Modelling of Wearable Cooling SystemPROJECT SUMMARYThe idea to model a wearable thermal control system has been conducted by researchers on late of20th century. Although these studies still just being a proof of concept, advances were developed inawayproduceauseful product. ReleasedbyDhamannovations!vt. thefirst useful thermalcontrolclothdriventofinal costumer,isbasedonathermoelectriceffect toremoveheatfromhumanbody. Althoughmost researchershavefocusedonusingthermoelectriceffect, but nowdriven to not only heat removal but also including heat harvesting "#o $ung%&un et al. 20'2(.Thefocus and motivation of thisprojectisgatheralladvances made inthermalcontrolsystem andpropose an application for a use on a scenario. Although the human body has several mechanisms for thermoregulation, vasoconstriction,sweating, etc., the need to maintain its internal temperature around )* + , causes thermal stress forindividuals living with or e-posed daily to hot environments such as firefighters. As .uoted by /en!arson "20'2( despite all forms of self%internal temperature control the human body is e-tremelydependent on e-ternal conditions, one of the advances of humanity against these factors is the useof clothing in relation to other animals. Thus the first step was to model the mechanisms of heat andas the human body interacts with the environment. During the evaluation of models and surveyvariables came to math e.uation described below0MW=Qsk+Qres=(C+R+Esk)+(Cres+Eres)"'(where all terms have units of watts per s.uare metre and1 2 rate of metabolic energy production3 2 rate of mechanical wor45s4 2 total rate of heat loss from the s4in5res 2 total rate of heat loss through respiration, 2 rate of convective heat loss from the s4inR 2 rate of radiative heat loss from the s4in&s4 2 rate of total evaporative heat loss from the s4in,res 2 rate of convective heat loss from respiration&res 2 rate of evaporative heat loss from respirationn a way to simplify all calculation of heat transfer, was assumed steady state condition and themodel of heat transfer was adopted as presented on /en !arsons 20'2, a threelayered cylindricalmodel. 6sing the e.uation "'( was calculated the amount of heat generate by the core and loss toenvironment. As all results are strongly depend of environmental factors such as amount of solarradiation, wind, humidity and mechanical wor4. 7or the condition adopted, was found an amount ofaround )00%)80 3 of heat re.uired to be removed on a way to granted thermal comfort.To remove the heat from the body many cooling cycles were evaluated0 absorption, adsorption,9rayton and vapour compressed cycles. After comparison was decided to choose a vapourcompressed cycle once it has a relativity simple thermodynamic system and can be driven by avariety of power sources "Reinhard Radermacher 2008(, also on simulation it showed be able toremove the amount of heat desired.The concept of the wearable system can be shown below, 7igure '. The idea is cover the chest witha wearable garment vest with thermal insulation providing condition for a use of fle-ible tube tobuildawearableevaporator. !ower sources andcondenser wereconcept tobemountedonabac4pac4 configuration. The thermodynamic cycle is represented on 7igure '.Figure ! Con"e#tual $earable "ooling system%At this moment the research has found some set bac4 as is need perform some e-perimental test todetermine the amount of power re.uired and decide for power sources. These still going to be themost crucial factor and a limitation of amount use for this technology, although some progress hasbeen made in built high density batteries witch could be a future solution for this problem.REFERE&CES&rnst T. ,., :Design, 7abrication And Testing ;f A 3earable ,ooling $ystem 7ebruary 2008/en !arsons, :?uman Thermal &nvironments The &ffects ;f ?ot, 1oderate, And ,old&nvironments ;n ?uman ?ealth, ,omfort, And !erformance