A Study of the Use of Heat Pipes in Thermal Storage for Cooling

2005 ◽  
Author(s):  
Franc¸ois Tardy ◽  
Samuel Sami
Keyword(s):  
Heat Exchange ◽  
Cold Storage ◽  
Storage Tank ◽  
Heat Pipes ◽  
Thermal Storage ◽  
Vapor Compression ◽  
Popular Method ◽  
Vapor Compression System ◽  
Cooling Loads ◽  
Change Material

Thermal storage is a popular method of shifting cooling loads to off-peak regions. A new method of discharge is proposed via use of a group of heat pipes inserted in a cold storage tank filled with ice, initially frozen by a separate vapor-compression system. The latent heat of the ice assures circulation in the pipes and heat exchange between warm air and the tank for several hours at a time. An experiment has been conducted by using mixtures of ice and water as phase change material inside the tank. The system is exposed to inlet air at various states of temperature, humidity and varying velocity. The system provides cooling for over 8 hours, and correlations of the system are discussed.

Volume Sizing for Thermal Storage With Phase Change Material for Concentrated Solar Power Plant

2014 ◽  
Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan
Keyword(s):  
Power Plant ◽  
Phase Change ◽  
Phase Change Material ◽  
Storage Tank ◽  
Solar Power ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Concentrated Solar Power ◽  
Change Material

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.

scholarly journals An experimental investigation of cold storage in an encapsulated thermal storage tank

2000 ◽  
Vol 23 (3-4) ◽  
pp. 133-144 ◽  
Author(s):  
Sih-Li Chen ◽  
Chin-Lung Chen ◽  
Chun-Chuh Tin ◽  
Tzong-Shing Lee ◽  
Ming-Chun Ke
Keyword(s):  
Experimental Investigation ◽  
Cold Storage ◽  
Storage Tank ◽  
Thermal Storage

scholarly journals Design and Performance Analysis of a Biodiesel Engine Driven Refrigeration System for Vaccine Storage

2013 ◽  
Vol 2 (2) ◽  
pp. 117-124
Author(s):  
K Kamsuk ◽  
D Damrongsak ◽  
N Tippayawong
Keyword(s):  
Engine Speed ◽  
Direct Injection ◽  
Primary Energy ◽  
Modular System ◽  
Speed Ratio ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Vapor Compression System ◽  
And Performance ◽  
Cooling Loads

A compact, stand-alone, refrigeration module powered by a small biodiesel engine for vaccine storage in rural use was proposed. The engine was of single cylinder, four-stroke, direct injection with displacement of 0.296 cm3 and compression ratio of 20:1. The refrigeration system was modified from an automotive vapor compression system. The system performance was analytically investigated. From the simulation, it was found to have acceptable operation over a range of speeds and loads. Performance of the system in terms of fuel consumption and torque tended to decrease with an increase in engine speed. The modular system was able to operate at cooling loads above 4.6 kW, with proper speed ratio between the engine and the compressor. Overall, primary energy ratio of the refrigeration was found to be maximum at 0.54.

scholarly journals Effect of Phase Change Material Storage on the Dynamic Performance of a Direct Vapor Generation Solar Organic Rankine Cycle System

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5904
Author(s):  
Jahan Zeb Alvi ◽  
Yongqiang Feng ◽  
Qian Wang ◽  
Muhammad Imran ◽  
Lehar Asip Khan ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Storage Tank ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Thermal Storage ◽  
Working Fluid ◽  
Vapor Generation ◽  
Cycle System ◽  
Change Material

Solar energy is a potential source for a thermal power generation system. A direct vapor generation solar organic Rankine cycle system using phase change material storage was analyzed in the present study. The overall system consisted of an arrangement of evacuated flat plate collectors, a phase-change-material-based thermal storage tank, a turbine, a water-cooled condenser, and an organic fluid pump. The MATLAB programming environment was used to develop the thermodynamic model of the whole system. The thermal storage tank was modeled using the finite difference method and the results were validated against experimental work carried out in the past. The hourly weather data of Karachi, Pakistan, was used to carry out the dynamic simulation of the system on a weekly, monthly, and annual basis. The impact of phase change material storage on the enhancement of the overall system performance during the charging and discharging modes was also evaluated. The annual organic Rankine cycle efficiency, system efficiency, and net power output were observed to be 12.16%, 9.38%, and 26.8 kW, respectively. The spring and autumn seasons showed better performance of the phase change material storage system compared to the summer and winter seasons. The rise in working fluid temperature, the fall in phase change material temperature, and the amount of heat stored by the thermal storage were found to be at a maximum in September, while their values became a minimum in February.

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.

Simulation of an Air-Cooled Solar-Assisted Absorption Air Conditioning System

2001 ◽  
Author(s):  
L. H. Alva Solari ◽  
J. E. González
Keyword(s):  
Storage Tank ◽  
Air Conditioning ◽  
Lithium Bromide ◽  
Thermal Storage ◽  
Ambient Air ◽  
Absorption System ◽  
Air Conditioning System ◽  
Component Design ◽  
Dynamic Cooling ◽  
Cooling Loads

Abstract This paper investigates the technical feasibility of using a compact, air-cooled, solar-assisted, absorption air conditioning system in Puerto Rico and similar regions. Computer simulations were conducted to evaluate the system’s performance when subjected to dynamic cooling loads. Within the computer model, heat and mass balances are conducted on each component of the system, including the solar collectors, thermal storage tank, the air-cooled condenser, and the air-cooled absorber. Guidance on component design and insight into the effects of such operating factors as ambient air temperature were gained from exercising the simulation model. Comparisons are made with an absorption air conditioning system that uses a cooling tower instead of air-cooled components. The particular absorption system of study is one that uses lithium bromide and water as the absorbent and refrigerant, respectively. The heat input to the absorption system generator is provided by an array of flat plate collectors that are coupled to a thermal storage tank. Systems having nominal cooling capacities of 10.5, 14, and 17.5 kW were considered. Useful information about the number of collectors needed, storage tank volume and efficiency of the overall system is presented.

scholarly journals Dynamic numerical study on phase change thermal storage heat transfer

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4171-4179
Author(s):  
Jie Cui ◽  
Guofeng Wang ◽  
Zhitang Guo ◽  
Shuo Yang ◽  
Honggang Pan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Storage ◽  
Thermal Storage ◽  
Transfer Effect ◽  
Fin Spacing ◽  
Change Material

Targeted at the poor heat transfer effect of the phase change thermal storage heat exchanger due to the low thermal conductivity of the phase change material, a fin-tube type phase change thermal storage heat exchanger has been proposed in the study. A 2-D model of the phase-change heat storage unit was established, and the dynamic heat transfer law of the melting and solidification of the phase change material, and the influence of the fin structure size on the heat storage/release performance of the heat exchanger were numerically analyzed. The results show that in the area close to the tube wall, the smaller the fin spacing, the larger the thickness, the faster the phase change heat storage/release speed, and the better heat transfer effect. In the central area of the phase change material, the greater the fin spacing and thickness, and the better the heat transfer effect of the phase change heat storage/release. The area close to the outer wall has the smallest temperature change, and the heat storage/release effect is the worst. Therefore, the use of energy storage heat exchangers with gradual fin thickness and spacing is an effective method to improve the heat transfer efficiency of existing equipment. In addition, in order to improve the heat exchange effect of the edge area of the phase change, its structure could be changed or the heat exchange form can be increased.

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