HVAC Information - CR4 Discussion Thread

Home

Products & Services

Engineering News

Standards

Webinars

Engineering Forum

Login

CR4 Home | Mechanical Engineering | Mechanical Engineering

6 comments

Rate

Comments: Nested

Mushtaq Hussainh Commentator Join Date: Jun 2011 Location: Hyderabad, India. Posts: 92 Good Answers: 2	HVAC Information 09/02/2012 4:11 PM
	Dear HVAC Engineers, I would like to know the reasons for the followings: 1. Overall Coefficient Of heat Transmission symbol is used as "U" which is not related to title; why not other symbol OR Alphabet( I read ASHRAEs from 1980 till toady & 10 HVAC books but did not find the relation) 2. Al most all available HVAC Load estimation programs, Such as E-20; HAP, CHVAC & Trane express, estimate per hr HVAC load as BTU/hr. Why? When most of the loads vary in 1/4hr & 1/2hr in cooling space. __________________ B.E, M.I.E, M.S
	Register to Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Join CR4, The Engineer's Place for News and Discussion!

PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#1 Re: HVAC Information 09/03/2012 4:49 AM
	A1: Convention. A2: HVAC techniques originated substantially in the USA, which does not use SI ("metric") units. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
	Register to Reply

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#2 In reply to #1 Re: HVAC Information 09/03/2012 9:57 AM
	Whoa up there pard. It's a BTU, British Thermal Unit, not ATU, American Thermal Unit.
	Register to Reply

Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#3 Re: HVAC Information 09/03/2012 12:46 PM
	Ain't nobody around here old enough to remember why "U" was chosen. [?] __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
	Register to Reply

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#4 In reply to #3 Re: HVAC Information 09/03/2012 1:09 PM
	R U?
	Register to Reply

Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#5 In reply to #4 Re: HVAC Information 09/03/2012 2:12 PM
	I guess not; I'm only 63. __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
	Register to Reply

Yahlasit Guru Join Date: Dec 2008 Location: Cd. Juarez, Chihuahua, Mexico. Posts: 1023 Good Answers: 69	#6 Re: HVAC Information 09/03/2012 3:26 PM
	1.- U stands for a rate of heat transfer between two surfaces, or a surface and a flow per Unit of area, (A was already taken to denote area itself, so...). 2.- Duno, not that old. Regards __________________ No hay conocimiento ni herramienta que sustituya al sentido comun.
	Register to Reply

Copy to Clipboard

Users who posted comments:

lyn (2); PWSlack (1); Tornado (2); Yahlasit (1)

	Got Something to Say?
	Ask a Question Start a Discussion

	Search this Forum
	Mechanical Engineering: Go

CR4 Sections

	Aerospace
	BioMech & BioMed
	Chemical & Material Science
	Civil Engineering
	Communications & Electronics
	Education and Engineering Careers
	Electrical Engineering
	General Discussion
	Instrumentation
	Manufacturing
	Mechanical Engineering
	New Technologies & Research
	Software & Programming
	Sustainable Engineering
	Transportation

	Site Directories
	Forum Directory Blog Directory User Group Directory RSS Feeds CR4 Rules of Conduct CR4 FAQ Site Glossary Who's Online (95 right now) Show Members