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The design of a solar thermal installation is based on the lowest irradiance levels that occur during winter. However, there are consecutive days with irradiance levels well below those used for the design, which are called in this work "critical irradiance levels". To solve this challenge, a statistical analysis is carried out to find a representative percentile of 22 years of consecutive days with "critical irradiance levels". A case study of a cotton-dyeing industrial process requires 18.5 m3 of hot water and operates for 2.75 h at temperatures between 40 and 90 °C. Environmental variables for 22 years were analyzed and validated to design a solar thermal installation (solar collector network and storage system) and a coupled heat pump. The fifth percentile, with three consecutive days and low irradiance levels, was the most repetitive. For this case, a storage system of 46.5 m3 guaranteed heat load at target temperature. The simple payback was 14.1 years, and the energy cost was 0.094 USD/kWh, which was competitive against the energy cost from using fossil fuels, 0.064 USD/kWh. The design based on critical environmental conditions guarantees a continuous supply of energy to the industrial process and defines the minimum availability of solar energy to supply a process. [ABSTRACT FROM AUTHOR]

Currently, most of the thermal and electrical energy for industrial processes is generated from fossil fuels. Solar thermal energy has unlimited potential to supply thermal and electrical energy for low-temperature industrial processes and has demonstrated the ability to replace the use of fossil fuels partially or totally. The implementation of solar thermal energy systems in industrial processes must be accompanied by a long-range economic analysis that allows evaluation of the benefit obtained during its useful life. The Life Cycle Cost method evaluates the costs associated with the solar thermal system during its operating period and allows for determining the system design that presents the best effective cost. This work presents the Life Cycle Cost analysis (LCCA) of a solar thermal system and an organic Rankine cycle (ORC) driven by solar energy for the supply of thermal and electrical energy to a cotton dyeing process. The LCCA considered the costs of installation, operation, maintenance, services, and basic components, based on the solar fraction supplied to the process by the solar thermal system and the ORC. The results obtained show that the solar fraction that maximizes the effective cost of the thermal system and the ORC powered by solar thermal energy is 1.0. The effective cost of thermal energy reaches 706,413 USD, and for electrical energy, this cost amounts to 1,125,386 USD. The levelized cost of thermal energy, when the best effective cost is presented, is 0.035 USD/kWhth, while electric energy presents a levelized cost of 0.103 USD/kWhe. [ABSTRACT FROM AUTHOR]

The low-temperature solar thermal facility presents important challenges that must be solved to guarantee the heat load and target temperature by means of a parametric analysis that defines the design, operation, and performance of a solar-assisted heat pump. Through the analysis, objectives such as minimum total cost, zero emissions, and a competitive kWh cost can be reached. In this work, a multiparameter study was carried out for a system made up of low temperature solar thermal source and a heat pump to define the operation and performance, using a case study of 2nd generation (2G) bioethanol production. Together, these devices define the system design and must guarantee the operation of the industrial process. One of the system designs seeks to achieve the lowest cost of energy (LCOE = 0.101 USD/kWh) and deliver a heat flow of 637 kW with a temperature of 105 °C for 16 h; the heat pump must work with a heat source of 40 °C and a coefficient of performance (COP) of 3.5 with the refrigerant R1234ze(z). Another of the system designs seeks to achieve the best performance of the heat pump, which was obtained with a COP= 5.1. Its operating conditions are reached when the heat source is 60 °C, and the compression work is 125 kW using the refrigerant R1336mzz(E). The system levelized cost of energy is 0.124 USD/kWh. The importance of this work lies in the fact that a parameter evaluation allows to know the relevant objectives of the system, previous the design to make a custom suit. [ABSTRACT FROM AUTHOR]

Solar thermal energy can supply the total or partial thermal load in low-temperature industrial processes. In industry, applications of solar thermal energy may extend to produce electric power and refrigeration in a viable way. This work proposes a solar system composed by a storage system, low-temperature solar collector field, an organic Rankine cycle, and an absorption refrigeration system (Water/Lithium Bromide) to produce electric power and refrigeration. To evaluate the system performance, and its thermal and economic feasibility, an analysis, both in a continuous process and in a batch process, of a food industry was conducting. By this way, was possible to find operating conditions based on competitive cost of energy and decreasing CO2 emissions. An absorption refrigeration system with a thermal load value of 176 kW, and a thermal performance coefficient (COP) of 0.87, had a thermal solar energy levelized cost (LCOEth) of 0.0588 USD per kWh. ORC electric energy (LCOEele) had a charge of 0.1089 USD per kWh and a thermal efficiency of 0.11. Energy costs in kWh showed to be competitive, since they are in the order of the prices of conventional sources of energy, additionally, the emissions can reduce to zero. [ABSTRACT FROM AUTHOR]

Low-temperature solar thermal facilities face challenges like large storage systems and solar intermittence. This drives the development of novel storage systems that also implies lower costs. This study proposes the coupling of a low-temperature solar storage system that feeds heat of vaporisation to a heat pump; the pump, at the same time, produces higher temperature thermal energy. The heat pump let to supply heat to low and medium temperature industrial processes in a way that volumetric requirements decrease, compared against using a conventional solar thermal storage system. Using the coolant trans-1,3,3,3-tetrafluoroprop-1-ene like working fluid in the heat pump, it is possible to obtain storage volumes up 30 m3 to supply 4,400 kWh of heat process. This contributes to decrease in 44 % the volume of a conventional storage system. Reducing the installation surface, in turn reduces the costs and the solar thermal systems payback time. These achievements, overall, enable to reach a feasible system that is competitive in front of the fossil fuels costs, reducing or eliminating the environment impact of burning fossil fuels. [ABSTRACT FROM AUTHOR]

A study of cubic splines and Fourier series as interpolation techniques for filling in missing hourly dam in energy and meteorological time series data sets is presented. The procedure developed in this paper is based on the local patterns of the data around the gaps. Artificial gaps, or 'pseudogaps,' created by deleting consecutive data points firm the measured data sets, were filled using four variants of the cubic spline technique and 12 variants of the Fourier series technique. The accuracy, of these techniques was compared m the accuracy of results obtained using linear interpolation to fill the same pseudogaps. The pseudogaps filled were 1--6 data points in length created in 18 year-long sets of hourly energy use and weather data. More than 1000 pseudogaps of each gap length were created in each of the 18 data sets and filled using each of the 17 techniques evaluated. Use of mean bias error as the selection criterion found that linear interpolation is superior to the cubic spline and Fourier series methodologies for filling gaps of dry bulb and dew point temperature time series data. For hourly building cooling and heating use dam, the Fourier series approach with 24 data points before and after each gap and sLy terms was found to be the most suitable; where there are insufficient data points to apply this approach, simple linear interpolation is recommended. [DOI: 10.1115/1.2189872]

Currently most of the energy production is supported by fossil fuels, however, renewable sources contribution on worldwide demand of energy has been in constantly growth. One of the main challenges in the use of solar thermal energy in industrial processes is their cost, especially when is compared to energy generation by fossil fuels. This cost delimits the investment payback time for a thermo-solar installation to be feasible. This fact makes crucial the development of methodologies for the integration of solar energy for large-scale industrial applications. This work deals with the thermo-economic evaluation of the heat and power production through a low-temperature flat-plate solar collector system. Also, strategies were developed to increase energy efficiency by evaluating different process integration scenarios. The proposed strategies for energy efficiency combined with renewable energy were applied to an integrated solar thermal energy system into a 1G and 2G (first and second generation) bioethanol process from sugarcane. It was found that to replace the fully process heat and power with low-temperature solar thermal energy, a heat recovery network ∆𝑇𝑚𝑖𝑛 of 5 °C, a heat duty of 131 kW and a supply temperature of 105 °C are required. All these results lead to a cost of 0.2112 USD/kWh of the integrated system. The power system operates independently by mean an Organic Rankine Cycle and the heating system is supplied by a solar collector network with a cost of 0.0477 USD/kWhele. Currently most of the energy production is supported by fossil fuels, however, renewable sources contribution on worldwide demand of energy has been in constantly growth. One of the main challenges in the use of solar thermal energy in industrial processes is their cost, especially when is compared to energy generation by fossil fuels. This cost delimits the investment payback time for a thermo-solar installation to be feasible. This fact makes crucial the development of methodologies for the integration of solar energy for large-scale industrial applications. This work deals with the thermo-economic evaluation of the heat and power production through a low-temperature flat-plate solar collector system. Also, strategies were developed to increase energy efficiency by evaluating different process integration scenarios. The proposed strategies for energy efficiency combined with renewable energy were applied to an integrated solar thermal energy system into a 1G and 2G (first and second generation) bioethanol process from sugarcane. It was found that to replace the fully process heat and power with low-temperature solar thermal energy, a heat recovery network ∆𝑇𝑚𝑖𝑛 of 5 °C, a heat duty of 131 kW and a supply temperature of 105 °C are required. All these results lead to a cost of 0.2112 USD/kWh of the integrated system. The power system operates independently by mean an Organic Rankine Cycle and the heating system is supplied by a solar collector network with a cost of 0.0477 USD/kWhele. [ABSTRACT FROM AUTHOR]

The building peak cooling load calculation is one of the fundamental steps to develop a proper whole-building HVAC system design. The accuracy of the calculation not only impacts the system size but also influences the building's performance over the long run since oversized or undersized HVAC systems can exhibit less than optimal operation. Therefore, an accurate, easy-to-use method has been a goal for more than 60 years in the United States. To date, ASHRAE has published five methods for determining building peak cooling loads, including the total equivalent temperature difference/time averaging (TETD/TA) method, the transfer function method (TFM), the cooling load temperature difference/solar cooling load/cooling load factor (CLTD/SCL/CLF) method, the heat balance method (HBM), and the radiant time series method (RTSM). This article presents the results of a comprehensive comparison of these building peak cooling load calculation methods with a focus on the sensible building envelope cooling loads. The results show that the HBM is the most accurate method, followed by the RTSM, the TFM, the TETD/TA method, and the CLTD/SCL/CLF method. [ABSTRACT FROM AUTHOR]