Electric Water Heater Modeling, DR Approaches Analysis and Study of Consumer Comfort for Demand Response

With the smart energy management system household residential appliances is able to participate in the demand response events. To reduce peak load demand and complexities in the local infrastructure DR can play an important role now a days. This paper presents a study and analysis of several papers on residential EWH DR modeling and implementation. It shows an overview of analysis of the most used and recent DR models for EWH. It also shows the analysis of the used methods to model this and the used approach in several papers. Additionally, the discussed consumer comforts and obtainable benefits in several papers by participating in DR events is also shown here. The study and analysis in this paper will contribute to the future research and encourage the end users to participate in households DR events.The present work was done and funded in the scope of the following projects: H2020 DREAM-GO Project (Marie Sklodowska-Curie grant agreement No 641794); SIMOCE (ANI|P2020 17690); and UID/EEA/00760/2019 funded by FEDER Funds through COMPETE program and by National Funds through FCT.info:eu-repo/semantics/publishedVersio

Study of pump control in residential grid-tied solar domestic hot water photovoltaic-thermal (PV-T) systems

A study of pump control focusing on active residential grid-connected solar domestic hot water (SDHW) photovoltaic-thermal (PV-T) systems was conducted. The main goal was to determine how the two main pump controls for this segment compare, namely the differential temperature static two-level hysteretic control (DTSTLHC) and the differential temperature static saturated hysteretic-proportional control (DTSSHPC), given the dual outputs of PV-T technology: heat and electricity. In order to do so, a dynamic PV-T collector model was developed for use in transient simulations and incorporated into a SDHW PV-T system model. A substantial number of annual simulations for each of the various locations selected were conducted to encompass the best performances using each control, with emphasis on multiple combinations of controller setpoints and mass flow rates. The results show PV-T systems using DTSSHPC and optimised for maximum auxiliary energy savings consistently outperforming those using DTSTLHC and optimised using the same criterion, though the opposite was true when seeking to optimise the electrical efficiency, with those using DTSTLHC performing best. However, the advantages at best correspond to single-digit percentages of the annual thermal energy demand, and less than 0.1% of the annual electrical efficiency. Similarly low performance advantages were reached from the standpoint of primary energy efficiency and load provision cost-effectiveness by using DTSSHPC, though not consistently due to the inability to reconcile electrical, thermal and parasitic performance advantages over DTSTLHC. Moreover, the advantages presented by DTSSHPC are low enough to be offset by one additional maintenance operation, which systems using this control are likelier to require first due to its complexity and higher switching frequencies. Finally, a study on setpoint selection for differential temperature controllers, namely DTSSHPC and DTSTLHC, for use in PV-T systems was also conducted using steady-state methods, which revealed marginal differences between setpoint selection for hybrid and non-hybrid systems

Active control of split system domestic solar water heaters

Solar water heaters have the potential to make large savings in greenhouse gas emissions in Australia. Long financial payback periods are the main reason that uptake of solar water heating is not more significant. This thesis investigates the potential improvement in performance of split-system solar water heaters by the addition of an active control system. This work builds upon "low flow" collector circulation theory and addresses the poor control available from the storage tank thermostat. Modelling suggests that the thermal efficiency of the water heater can be improved by about 25°/o, primarily through reduction of tank standing losses, if the thermostat is replaced by a smart controller. Auxiliary energy consumption is reduced proportionally. If realisable, these savings recover the capital cost of the additional controller in several years. The consumer will benefit from further savings in auxiliary energy consumption over the life of the system and so the payback will be more attractive. The active control strategy is based upon predicting and controlling the energy content of the storage tank. The control strategy is energy tariff sensitive and may be set by the householder to behave in an energy efficient or a cost effective manner. A number of technologies and design improvements regarding forecasting of the energy supply and demand were also developed in this work. The auxiliary heater was moved outside of the tank and placed in series with the solar collector via a switching valve arrangement. The collector circulation pump was also used to circulate water through the auxiliary heater effectively providing a variable volume, variable temperature thermostat. A new variable power pump controller was developed for the existing circulation pump to allow fine temperature control of water returning from both the auxiliary and solar heat sources so that disruption to thermal stratification in the tank was minimised. The predictive performance of the collector could then be decoupled from the state of the tank. This thesis explores a practical implementation of the active control strategy and provides an insight into the actual performance and areas of sensitivity of the technology. The proposed design changes require more thorough validation including field trials to evaluate the load learning algorithms. Performance of the active controller would be improved if the heating circuit intake position could be actuated vertically within the tank or if hot and cold water could be fully separated in the tank

Sustainable energy for a resilient future: proceedings of the 14th International Conference on Sustainable Energy Technologies

Volume I, 898 pages, ISBN 9780853583134 Energy Technologies & Renewables Session 1: Biofuels & Biomass Session 5: Building Energy Systems Session 9: Low-carbon/ Low-energy Technologies Session 13: Biomass Systems Session 16: Solar Energy Session 17: Biomass & Biofuels Session 20: Solar Energy Session 21: Solar Energy Session 22: Solar Energy Session 25: Building Energy Technologies Session 26: Solar Energy Session 29: Low-carbon/ Low-energy Technologies Session 32: Heat Pumps Session 33: Low-carbon/ Low-energy Technologies Session 36: Low-carbon/ Low-energy Technologies Poster Session A Poster Session B Poster Session C Poster Session E Volume II, 644 pages, ISBN 9780853583141 Energy Storage & Conversion Session 2: Heating and Cooling Systems Session 6: Heating and Cooling Systems Session 10: Ventilation and Air Conditioning Session 14: Smart and Responsive Buildings Session 18: Phase Change Materials Session 23: Smart and Responsive Buildings Session 30: Heating and Cooling System Session 34: Carbon Sequestration Poster Session A Poster Session C Poster Session D Policies & Management Session 4: Environmental Issues and the Public Session 8: Energy and Environment Security Session 12: Energy and Environment Policies Poster Session A Poster Session D Volume III, 642 pages, ISBN 9780853583158 Sustainable Cities & Environment Session 3: Sustainable and Resilient Cities Session 7: Energy Demand and Use Optimization Session 11: Energy Efficiency in Buildings Session 15: Green and Sustainable Buildings Session 19: Green Buildings and Materials Session 24: Energy Efficiency in Buildings Session 27: Energy Efficiency in Buildings Session 28: Energy Efficiency in Buildings Session 31: Energy Efficiency in Buildings Session 35: Energy Efficiency in Buildings Poster Session A Poster Session D Poster Session