Optimum Setpoint of Condensing Temperature for Air-Cooled Chillers

Chan, K.T.; Yu, F.W.

doi:10.1080/10789669.2004.10391095

Cited by 42 publications

(46 citation statements)

References 9 publications

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“…This is the main reason for the rapid increase of power usage during peak hours in summer that leads to higher energy cost [10]. An efficient power demand management and effective power usage control for air-conditioning system will greatly reduce power consumption and the associated energy cost [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Analysis of energy and carbon dioxide emission caused by power consumption

Sung

Tsai

Wang

et al. 2010

Int. J. Energy Res.

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SUMMARYThe main objective of this on-site study is to use a full-scale Heating, Ventilating, and Air-Conditioning (HVAC) system installed in an office building in Taiwan for comparing the power consumption, energy-saving, and carbon dioxide (CO 2 ) reduction of two different strategies for controlling the HVAC. These strategies are the Constant Volume (CV) system [Constant Air Volume1Constant-flow], and the Variable Volume (VV) system [Variable Air Volume 1Variable-flow]. The on-site experimental results indicate that average power consumptions are 164 kW for the CV system, and 88 kW for the VV system; the average electric current drops from 469 A for the CV system to 258 A for the VV system. Approximately 46% of the average energy-saving can be achieved if the HVAC system is operated as a VV system. Additionally, the reduced quantity of accumulated CO 2 emission varies from 67 to 3687 kg with 0.637 kg CO 2 kwh À1 emission factor during the office hours of 08:30 (a.m.)-17:00 (p.m.). The results demonstrate that switching the operation of an office building HVAC system from CV to VV will significantly enhance energy-savings and CO 2 reduction. This studywill offer useful information for evaluating an indoor environmental policy with respect to energy-savings and CO 2 emission reduction for office HVACs used in subtropical regions.

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Section: Introductionmentioning

confidence: 99%

Analysis of energy and carbon dioxide emission caused by power consumption

Sung

Tsai

Wang

et al. 2010

Int. J. Energy Res.

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“…Furthermore, fan power can be saved by turning off unnecessary constant-speed fans in steps under the existing condenser design. Yet the step-by-step variation in heat-rejection airflow is inappropriate to control the condensing temperature at its set point [6,7]. It is desirable to continuously modulate the heat-rejection airflow via variable-speed fans in order to investigate the trade-off between compressor power and condenser fan power.…”

Section: Introductionmentioning

confidence: 99%

“…In this situation, the condensing temperature will be controlled at above 30°C at an evaporating temperature of 5°C. The use of electronic expansion-valves, on the other hand, enables the condensing temperature to drop to as low as 10°C if there is no problem of compressor lubrication [6,7].…”

Section: Introductionmentioning

confidence: 99%

Improved condenser design and condenser-fan operation for air-cooled chillers

Chan

2006

Applied Energy

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“…To predict the total fan power consumption of the air cooled condensers and actual head pressure in the system at part-load conditions, a simplified condenser model combined with fan power calculation has been utilised (Chan and Yu, 2004). When the geometric characteristics and fan particulars of a particular condenser are known and computational time is not an important consideration in the simulations, a detailed condenser model can also be employed to evaluate the effect of heat exchanger design parameters on system performance (Ge and Cropper, 2004).…”

Section: Condenser Modelmentioning

confidence: 99%

“…When refrigerant properties (temperature and pressure) at condenser inlet and outlet, refrigerant mass flow rate and ambient air temperature are available at steady state, the simplified model is able to predict the required air flow rate, number of fans operating and total fan power consumption using the following equations (Chan and Yu, 2004):…”

Section: Condenser Modelmentioning

confidence: 99%

Performance evaluation and optimal design of supermarket refrigeration systems with supermarket model “SuperSim”, Part I: Model description and validation

Tassou

2011

International Journal of Refrigeration

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Conventional supermarket refrigeration systems are responsible for considerable CO 2 emissions due to high energy consumption and large quantities of refrigerant leakage.In the effort to conserve energy and reduce environmental impacts, an efficient design tool for the analysis, evaluation and comparison of the performance of alternative system designs and controls is required. This paper provides a description of the modelling procedure employed in the supermarket simulation model 'SuperSim' for the simulation of the performance of centralised vapour compression refrigeration systems and their interaction with the building envelope and HVAC systems. The model which has been validated against data from a supermarket has been used for the comparison of R404A and CO 2 refrigeration systems and the optimisation of the performance of transcritical CO 2 systems. These results are presented in Part II of the paper. IntroductionA modern supermarket requires considerable amounts of electricity and gas for refrigeration, lighting, baking and the maintenance of a comfortable retail environment for the staff and customers. The total electrical energy consumption of grocery stores is approximately 12 TWh and represents approximately 3.5% of the UK's total electrical energy consumption (Tassou, 2007) More than half of the energy used in a modern supermarket can be attributed to refrigeration systems.Lighting accounts for between 20% and 25% and HVAC and ancillary services for the remainder (Tassou and Ge , 2008). The refrigeration system is also charged with a large amount of refrigerant, in the majority of cases HFC, which is directly responsible for significant CO 2 emissions due to refrigerant leakage from the system.To increase the energy efficiency of supermarket refrigeration systems, several advanced technologies can be applied, which include more efficient components such as compressors and heat exchangers, combined heat and power and trigeneration in combination with sorption refrigeration systems, heat recovery, natural refrigerants and advanced control strategies and system integration (Tassou and Ge , 2008). For the evaluation and ultimate implementation of such technologies, simulation with an efficient and reliable system model could be the optimum way to compare an experiment which may be overly expensive and time consuming to be achievable otherwise.There are currently four supermarket energy simulation software with built-in supermarket refrigeration system models in the open literature which are:"Cybermart" (Arias, 2004) , "EnergyPlus" (EnergyPlus, 2009), "Retscreen" (RETScreen, 2009), and "SuperSim" . In addition, there are two other software for 5 supermarket refrigeration systems (van der Sluis, 2004), "Econu Koeling" (Econu Koeling, 2003) and "ORNL Supermarket Spreadsheets" (ORNL, 2003). These, however, do not incorporate the simulation of the building and HVAC systems and will not be considered further in this paper.The four supermarket energy simulation models universally recognize that ...

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Optimum Setpoint of Condensing Temperature for Air-Cooled Chillers

Cited by 42 publications

References 9 publications

Analysis of energy and carbon dioxide emission caused by power consumption

Analysis of energy and carbon dioxide emission caused by power consumption

Improved condenser design and condenser-fan operation for air-cooled chillers

Performance evaluation and optimal design of supermarket refrigeration systems with supermarket model “SuperSim”, Part I: Model description and validation

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