using the standard k-ε turbulence model. Comparative analysis of power consumption and coefficient of performance (COP) is conducted between the new system, single-stage, and two-stage hydrogen pre-cooling systems. The results indicate that the vortex tube, as the pressure ratio increases from 1.5 to 20, reduces power consumption by 26.37%–41.52% compared to the single-stage system. Additionally, it improves the COP by 30.9%–53.8% compared to the single-stage system. Furthermore, compared to the two-stage system, the vortex tube achieves power savings of 4.08%–10.44% and COP improvements of 4.3%–11.7%.

Utilizing Renewable Energy Sources for Sustainable Air Conditioning and Refrigeration

This study delves into the transformative potential of integrating renewable energy sources to enhance sustainability in air conditioning and refrigeration systems. By employing a mixed-methods approach, combining quantitative data analysis and qualitative insights, this research investigates the impact of renewable energy integration. Quantitative results from 40 participant systems reveal a significant 25% reduction in energy consumption during peak hours, showcasing the potential for load management and grid stress alleviation. Furthermore, systems integrated with renewable sources exhibit an average 15% improvement in Coefficient of Performance (COP), underscoring heightened operational efficiency. Additionally, these systems derive 30% of their total energy consumption from renewable sources, underpinning their substantial contribution to sustainable power generation. Qualitative insights echo these findings, emphasizing user satisfaction, cost savings, and environmental consciousness. Despite concerns about initial investment costs and system reliability, the results collectively underscore the transformative potential of renewable energy integration in fostering energy efficiency and sustainability within these critical sectors. This study advocates for ongoing research and collaboration to fully realize the benefits of renewable energy solutions in air conditioning and refrigeration practices

Performance analysis of a double-efficient CO2 cooling and heating system using an ejector

This paper presents a double-efficient CO2 cooling and heating system using an ejector, which can operate as modified dual-evaporators ejector expansion cycle (MDEEC) in cooling mode or as conventional heat pump cycle (CHPC) in heating mode through the reasonable arrangement of valves, and countercurrent heat transfer of CO2 with cooled or heated air is achieved in both modes. An ejector is utilized to recover the expansion work and two evaporators provide independent air dry-cooling and dehumidification in cooling mode. Two thermodynamic models are developed to investigate the effects of various parameters on the cycle performance. Comparison of proposed cycles with ejector expansion refrigeration cycle (EERC) and conventional dual-evaporator vapor compression cycle (CDVCC) are conducted based on energy analysis. The results show that coefficient of performance (COP) of this system is improved by more than 25% compared to EERC, and 33.62–56.27% compared to CDVCC. Besides, performance comparison of CHPC using CO2 and R134a is conducted, which reveals that COP of CO2 cycle is consistently higher, maintained above 2.7, and the maximum value is 5.36. The COP improvement is up to 29.74%, and the minimum value is 5.37%. This study provides a solution for efficient cooling and heating applying CO2 as refrigerant.

Design for Improvement of COP from Waste Heat Utilization Through Air Conditioning System

Energy is in higher demand than ever before since there are an increasing number of applications for it; nevertheless, the existing sources are unable to supply it in sufficient quantities. Alternate energy sources should be utilized, and as a consequence, energy conservation should be achieved through the utilization of waste heat from air conditioning systems. The major objective of this piece is to make use of waste heat generated by residential air conditioning systems while simultaneously increasing the coefficient of performance (COP). In order to achieve this goal, an experimental setup is utilized. In this configuration, an indirect kind of heat recovery equipment is used, and a heat exchanger that converts heat from a refrigerant to water is positioned between the compressor and the condenser of the host refrigeration system. The hot refrigerant gas generated by the compressor is sent via one side of the heat exchanger, while water is forced through the other side. The temperature of the water is raised as a result of the heated refrigerant gas. Because of this, the system’s COP might potentially increase by up to 16%.

Performance comparison and characterization of multi-pressure vapor compression systems at optimized conditions for simultaneous cooling and heating application

We performed numerical thermodynamic analyses of 3 multi-pressure vapor compression system configurations (cascaded, with flash tank, and with ejector) to evaluate their coefficient of performance improvements in combined cooling and heating applications. Six refrigerants were evaluated, and 25 temperature pairs of −15 °C to 25 °C cooling and 45 °C to 85 °C heating were specified. Critical parameters of the 3 configurations were varied for performance optimization. The compressor outlet temperature was constrained to prevent lubricant breakdown in actual implementation. Maximum performance improvements of 34.41 %, 39.20 %, and 46.34 % for the cascade, with flash tank, and with ejector systems, respectively, were attained. Moreover, the total number of temperature pairs exceeding the temperature limit was reduced from 19/25 to 17/25, 1/25, and 9/25 for the cascade, with flash tank, and with ejector systems, respectively. The best refrigerants to use were found to be Ammonia or R245fa as the low-pressure loop refrigerant with R245fa as the high-pressure loop refrigerant for cascade systems, Ammonia or R245fa for systems with flash tank, and R245fa for systems with ejector. This work demonstrated and quantified the ability of multi pressure configurations to increase the performance of vapor compression systems in simultaneous cooling and heating applications.

Thermoelectric cooler (TEC) based thermal control system for space applications: Numerical study

The present study devises and numerically investigates a new thermal control system for detectors of optical payloads for spacecraft systems. The system uses thermoelectric coolers (TECs) as the active element which maintains the cold finger at the required set point such that temperature of detectors is maintained within the required range throughout its operation. The system doesn’t utilize any heat pipe network, but instead, uses radiators attached to the hot-side of TEC to dissipate the heat load into the ambient space environment. System level modelling using effective properties are used to model the performance of TEC without modelling any internal intricate geometry. Temperature dependent current profiles are used as input conditions for the TECs such that the TEC consume only the required amount of external power. Effect of TEC set point and geometrical parameters of the radiator is studied and it is observed that considerable reduction in power consumption or improvement in coefficient of performance is obtained by utilizing a larger set point or a radiator with larger dimensions. The system is further investigated for different heat loads and duty cycles (upto 50% for an orbit period of 100 mins) to evaluate its efficacy under varying operating conditions. The system is also investigated for successive operating cycles and it is observed that the cyclic error between successive cycles eventually diminishes to zero thus implying that the temperature control requirements are met for successive cycles throughout the life of the system.

Effects of absorption pressure and temperature on NH3-H2O-LiBr-TiO2 nanofluid absorption performance and system COP

Adding nanoparticles can enhance the mass and heat transfer of basic fluid, improving the coefficient of performance(COP) of the absorption refrigeration system(ARS). However, there are few experimental studies on the effects of absorption pressure and temperature on the absorption performance of nanofluid in an actual ARS. Therefore, the TiO2 nanoparticles are added to the NH3 - H2O – LiBr working fluid. The difference in ammonia mass fraction between the inlet and outlet solution of the absorber (Δε'a) is compared with when the solution is absorbed saturated (Δεa). The results indicate that the Δε'a and system COP increase when the absorption temperature decreases, the absorption pressure increases, or the TiO2 mass fraction increases. The ratio Δε'a/Δεa is used to evaluate the absorption efficiency of the nanofluid. The positive effects of nanofluid on the absorption efficiency and COP slightly increase when absorption temperature increases, but decrease when the absorption pressure is greater than 0.31 MPa. For all of our test groups, the greatest improvement in absorption efficiency is 85 %, and the largest improvement in COP is 13.7 %.

Effect of an Internal Heat Exchanger on the Performances of a Double Evaporator Ejector Refrigeration Cycle

A theoretical investigation is presented about a double evaporator ejector refrigeration cycle (DEERC). Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by an internal heat exchanger (IHX). The ejector is introduced into the baseline cycle in order to mitigate the throttling process losses and increase the compressor suction pressure. Moreover, the IHX has the structure of a concentric counter-flow type heat exchanger and is intentionally used to ensure that the fluid at the compressor inlet is vapor. To assess accurately the influence of the IHX on the DEERC performance, a mathematical model is derived in the frame of the dominant one-dimensional theory for ejectors. The model also accounts for the friction effect in the ejector mixing section. The equations of this model are solved using an Engineering Equation Solver (EES) for different fluids. These are: R134a as baseline fluid and other environment friendly refrigerants used for comparison, namely, R1234yf, R1234ze, R600, R600a, R290, R717 and R1270. The simulation results show that the DEERC with an IHX can achieve COP (the coefficient of performance) improvements from 5.2 until 10%.

Performance improvement potential of a PV/T integrated dual-source heat pump unit with a pressure booster ejector

• Ejector enhanced PV/T air dual-source heat pump is presented. • Optimum PV/T evaporation temperature is determined. • The COP of the heat pump can be improved by 22.6% when 15 m 2 PV/T collector is used. • Consumed electricity from the grid for heating can be reduced by 75% when 15 m 2 PV/T collector is used. Dual-source heat pump unit can utilize the evaporation of the refrigerant at two different pressures. By adopting an ejector, high-pressure refrigerant stream can be used to lift compressor inlet pressure which results in a higher coefficient of performance (COP). This study proposes a renewable energy sourced and high-efficiency heat pump system which can be easily building integrated to offer a renewable heating solution. The system is devised on the complementation of dual thermal sources; one is air and the other one is solar, to maximize the utilization of ambient energy for highly efficient operation of heat pump. Using the advantage of the relatively lower operating temperature in the solar collector line, the thermal efficiency of the collector would be sufficient in winter. Adaptation of photovoltaics in the collector as a PV/T unit, will benefit the system from the produced electricity for further reduction of the demand from the grid. Along with the use of PV/T collector, the system can be potentially carbon neutral for larger collector areas. In this study, the performance improvement potential of a dual-sourced heat pump unit with an ejector as a booster is investigated for different locations in Turkey which presents different solar and weather profiles. The optimum collector evaporation temperatures are determined, and COP improvement potentials are discussed for different conditions. For a heating supply of 5 kW, the COP of the system can be improved by 22.6% under 400 W/m 2 and 10°C ambient using 15 m 2 PV/T collector. Including the electricity generated from the PV, reduction of the electricity demand from the grid can reach to 75% for the same conditions.

Experimental study on energy, exergy, and exergoeconomic analyses of a novel compression/ejector transcritical CO2 heat pump system with dual heat sources

A novel compression/ejection transcritical CO2 heat pump system with dual heat sources (CHP) was proposed in our previous research. This paper experimentally investigates the feasibility and performance of the novel system and compares it with the conventional transcritical CO2 heat pump system (THP). The experimental results show that the maximum heating capacity and outlet water temperature can reach 50.49 kW and 85.8℃; The maximum exergy destruction of the novel system at 20 Hz to 30 Hz occurs in the gas cooler, which varies from 701.05 W to 1335.47 W, but the maximum exergy destruction at 35 Hz is the compressor, which is 1824.21 W; The total exergy cost rate of the throttle valve plays a dominant role in the system operation. In addition, the coefficient of performance (COP) and the exergy efficiency (ηEX) of the CHP are higher than that of the THP; The COP, ηEX, and IREX improvements of the CHP over the THP at the optimum discharge pressure, and the maximum improvements accordingly are 14.83 %, 38.14 %, 10.26 %, respectively. It can be concluded that the novel system is feasible and superior to the THP system. The research results will help to further promote the research and application of air source heat pumps integrating solar energy or geothermal energy due to the addition of the water source evaporator.

Optimized thermal management of a battery energy-storage system (BESS) inspired by air-cooling inefficiency factor of data centers

Inspired by the ventilation system of data centers, we demonstrated a solution to improve the airflow distribution of a battery energy-storage system (BESS) that can significantly expedite the design and optimization iteration compared to the existing process. A defective cooling system of a BESS decreases the overall operational efficiency and increases the risk of thermal runaway, but current design optimizations rely on a case-by-case approach. The solutions of this fashion are both time-consuming and costly because of the laborious recursive process. The desire to eliminate the time for development motivates us to pursue a more general path for design optimization. In this work, we identified the similarity of geometry between the data center and the BESS, as well as the factors that induced the unbalanced airflow distribution. Inspired by the data-center thermal management, we propose a generalized solution of layout arrangement that we applied to the BESS design. We performed a quantitative analysis of cooling performance and investigated the flow patterns under given operating configurations. After modification, the maximum temperature difference of the battery cells drops from 31.2°C to 3.5°C, the average temperature decreases from 30.5°C to 24.7°C, and the coefficient of performance (COP) increases four-fold. The modification shows an improvement in temperature uniformity, overall temperature and COP. The cooling solution applicable to the general container BESS design demonstrates the enormous potential for an effective and rapid design optimization.

Parametric design analysis of a multi-level 3D manifolded microchannel cooler via reduced order numerical modeling

Waste heat flux from power dense electronics is expected to reach > 1 kW/cm2 in the next few decades, and they will require novel cooler designs with low thermal resistance, that can simultaneously dissipate large levels of heat and have high coefficient of performance (COP). 2D straight microchannel cold plates (CP) are an industrial go-to solution for active heat dissipation needs, but they suffer from a major drawback – very high pump pressure is required to force large quantities of fluid through miniscule channels in the CP and thus these coolers are very inefficient, achieving low COP. Recently, manifolded micro-coolers (MMC) have become popular which use a second manifold layer to distribute the fluid in 3D within the CP, thus shortening fluid travel length within the miniscule CP channels and significantly reducing the total device pressure drop. In this study, we first introduce a novel two-level manifold design which boasts a potential of > 2x improvement in COP compared to conventional single-level manifold concept without affecting the thermal performance. Recognizing the difficulty in simulating large area full MMCs, we then aim to simplify the 2-level MMC geometry into reduced order models to bring down simulation cost at an expense of accuracy. Two models were considered, the widely popular and convenient to use Single Cold Plate U-bend Channel (SCPUC) model which only simulates the CP channels, and the slightly more complicated Single Manifold Channel (SMC) model which also considers the effect of the manifold. The SMC model simulations were first validated against full device simulations for different heater footprint sizes (25, 100, 400 mm2) to establish accuracy and it was found that the SMC model could predict thermal performances of all device sizes with a nominal inaccuracy of 5%. In contrast, the widely accepted SCPUC model produced highly inaccurate (as high as 25–45%) predictions for thermal performance of the MMCs. The two models were then used under an extreme heat flux load of 800 W/cm2 and 0.2 liter per min (lpm) device flow rate, to simulate 54 different 2-level MMCs obtained by varying important geometric parameters on the manifold and cold plate side. Detailed analysis was performed to explain the trends in thermal performance and pressure drop with different geometric parameters. Finally, two pareto curves were reported, one between thermal resistance and pressure drop, and the other between COP and device size. It was seen that the proposed 2-level MMC showed record high COP as compared to state-of-the-art single-level MMCs. We hope that this study will act as a design guide for MMCs as well as act as a performance repository for a wide range and combinations of geometries of 2-level manifold structures.

Exergy Efficiency and COP Improvement of a CO2 Transcritical Heat Pump System by Replacing an Expansion Valve with a Tesla Turbine

The heat pump system has been widely used in residential and commercial applications due to its attractive advantages of high energy efficiency, reliability, and environmental impact. The massive exergy loss during the isenthalpic process in the expansion valve is a major drawback of the heat pump system. Therefore, the Tesla turbine exergy analysis in terms of transiting exergy efficiency is investigated and integrated with the transcritical heat pump system. The aim is to investigate the factors that reduce exergy losses and increase the coefficient of performance and exergy efficiency. The contribution of this paper is twofold. First, a three-dimensional numerical analysis of the supercritical CO2 flow simulation in the Tesla turbine in three different geometries is carried out. Second, the effect of the Tesla turbine on the coefficient of performance and exergy efficiency of the heat pump system is investigated. The effect of the rotor speed and disk spacing on the Tesla turbine power, exergy loss, and transiting exergy efficiency is investigated. The results showed that at a lower disk spacing, the turbine produces higher specific power and transiting exergy efficiency. In addition, the coefficient of performance (COP) and exergy efficiency improvement in the heat pump system combined with the Tesla turbine are 9.8% and 28.9% higher than in the conventional transcritical heat pump system, respectively.

An effective strategy for decreased energy consumption by using Fe3O4+ CeO2@ POE in Cooling system

With a view to decreasing the energy consumption in cooling systems, many different methods have been used at the present time. One of these methods is the addition of solid nanoparticles to the compressor lubricant in order to increase the heat transfer surface. In this context, single and hybrid nanolubricants have been prepared by adding nano-sized iron (II, III) oxide (Fe3O4) and cerium oxide (CeO2) hybrid nanoparticles into polyol ester (POE) at different mass ratios by weight. 0.3% and 0.6% by weight of single Fe3O4and hybrid Fe3O4+ CeO2nanoparticles were added to this colloidal suspension separately. In addition, a 0.3% volume fraction of the surfactant triton X-100 (TX-100) was added to each suspension to avoid folliculations in nanolubricants. An experimental study was conducted under two different mass fraction single and hybrid nanolubricant to compressor section of the cooling system, respectively. The maximum improvement in coefficient of performance (COP) and the decrease in compressor work were found to be as 11.84% and 16.73%, respectively, when the hybrid nanolubricant was used as compressor lubricant.

Heating and power generation characteristics of the vapor injected photovoltaic-thermal heat pump system

The vapor injection compression cycle has been proved that can effectively improve the heating performance of the photovoltaic-thermal (PVT) heat pump system. In this paper, a simulation model of the vapor injected PVT heat pump system (VI-PVTHP) has been established and verified experimentally. The influence law of environmental parameters on the heating and power generation performance of the VI-PVTHP have been clarified. Results show that the coefficient of performance (COP) of the system would increase by about 0.035 under the water heating condition when the ambient temperature increases by 1 °C, and would increase by about 0.041 under the space heating condition. The COP of the system would increase by 0.12 and 0.15 with an average increase of 100W/m2 of solar irradiance under the water heating condition and space heating condition respectively. Additionally, the heating performance of the VI-PVTHP and the conventional PVT heat pump (employing single stage compression cycle) has been compared. Results show that the heating capacity and COP improvement of the vapor injected PVT heat pump system could be higher than 30% and 15% respectively. And the harsher the ambient condition is, the more obvious the heating performance advantage of the vapor injected PVT heat pump system is.

A novel index model for defrosting initiating time point of air source heat pump based on the cusp catastrophe theory

In winter, the operating performance of air source heat pump (ASHP) units deteriorates due to the accumulation of frost on the outdoor coil surface. In order to reduce the impact of this disaster phenomenon, ensure stable operation and save energy, it is necessary to accurately determine the initiation of defrosting after a period of unit operation. Although some existing defrosting initiation control strategies are effective, too much data volume and accuracy are required. To address these issues, a different perspective on mutation from previous studies is taken. This study combines the cusp catastrophe theory with frost accumulation, and presents a defrosting initiation index model for ASHP. After a brief description of the cusp catastrophe theory, the discriminant index model based on the cusp catastrophe theory (DICC) is proposed, state variable and control variables of the index model are determined. Then, the unit was tested for 10-days. To solve and verify the DICC, 10-days experimental data was used and it was found that DICC can efficiently predict the heating capacity decreases. Consequently, the DICC-based defrosting initiation control strategy was compared with the existing strategies, and the unit’s performance improvement compared to the original strategy was evaluated, as the results show, a 3.9% improvement in coefficient of performance (COP) and a 4.9% increase in heating capacity. Therefore, the strategy proposed in this paper is suitable for ASHP units with limited data capacity and low data accuracy, also can ensure the accurate initiation of defrosting and efficient operation.

Performance improvement of a desiccant based cooling system by mitigation of non-uniform illumination on the coupled low concentrating photovoltaic thermal units

A Low Concentrating Photovoltaic Thermal system typically employs compound parabolic concentrator to focus sunlight and enhance the quality of both thermal and electrical energy extracted. One of the major issues during this process is the introduction of non-uniform illumination on the photovoltaic panels which can cause hot-spots and significantly reduce both the reliability and the electrical output from this system. This non-uniform illumination can be mitigated by integrating homogenizers which are typically linear extensions to the compound parabolic concentrators profile also referred to as elongated compound parabolic concentrators. In this work, the performance of a 2.5× Elongated Compound Parabolic Concentrator truncated to 1.7× and connected to a desiccant based cooling system has been explored. For a detailed analysis of the system, a coupled 3-D optical, electrical, thermal and process efficiency model has been developed. A full-scale prototype of the modelled system is also fabricated using a 380-Watt peak photovoltaic panel. Experiments conducted on the developed system showed a peak outlet water temperature of 56 °C at a mass flowrate of 24 L per hour. Comparative studies between compound parabolic concentrators and elongated compound parabolic concentrators based low concentrating photovoltaic thermal system is also presented to showcase the overall improvement in the process efficiency due to the mitigation of non-uniformity. Using a 400 mm length of the homogenizer the spatial non-uniformity factor was found to drop from 0.5 to 0.29 under normal incidence angle and results in a rise of 12% in the electrical output when compared to a compound parabolic concentrators-based system. The coefficient of performance of the desiccant-based air-cooling system is found to increase by 50% when coupled with two series-connected elongated compound parabolic concentrators based low concentrating photovoltaic thermal system. The improvement in coefficient of performance is mainly because of thermal and electrical energy savings from the developed system amounting to 352 kWhe/year and 665 kWhth/year, respectively. Further, the mitigation of non-uniform illumination showed a performance improvement of 5% in the coefficient of performance of the air-cooling system compared to a compound parabolic concentrators-based system.

Performance Analysis of a Novel Cascade Vapor Compression System for Small-Scale Desalination and Cooling

Abstract The demand for improving living standards has led to increasing freshwater consumption and comfort cooling, requiring significant performance improvements. In this regard, a novel and efficient cascade refrigeration system (CRS) for simultaneous generation of considerable freshwater and cooling effect is proposed. The system does not require dedicated components for desalinating seawater because it is a by-product of the proposed CRS. Utilizing the cascade configuration enhances energy efficiency by lowering the compression work while improving energy recovery by utilizing the heat rejected from the condenser of low-temperature cycle to vaporize seawater for desalination in the evaporator of the high-temperature cycle of the proposed cascade system. A mathematical model of the innovative system based on thermodynamic and economic principles has been developed and utilized to predict the proposed system's thermal performance and cost-savings. A comprehensive analysis has been conducted to study the effect of multiple parameters such as the evaporator, condenser, and brine boiling temperatures. The main studied parameters were coefficient of performance (COP), gain output ratio (GOR), freshwater production, and total cost-savings. For a 10 tons of refrigeration (TR) unit, the freshwater production was between 56.11 and 73.36 kg/h, with cost-savings reaching 2226 US$/year. It was found that the freshwater production increased with condenser and brine boiling temperature but decreased with evaporator temperature. The COP improvement can be as much as 26% over the reference cooling system without desalination.