Webinar: System Level Thermal Solutions for Military Grade Technologies
hello everybody and welcome to advanced cooling technology's november webinar we'll be covering system-level thermal solutions for military-grade technologies. Our speakers today are Matt Keller and Devin Pelicone. Matt is the general manager of our york Pennsylvania location where he oversees design production and service operations armed with over 17 years of engineering experience. Matt provides invaluable expertise in ensuring ACT's customers get the best thermal solutions and technical service possible. Devin is the lead engineer of ACT's industrial products group at our Lancaster Pennsylvania location. he has over 10 years of experience designing and building both passive and active two-phase cooling systems for a wide range of applications including high performance computing and power electronics cooling before we get started i want to let everyone know that there will be a live question and answer portion at the conclusion of today's presentation if you have any questions feel free to submit them through the present throughout the presentation by using the question function on the dashboard matt and devin will be will be answering as many as time allows we'll follow up with an email for anyone whose questions are not answered live with all that said i'll turn things over to our speakers thanks kevin good afternoon everyone thank you for joining our webinar today tell you a little bit about advanced cooling technologies we are a thermal management company located in lancaster pennsylvania as our headquarters and we also have a branch in york pennsylvania we were founded in 2003 and we now have over 200 employees at both locations we have approximately 140 000 square feet of facility space and growing every year and we have an iso 9001 and as9100 quality management system we've won a number of awards through the military and aerospace product innovation awards for the different technologies we've developed over the years we also work exclusively work extensively in the small business innovation research grant so we won a number of tibbetts awards for that work and we have numerous patents and scientific publications related to thermal management technologies today we're going to be talking to you about some of our system level cooling technologies particularly environmental control units or ecu's glycol coolers and chillers some of our pump toothpaste or ptp cooling systems as well as phase change materials pcm and we'll end with a little bit of discussion about some of our electronic systems system controls um and packaging capabilities and then a little bit more about our testing and extra capabilities at the end and like kevin mentioned we'll be ending with some question and answer session to answer any questions you may have i'll turn it over to matt keller to start things off thanks devin when we talk about system level thermal solutions we're referring to equipment and accessories utilized to reject the heat generator by system components to the exterior environment that's usually the ambient condition ambient design conditions can be anywhere from negative 50 to 140 fahrenheit and zero to ten thousand feet elevations for terrestrial systems in some cases there may be a chill water infrastructure which would be the exterior environment we reject would reject heat too for example shipboard chill water or a facility chill water system so the first thing we need to understand is the design criteria what are the heat sources electronics are going to be a big one in pretty much every system these days and they're going to be sensible heat that may be a very continuous load or it could be transient in the case of directed energy systems occupants may be present in the system and they provide both sensible and latent heat loads that need to be addressed the envelope of the system allows conduction from outside temperatures to inside as well as additional thermal loads that come through due to solar radiation on the exterior skin of a system outdoor air may also be a load in the system if we're going to be providing fresh air for pressurization and making sure any leaks in the system leak out as well as ventilation for the occupants once we know what the loads in the system are we also have to understand what we're trying to maintain in the system so what's what are the acceptable conditions for electronics that's usually an entering air temperature to the electronics um with occupants it's more of a average space temperature that's being controlled um 60 to 80 degrees fahrenheit is kind of a reasonable range for that relative humidity below 60 is also usually required traditionally we don't get into adding humidity because of the logistical issues of providing a water source and maintaining a water source to keep the humidity levels up so one of the solutions we offer are environmental control units an ecu as we call them is basically an air conditioner built for military environments they provide conditioned air to an enclosed space uh they can be mounted uh to hard wall shelters or connected to soft wall shelters or hard wall shelters uh via flex flexible ducts so you see some photos here um there's a five ton ecu on the back of a trailer um behind a humvee uh we've got systems that are in the middle um that's again a five time possibly an aid time hooked up to a software shelter um there's a radar hub cooling unit in the upper right as well as a dual vertical system that's hard mounted to a hard wall shelter design considerations for ecu's um actually okay uh additionally ecu's are a good way to introduce outdoor air to a system that out to air can be pulled in and mixed with the return air so it can be conditioned prior to being introduced to the space also we can do 100 outdoor air in the case of flight cooling so the picture bottom left shows 100 outdoor air unit that maintains temperature of electronics while sitting on the tarmac which is the systems on board that uav aren't suitable to maintain temperatures when you're sitting at up to 160 degree f conditions ecu design considerations air systems are a great for going redundant system either if that's for additional capacity part load condition kind of capacity or complete redundancy with air systems you can use plenums and ducts backdraft dampers to kind of manage those connections and redundant systems are great for unmanned or mission critical systems capacity ratings for ecu's is determined by the ambient condition so if the ambient condition is higher in temperature that will decrease the capacity as well as the return air conditions so temperature humidity airflow rate basically the more energy you bring back to the unit the more cooling it can do so when you when you think you know what load you need understanding return conditions understanding the ambient conditions will affect the rating of that equipment and when you're evaluating solutions you really want to understand what the capacity you're being told is is based on somebody may call something a five ton unit that we would call a three ton unit depending on the rating conditions uh airflow pattern in the space is also very important these drawings kind of show a couple different ways the airflow could be managed on the left you have short cycling so you have air coming out of the ceiling goes right into a return and occupant and the loads don't see all of that air on the other hand the far right is really how you'd want to do a data center or electronics type environment where you're providing cool air to an occupied space that's then available for the electronics and the heat is then directed directly back to the unit because as we just said the hotter the air to the unit the more capacity you get out of that unit so um the way a unit's connected to a space the way the air is moved through the space is critical and making sure that the defined requirements um are actually provided to the equipment the equipment can actually meet the design into that another solution that we have experience with are glycol coolers and chillers glycol coolers we refer to here as liquid to air systems um basically provide cooling liquid at some temperature above ambient so these are a coil a fan a pump and basically a radiator where we can provide electronics with a a cooler than you know their we're providing liquid cool enough to pull the heat away from them and keep them happy but we're not providing coolant that's below the ambient temperatures alternatively we can do chillers chillers provide cooling liquid at a fixed supply temperature so we can provide let's say 45 degree fahrenheit glycol even when ambient temperatures are much higher than that so that is uh good for electronics to require low ambient temperature cooling as well as fixed temperature cooling um so there may be something that's calibrated uh needs to have a constant temperature uh design considerations for glycol coolers and chillers um you know when you when you go to a glycol system you have to make sure that the components in the system are designed for that right so you need heat sinks that accept glycol electronic equipment designed for a chilled fluid piping and fittings that don't leak are obviously important if the system is modular quick disconnects are needed so that you can disconnect um system components either for maintenance or replacement or if you're going to strike a system for relocation weight also needs to be considered when you're adding fluid you know an air system obviously there's no additional weight penalty to the volume of the duct system uh but with a glycol system any any storage any piping would be filled with glycol and therefore that weight would be a consideration in addition glycol storage tanks or pcms phase change materials can be used for thermal storage this makes a lot of sense when you have a system that doesn't have a continuous load you can downsize the system to deal with the average load and use the storage volume to address intermittent loads this is great when you're looking at directed energy weapons where the peak load may only be present for a few minutes out of an hour devin will tell you a little bit about a previous application like this thanks matt this is a case study for a direct energy weapon combined vapor compression and chiller system so this is using the phase change material so this is the solid to liquid energy storage mechanisms this would be latent energy storage as compared to using a sensible which would be just a giant liquid tank this is for a direct energy weapon mounted on the back of a humvee as seen in the bottom left there and really what we're showing is how tightly packaged a system like this can be if you needed to size the vapor compression system for the peak load of the laser in this particular application the entire system would have been twice this size so we were able to significantly reduce the size of the vapor compression system by coupling it with a energy storage media like pcm and then also including the chiller system inside of this box um this entire package you can see mounted on the left-hand side of the humvee here includes all the pumps all the fans all the electronics all the paper compression components all of the sun within one package so it makes a very complete thermal management solution for highly transient uh pulsed energy loads next we're going to switch gears a little bit here and talk about a different type of cooling technology this is similar to what matt was describing as our glycol coolers except this is what we call pump toothpaste cooling so it's an above ambient liquid cooling solution but in this case we're allowing the working fluid to boil or change from liquid to vapor as it flows across the heated components so it includes a pump it includes a condenser an evaporator and a reservoir a lot of the same components that a glycol system would have but the working fluids are typically refrigerants or dielectric fluids that boil at a relatively low temperature and pressure they are hermetically sealed systems so we can allow that boiling temperature to fluctuate depending on what pressure we impart on the system which is really a function of how we cool the system so they can be paired with some of the chiller solutions that matt was mentioning earlier so that we can do below ambient cooling but the system by itself is not capable of doing any refrigeration we really need that refrigeration cycle coupled to the condenser in order to get below ambient conditions so some of the benefits of two phase over a glycol chiller most of them revolve around energy efficiency so because we're using the weight and heat of the working fluid instead of the sensible heat like we would in glycol chillers or coolers we're able to use a significantly lower flow rate of the fluid orders of magnitude lower in fact and so that allows us to really shrink down the pump that's required for the system for packaging reasons it allows us to spin the pump at lower speeds and it allows the system to run with our energy consumption so that's a big benefit another benefit is that because again we're changing phases this all happens at a constant temperature as you boil the fluid and move from a sub-cooled liquid to a saturated liquid and eventually vapor that all happens along a constant temperature one and so as you're flowing across the evaporator the components mounted to that evaporator see a constant temperature which is not the case in a glycol cooler where the fluid's heating up as it's flowing from one side to the other so if you have multiple components i'll mount it to the same evaporator they can all be with maintained within about five degrees c of each other and then we can maintain 10 degrees c uh temperature difference across the entire loop so highly energy efficient uh method of cooling there's a lot of considerations that are different from a glycol system or a sensible cooling system to be discussed when talking about pump two phase the first is the heat absorption devices we call them evaporators because we're changing phase and these are very similar to the evaporators you may see in a chiller or vapor compression system they could be conduction based meaning you mount your heat generating components directly to those parts or they could be air to refrigerant heat exchangers much like an evaporator coil would be in a standard air conditioning system or it could be some combination of those and there can be many different evaporators all within a given system one challenge that comes up with two-phase cooling when you have multiple parallel evaporators like we're showing in the bottom right image here is that you have some flow balancing issues to deal with if you have one evaporator that's dissipating more energy than the other then the fluid will boil more in that evaporator compared to others it'll create more pressure drop and then you have this sort of unbalanced pressure balance in your manifold that you need to deal with the way we deal with that is we add flow restrictors to the system so that we can run as many parallel evaporators as necessary all at different loads or no load at all and be able to provide constant flow rate to all of them another consideration that's unique to two-phase cooling is refrigerant or working fluid selection in a pump two-phase system it's a little counter-intuitive but the pressure drop across the loop actually um results in a thermal resistance change as we drive around the loop the pressure decreases and then the temperature of that fluid also decreases and so that reduces the amount of temperature gradient we have to get that energy out of the fluid and into the air so that combats the uh the thermal resistance of the system requires us to have bigger condensers more airflow things like that so what we're really trying to do is minimize the pressure gradients around our loop in a two phase system in the top right we're showing an example comparing r134a to r245fa they're two different vapor pressure refrigerants that could be used in a pump two phase system r134a is significantly higher in vapor pressure so at 50 degrees c operating point the resulting pressure drop of 10 psi around a loop only has a one or two degree c temperature impact but if we were using a fluid like r245fa at that same temperature a 10 psi pressure difference across an evaporator could have up to an eight or nine degrees c impact on our system performance so picking the right working fluid for the right application um in the right conditions is really critical and it's something we take a lot of care with when we're designing these pump tube based systems another uh instance that we need to keep uh in mind with these systems is that the refrigerants are ozone depleting a lot of them there are new low global ring potential replacements for a lot of fluids we're showing some of them here if that is of concern for your system we have a number of fluids in our repertoire that have either zero or very low global warming potential that we can use the last note is uh related to pumps which comes up a lot when we're talking about pump two phase systems uh refrigerants tend to be very low viscosity fluids and we're operating very close to the saturation point of those fluids so pump cavitation and pump performance is a real concern we try to select pumps that have very minimal net positive suction head and psh and we're usually using pumps that have positive displacement to make sure that they can accommodate low viscosity fluids it's always a consideration to make sure we're getting the right sub cooling in the loop so pump two phase systems really are a system level design you can't design one component without consideration for the rest some applications of uh pump two phase a lot of them are electronics related what we're showing uh in the larger image on the right is actually what we would call a current distribution unit or cdu for a very large data center application this is a 200 plus kilowatt um condensing unit and in this case it happens to be a liquid cooled condenser so we're using facility water or whatever water source is available possibly from a chiller to cool the refrigerant down to the saturation temperature that we want to send off to the servers to do our cooling right below the condenser which is that large orange rectangle at the top is a reservoir because we're changing phases from liquid to vapor there's a volume change that needs to be accommodated and so we need some volume in the system to account for that difference in density and then all the way at the bottom are our pumps they tend to be n plus one redundant depending on the system we're working on uh positive displacement pumps distributing that liquid to all of the many servers that this system serviced in this case i believe it was servicing up to 40 individual server blades all from one central pumping so that's what i mean when i say we can handle multiple parallel evaporators as long as it's designed appropriately some other applications on the bottom there are utilizing either air or liquid as their condenser in the middle is a large uh 30 kilowatt coolant distribution unit with a sort of uh residential air conditioner style condenser coil that's u-shaped that we're using to dissipate the energy to the ambient air so these things come in all different shapes and sizes and can be suited for any application and there's also the ability to combine pumped two phase with vapor compression because they're often using the same refrigerants to be able to do some sort of hybrid energy efficiency refrigeration cycle so you can use eco mode and pump the refrigerant to the evaporator when the ambient conditions allow for it and when the ambient gets too hot you turn your compressor on to be able to do sub ambient cooling to keep your system at optimal temperature all year we talked about phase change materials a little bit in the direct energy weapon application but there's other applications for this they can be used to supplement air or liquid systems um as well as electronics they're really we would consider these thermal batteries or thermal capacitors so any system that has a transient thermal load can benefit from having a phase change material to damp out the peaks and valleys of that load in a glycol system the pcm like we talked about can help reduce the swap of the system to damp out those pulse loads and minimize the size of the rest of your components a key thing when utilizing phase change materials is that they're often fairly poor thermal conductors on their own and so they require quite an infrastructure of thermal pads in order to distribute the heat into them evenly and utilize all the material we're showing an example of something like that in the bottom left where we're using sort of a folded thin structure in order to distribute the heat evenly throughout all the phase change material so that you're really utilizing all that extra mass you're adding to the system if you don't have something like this in place then you wind up with clumps of solid and liquid material in there and you're really not getting the weight optimization that you're looking for so phase change materials come in all different temperature ranges a big benefit here is that again this solid to liquid phase transition happens at a constant temperature and so while you're absorbing all that energy of your transient load you're not increasing the system's temperature or components temperature we're showing that schematically on the plot on the right here you increase in temperature all the way up to the melt point of that material and then you flat line while you absorb all the latent heat and then once you have melted all the material the temperature rises again and you're back to sensible heating now in liquid phase instead of solid phase but that melt zone is really where a lot of the energy is absorbed and where you get the biggest bang for your buck out of these materials schematically at the bottom we're showing another example of this sort of pulsed energy system where the peak load is shown by the red bars and this is the energy that would need to be dissipated by a vapor compression system or an equivalent chiller if you didn't have some sort of thermal capacitor in the system the blue lines is showing the damped out load and you can see very clearly that having a load shaped thermal profile reduces significantly the load on the overall system and so all those components get smaller they get more energy efficient and your system becomes more optimized the last thing to note about phase change materials here is that they come in almost every degree c increment from negative 60 degrees c up to positive 400 and almost everything in between those are not all the same type of material so materials compatibility is a real consideration here but there's lots of options for for how you implement these materials into your system so i'll hand it back to matt to talk a little about our controls and electronics um so when we put together controls package one of the things we have to start with is what are we trying to control for air systems if you're doing an occupied space you might do return air might kind of function like a house residential style system where you're basically looking at the air coming back and once it gets too warm you start to cool once you get too cold you turn it off so you can cycle on and off we also have modulating systems either through the use of a digital compressor or an epr valve and that gives you a tighter temperature control um supply air or supply glycol control can be used for electronics and there you really do want to have a managed flow path so if you know that the air you deliver to the space or the liquid you deliver to the system will go directly to the loads that that temperature can be increased uh which optimizes performance of the system when you have poor distribution that's when you have to supply colder air because it'll get mixed before the electronics actually see it sometimes there's a critical location in the system so we might have a temp sensor directly at a piece of equipment and you might control the whole system just to keep that one piece of equipment humidity again can be a control point we may use hot gas reheat or electric reheat to over cool the air and reheat the air to bring out moisture power draw and inrush events are also something to consider with the control strategy if if there's not vfds in the system then you really don't want to bring on a big load at a at a time when a brown out to the power system could cause issues to other system components so we have systems that will operate continuous compressor and that's not energy efficient but that is good to keep the power system stable uh if you're doing some sort of scanning or radar activity where you can't deal with reduced voltage fan and pump speed modulation also may be used in the system um we do have systems that will ramp down the airflow to the shelter when the cooling load is not at its greatest a lot of these shelters are not very large they pack a lot of cooling load into a small space and so it can almost be a wind tunnel in there at times so anytime you're not in that worst case condition to back off airflow does make the interior environment a little nicer we do have different types of controls we use here electromechanical controls um digital digital temperature controls as well as plc where we can basically come up with any custom control configuration that's required uh local control interfaces could be as simple as an on off switch or red to blue dial uh to a touch screen that allows you to change set points by tenths of a degree remote connectivity is also something that we can provide uh can we can do ethernet based communication modbus snmp tcp ip as examples and use discrete connectors and have analog signals to report temperature discrete signals to report specific conditions or faults so uh to summarize kind of our capabilities um you know we want to be involved in the project as soon as possible we want to help steer the system level design to make sure that all the components can be optimized so really getting involved at the requirements definition stage is ideal but we go through the kind of normal military design cycle with pdr and cdr uh cdr phase critical design phase uh we'll work on mechanical packaging for the environmental requirements we're very familiar with mill standard 810 testing for shock and vibe um all kinds of environmentals blowing uh sand and dust snow wind salt fog um we've gone through lots of emi testing that really is something that is unique every time we do a design we always recommend if there are strict emi rfi requirements that we do those by test we'll also do reliability analyses at the cdr phase then you know we will procure the materials based on any flow down requirements uh and get into manufacturing we do test 100 of the equipment we make for thermal performance at increased ambience we do that in house and we will go outside for qualification type testing based on the environmental requirements system support is then offered with o m manuals spare parts and replacement procedures and we deal with component obsolescence as we help to support these systems for up to 15 years 20 years we offer training services and support and repair and reset uh i hope everyone's been asking questions as they have been going here but i think we have a poll that we're ready to introduce yeah thanks man we're going to take a couple minutes here to uh to send out a poll survey here you'll see it pop up on your screen please feel free to answer that and if you have any questions relating to our talk or really anything and put them into the chat box here and matt and i will be answering your questions live in a couple minutes thank you matt and devon for sharing this information and thank you to everybody who participated in our poll this time we're going to transition to the question and answer portion and thank you again to everybody who's made questions throughout the throughout the presentation and feel free to continue asking questions and we'll get to as many as we can so our first question here uh how do you recommend determining the actual electronic fluids in the system well that's a great question you do want to consult any manufacturer's data first they're going to be the experts on their equipment but anytime you can run a system and collect power draw it'll give you a good idea what's happening you don't want to just add up worst case loads and assume they all happen at once all the time that's a sure way to oversize your system and that causes all kinds of problems with control so we definitely try to guard against that yeah it's also important if it's an electrical cabinet to consider the loads from the ambient this gets neglected sometimes when we're sizing components like enclosure coolers and things like that it's important to consider the the solar loading on the cabinet any natural convection loadings if you're in a hot environment the electrical loads are definitely one of the main components but those things can't be neglected either so make sure you're considering all the potential loads like matt went over in the slides earlier all the loads that could be in your system to make sure you're really getting a complete thermal solution how do you deal with low thermal conductivity of gcm resulting in a relatively long melting time i think you should do that we talked about this a little bit in the uh in the talk so pcm materials most of them are are pretty terrible thermal conductors and so what you're really trying to do is to short-circuit the pcm as much as possible thermally and so that typically requires having some enhanced surface area inside of the pcm material you want to embed high surface area materials with phase change material try and minimize the conduction path as much as possible that'll give you the best result in terms of how much pcm you need in your system and how efficiently it reacts over time it'll also minimize your your melt times if you have to conduct through a poor thermal interface like a liquid layer of pcm before you get to the solid that's only going to slow things down and it's really going to increase the temperature gradients in your system so it's really a system level solution some people think that phase change materials are as easy as dumping some wax in a box and that's um that's not quite going to get you there it's really a highly engineered system so we make sure we take all that into account do you ever work with sterling cycle coolers the the short answer to that is not really we have done some cryo cores in our research and development group so sterling cycle using cryo cores but most of our refrigeration systems are the ones matt was describing where they're vapor compression based um really the sterling coolers tend to be more for cryogenic applications and we don't see a lot of those it's not to say we wouldn't do it uh we just haven't done done a lot of it today can you talk more about how cooling data centers um and how to cool data internal cool there's a lot of ways i'll talk about the liquid cooling maybe you can talk with the aircoin yeah um so we did mention that pump two phase application which was for data center cooling that's kind of the new wave of handling these these really high heat load high performance computing type of data center applications and the reason pump two phase is really suitable for that application is that it's capable of absorbing a lot of energy with a small amount of energy input so it's above ambient cooling solution so a cooling tower or some ultimate rejection system is needed on the roof of your building but at the server level you're really picking up the most amount of energy or heat per unit of energy input into the system using um pump two phase coiling or some sort of liquid to vapor cooling technique and so when energy efficiency is really the the name of the game and data centers that that gets you where you need to be at the server level yeah i mean even if you have chill water in the building you know a lot of people are not going to feel comfortable putting chill water into this into the server area so a heat exchanger to a two phase pumping system one of the benefits of that refrigerant is if you have a leak it'll it'll leak as a gas so you're not going to have conductive liquid all-over electronics if there's a leak so i know that pump two phase even with the chill water system is still kind of preferred at the load and like you said with the continuous or the constant temperature across the heatsink it really allows for optimized equipment um from an air system side um hot oil cold aisle might be terminology you're familiar with and this is really about making sure that the cold air from the crack units or whatever the air handler is called in the system is delivered to the inlet of the equipment and then the hotel would be where the racks blow everything out so you know one of the things i've seen in some kind of tactical systems is you have a hodgepodge of equipment some have fans in the front pulling in some have fans in the back pulling in and so now you you don't have all the equipment even pulling from the same side so very quickly you can have a piece of equipment that gets the heat from another piece of equipment and isn't happy even though you know the air handler attached to the system is about a quick capacity there can't get to the electronics you have trouble so definitely taking into account the direction of airflow and management of the airflow for the electronics is a big thing and our last product coming back to the energy efficiency part for data centers that we didn't talk about today is a product called a wraparound heat pipe heat exchanger and this is actually incorporated directly into the air handlers for the crack units and what it's helping to do is to enhance the dehumidification of the system so you can do some pre-cooling some free reheat on the system we also have air-to-air energy exchange products where you're recycling that air through the data center and you tend to be throwing away cold air that's already been conditioned you can use that energy to pre-cool the hot air from the outside without needing to input any more energy into the system and so it can improve the overall energy efficiency of your data center even if you're still using air cooling it could even work with the liquid cooling systems so that's quite a lot of technologies for for data center applications what is the max power that can be removed in two-phase cooling from an asic by 20 millimeter with exposed dye that's a great question um we have done some asic cooling it's um i'll i won't talk specifically i guess to that die but we have developed pump two phase coin solutions for up to about 300 watts per centimeter squared um cooling applications it it depends a lot on the the type of application it depends on what your maximum temperature can be and how exotic we get with the evaporator we've done some true micro channel cooling evaporators for pump two phase where we can get even higher heat fluxes it's a little bit r d um if the question is referring to immersion cooling so direct cooling of the junction itself we have a little bit of experience again that's more r d but you're impinging the refrigerant directly onto your exposed chip and you can do that because they're dielectric fluids and they won't short out your system the word of caution there is that surface area tends not to be sufficient when you're doing immersion cooling you want a lot of surface area to distribute that heat flux to the fluid or you start to create vapor bubbles very rapidly on your surface and then it creates this sort of critical heat flux situation where you're impinging liquid onto a vapor bubble and it's not really hitting your heat source so there's a lot of considerations there that's a very challenging problem but we do have experience with very high heat flux microchip microchip cooling applications what is the realistic duty factor for heat load from the equipment power draws that's a tough one um you know i know sometimes uh we like to use like whatever kw is being pulled into the equipment is the kw of heat we have to reject obviously theoretically that doesn't make sense because some meaningful work is happening um so we tend to use like an 85 percent as a rule of thumb but really it's going to depend on the application the actual equipment oh it looks like we're having time so as a reminder if we didn't have time to answer your question we'll be following up with an email additionally if you think of any more questions or if you'd like to schedule a call with our engineering team to discuss thermal management needs for your ongoing projects you can send an email to solutions at 1-act.com thank you
all again for attending today's webinar and we hope you'll join us again soon have a great day you
2021-12-01 05:52
