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

Abstract

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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Modelling commercial refrigeration systems coupled with water storage to improve energy efficiency and perform heat recovery

“…Various software codes are available in the literature, able to simulate both the refrigeration and HVAC systems in supermarkets, which can be employed to perform such evaluations. Among all, we mention here Cybermart (Arias, 2005, Arias andLundqvist, 2005), EnergyPlus (Stovall and Van Baxter, 2010), and SuperSim Tassou, 2011a and2011b). Only Energy Plus is freely available, and can be used for the simulation of systems with some complexity but made of conventional components (Cortella et al, 2011).…”