[Equest-users] VRV with and without simultaneous heating/cooling

Nick Caton ncaton at smithboucher.com
Mon Dec 2 11:50:12 PST 2013


I don't know of a good direct answer, but have a few thoughts... if a VRV system can only heat or cool all its cassettes units at any given time... that's effectively a multizone split heatpump system right?  (example:  http://www.lennox.com/products/mini-split-systems/MS8Z/) 

eQuest currently has the option for a single zone split heatpump system... you could assign one of those per zone and probably come close - but the difference would be where some zones need heating and some zones need cooling this approximation would actually deliver that instead of being able to do only heating or only cooling (so you'd have to acknowledge this approximation models better comfort).

On a related point, I think in comparing the two options you should consider looking to define both an annual energy/cost difference, but also a difference in "unmet hours," from a comfort perspective.

Another thought:  I know folks have used eQuest to construct 2-pipe fan coils (starting with a 4-pipe system, re-assign to a 2-pipe loop, and then use schedules to define changeover criteria)... you might construct your VRV model, then extrapolate the "relative" performance/comfort difference between the ability to provide simultaneous heating/cooling and just one or the other by doing so with waterside systems in that fashion.

Food for thought =).

~Nick

NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com 

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of The Watt Doctors - Dave Weigel
Sent: Sunday, December 01, 2013 11:43 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] VRV with and without simultaneous heating/cooling

Hi Friends,

I'm needing to model VRV system with and without simultaneous heating and cooling. I'm familiar with the PVVT / variable speed compressor technique, but modeling both circumstances has me a bit puzzled.  Can anyone shed light?

Good on ya,

Dave 

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