Hassan Harb - Academia.edu (original) (raw)
Uploads
Papers by Hassan Harb
ABSTRACT A shift to a decentralized power generation mainly based on Renewable Energy Sources (RE... more ABSTRACT A shift to a decentralized power generation mainly based on Renewable Energy Sources (RESs) is essential to meet the climate protection goals of reducing greenhouse gas emissions. The fluctuating generation of RESs poses challenges for the stability of the electrical grid. Therefore, energy management systems (EMSs) are essential to cope with the volatility of RESs through an intelligent coordination of Distributed Energy Resources (DERs). Thus, EMSs ensure the security of energy supply and enhance the integration of RES. In this work, an energy management strategy based on a multi-agent system (MAS) for a microgrid is presented. The control strategy exploits the flexible operation of the DERs deployed in heating systems, which arises from using thermal storages, to adapt to the RESs fluctuations. This is performed by determining optimized schedules for the DERs using Mixed Integer Linear Programing (MILP) as well as thermal and electrical demand forecasting models. The coordination of the DER within the microgrid is achieved through a centralized and a decentralized approach for determining the operation schedules. Both approaches are assessed against a scenario in which the conventional heat driven operation of DERs is employed. The evaluation criteria comprise Primary Energy Consumption (PEC), reduction of CO 2 emissions, operation costs and integration of RES. Both centralized and decentralized approaches achieve significant reduction in PEC and CO 2 emissions compared to the heat driven scenario. The centralized approach achieves the highest coordination level by minimizing the import of external electricity and the highest integration of RESs. The decentralized approach is characterized by a high electricity export and achieves the lowest PEC and lowest net CO 2 balance.
The potential for utilization of the building mass thermal capacity for demand side management in... more The potential for utilization of the building mass thermal capacity for demand side management in the residential sector is addressed. A three apartment residential houses made of massive brick, equipped with a heat pump is modeled and its thermal behavior is simulated. It is shown that thermal storage capacity of the building can indeed contribute considerably to residential demand side management activities. Even after heating periods as short as two hours the heating demand for the following four hours can be reduced by almost 20 %. The slow temperature increase within the thermal mass and the heat conduction into deeper wall layers are thereby the main limiting factors.
In order to evaluate heat pump systems adequately, in this paper the framework of the so-called H... more In order to evaluate heat pump systems adequately, in this paper the framework of the so-called Hardware-in-the-Loop concept is applied to create dynamic and realistic boundary conditions. In particular, this means real components of a heat pump system are installed on a test facility, while the boundary conditions are emulated based on a real-time simulation of a complex building model. A future challenge in terms of evaluating heat pump systems in a fair manner are upcoming intelligent and complex control algorithms like predictive control. Hereby, a pure energetic assessment is insufficient, since these energy management systems often aims to reduce cost or to increase thermal comfort. Therefore, we suggest to involve among others also economical aspects as well as aspects of comfort in the characterization procedure of heat pumps. On the one hand, one advantage of the Hardware-in-the-Loop concept is, e.g. to be able to investigate indoor air temperatures and include this knowled...
Building and Environment, 2015
ABSTRACT The increasing installation of volatile renewable energy sources like photovoltaics and ... more ABSTRACT The increasing installation of volatile renewable energy sources like photovoltaics and wind enforces the need for flexibility options to match the renewable generation with the demand. One of these options is Demand Side Management (DSM) in the context of building energy systems combined with thermal storage systems. This paper discusses such concepts for DSM. A method for analyzing the flexibility that is needed to maintain the stability of the electrical grid is presented followed by the restrictions that are caused by meeting the heat demand and satisfying the comfort criteria of the residents. Approaches for simultaneously fulfilling these constraints as well as matching the flexibility needs of the electrical grid and the flexibility provided by the local building energy systems are discussed. To enhance the analysis options for the shown systems, a simulation platform that covers the electrical grid simulation, the building systems’ simulation and the control strategies is presented. This platform can be used to analyze different scenarios of building energy systems with different penetrations of renewable energy sources and different building types.
Renewable and Sustainable Energy Reviews, 2019
ABSTRACT A shift to a decentralized power generation mainly based on Renewable Energy Sources (RE... more ABSTRACT A shift to a decentralized power generation mainly based on Renewable Energy Sources (RESs) is essential to meet the climate protection goals of reducing greenhouse gas emissions. The fluctuating generation of RESs poses challenges for the stability of the electrical grid. Therefore, energy management systems (EMSs) are essential to cope with the volatility of RESs through an intelligent coordination of Distributed Energy Resources (DERs). Thus, EMSs ensure the security of energy supply and enhance the integration of RES. In this work, an energy management strategy based on a multi-agent system (MAS) for a microgrid is presented. The control strategy exploits the flexible operation of the DERs deployed in heating systems, which arises from using thermal storages, to adapt to the RESs fluctuations. This is performed by determining optimized schedules for the DERs using Mixed Integer Linear Programing (MILP) as well as thermal and electrical demand forecasting models. The coordination of the DER within the microgrid is achieved through a centralized and a decentralized approach for determining the operation schedules. Both approaches are assessed against a scenario in which the conventional heat driven operation of DERs is employed. The evaluation criteria comprise Primary Energy Consumption (PEC), reduction of CO 2 emissions, operation costs and integration of RES. Both centralized and decentralized approaches achieve significant reduction in PEC and CO 2 emissions compared to the heat driven scenario. The centralized approach achieves the highest coordination level by minimizing the import of external electricity and the highest integration of RESs. The decentralized approach is characterized by a high electricity export and achieves the lowest PEC and lowest net CO 2 balance.
The potential for utilization of the building mass thermal capacity for demand side management in... more The potential for utilization of the building mass thermal capacity for demand side management in the residential sector is addressed. A three apartment residential houses made of massive brick, equipped with a heat pump is modeled and its thermal behavior is simulated. It is shown that thermal storage capacity of the building can indeed contribute considerably to residential demand side management activities. Even after heating periods as short as two hours the heating demand for the following four hours can be reduced by almost 20 %. The slow temperature increase within the thermal mass and the heat conduction into deeper wall layers are thereby the main limiting factors.
In order to evaluate heat pump systems adequately, in this paper the framework of the so-called H... more In order to evaluate heat pump systems adequately, in this paper the framework of the so-called Hardware-in-the-Loop concept is applied to create dynamic and realistic boundary conditions. In particular, this means real components of a heat pump system are installed on a test facility, while the boundary conditions are emulated based on a real-time simulation of a complex building model. A future challenge in terms of evaluating heat pump systems in a fair manner are upcoming intelligent and complex control algorithms like predictive control. Hereby, a pure energetic assessment is insufficient, since these energy management systems often aims to reduce cost or to increase thermal comfort. Therefore, we suggest to involve among others also economical aspects as well as aspects of comfort in the characterization procedure of heat pumps. On the one hand, one advantage of the Hardware-in-the-Loop concept is, e.g. to be able to investigate indoor air temperatures and include this knowled...
Building and Environment, 2015
ABSTRACT The increasing installation of volatile renewable energy sources like photovoltaics and ... more ABSTRACT The increasing installation of volatile renewable energy sources like photovoltaics and wind enforces the need for flexibility options to match the renewable generation with the demand. One of these options is Demand Side Management (DSM) in the context of building energy systems combined with thermal storage systems. This paper discusses such concepts for DSM. A method for analyzing the flexibility that is needed to maintain the stability of the electrical grid is presented followed by the restrictions that are caused by meeting the heat demand and satisfying the comfort criteria of the residents. Approaches for simultaneously fulfilling these constraints as well as matching the flexibility needs of the electrical grid and the flexibility provided by the local building energy systems are discussed. To enhance the analysis options for the shown systems, a simulation platform that covers the electrical grid simulation, the building systems’ simulation and the control strategies is presented. This platform can be used to analyze different scenarios of building energy systems with different penetrations of renewable energy sources and different building types.
Renewable and Sustainable Energy Reviews, 2019