Experiment Study for Evaluation of Phase Change Material Cooling Vest’s Effectiveness at Two Melting Points Used by People With Paraplegia During Exercise

2020 ◽  
Author(s):  
Farah Mneimneh ◽  
Nesreen Ghaddar ◽  
Kamel Ghali ◽  
Charbel Moussalem ◽  
Ibrahim Omeis
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Core Temperature ◽  
Perceived Exertion ◽  
Ambient Conditions ◽  
Melting Points ◽  
Cord Injury ◽  
Change Material ◽  
Skin Temperatures

Abstract Phase change material (PCM) cooling vests were tested on people with thoracic (T1-T12) spinal cord injury (SCI), also called people with paraplegia (PA), during exercise in heat. The purpose was to reduce heat stress, limit the increase in core temperature, and improve thermal comfort for PA under high metabolic rates and hot ambient conditions. This health risk was a result of thoracic SCI and disruption of thermoregulatory responses in PA. The current study aims to evaluate the efficacy of cooling vest on PA during arm-crank exercise at two melting points, 20°C (V20) and 14°C (V14) compared to no vest test (NV). Eleven participants with high- (T1-T3) and mid-thoracic SCI (T4-T8) were selected to participate in three tests. Core and skin temperatures and heart rate values were measured during 15-min precondition, 30-min exercise and 15-min recovery. Subjective voting of thermal comfort, sensation, skin wettedness and perceived exertion were recorded during exercise only. The main findings revealed significant reduction in change in core temperature (0.42±0.3°C;0.38±0.2°C) in V20 and V14 compared to NV tests for mid-thoracic group. For high-thoracic group, V20 and V14 were least effective in reducing core temperature (p > 0.05). Improvements in thermal comfort was established when using V14 and V20 compared to NV by 85% and 30% for high-thoracic group and by 72% and 53% for mid-thoracic group.

A Comparative Study on the Effectiveness of Evaporative and Phase Change Material Cooling Vests for People With Paraplegia

2021 ◽  
Author(s):  
Farah Mneimneh ◽  
Nesreen Ghaddar ◽  
Kamel Ghali ◽  
Charbel Moussalem ◽  
Ibrahim Omeis
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Core Temperature ◽  
Perceived Exertion ◽  
Body Core Temperature ◽  
Light Weight ◽  
Ambient Conditions ◽  
Cord Injury ◽  
Body Core ◽  
Change Material

Abstract Personal cooling vests to alleviate thermal strain in persons with thoracic spinal cord injury (SCI), named paraplegia, were tested. Mainly, phase change material (PCM) cooling vests were the most frequent type applied at different exercises and ambient conditions. Published results of PCM cooling vests indicated its significant effect in reducing body core temperature for persons having more than 50% of their trunk skin as sensate. Nevertheless, preferences of persons with SCI obtained from subjective voting during experimental studies revealed that the use of PCM cooling vests caused additional burden weight on the body and sometimes restricted the movement. It is of interest to investigate the effect of an alternative personal evaporative cooling vest (ECV), characterized by light weight and practical use without hindering body movement of persons with SCI. In this study, it is aimed to compare the effect of ECV on the physiological and psychological responses of persons with SCI compared to that of PCM cooling vests under the same ambient conditions and metabolic rates. The research methodology included human subject experiments for persons with mid-thoracic (T4-T8) and low-thoracic (T9-T12) injury where the sensate skin of the trunk is at least 50% of its area. Thirteen participants were recruited to perform an arm-crank exercise at a constant load of 30 W for 30-min while using ECV inside a controlled climatic chamber of hot conditions (30°C, 4 0% RH). Measurements of body core and skin temperatures as well as thermal comfort and sensation, perceived exertion and skin wettedness were done. Furthermore, Multi-way ANOVA test was conducted to analyse the results of three tests: no vest (NV), with ECV, and with PCM. Findings of mid- and low-thoracic groups showed similar effectiveness of ECV compared to PCM cooling vest in reducing core temperature, yet the change in perceived exertion was better with the use of ECV due to its light weight.

scholarly journals Effect of Phase Change Material Cooling Vests on Body Thermoregulation and Thermal Comfort of Patients With Paraplegia: A Human Subject Experimental Study

2021 ◽  
pp. 219256822110491
Author(s):  
Charbel K. Moussalem ◽  
Farah Mneimneh ◽  
Rana Sarieddine ◽  
Shadi Bsat ◽  
Mohamad N. El Houshiemy ◽  
...  
Keyword(s):  
Experimental Study ◽  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Recovery Period ◽  
Thoracic Spinal Cord ◽  
Increased Risk ◽  
Cord Injury ◽  
Cooling Effects ◽  
Change Material

Study design Randomized experimental study. Objective Compared to able-bodied people, patients with paraplegia due to thoracic spinal cord injury (SCI) are at an increased risk of heat illnesses during exercise due to impaired thermoregulatory responses. To overcome this limitation, we investigated the performance of three phase change material (PCM) cooling vests of different melting temperatures (Eijsvogels, #49) and coverage area of the trunk. Methods Sixteen participants were divided into three groups according to their injury level. All were tested for V20 full vest (20°C Tm, 75% coverage). Mid-thoracic and high-thoracic groups were tested for V14 vest (14°C Tm, 75% coverage). The mid-thoracic group was tested for V20 half vest (20°C Tm, 50% coverage). The participants performed a 30-min arm-crank exercise followed by a recovery period inside a controlled hot climatic chamber. The heart rate, segmental skin (Tskin), and core temperature (Tcore) values were recorded, and subjective questionnaires were taken. Results Compared to no vest (NV) test, all the vests showed an effective decrease in Tskin values of the trunk. However, the decrease in Tskin was not enough to induce a significant decrease in Tcore in all three groups. Mid-thoracic and low-thoracic groups showed a reduction in the increasing Tcore by the end of the exercise and recovery period. Finally, the level of thermal comfort was enhanced for the three groups. Conclusion The effectiveness of cooling vests for persons with paraplegia is dependent on injury level and thus the ratio of sensate to insensate skin. Future studies necessitate the investigation of the cooling effects of PCM vests at a lower Tm with a larger sample size.

scholarly journals Effect of phase change material using in building thermal comfort applications through several climate conditions.

2020 ◽  
Vol 170 ◽  
pp. 01007
Author(s):  
Marwa El Yassi ◽  
Ikram El Abbassi ◽  
Alexandre Pierre ◽  
Yannick Melinge
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Chemical Change ◽  
Thermal Inertia ◽  
Temperature Fluctuations ◽  
High Energy ◽  
Climate Conditions ◽  
Change Material

Nowadays, buildings sector contributes to climate change by consuming a considerable amount of energy to afford thermal comfort for occupants. Passive cooling techniques are a promising solution to increase the thermal inertia of building envelopes, and reduce temperature fluctuations. The phase change materials, known as PCM, can be efficiently employed to this purpose, because of their high energy storage density. Among the various existing solutions, the present study is dedicated to solid-liquid phase change materials. Temperature evolution (according to their defined temperature range) induces the chemical change of the material and its state. For building applications, the chemical transition can be accomplished from liquid to solid (solidification) and from solid to liquid (melting). In fact, this paper presents a comparative thermal analysis of several test rooms with and without phase change materials embedded in a composite wallboard in different climates. The used PCM consist in a flexible sheet of 5 mm thickness (Energain, manufactured by the company DuPont de Nemours). The main properties of such a commercial solution have been delivered by the manufacturer and from analyses. The room model was validated using laboratory instrumentations and measurements of a test room in four cities: Lyon; Reading and Casablanca. Results indicate that this phase change material board can absorb heat gains and also reduce the indoor air temperature fluctuations during daytime. The aim of the study is to show the benefits of this layer with phase change material and compare it in different climatic zones.

Red-mud geopolymer composite encapsulated phase change material for thermal comfort in built-sector

Solar Energy ◽  
2019 ◽  
Vol 181 ◽  
pp. 464-474 ◽  
Author(s):  
Lukmon Owolabi Afolabi ◽  
Zulkifli Mohamad Ariff ◽  
Puteri Sri Melor Megat-Yusoff ◽  
Hussain H. Al-Kayiem ◽  
Adiat Ibironke Arogundade ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Red Mud ◽  
Encapsulated Phase Change Material ◽  
Change Material

Increasing Energy Efficiency of HVAC Systems of Buildings Using Phase Change Material

2011 ◽  
Author(s):  
Lee Chusak ◽  
Jared Daiber ◽  
Ramesh Agarwal
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Energy Requirements ◽  
Exterior Wall ◽  
Displacement Ventilation ◽  
Cooling Systems ◽  
Comfort Levels ◽  
Chilled Ceiling ◽  
Change Material

Using Computational Fluid Dynamics (CFD), four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare arrangements for (a) an all-air overhead system (mixing ventilation), (b) a combined air and hydronic radiant system (overhead system with a chilled ceiling), (c) an all-air raised floor system (displacement ventilation), and (d) a combined air and hydronic radiant system (displacement ventilation with a chilled ceiling). The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall to compare the four cooling systems. The second set of computations consider a glass window, a phase change material layer and the plastic shade configuration for the exterior wall to examine the effect of the phase change material (PCM) layer on the cooling energy requirements. Both sets of simulations assumed an external wall that changed temperature as a function of time simulating the temperature changes on the exterior wall of the room during a 24 hour period. Results show superior thermal comfort levels as well as substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.

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