Performance Enhancement Study of R410A Direct Evaporation Ice-Storage System Using Divided Storage Tank

Author(s):  
Chen Xueqing ◽  
Chen Ying ◽  
Shi Yongkang
Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3878 ◽  
Author(s):  
Peter Sivák ◽  
Peter Tauš ◽  
Radim Rybár ◽  
Martin Beer ◽  
Zuzana Šimková ◽  
...  

The energy storage field is nowadays a highly ranking topic. This research deals with the installation and analysis of the ice storage system which combines heat pump, solar absorber, and ice storage tank (phase change material—PCM). This system uses a special kind of solar absorber – header pipes (HDP), which have no thermal isolation compared to the common solar absorber. Thanks to that the HDP, pipes can absorb thermal energy not only from the sun but also from the environment. The rain or snow also affects heat exchange. All that is provided by one technical device. The system can store thermal energy gained from the solar absorber into the ice storage tank for future usage. Research works with data from the real operation, for a period of the year covering all working phases/modes of the system. The analysis of the data led to the identification of several specific modes of the system, especially from the processes taking place in the PCM storage tank during its charging and discharging at various time stages of operation of the whole system. The installation and analysis of the ice storage system probably took place for the first time in Slovakia and Slovak Republic’s conditions. Besides, this system was not installed on a new low-energy house, but on an older family house with thermal insulation. The aim of this installation was also to demonstrate the usability of the ice storage system in an older house and potentially reduce the homeowner’s fees thanks to new technology with higher efficiency. We managed to comprehensively analyze and describe the operation of this system, which also appears to be highly efficient even in a family house with a lower energy certificate, than today’s new low-energy buildings. The results showed a significant efficiency difference in favor of the ice storage system compared to conventional heating systems. The total analysis time was 1616 h and the total efficiency of this heating system—the seasonal coefficient of performance (SCOP) was 4.4. Compared to the average SCOP 3.0 of conventional heating systems for new low-energy houses, the total efficiency increased by 46.6%. These results could therefore be considered as beneficial, especially if we take into account that this system was installed on an approximately 40-year-old family house. The analyzed ice storage system is still working today. The main goals of this paper were to describe the heat pump’s duty cycle with ice storage (PCM) based on real-life data and bring a detailed description of the heat transfer medium behavior at various phases of storing/utilizing heat in the vertical ice storage’s profile for increasing efficiency.


2013 ◽  
Vol 671-674 ◽  
pp. 2515-2519
Author(s):  
Xue Mei Wang ◽  
Zhen Hai Wang ◽  
Xing Long Wu

This project aims to study the optimal control model of the ice-storage system which is theoretically close to the optimal control and also applicable to actual engineering. Using Energy Plus, the energy consumption simulation software, and the simple solution method of optimal control, researchers can analyze and compare the annual operation costs of the ice-storage air-conditioning system of a project in Beijing under different control strategies. Researchers obtained the power rates of the air-conditioning system in the office building under the conditions of chiller-priority and optimal contro1 throughout the cooling season. Through analysis and comparison, they find that after the implementation of optimal control, the annually saved power bills mainly result from non-design conditions, especially in the transitional seasons.


Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan

With a large capacity thermal storage system using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency of solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF). While the dual-media sensible heat storage system has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study; particularly, the sizing of volumes of storage tanks considering actual operation conditions is of significance. In this paper, a strategy for LHSS volume sizing is proposed, which is based on computations using an enthalpy-based 1D model. One example of 60MW solar thermal power plant with 35% thermal efficiency is presented. In the study, potassium hydroxide (KOH) is adopted as PCM and Therminol VP-1 is used as HTF. The operational temperatures of the storage system are 390°C and 310°C, respectively for the high and low temperatures. The system is assumed to operate for 100 days with 6 hours charge and 6 hours discharge every day. From the study, the needed height of the thermal storage tank is calculated from using the strategy of tank sizing. The method for tank volume sizing is of significance to engineering application.


2014 ◽  
Vol 937 ◽  
pp. 375-380
Author(s):  
Yi Liu ◽  
Xin Chen

The numerical simulation of the ice melting processes in internal melt-ice-on-tube which is applied widely in the ice storage system is carried out. The dynamic mathematical models about melting are established and solved by using enthalpy method. Natural convection of the melted water in the course of melting is studied, and natural convection influences on single tube in melting heat transfer process is analyzed under the related parameters. Several conclusions are obtained:1. Because of natural convection of the melted water, the curve of melting interface is no longer a circle, but a curve changing with angle. The melting radius reaches minimum at the bottom and maximum at the top.2. The one with natural convention is compared to the other not considered. At initial stage, the influence of natural convection is smaller in the course of melting. However, the influence of natural convention increases along with melting.


Author(s):  
Inri Rodriguez ◽  
Jesus Cerda ◽  
Daniel S. Codd

A prototype water-glycerol two tank storage system was designed to simulate the fluidic properties of a high temperature molten salt system while allowing for room temperature testing of a low cost, small scale pneumatically pumped thermal storage system for use in concentrated solar power (CSP) applications. Pressurized air is metered into a primary heat transfer fluid (HTF) storage tank; the airflow displaces the HTF through a 3D printed prototype thermoplate receiver and into a secondary storage tank to be dispatched in order to drive a heat engine during peak demand times. A microcontroller was programmed to use pulse-width modulation (PWM) to regulate air flow via an air solenoid. At a constant frequency of 10Hz, it was found that the lowest pressure drops and the slowest flowrates across the receiver occurred at low duty cycles of 15% and 20% and low inlet air pressures of 124 and 207 kPa. However, the data also suggested the possibility of slug flow. Replacement equipment and design modifications are suggested for further analysis and high temperature experiments. Nevertheless, testing demonstrated the feasibility of pneumatic pumping for small systems.


2019 ◽  
Vol 108 ◽  
pp. 02013
Author(s):  
Piotr Babiński ◽  
Michalina Kotyczka – Morańska ◽  
Jarosław Zuwała

The paper presents the results of the fundamental research devoted to the application of MgSO4 as a heat carrier for thermochemical seasonal storage system devoted for household application followed by the results of 35kWh storage tank (TRL IV) charging and discharging tests. Seasonal thermochemical heat storage, based on the reversible reactions of hydratation and dehydratation of a solid medium gives an opportunity to accumulate the energy with a storage capacity exceeding 300-400 kWh/m3.


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