Solar Thermal Water Heating System Research Articles

Design and simulation of efficient solar thermal water heating system for textile industries in Pakistan

Pakistan is facing a severe crisis of energy since 2004. The core causes behind this crisis of energy are the lack of usage of advanced tools in policy development and planning, poor governance and dependency on other sources of energy which are also limited. In this research the design of a solar thermal system to produce hot water at a specified temperature has been presented as solar energy is available in abundance. A flow rate of 80 tons per day of hot water has been assumed. This system may run for 16 hours a day and it will require 5 tons of water per hour at the input. Water at ambient temperature of 25℃ enters the system and hot water at 75℃ is produced by the system. This design is implemented on TRNSYS software which validates the temperature achievement of 75℃ at outlet. It is shown that the collector area of flat plate solar collectors is 600m2. This temperature configuration is an essential requirement for textile industry and it is achieved efficiently. It is a good replacement for the industry working with expensive energy sources like diesel, gas or furnace oil.

Design improvement of a laboratory prototype for efficiency evaluation of solar thermal water heating system using phase change material (PCMs)

Thermal energy in the solar thermal energy storage system cannot be stored for a long time during the evening hours as well as days that have minimal sunlight due to heat transfer to the surrounding atmosphere. PCMs are being implemented into these storage systems to enhance the thermal storage capacity of solar energy. PCMs based latent heat storage technique can extend thermal energy storage over long periods due to its ability to store energy. Several different types of PCMs with various chemical compounds and melting temperatures can suit various thermal storage applications in real life. However, the concept of combining these PCMs types with different ratios is an area within this field that has not yet been investigated as it is time-consuming and a matter of numerous combinations and trials. A model solar thermal energy storage system with the flexibility to test different PCM's blends can omit the problem. This research work intended to propose a design as testing apparatus that can successfully operate and investigate the different PCM's blends to find the optimum ratios for a highly efficient solar thermal water heating system. An appropriate laboratory-sized prototype design has described that can replicate the functions of a solar thermal water heating system. The necessary assumptions and mathematical relations are also presented for the proposed design.

Design of Solar Water Heater Using Collector Cylindric Parabolic and Coil Heater as Absorber at Focus Point

Solar thermal water heating systems have been developed to replace conventional heating. Therefore, the design of a parabolic cylinder collector-type solar heating unit with a coil-shaped heater (absorber) has been carried out. The cylindrical collector is made of an aluminum plate covered with a reflective sticker and the base is insulated, having a diameter, height, length, and position of the focal point 150, 60, 200, and 22.4 cm, respectively. The coil water heater of 3/8-inch diameter copper pipe having a diameter, pitch, and length of 20, 3, and 200 cm, respectively. The concentration ratio between collector area and heating pipe area (absorber) is 3.6. The results of heating trials conducted from 10:00 to 16:00 WIT, in Duplo to 100 liters of water circulated through the heating pipe at a speed of 0.017 kg/sec, indicate that heating is affected by fluctuations in radiation intensity. Thermal efficiency is inversely proportional to heating time. the lower the time when the difference between the temperature of the incoming and outgoing water gets smaller, or in other words in the evening the water temperature approaches a steady state. The achieved maximum water-heating temperature is 53C in the average radiation range during the test is 687-693 W/m2.

Disinfection of Fecal Sludge Using Solar Thermal Water Heating: Sludge Management Option for Developing Countries

AbstractThis study investigates a solar thermal water heating system that is effective in drying and disinfecting fecal sludge (FS) and recovering nutrients and water resources that happen to have ...

Solar driven water heating systems for medium-rise residential buildings in urban mediterranean areas

International Energy Agency reported that buildings are accountable for one-third of the global final energy demand in 2017. On-site renewable energy generation can reduce buildings' grid electricity consumptions. Medium-rise buildings located in urban areas have limited available rooftop or facade surfaces, thus solar driven technologies such as solar thermal, photovoltaics (PV) or photovoltaics/thermal (PV/T) are in competition for the available space. This investigation aims to compare available solar driven water heating systems in the market, suitable to replace the conventional electric water heater for a multi-residential building. Under the present study, solar PV electric water heating system (S1), solar thermal water heating system with electric boosting (S2), solar PV/T water heating system with electric boosting (S3) and integrated solar PV and heat pump water heating system (S4) are investigated. The performance parameters compared are the annual net electricity consumption from the grid and the net present value of life-cycle cost (LCC) for 20 years life. Results reveal that S3 and S4 have ‘net’ positive electricity production but higher initial costs, compared to the other systems. For buildings located in colder climates, S2 has lower LCC compared to S3 but for warmer climates the LCC of S3 is the lowest.

Development of a dairy multi-objective optimization (DAIRYMOO) method for economic and environmental optimization of dairy farms

The aim of this paper was to develop a Dairy Multi-Objective Optimization (DAIRYMOO) method to carry out multi-objective optimization of dairy farm equipment, management practices and electricity tariffs, optimizing based on a user specified economic and environmental weighting factor. Models of both solar thermal water heating and heat recovery systems were developed, validated, and used as part of a test case for DAIRYMOO. Optimizing dairy farm equipment, management practices and electricity tariffs both economically and environmentally is necessary because of the competing goals of increasing farm milk production and the necessity to reduce agricultural related greenhouse gas emissions. Models of solar thermal water heating and heat recovery systems were created using experimental data to evaluate the economic and environmental performance of these technologies. Multi-objective optimization was used to obtain the optimal selection of equipment, management practices and electricity tariffs which impact electricity related costs and CO2 emissions, based on a user specified economic and environmental weighting factor. A Genetic Algorithm was employed to maximize a combined objective function based on this weighting factor. For a test case with a 195 cow farm, over a ten year time horizon the optimal equipment, management and electricity tariff combination was found using 11 different weighting factor values ranging from 0 to 1. The combined objective function was gradually weighted towards the environmental criterion and away from the economic criterion. It was found that the optimal equipment combination changed incrementally relative to the change in the weighting factor. Furthermore, an analysis was carried out which performed the same multi-objective optimization on the same 195 cow farm, but with a mandatory real time pricing tariff in place. The optimal configurations using the mandatory real time pricing tariff showed that gas water heating was selected regardless of the weighting factor employed. This differed from the results with no mandatory tariff in which a day/night tariff was optimal for all weighting factor values, and electric water heating was optimal for weighting factor values of 0.9 or higher i.e. when the combined objective function was weighted heavily towards the economic criterion. For both analyses, heat recovery systems were not included in the optimal farm configuration unless the weighting factor was 0.2 or less, indicating that the economic performance of these systems was poor. Solar thermal water heating systems were not included in the optimal farm configuration regardless of the weighting factor value. The DAIRYMOO method described in this study will provide useful advice to farmers and policy makers relating to economic and environmental optimization around equipment, management and electricity tariff choices on dairy farms.

Off-grid solar thermal water heating system using phase-change materials: design, integration and real environment investigation

A solar thermal water heating system using a custom-built latent heat storage tank with paraffin wax, puretemp68 and stearic acid/palmitic acid eutectic mixture based phase-change materials was designed, developed and its performance evaluated in real-time. The fully autonomous off-grid solar thermal water heating system was packaged by integrating solar thermal collector, phase change material tank, photovoltaic modules, operational controller, circulation pumps and battery, along with a data logger. A water-glycol with anti-freeze characteristics with efficient energy storage in cold weather was employed as heat transfer fluid for solar thermal energy harvesting for charging and discharging of phase change materials to heat the water tank. Solar charge-discharge and water charging results with phase change materials during May to October 2018 (Mesa, AZ 85212, USA) showed that the stearic acid/palmitic acid eutectic mixture outperformed the paraffin wax and exhibited comparable performance with puretemp68 storage system. The efficiency of water charging from stearic acid/palmitic acid (55%) is higher compared to that from paraffin wax (20%) and better than puretemp68 (45%). Even though, the paraffin wax melts quickly during charging, it exhibited super-cooling behavior during discharging, leading to incomplete discharge. The storage energy density of stearic acid/palmitic acid (∼0.48 MJ kg−1) is comparable to puretemp68 with uniform thermal energy distribution inside the storage container due to higher thermal conductivity and lower melting point. The solar thermal water heating system demonstration proved that the domestic hot water system using stearic acid/palmitic acid could be a practical solution for effectively harvesting solar thermal energy for rural areas.

An experimental study of solar thermal system with storage for domestic applications

Building sector consumes a greater portion of energy for heating and cooling applications. The utilization of fossil fuels for space and water heating in buildings cause a negative effect on the environment by producing larger CO2. In this study solar thermal water heating system for building application have been analyzed from the first and second law perspectives of thermodynamics considering various scenarios and water consumption pattern. The solar flat collector is very commonly used to extract energy from sunlight. Therefor energy and exergy efficiency curves for the solar flat collector were presented. The energetic and exergetic values for the system were calculated based on the experimental values for the overall system, the heat exchanger and the pumps using the approach of exergetic product/fuel basis. The greatest and lowest relative irreversibility’s occurred at the solar collector and the heat exchanger with values of 85.73% and 2.45%, respectively, and the system overall exergy efficiency was determined to be 20.28%. The energy and exergy efficiencies of the solar collector were analyzed at three different cases depending on the mass flow rates in the solar collector and the secondary circuit of the system. Three different mass flow rates were applied to the inlet of the secondary circuit to observe the efficiency effect on the solar collector circuit. This study can assist in selecting a proper solar collector and storage size for buildings of various capacity and possible improvement in the design of the system components.

Design, Fabrication, and Efficiency Study of a Novel Solar Thermal Water Heating System: Towards Sustainable Development

This paper investigated a novel loop-heat-pipe based solar thermal heat-pump system for small scale hot water production for household purposes. The effective use of solar energy is hindered by the intermittent nature of its availability, limiting its use and effectiveness in domestic and industrial applications especially in water heating. The easiest and the most used method is the conversion of solar energy into thermal energy. We developed a prototype solar water heating system for experimental test. We reported the investigation of solar thermal conversion efficiency in different seasons which is 29.24% in summer, 14.75% in winter, and 15.53% in rainy season. This paper also discusses the DC heater for backup system and the current by using thermoelectric generator which are 3.20 V in summer, 2.120 V in winter, and 1.843 V in rainy season. This solar water heating system is mostly suited for its ease of operation and simple maintenance. It is expected that such novel solar thermal technology would further contribute to the development of the renewable energy (solar) driven heating/hot water service and therefore lead to significant environmental benefits.

Artificial intelligence techniques based on aquaculture solar thermal water heating system control

Artificial intelligence techniques based on aquaculture solar thermal water heating system control

Solar Thermal Aquaculture System Controller Based on Artificial Neural Network

Temperature is one of the most principle factors affects aquaculture system. The water temperature is very important parameter for shrimp growth. It can cause stress and mortality or superior environment for growth and reproduction. The required temperature for optimal growth is 34oC, if temperature increase up to 38oC it causes death of the shrimp, so it is important to control water temperature. Solar thermal water heating system is designed to supply an aquaculture pond with the required hot water in Mersa Matruh in Egypt as presented in this paper. This paper introduces a complete mathematical modeling and MATLAB SIMULINK model for the solar thermal aquaculture system. Moreover the paper presents the control of pond water temperature using artificial intelligence technique. Neural networks are massively parallel processors that have the ability to learn patterns through a training experience. Because of this feature, they are often well suited for modeling complex and non-linear processes such as those commonly found in the heating system. They have been used to solve complicated practical problems. The simulation results indicate that, the control unit success in keeping water temperature constant at the desired temperature by controlling the hot water flow rate.

Solar Thermal Aquaculture System Controller Based on Artificial Neural Network

Temperature is one of the most principle factors affects aquaculture system. The water temperature is very important parameter for shrimp growth. It can cause stress and mortality or superior environment for growth and reproduction. The required temperature for optimal growth is 34oC, if temperature increase up to 38oC it causes death of the shrimp, so it is important to control water temperature. Solar thermal water heating system is designed to supply an aquaculture pond with the required hot water in Mersa Matruh in Egypt as presented in this paper. This paper introduces a complete mathematical modeling and MATLAB SIMULINK model for the solar thermal aquaculture system. Moreover the paper presents the control of pond water temperature using artificial intelligence technique. Neural networks are massively parallel processors that have the ability to learn patterns through a training experience. Because of this feature, they are often well suited for modeling complex and non-linear processes such as those commonly found in the heating system. They have been used to solve complicated practical problems. The simulation results indicate that, the control unit success in keeping water temperature constant at the desired temperature by controlling the hot water flow rate.

Improving the energy performance of UK households: Results from surveys of consumer adoption and use of low- and zero-carbon technologies

This paper presents results from a UK Open University project which surveyed consumers’ reasons for adoption, and non-adoption, of energy efficiency measures and renewable energy systems—collectively called low- and zero-carbon technologies—and their experiences of using these technologies. Data were gathered during 2006 via an online questionnaire with nearly 400 responses, plus 111 in-depth telephone interviews. The respondents were mainly environmentally concerned, ‘green’ consumers and therefore these are purposive rather than representative surveys. The paper outlines results for four energy efficiency measures (loft insulation, condensing boilers, heating controls and energy-efficient lighting) and four household renewables (solar thermal water heating, solar photovoltaics, micro-wind turbines and wood-burning stoves). These green consumers typically adopted these technologies to save energy, money and/or the environment, which many considered they achieved despite rebound effects. The reasons for considering but rejecting these technologies include the familiar price barriers, but there were also other obstacles that varied according to the technology concerned. Nearly a third of the surveyed consumers had adopted household renewables, over half of which were wood stoves and 10% solar thermal water heating systems. Most adopters of renewables had previously installed several energy efficiency measures, but only a fifth of those who seriously considered renewables actually installed a system. This suggests sell energy efficiency first, then renewables. There seems to be considerable interest in household renewables in the UK, especially among older, middle-class green consumers, but so far only relatively few pioneers have managed to overcome the barriers to adoption.

A Photovoltaic Solar Water Heating System

A novel solar water heating system was patented in 1994. This system uses photovoltaic cells to generate electrical energy that is subsequently dissipated in multiple electric resistive heating elements. A microprocessor controller continually selects the appropriate heating elements such that the resistive load causes the photovoltaic array to operate at or near maximum power. Unlike other residential photovoltaic systems, the photovoltaic solar water heating system does not require an inverter to convert the direct current supplied by the photovoltaic array to an alternating current or a battery system for storage. It uses the direct current supplied by the photovoltaic array and the inherent storage capabilities of a residential water heater. A photovoltaic solar hot water system eliminates the components most often associated with the failures of solar thermal hot water systems. Although currently more expensive than a solar thermal hot water system, the continued decline of photovoltaic cell prices is likely to make this system competitive with solar thermal hot water systems within the next decade. This paper describes the system, discusses the advantages and disadvantages relative to solar thermal water heating systems, reviews the various control strategies which have been considered, and presents experimental results for two full-scale prototype systems.