Building Integrated Photovoltaic Thermal Research Articles

Multi-objective optimization and evaluation of the building-integrated photovoltaic/thermal-energy pile ground source heat pump system

Building integrated photovoltaic thermal (BIPV/T)-energy pile ground source heat pump (GSHP) system effectively maintains the soil thermal balance and improves the photovoltaic efficiency by recovering the waste solar heat from the BIPV/T collector to charge the ground. However, due to the strict carbon emission restriction and economic consideration for system application, multi-objective optimization should be implemented for the system design to further enhance its overall performance. Therefore, a complete optimization framework is proposed in this paper, which is based on the NSGA-II algorithm and functions by coupling TRNSYS and jEPlus+EA. Using the proposed optimization frame, a comprehensive optimization is conducted for the system, which optimizes five main design variables and adopts the total power consumption (TPC), life cycle climate performance (LCCP), and life cycle cost (LCC) to reflect the system's energetic, environmental, and economic performances. Seven optimization cases are included in the optimization project to identify design schemes that meet all possible proposed performance requirements for the system application. The optimized results show that the system optimization improves its performance greatly compared to the design condition, with a range of 38.03% ∼ 50.05% for the TPC, 24.52% ∼ 25.86% for LCCP, and 56.74% ∼ 61.66% for LCC. The energetic, environmental and economic performances of the system can be maximized by minimizing the TPC to 357.29 MWh in Case 1, LCCP to 596.15 tCO2 in Case 2, and LCC to 17.03 × 104 CNY in Case 3. By breaking down the objective functions, it is found that the heat pump unit holds paramount importance in all aspects of system performance, and the BIPV/T collector proves advantageous in enhancing the system's long-term performance due to its massive electricity generation. Accordingly, one important finding is that it is advisable to incorporate as many BIPV/T collectors as feasible while maintaining soil heat balance. The optimal energy pile number varies among the seven optimization cases, resulting in different heating capacities for the heat pump unit. Research outcomes in this work offer references for designing the energy-pile GSHP system to enhance the penetration of renewable energy into buildings.

Experimental investigation of BIPV/T application in winter season under Şanlıurfa's meteorological conditions

AbstractConsidering that nearly 39% of the total CO2 emission released into the atmosphere today are thought to be due to the energy consumed by buildings, the importance of taking measures through buildings to combat global warming is evident. Therefore, the concept of nearly zero‐energy buildings (NZEB) is come to the forefront. Building integrated photovoltaic thermal (BIPV/T) systems are used to enable buildings to generate their own energy. However, buildings have limited facade and roof areas required for BIPV/T systems. Therefore, in this study, various configurations of bifacial (double‐sided) and monofacial (single‐sided) panels were compared to investigate ways to enhance the efficiency of BIPV/T systems. Different air flow velocities and varying air gap distances were tested for both panel types. By placing a reflective surface on the wall behind the bifacial panel, the electrical efficiency of the bifacial panel was increased and proven through PVsyst analysis. Both panels provided maximum heat efficiency at the shortest air gap distance under high air flow conditions. In addition, it was shown in both the experimental setup and Comsol CFD analysis that it provides significant benefit in the thermal energy load of the building when heating the interior environment in winter. In terms of electrical power production surplus, the bifacial panel outperformed the monofacial panel in all configurations, with a minimum advantage of 8.33% and a maximum of 12.73%. Additionally, the maximum electrical efficiency was obtained from the bifacial panel in configurations with the longest air gap distance. Using the bifacial panel in the BIPV/T system with the shortest air gap distance during the heating season and the longest air gap distance during other seasons can provide the highest efficiency for the building throughout the year.

Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile

Among renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system was developed in the ANSYS Fluent software for a wide range of input variables. The original approach based on the SST k-ω turbulence model, Discrete Ordinates radiation model, and the use of Solar Load module were proposed. Such a numerical model allows representation of semi-transparent layers and variable solar irradiance, which is a unique realization of real system modelling. Numerous analyses conducted indicate a higher heat recovery potential for an airflow duct with a height of 25 mm for all configurations analysed. The highest value of recovered heat flux was approximately 330 W/m2 under conditions of a volumetric air flow rate of 7.5 m3/h and solar irradiance equal to 900 W/m2. Good agreement of the results of the multivariant CFD simulations with new experimental ones was confirmed. Insight into the flow phenomena behind the achieved thermal results supplemented the knowledge. The highest electrical efficiency obtained experimentally was 5.76 % for a channel with a height of 50 mm, volumetric flow rate equal to 7.5 m3/h and solar irradiance equal to 600 W/m2. The presented methodology and the results obtained can be useful in research devoted to optimising BIPV/T air-based cooling systems, which will then be tested in-situ. Moreover, new experimental data collection can be used for the verification of numerical models.

Camera-based plant growth monitoring for automated plant cultivation with controlled environment agriculture

Building integrated photovoltaic thermal (BIPVT) greenhouse technology exhibits great potential to enhance crop yielding, energy harvesting, and water management for highly efficient farming and enables controlled environment agriculture (CEA) for automated plant cultivation. The proposed smart greenhouse system uses BIPVT, geothermal, image-based sensing, and control technologies for high energy efficiency and high-fidelity plant growth control. A camera-based, computer-controlled system was demonstrated to successfully monitor single and multiple food plants' growth. The growth rate over the life-cycle of the plant was automatically recorded by cameras without human interference. A novel algorithm was developed to extract the plants from the background of the image and then to measure the length from the ground to the top of the longest plant with different shapes or profiles. The growth rate was automatically generated as fundamental data for farming management and control. Because the plant growth is slow and the errors caused by image noise can be comparable with the actual growth when the interval between images is not large enough, the noise of a camera is evaluated by comparing multiple images under the same exposure condition, which is used to provide the error range of the measurements. The plant growth monitoring system will be integrated into an ongoing greenhouse project for smart greenhouse operation.

Energy and economic analysis of building integrated photovoltaic thermal system: Seasonal dynamic modeling assisted with machine learning-aided method and multi-objective genetic optimization

Building integrated photovoltaic thermal (BIPV/T) systems offer a highly effective means of generating clean energy for both electricity and heating purposes in residential buildings. Hence, this article introduces a new BIPV/T system to optimally minimize the energy consumption of a household residential building. The meticulous design of the proposed BIPV/T system is accomplished through MATLAB/Simulink® dynamic modeling. Performance analysis for the BIPV/T system is performed under different seasonal conditions with in-depth techno-economic analyses to estimate the expected enhancement in the thermal, electrical, and economic performance of the system. Moreover, a sensitivity analysis is conducted to explore the impact of various factors on the energetic and economic performances of the proposed BIPV/T system. More so, the two-layer feed-forward back-propagation artificial neural network modeling is developed to accurately predict the hourly solar radiation and ambient temperature for the BIPV/T. Additionally, a multi-objective optimization using the NSGA-II method is also conducted for the minimization of the total BIPV/T plant area and maximization of the total efficiency and net thermal power of the system as well as to estimate the optimized operating conditions for input variables across different seasons within the provided ranges. The sensitivity analysis revealed that higher solar flux levels lead to increased electric output power of the BIPV/T plant, but total efficiency decreases due to higher thermal losses. Moreover, the proposed NSGA-II shows a feasible method to attain a maximum net thermal power and optimal total efficiency of 5320 W and 63% with a minimal total plant area of 32.89 m2 that attained a very low deviation index from the ideal solution. The levelised cost of electricity is obtained as 0.10 $/kWh under the optimal conditions. Thus, these findings offer valuable insights into the potential of BIPV/T systems as a sustainable and efficient energy solution for residential applications.

A 4E Comparative Study between BIPV and BIPVT Systems in Order to Achieve Zero-Energy Building in Cold Climate

The growing demand for energy has led to the popularity of building integrated photovoltaic (BIPV) systems. However, photovoltaic (PV) system efficiency decreases as the temperature increases. To address this issue, a study was conducted on a BIPV thermal (BIPVT) system, which can generate both thermal and electrical energy, to enhance its efficiency. In this study, for the cold weather in Tabriz city in Iran, BIPV and BIPVT systems are compared with each other in terms of energy, economy, exergy, and environment (4E) and the goal is to fully supply the thermal and electrical load of the desired building. The studied criteria are electrical power and heat recovery, payback time (PBT), exergy efficiency, and saved carbon dioxide (SCD) from the energy, economic, exergy, and environmental point of view, respectively. Finally, it is concluded that in cold weather, the BIPVT system can achieve a 7.15% improvement in produced power compared to the BIPV system and 52.2% of the building’s heating needs are provided. It also causes the exergy efficiency to improve by an average of 1.69% and saves 34.98 ton of carbon dioxide. The PBT of this study is calculated as 5.77 years for the BIPV system and 4.78 years for the BIPVT system.

Numerical examination of exergy performance of a hybrid solar system equipped with a sheet-and-sinusoidal tube collector: Developing a predictive function using artificial neural network

Integrating cooling systems with photovoltaic-thermal (PVT) collectors has the potential to mitigate the exergy consumption in the building sector due to their capability for simultaneous power and thermal energy generation. The simultaneous utilization of nanofluid and geometry modification resulted in a synergetic enhancement in the performance of PVTs and thereby reducing their sizes and costs. In addition, there is still a lack of high accurate predictive model for the estimation of the performance of PVTs at a given Re number and nanofluid concentration ratio to be used in engineering design for the further product commercialization. To this end, the current numerical study investigates the exergy electricity, thermal, and overall exergies of a building-integrated photovoltaic thermal (BIPVT) solar collector with Al2O3/water coolant. The increase in nanoparticle concentration (ω) from 0 % to 1 % increased the useful thermal exergy and overall exergy efficiency (Exu,t/ Υov) by 0.3999 %/0.0497 %, 1.3959 %/0.2598 %, and 0.7489 %/0.1771 % at Re numbers of 500, 1000, and 1500, respectively, while Exu,t/ Υov exhibited a reducing trend at Re = 2000; 0.3928 %/0.1056 % decrease. In addition, the increase in ω from 0 % to 1 % caused the useful electricity and electrical exergy (Exu,e/ Υe) to be diminished by 0.0060 %/0.0025 % at Res 500 and 1000, and to be escalated by 0.0113 %/0.0055 % at Res of 1500 and 2000. Meanwhile, the Re augmentation, from 500 to 2000, improved the Exu,t, Exe, Υe, and Υov by 60 %, 1.26 %, 1.26 %, and 17.50 %, respectively, at different ω s. In addition, two functions were developed and proposed by applying a group method of data handling-type neural network (GMDH-ANN) to forecast the value of Υov based on two input values (Re and ω). The results showed high accuracy of the proposed model with MSE, EMSE, and R2 of 0.0138, 0.1143, and 0.99785, respectively.

Experimental study of a heat recovery ventilator preheated by a Building Integrated Photovoltaic system in a cold climate

The use of heat recovery ventilators (HRVs) in cold climate housing is becoming increasingly common, to provide outside air to the occupied space while recovering heat from the exhausted air. However, frosting of the heat exchanger core impedes HRV operation in cold climate conditions. Strategies for defrosting the core include recirculating the exhaust airstream while stopping the supply of the outside air during the defrost cycle. Preheating the air using heating coils is also used, but its application is limited by the increased energy use of the preheater. This study aims to investigate the impact of a building integrated photovoltaic/thermal (BIPV/T) system on the HRV thermal performance by using it to preheat the outside air. In this experimental study, measurements of a heat recovery ventilator preheated by the BIPV/T system are carried out in a test cell of the Future Buildings Laboratory (FBL) at Concordia University in Montreal, Canada. The results are compared to a HRV without BIPV/T preheating. The relative humidity, temperature and airflow rate of the fresh air and exhaust airstreams are monitored at the inlet and outlet of the HRV. The experiments are conducted during two weeks from January 26th, 2023 to February 08th, 2023. The change of the sensible heat recovery effectiveness ∈ sens of the HRV, outside air outlet temperature T 2 from the HRV and outside air flow rate, ṁ1 and exhaust air flow rate ṁ4 are determined. The primary experimental results indicate that preheating the outside air by the BIPV/T system before entering the HRV can help to increase the outside air outlet temperature T 2 by up to 2.7°C at an outdoor temperature of -25 °C, and the sensible heat recovery effectiveness ∈ sens , outside air flow rate, ṁ1 (23L/s) and exhaust air flow rate ṁ4 (43L/s) of the HRV are kept constant at the same level with preheating by BIPV/T on the HRV at -5 °C to -25 °C of outdoor temperature.

Study on impact of photovoltaic power tracking modes on photovoltaic-photothermal performance of PV-PCM-Trombe wall system

Due to the lack of research on the impact of photovoltaic (PV) power tracking methods on the performance of Building-Integrated Photovoltaic-Thermal (BIPV/T) systems, this study comparatively analyzes the photovoltaic-photothermal performance of the PV-PCM-Trombe Wall system operating in Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT) modes during winter passive heating conditions. Additionally, the study investigates the influence of these modes on the thermal characteristics of buildings. The results indicate that the MPPT strategy achieved a PV efficiency of 15.50 %, while the PWM strategy resulted in a significant reduction to 12.72 % (a decrease of 2.78 % compared to MPPT). Importantly, both strategies effectively utilized solar energy for passive space heating without noticeable differences in photothermal performance. Furthermore, the study observed that the upper part of the PCM plate reached higher peak temperatures earlier in the vertical dimension. Experiment A exhibited peak temperatures ranging from 33.57 °C to 34.76 °C, while Experiment B had a wider range of 27.99 °C to 36.10 °C. Minimal temperature variations were observed across the PCM plate in the thickness direction, measuring only 0.60 °C in Experiment A and 0.70 °C in Experiment B. These research findings provide valuable insights into the roles and impacts of different PV power tracking strategies in PV-PCM-Trombe wall systems.

Experimental performance analysis of photovoltaic systems applied to an positive energy community based on building renovation

Global carbon neutrality can be achieved by reducing greenhouse gas emissions in the building sector using various renewable energy systems, such as photovoltaic (PV) systems, at the community level. In this study, various PV systems were applied to a community consisting of two residential and two nonresidential buildings, and a comparative analysis was conducted to achieve a net yearly positive energy balance at the community level. The PV systems included building-attached PV (BAPV), building-integrated PV (BIPV), and BIPV–thermal (BIPVT) systems. An analysis of the empirical data over a year revealed that the annual net energy balance of the proposed community was 139%, the self-sufficiency of building energy consumption was 33.2%, and the self-consumption of solar power generation was 76.7%. Based on these empirical data, the initial investment cost savings of the PV system and payback period were analyzed through carbon credit trading. The results showed that the payback period ranged from 9 to 17 years.

The effects of using twisted tape, ferrofluid, and external magnetic field on hydrothermal performance and entropy generation of the building integrated photovoltaic thermal collectors

The numerical analysis of the present study was performed to evaluate the usefulness of twisted tape insert inside a building integrated photovoltaic thermal (BIPVT) system in the presence of an external Magnetic Field (MF) aimed to reducing the system size. The results demonstrated that the MF reduces PV plate temperature (TPV) by 1.13%-0.89%, 2.21%-1.96%, 1.61%-1.36%, and 1.38%-1.04% in the plain tube and twisted tubes with pitch distances (Pd) of 50 mm, 75 mm, and 150 mm, respectively, at Res of 400–600. In addition, the pressure drop (ΔP) escalates by 30.87%-27.36% in the presence of the MF for the plain tube. However, in the twisted tubes, ΔP under the MF effect has an increasing or decreasing trend. ΔP at Pds of 50 mm, 75 mm, and 150 mm, is 87% (or 83%), 82% (or 78%), and 76% (or 71%) higher than that in the plain tube, respectively, in the absence (or presence) of the MF effect. In addition, the increase in Re from 400 to 600 improves the electrical efficiency by 1.89–1.47% for the plain tube and 2.24–1.41% using three turbulators in the tube, respectively, for the without-with scenarios of MF effect. In addition, the increase in Re from 400 to 600 leads to escalating the frictional entropy generation rate by 52–62%.

Performance prediction of a curved-type solar balcony combined with the flexible PV/T system during the non-heating season

Curved surfaces are vital elements for well-designed buildings, while related system design is scarce in the building-integrated photovoltaic/thermal (BIPV/T) field. This study proposes a curved-type solar balcony combined with the flexible PV/T system, aiming to realize the curved PV/T façade application, which could generate electricity and provide hot water. The theoretical model to describe the electrical and thermal behavior of the curved balcony system is put forward and verified. Furthermore, the performance of the curved-type system and the flat-type system with the same absorb collector area is investigated based on the weather data in Hefei, China. The main results are: (1) The curved-type system could enhance the electrical yield and heat gain by the PV/T balcony according to the analysis based on a sunny day and a cloudy day in summer. The enhancement would be more obvious when the proportion of beam radiation is higher. (2) The performance of the comparative systems during the non-heating season demonstrates that the curved system could improve the electrical yield, heat gain, and total exergy. (3) The parametric analysis indicates that the curved system with a bigger central angle and facing south performs better.

Building integrated photovoltaic/thermal technologies in Middle Eastern and North African countries: Current trends and future perspectives

Statistics show that developed countries already host a significant number of building integrated photovoltaic/thermal (BIPV/T) systems, but developing countries, including many Middle Eastern and North African (MENA) countries, are rapidly catching up. Therefore, this review provides an overview of BIPV/T systems and development plans for MENA countries via (i) a region-based literature survey that specifically differentiates between MENA and non-MENA countries, and (ii) a quantitative statistical analysis of existing work from multiple different perspectives. First, the state of the art is reviewed with a focus on the available BIPV/T technologies, heat transfer media, energy storage systems, and potential installation locations on buildings. Then, various simulation and modeling techniques are critically examined from technical, economic and environmental standpoints. Current trends and future perspectives, including barriers and challenges, in different MENA countries are discussed with reference to future global energy and environmental targets, such as achieving carbon neutrality. Finally, a comparison with other countries is made, revealing that analytical modeling is the most common approach. Moreover, energy analysis is found to be used more than any other type of analysis, while batteries and phase change materials are the favorites for electrical and thermal energy storage, respectively. Conducting more detailed economic and environmental assessments is suggested as a possible avenue for future work.

Model predictive control of air-based building integrated PV/T systems for optimal HVAC integration

High performance of HVAC connected Building Integrated Photovoltaic/Thermal (BIPV/T) systems relies on appropriate control. However, optimal control is often overlooked, resulting in systems that operate inefficiently. This paper investigates how model predictive control (MPC) can improve the operation of open loop air-based BIPV/T systems connected to multiple thermal applications.The BIPV/T system at the first institutional net-zero energy building in Canada, the Varennes library, is used as an archetype. The BIPV/T covers 16% of the south-facing roof and operates under a simple rule-based control strategy. The developed control and design strategies consider variations of this system, to achieve higher thermal utilization efficiency.A control-oriented BIPV/T model is developed and calibrated using monitored data. The BIPV/T airflow is regulated through MPC for simultaneous heat supply to an Energy Recovery Ventilator and air-to-water heat pump. The BIPV/T air flow is efficiently controlled, considering the connected thermal applications, environmental conditions, and PV temperature. Model-based control for BIPV/T systems can increase the amount of useful heat and reduce PV overheating. The MPC controller for the examined system reduced the building energy consumption compared to the business-as-usual operation by 40% and together with increased BIPV/T area can supply excess heat to adjacent buildings.

Performance simulation and analysis of a multi-energy complementary energy supply system for a novel BIPVT nearly zero energy building

Building integrated photovoltaic–thermal (BIPVT) technology is an efficient form of solar energy utilization, which realizes self-energy supply and holds good development prospects. In this paper, a novel BIPVT module based on micro heat pipe array and BIPVT near-zero energy building are proposed. A matching multi-energy complementary energy supply system is also proposed for this building. The building and energy supply system models were built using TRNSYS. The load characteristics of BIPVT buildings were studied by analyzing the heat transfer process of BIPVT components. The energy-saving rate of the building was also calculated using the method of near-zero energy building evaluation index. The accumulated cooling load and heating load of the buildings throughout the year show that those of the BIPVT buildings are 8.6% higher than those of the benchmark building. Comparison of the energy consumption results shows that the annual cumulative energy consumption of the BIPVT building is 32.3% lower compared to the benchmark building’s. In addition, 61.2% of the energy required for year-round refrigeration, heating, and electricity can be supplied by this system. The energy consumption index of the BIPVT building is 70.26 kWh / (m2 • a). Compared with the benchmark building, the BIPVT building energy saving rate is 76.6% and the building energy efficiency improvement rate is 32.3%.

Performance comparison and risk assessment of BIPVT-based trigeneration systems using vapor compression and absorption chillers

A building integrated photovoltaic-thermal (BIPVT) system, which generates both electrical and thermal energy, is an encouraging technique to significantly reduce building energy consumption. This paper compares the thermoelectric performance of two BIPVT-based trigeneration systems using vapor compression and absorption chillers for supplying the cooling load of the building. Dynamic simulation of the system performance using TRNSYS shows that the annual electrical solar fraction of the system is on average 6% higher using an absorption chiller in comparison with using a vapor compression chiller; whereas, the annual thermal solar fraction of the system is 27% lower using absorption chiller than that using vapor compression chiller. It is also found that although the electrical energy generation by the two systems is slightly different, the thermal energy generation of the system using a vapor compression chiller is about 5.5% less than that using an absorption chiller, due to the consumption of more thermal energy of the absorption chiller and thus, better cooling of the photovoltaic panels. The deterministic economic analysis indicates that despite the higher coefficient of performance of the vapor compression chiller, the payback time of the system with the absorption chiller is 4 years lower than that with the vapor compression chiller, in which the hot water generated by the system in warm months is useless. The stochastic economic analysis based on the Monte Carlo algorithm shows that the probability of the net present value of the system with an absorption chiller and a vapor compression chiller is 98.42% and 70.83%, respectively. The probability of the internal rate of return of the system with an absorption chiller and with vapor compression is also 24% and 20%, respectively. All indicators show that using the absorption chiller in the proposed trigeneration system is far less risky than using a vapor compression chiller.

Comparison analysis of the glazed and unglazed curved water-based PV/T roofs in the non-heating season

Curved tile rooftops are a characteristic design in traditional Chinese architecture. Building-integrated photovoltaic/thermal (BIPV/T) systems could realize electricity generation and energy conversion, but the common flat-type structure could not integrate with the curved rooftops while keeping the architectural features. This study proposed a curved water-based PV/T roof combined with flexible PV cells to generate electricity, provide hot water in the non-heating season, and maintain the curved roof structure. An integrated polymethyl methacrylate (PMMA) cover was installed on the comparative test rig to investigate its influence on the system's performance. Numerical models were established to describe comparative systems' behavior and validated by experimental data. The results showed that PMMA cover would increase the system's thermal efficiency and decrease the electrical efficiency (electrical efficiency: 5.56% for the unglazed system and 4.80% for the glazed system; thermal efficiency: 33.32% for the unglazed system and 56.01% for the glazed system). Among non-heating seasons, the electrical yield, heat gain and exergy by the unglazed system are 82.49 kWh, 288.29 kWh and 87.87 kWh, while those by the glazed system are 67.21 kWh, 506.93 kWh and 83.67 kWh respectively. Influence of PMMA cover's extinction coefficient and the curvature of the PV/T unit is discussed.

Techno-economic evaluation of a hybrid photovoltaic system with hot/cold water storage for poly-generation in a residential building

There is a growing effort towards the application of solar technologies to meet electrical and thermal demand. However, substantial energy is used in buildings around the world for electricity and thermal comfort. Here we evaluate a novel hybrid solar-powered system for reducing the load on the direct expansion and heat pump unit of a combined heating and air conditioning system while generating electricity. The system combines rooftop photovoltaic (PV) and building-integrated photovoltaic thermal (BIPV/T) systems for electricity generation, while any excess electricity is used to drive a hot and cold water storage system. A residential building in Tehran is used as a case study, and the results are computed via MATLAB, TRNSYS, and Carrier HAP software. The system is shown to outperform both rooftop PV and BIPV/T systems alone, generating at least 50% more electricity while reducing the heating and cooling loads on the machinery by at least 60%. The system also enjoys a payback time of 2.87 years. The impact of thermal comfort setpoints, in addition to inflation and discount rates, are also evaluated via a sensitivity analysis involving several key performance metrics, namely the hot and cold water storage volumes, the size of the desiccant wheel, and the payback time. The cooling load is found to have the greatest influence on the cold water storage volume and the desiccant size, with 80.1% and 41.2% variations for baseline variations of ±20%. With a 57.7% increase, the heating load is found to have the biggest influence on the hot water storage volume. With a 27.1% variation, inflation has the strongest effect on the payback time.

A Road Map to Detect the Foremost 3E Potential Areas for Installation of PV Façade Technology Using Multi-Criteria Decision Making

A procedure to prioritize the cities to utilize a building integrated photovoltaic thermal (BIPV/T) system is proposed in which the technique for order of preference by similarity to ideal solution (TOPSIS) is employed as a systematic decision-making method. Electricity generation and heat recovery in a year from the energy side, levelized cost of electricity (LCOE), and payback period (PBP) from the economic viewpoint, as well as the carbon dioxide savings from the environmental perspective, are taken into account as the decision criteria. They are the key economic, environmental, and energy (3E) performance indicators of the system. The novelty of the proposed research approach is two items. The first item is systematic and could be employed for each and every case. Moreover, another item is that selection is made based on energy, economic, and environmental (3E) criteria all together, as the important aspects of an energy system. Having introduced the procedure, it is utilized to rank five cities in Iran for the installation of BIPV/T technologies. The cities are Tehran, Tabriz, Yazd, Rasht, and Bandar Abbas, where each one is a populated city from one of the climatic conditions of the country. According to the results, a high priority is seen for two cities: the first city is Yazd with the highest ambient temperature and relative humidity among the alternatives, and the other city is Tehran, with the highest natural gas and electricity tariffs, as well as the greatest price for operating and maintenance. The values of heat recovery, electricity generation, carbon dioxide savings, PBP, and LCOE for Yazd are 42.3 MWh, 23.4 MWh, 16.8 tons, 5.48 years, and 9.45 cents per kWh. The corresponding values for Tehran are 35.6 MWh, 21.6 MWh, 15.0 tons, 2.79 years, and 8.71 cents per kWh, respectively.

Performance study of air-type BIPVT coupled water-cooled wall

Building-integrated photovoltaic-thermal (BIPVT) systems can provide both electrical and thermal energy for building, realizing efficient use of solar power and decreasing the energy consumption of the building. In this study, water-cooled walls were installed on both sides of the air flow channel to improve the heat exchange between the photovoltaic (PV) panels and the air by cooling the air, thus realizing an improvement in the thermal/electrical performance of air-type BIPVT. An experimental system of coupled BIPVTs was conducted to study the influence of cooling water temperature on performance of the system. The results show that a 10 K reduction in cooling water temperature increases the heat efficiency by 26% and the electrical efficiency by approximately 2%. The results can be used for the optimized operation of BIPVT system.