Optimal management proposal for hybrid water heating system (original) (raw)
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Optimizing a mixed water heating system (solar and electric) for rural areas
Acta Scientiarum. Technology, 2013
The increasing consumption of electric energy used for heating water especially in peak periods, requires the use of alternative energy sources that meet the same needs being less costly. The use of solar energy for heating water allows reducing the demand and consumption of electric energy by a conventional electric shower. This study aimed at developing a software to simulate, design, and optimize a mixed water heating system (solar and electric), by using the software MATLAB. This software designed independently the area of a solar collector, the volume of the boiler, and the power of the auxiliary electrical resistance, in order to meet the needs of hot water and ensure the least annual cost. The optimized system when compared with the use of a conventional electric shower presented a time for return of the invested capital of around seven months.
Solar Energy, 2017
An existing solar installation located in the south of Tunisia was studied using TRNSYS software coupled with a developed model for pump mechanical power consumption calculation. First, this installation was simulated using TRNSYS software and the simulation results were compared with experimental measurements. Then, its thermal performance and economic viability was studied for different flow rates values of the primary and secondary circuits. It was found that the optimal flow rates values for maximum annual energy or net energy production are of 10 kg/hÁm 2 for primary circuit (close to average water draw flow rate value) and of 15 kg/hÁm 2 for secondary circuit (close to average water draw flow rate value during solar production period of the day). Also, it was demonstrated that the optimal flow rate value of primary circuit depends on season whereas the optimal flow rate value of the secondary circuit is independent of season only for primary circuit flow rate value strictly lower than 7.5 kg/hÁm 2. Moreover, it was noted that flow rate optimization may improve the solar installation thermal performance but it's not sufficient to fix a sanitary risk problem. Concerning pumps consumption, it was found that the primary circuits pump energy consumption can represent from 66% of total pumps energy consumption for low flow to 97% for high flow. Finally, it was concluded that investing in solar installation was more economically interesting in case of replacing an electrical existing conventional installation than a gas one. By analogy, it was concluded that using a gas auxiliary heater was more economically viable.
2009
This paper analyzes the collected data from an installed solar water heating (SWH) system at Marjeyoun, South Lebanon. The analysis provides complete weather data for the area studied with detailed weather profiling by day and month. Average annual temperature in the studied area was 18.1 oC and total annual solar insolation was measured to be 1510 kWh/m. Second, a detailed analysis of hot water consumption patterns was obtained indicating the consumer hot-water-use profile by hour, day and month. Major findings indicate that the average annual consumption of hot water is 13 m/person and 645 L/m of built area. In addition, the thermal energy imbedded in the hot water used showed consumption of 618 kWh/person and 30.9 kWh/m of built space. Third, actual solar contributions to hot water needs were quantified. The results indicate that the system contributed 3049 kWh/yr to the heating load offsetting 98.6 % of electricity needed to heat water. Total annual savings were calculated to be...
Water heating is widely spread technology used for domestic and industrial purposes. Presently water heating is still based mostly on the fossil fuels although mature and cost-effective technologies running on the renewable energy sources already exist for this purpose. Water heating systems can run on renewables purely or partially. This paper describes concept of hybrid water heating systems based on solar collectors and heat exchanger fed from centralized heat supply grid, structure and sizing of the proposed system and principles for control of solar collectors.
Energies
Renewable energy systems have received a lot of attention as sustainable technology in building sector. However, the efficiency of the renewable energy systems depends on the surrounding conditions, and it could gradually decrease by excessive and long-term operation. As a solution, a hybrid system can increase the reliability of energy production and decrease investment costs through by reducing the system capacity. The hybrid system operates at the ideal performance, but the design and operation method for hybrid system have not been established. In this paper, the performance of the hybrid system combined with photovoltaic/thermal (PVT) system and ground source heat pump (GSHP) system was analyzed using TRNSYS 17 and feasibility was assessed. The energy consumption and performance efficiency of hybrid system were calculated according to operating modes. Furthermore, seasonal performance factor (SPF) of hybrid system was compared with that of conventional GSHP system. System performance was analyzed in various conditions such as the usage of storage tank heating and set temperature for solar heating. As a result, the average SPF of the developed system increased about 55.3% compared with the GSHP system.
Hybrid Solar Heat Pump System for Water Heating
Engenharia Agrícola, 2019
A comparative test of water heating between the hybrid system-solar collector with heat pump-and a system with conventional supplementary heating-with high electric powerwas performed. For this, a small capacity heat pump was installed, which was later installed together with a solar heating system, composed of a 250 L thermal reservoir and three thermoplastic collector plates. Tests were carried out to evaluate the COP of the heat pump and the energy consumption of the solar heating system operating with the heat pump and with an electrical resistance of 3000 W. In the laboratory tests, the heat pump presented an average COP of 2.15. In the field tests, the energy consumption of the solar system with heat pump was 54.9% lower when compared to the tests in which electrical resistance was used as a source of supplementary heating.
Energies, 2021
According to the authors of this paper, the mathematical point of view allows us to see what sometimes cannot be seen from the designer’s point of view. The aim of this study was to estimate the influence of the most important parameters (volume of heat storage tanks, daily consumption of domestic hot water, optical efficiency, heat loss coefficient, and total area of a solar collector) on the thermal power output of solar domestic hot water (SDHW) system in European climatic conditions. Three deterministic mathematical models of these relationships for Madrid, Budapest, and Helsinki were created. The database for the development of these models was carried out using computer simulations made in the TRNSYS software environment. The SDHW system located at the Bialystok University of Technology (Poland) was the source of the measurement results used to validate the simulation model. The mathematical optimization procedure showed that the maximum annual useful energy output that can be...
Adomavičius V., Petrauskas G.. Optimisation of hybrid water heating system based on solar collectors and heat exchanger in order to maximize solar heat energy's share Abstract: in principle one of the main tasks for control of solar collectors in the hybrid water heating system, which is based on their combination with heat exchanger fed from the centralised heat supply grid, is to arrange operation of solar collectors in the way maximizing the capture of solar irradiation. Solution of this problem by means of programme packet for the designing of control systems Planning System 4000 is described in this paper.
2014
The use of solar thermal systems with electricity backup and heat pumps as hot water suppliers in residential buildings seems to be a very promising way to increase energy efficiency. Nevertheless, the massive adoption of such solutions in small networks (neighborhood, village) may induce problems in the electric grid management. This study explores the impact of such systems in small electric grids, using an hourly electricity backup load model. To test and validate the model, we used the island of Corvo (Azores), a small isolated community where it is being implemented a project of electrification of domestic hot water systems (DHW). We consider different load scenarios to manage the backup of DHW systems and analyze its consequences on the peak load and overall energy demand. For Corvo, for the best case where the backup is limited and distributed along off-peak hours, we observed an increase of 24% in the peak load and 7.5% in the annual energy demand. Critical values of peak load are found in winter, when daily solar irradiation is lower than 2000 Wh/m 2 /day. We conclude that the solar thermal systems are responsible for most of the peak load increase, but since they have the flexibility to adjust the electric backup hours due to the thermal storage capacity, the use of these systems can minimize the impact on the grid. Heat pumps on the other hand, albeit being more efficient in terms electric backup, are less flexible to contribute to the grid management as they operate continuously.
Hybrid renewable energy system application for electricity and heat supply of a residential building
Thermal Science, 2015
Renewable and distributed energy systems could provide a solution to the burning issue of reliable and clean supply of energy, having in mind current state and future predictions for population growth and fossil fuel scarcity. Hybrid renewable energy systems are novelty in Serbia and warrant further detailed research. The aim of this paper, is to analyze the application of renewable energy sources for electricity and heat supply of a typical household in Serbia, as well as the cost-effectiveness of the proposed system. The influence of feed-in tariff change on the value of the investment is analyzed. Small, grid-connected hybrid system (for energy supply of a standard household), consisting of geothermal heat pump for heating/cooling, solar photovoltaic panels and small wind turbine for power supply is analyzed as a case study. System analysis was conducted with the help of RETscreen software. Results of techno-economics analysis have shown that investing in geothermal heat pump and photovoltaic panels is cost-effective, while that is not the case with small wind turbine.