Measuring Instruments in Chiller Plants and Uncertainties in Performance Evaluation

Yik, Francis W.H.; Chiu, Tsung-Chih

doi:10.1080/1023697x.1998.10667770

Cited by 7 publications

(3 citation statements)

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“…Implementation of the optimization control for chiller plants requires that the plants are equipped with adequate instrumentation for measuring operating parameters of equipment and that the measured records are analyzed regularly. 15 Reliable ®eld data from proper instrumentation to chiller plants are essential to evaluate the actual performance. Then, by comparing the performance lines of actual data and simulated data, it is possible to remove problems of improper operation or unsatisfactory control of the system.…”

Section: Consideration Of Operating Ef®ciency In Relation To the Load And Outdoor Temperaturementioning

confidence: 99%

Part load efficiency of air-cooled multiple-chiller plants

Chan¹,

2002

Building Services Engineering Research and Technology

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This paper reports an analysis of the energy efficiency of air-cooled chiller plants in buildings and opportunity of improved part load efficiency. Load-frequency profile, weather-load profile and thermal performance lines obtained by simulation of typical office and hotel buildings in a subtropical climate are examined to address the methods of determining the plant size, identifying the loading characteristics, optimizing the combination of multiple-chillers and evaluating the energy saving alternatives in design or retrofit. It is shown that the percentage design load for office is best related to external temperature; for hotels the product of external temperature and humidity is more appropriate as a climatic index. The results indicate that for a particular value of percentage design load, the likely outdoor temperature can be determined statistically, and the consumption can be determined from a set of chiller efficiency curves as a function of chiller part load ratio and entering condenser air temperature. The opportunity for improving the operating efficiency of air-cooled multiple-chiller plants by lowering the condensing temperature at lower outdoor temperatures is discussed.

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Section: Consideration Of Operating Ef®ciency In Relation To the Load And Outdoor Temperaturementioning

confidence: 99%

Part load efficiency of air-cooled multiple-chiller plants

Chan¹,

2002

Building Services Engineering Research and Technology

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“…Unfortunately, few buildings in Hong Kong are equipped with sufficient energy meters that will allow air-conditioning electricity consumption to be determined to an acceptable level of accuracy. 7,8 In view of this, computer simulation was also adopted for assessing existing buildings under HK-BEAM.…”

Section: Simplified Model For Predicting Air-conditioning Electricity Usementioning

confidence: 99%

“…As both combinations offer similar 'goodness of fit' in terms of the coefficient of determination (r 2 ), it was uncertain which combination would give the best correlation. A further analysis on the multicollinearity (near linear dependence) between all the independent variables selected in the three procedures were checked by examining the vari-ance inflation factor (VIF) of the selected independent variables, 14 where: (8) In Equation ( 8), r i 2 denotes the coefficient of multiple determination for the ith independent variable when regressed on the remaining independent variables. A high VIF value points to collinearity, and inclusion of variables that have a significant collinearity with other variables in a multiple linear regression model would affect the prediction accuracy of the model, and should be avoided.…”

Section: Multiple Regression Analysismentioning

confidence: 99%

Simplifying energy performance assessment in the Hong Kong Building Environmental Assessment Method

Lee¹,

Yik²,

Burnett

2001

Building Services Engineering Research and Technology

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In the Hong Kong Building Environmental Assessment Method (HK-BEAM) for air-conditioned office premises, energy use for air-conditioning constitutes one major item of assessment. The current assessment method for existing offices is based on computer simulation predictions. Following a recent review of the HK-BEAM scheme, simplified models have been developed for use in the assessment as an alternative to the detailed simulation method. These models are multiple linear regression models relating the annual electricity use for air-conditioning, and the maximum electricity demand, in an office building to the key characteristics of the building envelope and the air-conditioning system. Use of these models can reduce the effort required for data collection and input, and will allow the assessors to more quickly complete an assessment. In addition, additional parametric studies can be performed within much less time, which will help assessors in formulating advice to developers/designers on measures that will lead to improved energy performance and thus higher credits. This paper summarizes the review findings and describes the approach taken in the establishment of the regression models. Comparison of predictions by the detailed computer simulation method and the alternative method showed that the latter could provide estimates close enough to the simulation predictions for the purpose of assessing the credits to be awarded to a building for its energy performance.

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