Solar Trigeneration System Research Articles

Cost-Optimality Assessment of a Solar Trigeneration System for Tertiary Sector Buildings in Greece

To pave the way towards buildings’ decarbonization in the context of the European Union’s (EU) policy, the methodology of cost-optimality assessment based on regulation 244/2012/EU is a useful tool to explore and foster the application of energy technologies in buildings. Meanwhile, the fostering of concentrated solar power is included in the EU solar energy strategy. In this study, the cost-optimal methodology is employed for the techno-economic assessment of the integration of a novel solar, multi-purpose energy technology, namely a parabolic trough collector-based trigeneration system, in two building types with different characteristics, namely an office and a hospital, in Greece, thus allowing the evaluation of the cost-optimal system design and the impact of the building type on the system’s techno-economic performance. Reference buildings are defined and their energy demand is calculated through dynamic energy simulations. The trigeneration system’s performance for different design scenarios is then parametrically investigated using a simulation model. For each scenario, energy, environmental and economic indicators are calculated and the cost-optimal designs are extracted. In the cost-optimal implementation, the system covered 18.19–36.39% and 3.58–15.71% of the heating and cooling demand, respectively, while the reduction of the primary energy consumption and emissions was estimated at 10–14% and 10–16%, respectively. However, differences between the buildings related to the operation schedule and the loads led to the implementation of the system being economically more attractive in the hospital, while for the office, financial support is necessary for a viable investment.

4E analysis of photovoltaic thermal collector-based tri-generation system with adsorption cooling: Annual simulation under Moroccan climate conditions

Using solar photovoltaic thermal technology for tri-generation systems has gained increased interest. However, there is a dearth of literature on the assessment of this solar system integrated with adsorption chiller from a holistic 4E perspective. Hence, energy, exergy, economic and environmental analyses are performed along with sustainability assessment in Moroccan regions.The results revealed that the solar tri-generation system exhibited a promising performance, especially in hot desert region, achieving an energy efficiency of 50.07% due to the high insolation. The exergy analysis proved superior energy production quality in cold Mediterranean region, with an exergy efficiency of 15 %. Economically, the system could be considered cost-effective with a levelized cost of production reaching $0.074/$0.059 per kWh and a discounted payback period of 17.31/15.12 years in cold Mediterranean/hot desert regions. Moreover, in hot desert region, the system could mitigate 3.46 tCO2/m2 of solar collector, while in cold Mediterranean region it exhibits the best sustainability index of 1.18 due to high-quality energy production.Overall, the paper emphasizes the need for further research and advancement of this technology for a sustainable environment. Besides, it aims to offer engineers and researchers valuable insights into the potential of photovoltaic thermal-based tri-generation systems, especially in the building sector.

Techno-economic-environmental decision-making approach for the adoption of solar and natural gas-based trigeneration systems

Trigeneration systems have the ability to mitigate greenhouse gas emissions as well as result in cost savings, especially in high utility-cost markets. However, sometimes decision-making to adopt a trigeneration system can be complicated due to variations in load demand profiles and locations. The present paper is aimed at developing a generalized decision-making framework to estimate the optimal sizing as per diverse hourly building loads as well as the economic and environmental viability of natural gas and solar-based trigeneration systems. Unlike the existing literature, the decision-making approach has been demonstrated on eight different building types in five North American locations with high utility cost and rebates. EnergyPlus is used to determine the yearlong hourly energy demand of different buildings and then incorporate demand profiles to develop various sizing scenarios. To assist decision-making, economic criteria are proposed based on utility-rate structures to estimate payback periods and use the levelized cost of energy (LCOE) analysis. Incorporating environmental analysis in the decision-making process, location-specific utility scale emissions and emissions from trigeneration systems are considered. For solar-based trigeneration systems, the max area sizing scenario is found to be advantageous for buildings with higher ground-to-floor area ratios (i.e., supermarkets and secondary schools). However, for natural gas-powered trigeneration systems, two sizing scenarios are proposed (i.e., electricity sizing and heat sizing), and multiple micro-combined heat and power units are found to be preferable for various building applications. Solar trigeneration systems offered the fastest payback in vertical farms, and hospitals (the average varies from 5.4 to 9.0 years), while natural gas-based trigeneration systems had the best payback in hospitals, vertical farms, and secondary schools (the average varies from 5.7 to 8.1 years). The environmental performance of the trigeneration system varied based on the building and location combinations, thus decision-making is strongly influenced by grid greenhouse gas emissions. The proposed decision-making method can be generalized and applied to other locations to determine the most viable building applications for solar and natural gas-based trigeneration systems.

Energy analysis of a novel solar tri-generation system using different ORC working fluids

A novel solar tri-generation system combined with an Organic Rankin Cycle (ORC), humidification dehumidification water desalination system (HDH), and a desiccant cooling system (DCS) for electrical power generation, water desalination, and air-conditioning is investigated numerically. Such a system is intended for tiny and medium-sized structures in Gulf nations that are abundant in solar energy but deficient in fossil fuels and water supplies. Detailed parametric studies of the operating and design parameters on the system's productivities and performance are carried out using different kinds of organic fluids (n-Octane, R245fa, R113, R123, Cyclohexane, and Toluene). It is noticed that the proposed system can provide the highest electrical power, fresh water, and space cooling capacity of 152.5 kW, 77.29 kg/s kg/h, and 27.11 kW, respectively, using Cyclohexane. Moreover, the maximum energy utilization factor obtained is 0.3018 using R123 and the improvement percentage of using R123 instead of n-Octane is 20%. Finally, general numerical correlations of a system's productivities and its performance are developed and presented within reasonable errors for different organic fluids.

Investigating the hybridisation of micro-scale concentrated solar trigeneration systems and wind turbines for residential applications using a dynamic model

Solar and wind energy sources are envisioned to play a key role in the transition towards fully renewable energy systems but both suffer from their intermittent nature, which can be relieved by hybridisation. Hence, the benefits of the complementarity of these sources are investigated hereunder by considering a small-scale hybrid trigenerative system consisting of a Linear Fresnel Reflector solar field with a 440 m2 collector area, a 20 kWe/100 kWt organic Rankine cycle unit combined with a latent heat thermal energy storage system, an absorption chiller, and a 20 kWe wind turbine for the provision of electricity, heating and cooling to 10 residential apartments. To this end, a dynamic model and suitable control logic are developed to assess and compare the performances of the proposed hybrid system concerning the solar plant and wind turbine separately.The results show that hybridisation can extend the annual thermal coverage by renewables by 3.7–6.1% for the investigated locations by increasing the operation of the organic Rankine cycle unit, especially in winter. In particular, the surplus electrical energy from the wind turbine is used to satisfy 6% and 4% more than the separate configuration of the annual thermal and electrical demands for Ancona. As a result of hybridisation, the annual thermal energy consumption of the boiler reduces by 8.3%, 9.9%, and 37.6% for Perugia, Ancona, and Messina respectively, which shows the impact of the profile of the energy sources. At the same time, hybridisation improves grid stability by reducing the excess electricity production 18.2%, 19.2%, and 26.3% for Perugia, Ancona, and Messina respectively.A sensitivity analysis for Ancona has revealed that the size of the water thermal energy storage tank does not have a significant impact on the electrical and thermal coverage of the hybrid system, while electrical and thermal coverages improve 11.1% and 6.7% respectively by doubling the wind turbine capacity along with a 14.8% drop in the thermal energy consumption by the boiler. In brief, the analysis has shown the complementarity of these energy sources and the benefits of hybridisation for trigenerative systems for residential buildings.

Photovoltaic parameter extraction and optimisation of ZnO/GO based hybrid solar trigeneration system using SCAPS 1D

In this work, simulative investigation of Zinc Oxide/Graphene Oxide based novel hybrid solar trigeneration system has been performed to identify its photovoltaic parameters i.e. Current density (Jsc), Open circuit voltage (Voc), fill factor (FF), Power Conversion Efficiency (PCE), using SCAPS 1D (Solar Cell Capacitance Simulator) software. A comparison was made between the simulated and estimated experimental values for the cell under standard test conditions, which showed an all over good agreement. The simulated values of VOC, JSC, FF, PCE for ZnO/GO are 0.79 V, 12.46 mA/cm2, 52.14 %, 8.46 % respectively. The extracted experimental values are 0.72 V, 7.24 mA/cm2, 56.94 %, 9.12 % respectively. Further analysis is done to study the effect of graphene oxide layer thickness on PV properties of the cell. Also performance of ZnO/GO cell was compared to ZnO/SiO2 cell and it was found that the efficiency of the two is nearly similar when evaluated at 32 °C under 1 Sun and AM 1.5. A limiting factor in using the high-efficiency Si homojunction solar cell is its high fabrication cost. Hence here we try to replace GO with SiO2 because of its simpler synthesis and involved fabrication processes. But the only backdrop is its lower efficiency, which can be improved by rigorous simulation analysis of the organic semiconductor layer. The performance of the presented hybrid system has been estimated and differentiated with other known solar trigeneration system to evaluate the viability of the showcased model, provided physical constraints imposed by the environment are considered depending upon the system installation location.

Thermodynamic analysis and multi-objective optimization of a modified solar trigeneration system for cooling, heating and power using photovoltaic-thermal and flat plate collectors

Most solar polygeneration systems use a single solar source to power the system. Despite their importance, dual-source systems received less attention. To address this gap, this study aims to analyze a new polygeneration arrangement that combines photovoltaic thermal (PVT) and flat plate collector (FPC). A detailed thermodynamic and economic analysis is conducted for a newly designed cooling, heating, and power (CCHP) system powered by solar energy for domestic applications. PVT and FPC collectors, with an ejector-vapor-compression refrigeration cycle that is equipped with a booster compressor, are used in the proposed system. The key goal of using a PVT with FPC panel in a series configuration is to achieve maximum electrical and thermal efficiencies. The effects of various factors on the system performance, including booster pressure ratio, R600a, and R290 refrigerants, PVT-FPC cycle water flow rate, and solar irradiation, are investigated. The multi-objective optimization results show that energy and exergy efficiency, payback period, and internal rate of return are 90.15%, 12.46%, 4.025years, and 26.67%, respectively. The results showed that using a booster compressor significantly increases the system performance by 96.34% in coefficient of performance (COP), 55.1% in exergy efficiency, and 121.9% in net output power. This optimum system also prevents the release of 2504 kg of carbon dioxide into the environment.

Solar preheat with significant Thermodynamics Parameter Scrutiny of Energetic, Economic and Environmental Analysis in Tri-generation System.

The solar tri-generation system can enhance the use of solar energy in residences. In this paper, an evaluation of the performance and operating parameters of an absorption sub-cooled compression hybrid cooling (ASCHC) configuration based on the pairing of photovoltaic thermal (PVT) collectors is presented. The work includes the multi-culmination fractionation and chiller originator to the Natural Rankine sequence system to evaluate the critical thermodynamic parameters such as irreversibility ratio, fuel depletion ratio, improvement potential, and total exergy loss of the system. The study was carried out using the first law and second law of thermodynamics applied to each component of each system. Solar absorption-subcooled compression hybrid cooling system (SASCCHC) is a novel cooling system that consistently meets the demand of cooling load with solar irradiance change. It is a very efficient and economical solar cooling system. The hybrid system’s performance is higher due to the improvement of the evaporator temperature of the absorption subsystem. However, SASCCHC is complicated in terms of working process and performance simultaneously due to the coupling of the absorption and compression subsystems. In the prior methodologies, there is a lack of electrical output performances of PVT collectors. It is found that previous studies do not consider the changeable storage tank temperature, exergy destruction rate estimation, and scrutinizing of thermodynamic parameters, which are significant potential. The present work incorporates the parabolic channel collector to estimate the exergy destruction rate, which increases the output working fluid temperature to a wide range significantly. Due to this, the proposed analysis’s outcome proficiently increases fuel depletion ratio and decreases exergy loss.

Optimization and Comparison of Photovoltaic Parameters of Zinc Oxide (ZnO)/Graphene Oxide (GO) and Zinc Oxide (ZnO)/Carbon Quantum Dots (CQDs) Hybrid solar cell using Firefly Algorithm for application in Solar Trigeneration System in Commercial Buildings

Solar cells formed by the combination of organic and inorganic nanoparticle semiconductors are gaining interest in today’s era because of their major features, such as being suitable for scalable solar power conversion and being of low cost to produce desirable photovoltaic devices. This work is an attempt to develop two forms of hybrid solar cells, one by the amalgamation of zinc oxide and carbon quantum dots and second, by incorporating graphene oxide into zinc oxide. In this study, optimization, validation, and comparison of the photovoltaic parameters of the two nanostructured solar cells were attempted using the Artificial Neural Network technique. The ANN was instructed using the Firefly Algorithm. The input parameters are the spectral power density and temperature. The output parameters are the short circuit current (ISC), open-circuit voltage (VOC), fill factor of the cell (FF), and maximum voltage point prediction (VMPP). The results obtained for both the hybrid solar cells were compared and it was noted that the addition of CQDs to ZnO resulted in a considerable increase in the values of ISC, VOC and FF. The output obtained by the ANN trained model was compared with the results obtained from the experimental tests. It is observed that there is considerable agreement between the results obtained from the ANN and experimental values. The optimized values of VOC, ISC, FF, VMPP, Incident Photon to Current Efficiency (IPCE), Power Conversion Efficiency (PCE) for ZnO/GO are 0.623 V, 0.546 mA, 62%, 0.509 V, 36.95%, 9.12% respectively. Similarly values of VOC, ISC, FF, VMPP, IPCE, PCE for ZnO/CQDs are 0.636 V, 0.597 mA, 68%, 0.531 V, 40.72%, 10.35% respectively. Therefore, the precise values of all the stated parameters were obtained for both the cells after optimization and hybrid cells made of CQDs proves to be a better candidate. Also, the desirable value of the coefficient of correlation (R) is obtained, approximately close to 1, which means that the fabricated samples are efficient for useful applications. Proper execution of this algorithm on any model of the hybrid solar cell can lead to an evolution in the field of solar cells, resulting in the improvement of efficiency. These optimized cells have been utilized to propose two models of solar trigeneration system used in a commercial building North Service Centre (Olefin building) of Haldia Petrochemicals Limited, Haldia, West Bengal, India. The trigeneration systems were based on photovoltaic modules, heat pump and photovoltaic-thermal collectors. The objective is to provide enough electricity, domestic hot water, heating and cooling power to meet the typical demand of a single office building. System performance has been predicted and evaluated in the work. Considerations should be made regarding the physical constraints imposed by the environment where the installation has to be performed. The location should be carefully selected to achieve maximum efficiency.

Assessment and parametric analysis of solar trigeneration system integrating photovoltaic thermal collectors with thermal energy storage under time-of-use electricity pricing

The solar trigeneration system based on coupling photovoltaic thermal (PVT) collectors with an absorption-subcooled compression hybrid cooling configuration has the potential for enhancing solar energy utilization in buildings. Considering time-of-use electricity pricing, the availability of solar cooling often does not coincide with on-peak periods during which electricity prices are high. To benefit from time-of-use pricing for greater economic profitability, sensible heat thermal storage is potential options. However, changeable storage tank temperature affects not only solar cooling capacity but also the electrical output of PVT collectors. Thus, in this work, three operation schemes (i.e., a conventional scheme, heat energy storage and cool energy storage schemes) are compared, and the effect of key design parameters on system performance is analyzed. Models for different system layouts and a conventional photovoltaic (PV-only) system are developed by programming with MATLAB. Annual (8760-hour) simulations are performed based on a case study for a high-rise hotel in subtropical cities. The results for Guangzhou show that the system layout, integrating cool energy storage and glazed PVT collectors with low-emissivity coatings, achieves the highest total electricity cost saving, which is 16% higher than that of the PV-only system. Its total solar energy utilization efficiency is 0.321, which is 2.4 times that of the PV-only system. The novelty of this work is that it provides an appropriate energy storage strategy and the design guidelines of key parameters for PVT-based solar trigeneration systems. This work is helpful for PVT-based solar trigeneration systems to improve operating cost savings under time-of-use electricity pricing.

Comprehensive evaluation of low-grade solar trigeneration system by photovoltaic-thermal collectors

Solar trigeneration systems based on photovoltaic-thermal collectors can play a positive role in promoting renewable energy integration in buildings. Usually, low-grade solar heat produced by photovoltaic-thermal collectors does not meet the temperature requirement for driving absorption chillers, leading to unsatisfactory system performance. In this study, the solar absorption-subcooled compression hybrid cooling system, which is capable of utilizing heat at temperatures as low as 60 °C, is coupled with photovoltaic-thermal collectors to be a low-grade solar trigeneration system. In spite of heat recovery for heating and cooling, the electrical output of collectors decreases, due to the losses caused by the additional glass cover and elevated operating temperature. Therefore, through quasi-steady simulations based on annual meteorological data of three subtropical cities, this system is assessed from energy, economic and environmental viewpoints. The results show that in Guangzhou, the specific annual electricity saving of this system is up to 170.6 kWh/m2, which is 17.3% higher than that of a comparable photovoltaic system. The parametric analysis suggests that increasing the solar filed area gives rise to a shorter payback period. With the maximum available solar filed area of 600 m2, the minimum payback period and the maximum electricity saving can be achieved by the absorption subsystem capacities of around 40 kW and 180 kW, respectively. The most economically viable system is obtained in Zhuhai where annual solar irradiation is close to 1400 kWh/m2 and electricity prices are relatively high. This study is useful for the development of solar trigeneration systems based on photovoltaic-thermal collectors and energy saving in modern cities.

Comparative analysis of a solar trigeneration system based on parabolic trough collectors using graphene and ferrofluid nanoparticles

In this comparative study, the thermodynamic analysis of a trigeneration system driven by a parabolic through solar collector based on two different types of nanofluid is performed. A standard trigeneration system consists of two subsystems, including an absorption heat pump and the organic Rankine cycle. Two types of nanoparticles (graphene and ferrofluid) that possess excellent and diverse physical properties within a base fluid (Syltherm 800) were selected to be the absorption fluids in the solar cycle. Four organic fluids, namely R123, R401a, R601, and R601a, for the organic Rankine cycle are examined. The results clearly depicted improvement in the system performance. It was found that graphene nanoparticles performed better as compared to the ferrofluid nanoparticles. The largest temperature of the collector outlet was obtained at 257.4? with Syltherm 800/graphene. The highest net power produced by the system was 134.1 kW and the maximum overall energy and exergy efficiencies of the system were 160.5% and 21.84%, respectively. The highest net power produced by the system was 134.1 kW and the maximum overall energy and exergy efficiencies of the system were 160.5% and 21.84%, respectively. The solar collectors are the main source of the exergy destruction and the highest value was recorded about 683 kW.

Energy and exergy analysis and optimum working conditions of a renewable energy system using a transient systems simulation program

A solar tri-generation system comprises of photovoltaic thermal collectors that are used for the production of electrical power and domestic hot water simultaneously. This study presents the performance analysis of a micro-solar tri-generation system that fulfills the requirements of an off-grid single-family lodging. The main functions of this system include domestic hot water, electrical power, and cooling power production. A set of five photovoltaic thermal panels were modeled together. The electrical power generated was stored in a battery, while the hot water generated was passed through a flow diverting valve. This valve directed some of the hot water to an absorption chiller, while the remaining portion was sent to an insulated thermal storage tank for later use. Energy and exergy analyses were performed to evaluate the extracted energy’s quality and efficiency. The overall thermal energy efficiency achieved was 50.53%. The extracted energy in the form of hot water was 3777.5 W. The electrical power generated was 2984.6 W, which was sufficient for the small single-family lodging. The coefficient of performance of the absorption chiller was found to be 0.6152. The exergy efficiency achieved was 36.88%. The exergy extracted by hot water was 234.3 W, while the electrical exergy generated was 2984.6 W. The exergy extracted during refrigeration was found to be 91.22 W. Furthermore, varying wind speeds and tilt angles affected both the energy and exergy efficiencies. The tilt angle must be kept at less than 45°, and the optimum wind speed was determined to be 35 km/h.

A novel integrated solar tri-generation system for cooling, freshwater and electricity production purpose: Energy, economic and environmental performance analysis

This article presents the results of a thermodynamic-economic-environmental analysis of integrating linear Fresnel reflector (LFR) with a tri-generation system. The optimal integrated solar field size has been identified and the pertinent reduction in CO2 emissions due to solar integration is estimated. For the considered tri-generation plant (that is required to produce 110 MWe of electricity from steam turbines, 45461 m3/day of freshwater and 2300 kg/s of chilled water), the study revealed that the optimal configuration is the integration of 83.6 hectares of LFR solar field with the tri-generation plant of 130 MWe, which gives a levelized electricity cost of 6.37 USȻ/kWh with 96.40 k-tonne reduction of the annual CO2 emission. The study also revealed that the integration of LFR technology with a conventional tri-generation system (TGS) in high insolation regions has more economic feasibility compared to equivalent TGS integrated with CO2 capturing technology while achieving the same emissions reduction result.

Thermodynamic analysis of a novel solar trigeneration system

Loop heat pipes (LHPs) are high efficiency devices which can be used in solar systems. The main objectives of this research are to propose a novel solar combined cooling heating and power (SCCHP) system based on loop heat pipe (LHP) evaporator, and to present thermodynamic analyses to effectively improve the utilization of loop heat pipes for distributed renewable energy sources. Also a parametric analysis is carried out to investigate the effect of the key variable parameters on the system performance for three operation modes (solar mode, solar and storage mode and storage mode). The results showed that, for the solar and solar and storage operation modes, the main source of the exergy destruction is the solar loop heat pipe evaporator while for the storage operation mode, the main source of the exergy destruction is the hot storage tank. The energy efficiency of the proposed system is 70.52% for the solar mode, 72.09% for the solar and storage mode, and 64.77% for the storage mode and the exergy efficiency of the proposed system is 12.36% for the solar mode, 14.78% for the solar and storage mode, and 47.45% for the storage mode.

Techno-economic analysis of solar trigeneration system

In this work, a techno-economic analysis of concentrated photovoltaic/thermal collector (CPVT) driven desalination and cooling plant is presented. The system comprises of a CPVT collector, a humidification-dehumidification (HDH) desalination unit and vapour compression refrigeration (VCR) unit. The CPVT collector having 10 m2 aperture area and a triple junction PV panel placed at the receiver supplies required hot water to the HDH desalination system. Chilled water generated from 0.5 hp compressor operated VCR unit is supplied to the dehumidifier of HDH desalination. The process of cooling and dehumidification using chilled water result in increased desalination yield and resulting air is suitable for air conditioning purpose. The work is aimed to evaluate the annual performance of the trigeneration plant and to estimate the unit cost of fresh water and payback period. The annual performance of the plant is evaluated for the typical metrological year data for the location of Vellore, India. Results show that the annual desalination, electricity and cooling output are 4.2 m3/yr and 3.46 MWh/yr and 0.788 MWh/yr respectively. The daily average desalination and cooling output are 11.12 L/day and 2.47 kWh/day respectively. The annual electricity consumption of the solar cogeneration plant is 6570 kWh/yr. The estimated unit cost of fresh water is ¹10/L. By considering the interest rate of 9 % and total life time of the plant as 20 years, the payback period is estimated to be 6.5 years.

Evaluation and comparison of solar trigeneration systems based on photovoltaic thermal collectors for subtropical climates

Solar trigeneration systems based on photovoltaic thermal (PVT) collectors are promising for enhancement of solar energy utilization. Single-effect LiBr-H2O absorption chillers are usually employed in these systems. Since the temperature of solar heat from PVT collectors is low, half-effect absorption chillers are potential alternatives for performance improvement. However, the coefficient of performance (COP) of half-effect absorption chillers is lower than that of single-effect machines. Therefore, the comparison of solar trigeneration systems with both types of chillers is necessary. Four different system layouts, obtained by coupling glazed and unglazed flat-plate PVT collectors with single- and half-effect absorption chillers, are modeled. Annual (8760-hour) simulations are performed to evaluate and compare the thermodynamic and economic performances of different layouts. The results show that the system layout based on glazed PVT collectors coupled with half-effect absorption chillers achieves the highest Solar COP of 0.072 and the highest solar utilization factor of 0.241. Its specific electricity saving is 158.5 kWh/(m2·year), the highest among all the layouts. Additionally, the payback period of the layout based on unglazed PVT collectors coupled with half-effect absorption chillers is 12.7 years, the lowest among all the layouts. This paper is helpful for the development and design of solar trigeneration systems based on PVT collectors in subtropical climates.

Evaluation of a solar driven trigeneration system with conventional and new criteria

ABSTRACTSolar-driven trigeneration systems are able to cover all the building energy needs in heating, cooling and electricity using only the solar energy. The objective of this paper is to evaluate a solar trigeneration system under different criteria in order to make clear that there are numerous factors which have to be taken into consideration in the trigeneration system design. The examined system consists of parabolic trough solar collectors, a storage tank, an organic Rankine cycle and an absorption heat pump. The system is evaluated using different evaluation criteria which are associated with the energy, the exergy and the financial performance of the system. Moreover, a new criterion which takes into account the building energy needs is introduced and is investigated in different scenarios. The final results of this work clearly indicate that the optimisation of the solar driven trigeneration systems is depended on the desired design conditions and goals.Abbreviations: COP, Coefficient of performance; ECO, Economizer; EES, Engineering Equation Solver; EVAP, Evaporator; ORC, Organic Rankine Cycle; PTC, Parabolic trough collector; SC, Scenario

Parametric analysis of a solar Organic Rankine Cycle trigeneration system for residential applications

In this paper, the potential of a small scale concentrated solar Organic Rankine Cycle unit coupled with an absorption chiller for trigeneration purposes is investigated using a simulation analysis.At the moment, only few research works encompass small-scale solar trigeneration systems and most of them do not refer to real plant. On the contrary, in this work electric, heating and cooling maximum generation of a real and experimental small scale prototype system composed of a 50 m2 CPC solar field, a 3.5 kWe ORC plant and a 17 kWc absorption chiller is investigated by means of TRNSYS. In particular, this work relies on the evaluation of the dynamic performance of the mentioned plant varying some selected system parameters to provide proper modifications of its design configuration and operation.More precisely, working temperature ranges, heating and intermediate fluid flow rates as well as volume of the storage tanks and size of the solar field have been varied within the simulation model. Results have shown that operating temperature ranges of the storage tanks considerably affect the overall performance of the system; by appropriately choosing these ranges the primary energy production can be increased by 6.5% compared to the baseline configuration without any additional investment costs. Moreover, setting suitably some design parameters can significantly contribute to extend the operating hours and the feasibility of a such small scale integrated system for residential applications.

Performance assessment of a solar trigeneration system for residential applications by means of a modelling study

Concentrated solar technologies coupled with ORC system is a well-known topic in temperature ranges lower than 200°C. However, the integration to an efficient and economic working system is still a challenge especially at small scale. Efforts exist to achieve higher overall efficiencies but they are solely focused on thermal and electrical production while few of these is encompassing small-scale solar trigeneration systems. In the present article, the potential of a small scale concentrated solar Organic Rankine Cycle plant coupled with an absorber is investigated using a simulation analysis of a small scale 50 m2 CPC solar field, a 3.5 kWe ORC and a 17.6 kWc absorption chiller to satisfy respectively heating, electricity and cooling needs of a residential user. The simulation analysis of the overall system has been carried out in TRNSYS and an own model of the ORC system has been developed by the authors in Matlab thus improving the previous general model. The final aim of the proposed work is indeed the performance assessment of the small scale integrated system in order to evaluate the potential feasibility of such a system for residential applications.