Aiming to enable robust large-scale fault diagnostics and optimized control for supermarket refrigerationsystems, a data-driven grey box model for an evaporator and its surrounding cooling cabinet (or room) ispresente...Aiming to enable robust large-scale fault diagnostics and optimized control for supermarket refrigerationsystems, a data-driven grey box model for an evaporator and its surrounding cooling cabinet (or room) ispresented. It is a non-linear model with two states: the cabinet temperature and the refrigerant mass in theevaporator. To demonstrate its applicability, data with one-minute sampling resolution from ten evaporators ina supermarket in Otterup (Denmark) was used. The model parameters were estimated using a Kalman filter andthe maximum likelihood method. Since the dynamical properties of the cabinets constantly change as goodsare added and removed, the parameters were re-estimated for each night, over a period of approximately 2.5years. The model is validated through a statistical analysis of the residuals and the importance of the ongoingre-estimation of parameters is highlighted. Furthermore, the physical meaning of the estimated parameters isdiscussed and potential applications for characterization and classification of cabinets are demonstrated, byshowing how they can be differentiated as either open- or closed cabinets or rooms, using only the estimatedheat transfer coefficients and heat capacities. For a selected case it is shown that the estimated parametervalues are close to physics derived values, and that the accuracy measured by the standard errors of theestimates is approximately ±10% relative to the estimated values. The analysis demonstrates that the modelis robust, accurate and reliable in terms of estimating physically meaningful parameters and it is thereforeappropriate for large-scale implementation.展开更多
Since the nuclear disaster occurred from huge earthquake in Japan 2011, Japanese energy generation system has been expected to prioritize safety and trustworthiness. To meet this requirement, distributed power supply ...Since the nuclear disaster occurred from huge earthquake in Japan 2011, Japanese energy generation system has been expected to prioritize safety and trustworthiness. To meet this requirement, distributed power supply systems are considered to be one of solutions. In this study, we aimed to conserve energy and reduce carbon dioxide emission of supermarket which installed a novel environment-friendly dispersed power. We focused the energy used by refrigerated cabinets. We built small scale model of supermarket which was equipped with dispersed power. From this scale model, the energy conservation effect of supercooling is from 10% to 25% during the summertime and intermediate time. At last, we found that when outside temperature is about 14 ℃ or more, supercooling was effective. In addition, since energy consumption of refrigerated cabinet is influenced by inside enthalpy, we controlled the inside air temperature and humidity by installing desiccant system and examined its effect.展开更多
基金This document is the results of the research projects Digital twins for large-scale heat pumps and refrigeration systems(EUDP 64019-0570)Flexible Energy Denmark(FED)(IFD 8090-00069B).
文摘Aiming to enable robust large-scale fault diagnostics and optimized control for supermarket refrigerationsystems, a data-driven grey box model for an evaporator and its surrounding cooling cabinet (or room) ispresented. It is a non-linear model with two states: the cabinet temperature and the refrigerant mass in theevaporator. To demonstrate its applicability, data with one-minute sampling resolution from ten evaporators ina supermarket in Otterup (Denmark) was used. The model parameters were estimated using a Kalman filter andthe maximum likelihood method. Since the dynamical properties of the cabinets constantly change as goodsare added and removed, the parameters were re-estimated for each night, over a period of approximately 2.5years. The model is validated through a statistical analysis of the residuals and the importance of the ongoingre-estimation of parameters is highlighted. Furthermore, the physical meaning of the estimated parameters isdiscussed and potential applications for characterization and classification of cabinets are demonstrated, byshowing how they can be differentiated as either open- or closed cabinets or rooms, using only the estimatedheat transfer coefficients and heat capacities. For a selected case it is shown that the estimated parametervalues are close to physics derived values, and that the accuracy measured by the standard errors of theestimates is approximately ±10% relative to the estimated values. The analysis demonstrates that the modelis robust, accurate and reliable in terms of estimating physically meaningful parameters and it is thereforeappropriate for large-scale implementation.
文摘Since the nuclear disaster occurred from huge earthquake in Japan 2011, Japanese energy generation system has been expected to prioritize safety and trustworthiness. To meet this requirement, distributed power supply systems are considered to be one of solutions. In this study, we aimed to conserve energy and reduce carbon dioxide emission of supermarket which installed a novel environment-friendly dispersed power. We focused the energy used by refrigerated cabinets. We built small scale model of supermarket which was equipped with dispersed power. From this scale model, the energy conservation effect of supercooling is from 10% to 25% during the summertime and intermediate time. At last, we found that when outside temperature is about 14 ℃ or more, supercooling was effective. In addition, since energy consumption of refrigerated cabinet is influenced by inside enthalpy, we controlled the inside air temperature and humidity by installing desiccant system and examined its effect.
