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  • Design application of a low bed under grill refrigerator.

    Don Ross

    Don Ross

    @don-ross-A3oedi
    Updated: Oct 21, 2024
    Views: 1.2K
    Design application of a low bed under grill refrigerator.
    I just designed and quoted a remote system to replace a
    system that is installed inside the unit.
    The only way to get to the compressor was to break the gas grill line down
    and tear the top off., Now this restaurant
    runs 7 days a week so I am always working at night or under their feet.
    So I just designed a unit to hang from the
    ceiling above the prep area.

    Now I would like to discuss the variables
    I took into consideration. I have no spec's
    on the unit so I went on line and matched a comparable unit size. Then I considered
    the politics involved and the
    heavy usage when it's 80 degrees on the line.
    They have AC or it would of been 100 degrees. The compressor is inside and is small
    about a 1/2 to 2/3 hp.
    But my experience told me it should be a 3/4hp.
    Now when pricing the
    unit I found a 1 hp to be the cheapest at 850 vs 1150 for the 3/4.
    Yes no rhym or reason for costs being different.
    That's why PE engineers build expensive systems. They don't obtain real world pricing.

    Now you say
    Oh my! it's to big is it really? The 1 hp is 12% larger in btu capacity.
    Which I will need to offset the 50'
    length of pipe besides it will work less and run about the same amperage in the field.

    Now lets talk refrigerant selection.
    The existing system is a 134a refrigerant. The same as in a car.
    Now after 15 yrs they are going to ban it because smart people where not that smart
    and it's bad for the ozone. lol Idiots.

    I could put in a R404 system. The inside components will handle it especially since
    my capacity is higher and
    my evaporator pressure (temperature) is lower to offset the losses in the personalities of the refrigerant.
    I really would love to use r22. It;'s a superior refrigerant to any other.
    But we will stay PC (Politically correct)

    Now if I run into a freeze up of the coil problem I can always slap a EPR valve on it.
    EPR is a evaporator pressure regulator which throttles to maintain a high, not freezing suction gas temp.
    Temperature and pressure go hand in hand.
    The lower the pressure, the lower the temperature unless you start super heating it.
    But that's another discussion for another day. Any questions?

    Ok I sold the system and ordered the compressor. I went with R22 lol. The hell with PC lol I like R22 and if I have freezing problems I will swap it onto R22b which has a higher suction gas temp per pressure temp. Should work. The R22 will give me almost double the temperature drop. It will kick ass. lol
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  • Don Ross

    MemberFeb 9, 2015

    The system is in and running on 404a. And it runs wonderfully. It has given me a new understanding of 404. It is kicking butt, lol. now the R 22 would of kicked double butt but in reality it would of been to powerful a refrigerant for the application. Now remember if you take up this trade( which is a wonderful and very small engineering trade, which is why it makes me as one of the most knowledgeable in the world) you will have new fronts to battle and ever changing applications to tackle. Besides the fact that we have not even begun to reapply the new technologies to the field. Very Very exciting and rewarding. So my young engineers Think Think hard as to what you want to contribute to this world we call home. So good bye and good luck. For me I have a world to conquer. this was a vacation of my mind for me. lol. Go build a means to Mars. We humans have to get off of this rock if we as a species want to survive longer than our shelf life here.
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