Characterization of an Air-PCM Energy Storage Design for Air Handling Unit Applications

2017 ◽  
Author(s):  
Sarah Wert ◽  
Cynthia A. Cruickshank ◽  
Dominic Groulx
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Testing Temperature ◽  
Storage Device ◽  
Flow Rates ◽  
Transfer Rates ◽  
Melting Temperatures ◽  
Air Handling Unit ◽  
Vertically Aligned

This paper will discuss the characterization of an air-PCM storage design for commercial air handling unit (AHU) applications during winter. The air-PCM storage design consists of two rows of 29 aluminum flat plate containers (0.45 m × 0.35 m × 0.01 m) filled with PCM, vertically aligned leaving an air channel between each plate of 0.011 m wide. The storage device was placed within a closed air loop which conditions the air to the desired testing temperature and velocity. The PCM selected for testing was RT44HC with a melting temperature of 44 °C. This PCM was chosen for its similar properties to other PCMs having lower melting temperatures (in the range of 5 to 18°C) that could be used in actual HVAC application implementation. The system was instrumented and calibrated with Type T thermocouples and a velocity sensor. The system was tested at various inlet temperatures (55°C to 63°C for charging and 12°C to 25°C for discharging) and flow rates. The instantaneous heat transfer rates and total energy storage were calculated for each test from the data collected. The results provide a baseline value for heat transfer rates in a simple air-PCM design, to be used for model validation.

scholarly journals Heat transfer enhancement of car radiator using aqua based magnesium oxide nanofluids

2015 ◽  
Vol 19 (6) ◽  
pp. 2039-2048 ◽  
Author(s):  
Hafiz Ali ◽  
Muhammad Azhar ◽  
Musab Saleem ◽  
Qazi Saeed ◽  
Ahmed Saieed
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Management ◽  
Heat Transfer Performance ◽  
Inlet Temperature ◽  
Fluid Temperature ◽  
Transfer Enhancement ◽  
Volumetric Concentration ◽  
Flow Rates ◽  
Transfer Rates

The focus of this research paper is on the application of water based MgO nanofluids for thermal management of a car radiator. Nanofluids of different volumetric concentrations (i.e. 0.06%, 0.09% and 0.12%) were prepared and then experimentally tested for their heat transfer performance in a car radiator. All concentrations showed enhancement in heat transfer compared to the pure base fluid. A peak heat transfer enhancement of 31% was obtained at 0.12 % volumetric concentration of MgO in basefluid. The fluid flow rate was kept in a range of 8-16 liter per minute. Lower flow rates resulted in greater heat transfer rates as compared to heat transfer rates at higher flow rates for the same volumetric concentration. Heat transfer rates were found weakly dependent on the inlet fluid temperature. An increase of 8?C in inlet temperature showed only a 6% increase in heat transfer rate.

Experimental Investigation on Enhancement of Heat Transfer in Thermal Energy Storage System Using Paraffin Wax as PCM

2015 ◽  
Vol 766-767 ◽  
pp. 457-462 ◽  
Author(s):  
N. Beemkumar ◽  
A. Karthikeyan
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Energy Storage System ◽  
Paraffin Wax ◽  
Maximum Heat ◽  
Transfer Rates ◽  
Thermal Energy Storage System

An experimental study is conducted to investigate heat transfer enhancement in Thermal Energy Storage system (TES) with paraffin wax as a Phase Change Material (PCM). Therminol 66 is used as a heat transfer fluid (HTF) to carry the heat throughout circuit. The PCM is encapsulated in spherical shells which is stored in the storage tank. The work includes study of heat transfer rates between HTF and PCM with different encapsulation materials namely Copper, Aluminium and Brass. A series of experiments were conducted to investigate the time required and heat transfer rates of HTF during the processes of charging and discharging of the PCM. Experimentally, Copper was found to have the maximum heat transfer rate and Brass was found to have the least cost/kW of energy stored. In discharging process, the cumulative heat gained by HTF from the brass encapsulated PCM is higher (1419.8 kJ) than aluminium (1199.96 kJ) and copper (815.24 kJ). Thus it can be concluded the brass is the most economical encapsulating material for enhancing the heat transfer in a thermal storage system than copper. The heat transfer from the HTF to PCM occurs in copper are 4.9% faster when compared to Brass and 2.3% faster than Aluminum encapsulation. On the other hand, The cost per kW energy transfer from the different encapsulated materials proves that the brass is cost effective during both charging and discharging process.

Heat Transfer in Vertically Aligned Phase Change Energy Storage Systems

1999 ◽  
Vol 121 (2) ◽  
pp. 98-109 ◽  
Author(s):  
H. T. El-Dessouky ◽  
W. S. Bouhamra ◽  
H. M. Ettouney ◽  
M. Akbar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Energy Storage ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Storage Systems ◽  
Flow Direction ◽  
Vertically Aligned ◽  
Bottom To Top

Convection effects on heat transfer are analyzed in low temperature and vertically aligned phase change energy storage systems. This is performed by detailed temperature measurements in the phase change material (PCM) in eighteen locations forming a grid of six radial and three axial positions. The system constitutes a double pipe configuration, where commercial grade paraffin wax is stored in the annular space between the two pipes and water flows inside the inner pipe. Vertical alignment of the system allowed for reverse of the flow direction of the heat transfer fluid (HTF), which is water. Therefore, the PCM is heated from the bottom for HTF flow from bottom to top and from the top as the HTF flow direction is reversed. For the former case, natural convection affects the melting process. Collected data are used to study variations in the transient temperature distribution at axial and radial positions as well as for the two-dimensional temperature field. The data is used to calculate the PCM heat transfer coefficient and to develop correlations for the melting Fourier number. Results indicate that the PCM heat transfer coefficient is higher for the case of PCM heating from bottom to top. Nusselt number correlations are developed as a function of Rayleigh, Stefan, and Fourier numbers for the HTF flow from bottom to top and as a function of Stefan and Fourier numbers for HTF flow from top to bottom. The enhancement ratio for heat transfer caused by natural convection increases and then levels off as the inlet temperature of the HTF is increased.

A Simplified Numerical Approach to Characterize the Thermal Response of a Moving Bed Solar Reactor

2021 ◽  
Author(s):  
Assaad Al Sahlani ◽  
Kelvin Randhir ◽  
Nesrin Ozalp ◽  
James Klausner
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Energy Storage ◽  
Solid Particle ◽  
Gas Flow ◽  
Plug Flow ◽  
Fixed Bed ◽  
Flow Rates ◽  
Proposed Model ◽  
Simulation Results

Abstract Concentrated solar thermochemical storage in the form of a zero-emission fuel is a promising option to produce long-duration energy storage. The production of solar fuel can occur within a cylindrical cavity chemical reactor that captures concentrated solar radiation from a solar field. A heat transfer model of a tubular plug-flow reactor is presented. Experimental data from a fixed bed tubular reactor are used for model comparison. The system consists of an externally heated tube with counter-current flowing gas and moving solid particles as the heated media. The proposed model simulates the dynamic behavior of temperature profiles of the tube wall, gas, and particles under various gas flow rates and residence times. The heat transfer between gas-wall, solid particle-wall, gas-solid particle, are numerically studied. The model is compared with experiments using a 4 kW furnace with a 150 mm heating zone surrounding a horizontal alumina tube (reactor) with 50.8 mm OD and a thickness of 3.175 mm. Solid fixed particles of magnesium manganese oxide (MgMn2O4) with the size of 1 mm are packed within the length of 250 mm at the center of the tube length. Simulation results are assessed with respect to fixed bed experimental data for four different gas flow rates, namely 5, 10, 15, 20 standard liters per minute of air, and furnace temperatures in the range of 200 to 1200 °C. The simulation results showed good agreement with maximum steady state error that is less than 6% of those obtained from the experiments among all runs. The proposed model can be implemented as a low-order physical model for the control of temperature inside plug-flow reactors for thermochemical energy storage (TCES) applications.

Experimental Characterization of Heat Transfer and Thermal Energy Storage Capability Using Swirling Two-Phase Flow in the Package Integrated Cyclone COoler (PICCO)

2020 ◽  
Author(s):  
Peter deBock ◽  
Rinaldo Miorini ◽  
Cathleen Hoel ◽  
Darin Sharar ◽  
Bryan Whalen
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Thermal Performance ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Two Phase ◽  
Thermal Capacitance

Abstract The increasing demand for high power density wide-bandgap power electronics has propelled heat transfer research leading to a constant increase in the thermal performance of cold plates and heat sinks. Most of this research has focused on reducing thermal resistance of the package which can have a detrimental effect on transient thermal performance if thermal capacitance is reduced. In order to provide both a low thermal resistance and a higher thermal capacitance integrated into the package and near the thermal junction, a new cold plate called the Package Integrated Cyclone COoler (PICCO) was developed. GE Research and the US Army Research Lab collaborated to explore and validate the potential of this concept. The PICCO coldplate, which is enabled by 3D printing, establishes a swirling coolant flow field to remove heat. The swirling flow is anticipated to significantly aid in vapor removal from the surface and hence allow for the fluid to provide thermal capacitance through two-phase heat transfer efficiently. This paper describes the experiment design and development for thermal storage and cooling performance characterization of PICCO. The test rig includes a high-pressure capability gear pump moving fluid first through a Coriolis flowmeter and then through PICCO, where the fluid is accelerated in the cyclone and heated by miniaturized ceramic heaters, simulating SiC power electronics. The coolant releases the accumulated enthalpy to a plate-fin heat exchanger that is connected to a chiller. Several absolute and differential pressure transducers and thermocouples monitor the state of FC-72. The experiments will provide empirical transfer functions characterizing the PICCO pressure drop, heat transfer coefficient, critical heat flux and thermal energy storage capability.

Energy and Exergy Analysis of Thermal Energy Storage Prototype by Using Concrete Material in Thailand

2016 ◽  
Vol 839 ◽  
pp. 14-22
Author(s):  
Rungrudee Boonsu ◽  
Sukruedee Sukchai
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Energy Storage ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Transfer Fluid ◽  
Saturated Steam ◽  
Fluid Temperature ◽  
Flow Rates

The research was performed on thermal energy storage prototype in Thailand. Concrete was used as the solid media sensible heat material in order to fulfill local material utilization which is easy to handle and low cost. Saturated steam was used for heat transfer fluid. The thermal energy storage prototype was composed of pipes embedded in a concrete storage block. The embedded pipes were used for transporting and distributing the heat transfer medium while sustaining the pressure. The heat exchanger was composed of 16 pipes with an inner diameter of 12 mm and wall thickness of 7 mm. They were distributed in a square arrangement of 4 by 4 pipes with a separation of 80 mm. The storage prototype had the dimensions of 0.5 x 0.5 x 4 m. The charging temperature was maintained at 180°C with the flow rates of 0.009, 0.0012 and 0.014 kg/s whereas the inlet temperature of the discharge was maintained at 110°C. The performance evaluation of a thermal energy storage prototype was investigated in the part of charging/discharging. The experiment found that the increase or decrease in storage temperature depends on the heat transfer fluid temperature, flow rates, and initial temperature. The energy efficiency of the thermal energy storage prototype at the flow rate of 0.012 kg/s was the best because it dramatically increased and gave 41% of energy efficiency in the first 45 minutes after which it continued to rise yet only gradually. Over 180 minutes of operation time, the energy efficiency at this flow rate was 53% and the exergy efficiency was 38%.

Characterization of Carbon Nanotube Forest Interfaces Using Time Domain Thermoreflectance

2015 ◽  
Author(s):  
Thomas L. Bougher ◽  
John H. Taphouse ◽  
Baratunde A. Cola
Keyword(s):  
Heat Transfer ◽  
Contact Resistance ◽  
Time Domain ◽  
Thermal Contact ◽  
Thermal Interface Materials ◽  
Length Scales ◽  
Aligned Carbon Nanotubes ◽  
Theoretical Predictions ◽  
Vertically Aligned

Forests comprised of nominally vertically aligned carbon nanotubes (CNTs) are excellent candidates for thermal interface materials (TIMs) due to their theoretically predicted outstanding thermal and mechanical properties. Unfortunately, due to challenges in the synthesis and characterization of these materials reports of the thermal conductivity and thermal contact resistance of CNT forests have varied widely and typically fallen far short of theoretical predictions. In particular, the micro- and nano-length scales characteristic of the heat transfer in CNT forests pose significant challenges and may lead to misreported results. Here we examine the ability of a popular and well-established thermal metrology technique, time-domain thermoreflectance (TDTR), to resolve the properties of CNT forest TIMs. The characteristic heating frequencies of TDTR (1–10 MHz) are used to probe heat transfer at length scales spanning ∼0.1–1 μm, applicable for measuring the contact resistance between the CNT forest free tips and an opposing substrate. We identify the range of CNT forest-opposing substrate interface resistances that can be resolved with TDTR, and simultaneously demonstrate the effectiveness of several processes developed to reduce the resistance of these interfaces. The limitations of characterizing CNT forests with TDTR are discussed in terms of uncertainty and sensitivity to parameters of interest.

Heat Transfer and Pumping on a Rotating Disk With Freely Induced and Forced Cooling

1970 ◽  
Vol 92 (3) ◽  
pp. 342-348 ◽  
Author(s):  
Darryl E. Metzger
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Rotating Disk ◽  
Turbine Rotor ◽  
Experimental Facility ◽  
Heat Transfer Characteristics ◽  
Flow Rates ◽  
Transfer Rates ◽  
Small Flow ◽  
Forced Cooling

An experimental study of the heat transfer characteristics of flows between a high speed rotating disk and a parallel stationary shroud is presented. Flow and disk heat transfer rates have been determined for various combinations and rates of freely induced and forced flows supplied at both the hub and rim of the disk. The study models a practically important class of turbine rotor cooling problems where small flow rates similar in magnitude to the disk pumping flows are of interest. The experimental facility and procedures are described in detail. They have been designed to facilitate rapid and economical acquisition of rotor cooling characteristics in situations where the particular rotor-shroud geometry makes existing correlations inadequate.

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