1,720,976 research outputs found
Model predictive controls for residential buildings with heat pumps: Experimentally validated archetypes to simplify the large-scale application
No full textExploiting the energy flexibility resulting from thermal loads management in buildings is one of the most promising solutions to contribute to the energy transition targets. To offer energy flexibility to the grid, the building should meet the requirements: (i) it needs electrically powered generation (e.g., through Heat Pumps) and (ii) advanced control techniques (e.g., Model Predictive Controls) must be implemented. In recent years, the scientific community has produced many studies demonstrating the potential of Model Predictive Controls combined with Heat Pumps to exploit energy flexibility in buildings. However, a large-scale deployment of such control techniques is still far off, both because of the not yet widespread use of Heat Pumps and the computational challenges involved in implementing them. The aim of this study is to contribute to the deployment of advanced control techniques for Heat Pumps systems in buildings by simplifying their implementation. At this aim, validated archetypes of Model Predictive Controls for Heat Pumps in residential buildings are proposed. The availability of archetypes can greatly facilitate the practical application of Model Predictive Control. In fact, they are adaptable to the characteristics of different buildings and Heat Pump installations and their structure is designed to have an acceptable trade-off between calculation time and prediction reliability. The archetypes cover three different types of heating systems: low temperature radiators without (i) and with (ii) integrated heat storage devices and (iii) underfloor heating system. All archetypes are applied to a real Heat Pump and validated through experimental campaigns. During the experimental test all the archetypes proved to be effective in controlling the real system and the results showed good reliability of the prediction model in the control (for all archetypes a Root Mean Square Error lower than 0.44 degrees C was obtained) and an optimizer success rate in Model Predictive Controls greater than 91 %. The archetypes proposed are provided as open-source tools that can be reused for similar cases to facilitate Model Predictive Controls implementation in heat pump systems
Heat pumps to upgrade existing CHP-DHN systems towards new generation thermal networks
Full text linkDistrict heating networks with combined heat and power systems and renewable energies are one of the most promising solutions for efficient and sustainable energy supply. In many cases, however, especially for district heating networks prior to the 4th generation, significant renovations are required to meet decarbonization targets. In this paper a study is proposed to evaluate the integration of high temperature heat pumps in an existing combined heat and power - district heating plant to reduce fossil fuel consumption and increase the exploitation of renewable energy sources. The plant is currently operating in central Italy and connects more than 1250 users. The identified solution implies lowering the district heating networks operating temperature and supplying power peaks with a high temperature heat pump acting as a booster. Results showed significant improvements in system performance especially in the winter months, due to the greater impact of lowering the temperature level of the district heating network during these months. Overall, the updated scenario allows the overall demand and ground heat losses to be reduced annually by 5.3 % and 13.5 % respectively. This reduces natural gas consumption by 13.3 % and avoids the emission of about 836 tCO2. The analysis provides guidelines for the upgrade of 3rd generation district heating network that can be useful for planning improvements towards newest generation thermal networks
Day-ahead optimal scheduling of smart electric storage heaters: A real quantification of uncertainty factors
Full text linkOptimized controls are particularly promising for flexible and efficient management of space heating and cooling systems in buildings. However, when controls are based on predictive models, their effectiveness is affected by the reliability of the models used. In this paper we propose a quantification analysis of some of the main uncertainty factors that can be observed in an optimal control really implemented in a building. A day-ahead optimal scheduling was applied to the heating system (composed of smart electric heaters with thermal storage) of a single room in an office building located in Osimo (Italy). The control algorithm is formulated to determine the charging periods of the heaters with the objective of minimizing the withdrawal of energy from the grid. The control takes into account the electricity produced by a photovoltaic plant and must maintain the internal air temperature close to an imposed setpoint.
Firstly, the actual application of the control is shown during two selected days. Secondly, the analysis is extended to quantify the impact on the control performance of the prediction uncertainty of the input variables. The variable that has the greatest impact is the weather forecast and, specifically, the cloudiness index, which determines the solar gains. The different moment in time in which the weather forecast is predicted has proved to have a significant impact on the charging periods of the heaters (expected variation ranges from -50% to + 100%) and on the prediction of the indoor air temperature (variations observed up to 40%)
Design optimization of energy flexibility for residential buildings
No full textDue to its progressive aging, the need to plan a long-term renovation strategy for the European building stock is increasingly urgent. Furthermore, the growing penetration of discontinuous and non-programmable renewable energy sources asks for an adaptable demand to the supply variability. Thus, the realization of new buildings which are both efficient and energy flexible can be a way to increase reliability and security of the current energy grid. Purpose of this work is to characterize the effect of different buildings renovation strategies on their energy flexibility performance obtained through electric heating energy demand management. The energy flexibility is quantified by means of a single indicator: the Flexibility Performance Indicator. As the Energy Performance Certificate, it is calculated with a standardized procedure. In this work, starting from a low energy performance reference building, the energy flexibility performance obtainable with different energy efficiency interventions is assessed. Eventually the extent of the requested investment combined with the potential electricity costs saving derived from it is evaluated
Energy flexibility curves to characterize the residential space cooling sector: The role of cooling technology and emission system
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Valorization of olive mill wastewater for Arthrospira platensis production
Full text linkIntending to reduce the related environmental impact of olive oil wastewater while producing new by-products, this research paper proposes an innovative solution for the treatment of wastewater that combines microfiltration and ultrafiltration techniques with microalgae cultivation. Laboratory scale analysis and pilot scale operation have been performed to assess the techno-economic viability of the olive mill wastewater for Arthrospira platensis production. More precisely, growth rate, time of division, and characterization (lipids, carbohydrates, proteins, and so forth) of microalgae are evaluated. The results obtained from the techno-economic analysis show that the integration of the systems makes it possible to efficiently exploit the inorganic nutrients of the olive mill wastewater for the cultivation of Arthrospira platensis. In particular, the quality of the obtained biomass complies with the food grade regulations, whereas avoided costs for the olive mill wastewater disposal bring a reduction of 70% in the biomass production cost
Integrated design of heat pump systems: A multi-objective optimized design methodology considering the mutual influence of design and control
No full textDesign optimization of energy flexibility for residential buildings
No full textDue to its progressive aging, the need to plan a long-term renovation strategy for the European building stock is increasingly urgent. Furthermore, the growing penetration of discontinuous and non-programmable renewable energy sources asks for an adaptable demand to the supply variability. Thus, the realization of new buildings which are both efficient and energy flexible can be a way to increase reliability and security of the current energy grid. Purpose of this work is to characterize the effect of different buildings renovation strategies on their energy flexibility performance obtained through electric heating energy demand management. The energy flexibility is quantified by means of a single indicator: the Flexibility Performance Indicator. As the Energy Performance Certificate, it is calculated with a standardized procedure. In this work, starting from a low energy performance reference building, the energy flexibility performance obtainable with different energy efficiency interventions is assessed. Eventually the extent of the requested investment combined with the potential electricity costs saving derived from it is evaluated
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