Publications
30 results found
Roy D, Zhu S, Wang R, et al., 2024, Techno-economic and environmental analyses of a solar-assisted Stirling engine cogeneration system for different dwelling types in the United Kingdom, Energy Conversion and Management, Vol: 302, ISSN: 0196-8904
In this study, a hybrid cogeneration system that combines photovoltaic-thermal (PV-T) collectors with a Stirling engine, and a battery-pack-based energy option is proposed for residential applications. The system’s purpose is to fulfil the electrical and heating requirements of different types of houses in the United Kingdom, including detached, semi-detached and mid-terraced houses. This study includes a comprehensive assessment of the techno-economic feasibility and environmental impact of the proposed integrated energy system, after determining the appropriate sizing of the system’s components for the three different house types. The exergy efficiency of the integrated system for detached houses (with a 1 kWe-Stirling engine plus 28 m2 of PV-T collector array) is found to be higher compared to that for the semi-detached and mid-terraced house configurations, with the highest efficiency of 22 %. In terms of economic performance, detached houses have the lowest levelized cost of electricity (0.622 £/kWh), levelized cost of heat (0.147 £/kWh), and levelized cost of total energy (0.205 £/kWh). Furthermore, the system demonstrates the maximum potential reduction in CO2 emissions in detached houses. The achieved CO2 emissions reduction rates for different house configurations fall within the range of 30 % to 45 %. The proposed hybrid cogeneration system shows promise as an effective and sustainable solution to meet the energy demands of various residential house types in the United Kingdom, offering improved efficiency, cost-effectiveness, and substantial reductions in carbon emissions for detached houses.
Herrando M, Wang K, Huang G, et al., 2023, A review of solar hybrid photovoltaic-thermal (PV-T) collectors and systems, Progress in Energy and Combustion Science, Vol: 97, Pages: 1-74, ISSN: 0360-1285
In this paper, we provide a comprehensive overview of the state-of-the-art in hybrid PV-T collectors and the wider systems within which they can be implemented, and assess the worldwide energy and carbon mitigation potential of these systems. We cover both experimental and computational studies, identify opportunities for performance enhancement, pathways for collector innovation, and implications of their wider deployment at the solar-generation system level. First, we classify and review the main types of PV-T collectors, including air-based, liquid-based, dual air–water, heat-pipe, building integrated and concentrated PV-T collectors. This is followed by a presentation of performance enhancement opportunities and pathways for collector innovation. Here, we address state-of-the-art design modifications, next-generation PV cell technologies, selective coatings, spectral splitting and nanofluids. Beyond this, we address wider PV-T systems and their applications, comprising a thorough review of solar combined heat and power (S–CHP), solar cooling, solar combined cooling, heat and power (S–CCHP), solar desalination, solar drying and solar for hydrogen production systems. This includes a specific review of potential performance and cost improvements and opportunities at the solar-generation system level in thermal energy storage, control and demand-side management. Subsequently, a set of the most promising PV-T systems is assessed to analyse their carbon mitigation potential and how this technology might fit within pathways for global decarbonization. It is estimated that the REmap baseline emission curve can be reduced by more than 16% in 2030 if the uptake of solar PV-T technologies can be promoted. Finally, the review turns to a critical examination of key challenges for the adoption of PV-T technology and recommendations.
Herrando M, Fantoni G, Cubero A, et al., 2023, Numerical analysis of the fluid flow and heat transfer of a hybrid PV-thermal collector and performance assessment, Renewable Energy, Vol: 209, Pages: 122-132, ISSN: 0960-1481
In recent years, new materials and absorber configurations have been proposed to improve the performance of hybrid photovoltaic-thermal (PV-T) collectors. This work analyses the fluid flow and the energy performance of an uncovered water-based PV-T collector with a roll-bond thermal absorber. A detailed CFD model was developed and the results were compared with the experimental performance features provided by the PV-T manufacturer. The fluid flow results show uneven flow distribution among the roll-bond microchannels which leads to areas with larger PV cell temperatures and thus a lower electricity generation. The PV-T collector layers were also modelled using the energy transfer equations layer-by-layer. The model was run for several water inlet temperatures and water flow-rates to obtain the thermal performance curve. The results show that the electrical efficiency of the PV-T collector is 14.5–10.3% larger than for a PV-only system for water inlet temperatures of 20–30 °C, respectively. The developed CFD model reproduces accurately the thermal performance of the PV-T collector, with a maximum error of 6.5% for inlet water temperatures of 20–60 °C. Therefore, this model can be used with confidence to propose alternative designs that achieve a homogeneous temperature distribution in the PV layer and improve the overall PV-T collector performance.
Herrando M, Coca-Ortegon A, Guedea I, et al., 2023, Experimental validation of a solar system based on hybrid photovoltaic-thermal collectors and a reversible heat pump for the energy provision in non-residential buildings, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, Vol: 178, ISSN: 1364-0321
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- Citations: 2
Herrando M, Chordá R, Gómez A, et al., 2023, The cost overrun of depopulation to improve energy efficiency in buildings: A case study in the Mediterranean Region, Sustainable Energy Technologies and Assessments, Vol: 55, ISSN: 2213-1388
The implementation of energy efficiency measures in public buildings is a complex process that hinges on multiple factors. A factor relevant for some European regions is their ongoing depopulation. In these regions, building energy retrofitting presents additional challenges to those in urban areas, such as over-dimensioned public buildings and low occupancy levels. This work analyses these challenges in the province of Teruel (Spain), one of the regions with the highest depopulation levels in Spain. To this end, a methodology has been developed to assess the effect of depopulation on the cost of upgrading public buildings to improve their energy efficiency. The results show that the investment required per inhabitant for building retrofitting is approximately four times as high in depopulated areas as in urban areas. Furthermore, the low occupancy levels of public buildings can triple the payback time of some energy efficiency measures. To overcome these barriers, in addition to specific policies for depopulated areas, energy planning is essential. An adequate action plan, combining the implementation of energy efficiency measures and the integration of renewable energies in buildings, is the most effective tool to improve the sustainability of public buildings circumventing the barriers created by depopulation.
Herrando M, Ramos A, 2022, Photovoltaic-Thermal (PV-T) Systems for Combined Cooling, Heating and Power in Buildings: A Review, ENERGIES, Vol: 15
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- Citations: 14
Herrando M, Elduque D, Javierre C, et al., 2022, Life Cycle Assessment of solar energy systems for the provision of heating, cooling and electricity in buildings: A comparative analysis, ENERGY CONVERSION AND MANAGEMENT, Vol: 257, ISSN: 0196-8904
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- Citations: 18
Herrando M, Gomez A, Fueyo N, 2022, Supporting Local Authorities to Plan Energy Efficiency in Public Buildings: From Local Needs to Regional Planning, ENERGIES, Vol: 15
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- Citations: 9
Herrando M, Simon R, Guedea I, et al., 2021, The challenges of solar hybrid PVT systems in the food processing industry, APPLIED THERMAL ENGINEERING, Vol: 184, ISSN: 1359-4311
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- Citations: 22
Coca-Ortegón A, Herrando M, Simón-Allué R, et al., 2021, Experimental Study of a Heating and Cooling Pilot Installation Driven by a Hybrid PV-Thermal Solar Field, Pages: 640-650
This paper studies the energy performance of a pilot plant of a trigeneration system, that provides heating, cooling and electricity in an office area of an industrial building, using an air-to-water heat pump, driven mainly by the electricity produced by a liquid-based photovoltaic-thermal (PVT) solar field. The heat pump has a nominal capacity of 16 kW in heating, and 10.5 kW in cooling; and the PVT solar field has a total gross area of 13.6 m2, with a nominal electrical power of 2.56 kWp. The pilot installation was monitored and analyzed for eight weeks during the winter and summer seasons. The results show that under real operation conditions, the PVT solar field has average thermal efficiency between 19.3 and 22.4% during the winter weeks, and between 25.4 and 28.3% during the summer weeks. The electrical efficiency varies between 15.7 and 16.2%, with no relevant difference between the winter and summer weeks. Thanks to the PVT electrical generation and the heat pump performance,e, the system achieves high electrical solar cover factors during both: summer and winter weeks..
Salvia M, Simoes SG, Herrando M, et al., 2021, Improving policy making and strategic planning competencies of public authorities in the energy management of municipal public buildings: The PrioritEE toolbox and its application in five mediterranean areas, RENEWABLE & SUSTAINABLE ENERGY REVIEWS, Vol: 135, ISSN: 1364-0321
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- Citations: 14
Wang K, Pantaleo AM, Herrando M, et al., 2020, Spectral-splitting hybrid PV-thermal (PVT) systems for combined heat and power provision to dairy farms, Renewable Energy, Vol: 159, Pages: 1047-1065, ISSN: 0960-1481
Dairy farming is one of the most energy- and emission-intensive industrial sectors, and offers noteworthy opportunities for displacing conventional fossil-fuel consumption both in terms of cost saving and decarbonisation. In this paper, a solar-combined heat and power (S–CHP) system is proposed for dairy-farm applications based on spectral-splitting parabolic-trough hybrid photovoltaic-thermal (PVT) collectors, which is capable of providing simultaneous electricity, steam and hot water for processing milk products. A transient numerical model is developed and validated against experimental data to predict the dynamic thermal and electrical characteristics and to assess the thermoeconomic performance of the S–CHP system. A dairy farm in Bari (Italy), with annual thermal and electrical demands of 6000 MWh and 3500 MWh respectively, is considered as a case study for assessing the energetic and economic potential of the proposed S–CHP system. Hourly simulations are performed over a year using real-time local weather and measured demand-data inputs. The results show that the optical characteristic of the spectrum splitter has a significant influence on the system’s thermoeconomic performance. This is therefore optimised to reflect the solar region between 550 nm and 1000 nm to PV cells for electricity generation and (low-temperature) hot-water production, while directing the rest to solar receivers for (higher-temperature) steam generation. Based on a 10000-m2 installed area, it is found that 52% of the demand for steam generation and 40% of the hot water demand can be satisfied by the PVT S–CHP system, along with a net electrical output amounting to 14% of the farm’s demand. Economic analyses show that the proposed system is economically viable if the investment cost of the spectrum splitter is lower than 75% of the cost of the parabolic trough concentrator (i.e., <1950 €/m2 spectrum splitter) in this application. The influenc
Herrando M, Coca-Ortegon A, Guedea I, et al., 2020, Solar Assisted Heat Pump Systems Based on Hybrid PVT Collectors for the Provision of Hot Water, Cooling and Electricity in Buildings, 13th International Conference on Solar Energy for Buildings and Industry (ISES EuroSun), Publisher: INTL SOLAR ENERGY SOC, Pages: 540-550
Herrando M, Pantaleo AM, Wang K, et al., 2019, Solar combined cooling, heating and power systems based on hybrid PVT, PV or solar-thermal collectors for building applications, Renewable Energy, Vol: 143, Pages: 637-647, ISSN: 0960-1481
A modelling methodology is developed and used to investigate the technoeconomic performance of solar combined cooling, heating and power (S-CCHP) systems based on hybrid PVT collectors. The building energy demands are inputs to a transient system model, which couples PVT solar-collectors via thermal-store to commercial absorption chillers. The real energy demands of the University Campus of Bari, investment costs, relevant electricity and gas prices are used to estimate payback-times. The results are compared to: evacuated tube collectors (ETCs) for heating and cooling provision; and a PV-system for electricity provision. A 1.68-MWp S-CCHP system can cover 20.9%, 55.1% and 16.3% of the space-heating, cooling and electrical demands of the Campus, respectively, with roof-space availability being a major limiting factor. The payback-time is 16.7 years, 2.7-times higher than that of a PV-system. The lack of electricity generation by the ETC-based system limits its profitability, and leads to 2.3-times longer payback-time. The environmental benefits arising from the system’s operation are evaluated. The S-CCHP system can displace 911 tonsCO2/year (16% and 1.4× times more than the PV-system and the ETC-based system, respectively). The influence of utility prices on the systems’ economics is analysed. It is found that the sensitivity to these prices is significant.
Wang K, Herrando M, Pantaleo AM, et al., 2019, Technoeconomic assessments of hybrid photovoltaic-thermal vs. conventional solar-energy systems: Case studies in heat and power provision to sports centres, Applied Energy, Vol: 254, Pages: 1-16, ISSN: 0306-2619
This paper presents a comprehensive analysis of the energetic, economic and environmental potentials of hybrid photovoltaic-thermal (PVT) and conventional solar energy systems for combined heat and power provision. A solar combined heat and power (S-CHP) system based on PVT collectors, a solar-power system based on PV panels, a solar-thermal system based on evacuated tube collectors (ETCs), and a S-CHP system based on a combination of side-by-side PV panels and ETCs (PV-ETC) are assessed and compared. A conventional CHP system based on a natural-gas-fired internal combustion engine (ICE) prime mover is also analysed as a competing fossil-fuel based solution. Annual simulations are conducted for the provision of electricity, along with space heating, swimming pool heating and hot water to the University Sports Centre of Bari, Italy. The results show that, based on a total installation area of 4000 m2 in all cases, the PVT S-CHP system outperforms the other systems in terms of total energy output, with annual electrical and thermal energy yields reaching 82.3% and 51.3% of the centre’s demands, respectively. The PV system is the most profitable solar solution, with the shortest payback time (9.4 years) and lowest levelised cost of energy (0.089 €/kWh). Conversely, the ETC solar-thermal system is not economically viable for the sports centre application, and increasing the ETC area share in the combined PV-ETC S-CHP system is unfavourable due to the low natural gas price. Although the PVT S-CHP system has the highest investment cost, the high annual revenue from the avoided energy bills elevates its economic performance to a level between those of the conventional PV and ETC-based S-CHP systems, with a payback time of 13.7 years and a levelised cost of energy of 0.109 €/kWh. However, at 445 tCO2/year, the CO2 emission reduction potential of the PVT S-CHP system is considerably higher (by 40–75%) than those of the all other solar systems (254&ndash
Wang K, Pantaleo AM, Herrando M, et al., 2019, Thermoeconomic assessment of a spectral-splitting hybrid PVT system in dairy farms for combined heat and power, The 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 2019)
Herrando Zapater M, Ramos Cabal A, Zabalza I, et al., 2019, A comprehensive assessment of alternative absorber-exchanger designs for hybrid PVT-water collectors, Applied Energy, Vol: 235, Pages: 1583-1602, ISSN: 0306-2619
In this paper, 26 alternative absorber-exchanger designs for hybrid PV-Thermal (PVT) solar collectors are proposed and compared against a reference-case, commercial sheet-and-tube PVT collector. The collectors involve different geometric design features based on the conventional sheet-and-tube configuration, and also on a newer flat-box structure constructed from alternative polymeric materials with the aim of maintaining or even improving heat transfer and overall (thermal and electrical) performance while achieving reductions in the overall weight and cost of the collectors. The main contributions of this research include: (i) the development and validation of a detailed 3-D computational finite-element model of the proposed PVT collector designs involving multi-physics processes (heat transfer, fluid dynamics and solid mechanics); (ii) results from comparative techno-economic analyses of the proposed PVT designs; and, (iii) further insights from thermal stress and structural deformation analyses of the proposed collectors, which are crucial for ensuring long lifetimes and especially important in the case of polymeric collectors. The results show that, in general, the flat-box designs (characterised by a thin absorber plate) are not sensitive to the flow-channel size or construction material, at least within the range of investigation. A PVT collector featuring a polycarbonate (PC) flat-box design with 3 × 2 mm rectangular channels appears to be a particularly promising alternative to commercial PVT collectors, achieving a slightly improved thermal performance compared to the reference case (with a 4% higher optical efficiency and 15% lower linear heat-loss coefficient), while also lowering the weight (by around 9%) and investment cost (by about 21%) of the collector. The structural analysis shows that the maximum von Mises stress experienced in the absorber-exchanger of the PC flat-box collector is considerably lower than that in the copper sheet-and-tube c
Wang K, Herrando M, Pantaleo AM, et al., 2019, Thermoeconomic assessment of a PV/T combined heating and power system for University Sport Centre of Bari, 10th International Conference on Applied Energy (ICAE2018), Publisher: Elsevier, Pages: 1229-1234, ISSN: 1876-6102
This paper presents a thermoeconomic analysis of a solar combined heating and power (S-CHP) system based on hybridphotovoltaic-thermal (PV/T) collectors for the University Sport Centre (USC) of Bari, Italy. Hourly demand data for space heating,swimming pool heating, hot water and electricity provision as well as the local weather data are used as inputs to a transient modeldeveloped in TRNSYS. Economic performance is evaluated by considering the investment costs and the cost savings due to thereduced electricity and natural gas consumptions. The results show that 38.2% of the electricity demand can be satisfied by thePV/T S-CHP system with an installation area of 4,000 m2. The coverage increases to 81.3% if the excess electricity is fed to thegrid. In addition, the system can cover 23.7% of the space heating demand and 53.8% of the demands for the swimming pool andhot water heating. A comparison with an equivalent gas-fired internal combustion engine (ICE) CHP system shows that the PV/Tsystem has a higher payback time, i.e., 11.6 years vs. 3 years, but outperforms the ICE solution in terms of CO2 emission reduction,i.e., 435 tons CO2/year vs. 164 tons CO2/year. This work suggests that the proposed PV/T S-CHP system has a good potential ofdecarbonisation, while the economic competitiveness should be further enhanced to boost its deployment.
Gouveia JP, Simoes SG, Cavar M, et al., 2019, A DECISION SUPPORT TOOL TO RANK ENERGY EFFICIENCY OPTIONS IN SERVICES BUILDINGS, 4th International Conference on Energy and Environment - Bringing together Engineering and Economics (ICEE), Publisher: UNIV MINHO, Pages: 220-225, ISSN: 2183-3982
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- Citations: 2
Herrando M, Ramos A, Freeman J, et al., 2018, Technoeconomic modelling and optimisation of solar combined heat and power systems based on flat-box PVT collectors for domestic applications, Energy Conversion and Management, Vol: 175, Pages: 67-85, ISSN: 0196-8904
We investigate solar combined heat and power (S-CHP) systems based on hybrid photovoltaic-thermal (PVT) collectors for the simultaneous provision of domestic hot water (DHW), space heating (SH) and power to single- family homes. The systems include PVT collectors with a polycarbonate flat-box structure design, a water storage tank, an auxiliary heater and a battery storage subsystem. A methodology is developed for modelling the en- ergetic and economic performance of such PVT-based S-CHP systems, which is used to optimally size and operate systems for covering the energy demands of single-family reference households at three selected locations: Athens (Greece), London (UK) and Zaragoza (Spain). The results show that optimised systems are capable of covering ∼65% of the annual household electricity demands in Athens, London and Zaragoza when employing 14.0, 17.0 and 12.4 m2 collector array areas respectively, while also covering a significant fraction of the thermal energy demands in Athens (∼60%) and Zaragoza (∼45%); even in London, almost 30% of the reference household’s thermal demand is covered by such a system. A corresponding economic analysis reveals that, despite the suitability of Athens’ weather conditions for implementing such solar-energy systems, the payback time (PBT) of the optimised S-CHP system in Athens is 15.6 years in contrast to the 11.6 years predicted for Zaragoza, due to the lower electricity prices in Greece. On the other hand, the high carbon emission factor of the electricity grid in Greece makes these systems particularly promising at this location. Specifically, the in- vestigated systems have the potential to displace 3.87, 1.65 and 1.54 tons of CO2 per year in Athens, London and Zaragoza, when substituting the conventional means for household energy provision (i.e. grid electricity and gas- fired boilers). Furthermore, it is demonstrated that the optimised systems outperform benchmark equivalent systems comprisin
Herrando M, Ramos A, Zabalza I, 2018, Cost competitiveness of a novel PVT-based solar combined heating and power system: Influence of economic parameters and financial incentives, ENERGY CONVERSION AND MANAGEMENT, Vol: 166, Pages: 758-770, ISSN: 0196-8904
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- Citations: 38
Herrando M, Ramos A, Zabalza I, et al., 2017, Structural characterization and energy performance of novel hybrid PVT solar-panels through 3-D FEM and CFD simulations, ECOS 2017
Hybrid Photovoltaic-Thermal (PVT) panels generate both power and heat from the same area with overall efficiencies up to 70%. This work assesses the performance of novel hybrid PVT solar panels considering alternative geometries and materials that maximize heat transfer while allowing weight and cost reductions. A three-dimensional (3-D) model previously developed and validated using 3-D Finite-Element and Computational Fluid-Dynamics (FEM and CFD) software is used for this purpose. The most promising configurations and materials for the absorber-exchanger unit of the proposed PVT panel are studied to analyse their energy performance and behaviour in terms of a thermal-stress assessment. Apart from an assessment of the steady-state performance, for the type of solar PVT panels considered, especially those made of polymeric materials, it is important to evaluate the thermal expansion that the collector suffers, so as to verify whether the associated thermal stresses and strains are within the limits that guarantee a proper performance during its lifetime. The most promising PVT panel is then integrated within a Solar Combined Heat and Power (S-CHP) system for power and heating provision to a single-family house located in Zaragoza (Spain), in order to assess its daily energy performance through transient simulations on half-hourly basis. The results show that these novel polymeric PVT panel configurations are a promising alternative to commercial PVT panel designs, achieving an improved thermal performance compared to a reference case (4% higher optical efficiency and 15% lower heat loss coefficient), while suffering lower strains in most of the PVT layers. Furthermore, the novel polycarbonate 3×2 mm flat-box configuration has the potential to cover, on average, around 50% of the total space heating and Domestic Hot Water (DHW) demand and around 87% of the total electricity demand (including lighting, cooling and home appliances).
Herrando M, Guarracino I, del Amo A, et al., 2017, Energy Characterization and Optimization of New Heat Recovery Configurations in Hybrid PVT Systems, 11th ISES EuroSun Conference, Publisher: INTL SOLAR ENERGY SOC, Pages: 1228-1239
Herrando M, Ramos A, Zabalza I, et al., 2017, Energy performance of a solar trigeneration system based on a novel hybrid PVT panel for residential applications, Pages: 1090-1101
The overall aim of this work is to assess the performance of high-efficiency solar trigeneration systems based on a novel hybrid photovoltaic-thermal (PVT) collector for the provision of domestic hot water (DHW), space heating (SH), cooling and electricity to residential single-family households. To this end, a TRNSYS model is developed featuring a novel hybrid PVT panel based on a new absorber-exchanger configuration coupled via a thermal store to two alternative small-scale solar heating and cooling configurations, one based on an electrically-driven vapour-compression heat pump (PVT+HP) and one on a thermally-driven absorption refrigeration unit (PVT+AR). The energy demands of a single-family house located in three different climates, namely Seville (Spain), Rome (Italy) and Paris (France), are estimated using EnergyPlus. Hourly transient simulations of the complete systems considering real weather data and reasonable areas for collector installation (< 30 m2) are conducted over a year. The household energy demands covered by the two systems indicate that the PVT+HP configuration is the most promising for the locations of Rome and Paris, covering more than 74% the DHW demand, 100% of the space heating and cooling demands, as well as an important share of the electricity demand. Meanwhile, for Seville, the PVT+AR configuration appears as a promising alternative, covering more than 80% of the DHW, around 70% of the cooling and electricity, and 54% of the space heating demands.
Janez Moran A, Profaizer P, Herrando Zapater M, et al., 2016, Information and Communications Technologies (ICTs) for energy efficiency in buildings: Review and analysis of results from EU pilot projects, ENERGY AND BUILDINGS, Vol: 127, Pages: 128-137, ISSN: 0378-7788
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- Citations: 39
Herrando M, Cambra D, Navarro M, et al., 2016, Energy Performance Certification of Faculty Buildings in Spain: The gap between estimated and real energy consumption, Energy Conversion and Management, Vol: 125, Pages: 141-153, ISSN: 0196-8904
Duarte AP, Goncalves A, Joyce A, et al., 2016, VOCATIONAL TRAINING ON SUSTAINABLE BUILDINGS MAINTENANCE AND REFURBISHMENT - PRELIMINARY RESULTS OF FORMAR PROJECT, 8th International Conference on Education and New Learning Technologies (EDULEARN), Publisher: IATED-INT ASSOC TECHNOLOGY EDUCATION & DEVELOPMENT, Pages: 31-40, ISSN: 2340-1117
Markides CN, Herrando M, 2015, Hybrid PV and solar-thermal systems for domestic heat and power provision in the UK: Techno-economic considerations, Applied Energy, Vol: 161, Pages: 512-532, ISSN: 0306-2619
A techno-economic analysis is undertaken to assess hybrid PV/solar-thermal (PVT) systems for distributedelectricity and hot-water provision in a typical house in London, UK. In earlier work (Herrando et al., 2014), asystem model based on a PVT collector with water as the cooling medium (PVT/w) was used to estimateaverage year-long system performance. The results showed that for low solar irradiance levels and lowambient temperatures, such as those associated with the UK climate, a higher coverage of total householdenergy demands and higher CO2 emission savings can be achieved by the complete coverage of the solar collectorwith PV and a relatively low collector cooling flow-rate. Such a PVT/w system demonstrated an annualelectricity generation of 2.3 MW h, or a 51% coverage of the household’s electrical demand (compared to anequivalent PV-only value of 49%), plus a significant annual water heating potential of to 1.0 MW h, or a 36%coverage of the hot-water demand. In addition, this system allowed for a reduction in CO2 emissionsamounting to 16.0 tonnes over a life-time of 20 years due to the reduction in electrical power drawn fromthe grid and gas taken from the mains for water heating, and a 14-tonne corresponding displacement of primaryfossil-fuel consumption. Both the emissions and fossil-fuel consumption reductions are significantlylarger (by 36% and 18%, respectively) than those achieved by an equivalent PV-only system with the samepeak rating/installed capacity. The present paper proceeds further, by considering the economic aspects ofPVT technology, based on which invaluable policy-related conclusions can be drawn concerning the incentivesthat would need to be in place to accelerate the widespread uptake of such systems. It is found that,with an electricity-only Feed-In Tariff (FIT) support rate at 43.3 p/kW h over 20 years, the system cost estimatesof optimised PVT/w systems have an 11.2-year discounted payback period (PV-only: 6.8 years). Therole and i
Herrando M, Cambra D, Duarte AP, et al., 2015, DEVELOPMENT OF NEW VOCATIONAL TRAINING MODULES ON SUSTAINABLE BUILDINGS MAINTENANCE AND REFURBISHMENT, 8th International Conference of Education, Research and Innovation (ICERI), Publisher: IATED-INT ASSOC TECHNOLOGY EDUCATION A& DEVELOPMENT, Pages: 6212-6222, ISSN: 2340-1095
Herrando M, Markides CN, Hellgardt K, 2014, A UK-based assessment of hybrid PV and solar-thermal systems for domestic heating and power: System performance, Applied Energy, Vol: 122, Pages: 288-309, ISSN: 1872-9118
The goal of this paper is to assess the suitability of hybrid PVT systems for the provision of electricity andhot water (space heating is not considered) in the UK domestic sector, with particular focus on a typicalterraced house in London. A model is developed to estimate the performance of such a system. The modelallows various design parameters of the PVT unit to be varied, so that their influence in the overall systemperformance can be studied. Two key parameters, specifically the covering factor of the solar collectorwith PV and the collector flow-rate, are considered. The emissions of the PVT system are compared withthose incurred by a household that utilises a conventional energy provision arrangement. The resultsshow that for the case of the UK (low solar irradiance and low ambient temperatures) a complete coverageof the solar collector with PV together with a low collector flow-rate are beneficial in allowing thesystem to achieve a high coverage of the total annual energy (heat and power) demand, while maximisingthe CO2 emissions savings. It is found that with a completely covered collector and a flow-rate of 20 L/h,51% of the total electricity demand and 36% of the total hot water demand over a year can be coveredby a hybrid PVT system. The electricity demand coverage value is slightly higher than the PV-only systemequivalent (49%). In addition, our emissions assessment indicates that a PVT system can save up to16.0 tonnes of CO2 over a lifetime of 20 years, which is significantly (36%) higher than the 11.8 tonnesof CO2 saved with a PV-only system. All investigated PVT configurations outperformed the PV-only systemin terms of emissions. Therefore, it is concluded that hybrid PVT systems offer a notably improvedproposition over PV-only systems.
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