23 research outputs found
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Cooling load forecasting-based predictive optimisation for chiller plants
Extensive electric power is required to maintain indoor thermal comfort using heating, ventilation and air conditioning (HVAC) systems, of which, water-cooled chiller plants consume more than 50% of the total electric power. To improve energy efficiency, supervisory optimisation control can be adopted. The controlled variables are usually optimised according to instant building cooling load and ambient wet bulb air temperature at regular time intervals. In this way, the energy efficiency of chiller plants has been improved. However, with an inherent assumption that the instant building cooling load and ambient wet bulb temperature remain constant in the coming time interval, the energy efficiency potential has not been fully realised, especially when cooling loads vary suddenly and extremely. To solve this problem, a cooling load forecasting-based predictive optimisation method is proposed. Instead of minimising the instant system power according to the instant building cooling load and ambient wet bulb temperature, the controlled variables are derived to minimise the sum of the instant system power and one-time-step-ahead future system power according to both instant and forecasted future building cooling loads. With this method, the energy efficiency potential of a chiller plant can be further improved without shortening the operation time interval. 80% redundant energy consumption has been reduced for the sample chiller plant; energy can be saved for chiller plants that work for years. The evaluation on the effect of cooling load forecasting accuracy turns out that the more accurate the forecasts are, the more redundant energy consumption can be reduced
An integrated model for the design of air-cooled chiller plants for commercial buildings
Cooling load calculation is the first step in designing the air-conditioning system of a building. The calculated
cooling capacity with appropriate buffer is then used to select the number and size of chillers in the
system. Nþ 1 is a common formula used by designers to size the chiller plants in Hong Kong buildings,
where N is the actual number of chillers required and 1 is a redundant chiller provided to ensure reliability.
This paper reviews the problem of excess capacity and discusses the risk exposure of chiller systems
without redundant chillers. The cooling load profiles of the chiller plants of four medium-sized commercial
buildings inHong Kongare reviewed. The risk exposure of chiller systemswithout redundant chillers can be
minimized byapplying risk-based preventive maintenance. The just-in-demand design reduces capital cost
of the building and frees up funds for continuous energy measurement and improving the energy efficiency
of chiller plant systems. This paper presents a model for designing chiller plants that improves the energy
efficiency of the plant in a cost effective and thoughtful manner. It is designed with consideration of the life
cycle of the plant and real-time continuous commissioning, monitoring, measurement, comparison and
execution for better energy manageme
Recommended from our members
Cooling load forecasting-based predictive optimisation for chiller plants
Extensive electric power is required to maintain indoor thermal comfort using heating, ventilation and air conditioning (HVAC) systems, of which, water-cooled chiller plants consume more than 50% of the total electric power. To improve energy efficiency, supervisory optimisation control can be adopted. The controlled variables are usually optimised according to instant building cooling load and ambient wet bulb air temperature at regular time intervals. In this way, the energy efficiency of chiller plants has been improved. However, with an inherent assumption that the instant building cooling load and ambient wet bulb temperature remain constant in the coming time interval, the energy efficiency potential has not been fully realised, especially when cooling loads vary suddenly and extremely. To solve this problem, a cooling load forecasting-based predictive optimisation method is proposed. Instead of minimising the instant system power according to the instant building cooling load and ambient wet bulb temperature, the controlled variables are derived to minimise the sum of the instant system power and one-time-step-ahead future system power according to both instant and forecasted future building cooling loads. With this method, the energy efficiency potential of a chiller plant can be further improved without shortening the operation time interval. 80% redundant energy consumption has been reduced for the sample chiller plant; energy can be saved for chiller plants that work for years. The evaluation on the effect of cooling load forecasting accuracy turns out that the more accurate the forecasts are, the more redundant energy consumption can be reduced
A glycine to aspartic acid substitution of COL2A1 in a family with the Strudwick variant of spondyloepimetaphyseal dysplasia
Combined proteomics and transcriptomics approaches reveal the mechanism of neurodegeneration in Parkinson's Disease PC12 model
Poster presentation - Proteomics: Feneral: MP 077This journal supplement is the 60th ASMS Conference ProgramThe 60th ASMS Conference on Mass Spectrometry and Allied Topics, Vancouver, Canada, 20-24 May 2012. In Journal of The American Society for Mass Spectrometry, 2012, v. 23 suppl. 1, p. S56, abstract no. MP 07
A novel boron–nitrogen intumescent flame retardant coating on cotton with improved washing durability
202209 bckwAccepted ManuscriptRGCPublishe