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Thread: Newbie looking for advice on where to go in here

  1. #1
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    Newbie looking for advice on where to go in here

    I am new here and fairly new to the industry. I work for a manufacturing company as an engineer and have been tasked with designing a... well, it is sort of just a definite purpose chiller really. So far we are starting small (less than 5 ton), but we had one customer asking for a 200kW version... that was also mobile and would need to be ruggedized! That scared me - but I talked the sales guy into no-bidding that one.

    I had zero experience with HVAC equipment and had to study for a while to get my EPA cert - then go learn as much about the trade as I can while still trying to be somewhat productive on the design end of things. I have hired technicians to help my charge the system, and start it up, general troubleshooting etc. I worked with them the entire time and asked as many questions as possible, but I seem to have reached the limits of their capabilities (just the ones I have access to) and now I need a source for more engineering-level information. It will be very important for my product to be as efficient as possible because parasitic loads are a negative in the industry we are targeting and I have very little experience with optimizing for efficiency.

    What should I do to find any of the kind people (or not so kind, so long as they are willing to teach me) in here who have this type of knowledge? Also - I want to make sure I don't break the rules right away, so I will be looking for advice on etiquette as I try to get my 15 posts in for more access to learning. I am here to learn so if any of you want to teach, I am all ears.

    One more thing: I am keenly interested in the "don't do" subjects where I can see what people hate about certain manufacturers and/or products and do my best to avoid them. I want to make a product that is good to my customer and to the poor sob that has to work on it down the line. If you have posts you can direct me to on these topics I would certainly appreciate it. I will obviously use the search bar, but I just want a little help finding stuff and have to make some posts to get access to the rest of the site, so here it is.

  2. #2
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    You won't find a lot of help on here from the design engineering side. Don't let that discourage you because the type of information you want is well known to many here which from your post appears to be on the performance side. I don't mean it's not part of quality engineering because it is but not from a design standpoint from this site. You will have to apply the feedback you get to apply to your needs.
    You should ask your questions and see what the responses are. I think you will be delighted.
    I was a design engineer and speaking from experience. You are also going to need some good text books but I didn't do a lot of machine design and can't help there.
    No man can be both ignorant and free.
    Thomas Jefferson

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    Thank you for the advice - that is perfect. I can find some of the other stuff elsewhere - I love the perspective of the person having to install and work on the equipment. I am also the one having to do all of the work for now and will have to train workers on things like brazing eventually. I am building all of the prototypes for now including the show unit that will show off our "capabilities" at tech shows. I have been lurking on this site for a while already as most of the questions I post to google have a link here - but I figured I better dig a little deeper.

    I have all the old textbooks and many years of design experience in the industrial industry, so I am set there (but always looking to learn) - I am a complete newbie to HVAC though and it is not as simple as the sales guy made it seem when the customer came asking us for a temperature management system. Now he over-sold our capabilities and I ended up stuck with cleaning up the mess. Can't complain too much. I am still employed and definitely not bored! This industry is like no others though. I can find all sorts of information on almost all other established industries, but the engineering and design side of HVAC has been eluding me. If you know of any books that could help me on this subject - or trade groups to also join I would appreciated it! I went to AHR Expo the last couple of years and made many connections with potential suppliers, but most of them are also limited on what they will divulge for information. It is also hard to get their attention when I am not buying pallets of parts at a time. The company I work for is over 75 years old and we have a really great supply chain for all of our equipment - but not HVAC. I am having to find all of the contacts also... I feel like I am doing too much lol!

  5. #4
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    SocialLeper (what a handle that is),
    I won't even try to give you input regarding "Design" but having wrenched on stuff for almost half a century I will offer this;

    Once you get your prototype designed and built step back and look at it from the perspective of "Worst case service and Repair". What I mean by that is, if someone has to replace any part of the machine do they have "adequate" access and clearance to do so.
    Unfortunately outward appearances sometimes dictate internal component location. Reverse engineer your design, so to speak, as if next week you (or your team) will have to replace a Fan motor, compressor, exchanger or you have to add refrigerant or rewire/replace a bad contactor.

    A "Super Whiz Bang Chiller" may be the perfect solution to an end users requirements but if the Service folks simply hate working on it that (negative service feedback) may lead to not selling a second one to a customer.

    I hope you interpret this as constructive input.

    Best of Luck.
    If sense were so common everyone would have it !
    Never underestimate the power of human Stupidity !
    If folks took care of their cars like they do their HVAC Systems you'd see a lot more people walking !

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    Thank you for the feedback - I absolutely take it constructive and I did some of that before I shipped the last one and took note of all the “opportunities for improvement” I came up with along with what the service techs told me.

    I also have noticed that “whiz bang” is not always respected in this community - I will need to navigate this minefield carefully because I need to meet my customer’s demands for communication protocols with feedback along with the need to minimize parasitic loads - and maintain easy maintenance. This will be tough - but I hope I can find the right compromises to make.

    Again - thank you for the feedback! It is much appreciated.

  8. #6
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    Are you positive said chiller doesn't already exist?
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Why is it that those who complain the most contribute the least?
    MONEY CAN'T BUY HAPPINESS. POVERTY CAN'T BUY ANYTHING

  9. #7
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    The design of HVAC systems is the easiest in the mechanical engineering field. It is actually boring but design of the equipment is a different story. The guys here that install and service the equipment have a tougher job than the engineer that designs the system and have to know more about the machines than the system designer. That makes me wonder why so many system designs are screwed up.
    No man can be both ignorant and free.
    Thomas Jefferson

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  11. #8
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    Quote Originally Posted by WAYNE3298 View Post
    The design of HVAC systems is the easiest in the mechanical engineering field. It is actually boring but design of the equipment is a different story. The guys here that install and service the equipment have a tougher job than the engineer that designs the system and have to know more about the machines than the system designer. That makes me wonder why so many system designs are screwed up.
    Exactly. In its most simplistic form, all we are doing is moving heat from one area to another.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Why is it that those who complain the most contribute the least?
    MONEY CAN'T BUY HAPPINESS. POVERTY CAN'T BUY ANYTHING

  12. #9
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    What does definite purpose chiller mean? Tough to offer assistance or advice with the information presented.

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    Quote Originally Posted by 2sac View Post
    Are you positive said chiller doesn't already exist?

    It does - in different formats. We will have competition for sure, but we are trying to move in quickly and get our piece of the pie.
    Last edited by SocialLeper; 09-30-2020 at 11:08 AM. Reason: To add quote

  14. #11
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    By definite purpose I mean it is designed for a single purpose. A more general term would be a precise temperature management device. The chiller is only half of the equation - I have a tank of fluid I need to keep at a precise temperature to keep a “process” at a precise temperature.

    I know it seems a little weird, but I’m under so many NDAs that I can’t remember what I can and cannot say, so I have to be a little careful.

    Simply put - I have a tank of water that I need to keep at a certain temperature and be able to react to a process that may increase or decrease the temperature of my water. I can handle the heating easily for now with resistance heaters - but I will need to learn reversing valves and all the pitfalls that can happen there too so I can weigh my options.

    I truly need (and welcome) advice in any area you have expertise.

    What tools are crap in your opinion?
    What tools are a must-have?
    What design flaws are you guys seeing that make you not want to work on certain equipment?
    What are some techniques you’ve come across for proper bending and assembly of copper piping?

    All of these things will be appreciated - and advice on how to find the threads where all of these topics have been covered.

    Thank you for the response - I hope it is a little more clear now.

  15. #12
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    Quote Originally Posted by WAYNE3298 View Post
    The design of HVAC systems is the easiest in the mechanical engineering field. It is actually boring but design of the equipment is a different story. The guys here that install and service the equipment have a tougher job than the engineer that designs the system and have to know more about the machines than the system designer. That makes me wonder why so many system designs are screwed up.
    Me too - but it does get difficult when you try to squeeze more efficiency out of it. It is also all new suppliers so I really don’t know the reputations of the equipment or the companies well enough to not accidentally get us into bed with a crap supplier. I have no agreements yet, but I’m going to need them in the future to get good enough pricing. I don’t want to hitch my wagon to a crappy company.

    I also hear a lot of grumbling about mini splits - but they are really well designed from a manufacturing standpoint, so I want to avoid that same mentality that they fell into if at all possible.

    In short - yes, it is easy to spec some parts and make something that works, but the secret will be to make something that is easy to manufacture, easy to work on, intuitive to use, efficient, and reliable. No small order!

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  17. #13
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    Quote Originally Posted by 2sac View Post
    Exactly. In its most simplistic form, all we are doing is moving heat from one area to another.
    Agreed

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    Quote Originally Posted by SocialLeper View Post
    It does - in different formats. We will have competition for sure, but we are trying to move in quickly and get our piece of the pie.
    I would start by scrutinizing all of the competitors. Which are the most highly regarded, and why? How do technicians feel about servicing them? Are they using sub-assemblies that are available off the shelf? How many of the parts being used are custom built?

    How are the competitor's machines similar? Is there a better way to accomplish what they are doing?

    It sounds as though you are trying to build a better mousetrap, and that is admirable, but I think your best chance at profit is to build a more durable machine that is easier to service, and to have a lower price point. Efficiency is elusive because moving heat requires the same amount of work every time, and only energy losses can be reduced, but those reductions must be weighed against the cost of the loss reduction.
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  20. #15
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    Quote Originally Posted by SocialLeper View Post
    By definite purpose I mean it is designed for a single purpose. A more general term would be a precise temperature management device. The chiller is only half of the equation - I have a tank of fluid I need to keep at a precise temperature to keep a “process” at a precise temperature.

    I know it seems a little weird, but I’m under so many NDAs that I can’t remember what I can and cannot say, so I have to be a little careful.

    Simply put - I have a tank of water that I need to keep at a certain temperature and be able to react to a process that may increase or decrease the temperature of my water. I can handle the heating easily for now with resistance heaters - but I will need to learn reversing valves and all the pitfalls that can happen there too so I can weigh my options.

    I truly need (and welcome) advice in any area you have expertise.

    What tools are crap in your opinion?
    What tools are a must-have?
    What design flaws are you guys seeing that make you not want to work on certain equipment?
    What are some techniques you’ve come across for proper bending and assembly of copper piping?

    All of these things will be appreciated - and advice on how to find the threads where all of these topics have been covered.

    Thank you for the response - I hope it is a little more clear now.

    I suspect you have more of a how do I control this, rather than a definite purpose chiller thing.

    Sounds like a relatively common process control application. These type systems are everywhere. You need a feed forward control loop with a feedback control loop.

    To accomplish your goal you first need to calculate your maximum required heat gain / loss, throughout the process, and size your equipment accordingly.

    With no more information than we are provided, I'd suggest you might use submerged heat, and cooling coils, controlled by feed forward with feedback.

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  22. #16
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    Quote Originally Posted by timebuilder View Post
    I would start by scrutinizing all of the competitors. Which are the most highly regarded, and why? How do technicians feel about servicing them? Are they using sub-assemblies that are available off the shelf? How many of the parts being used are custom built?
    I am trying to do that, but in this specific industry there are none - yet. The hard part for me is that this is not my normal industry in both regards. I don't know your industry, and I don't know my customer's industry, so I end up kind of flying blind. That is why I am reaching out on this website to try and connect with people from the industry.


    Quote Originally Posted by timebuilder View Post
    How are the competitor's machines similar? Is there a better way to accomplish what they are doing?
    The tough part is that my customer wants all of the bells and whistles that they have heard of, but want it to be more complete (It is a complete system from soup-to-nuts - not just a chiller) and - of course - they want it as cheap as possible.

    Quote Originally Posted by timebuilder View Post
    It sounds as though you are trying to build a better mousetrap, and that is admirable, but I think your best chance at profit is to build a more durable machine that is easier to service, and to have a lower price point. Efficiency is elusive because moving heat requires the same amount of work every time, and only energy losses can be reduced, but those reductions must be weighed against the cost of the loss reduction.
    I agree that it must be robust - and must be better than the current competitor that is using a mini split system to change the temperature of the air inside the process instead of using a heat-transfer media like we are trying to do. There are ways to (at least on paper) make the process more efficient, but I am not well versed on it yet and want to avoid making a stupid mistake like designing my copper layout such that the oil does not get back to the compressor under certain loads etc.

    Thank you for your response - all of this is very helpful.

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    Quote Originally Posted by Artrose View Post
    I suspect you have more of a how do I control this, rather than a definite purpose chiller thing.
    I was only pointing out the section of my project that related to this board. I already created the control system on a PLC that we can use for a while, but I will soon work with our electrical/software engineers and design our own control board(s).

    Quote Originally Posted by Artrose View Post
    Sounds like a relatively common process control application. These type systems are everywhere. You need a feed forward control loop with a feedback control loop.
    It is common with the only exception that it will be tailored for the customer. Each version will have a completely different setup specific to the rest of the needs. I want to keep the chiller portion as much the same in each one though, so that creates an interesting design challenge for me. The sizing of each application may be different with different requirements for electrical loads etc - this could get annoying if this industry is anything like the current industry I work in.

    Quote Originally Posted by Artrose View Post
    To accomplish your goal you first need to calculate your maximum required heat gain / loss, throughout the process, and size your equipment accordingly.
    I am working with my customer right now to do testing to validate the thermal FEA we already did on this. Hopefully I got it correct...

    Quote Originally Posted by Artrose View Post
    With no more information than we are provided, I'd suggest you might use submerged heat, and cooling coils, controlled by feed forward with feedback.
    I am using a brazed plate heat exchanger for my evaporator. I mounted it on a plate next to my accumulator for the first 2 prototypes - including the one I sent to my customer, and then realized I was just wasting insulation and time - why not put the damn thing inside the water? I literally came to this conclusion last week and started designing a new system with the evaporator immersed in the liquid. Ugh - wish I would have found this board earlier! As far as controls - hopefully I am good on that, but we will have to see once the testing gets going.

    Thank you for the answers!

  24. #18
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    Thanks guys!!! You made my prediction in post #2 come true.

    The only problem is you guys make me feel unneeded but I love it.
    No man can be both ignorant and free.
    Thomas Jefferson

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  26. #19
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    Any advice on components or strategies to avoid? I know you all have that one piece of equipment you see at the job when you arrive and a chill goes down your spine because you remember what a pain in the ass it is to work on... What is it and how do I avoid designing one of those?

    What are some of the things that you wish you could tell the damn design engineer about how stupid they were for doing something?

    What is something you wish every design engineer would do that would make your life easier?

    Any and all answers are appreciated - thank you all for the advice so far!

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    If you have a wide ranging unpredictable load...a big buffer tank is cheap and covers a lot of sins.

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