[Equest-users] Curve Coefficients

[Nick Caton]

To clarify the ongoing discussion and reinforce my earlier response to John's query:

 

Standard ARI rating conditions (*) for packaged AC/heatpump equipment are 95°F DB entering at the outdoor section (outside air), and  67°F WB entering at the indoor section (the mixed air conditions entering the coil).  If I'm not mistaken, those are the corresponding drybulb and wetbulb temperatures to be referenced when normalizing to and creating any of the DX performance curves that use temperatures as variables.

 

(*) See Table 3 on page 10 of the AHRI document Maria Karpman linked recently on bldg-sim (copied below).

 

~Nick

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: Maria Karpman [mailto:maria.karpman at karpmanconsulting.net] 
Sent: Tuesday, February 01, 2011 10:07 AM
To: 'Karen Walkerman'; Nick Caton
Cc: 'bldg-sim at lists.onebuilding.org'; 'Sam Mason'
Subject: RE: [Bldg-sim] ASHRAE Appendix G EER Calculation

 

Karen,

 

You can download ARI 340/360 referenced in the rightmost column of ASHRAE 90.1 Table 6.8.1 A from http://www.ahrinet.org/App_Content/files/standards%20pdfs/ANSI%20standards%20pdfs/ANSI%20AHRI%20340-360-2007.pdf (it's free). Section 6.1 of the ARI standard reiterates that indoor fan power must be included in the rating, which is consistent with definitions in 90.1 quoted by Nick. The section also provides standard fan power of 365 W per 1000 CFM (see top of page 11), which is used in eQUEST EER to EIR conversion paper that I emailed yesterday. The equations in the paper are principally the same as in the ASHRAE User Manual section that Sam sent to the forum, except the rating conditions are used for fan energy.  

 

Thanks,

 

Maria 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Saturday, February 05, 2011 2:55 PM
To: Grando, John
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Curve Coefficients

 

Sorry, hit the wrong button. I'm not sure which volume the equations are in but I'll see if I can find and send to you.

 

Carol

On Sat, Feb 5, 2011 at 12:54 PM, Carol Gardner <cmg750 at gmail.com> wrote:

Hi John,

 

The entering wet bulb temperature for the outside air. You will normalize the curve around whatever that is to meet the ARI design conditions, 67F maybe, I can't remember off the top of my head. There is a full set of equations for equipment under Curve-fit for HVAC Equipment, but I'

On Wed, Feb 2, 2011 at 10:17 AM, Grando, John <JGrando at cosentini.com> wrote:

	I'm basically trying to figure out how eQUEST comes up with the total Electric consumption for a DX coil.  I thought it was the below

	 

	Total Capacity * Capacity Curve [T] * Total EIR * EIR Curve [T] * EIR Curve [PLR] but it's not coming out exactly the same.  Does anyone have any input for what I'm missing.  The attached .xls is an example for one day.  The total capacity is 79.983 kBTU/Hr and the EIR is  0.2722.

	 

	 

	 

	John Grando LEED AP| Mechanical Engineer

	Phone: 212-615-3705 | Fax: 212-615-3700
	jgrando at cosentini.com
	
	Cosentini Associates - A Tetra Tech Company
	Two Pennsylvania Plaza - Third Floor - New York, NY 10121
	www.cosentini.com <http://www.cosentini.com/> 

	 

	 

	 

	
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-- 
Carol Gardner PE




-- 
Carol Gardner PE

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