# Would Anyone Like to Share Cheat Sheets?



## JoeysVee (Sep 16, 2009)

I have 1 page of various equations, 1 page of Mechanical Systems equations, 1 page of Thermo/Fluid Equations, and 1 page of HVAC equations that I'm putting in the front of a 3 ring binder (the binder also has the MERM and ASHRAE indexes in it) and was wondering if anyone else is also putting together a short list of equations like I am. I will go to these sheets when I know the equation I need on the sheets...this will eliminate going to the MERM and flipping on every single problem.

If you are creating similar sheets and want to share reply to this thread. Thanks!

arty-smiley-048:


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## Shaggy (Sep 16, 2009)

I created cheat sheets in school for various tests (they were allowed btw). I bound these for the PE and prep and actually used them. The sheets were useful because they were created based on the methods that I learned, rather then re-learn a comparable method of MERM's choosing. Similarly, someone elses cheat sheets may not be as effective as sheets created by you. I will try to scan and post my book of formula sheets within a couple days.


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## justin-hawaii (Sep 23, 2009)

Here are some of the things that I included on my cheat sheets (I took HVAC and Refrigeration back in October 08)

I don't have the actual sheets on me right now but here's what i remember:

A picture of a psych chart, with arrows pointing in the direction of dehumidification, humidification, heating, cooling and all the combinations.

Q=mc(Delta T) - for air: Q=1.08(CFM)(Delta T)

Constants = 8.314 lb/gal, air 13.75 ft^3/lb, h20 = 62.4 lb/ft^3, etc.

Enthalpy wheel effectiveness equation

Condensate removal equation

A picture of a vapor compression cycle - ph diagram - showing things like condenser heat rejection, de-superheat, superheat, constant entropy line, refrigeration capacity, etc. How the PH diagram relates to condenser, compressor, evap, expansion valve.

Range, approach, efficiency of cooling tower equation.

air washer saturation

friction head, velocity head equation both for psi, ft head.

HP equation for both fans and pumps

number of poles/rpm equation, specific speed equation

Relative humidity equation

Q = 4.5*CFM*(Change in enthalpy)

Humidifier equation

Sound equations - check ASHRAE

Vp = (V_fpm/4005)^2

Speed of sound equation

Buoyancy

Carnot efficiency equation

Mollier diagram showing things like steam expanding isentropically, etc.

Heat exchanger effectiveness equations

Pump/fans similarity equations

Bypass factor equation for coils

A bunch of steam sample problems

kinematics

elastic deformation

thermal expansion

combustion cycle diagrams -otto, carnot

Principle stresses

Pressure vessels


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## Master slacker (Sep 23, 2009)

I didn't think a cheat sheet was necessary. After doing as many problems as I did, I felt very comfortable with my resources and where all the information / equations were. You may or may not have a necessary equation on your sheet, which in the end, will cost you time as you'll have to go to a reference anyway. My $0.02.


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## Agg97 (Sep 23, 2009)

Master slacker said:


> I didn't think a cheat sheet was necessary. After doing as many problems as I did, I felt very comfortable with my resources and where all the information / equations were. You may or may not have a necessary equation on your sheet, which in the end, will cost you time as you'll have to go to a reference anyway. My $0.02.


Ditto that.


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## justin-hawaii (Sep 23, 2009)

I agree that it would be difficult to capture all the necessary equations for the test and you will definitely have to turn to your references(so be able to navigate them with ease).

Cheat sheets can be a good study method. They are a great way to (1) summarize your months of studying, (2) put to paper what you think are important formulas, principles and concepts and (3) bring to light concepts that you might not completely understand.

Just my thoughts.


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## MechGuy (Sep 23, 2009)

Agg97 said:


> Ditto that.


I agree, I don't think a cheat sheet is necessary. I just used the Shaggy method of tabbing my MERM and could find everything I needed.


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## JoeysVee (Sep 24, 2009)

My MERM is tabbed like crazy but some of the most frequent equations and conversions are captured on my cheat sheets which are quicker to get to than flipping through the MERM. I have never finished a sample exam or the real thing in 06 so time is critical to me. I have a 3 ring binder...the first thing is the cheat sheets followed by a MERM index and the ASHREA index followed by Psych charts.

Thanks for the opinions.

If anyone else is creating these same type of equation sheets let me know. Thanks!


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## buick455 (Sep 25, 2009)

I do not have a cheat sheet but I have developed my own quick reference booklet. I was hesitant about including the actual equations in my booklet as there are many equations to use and I thought it would be better to just go to the page where they were. Due to the somewhat complex nature of the MERM I do find my quick reference very handy and I complement that with the tabs. To be honest, as I have gone through the MERM so many times I can almost remember where most of the equations are. I do wish SI was not on this exam as it just adds another level of confusion which I feel is not neccessary.


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