Power Characteristics of a Continuous Crystallization Latent Heat Recovery System

1979 ◽  
Author(s):  
J. Hallett ◽  
G. Keyser
Keyword(s):  
Latent Heat ◽  
Heat Recovery ◽  
Sodium Acetate ◽  
Heat Storage ◽  
Sodium Thiosulfate ◽  
Power Characteristics ◽  
Continuous Crystallization ◽  
Recovery System ◽  
Continuous Generation ◽  
Salt Hydrates

A system for low quality heat storage through the latent heat of salt hydrates has been devised which gives only a slowly varying power output. This utilizes continuous generation and sedimentation of crystals. Heat transfer is accomplished by buoyant kerosene drops rising through a salt solution with concentration and size of suspended crystals controlled primarily by kerosene flow rate. The system has been investigated for sodium sulfate, sodium thiosulfate, and sodium acetate at working temperatures of 33, 48, 58 C, respectively. The sodium acetate system showed most promise and was studied quantitatively in a pilot unit.

Design and Performance of a Fuel Cell Plant Heat Recovery System

2007 ◽  
Author(s):  
Robert G. Ryan ◽  
Tom Brown
Keyword(s):  
Fuel Cell ◽  
Latent Heat ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

scholarly journals Analysis of Heat Transfer and Natural Convective of a Phase Change Material

2021 ◽  
Vol 9 (VII) ◽  
pp. 3028-3037
Author(s):  
T. Ravi Kumar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Heat Storage ◽  
Storage Device ◽  
Latent Heat Storage ◽  
Recovery System ◽  
Solid Liquid ◽  
Change Material

A phase-change material (PCM) is a substance with a high latent heat storage capacity which on melting and solidifying at a certain temperature, is capable of storing and releasing large amounts of energy. Various PCM like Paraffin wax, stearic acid are considered which are used to absorb heat from the coolant water from the engine. The conduction and convection criterion of heat transfer enable the PCM to store this heat as latent heat. The amount of convection and temperature change brought about due to the heat flux has been simulated and studied in detail using FLUENT. The thermal energy storage device (TESD) works on the effect of absorption and rejection of heat during the solid-liquid phase change of heat storage material. The overall function of the TESS is dominated by the PCM. The PCM material should be selected considering the application and the working conditions. Depending on the applications, the PCMs should first be selected based on their melting temperature for heat recovery system.

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