scholarly journals Improving the Performance of Solar Heat Collector Using Molten Salts

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Alaa H. Salum ◽  
Ban H. Ismail ◽  
Saad M. Awaad ◽  
Ammar H. Khalaf
Keyword(s):  
Storage Tank ◽  
Molten Salts ◽  
Calcium Nitrate ◽  
Freezing Temperature ◽  
Magnesium Nitrate ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Water Tank ◽  
Latent Heat Storage ◽  
Circulating Water

An individual solar collector and two partly freight cylinders filled with molten salts embedded storage tank were connected to each other and forced circulated water by electric pump to improve the thermal performance of residential solar hot water tank. Multi flow rates of 25, 50 and 70 l/h. used to achieve an appropriate flow rate of circulating water. The calcium nitrate tetra hydrate Ca(NO3)2-4H2O and magnesium nitrate hex hydrate Mg(NO3)2-6H2O were mixed to form cheap binary molten salts base on different weight ratios. These molten salts combined could be used as both sensible heat materials and latent heat storage materials, besides they can directly use as heat transfer fluid due to freezing temperature. Six samples of different mixing ratio of molten salts had tested to assess the thermal analysis of each sample. The result indicated that the mixture 60%Ca(NO3)2+40%Mg(NO3)2 had the best performance for thermal storage tank with melting point of 38°C and the thermal value is 8.7 mW, and thermal stability of molten salts were noticed by DSC 60 SHIMADZSU devise.

Experimental Testing of a Thermoelectric-Based Hydronic Cooling and Heating Device With Transient Charging of Sensible Thermal Energy Storage Water Tank

2008 ◽  
Author(s):  
Michael J. Kazmierczak ◽  
Sreenidhi Krishnamoorthy ◽  
Abhishek Gupta
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Tank ◽  
Hot Water ◽  
System Component ◽  
Water Tank ◽  
Te Modules

Experiments were performed to charge either cold or hot water thermal energy storage tanks using a heat exchanger equipped with multiple thermoelectric (TE) modules. The primary objective was to design a simple, but effective, modular Peltier heat pump system component to provide chilled or hot water for domestic use at the appliance level, and when arranged in multiple unit combinations, a system that can potentially satisfy small home cooling and heating requirements. Moreover, when the TEs are directly energized using solar PV panels, the system provides a renewable, pollution free and off-the-grid solution to supplement home energy needs. The present work focuses on the design and testing of a thermoelectric heat exchanger component that consists of two water channels machined from two aluminum plates with an array of three or five thermoelectric modules placed in between to transiently cool and/or heat the water in the thermal energy storage tank. The water passing over either the cold or hot side of the TE modules is recirculated to charge the cold or hot thermal storage tank, respectively. The temperatures in the prototype Peltier heat exchanger test component and thermal energy water storage tank were measured during both cold tank charging and hot tank charging operation. The thermal efficiencies of TE heat pump cooling/heating system are reported. The effects of TE power input, number of TE units and rate of fluid flow are studied.

scholarly journals A Parametric Study of a Hybrid Photovoltaic Thermal (PVT) System Coupled with a Domestic Hot Water (DHW) Storage Tank

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6481
Author(s):  
Madalina Barbu ◽  
George Darie ◽  
Monica Siroux
Keyword(s):  
Storage Tank ◽  
Consumer Demand ◽  
Demand Curve ◽  
Electrical Energy ◽  
Hot Water ◽  
Water Tank ◽  
Domestic Hot Water ◽  
Electrical Efficiency ◽  
Outlet Flow ◽  
The Impact

Photovoltaic-thermal panels are hybrid systems that combine the two types of conventional solar energy technologies (photovoltaic and thermal panels) and simultaneously generate both thermal and electrical energy in a micro-cogeneration system. Like any co-generation system, there is an optimal balance that can be achieved between the thermal and electrical energy produced. For this reason, it is important to establish the relationship and inter-connection between the two. Limited research is available on the cogeneration interaction in a PVT system, so the novelty of this article lies in the consideration of the entire energy system connected to the PVT panel, including the storage tank and the consumer demand curve, and the investigation of the thermal parametric variation. This study analyses the impact of the variation of some thermal parameters of a domestic hot water tank on the electrical efficiency of a photovoltaic-thermal panel. A model of a system of photovoltaic-thermal panels is built in a transient systems simulation program (TRNSYS) and a one-factor-at-a-time analysis is carried out for the cold-water main temperature, tank size, tank outlet flow and consumer demand curve. The results show that the variation of the outlet flow to the consumer has the highest impact on the electrical efficiency, of about 6.8%. The next highest impact factor is the size of the tank with a variation of 4.7%. Matching the profile of the consumer is also an important aspect. It was observed that the peak electrical efficiency occurs during peak consumer demand. Finally, the instantaneous variation of the thermal and electrical power of the system was analysed as a function of the temperature at the inlet of the photovoltaic-thermal panel.

scholarly journals Fabrication and Performance Evaluation of Cold Thermal Energy Storage Tanks Operating in Water Chiller Air Conditioning System

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4159
Author(s):  
Xuan Vien Nguyen
Keyword(s):  
Heat Transfer ◽  
Cold Storage ◽  
Storage Tank ◽  
Air Conditioning ◽  
Thermal Storage ◽  
Hot Water ◽  
Operating Costs ◽  
Heat Transfer Fluid ◽  
Storage Tanks ◽  
Air Conditioning System

In this study, cold and thermal storage systems were designed and manufactured to operate in combination with the water chiller air-conditioning system of 105.5 kW capacity, with the aim of reducing operating costs and maximizing energy efficiency. The cold storage tank used a mixture of water and 10 wt.% glycerin as a phase-change material (PCM), while water was used as heat transfer fluid (HTF). The cold storage heat exchanger was made of polyvinyl chloride (PVC). On the other hand, the thermal storage tank used water as the storage fluid with a capacity of 50 L of hot water per hour. The thermal storage did not use a pump for water transfer through the heat exchanger, so as to save energy and operating costs. In this paper, the operating parameters of the cold and thermal storage tanks are shown according to the results of experimental research, including the temperatures of cooling and heating load, heat transfer fluid, and cold storage material during the discharge process, as well as the discharge duration. The system assisted the air conditioner in cooling the internship workshop space at the university with an area of 400 m2, contributing to a remarkable reduction in air-conditioning system operating costs during the daytime. Furthermore, the system recovered waste heat from the compressor of the water chiller, and a thermal storage system was successfully built and operated, providing 50 L of hot water at a temperature of 60 °C per hour to serve the everyday needs of school students. This design was suitable for the joint operation of cold and thermal storage tanks and the water chiller air-conditioning system for cooling and heating applications.

Effect of Circular Fins on Latent Heat Storage to Enhance Solar Water Heater, an Experimental Study

2015 ◽  
Vol 787 ◽  
pp. 13-17 ◽  
Author(s):  
G. Murali ◽  
K. Mayilsamy
Keyword(s):  
Energy Efficiency ◽  
Energy Storage ◽  
Storage Tank ◽  
Water Tank ◽  
Solar Water Heater ◽  
Water Heater ◽  
Latent Heat Storage ◽  
Solar Water ◽  
Collector Efficiency ◽  
Charging Energy

In natural circulation solar water heating, the efficiency of energy storage and solar collector can be improved if the water tank is stratified. Employing Phase Change Material (PCM) in the top of the tank will improve the stratification of the energy storage tank. Current paper studies the use of circular fins around PCM geometry with high surface to volume ratio to improve the efficiency of solar water heater. Heating and cooling tests have been performed in a domestic water heater with flat plate collector under real working conditions. Eventually the temperature distribution along the height of the storage tank, charging energy efficiency, collector efficiency have been calculated and compared. Tests have been simulated in CFD software for validating results. Addition of circular fins around PCM produces up to 5% and 36.48% improvement in tank charging energy efficiency, collector efficiency respectively because of improved heat transfer between PCM and water.

Experimental Testing of a Thermoelectric-Based Hydronic Cooling and Heating Device With Transient Charging of Sensible Thermal Energy Storage Water Tank

2009 ◽  
Vol 1 (4) ◽  
Author(s):  
Michael J. Kazmierczak ◽  
Sreenidhi Krishnamoorthy ◽  
Abhishek Gupta
Keyword(s):  
Energy Storage ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage Tank ◽  
Hot Water ◽  
System Component ◽  
Water Tank ◽  
Te Modules

Experiments were performed to charge either cold or hot water thermal energy storage tanks using a heat exchanger equipped with multiple thermoelectric (TE) modules. The primary objective was to design a simple, but effective, modular Peltier heat pump system component to provide chilled or hot water for domestic use at the appliance level, and when arranged in multiple unit combinations, a system that can potentially satisfy small home cooling and heating requirements. Moreover, when the TEs are directly energized using solar photovoltaic (PV) panels, the system provides a renewable, pollution-free, and off-the-grid solution to supplement home energy needs. The present work focuses on the design and testing of a thermoelectric heat exchanger component that consists of two water channels machined from two aluminum plates with an array of three, five, or eight thermoelectric modules placed in between to transiently cool and/or heat the water in the thermal energy storage tank. The water passing over either the cold or hot side of the TE modules is recirculated to charge the cold or hot thermal storage tank, respectively. The temperatures in the prototype Peltier heat exchanger test component and thermal energy water storage tank were measured during both cold and hot tank charging operations. The thermal efficiencies of the TE heat pump cooling/heating system are reported. The effects of the TE power input, number of TE units, rate of fluid flow, and heat sink/source temperature are studied.

scholarly journals Domestic Hot Water Storage Tank Utilizing Phase Change Materials (PCMs): Numerical Approach

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2170 ◽  
Author(s):  
Ayman Bayomy ◽  
Stephen Davies ◽  
Ziad Saghir
Keyword(s):  
Phase Change ◽  
Water Temperature ◽  
Storage Tank ◽  
Thermal Storage ◽  
Hot Water ◽  
Solar Thermal ◽  
Water Tank ◽  
Storage Efficiency ◽  
Domestic Hot Water ◽  
Water Storage Tank

Thermal energy storage (TES) is an essential part of a solar thermal/hot water system. It was shown that TES significantly enhances the efficiency and cost effectiveness of solar thermal systems by fulfilling the gap/mismatch between the solar radiation supply during the day and peak demand/load when sun is not available. In the present paper, a three-dimensional numerical model of a water-based thermal storage tank to provide domestic hot water demand is conducted. Phase change material (PCM) was used in the tank as a thermal storage medium and was connected to a photovoltaic thermal collector. The present paper shows the effectiveness of utilizing PCMs in a commercial 30-gallon domestic hot water tank used in buildings. The storage efficiency and the outlet water temperature were predicted to evaluate the storage system performance for different charging flow rates and different numbers of families demands. The results revealed that increases in the hot water supply coming from the solar collector caused increases in the outlet water temperature during the discharge period for one family demand. In such a case, it was observed that the storage efficiency was relatively low. Due to low demand (only one family), the PCMs were not completely crystallized at the end of the discharge period. The results showed that the increases in the family’s demand improve the thermal storage efficiency due to the increases in the portion of the energy that is recovered during the nighttime.

Experimental Evaluation of a Water Source CO2 Heat Pump Incorporating Novel Gas-Cooler Configuration

2014 ◽  
Author(s):  
Portia Murray ◽  
Stephen Harrison ◽  
Gary Johnson ◽  
Ben Stinson
Keyword(s):  
Heat Pump ◽  
Flow Rate ◽  
Storage Tank ◽  
Experimental Testing ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Convection Flow ◽  
Water Tank ◽  
Forced Circulation ◽  
Side Flow

Carbon dioxide’s use as an alternative refrigerant has been increasing in popularity due to its low global warming and ozone depletion potentials. In recent years, a number of companies and researchers have investigated applications of CO2 heat pumps for water heating. This study investigates the experimental testing of a CO2 heat pump water heater (HPWH) at Queen’s University. For the tests, the conventional factory gas-cooler on an Eco-cute unit and air-source evaporator was replaced with a specially designed brazed-plate gas-cooler. It rejected heat to a 273 litre hot water and the evaporator sourced heat from a warm water supply. Experiments were conducted using both forced and natural convection (i.e., thermosyphon) flow between the gas-cooler and hot water tank. Thermosyphon flow was studied to evaluate its effects on storage tank stratification and heat pump operation (i.e., coefficient of performance). Results were compared to forced circulation cases run over a range of flow rates. In the forced convection flow test, it was observed that a decrease in gas-cooler average water temperature increased the coefficient of performance (COP) non-linearly and an increase in the water-side flow rate increased the COP and the effectiveness of the gas-cooler. The thermosyphon had an average flow rate of 0.75 L/min and an average COP of 3.1. Thermosyphon flow kept the hot water tank fully stratified until fully charged. Water was delivered at an average of 70°C. It was also observed that thermosyphon flow rate depended on the state of charge (i.e., temperature distribution) in the storage tank. In order to increase the performance, a gas-cooler with a lower pressure drop should be used to increase the thermosyphon flow rate.

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