Thermodynamic relationship of subcooling power and increase of cooling output in vapour compression chiller

Li, Zeyu; Chen, Erjian; Jing, Yue; Lv, Shiliang

doi:10.1016/j.enconman.2017.07.030

Cited by 27 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Meanwhile, the COP of the absorption and hybrid subsystem increases by 11.55% and 9.01%, respectively. Moreover, the heat load of the condenser in the compression subsystem and compressor work is insensitive to the change of the hot water temperature, which is similar to the trend of our previous study [23].…”

Section: Off-design Performancesupporting

confidence: 87%

“…The heat load of the generator and the cooling output of the absorption subsystem and hybrid system rises by 77.15%, 97.63% and 10.07%, respectively, when the inlet temperature of the hot water enhances by 35 • C. Meanwhile, the COP of the absorption and hybrid subsystem increases by 11.55% and 9.01%, respectively. Moreover, the heat load of the condenser in the compression subsystem and compressor work is insensitive to the change of the hot water temperature, which is similar to the trend of our previous study [23].…”

Section: Off-design Performancesupporting

confidence: 87%

“…In general, the validation consists of three sections: (1) characteristic equation of absorption; (2) model of compression subsystem based on the lumped parameter method; and (3) modeling of the hybrid system by coupling the models of both subsystems. Because the model of the compression subsystem has been verified in our study previously [23], two experiments were performed to verify the absorption subsystem and hybrid system models. The first experiment is performed to control the hot water temperature by adjusting the water flow rate of the collector to change the cooling capacity of the absorption subsystem.…”

Section: Model Validationmentioning

confidence: 99%

“…Because the off-design modeling of the SASCHCS relies primarily on the coupling of the cooling output in the absorption subsystem and the thermodynamic characteristics of the compression subsystem component, the iteration can be simplified if the absorption subsystem is treated as a black box and is described by a simple equation that avoids complicated calculations, i.e., the characteristic equation [21] or the empirical expression [22]. Inspired by this idea, we [23] modeled and simulated the hybrid system with some simplifications, in which the absorption subsystem is hypothesized to be a subcooler with fixed subcooling power, and the entire system is equivalent to a vapor compression chiller with a subcooler. It was demonstrated that the solving time reduces significantly and the model converged easily in the overall conditions.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Chen

et al. 2018

Applied Sciences

Self Cite

View full text Add to dashboard Cite

The solar absorption-subcooled compression hybrid cooling system (SASCHCS) is potentially an economical solution for high-rise buildings. The hybrid system is subjected to off-design operation frequently, owing to the changes in solar irradiance and cooling demand. However, a large amount of iterations and difficult convergence are encountered in the traditional off-design modeling. Hence, our present study contributes to the development of an off-design model that is exact and can be solved conveniently. A novel modeling method based on the combination of an absorption subsystem described by the characteristic equation and a compression subsystem modeled by the lumped parameter method is proposed. A prototype and corresponding experimental system are developed to verify the model. A good agreement between the theoretical result and test data is displayed. The maximum deviation is less than 4%. Subsequently, the performance of the facility for different operating conditions is simulated and analyzed. We found that the subcooling power relies significantly on the compressor speed, i.e., a reduction by 58.6% when the compressor speed reduces by 80%. In addition, a high temperature and low flow rate of cooling water in the compression subsystem is adverse to the performance of the hybrid system. Our study can serve as the foundation for the operational analysis of the solar absorption-subcooled compression hybrid cooling system as well as promote its development.

show abstract

Section: Off-design Performancesupporting

confidence: 87%

Section: Off-design Performancesupporting

confidence: 87%

Section: Model Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Chen

et al. 2018

Applied Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, the cooling load is solely covered by compression subsystem when the solar heat is insufficient to drive the absorption subsystem. The conversion of cooling output in the compression subsystem through the subcooling power mainly depends on the flow rate of cooling water and chilled water as well as the compressor speed [22]. It was exhibited that the increase of cooling capacity to the subcooling power is 0.9-1.2 for the fixed superheating by experiment [23].…”

Section: Description Of Saschcsmentioning

confidence: 97%

Performance of Solar Absorption-Subcooled Compression Hybrid Cooling System for Different Flow Rates of Hot Water

Zhang

Jing

et al. 2020

Applied Sciences

Self Cite

View full text Add to dashboard Cite

The solar absorption-subcooled compression hybrid cooling system (SASCHCS) is tech-economically feasible for high-rise buildings. Since such a system operates with no auxiliary heat source, the performance coupling of its absorption subsystem and solar collectors is sensitive to the variation of hot water flow rate. In this regard, the relationship of system performance and hot water flow rate is required to be clarified exactly. Therefore, this paper aims to illustrate the effect mechanism of hot water flow rate and to propose the corresponding decision criterion. The case study is based on a typical high-rise office building in subtropical Guangzhou. The daily working process of this system with different hot water flow rates is simulated and analyzed. Subsequently, the useful heat of collectors and cooling capacity of the absorption subsystem with the hot water flow rate is discussed in detail. The results show that the SASCHCS operates with hot water temperatures ranging from 60 °C to 90 °C. The energy saving increases with the rise of hot water flow rate, but such variation tends to be flat for the excessively high flow rate. As the collector flow rate increases from 1 m3/h to 10 m3/h, the daily energy saving improves by 21% in August. Similarly, the daily energy saving increases by 37.5% as generator hot water flow rate increases from 1 m3/h to 10 m3/h. In addition, the collector flow rate of 3.6 m3/h (13.33 (kg/m2 h)) and the generator flow rate of 5.2 m3/h (19.26 (kg/m2 h)) are optimal for the annual operation, with considering power consumption of water pumps. This paper is helpful for the improvement of SASCHCS operating performance.

show abstract

CO ₂ Subcooling

Llopis

Sánchez

Nebot‐Andrés

et al. 2021

Transcritical CO2 Heat Pump

View full text Add to dashboard Cite

Thermodynamic relationship of subcooling power and increase of cooling output in vapour compression chiller

Cited by 27 publications

References 31 publications

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Performance of Solar Absorption-Subcooled Compression Hybrid Cooling System for Different Flow Rates of Hot Water

CO ₂ Subcooling

Contact Info

Product

Resources

About

Thermodynamic relationship of subcooling power and increase of cooling output in vapour compression chiller

Cited by 27 publications

References 31 publications

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

Performance of Solar Absorption-Subcooled Compression Hybrid Cooling System for Different Flow Rates of Hot Water

CO 2 Subcooling

Contact Info

Product

Resources

About

CO ₂ Subcooling