The Physical Optimum as an Ideal Reference Value for Balancing Thermodynamic Processes Integrating the Exergetic Evaluation by the Example of Heat Supply

Volta, Dirk; Weber, Samanta A.

doi:10.3390/en14154426

Cited by 3 publications

(7 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar to the exergy analysis, the 'Physical Optimum' method introduced by Volta and Weber [29] serves to evaluate processes against a thermodynamically ideal reference process. The 'physical optimum factor' represents the ratio of 'the real amount of energetic expense [.…”

Section: Previous Literature and Indicatorsmentioning

confidence: 99%

Catalyzing Cooling Tower Efficiency: A Novel Energy Performance Indicator and Functional Unit including Climate and Cooling Demand Normalization

Wenzel,

Fensterle,

Radgen

2023

Sustainability

View full text Add to dashboard Cite

Energy and climate targets necessitate efficiency indicators to reflect resource-saving potentials. Prevailing indicators for cooling towers, however, often omit the effect of outside conditions. Hence, this study introduces an innovative indicator grounded in the energy efficiency ratio. Our proposed metric is the cost–benefit ratio between electricity demand and the thermodynamic minimum airflow. Thus, we call the novel indicator the airflow performance indicator. To validate its feasibility, we apply the indicator first to an extensive dataset encompassing 6575 cooling tower models and second to a year-long case study involving a data center’s wet cooling system. As a result, the energy performance indicator demonstrates that dry cooling requires eight times more minimum airflow at the median than evaporative cooling would, directly correlating to the fan power. Furthermore, efficiency benchmarks derived from the dataset of 6575 cooling tower models provide a comparative assessment of the case study. Defining the quantified benefit as minimum airflow additionally underscores the limitations of free cooling as the wet cooling system only partly covers the cooling demand, requiring chillers additionally. In conclusion, the indicator empowers the identification of energy-saving potentials in the selection, design, and operation of cooling towers. Moreover, the functional unit definition provides a foundation for future life cycle assessments of cooling towers, enhancing cooling tower efficiency and sustainability.

show abstract

Section: Previous Literature and Indicatorsmentioning

confidence: 99%

Catalyzing Cooling Tower Efficiency: A Novel Energy Performance Indicator and Functional Unit including Climate and Cooling Demand Normalization

Wenzel,

Fensterle,

Radgen

2023

Sustainability

View full text Add to dashboard Cite

show abstract

“…The physical optimum (PhO) method refers to the theoretical ideal reference process, which requires a minimum amount of energy (and other resources) [58]. The ratio of real resource input to this ideal reference value is called the PhO factor, which is the indicator.…”

Section: Smeets and Weteringsmentioning

confidence: 99%

“…Dynamic analyses can be performed by extending MFA, SFA, and LCA (including LCI) towards dynamic MFA [72,73], dynamic SFA [74], and dynamic LCA [75], respectively. The framework of the PhO method is explicitly intended for dynamic analysis [58] (p. 13). Other methods can also be extended, although the additional understanding might be minor in some cases compared to the increased complexity.…”

Section: Temporal and Spatial Resolutionmentioning

confidence: 99%

“…For example, some approaches use MFA [4] or an energy analysis [77]. Volta and Weber [58] describe using the PhO for cooling towers with regard to evaporated water. Theoretically, when using the PhO, no draw-off, blow-down, or sludge removal would be necessary, meaning that the water demand would equal the amount of evaporated water.…”

Section: Existing Studies On Cooling Systemsmentioning

confidence: 99%

See 1 more Smart Citation

Multi-Criteria Comparison of Energy and Environmental Assessment Approaches for the Example of Cooling Towers

Wenzel

Radgen

2022

ASI

View full text Add to dashboard Cite

Cooling towers remove economically or technically unusable heat using considerable amounts of electricity and, in many cases, water. Several approaches, which vary in methodology, scope, and level of detail, are used for environmental evaluations of these cooling systems. Although the chosen approach has a significant impact on decisions made at the plant level, no methodology has yet been standardized for selecting the approach that best serves the objectives of the evaluation. Thus, this paper provides comparison criteria for the systematic selection of suitable evaluation methods for cooling towers and classifies how the methods score in this respect. These criteria, such as ‘life cycle thinking’, ‘inventoried physical quantities’, ‘temporal resolution’, ‘formalization’, and ‘data availability’, are grouped by overall evaluation objectives such as ‘thoroughness’, ‘scientific soundness’, and ‘usability’. Subsequently, these criteria were used to compare material flow analysis, energy analysis, environmental network analysis, life cycle inventory, life cycle assessment, environmental footprint methods, emergy analysis, exergy analysis, and the physical optimum method. In conclusion, material flow analysis is best suited for the analysis of cooling towers when impact assessment is not required; otherwise, life cycle assessment meets most of the defined criteria. Moreover, only exergy-based methods allow for the inclusion of volatile ambient conditions.

show abstract

“…Kerpen [5] analyzes differences between the PhO and the exergy evaluation pointing out the advantages of each method. Volta and Weber [6] additionally explain the integration of the state variable exergy into the evaluation with the PhO.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Energetic Efficiency of Gas Separation Technologies Using the Physical Optimum by the Example of Oxygen Supply Options

2022

Self Cite

View full text Add to dashboard Cite

This study applies the Physical Optimum (PhO) as a reference value to rate the efficiency of two technical options for the oxygen supply of a hospital. The systematic comparison of the alternative processes using the PhO as a benchmark for the minimum input (exergy in this case) required to run a process with a certain benefit allows to determine the potential for optimization of each technology. Differences are analyzed by visualizing the losses of each individual production step in a process as well as by the resulting overall energy demand, including the primary energy. Possible alternatives are purchasing liquid oxygen from a cryogenic process or the production by means of Pressure Swing Adsorption (PSA) on site. The cryogenic production shows a lower exergy demand even though it also has a higher potential for optimization. Yet, the total losses, significantly impacted by the unavoidable transportation, sum up, resulting in the conclusion that the PSA is the preferable option overall, considering energy aspects. Finally, additional criteria such as economic, legal, and structural consequences of the respective choices are briefly outlined.

show abstract

The Physical Optimum as an Ideal Reference Value for Balancing Thermodynamic Processes Integrating the Exergetic Evaluation by the Example of Heat Supply

Cited by 3 publications

References 5 publications

Catalyzing Cooling Tower Efficiency: A Novel Energy Performance Indicator and Functional Unit including Climate and Cooling Demand Normalization

Catalyzing Cooling Tower Efficiency: A Novel Energy Performance Indicator and Functional Unit including Climate and Cooling Demand Normalization

Multi-Criteria Comparison of Energy and Environmental Assessment Approaches for the Example of Cooling Towers

Comparison of the Energetic Efficiency of Gas Separation Technologies Using the Physical Optimum by the Example of Oxygen Supply Options

Contact Info

Product

Resources

About