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Dynamic Tariff-Subsidy Method for PV and V2G Congestion Management in Distribution Networks
摘要： This paper proposes a dynamic tariff-subsidy (DTS) method for congestion management in distribution networks with high penetration of photovoltaics (PV), heat pumps (HPs) and electric vehicles (EVs) with vehicle-to-grid (V2G) function. The DTS method is an extension of the dynamic tariff method proposed in the previous study. With the DTS, the regulation prices can be positive (tariff) or negative (subsidy). The study shows that the negative regulation price is necessary and very effective to solve congestion due to feed-in power flows, such as PVs and EVs in the V2G mode. In the study, dual decomposition of a convex quadratic model is proposed in addition to a conventional method for the DTS calculation. The case studies on the Roy Billinton Test System (RBTS) demonstrate the efficacy of the DTS method for congestion management in distribution networks.
关键词： distribution system operator (DSO),electric vehicle (EV),photovoltaics (PV),dynamic tariff-subsidy,Congestion management,heat pump (HP)
更新于2025-09-23 15:22:29
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Experimental Study on the Cogeneration Performance of Roll-bond-PVT Heat Pump System with Single Stage Compression During Summer
摘要： Photovoltaic thermal (PVT) heat pump technology refers to the integration of photovoltaic and solar heat pump, representing the deep exploitation and utilization of solar energy. In this paper, roll-bond-PVT heat pump (RB-PVTHP) system with single stage compression is proposed and investigated experimentally. The roll-bond-PVT (RB-PVT) unit is introduced in detail which is combined with the photovoltaic module and single-sided roll-bond evaporation heat exchanger laminating together. The designed experimental system consists of 4 pieces of RB-PVT units, 1HP heat pump unit and 150L heat storage tank, which is also equipped with various monitoring sensors to explore the system operating characteristics. Then the performance evaluation method of the unit and system is proposed. The experimental investigation on the cogeneration performance of the system in northern China during summer is carried out simultaneously, in terms of the thermal efficiency, electrical efficiency, thermal-based overall efficiency of the unit and heating COP of the system. The operating characteristics monitoring results show that the system works in a long-term stable condition during the daytime with considerable cogeneration performance. The detailed performance parameters have been given in this paper. This study demonstrates that the RB-PVTHP system has the large-scale practically feasible application value in northern China.
关键词： Single-sided roll-bond evaporator,PVT,Cogeneration performance evaluation,Roll-bond-PVT heat pump
更新于2025-09-23 15:21:21
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Performance analysis of a heat pump-based photovoltaic/thermal (PV/T) system
摘要： Photovoltaic/thermal (PV/T) system produces both heat and electricity simultaneously with the advantages of better space utilization and higher conversion efficiency over individual solar thermal and solar photovoltaic (PV) system when operated separately. The PV/T system can control the operating temperature of PV by passing a heat transfer fluid through a heat exchanger attached to the rear of the modules. The present study analyses the performance of one such in-house built system, where the heat transfer fluid is refrigerant. Refrigerant-based PV/T system involves the integration of evaporator coils of the heat pump and PV module to form a cogeneration type system known as photovoltaic/thermal–solar assisted heat pump (PV/T–SAHP). The prototype of the PV/T–SAHP was fabricated with a double glass PV module instead of a conventional module with polyvinyl fluoride backsheet. Initially, the performance characteristics of the system are analyzed in detail using the experimental observations under a typical clear sky condition during the transition season. Following, the year-round performance of the system is predicted using an already validated numerical model. It was found that the present system can improve the average electrical efficiency by 15.20% and can achieve a coefficient of performance of 2.96.
关键词： Refrigerant-based PV/T system,Thermal management of PV module,Double glass PV module,Heat pump
更新于2025-09-23 15:21:01
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A field study on the application of distributed temperature sensing technology in thermal response tests for borehole heat exchangers
摘要： Although the enhanced thermal response test (ETRT) method has been used to determine the distribution of ground temperatures and effective thermal conductivities, there are a number of obstacles which limit the wide application of this technology in the discipline of geoengineering. In this literature, four aspects of ETRT technology were investigated: (a) acquisition of ground temperature, (b) installation of the heat exchange tubes, (c) optimization of the monitoring positions, and (d) the difference in thermal conductivity obtained by the ETRT and numerical simulation. To investigate these issues, a field trial was carried out in Heze, Shandong Province, China, and the corresponding numerical models were built. The results demonstrate that: (i) the conventional methods that infer undisturbed ground temperature using water in tubes have large errors, whereas the distributed temperature sensing (DTS) technique enables the measurement of precise temperature profiles; (ii) the thermal conductivity measured using double U-tubes reflects the soil thermal property more accurately than that for a single U-tube; (iii) it is more reasonable to install optical fibers outside the U-tube sidewall than inside the observation tube; and (iv) it is essential to quantitatively consider various interface thermal impedance when estimating ground thermal conductivities using numerical simulation.
关键词： Fiber optic sensor,Distributed temperature sensing (DTS),Ground-coupled heat pump (GCHP),Thermal conductivity,Thermal response test (TRT)
更新于2025-09-23 15:21:01
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Combinations of heat pump and photovoltaics for renovated buildings
摘要： The aim of this work is the analysis of hybrid heating systems consisting of an air source heat pump, a storage tank and a photovoltaic (PV) system for the use in renovated residential buildings. The potential for decreasing the electrical energy consumption of the heat pump from the grid by targeted operation of the speed controlled compressor with electricity from PV is determined by means of dynamic system simulations in TRNSYS for a renovated single family house under the assumption that the existing radiator heating system is not replaced, and that therefore relatively high supply temperatures are necessary. Different variants were considered with regard to the size of the PV system, the storage volume and the influence of the heat emission system.
关键词： hybrid heating systems,photovoltaics,TRNSYS,renovated buildings,heat pump
更新于2025-09-19 17:13:59
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Performance assessment of a hybrid photovoltaic-thermal and heat pump system for solar heating and electricity
摘要： This work investigates a solar combined heat and power systems based on hybrid photovoltaic-thermal heat pump systems for the simultaneous provision of space heating and electricity to residential homes. The analysed system connects a photovoltaic-thermal (PVT) panel, through a PVT water tank, to a heat pump. The study is based on quasi-steady state heat transfer and thermodynamic analysis that takes incremental time steps to solve for the fluids temperature changes from the heat pump and the solar PVT panels. The effects of solar irradiance, size of the water tank and the water flow rate in the PVT pipes (laminar and turbulent) on the performance of the system are analysed. Particular focus is made towards the efficiency (electrical and thermal) of the PVT and the COP of the heat pump. Results show that the minimum COP of the heat pump is 4.2, showing the high performance of the proposed hybrid system. Increasing the water flowrate through the PVT panel from 3L/min (laminar) to 17L/min (turbulent) increases the PVT’s total efficiency (electrical + thermal) from 61% to 64.5%. Increasing the size of the PVT water tank from 1L to 100L, increases the total efficiency of the PVT panel by 6.5%.
关键词： quasi-steady state modelling,heat pump,solar photovoltaic-thermal,hybrid system
更新于2025-09-19 17:13:59
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Proposal and performance analysis of a novel solar-assisted resorption-subcooled compression hybrid heat pump system for space heating in cold climate condition
摘要： Absorption-resorption heat pumps (ARHPs) can efficiently utilize low-temperature solar heat for winter space heating, but are restricted by the relatively weak low ambient temperature adaptability. By combining the different strengthens of vapor compression heat pump (VCHP) and absorption-resorption heat pump (ARHP), a novel solar-assisted resorption-subcooled compression hybrid heat pump system with higher heating capacity under cold climate condition for space heating is proposed. Thermodynamic models for the hybrid system involving two subsystems are developed for performance evaluation under different operation conditions. Feasible high pressure/low pressure (PH/PL) and evaporation temperature/condensation temperature (Te/Ta) ranges for the hybrid system are revealed for component design. Based on that, performance evaluation indices like total coefficient of performance (COPtot), primary energy ratio (PER), primary energy saving ratio (PESR), coefficient from solar irradiation to heating capacity (SCOP) are investigated in terms of different PH/PL and Te/Ta values. The results showed that for the base-case, the above indices are 2.41, 1.66, 0.35 and 1.21, respectively. In addition, heat source temperature demand, heating capacity and ambient air temperature need of the hybrid system are compared with those of the conventional absorption heat pump (AHP), single ARHP and single VCHP under the same operation conditions. The results show that the hybrid system can extend the operation heat source temperature to above 72 oC, highlighting the possibility of integrating with common non-tracking solar collectors, and can extend the feasible ambient air temperature to above -20 oC. Moreover, by recovering the sub-cooling heat of VCHP subsystem for ARHP subsystem operation, the hybrid system can lift the heating capacity by over 50% based on the equivalent VCHP system.
关键词： cold climate condition,resorption-subcooled,solar-assisted,hybrid heat pump,space heating
更新于2025-09-19 17:13:59
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Performance indicators of photovoltaic heat-pumps
摘要： In the last few decades, the demand for reversible heating and cooling systems has increased significantly, together with the need to generate energy in a more efficient and sustainable way. Consequently, the concept of solar photovoltaic (PV) powered heat pumps (HP) has become very attractive in order to match the heating/cooling demand with a renewable and environmentally-friendly energy source. This paper presents a review of the different solutions for PV-HP systems that have been studied theoretically and/or experimentally tested, and of the Key Performance Indicators (KPIs) that were mainly used. An analysis of these traditional KPIs has been performed and their boundaries were identified. As a result, new KPIs (PR25, PRref,25, SPFPV-HP and SPFPV-HP,ref,25) were proposed for trying to mitigate such limitations, as well as for evaluating not only the quality of the HP and the PV system, but also the quality of their integration and the renewable character of the whole PV-HP system. This paper is aimed to be framed in the common effort of the PV-HP research community to reach a set of KPIs that allow comparing the different future works and, therefore, a set of recommendations and future research lines are also proposed.
关键词： Heat-pump,Performance indicator,Photovoltaic,Electrical engineering,Energy engineering,Engineering,Photovoltaic/Thermal,Systems engineering,Industrial engineering
更新于2025-09-19 17:13:59
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Performance enhancement of a photovoltaic thermal (PVT) and ground-source heat pump system
摘要： A new system consisting of photovoltaic thermal-ground source heat pump (PV/T-GSHP) was proposed as a solution for electricity shortage and high electricity consumption in heating buildings in Jordan. The performances of the photovoltaic system and the ground source heat pump system were studied without coupling as in real life and with coupling in a hybrid system using TRNSYS software. The results show that this PV/T-GSHP hybrid system can reduce the photovoltaic panels' temperature by more than 20 °C, and improve the e?ciency of electricity production by 9.5 %, simultaneously. And in heating season the average coe?cient of performance of the heat pumps increased from 4.6 to 6.2 with a decreament in electricity consumption by 25.7 %. The life cycle cost of the hybrid system decreased by 3.9 % and the net present value inceased by 13.2 % compared to the two systems separated. The model of the PV/T-GSHP system was established using TRNSYS software, an optimmi-zation was made to select the photovoltaic modules' temperature at which cooling starts, followed by technical and economical studies on both systems separated and coupled in a hybrid system. This hybrid system can provide guidance for future related project.
关键词： Hybrid system,Ground-source heat pump,TRNSYS,Renewable energy,Solar photovoltaic/thermal
更新于2025-09-19 17:13:59
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Effect of dust deposition on performance characteristics of a refrigerant based photovoltaic/thermal system
摘要： A photovoltaic/thermal (PV/T) system is an integration of a solar thermal system and photovoltaic module, which produces both heat and electricity simultaneously with better performance characteristics. Depending on the heat transfer fluid employed, they are mainly classified as air, water or refrigerant based systems. Advances in the field of PV/T systems ascertained that refrigerant based PV/T systems have better reliability and superior performance compared to air or water based PV/T systems. To date, the effect of dust deposition on the performance of a refrigerant-based photovoltaic/thermal system is hardly reported. The objective of the present study is to analyze the effect of dust deposition on the performance characteristics of a refrigerant photovoltaic/thermal system. Firstly the dust deposition under the climatic conditions of Surat City (21.17° N, 72.83° E), India was characterized through an experimental procedure following which a validated numerical model was used to study its effect on performance. It was observed that the progressive dust accumulation for a period of eight weeks reduced the spectral transmissivity of the glass from 91% to 46.09% due to which the electrical efficiency and coefficient of performance (COP) of the system reduced relatively by 44.14% and 8.53% respectively.
关键词： Dust deposition,Photovoltaic/thermal system,Heat pump
更新于2025-09-16 10:30:52