Development of a Cooling Garment With Encapsulated PCM

2000 ◽  
Author(s):  
David P. Colvin ◽  
Virginia S. Colvin ◽  
Yvonne G. Bryant ◽  
Linda G. Hayes ◽  
Michael A. Spieker
Keyword(s):  
Heat Stress ◽  
Phase Change ◽  
Protective Clothing ◽  
Environmental Control ◽  
Packed Bed ◽  
High Heat ◽  
Industrial Workers ◽  
Latent Heat Storage ◽  
Innovation Research ◽  
Cooling Garment

Abstract Under SBIR (Small Business Innovation Research) programs from the U.S. Marine Corps, investigators at Triangle Research and Development Corporation (TRDC) have conducted research toward the development of a unique passive cooling garment to provide significant microclimate cooling to Marines dressed in NBC (Nuclear/Biological/Chemical) protective clothing. The patented PECS (Protective Environmental Control System) garment utilizes 3–4 mm diameter macroencapsulated phase change material (macroPCM) particles distributed throughout a lightweight and highly breathable vest garment to provide 1–3 hours of cooling in high heat stress environments. With polymer walls encapsulating the paraffin PCM, the macroPCMs provide a wearable, packed bed heat exchanger that is flexible, highly breathable, and undergoes its solid/liquid phase change from 25–28°C, where its high latent heat storage can reach 60 calories/gram. This cooling range is at elevated and more comfortable temperatures than gel media used in other passive microclimate garments, which store their cold near 0°C and can cause shivering and discomfort. Although other microclimate garments require refrigeration or freezers to thermally recharge the cooling media, the passive 5-lb PECS cooling garment can be thermally recharged in the field at room temperatures (15–20°C) without refrigeration. Although earlier publications described the principles for such a cooling garment, this publication is the first to describe the garment’s construction, development and testing. Extensive laboratory testing has included Marine volunteers on a treadmill in a heated environmental chamber while dressed in Level IV MOPP and Level A protective clothing and a gas mask. PECS has also been used by costumed characters at Walt Disney World to provide extended cooling within an extended heat stress environment. Besides military uses, passive macroPCM garments should find other applications; including: protective clothing for firefighters, industrial workers, costumed characters and persons with heat stress disabilities.

Body Heat Stress Measurements With MacroPCM Cooling Apparel

2002 ◽  
Author(s):  
David P. Colvin
Keyword(s):  
Heat Stress ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
Environmental Control ◽  
Industrial Workers ◽  
Development Corporation ◽  
Chemical Protective Clothing ◽  
Hot Environments ◽  
Cooling Garments ◽  
Body Heat

Heat stress is a major problem for people who work or fight in hot environments while dressed in insulated or protective apparel. Such is the case for military personnel who must wear nuclear/biological/chemical (NBC) protective clothing or HAZMAT personnel as well as civilian personnel such as industrial workers, firemen, and costumed characters in amusement or theme parks. Responding to a request in 1991 by the NAVY to develop simple and lightweight cooling garments for use beneath NBC (nuclear/biological/chemical) protective clothing, the investigators at Triangle Research and Development Corporation (TRDC) have developed PECS (Personal Environmental Control System) and COOLTECH apparel, that utilizes 3–4mm diameter macro-encapsulated phase change materials or MacroPCMs to provide 1–2 hours of comfort and relief from heat stress, while permitting the garment’s thermal recharging without refrigeration or freezers.

Phase Change Material Freezing in an Energy Storage Module for a Micro Environmental Control System

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
H. Ezzat Khalifa ◽  
Mustafa Koz
Keyword(s):  
Mathematical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Environmental Control ◽  
Finite Thickness ◽  
Element Model ◽  
Storage Device ◽  
Freezing Process ◽  
Latent Heat Storage ◽  
Change Material

Abstract This study analyzes phase change material (PCM) freezing process in a novel latent heat storage device (LHSD). Heat is removed from the PCM with an embedded evaporator. A mathematical model of freezing in a finite-thickness PCM slab is presented. An experimentally validated reduced-order model (ROM) based on the mathematical model was developed to analyze the heat transfer between the freezing PCM and an evaporating refrigerant flowing inside a flat, microchannel tube coil embedded in the PCM. A detailed finite element model (FEM) of the same device was also developed and employed to verify the validity of the ROM over a wider range of conditions. The freezing times and total “cooling” stored in the PCM computed by the ROM agree very well with those computed by the detailed FEM. The ROM executes in ∼1 min for a full heat exchanger, compared with more than 10 h for the FEM, making the former much more practical for use in parametric analysis and optimization of design alternatives.

scholarly journals A Meta Study of the Relationship Between Phase Change Material Parameters and Temperature Reduction in Fire Fighter Protective Clothing

2019 ◽  
Vol 6 ◽  
pp. 28-37
Author(s):  
Josef Richmond ◽  
Lesley Spencer ◽  
Tommy Tran ◽  
Evan Williams
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
High Heat ◽  
Heat Fluxes ◽  
Fire Fighter ◽  
High Flux ◽  
Temperature Reduction ◽  
Change Material

Firefighters are exposed to high risk scenarios in which the prevention of extreme heat injuries is largely dependent on the effectiveness of their protective clothing. The following meta-study examines contemporary literature to determine the usefulness of phase change materials (PCM’s) in improving the effectiveness of the current firefighter protective clothing (FFPC) model in order to better protect firefighters. The time- temperature for multiple PCM’s in environments with low, medium and high heat fluxes (taken as 2.5-5 kW/m2 for 700 seconds, 10-15 kW/m2 for 300 seconds and 20-40 kW/m2for 30 seconds respectively) were compared in terms of the rate of temperature increase and final temperature. The study found that PCM I produced the best temperature reduction in a low flux, PCM K did so in a medium flux, and PCM B did so in a high flux. The study also found that overall the PCMs were most effective in a low flux, therefore further study should be directed towards creating PCMs that are more effective in high-flux environments. Keywords: Phase Change Material; Fire Fighter Protective Clothing; Heat Flux

A Cooling Vest for Construction Workers

2014 ◽  
Vol 1061-1062 ◽  
pp. 728-732
Author(s):  
Min Wu ◽  
Joe Dong ◽  
Andy Zhao ◽  
Wai Ching Tang ◽  
Willy Sher ◽  
...  
Keyword(s):  
Heat Stress ◽  
Body Temperature ◽  
Phase Change ◽  
Phase Change Material ◽  
Construction Workers ◽  
Cooling Garment ◽  
Change Material

Construction workers are vulnerable to heat stress, and a number of heat-related injuries and deaths have been reported. This study thus introduces a phase change material (PCM) based cooling garment designed for construction workers. The PCM cooling garment will be effective in reducing the workers body temperature and can extend their maximum tolerable time on sites.

Latent Heat Storage Plaster: Lab-Scale Experiment and Simulation

2014 ◽  
Vol 1077 ◽  
pp. 124-128
Author(s):  
Milan Ostrý ◽  
Pavel Charvát ◽  
Tomáš Klubal ◽  
Lubomír Klimeš
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
High Heat ◽  
Latent Heat Storage ◽  
Heating And Cooling ◽  
Scale Experiment ◽  
Building Operation

Energy storage can even out mismatches between the demand and supply of energy, thereby improving the system performance and reducing the cost of building operation. The energy storage is a key issue in the wider use of renewable energy. The experiments carried out at Brno University of Technology focus on the latent heat storage techniques for application in radiant heating and cooling of residential and office buildings. The latent heat storage techniques utilize Phase Change Materials (PCMs) as a heat storage medium and thus allow for the reduction of the amount of heat storage material due to the high heat storage density per volume or weight. In the past, much attention was paid to encapsulation of PCMs. The PCMs undergo phase change from solid to liquid and vice versa during a heat storage cycle and there is a risk of leakage of the PCMs to the building material or indoor environment. The microencapsulated organic PCMs in a mixture with gypsum plaster were used in the investigations described in this paper. The investigations involved both lab-scale experiments and numerical simulations.

Enhanced Thermal Management Using Encapsulated Phase Change Materials: An Overview

1999 ◽  
Author(s):  
David P. Colvin
Keyword(s):  
Research And Development ◽  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
High Heat ◽  
Advanced Technology ◽  
Business Innovation ◽  
Innovation Research ◽  
Thermal Capacitance ◽  
Agricultural Applications

Abstract Since 1983, investigators at Triangle Research and Development Corporation have pioneered the research and development of encapsulated phase change materials through 25 Small Business Innovation Research (SBIR) programs for NASA, DOD (USAF, NAVY, USMC, SDIO and SOCOM), NSF, USDA and HHS (NIOSH). Additional programs by licensees have also shown how these novel particles can produce superior apparel and coolant products. For pumped systems, two-component coolant slurries have demonstrated up to 40X (4,000%) improvement in the fluid’s effective thermal capacitance with up to 3X (300%) increase in the Nusselt Number within isothermal coolant loops for NASA, USAF and NAVY. MicroPCM machining coolants have also demonstrated enhanced heat transport along with significant reductions in tool wear, thermal distortions and coolant emissions for NSF and NIOSH. For un-pumped passive systems, microPCM powders have been added to textile fibers, and apparel foams for 10X enhancement in thermal storage. MicroPCM coatings are being developed for numerous agricultural applications for NSF and the USDA. PCMs are also being macroencapsulated for garments in high heat stress applications with the USMC. Numerous products are now being introduced to global markets using this advanced technology. This paper will address the above applications in an overview that will also provide an introduction to the other papers in this session.

Selection of Phase Change Materials for Latent Heat Storage

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
J. Martínez-Gómez ◽  
E. Urresta ◽  
D. Gaona ◽  
G. Guerrón
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Latent Heat Storage ◽  
Toma De Decisiones ◽  
Selection Of

Esta investigación tiene como objetivo seleccionar un material de cambio de fase (PCM) que cumplen mejor la solución del almacenamiento de energía térmica entre 200-400 ° C y reducir el costo de producción. El uso de métodos multicriterios de toma de decisiones (MCMD) para la evaluación fueron proporcionales implementados como COPRAS-G, TOPSIS y VIKOR. La ponderación de los criterios se realizó por el método AHP (proceso analítico jerárquico) y los métodos de entropía. La correlación de los resultados entre los tres métodos de clasificación ha sido desarrollada por el coeficiente de correlación de Spearman. Los resultados ilustran el mejor y la segundo mejor opción para los tres MCDM fueron NaOH y KNO3. Además, tenía valores de correlación de Spearman entre los métodos excede de 0.714.

Experimental Study on Thermal Characteristics of Finned Coil LHSU Using Paraffin as Phase Change Material

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Guansheng Chen ◽  
Nanshuo Li ◽  
Huanhuan Xiang ◽  
Fan Li
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Phase Change ◽  
Phase Change Material ◽  
Water Flow ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Heat Transfer Fluid ◽  
Latent Heat Storage ◽  
Change Material

It is well known that attaching fins on the tubes surfaces can enhance the heat transfer into and out from the phase change materials (PCMs). This paper presents the results of an experimental study on the thermal characteristics of finned coil latent heat storage unit (LHSU) using paraffin as the phase change material (PCM). The paraffin LHSU is a rectangular cube consists of continuous horizontal multibended tubes attached vertical fins at the pitches of 2.5, 5.0, and 7.5 mm that creates the heat transfer surface. The shell side along with the space around the tubes and fins is filled with the material RT54 allocated to store energy of water, which flows inside the tubes as heat transfer fluid (HTF). The measurement is carried out under four different water flow rates: 1.01, 1.30, 1.50, and 1.70 L/min in the charging and discharging process, respectively. The temperature of paraffin and water, charging and discharging wattage, and heat transfer coefficient are plotted in relation to the working time and water flow rate.

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